Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/exec.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * #!-checking implemented by tytso. |
| 9 | */ |
| 10 | /* |
| 11 | * Demand-loading implemented 01.12.91 - no need to read anything but |
| 12 | * the header into memory. The inode of the executable is put into |
| 13 | * "current->executable", and page faults do the actual loading. Clean. |
| 14 | * |
| 15 | * Once more I can proudly say that linux stood up to being changed: it |
| 16 | * was less than 2 hours work to get demand-loading completely implemented. |
| 17 | * |
| 18 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, |
| 19 | * current->executable is only used by the procfs. This allows a dispatch |
| 20 | * table to check for several different types of binary formats. We keep |
| 21 | * trying until we recognize the file or we run out of supported binary |
| 22 | * formats. |
| 23 | */ |
| 24 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/slab.h> |
| 26 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 27 | #include <linux/fdtable.h> |
Hugh Dickins | ba92a43 | 2008-07-25 01:45:43 -0700 | [diff] [blame] | 28 | #include <linux/mm.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/stat.h> |
| 30 | #include <linux/fcntl.h> |
Hugh Dickins | ba92a43 | 2008-07-25 01:45:43 -0700 | [diff] [blame] | 31 | #include <linux/swap.h> |
Neil Horman | 74aadce | 2007-10-16 23:26:35 -0700 | [diff] [blame] | 32 | #include <linux/string.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #include <linux/init.h> |
Hugh Dickins | ca5b172 | 2008-07-28 15:46:18 -0700 | [diff] [blame] | 34 | #include <linux/pagemap.h> |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 35 | #include <linux/perf_event.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #include <linux/highmem.h> |
| 37 | #include <linux/spinlock.h> |
| 38 | #include <linux/key.h> |
| 39 | #include <linux/personality.h> |
| 40 | #include <linux/binfmts.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | #include <linux/utsname.h> |
Sukadev Bhattiprolu | 84d7378 | 2006-12-08 02:38:01 -0800 | [diff] [blame] | 42 | #include <linux/pid_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | #include <linux/module.h> |
| 44 | #include <linux/namei.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | #include <linux/mount.h> |
| 46 | #include <linux/security.h> |
| 47 | #include <linux/syscalls.h> |
Jay Lan | 8f0ab51 | 2006-09-30 23:28:59 -0700 | [diff] [blame] | 48 | #include <linux/tsacct_kern.h> |
Matt Helsley | 9f46080 | 2005-11-07 00:59:16 -0800 | [diff] [blame] | 49 | #include <linux/cn_proc.h> |
Al Viro | 473ae30 | 2006-04-26 14:04:08 -0400 | [diff] [blame] | 50 | #include <linux/audit.h> |
Roland McGrath | 6341c39 | 2008-07-25 19:45:44 -0700 | [diff] [blame] | 51 | #include <linux/tracehook.h> |
Johannes Berg | 5f4123b | 2008-07-09 10:28:40 +0200 | [diff] [blame] | 52 | #include <linux/kmod.h> |
Eric Paris | 6110e3a | 2008-12-17 13:53:20 -0500 | [diff] [blame] | 53 | #include <linux/fsnotify.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 54 | #include <linux/fs_struct.h> |
Neil Horman | 61be228 | 2009-09-23 15:56:58 -0700 | [diff] [blame] | 55 | #include <linux/pipe_fs_i.h> |
Ying Han | 3d5992d | 2010-10-26 14:21:23 -0700 | [diff] [blame] | 56 | #include <linux/oom.h> |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 57 | #include <linux/compat.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | |
| 59 | #include <asm/uaccess.h> |
| 60 | #include <asm/mmu_context.h> |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 61 | #include <asm/tlb.h> |
KAMEZAWA Hiroyuki | 43d2b11 | 2012-01-10 15:08:09 -0800 | [diff] [blame] | 62 | |
| 63 | #include <trace/events/task.h> |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 64 | #include "internal.h" |
Alex Kelly | 179899f | 2012-10-04 17:15:24 -0700 | [diff] [blame] | 65 | #include "coredump.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
David Smith | 4ff16c2 | 2012-02-07 10:11:05 -0600 | [diff] [blame] | 67 | #include <trace/events/sched.h> |
| 68 | |
Alan Cox | d6e7114 | 2005-06-23 00:09:43 -0700 | [diff] [blame] | 69 | int suid_dumpable = 0; |
| 70 | |
Alexey Dobriyan | e4dc1b1 | 2007-10-16 23:26:03 -0700 | [diff] [blame] | 71 | static LIST_HEAD(formats); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | static DEFINE_RWLOCK(binfmt_lock); |
| 73 | |
Al Viro | 8fc3dc5 | 2012-03-17 03:05:16 -0400 | [diff] [blame] | 74 | void __register_binfmt(struct linux_binfmt * fmt, int insert) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | { |
Al Viro | 8fc3dc5 | 2012-03-17 03:05:16 -0400 | [diff] [blame] | 76 | BUG_ON(!fmt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | write_lock(&binfmt_lock); |
Ivan Kokshaysky | 74641f5 | 2009-04-30 15:08:49 -0700 | [diff] [blame] | 78 | insert ? list_add(&fmt->lh, &formats) : |
| 79 | list_add_tail(&fmt->lh, &formats); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | write_unlock(&binfmt_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | } |
| 82 | |
Ivan Kokshaysky | 74641f5 | 2009-04-30 15:08:49 -0700 | [diff] [blame] | 83 | EXPORT_SYMBOL(__register_binfmt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
Alexey Dobriyan | f6b450d | 2007-10-16 23:26:04 -0700 | [diff] [blame] | 85 | void unregister_binfmt(struct linux_binfmt * fmt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | write_lock(&binfmt_lock); |
Alexey Dobriyan | e4dc1b1 | 2007-10-16 23:26:03 -0700 | [diff] [blame] | 88 | list_del(&fmt->lh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | write_unlock(&binfmt_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | } |
| 91 | |
| 92 | EXPORT_SYMBOL(unregister_binfmt); |
| 93 | |
| 94 | static inline void put_binfmt(struct linux_binfmt * fmt) |
| 95 | { |
| 96 | module_put(fmt->module); |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * Note that a shared library must be both readable and executable due to |
| 101 | * security reasons. |
| 102 | * |
| 103 | * Also note that we take the address to load from from the file itself. |
| 104 | */ |
Heiko Carstens | 1e7bfb2 | 2009-01-14 14:14:29 +0100 | [diff] [blame] | 105 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | { |
Al Viro | 964bd18 | 2008-07-26 03:33:14 -0400 | [diff] [blame] | 107 | struct file *file; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 108 | struct filename *tmp = getname(library); |
Al Viro | 964bd18 | 2008-07-26 03:33:14 -0400 | [diff] [blame] | 109 | int error = PTR_ERR(tmp); |
Al Viro | 47c805d | 2011-02-23 17:44:09 -0500 | [diff] [blame] | 110 | static const struct open_flags uselib_flags = { |
| 111 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
| 112 | .acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN, |
| 113 | .intent = LOOKUP_OPEN |
| 114 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 116 | if (IS_ERR(tmp)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | goto out; |
| 118 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 119 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW); |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 120 | putname(tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | error = PTR_ERR(file); |
| 122 | if (IS_ERR(file)) |
| 123 | goto out; |
| 124 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 125 | error = -EINVAL; |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 126 | if (!S_ISREG(file_inode(file)->i_mode)) |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 127 | goto exit; |
| 128 | |
| 129 | error = -EACCES; |
| 130 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
| 131 | goto exit; |
| 132 | |
Eric Paris | 2a12a9d | 2009-12-17 21:24:21 -0500 | [diff] [blame] | 133 | fsnotify_open(file); |
Eric Paris | 6110e3a | 2008-12-17 13:53:20 -0500 | [diff] [blame] | 134 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | error = -ENOEXEC; |
| 136 | if(file->f_op) { |
| 137 | struct linux_binfmt * fmt; |
| 138 | |
| 139 | read_lock(&binfmt_lock); |
Alexey Dobriyan | e4dc1b1 | 2007-10-16 23:26:03 -0700 | [diff] [blame] | 140 | list_for_each_entry(fmt, &formats, lh) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | if (!fmt->load_shlib) |
| 142 | continue; |
| 143 | if (!try_module_get(fmt->module)) |
| 144 | continue; |
| 145 | read_unlock(&binfmt_lock); |
| 146 | error = fmt->load_shlib(file); |
| 147 | read_lock(&binfmt_lock); |
| 148 | put_binfmt(fmt); |
| 149 | if (error != -ENOEXEC) |
| 150 | break; |
| 151 | } |
| 152 | read_unlock(&binfmt_lock); |
| 153 | } |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 154 | exit: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | fput(file); |
| 156 | out: |
| 157 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | } |
| 159 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 160 | #ifdef CONFIG_MMU |
Oleg Nesterov | ae6b585 | 2011-03-06 18:03:11 +0100 | [diff] [blame] | 161 | /* |
| 162 | * The nascent bprm->mm is not visible until exec_mmap() but it can |
| 163 | * use a lot of memory, account these pages in current->mm temporary |
| 164 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we |
| 165 | * change the counter back via acct_arg_size(0). |
| 166 | */ |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 167 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 168 | { |
| 169 | struct mm_struct *mm = current->mm; |
| 170 | long diff = (long)(pages - bprm->vma_pages); |
| 171 | |
| 172 | if (!mm || !diff) |
| 173 | return; |
| 174 | |
| 175 | bprm->vma_pages = pages; |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 176 | add_mm_counter(mm, MM_ANONPAGES, diff); |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 177 | } |
| 178 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 179 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 180 | int write) |
| 181 | { |
| 182 | struct page *page; |
| 183 | int ret; |
| 184 | |
| 185 | #ifdef CONFIG_STACK_GROWSUP |
| 186 | if (write) { |
Michal Hocko | d05f316 | 2011-05-24 17:11:44 -0700 | [diff] [blame] | 187 | ret = expand_downwards(bprm->vma, pos); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 188 | if (ret < 0) |
| 189 | return NULL; |
| 190 | } |
| 191 | #endif |
| 192 | ret = get_user_pages(current, bprm->mm, pos, |
| 193 | 1, write, 1, &page, NULL); |
| 194 | if (ret <= 0) |
| 195 | return NULL; |
| 196 | |
| 197 | if (write) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 198 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
Linus Torvalds | a64e715 | 2008-03-03 10:12:14 -0800 | [diff] [blame] | 199 | struct rlimit *rlim; |
| 200 | |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 201 | acct_arg_size(bprm, size / PAGE_SIZE); |
| 202 | |
Linus Torvalds | a64e715 | 2008-03-03 10:12:14 -0800 | [diff] [blame] | 203 | /* |
| 204 | * We've historically supported up to 32 pages (ARG_MAX) |
| 205 | * of argument strings even with small stacks |
| 206 | */ |
| 207 | if (size <= ARG_MAX) |
| 208 | return page; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 209 | |
| 210 | /* |
| 211 | * Limit to 1/4-th the stack size for the argv+env strings. |
| 212 | * This ensures that: |
| 213 | * - the remaining binfmt code will not run out of stack space, |
| 214 | * - the program will have a reasonable amount of stack left |
| 215 | * to work from. |
| 216 | */ |
Linus Torvalds | a64e715 | 2008-03-03 10:12:14 -0800 | [diff] [blame] | 217 | rlim = current->signal->rlim; |
Jiri Slaby | d554ed89 | 2010-03-05 13:42:42 -0800 | [diff] [blame] | 218 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 219 | put_page(page); |
| 220 | return NULL; |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | return page; |
| 225 | } |
| 226 | |
| 227 | static void put_arg_page(struct page *page) |
| 228 | { |
| 229 | put_page(page); |
| 230 | } |
| 231 | |
| 232 | static void free_arg_page(struct linux_binprm *bprm, int i) |
| 233 | { |
| 234 | } |
| 235 | |
| 236 | static void free_arg_pages(struct linux_binprm *bprm) |
| 237 | { |
| 238 | } |
| 239 | |
| 240 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| 241 | struct page *page) |
| 242 | { |
| 243 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); |
| 244 | } |
| 245 | |
| 246 | static int __bprm_mm_init(struct linux_binprm *bprm) |
| 247 | { |
Luiz Fernando N. Capitulino | eaccbfa | 2009-01-06 14:40:44 -0800 | [diff] [blame] | 248 | int err; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 249 | struct vm_area_struct *vma = NULL; |
| 250 | struct mm_struct *mm = bprm->mm; |
| 251 | |
| 252 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
| 253 | if (!vma) |
Luiz Fernando N. Capitulino | eaccbfa | 2009-01-06 14:40:44 -0800 | [diff] [blame] | 254 | return -ENOMEM; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 255 | |
| 256 | down_write(&mm->mmap_sem); |
| 257 | vma->vm_mm = mm; |
| 258 | |
| 259 | /* |
| 260 | * Place the stack at the largest stack address the architecture |
| 261 | * supports. Later, we'll move this to an appropriate place. We don't |
| 262 | * use STACK_TOP because that can depend on attributes which aren't |
| 263 | * configured yet. |
| 264 | */ |
Michal Hocko | aacb3d1 | 2011-07-26 16:08:40 -0700 | [diff] [blame] | 265 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 266 | vma->vm_end = STACK_TOP_MAX; |
| 267 | vma->vm_start = vma->vm_end - PAGE_SIZE; |
Mel Gorman | a8bef8ff | 2010-05-24 14:32:24 -0700 | [diff] [blame] | 268 | vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 269 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 270 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
Tavis Ormandy | 462e635e | 2010-12-09 15:29:42 +0100 | [diff] [blame] | 271 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 272 | err = insert_vm_struct(mm, vma); |
Luiz Fernando N. Capitulino | eaccbfa | 2009-01-06 14:40:44 -0800 | [diff] [blame] | 273 | if (err) |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 274 | goto err; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 275 | |
| 276 | mm->stack_vm = mm->total_vm = 1; |
| 277 | up_write(&mm->mmap_sem); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 278 | bprm->p = vma->vm_end - sizeof(void *); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 279 | return 0; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 280 | err: |
Luiz Fernando N. Capitulino | eaccbfa | 2009-01-06 14:40:44 -0800 | [diff] [blame] | 281 | up_write(&mm->mmap_sem); |
| 282 | bprm->vma = NULL; |
| 283 | kmem_cache_free(vm_area_cachep, vma); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 284 | return err; |
| 285 | } |
| 286 | |
| 287 | static bool valid_arg_len(struct linux_binprm *bprm, long len) |
| 288 | { |
| 289 | return len <= MAX_ARG_STRLEN; |
| 290 | } |
| 291 | |
| 292 | #else |
| 293 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 294 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 295 | { |
| 296 | } |
| 297 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 298 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 299 | int write) |
| 300 | { |
| 301 | struct page *page; |
| 302 | |
| 303 | page = bprm->page[pos / PAGE_SIZE]; |
| 304 | if (!page && write) { |
| 305 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); |
| 306 | if (!page) |
| 307 | return NULL; |
| 308 | bprm->page[pos / PAGE_SIZE] = page; |
| 309 | } |
| 310 | |
| 311 | return page; |
| 312 | } |
| 313 | |
| 314 | static void put_arg_page(struct page *page) |
| 315 | { |
| 316 | } |
| 317 | |
| 318 | static void free_arg_page(struct linux_binprm *bprm, int i) |
| 319 | { |
| 320 | if (bprm->page[i]) { |
| 321 | __free_page(bprm->page[i]); |
| 322 | bprm->page[i] = NULL; |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | static void free_arg_pages(struct linux_binprm *bprm) |
| 327 | { |
| 328 | int i; |
| 329 | |
| 330 | for (i = 0; i < MAX_ARG_PAGES; i++) |
| 331 | free_arg_page(bprm, i); |
| 332 | } |
| 333 | |
| 334 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| 335 | struct page *page) |
| 336 | { |
| 337 | } |
| 338 | |
| 339 | static int __bprm_mm_init(struct linux_binprm *bprm) |
| 340 | { |
| 341 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); |
| 342 | return 0; |
| 343 | } |
| 344 | |
| 345 | static bool valid_arg_len(struct linux_binprm *bprm, long len) |
| 346 | { |
| 347 | return len <= bprm->p; |
| 348 | } |
| 349 | |
| 350 | #endif /* CONFIG_MMU */ |
| 351 | |
| 352 | /* |
| 353 | * Create a new mm_struct and populate it with a temporary stack |
| 354 | * vm_area_struct. We don't have enough context at this point to set the stack |
| 355 | * flags, permissions, and offset, so we use temporary values. We'll update |
| 356 | * them later in setup_arg_pages(). |
| 357 | */ |
Yuanhan Liu | 9cc64ce | 2013-02-20 13:16:01 +1100 | [diff] [blame] | 358 | static int bprm_mm_init(struct linux_binprm *bprm) |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 359 | { |
| 360 | int err; |
| 361 | struct mm_struct *mm = NULL; |
| 362 | |
| 363 | bprm->mm = mm = mm_alloc(); |
| 364 | err = -ENOMEM; |
| 365 | if (!mm) |
| 366 | goto err; |
| 367 | |
| 368 | err = init_new_context(current, mm); |
| 369 | if (err) |
| 370 | goto err; |
| 371 | |
| 372 | err = __bprm_mm_init(bprm); |
| 373 | if (err) |
| 374 | goto err; |
| 375 | |
| 376 | return 0; |
| 377 | |
| 378 | err: |
| 379 | if (mm) { |
| 380 | bprm->mm = NULL; |
| 381 | mmdrop(mm); |
| 382 | } |
| 383 | |
| 384 | return err; |
| 385 | } |
| 386 | |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 387 | struct user_arg_ptr { |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 388 | #ifdef CONFIG_COMPAT |
| 389 | bool is_compat; |
| 390 | #endif |
| 391 | union { |
| 392 | const char __user *const __user *native; |
| 393 | #ifdef CONFIG_COMPAT |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 394 | const compat_uptr_t __user *compat; |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 395 | #endif |
| 396 | } ptr; |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 397 | }; |
| 398 | |
| 399 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 400 | { |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 401 | const char __user *native; |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 402 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 403 | #ifdef CONFIG_COMPAT |
| 404 | if (unlikely(argv.is_compat)) { |
| 405 | compat_uptr_t compat; |
| 406 | |
| 407 | if (get_user(compat, argv.ptr.compat + nr)) |
| 408 | return ERR_PTR(-EFAULT); |
| 409 | |
| 410 | return compat_ptr(compat); |
| 411 | } |
| 412 | #endif |
| 413 | |
| 414 | if (get_user(native, argv.ptr.native + nr)) |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 415 | return ERR_PTR(-EFAULT); |
| 416 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 417 | return native; |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 418 | } |
| 419 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | /* |
| 421 | * count() counts the number of strings in array ARGV. |
| 422 | */ |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 423 | static int count(struct user_arg_ptr argv, int max) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 424 | { |
| 425 | int i = 0; |
| 426 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 427 | if (argv.ptr.native != NULL) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | for (;;) { |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 429 | const char __user *p = get_user_arg_ptr(argv, i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | if (!p) |
| 432 | break; |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 433 | |
| 434 | if (IS_ERR(p)) |
| 435 | return -EFAULT; |
| 436 | |
Xi Wang | 6d92d4f | 2013-01-11 14:31:48 -0800 | [diff] [blame] | 437 | if (i >= max) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 438 | return -E2BIG; |
Xi Wang | 6d92d4f | 2013-01-11 14:31:48 -0800 | [diff] [blame] | 439 | ++i; |
Roland McGrath | 9aea5a6 | 2010-09-07 19:37:06 -0700 | [diff] [blame] | 440 | |
| 441 | if (fatal_signal_pending(current)) |
| 442 | return -ERESTARTNOHAND; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | cond_resched(); |
| 444 | } |
| 445 | } |
| 446 | return i; |
| 447 | } |
| 448 | |
| 449 | /* |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 450 | * 'copy_strings()' copies argument/environment strings from the old |
| 451 | * processes's memory to the new process's stack. The call to get_user_pages() |
| 452 | * ensures the destination page is created and not swapped out. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | */ |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 454 | static int copy_strings(int argc, struct user_arg_ptr argv, |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 455 | struct linux_binprm *bprm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | { |
| 457 | struct page *kmapped_page = NULL; |
| 458 | char *kaddr = NULL; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 459 | unsigned long kpos = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | int ret; |
| 461 | |
| 462 | while (argc-- > 0) { |
David Howells | d762746 | 2010-08-17 23:52:56 +0100 | [diff] [blame] | 463 | const char __user *str; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | int len; |
| 465 | unsigned long pos; |
| 466 | |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 467 | ret = -EFAULT; |
| 468 | str = get_user_arg_ptr(argv, argc); |
| 469 | if (IS_ERR(str)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 472 | len = strnlen_user(str, MAX_ARG_STRLEN); |
| 473 | if (!len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | goto out; |
Oleg Nesterov | 1d1dbf8 | 2011-03-06 18:02:21 +0100 | [diff] [blame] | 475 | |
| 476 | ret = -E2BIG; |
| 477 | if (!valid_arg_len(bprm, len)) |
| 478 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 480 | /* We're going to work our way backwords. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | pos = bprm->p; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 482 | str += len; |
| 483 | bprm->p -= len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | |
| 485 | while (len > 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 486 | int offset, bytes_to_copy; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | |
Roland McGrath | 9aea5a6 | 2010-09-07 19:37:06 -0700 | [diff] [blame] | 488 | if (fatal_signal_pending(current)) { |
| 489 | ret = -ERESTARTNOHAND; |
| 490 | goto out; |
| 491 | } |
Roland McGrath | 7993bc1 | 2010-09-07 19:36:28 -0700 | [diff] [blame] | 492 | cond_resched(); |
| 493 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | offset = pos % PAGE_SIZE; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 495 | if (offset == 0) |
| 496 | offset = PAGE_SIZE; |
| 497 | |
| 498 | bytes_to_copy = offset; |
| 499 | if (bytes_to_copy > len) |
| 500 | bytes_to_copy = len; |
| 501 | |
| 502 | offset -= bytes_to_copy; |
| 503 | pos -= bytes_to_copy; |
| 504 | str -= bytes_to_copy; |
| 505 | len -= bytes_to_copy; |
| 506 | |
| 507 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { |
| 508 | struct page *page; |
| 509 | |
| 510 | page = get_arg_page(bprm, pos, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | if (!page) { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 512 | ret = -E2BIG; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | goto out; |
| 514 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 516 | if (kmapped_page) { |
| 517 | flush_kernel_dcache_page(kmapped_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | kunmap(kmapped_page); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 519 | put_arg_page(kmapped_page); |
| 520 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | kmapped_page = page; |
| 522 | kaddr = kmap(kmapped_page); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 523 | kpos = pos & PAGE_MASK; |
| 524 | flush_arg_page(bprm, kpos, kmapped_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | } |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 526 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | ret = -EFAULT; |
| 528 | goto out; |
| 529 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | } |
| 531 | } |
| 532 | ret = 0; |
| 533 | out: |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 534 | if (kmapped_page) { |
| 535 | flush_kernel_dcache_page(kmapped_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | kunmap(kmapped_page); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 537 | put_arg_page(kmapped_page); |
| 538 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | return ret; |
| 540 | } |
| 541 | |
| 542 | /* |
| 543 | * Like copy_strings, but get argv and its values from kernel memory. |
| 544 | */ |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 545 | int copy_strings_kernel(int argc, const char *const *__argv, |
David Howells | d762746 | 2010-08-17 23:52:56 +0100 | [diff] [blame] | 546 | struct linux_binprm *bprm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | { |
| 548 | int r; |
| 549 | mm_segment_t oldfs = get_fs(); |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 550 | struct user_arg_ptr argv = { |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 551 | .ptr.native = (const char __user *const __user *)__argv, |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 552 | }; |
| 553 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 554 | set_fs(KERNEL_DS); |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 555 | r = copy_strings(argc, argv, bprm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | set_fs(oldfs); |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 557 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | return r; |
| 559 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | EXPORT_SYMBOL(copy_strings_kernel); |
| 561 | |
| 562 | #ifdef CONFIG_MMU |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 563 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | /* |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 565 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
| 566 | * the binfmt code determines where the new stack should reside, we shift it to |
| 567 | * its final location. The process proceeds as follows: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | * |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 569 | * 1) Use shift to calculate the new vma endpoints. |
| 570 | * 2) Extend vma to cover both the old and new ranges. This ensures the |
| 571 | * arguments passed to subsequent functions are consistent. |
| 572 | * 3) Move vma's page tables to the new range. |
| 573 | * 4) Free up any cleared pgd range. |
| 574 | * 5) Shrink the vma to cover only the new range. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | */ |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 576 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | { |
| 578 | struct mm_struct *mm = vma->vm_mm; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 579 | unsigned long old_start = vma->vm_start; |
| 580 | unsigned long old_end = vma->vm_end; |
| 581 | unsigned long length = old_end - old_start; |
| 582 | unsigned long new_start = old_start - shift; |
| 583 | unsigned long new_end = old_end - shift; |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 584 | struct mmu_gather tlb; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 586 | BUG_ON(new_start > new_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 588 | /* |
| 589 | * ensure there are no vmas between where we want to go |
| 590 | * and where we are |
| 591 | */ |
| 592 | if (vma != find_vma(mm, new_start)) |
| 593 | return -EFAULT; |
| 594 | |
| 595 | /* |
| 596 | * cover the whole range: [new_start, old_end) |
| 597 | */ |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 598 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
| 599 | return -ENOMEM; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 600 | |
| 601 | /* |
| 602 | * move the page tables downwards, on failure we rely on |
| 603 | * process cleanup to remove whatever mess we made. |
| 604 | */ |
| 605 | if (length != move_page_tables(vma, old_start, |
Michel Lespinasse | 38a7601 | 2012-10-08 16:31:50 -0700 | [diff] [blame] | 606 | vma, new_start, length, false)) |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 607 | return -ENOMEM; |
| 608 | |
| 609 | lru_add_drain(); |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 610 | tlb_gather_mmu(&tlb, mm, 0); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 611 | if (new_end > old_start) { |
| 612 | /* |
| 613 | * when the old and new regions overlap clear from new_end. |
| 614 | */ |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 615 | free_pgd_range(&tlb, new_end, old_end, new_end, |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 616 | vma->vm_next ? vma->vm_next->vm_start : 0); |
| 617 | } else { |
| 618 | /* |
| 619 | * otherwise, clean from old_start; this is done to not touch |
| 620 | * the address space in [new_end, old_start) some architectures |
| 621 | * have constraints on va-space that make this illegal (IA64) - |
| 622 | * for the others its just a little faster. |
| 623 | */ |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 624 | free_pgd_range(&tlb, old_start, old_end, new_end, |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 625 | vma->vm_next ? vma->vm_next->vm_start : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | } |
Peter Zijlstra | d16dfc5 | 2011-05-24 17:11:45 -0700 | [diff] [blame] | 627 | tlb_finish_mmu(&tlb, new_end, old_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 629 | /* |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 630 | * Shrink the vma to just the new range. Always succeeds. |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 631 | */ |
| 632 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); |
| 633 | |
| 634 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | } |
| 636 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 637 | /* |
| 638 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, |
| 639 | * the stack is optionally relocated, and some extra space is added. |
| 640 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 641 | int setup_arg_pages(struct linux_binprm *bprm, |
| 642 | unsigned long stack_top, |
| 643 | int executable_stack) |
| 644 | { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 645 | unsigned long ret; |
| 646 | unsigned long stack_shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | struct mm_struct *mm = current->mm; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 648 | struct vm_area_struct *vma = bprm->vma; |
| 649 | struct vm_area_struct *prev = NULL; |
| 650 | unsigned long vm_flags; |
| 651 | unsigned long stack_base; |
Michael Neuling | 803bf5e | 2010-02-10 13:56:42 -0800 | [diff] [blame] | 652 | unsigned long stack_size; |
| 653 | unsigned long stack_expand; |
| 654 | unsigned long rlim_stack; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | |
| 656 | #ifdef CONFIG_STACK_GROWSUP |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | /* Limit stack size to 1GB */ |
Jiri Slaby | d554ed89 | 2010-03-05 13:42:42 -0800 | [diff] [blame] | 658 | stack_base = rlimit_max(RLIMIT_STACK); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | if (stack_base > (1 << 30)) |
| 660 | stack_base = 1 << 30; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 662 | /* Make sure we didn't let the argument array grow too large. */ |
| 663 | if (vma->vm_end - vma->vm_start > stack_base) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | return -ENOMEM; |
| 665 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 666 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
| 667 | |
| 668 | stack_shift = vma->vm_start - stack_base; |
| 669 | mm->arg_start = bprm->p - stack_shift; |
| 670 | bprm->p = vma->vm_end - stack_shift; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | #else |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 672 | stack_top = arch_align_stack(stack_top); |
| 673 | stack_top = PAGE_ALIGN(stack_top); |
Roland McGrath | 1b52818 | 2010-09-07 19:35:49 -0700 | [diff] [blame] | 674 | |
| 675 | if (unlikely(stack_top < mmap_min_addr) || |
| 676 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) |
| 677 | return -ENOMEM; |
| 678 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 679 | stack_shift = vma->vm_end - stack_top; |
| 680 | |
| 681 | bprm->p -= stack_shift; |
| 682 | mm->arg_start = bprm->p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | #endif |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 684 | |
| 685 | if (bprm->loader) |
| 686 | bprm->loader -= stack_shift; |
| 687 | bprm->exec -= stack_shift; |
| 688 | |
| 689 | down_write(&mm->mmap_sem); |
Hugh Dickins | 96a8e13 | 2008-07-10 21:19:20 +0100 | [diff] [blame] | 690 | vm_flags = VM_STACK_FLAGS; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 691 | |
| 692 | /* |
| 693 | * Adjust stack execute permissions; explicitly enable for |
| 694 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone |
| 695 | * (arch default) otherwise. |
| 696 | */ |
| 697 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) |
| 698 | vm_flags |= VM_EXEC; |
| 699 | else if (executable_stack == EXSTACK_DISABLE_X) |
| 700 | vm_flags &= ~VM_EXEC; |
| 701 | vm_flags |= mm->def_flags; |
Mel Gorman | a8bef8ff | 2010-05-24 14:32:24 -0700 | [diff] [blame] | 702 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 703 | |
| 704 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, |
| 705 | vm_flags); |
| 706 | if (ret) |
| 707 | goto out_unlock; |
| 708 | BUG_ON(prev != vma); |
| 709 | |
| 710 | /* Move stack pages down in memory. */ |
| 711 | if (stack_shift) { |
| 712 | ret = shift_arg_pages(vma, stack_shift); |
Anton Blanchard | fc63cf2 | 2009-11-11 14:26:48 -0800 | [diff] [blame] | 713 | if (ret) |
| 714 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | } |
| 716 | |
Mel Gorman | a8bef8ff | 2010-05-24 14:32:24 -0700 | [diff] [blame] | 717 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
| 718 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; |
| 719 | |
Michael Neuling | 5ef097d | 2010-03-05 13:42:57 -0800 | [diff] [blame] | 720 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
Michael Neuling | 803bf5e | 2010-02-10 13:56:42 -0800 | [diff] [blame] | 721 | stack_size = vma->vm_end - vma->vm_start; |
| 722 | /* |
| 723 | * Align this down to a page boundary as expand_stack |
| 724 | * will align it up. |
| 725 | */ |
| 726 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 727 | #ifdef CONFIG_STACK_GROWSUP |
Michael Neuling | 803bf5e | 2010-02-10 13:56:42 -0800 | [diff] [blame] | 728 | if (stack_size + stack_expand > rlim_stack) |
| 729 | stack_base = vma->vm_start + rlim_stack; |
| 730 | else |
| 731 | stack_base = vma->vm_end + stack_expand; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 732 | #else |
Michael Neuling | 803bf5e | 2010-02-10 13:56:42 -0800 | [diff] [blame] | 733 | if (stack_size + stack_expand > rlim_stack) |
| 734 | stack_base = vma->vm_end - rlim_stack; |
| 735 | else |
| 736 | stack_base = vma->vm_start - stack_expand; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 737 | #endif |
Eric B Munson | 3af9e85 | 2010-05-18 15:30:49 +0100 | [diff] [blame] | 738 | current->mm->start_stack = bprm->p; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 739 | ret = expand_stack(vma, stack_base); |
| 740 | if (ret) |
| 741 | ret = -EFAULT; |
| 742 | |
| 743 | out_unlock: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | up_write(&mm->mmap_sem); |
Anton Blanchard | fc63cf2 | 2009-11-11 14:26:48 -0800 | [diff] [blame] | 745 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 747 | EXPORT_SYMBOL(setup_arg_pages); |
| 748 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 749 | #endif /* CONFIG_MMU */ |
| 750 | |
| 751 | struct file *open_exec(const char *name) |
| 752 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | struct file *file; |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 754 | int err; |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 755 | struct filename tmp = { .name = name }; |
Al Viro | 47c805d | 2011-02-23 17:44:09 -0500 | [diff] [blame] | 756 | static const struct open_flags open_exec_flags = { |
| 757 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
| 758 | .acc_mode = MAY_EXEC | MAY_OPEN, |
| 759 | .intent = LOOKUP_OPEN |
| 760 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 761 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 762 | file = do_filp_open(AT_FDCWD, &tmp, &open_exec_flags, LOOKUP_FOLLOW); |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 763 | if (IS_ERR(file)) |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 764 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 766 | err = -EACCES; |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 767 | if (!S_ISREG(file_inode(file)->i_mode)) |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 768 | goto exit; |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 769 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 770 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
| 771 | goto exit; |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 772 | |
Eric Paris | 2a12a9d | 2009-12-17 21:24:21 -0500 | [diff] [blame] | 773 | fsnotify_open(file); |
Eric Paris | 6110e3a | 2008-12-17 13:53:20 -0500 | [diff] [blame] | 774 | |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 775 | err = deny_write_access(file); |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 776 | if (err) |
| 777 | goto exit; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 779 | out: |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 780 | return file; |
| 781 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 782 | exit: |
| 783 | fput(file); |
Christoph Hellwig | e56b6a5 | 2008-05-19 07:53:34 +0200 | [diff] [blame] | 784 | return ERR_PTR(err); |
| 785 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | EXPORT_SYMBOL(open_exec); |
| 787 | |
Mimi Zohar | 6777d77 | 2009-08-21 14:32:48 -0400 | [diff] [blame] | 788 | int kernel_read(struct file *file, loff_t offset, |
| 789 | char *addr, unsigned long count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | { |
| 791 | mm_segment_t old_fs; |
| 792 | loff_t pos = offset; |
| 793 | int result; |
| 794 | |
| 795 | old_fs = get_fs(); |
| 796 | set_fs(get_ds()); |
| 797 | /* The cast to a user pointer is valid due to the set_fs() */ |
| 798 | result = vfs_read(file, (void __user *)addr, count, &pos); |
| 799 | set_fs(old_fs); |
| 800 | return result; |
| 801 | } |
| 802 | |
| 803 | EXPORT_SYMBOL(kernel_read); |
| 804 | |
| 805 | static int exec_mmap(struct mm_struct *mm) |
| 806 | { |
| 807 | struct task_struct *tsk; |
| 808 | struct mm_struct * old_mm, *active_mm; |
| 809 | |
| 810 | /* Notify parent that we're no longer interested in the old VM */ |
| 811 | tsk = current; |
| 812 | old_mm = current->mm; |
| 813 | mm_release(tsk, old_mm); |
| 814 | |
| 815 | if (old_mm) { |
Konstantin Khlebnikov | 4fe7efd | 2012-06-20 12:53:01 -0700 | [diff] [blame] | 816 | sync_mm_rss(old_mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | /* |
| 818 | * Make sure that if there is a core dump in progress |
| 819 | * for the old mm, we get out and die instead of going |
| 820 | * through with the exec. We must hold mmap_sem around |
Oleg Nesterov | 999d9fc | 2008-07-25 01:47:41 -0700 | [diff] [blame] | 821 | * checking core_state and changing tsk->mm. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 822 | */ |
| 823 | down_read(&old_mm->mmap_sem); |
Oleg Nesterov | 999d9fc | 2008-07-25 01:47:41 -0700 | [diff] [blame] | 824 | if (unlikely(old_mm->core_state)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 825 | up_read(&old_mm->mmap_sem); |
| 826 | return -EINTR; |
| 827 | } |
| 828 | } |
| 829 | task_lock(tsk); |
| 830 | active_mm = tsk->active_mm; |
| 831 | tsk->mm = mm; |
| 832 | tsk->active_mm = mm; |
| 833 | activate_mm(active_mm, mm); |
| 834 | task_unlock(tsk); |
| 835 | arch_pick_mmap_layout(mm); |
| 836 | if (old_mm) { |
| 837 | up_read(&old_mm->mmap_sem); |
Eric Sesterhenn | 7dddb12 | 2006-04-01 01:13:38 +0200 | [diff] [blame] | 838 | BUG_ON(active_mm != old_mm); |
Oleg Nesterov | 701085b | 2012-03-19 17:04:01 +0100 | [diff] [blame] | 839 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
Balbir Singh | 31a78f2 | 2008-09-28 23:09:31 +0100 | [diff] [blame] | 840 | mm_update_next_owner(old_mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 841 | mmput(old_mm); |
| 842 | return 0; |
| 843 | } |
| 844 | mmdrop(active_mm); |
| 845 | return 0; |
| 846 | } |
| 847 | |
| 848 | /* |
| 849 | * This function makes sure the current process has its own signal table, |
| 850 | * so that flush_signal_handlers can later reset the handlers without |
| 851 | * disturbing other processes. (Other processes might share the signal |
| 852 | * table via the CLONE_SIGHAND option to clone().) |
| 853 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 854 | static int de_thread(struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 855 | { |
| 856 | struct signal_struct *sig = tsk->signal; |
Oleg Nesterov | b2c903b | 2007-10-16 23:27:22 -0700 | [diff] [blame] | 857 | struct sighand_struct *oldsighand = tsk->sighand; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | spinlock_t *lock = &oldsighand->siglock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 860 | if (thread_group_empty(tsk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | goto no_thread_group; |
| 862 | |
| 863 | /* |
| 864 | * Kill all other threads in the thread group. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 865 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 866 | spin_lock_irq(lock); |
Oleg Nesterov | ed5d2ca | 2008-02-04 22:27:24 -0800 | [diff] [blame] | 867 | if (signal_group_exit(sig)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | /* |
| 869 | * Another group action in progress, just |
| 870 | * return so that the signal is processed. |
| 871 | */ |
| 872 | spin_unlock_irq(lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | return -EAGAIN; |
| 874 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | |
Oleg Nesterov | d344193 | 2010-05-26 14:43:11 -0700 | [diff] [blame] | 876 | sig->group_exit_task = tsk; |
| 877 | sig->notify_count = zap_other_threads(tsk); |
| 878 | if (!thread_group_leader(tsk)) |
| 879 | sig->notify_count--; |
| 880 | |
| 881 | while (sig->notify_count) { |
Oleg Nesterov | d5bbd43 | 2012-10-08 19:13:01 +0200 | [diff] [blame] | 882 | __set_current_state(TASK_KILLABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 883 | spin_unlock_irq(lock); |
| 884 | schedule(); |
Oleg Nesterov | d5bbd43 | 2012-10-08 19:13:01 +0200 | [diff] [blame] | 885 | if (unlikely(__fatal_signal_pending(tsk))) |
| 886 | goto killed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | spin_lock_irq(lock); |
| 888 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 889 | spin_unlock_irq(lock); |
| 890 | |
| 891 | /* |
| 892 | * At this point all other threads have exited, all we have to |
| 893 | * do is to wait for the thread group leader to become inactive, |
| 894 | * and to assume its PID: |
| 895 | */ |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 896 | if (!thread_group_leader(tsk)) { |
Oleg Nesterov | 8187926 | 2008-12-01 14:18:16 -0800 | [diff] [blame] | 897 | struct task_struct *leader = tsk->group_leader; |
Oleg Nesterov | 6db840f | 2007-10-16 23:27:23 -0700 | [diff] [blame] | 898 | |
Oleg Nesterov | 2800d8d | 2008-04-30 00:53:12 -0700 | [diff] [blame] | 899 | sig->notify_count = -1; /* for exit_notify() */ |
Oleg Nesterov | 6db840f | 2007-10-16 23:27:23 -0700 | [diff] [blame] | 900 | for (;;) { |
| 901 | write_lock_irq(&tasklist_lock); |
| 902 | if (likely(leader->exit_state)) |
| 903 | break; |
Oleg Nesterov | d5bbd43 | 2012-10-08 19:13:01 +0200 | [diff] [blame] | 904 | __set_current_state(TASK_KILLABLE); |
Oleg Nesterov | 6db840f | 2007-10-16 23:27:23 -0700 | [diff] [blame] | 905 | write_unlock_irq(&tasklist_lock); |
| 906 | schedule(); |
Oleg Nesterov | d5bbd43 | 2012-10-08 19:13:01 +0200 | [diff] [blame] | 907 | if (unlikely(__fatal_signal_pending(tsk))) |
| 908 | goto killed; |
Oleg Nesterov | 6db840f | 2007-10-16 23:27:23 -0700 | [diff] [blame] | 909 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 910 | |
Roland McGrath | f5e9028 | 2006-04-10 22:54:16 -0700 | [diff] [blame] | 911 | /* |
| 912 | * The only record we have of the real-time age of a |
| 913 | * process, regardless of execs it's done, is start_time. |
| 914 | * All the past CPU time is accumulated in signal_struct |
| 915 | * from sister threads now dead. But in this non-leader |
| 916 | * exec, nothing survives from the original leader thread, |
| 917 | * whose birth marks the true age of this process now. |
| 918 | * When we take on its identity by switching to its PID, we |
| 919 | * also take its birthdate (always earlier than our own). |
| 920 | */ |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 921 | tsk->start_time = leader->start_time; |
Roland McGrath | f5e9028 | 2006-04-10 22:54:16 -0700 | [diff] [blame] | 922 | |
Pavel Emelyanov | bac0abd | 2007-10-18 23:40:18 -0700 | [diff] [blame] | 923 | BUG_ON(!same_thread_group(leader, tsk)); |
| 924 | BUG_ON(has_group_leader_pid(tsk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | /* |
| 926 | * An exec() starts a new thread group with the |
| 927 | * TGID of the previous thread group. Rehash the |
| 928 | * two threads with a switched PID, and release |
| 929 | * the former thread group leader: |
| 930 | */ |
Eric W. Biederman | d73d652 | 2006-03-28 16:11:03 -0800 | [diff] [blame] | 931 | |
| 932 | /* Become a process group leader with the old leader's pid. |
Eric W. Biederman | c18258c | 2006-09-27 01:51:06 -0700 | [diff] [blame] | 933 | * The old leader becomes a thread of the this thread group. |
| 934 | * Note: The old leader also uses this pid until release_task |
Eric W. Biederman | d73d652 | 2006-03-28 16:11:03 -0800 | [diff] [blame] | 935 | * is called. Odd but simple and correct. |
| 936 | */ |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 937 | detach_pid(tsk, PIDTYPE_PID); |
| 938 | tsk->pid = leader->pid; |
Sukadev Bhattiprolu | 3743ca0 | 2007-10-18 23:39:51 -0700 | [diff] [blame] | 939 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 940 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
| 941 | transfer_pid(leader, tsk, PIDTYPE_SID); |
Oleg Nesterov | 9cd80bb | 2009-12-17 15:27:15 -0800 | [diff] [blame] | 942 | |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 943 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
Oleg Nesterov | 9cd80bb | 2009-12-17 15:27:15 -0800 | [diff] [blame] | 944 | list_replace_init(&leader->sibling, &tsk->sibling); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 946 | tsk->group_leader = tsk; |
| 947 | leader->group_leader = tsk; |
Eric W. Biederman | de12a78 | 2006-04-10 17:16:49 -0600 | [diff] [blame] | 948 | |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 949 | tsk->exit_signal = SIGCHLD; |
Oleg Nesterov | 087806b | 2011-06-22 23:10:26 +0200 | [diff] [blame] | 950 | leader->exit_signal = -1; |
Oleg Nesterov | 962b564 | 2005-11-23 13:37:43 -0800 | [diff] [blame] | 951 | |
| 952 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); |
| 953 | leader->exit_state = EXIT_DEAD; |
Oleg Nesterov | eac1b5e | 2011-07-21 20:00:43 +0200 | [diff] [blame] | 954 | |
| 955 | /* |
| 956 | * We are going to release_task()->ptrace_unlink() silently, |
| 957 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees |
| 958 | * the tracer wont't block again waiting for this thread. |
| 959 | */ |
| 960 | if (unlikely(leader->ptrace)) |
| 961 | __wake_up_parent(leader, leader->parent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 962 | write_unlock_irq(&tasklist_lock); |
Oleg Nesterov | 8187926 | 2008-12-01 14:18:16 -0800 | [diff] [blame] | 963 | |
| 964 | release_task(leader); |
Oleg Nesterov | ed5d2ca | 2008-02-04 22:27:24 -0800 | [diff] [blame] | 965 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | |
Oleg Nesterov | 6db840f | 2007-10-16 23:27:23 -0700 | [diff] [blame] | 967 | sig->group_exit_task = NULL; |
| 968 | sig->notify_count = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | |
| 970 | no_thread_group: |
Oleg Nesterov | e636825 | 2012-03-19 17:03:22 +0100 | [diff] [blame] | 971 | /* we have changed execution domain */ |
| 972 | tsk->exit_signal = SIGCHLD; |
| 973 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | exit_itimers(sig); |
Oleg Nesterov | cbaffba | 2008-05-26 20:55:42 +0400 | [diff] [blame] | 975 | flush_itimer_signals(); |
Oleg Nesterov | 329f7db | 2005-11-07 21:12:43 +0300 | [diff] [blame] | 976 | |
Oleg Nesterov | b2c903b | 2007-10-16 23:27:22 -0700 | [diff] [blame] | 977 | if (atomic_read(&oldsighand->count) != 1) { |
| 978 | struct sighand_struct *newsighand; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | /* |
Oleg Nesterov | b2c903b | 2007-10-16 23:27:22 -0700 | [diff] [blame] | 980 | * This ->sighand is shared with the CLONE_SIGHAND |
| 981 | * but not CLONE_THREAD task, switch to the new one. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 982 | */ |
Oleg Nesterov | b2c903b | 2007-10-16 23:27:22 -0700 | [diff] [blame] | 983 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
| 984 | if (!newsighand) |
| 985 | return -ENOMEM; |
| 986 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 987 | atomic_set(&newsighand->count, 1); |
| 988 | memcpy(newsighand->action, oldsighand->action, |
| 989 | sizeof(newsighand->action)); |
| 990 | |
| 991 | write_lock_irq(&tasklist_lock); |
| 992 | spin_lock(&oldsighand->siglock); |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 993 | rcu_assign_pointer(tsk->sighand, newsighand); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 994 | spin_unlock(&oldsighand->siglock); |
| 995 | write_unlock_irq(&tasklist_lock); |
| 996 | |
Davide Libenzi | fba2afa | 2007-05-10 22:23:13 -0700 | [diff] [blame] | 997 | __cleanup_sighand(oldsighand); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 998 | } |
| 999 | |
Eric W. Biederman | aafe6c2 | 2006-09-27 01:51:13 -0700 | [diff] [blame] | 1000 | BUG_ON(!thread_group_leader(tsk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | return 0; |
Oleg Nesterov | d5bbd43 | 2012-10-08 19:13:01 +0200 | [diff] [blame] | 1002 | |
| 1003 | killed: |
| 1004 | /* protects against exit_notify() and __exit_signal() */ |
| 1005 | read_lock(&tasklist_lock); |
| 1006 | sig->group_exit_task = NULL; |
| 1007 | sig->notify_count = 0; |
| 1008 | read_unlock(&tasklist_lock); |
| 1009 | return -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | } |
Oleg Nesterov | 0840a90 | 2007-10-16 23:27:22 -0700 | [diff] [blame] | 1011 | |
Andrew Morton | 59714d6 | 2008-02-04 22:27:21 -0800 | [diff] [blame] | 1012 | char *get_task_comm(char *buf, struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | { |
| 1014 | /* buf must be at least sizeof(tsk->comm) in size */ |
| 1015 | task_lock(tsk); |
| 1016 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); |
| 1017 | task_unlock(tsk); |
Andrew Morton | 59714d6 | 2008-02-04 22:27:21 -0800 | [diff] [blame] | 1018 | return buf; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1019 | } |
J Freyensee | 7d74f49 | 2011-05-06 16:56:47 -0700 | [diff] [blame] | 1020 | EXPORT_SYMBOL_GPL(get_task_comm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1021 | |
Al Viro | 6a6d27d | 2012-08-21 09:56:33 -0400 | [diff] [blame] | 1022 | /* |
| 1023 | * These functions flushes out all traces of the currently running executable |
| 1024 | * so that a new one can be started |
| 1025 | */ |
| 1026 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1027 | void set_task_comm(struct task_struct *tsk, char *buf) |
| 1028 | { |
| 1029 | task_lock(tsk); |
john stultz | 4614a696b | 2009-12-14 18:00:05 -0800 | [diff] [blame] | 1030 | |
KAMEZAWA Hiroyuki | 43d2b11 | 2012-01-10 15:08:09 -0800 | [diff] [blame] | 1031 | trace_task_rename(tsk, buf); |
| 1032 | |
john stultz | 4614a696b | 2009-12-14 18:00:05 -0800 | [diff] [blame] | 1033 | /* |
| 1034 | * Threads may access current->comm without holding |
| 1035 | * the task lock, so write the string carefully. |
| 1036 | * Readers without a lock may see incomplete new |
| 1037 | * names but are safe from non-terminating string reads. |
| 1038 | */ |
| 1039 | memset(tsk->comm, 0, TASK_COMM_LEN); |
| 1040 | wmb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
| 1042 | task_unlock(tsk); |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1043 | perf_event_comm(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | } |
| 1045 | |
Heiko Carstens | 96e02d1 | 2012-02-04 10:47:10 +0100 | [diff] [blame] | 1046 | static void filename_to_taskname(char *tcomm, const char *fn, unsigned int len) |
| 1047 | { |
| 1048 | int i, ch; |
| 1049 | |
| 1050 | /* Copies the binary name from after last slash */ |
| 1051 | for (i = 0; (ch = *(fn++)) != '\0';) { |
| 1052 | if (ch == '/') |
| 1053 | i = 0; /* overwrite what we wrote */ |
| 1054 | else |
| 1055 | if (i < len - 1) |
| 1056 | tcomm[i++] = ch; |
| 1057 | } |
| 1058 | tcomm[i] = '\0'; |
| 1059 | } |
| 1060 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | int flush_old_exec(struct linux_binprm * bprm) |
| 1062 | { |
Linus Torvalds | 221af7f | 2010-01-28 22:14:42 -0800 | [diff] [blame] | 1063 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1064 | |
| 1065 | /* |
| 1066 | * Make sure we have a private signal table and that |
| 1067 | * we are unassociated from the previous thread group. |
| 1068 | */ |
| 1069 | retval = de_thread(current); |
| 1070 | if (retval) |
| 1071 | goto out; |
| 1072 | |
Matt Helsley | 925d1c4 | 2008-04-29 01:01:36 -0700 | [diff] [blame] | 1073 | set_mm_exe_file(bprm->mm, bprm->file); |
| 1074 | |
Heiko Carstens | 96e02d1 | 2012-02-04 10:47:10 +0100 | [diff] [blame] | 1075 | filename_to_taskname(bprm->tcomm, bprm->filename, sizeof(bprm->tcomm)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1076 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1077 | * Release all of the old mmap stuff |
| 1078 | */ |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 1079 | acct_arg_size(bprm, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | retval = exec_mmap(bprm->mm); |
| 1081 | if (retval) |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 1082 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1083 | |
| 1084 | bprm->mm = NULL; /* We're using it now */ |
Linus Torvalds | 7ab02af | 2010-02-02 12:37:44 -0800 | [diff] [blame] | 1085 | |
Mathias Krause | dac853a | 2011-06-09 20:05:18 +0200 | [diff] [blame] | 1086 | set_fs(USER_DS); |
Oleg Nesterov | b40a795 | 2012-10-25 22:28:12 +0200 | [diff] [blame] | 1087 | current->flags &= |
| 1088 | ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE); |
Linus Torvalds | 7ab02af | 2010-02-02 12:37:44 -0800 | [diff] [blame] | 1089 | flush_thread(); |
| 1090 | current->personality &= ~bprm->per_clear; |
| 1091 | |
Linus Torvalds | 221af7f | 2010-01-28 22:14:42 -0800 | [diff] [blame] | 1092 | return 0; |
| 1093 | |
| 1094 | out: |
| 1095 | return retval; |
| 1096 | } |
| 1097 | EXPORT_SYMBOL(flush_old_exec); |
| 1098 | |
Al Viro | 1b5d783 | 2011-06-19 12:49:47 -0400 | [diff] [blame] | 1099 | void would_dump(struct linux_binprm *bprm, struct file *file) |
| 1100 | { |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 1101 | if (inode_permission(file_inode(file), MAY_READ) < 0) |
Al Viro | 1b5d783 | 2011-06-19 12:49:47 -0400 | [diff] [blame] | 1102 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
| 1103 | } |
| 1104 | EXPORT_SYMBOL(would_dump); |
| 1105 | |
Linus Torvalds | 221af7f | 2010-01-28 22:14:42 -0800 | [diff] [blame] | 1106 | void setup_new_exec(struct linux_binprm * bprm) |
| 1107 | { |
Linus Torvalds | 221af7f | 2010-01-28 22:14:42 -0800 | [diff] [blame] | 1108 | arch_pick_mmap_layout(current->mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | |
| 1110 | /* This is the point of no return */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | current->sas_ss_sp = current->sas_ss_size = 0; |
| 1112 | |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 1113 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) |
Kees Cook | e579d2c | 2013-02-27 17:03:15 -0800 | [diff] [blame^] | 1114 | set_dumpable(current->mm, SUID_DUMP_USER); |
Alan Cox | d6e7114 | 2005-06-23 00:09:43 -0700 | [diff] [blame] | 1115 | else |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1116 | set_dumpable(current->mm, suid_dumpable); |
Alan Cox | d6e7114 | 2005-06-23 00:09:43 -0700 | [diff] [blame] | 1117 | |
Heiko Carstens | 96e02d1 | 2012-02-04 10:47:10 +0100 | [diff] [blame] | 1118 | set_task_comm(current, bprm->tcomm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1119 | |
Benjamin Herrenschmidt | 0551fbd | 2006-02-28 16:59:19 -0800 | [diff] [blame] | 1120 | /* Set the new mm task size. We have to do that late because it may |
| 1121 | * depend on TIF_32BIT which is only updated in flush_thread() on |
| 1122 | * some architectures like powerpc |
| 1123 | */ |
| 1124 | current->mm->task_size = TASK_SIZE; |
| 1125 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1126 | /* install the new credentials */ |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 1127 | if (!uid_eq(bprm->cred->uid, current_euid()) || |
| 1128 | !gid_eq(bprm->cred->gid, current_egid())) { |
Marcel Holtmann | d2d56c5 | 2007-08-17 21:47:58 +0200 | [diff] [blame] | 1129 | current->pdeath_signal = 0; |
Al Viro | 1b5d783 | 2011-06-19 12:49:47 -0400 | [diff] [blame] | 1130 | } else { |
| 1131 | would_dump(bprm, bprm->file); |
| 1132 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) |
| 1133 | set_dumpable(current->mm, suid_dumpable); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | } |
| 1135 | |
Ingo Molnar | f65cb45 | 2008-12-16 13:40:44 +0100 | [diff] [blame] | 1136 | /* |
| 1137 | * Flush performance counters when crossing a |
| 1138 | * security domain: |
| 1139 | */ |
| 1140 | if (!get_dumpable(current->mm)) |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1141 | perf_event_exit_task(current); |
Ingo Molnar | f65cb45 | 2008-12-16 13:40:44 +0100 | [diff] [blame] | 1142 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1143 | /* An exec changes our domain. We are no longer part of the thread |
| 1144 | group */ |
| 1145 | |
| 1146 | current->self_exec_id++; |
| 1147 | |
| 1148 | flush_signal_handlers(current, 0); |
Al Viro | 6a6d27d | 2012-08-21 09:56:33 -0400 | [diff] [blame] | 1149 | do_close_on_exec(current->files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | } |
Linus Torvalds | 221af7f | 2010-01-28 22:14:42 -0800 | [diff] [blame] | 1151 | EXPORT_SYMBOL(setup_new_exec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1152 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1153 | /* |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1154 | * Prepare credentials and lock ->cred_guard_mutex. |
| 1155 | * install_exec_creds() commits the new creds and drops the lock. |
| 1156 | * Or, if exec fails before, free_bprm() should release ->cred and |
| 1157 | * and unlock. |
| 1158 | */ |
| 1159 | int prepare_bprm_creds(struct linux_binprm *bprm) |
| 1160 | { |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 1161 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1162 | return -ERESTARTNOINTR; |
| 1163 | |
| 1164 | bprm->cred = prepare_exec_creds(); |
| 1165 | if (likely(bprm->cred)) |
| 1166 | return 0; |
| 1167 | |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 1168 | mutex_unlock(¤t->signal->cred_guard_mutex); |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1169 | return -ENOMEM; |
| 1170 | } |
| 1171 | |
| 1172 | void free_bprm(struct linux_binprm *bprm) |
| 1173 | { |
| 1174 | free_arg_pages(bprm); |
| 1175 | if (bprm->cred) { |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 1176 | mutex_unlock(¤t->signal->cred_guard_mutex); |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1177 | abort_creds(bprm->cred); |
| 1178 | } |
Kees Cook | b66c598 | 2012-12-20 15:05:16 -0800 | [diff] [blame] | 1179 | /* If a binfmt changed the interp, free it. */ |
| 1180 | if (bprm->interp != bprm->filename) |
| 1181 | kfree(bprm->interp); |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1182 | kfree(bprm); |
| 1183 | } |
| 1184 | |
Kees Cook | b66c598 | 2012-12-20 15:05:16 -0800 | [diff] [blame] | 1185 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) |
| 1186 | { |
| 1187 | /* If a binfmt changed the interp, free it first. */ |
| 1188 | if (bprm->interp != bprm->filename) |
| 1189 | kfree(bprm->interp); |
| 1190 | bprm->interp = kstrdup(interp, GFP_KERNEL); |
| 1191 | if (!bprm->interp) |
| 1192 | return -ENOMEM; |
| 1193 | return 0; |
| 1194 | } |
| 1195 | EXPORT_SYMBOL(bprm_change_interp); |
| 1196 | |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1197 | /* |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1198 | * install the new credentials for this executable |
| 1199 | */ |
| 1200 | void install_exec_creds(struct linux_binprm *bprm) |
| 1201 | { |
| 1202 | security_bprm_committing_creds(bprm); |
| 1203 | |
| 1204 | commit_creds(bprm->cred); |
| 1205 | bprm->cred = NULL; |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1206 | /* |
| 1207 | * cred_guard_mutex must be held at least to this point to prevent |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1208 | * ptrace_attach() from altering our determination of the task's |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1209 | * credentials; any time after this it may be unlocked. |
| 1210 | */ |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1211 | security_bprm_committed_creds(bprm); |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 1212 | mutex_unlock(¤t->signal->cred_guard_mutex); |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1213 | } |
| 1214 | EXPORT_SYMBOL(install_exec_creds); |
| 1215 | |
| 1216 | /* |
| 1217 | * determine how safe it is to execute the proposed program |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 1218 | * - the caller must hold ->cred_guard_mutex to protect against |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1219 | * PTRACE_ATTACH |
| 1220 | */ |
Al Viro | f47ec3f | 2011-11-21 21:15:42 -0500 | [diff] [blame] | 1221 | static int check_unsafe_exec(struct linux_binprm *bprm) |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1222 | { |
David Howells | 0bf2f3a | 2009-02-06 11:45:46 +0000 | [diff] [blame] | 1223 | struct task_struct *p = current, *t; |
Al Viro | f1191b5 | 2009-03-30 07:35:18 -0400 | [diff] [blame] | 1224 | unsigned n_fs; |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1225 | int res = 0; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1226 | |
Tejun Heo | 4b9d33e | 2011-06-17 16:50:38 +0200 | [diff] [blame] | 1227 | if (p->ptrace) { |
| 1228 | if (p->ptrace & PT_PTRACE_CAP) |
| 1229 | bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; |
| 1230 | else |
| 1231 | bprm->unsafe |= LSM_UNSAFE_PTRACE; |
| 1232 | } |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1233 | |
Andy Lutomirski | 259e5e6 | 2012-04-12 16:47:50 -0500 | [diff] [blame] | 1234 | /* |
| 1235 | * This isn't strictly necessary, but it makes it harder for LSMs to |
| 1236 | * mess up. |
| 1237 | */ |
| 1238 | if (current->no_new_privs) |
| 1239 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
| 1240 | |
David Howells | 0bf2f3a | 2009-02-06 11:45:46 +0000 | [diff] [blame] | 1241 | n_fs = 1; |
Nick Piggin | 2a4419b | 2010-08-18 04:37:33 +1000 | [diff] [blame] | 1242 | spin_lock(&p->fs->lock); |
Oleg Nesterov | 437f7fd | 2009-04-24 01:02:45 +0200 | [diff] [blame] | 1243 | rcu_read_lock(); |
David Howells | 0bf2f3a | 2009-02-06 11:45:46 +0000 | [diff] [blame] | 1244 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
| 1245 | if (t->fs == p->fs) |
| 1246 | n_fs++; |
David Howells | 0bf2f3a | 2009-02-06 11:45:46 +0000 | [diff] [blame] | 1247 | } |
Oleg Nesterov | 437f7fd | 2009-04-24 01:02:45 +0200 | [diff] [blame] | 1248 | rcu_read_unlock(); |
David Howells | 0bf2f3a | 2009-02-06 11:45:46 +0000 | [diff] [blame] | 1249 | |
Al Viro | f1191b5 | 2009-03-30 07:35:18 -0400 | [diff] [blame] | 1250 | if (p->fs->users > n_fs) { |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1251 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1252 | } else { |
Oleg Nesterov | 8c652f9 | 2009-04-24 01:01:56 +0200 | [diff] [blame] | 1253 | res = -EAGAIN; |
| 1254 | if (!p->fs->in_exec) { |
| 1255 | p->fs->in_exec = 1; |
| 1256 | res = 1; |
| 1257 | } |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1258 | } |
Nick Piggin | 2a4419b | 2010-08-18 04:37:33 +1000 | [diff] [blame] | 1259 | spin_unlock(&p->fs->lock); |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1260 | |
| 1261 | return res; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1262 | } |
| 1263 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1264 | /* |
| 1265 | * Fill the binprm structure from the inode. |
| 1266 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1267 | * |
| 1268 | * This may be called multiple times for binary chains (scripts for example). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | */ |
| 1270 | int prepare_binprm(struct linux_binprm *bprm) |
| 1271 | { |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1272 | umode_t mode; |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 1273 | struct inode * inode = file_inode(bprm->file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1274 | int retval; |
| 1275 | |
| 1276 | mode = inode->i_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1277 | if (bprm->file->f_op == NULL) |
| 1278 | return -EACCES; |
| 1279 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1280 | /* clear any previous set[ug]id data from a previous binary */ |
| 1281 | bprm->cred->euid = current_euid(); |
| 1282 | bprm->cred->egid = current_egid(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1283 | |
Andy Lutomirski | 259e5e6 | 2012-04-12 16:47:50 -0500 | [diff] [blame] | 1284 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) && |
Eric W. Biederman | 3cdf5b4 | 2011-11-21 16:40:54 -0800 | [diff] [blame] | 1285 | !current->no_new_privs && |
| 1286 | kuid_has_mapping(bprm->cred->user_ns, inode->i_uid) && |
| 1287 | kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1288 | /* Set-uid? */ |
| 1289 | if (mode & S_ISUID) { |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1290 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
| 1291 | bprm->cred->euid = inode->i_uid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1292 | } |
| 1293 | |
| 1294 | /* Set-gid? */ |
| 1295 | /* |
| 1296 | * If setgid is set but no group execute bit then this |
| 1297 | * is a candidate for mandatory locking, not a setgid |
| 1298 | * executable. |
| 1299 | */ |
| 1300 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1301 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
| 1302 | bprm->cred->egid = inode->i_gid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | } |
| 1304 | } |
| 1305 | |
| 1306 | /* fill in binprm security blob */ |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1307 | retval = security_bprm_set_creds(bprm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1308 | if (retval) |
| 1309 | return retval; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1310 | bprm->cred_prepared = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1311 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1312 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
| 1313 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1314 | } |
| 1315 | |
| 1316 | EXPORT_SYMBOL(prepare_binprm); |
| 1317 | |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1318 | /* |
| 1319 | * Arguments are '\0' separated strings found at the location bprm->p |
| 1320 | * points to; chop off the first by relocating brpm->p to right after |
| 1321 | * the first '\0' encountered. |
| 1322 | */ |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1323 | int remove_arg_zero(struct linux_binprm *bprm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1324 | { |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1325 | int ret = 0; |
| 1326 | unsigned long offset; |
| 1327 | char *kaddr; |
| 1328 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1330 | if (!bprm->argc) |
| 1331 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1332 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1333 | do { |
| 1334 | offset = bprm->p & ~PAGE_MASK; |
| 1335 | page = get_arg_page(bprm, bprm->p, 0); |
| 1336 | if (!page) { |
| 1337 | ret = -EFAULT; |
| 1338 | goto out; |
| 1339 | } |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 1340 | kaddr = kmap_atomic(page); |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1341 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1342 | for (; offset < PAGE_SIZE && kaddr[offset]; |
| 1343 | offset++, bprm->p++) |
| 1344 | ; |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1345 | |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 1346 | kunmap_atomic(kaddr); |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1347 | put_arg_page(page); |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1348 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1349 | if (offset == PAGE_SIZE) |
| 1350 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); |
| 1351 | } while (offset == PAGE_SIZE); |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1352 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1353 | bprm->p++; |
| 1354 | bprm->argc--; |
| 1355 | ret = 0; |
Nick Piggin | 4fc75ff | 2007-05-08 00:25:16 -0700 | [diff] [blame] | 1356 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1357 | out: |
| 1358 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1359 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1360 | EXPORT_SYMBOL(remove_arg_zero); |
| 1361 | |
| 1362 | /* |
| 1363 | * cycle the list of binary formats handler, until one recognizes the image |
| 1364 | */ |
Al Viro | 3c456bf | 2012-10-20 21:53:31 -0400 | [diff] [blame] | 1365 | int search_binary_handler(struct linux_binprm *bprm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1366 | { |
Roland McGrath | 85f3346 | 2008-12-09 19:36:38 -0800 | [diff] [blame] | 1367 | unsigned int depth = bprm->recursion_depth; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1368 | int try,retval; |
| 1369 | struct linux_binfmt *fmt; |
Oleg Nesterov | 6308191 | 2012-03-30 18:26:36 +0200 | [diff] [blame] | 1370 | pid_t old_pid, old_vpid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | |
Kees Cook | d740269 | 2012-12-17 16:03:20 -0800 | [diff] [blame] | 1372 | /* This allows 4 levels of binfmt rewrites before failing hard. */ |
| 1373 | if (depth > 5) |
| 1374 | return -ELOOP; |
| 1375 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1376 | retval = security_bprm_check(bprm); |
| 1377 | if (retval) |
| 1378 | return retval; |
| 1379 | |
Al Viro | 473ae30 | 2006-04-26 14:04:08 -0400 | [diff] [blame] | 1380 | retval = audit_bprm(bprm); |
| 1381 | if (retval) |
| 1382 | return retval; |
| 1383 | |
Denys Vlasenko | bb188d7 | 2011-06-29 04:13:39 +0200 | [diff] [blame] | 1384 | /* Need to fetch pid before load_binary changes it */ |
Oleg Nesterov | 6308191 | 2012-03-30 18:26:36 +0200 | [diff] [blame] | 1385 | old_pid = current->pid; |
Denys Vlasenko | bb188d7 | 2011-06-29 04:13:39 +0200 | [diff] [blame] | 1386 | rcu_read_lock(); |
Oleg Nesterov | 6308191 | 2012-03-30 18:26:36 +0200 | [diff] [blame] | 1387 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); |
Denys Vlasenko | bb188d7 | 2011-06-29 04:13:39 +0200 | [diff] [blame] | 1388 | rcu_read_unlock(); |
| 1389 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1390 | retval = -ENOENT; |
| 1391 | for (try=0; try<2; try++) { |
| 1392 | read_lock(&binfmt_lock); |
Alexey Dobriyan | e4dc1b1 | 2007-10-16 23:26:03 -0700 | [diff] [blame] | 1393 | list_for_each_entry(fmt, &formats, lh) { |
Al Viro | 71613c3 | 2012-10-20 22:00:48 -0400 | [diff] [blame] | 1394 | int (*fn)(struct linux_binprm *) = fmt->load_binary; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1395 | if (!fn) |
| 1396 | continue; |
| 1397 | if (!try_module_get(fmt->module)) |
| 1398 | continue; |
| 1399 | read_unlock(&binfmt_lock); |
Kees Cook | d740269 | 2012-12-17 16:03:20 -0800 | [diff] [blame] | 1400 | bprm->recursion_depth = depth + 1; |
Al Viro | 71613c3 | 2012-10-20 22:00:48 -0400 | [diff] [blame] | 1401 | retval = fn(bprm); |
Roland McGrath | 85f3346 | 2008-12-09 19:36:38 -0800 | [diff] [blame] | 1402 | bprm->recursion_depth = depth; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1403 | if (retval >= 0) { |
David Smith | 4ff16c2 | 2012-02-07 10:11:05 -0600 | [diff] [blame] | 1404 | if (depth == 0) { |
| 1405 | trace_sched_process_exec(current, old_pid, bprm); |
Oleg Nesterov | 6308191 | 2012-03-30 18:26:36 +0200 | [diff] [blame] | 1406 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); |
David Smith | 4ff16c2 | 2012-02-07 10:11:05 -0600 | [diff] [blame] | 1407 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | put_binfmt(fmt); |
| 1409 | allow_write_access(bprm->file); |
| 1410 | if (bprm->file) |
| 1411 | fput(bprm->file); |
| 1412 | bprm->file = NULL; |
| 1413 | current->did_exec = 1; |
Matt Helsley | 9f46080 | 2005-11-07 00:59:16 -0800 | [diff] [blame] | 1414 | proc_exec_connector(current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | return retval; |
| 1416 | } |
| 1417 | read_lock(&binfmt_lock); |
| 1418 | put_binfmt(fmt); |
| 1419 | if (retval != -ENOEXEC || bprm->mm == NULL) |
| 1420 | break; |
| 1421 | if (!bprm->file) { |
| 1422 | read_unlock(&binfmt_lock); |
| 1423 | return retval; |
| 1424 | } |
| 1425 | } |
| 1426 | read_unlock(&binfmt_lock); |
Tetsuo Handa | b4edf8b | 2011-07-26 16:08:42 -0700 | [diff] [blame] | 1427 | #ifdef CONFIG_MODULES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1428 | if (retval != -ENOEXEC || bprm->mm == NULL) { |
| 1429 | break; |
Johannes Berg | 5f4123b | 2008-07-09 10:28:40 +0200 | [diff] [blame] | 1430 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1431 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
| 1432 | if (printable(bprm->buf[0]) && |
| 1433 | printable(bprm->buf[1]) && |
| 1434 | printable(bprm->buf[2]) && |
| 1435 | printable(bprm->buf[3])) |
| 1436 | break; /* -ENOEXEC */ |
Tetsuo Handa | 9121935 | 2011-07-26 16:08:41 -0700 | [diff] [blame] | 1437 | if (try) |
| 1438 | break; /* -ENOEXEC */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1439 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1440 | } |
Tetsuo Handa | b4edf8b | 2011-07-26 16:08:42 -0700 | [diff] [blame] | 1441 | #else |
| 1442 | break; |
| 1443 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1444 | } |
| 1445 | return retval; |
| 1446 | } |
| 1447 | |
| 1448 | EXPORT_SYMBOL(search_binary_handler); |
| 1449 | |
| 1450 | /* |
| 1451 | * sys_execve() executes a new program. |
| 1452 | */ |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 1453 | static int do_execve_common(const char *filename, |
| 1454 | struct user_arg_ptr argv, |
Al Viro | 835ab32 | 2012-10-20 21:50:59 -0400 | [diff] [blame] | 1455 | struct user_arg_ptr envp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1456 | { |
| 1457 | struct linux_binprm *bprm; |
| 1458 | struct file *file; |
Al Viro | 3b12538 | 2008-04-22 05:31:30 -0400 | [diff] [blame] | 1459 | struct files_struct *displaced; |
Oleg Nesterov | 8c652f9 | 2009-04-24 01:01:56 +0200 | [diff] [blame] | 1460 | bool clear_in_exec; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1461 | int retval; |
Vasiliy Kulikov | 72fa599 | 2011-08-08 19:02:04 +0400 | [diff] [blame] | 1462 | const struct cred *cred = current_cred(); |
| 1463 | |
| 1464 | /* |
| 1465 | * We move the actual failure in case of RLIMIT_NPROC excess from |
| 1466 | * set*uid() to execve() because too many poorly written programs |
| 1467 | * don't check setuid() return code. Here we additionally recheck |
| 1468 | * whether NPROC limit is still exceeded. |
| 1469 | */ |
| 1470 | if ((current->flags & PF_NPROC_EXCEEDED) && |
| 1471 | atomic_read(&cred->user->processes) > rlimit(RLIMIT_NPROC)) { |
| 1472 | retval = -EAGAIN; |
| 1473 | goto out_ret; |
| 1474 | } |
| 1475 | |
| 1476 | /* We're below the limit (still or again), so we don't want to make |
| 1477 | * further execve() calls fail. */ |
| 1478 | current->flags &= ~PF_NPROC_EXCEEDED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1479 | |
Al Viro | 3b12538 | 2008-04-22 05:31:30 -0400 | [diff] [blame] | 1480 | retval = unshare_files(&displaced); |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 1481 | if (retval) |
| 1482 | goto out_ret; |
| 1483 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1484 | retval = -ENOMEM; |
Oliver Neukum | 11b0b5a | 2006-03-25 03:08:13 -0800 | [diff] [blame] | 1485 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1486 | if (!bprm) |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 1487 | goto out_files; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1488 | |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1489 | retval = prepare_bprm_creds(bprm); |
| 1490 | if (retval) |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1491 | goto out_free; |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1492 | |
| 1493 | retval = check_unsafe_exec(bprm); |
Oleg Nesterov | 8c652f9 | 2009-04-24 01:01:56 +0200 | [diff] [blame] | 1494 | if (retval < 0) |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1495 | goto out_free; |
Oleg Nesterov | 8c652f9 | 2009-04-24 01:01:56 +0200 | [diff] [blame] | 1496 | clear_in_exec = retval; |
Oleg Nesterov | a2a8474 | 2009-09-05 11:17:13 -0700 | [diff] [blame] | 1497 | current->in_execve = 1; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1498 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1499 | file = open_exec(filename); |
| 1500 | retval = PTR_ERR(file); |
| 1501 | if (IS_ERR(file)) |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1502 | goto out_unmark; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1503 | |
| 1504 | sched_exec(); |
| 1505 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1506 | bprm->file = file; |
| 1507 | bprm->filename = filename; |
| 1508 | bprm->interp = filename; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1509 | |
| 1510 | retval = bprm_mm_init(bprm); |
| 1511 | if (retval) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1512 | goto out_file; |
| 1513 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1514 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1515 | if ((retval = bprm->argc) < 0) |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1516 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1517 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1518 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1519 | if ((retval = bprm->envc) < 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1520 | goto out; |
| 1521 | |
| 1522 | retval = prepare_binprm(bprm); |
| 1523 | if (retval < 0) |
| 1524 | goto out; |
| 1525 | |
| 1526 | retval = copy_strings_kernel(1, &bprm->filename, bprm); |
| 1527 | if (retval < 0) |
| 1528 | goto out; |
| 1529 | |
| 1530 | bprm->exec = bprm->p; |
| 1531 | retval = copy_strings(bprm->envc, envp, bprm); |
| 1532 | if (retval < 0) |
| 1533 | goto out; |
| 1534 | |
| 1535 | retval = copy_strings(bprm->argc, argv, bprm); |
| 1536 | if (retval < 0) |
| 1537 | goto out; |
| 1538 | |
Al Viro | 3c456bf | 2012-10-20 21:53:31 -0400 | [diff] [blame] | 1539 | retval = search_binary_handler(bprm); |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1540 | if (retval < 0) |
| 1541 | goto out; |
| 1542 | |
| 1543 | /* execve succeeded */ |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1544 | current->fs->in_exec = 0; |
Kentaro Takeda | f9ce1f1 | 2009-02-05 17:18:11 +0900 | [diff] [blame] | 1545 | current->in_execve = 0; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1546 | acct_update_integrals(current); |
| 1547 | free_bprm(bprm); |
| 1548 | if (displaced) |
| 1549 | put_files_struct(displaced); |
| 1550 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1551 | |
| 1552 | out: |
Oleg Nesterov | 3c77f84 | 2010-11-30 20:55:34 +0100 | [diff] [blame] | 1553 | if (bprm->mm) { |
| 1554 | acct_arg_size(bprm, 0); |
| 1555 | mmput(bprm->mm); |
| 1556 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1557 | |
| 1558 | out_file: |
| 1559 | if (bprm->file) { |
| 1560 | allow_write_access(bprm->file); |
| 1561 | fput(bprm->file); |
| 1562 | } |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1563 | |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1564 | out_unmark: |
Oleg Nesterov | 8c652f9 | 2009-04-24 01:01:56 +0200 | [diff] [blame] | 1565 | if (clear_in_exec) |
| 1566 | current->fs->in_exec = 0; |
Kentaro Takeda | f9ce1f1 | 2009-02-05 17:18:11 +0900 | [diff] [blame] | 1567 | current->in_execve = 0; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 1568 | |
| 1569 | out_free: |
Al Viro | 08a6fac | 2008-05-10 16:38:25 -0400 | [diff] [blame] | 1570 | free_bprm(bprm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1571 | |
Al Viro | fd8328b | 2008-04-22 05:11:59 -0400 | [diff] [blame] | 1572 | out_files: |
Al Viro | 3b12538 | 2008-04-22 05:31:30 -0400 | [diff] [blame] | 1573 | if (displaced) |
| 1574 | reset_files_struct(displaced); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1575 | out_ret: |
| 1576 | return retval; |
| 1577 | } |
| 1578 | |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 1579 | int do_execve(const char *filename, |
| 1580 | const char __user *const __user *__argv, |
Al Viro | da3d4c5 | 2012-10-20 21:49:33 -0400 | [diff] [blame] | 1581 | const char __user *const __user *__envp) |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 1582 | { |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 1583 | struct user_arg_ptr argv = { .ptr.native = __argv }; |
| 1584 | struct user_arg_ptr envp = { .ptr.native = __envp }; |
Al Viro | 835ab32 | 2012-10-20 21:50:59 -0400 | [diff] [blame] | 1585 | return do_execve_common(filename, argv, envp); |
Oleg Nesterov | ba2d0162 | 2011-03-06 18:02:37 +0100 | [diff] [blame] | 1586 | } |
| 1587 | |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 1588 | #ifdef CONFIG_COMPAT |
Al Viro | d03d26e | 2012-10-20 21:46:25 -0400 | [diff] [blame] | 1589 | static int compat_do_execve(const char *filename, |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1590 | const compat_uptr_t __user *__argv, |
Al Viro | d03d26e | 2012-10-20 21:46:25 -0400 | [diff] [blame] | 1591 | const compat_uptr_t __user *__envp) |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 1592 | { |
| 1593 | struct user_arg_ptr argv = { |
| 1594 | .is_compat = true, |
| 1595 | .ptr.compat = __argv, |
| 1596 | }; |
| 1597 | struct user_arg_ptr envp = { |
| 1598 | .is_compat = true, |
| 1599 | .ptr.compat = __envp, |
| 1600 | }; |
Al Viro | 835ab32 | 2012-10-20 21:50:59 -0400 | [diff] [blame] | 1601 | return do_execve_common(filename, argv, envp); |
Oleg Nesterov | 0e02846 | 2011-03-06 18:02:54 +0100 | [diff] [blame] | 1602 | } |
| 1603 | #endif |
| 1604 | |
Oleg Nesterov | 964ee7d | 2009-09-23 15:56:59 -0700 | [diff] [blame] | 1605 | void set_binfmt(struct linux_binfmt *new) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1606 | { |
Hiroshi Shimamoto | 801460d | 2009-09-23 15:57:41 -0700 | [diff] [blame] | 1607 | struct mm_struct *mm = current->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | |
Hiroshi Shimamoto | 801460d | 2009-09-23 15:57:41 -0700 | [diff] [blame] | 1609 | if (mm->binfmt) |
| 1610 | module_put(mm->binfmt->module); |
| 1611 | |
| 1612 | mm->binfmt = new; |
Oleg Nesterov | 964ee7d | 2009-09-23 15:56:59 -0700 | [diff] [blame] | 1613 | if (new) |
| 1614 | __module_get(new->module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1615 | } |
| 1616 | |
| 1617 | EXPORT_SYMBOL(set_binfmt); |
| 1618 | |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1619 | /* |
| 1620 | * set_dumpable converts traditional three-value dumpable to two flags and |
| 1621 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but |
| 1622 | * these bits are not changed atomically. So get_dumpable can observe the |
| 1623 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable |
| 1624 | * return either old dumpable or new one by paying attention to the order of |
| 1625 | * modifying the bits. |
| 1626 | * |
| 1627 | * dumpable | mm->flags (binary) |
| 1628 | * old new | initial interim final |
| 1629 | * ---------+----------------------- |
| 1630 | * 0 1 | 00 01 01 |
| 1631 | * 0 2 | 00 10(*) 11 |
| 1632 | * 1 0 | 01 00 00 |
| 1633 | * 1 2 | 01 11 11 |
| 1634 | * 2 0 | 11 10(*) 00 |
| 1635 | * 2 1 | 11 11 01 |
| 1636 | * |
| 1637 | * (*) get_dumpable regards interim value of 10 as 11. |
| 1638 | */ |
| 1639 | void set_dumpable(struct mm_struct *mm, int value) |
| 1640 | { |
| 1641 | switch (value) { |
Kees Cook | e579d2c | 2013-02-27 17:03:15 -0800 | [diff] [blame^] | 1642 | case SUID_DUMP_DISABLE: |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1643 | clear_bit(MMF_DUMPABLE, &mm->flags); |
| 1644 | smp_wmb(); |
| 1645 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
| 1646 | break; |
Kees Cook | e579d2c | 2013-02-27 17:03:15 -0800 | [diff] [blame^] | 1647 | case SUID_DUMP_USER: |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1648 | set_bit(MMF_DUMPABLE, &mm->flags); |
| 1649 | smp_wmb(); |
| 1650 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
| 1651 | break; |
Kees Cook | e579d2c | 2013-02-27 17:03:15 -0800 | [diff] [blame^] | 1652 | case SUID_DUMP_ROOT: |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1653 | set_bit(MMF_DUMP_SECURELY, &mm->flags); |
| 1654 | smp_wmb(); |
| 1655 | set_bit(MMF_DUMPABLE, &mm->flags); |
| 1656 | break; |
| 1657 | } |
| 1658 | } |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1659 | |
Alex Kelly | 10c28d9 | 2012-09-26 21:52:08 -0400 | [diff] [blame] | 1660 | int __get_dumpable(unsigned long mm_flags) |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1661 | { |
| 1662 | int ret; |
| 1663 | |
Masami Hiramatsu | 30736a4 | 2010-03-05 13:44:12 -0800 | [diff] [blame] | 1664 | ret = mm_flags & MMF_DUMPABLE_MASK; |
Kees Cook | e579d2c | 2013-02-27 17:03:15 -0800 | [diff] [blame^] | 1665 | return (ret > SUID_DUMP_USER) ? SUID_DUMP_ROOT : ret; |
Kawai, Hidehiro | 6c5d523 | 2007-07-19 01:48:27 -0700 | [diff] [blame] | 1666 | } |
| 1667 | |
Masami Hiramatsu | 30736a4 | 2010-03-05 13:44:12 -0800 | [diff] [blame] | 1668 | int get_dumpable(struct mm_struct *mm) |
| 1669 | { |
| 1670 | return __get_dumpable(mm->flags); |
| 1671 | } |
| 1672 | |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1673 | SYSCALL_DEFINE3(execve, |
| 1674 | const char __user *, filename, |
| 1675 | const char __user *const __user *, argv, |
| 1676 | const char __user *const __user *, envp) |
| 1677 | { |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 1678 | struct filename *path = getname(filename); |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1679 | int error = PTR_ERR(path); |
| 1680 | if (!IS_ERR(path)) { |
Al Viro | da3d4c5 | 2012-10-20 21:49:33 -0400 | [diff] [blame] | 1681 | error = do_execve(path->name, argv, envp); |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1682 | putname(path); |
| 1683 | } |
| 1684 | return error; |
| 1685 | } |
| 1686 | #ifdef CONFIG_COMPAT |
| 1687 | asmlinkage long compat_sys_execve(const char __user * filename, |
| 1688 | const compat_uptr_t __user * argv, |
| 1689 | const compat_uptr_t __user * envp) |
| 1690 | { |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 1691 | struct filename *path = getname(filename); |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1692 | int error = PTR_ERR(path); |
| 1693 | if (!IS_ERR(path)) { |
Al Viro | d03d26e | 2012-10-20 21:46:25 -0400 | [diff] [blame] | 1694 | error = compat_do_execve(path->name, argv, envp); |
Al Viro | 38b983b | 2012-09-30 13:38:55 -0400 | [diff] [blame] | 1695 | putname(path); |
| 1696 | } |
| 1697 | return error; |
| 1698 | } |
| 1699 | #endif |