| /* |
| * linux/fs/binfmt_aout.c |
| * |
| * Copyright (C) 1991, 1992, 1996 Linus Torvalds |
| */ |
| |
| #include <linux/module.h> |
| |
| #include <linux/time.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/a.out.h> |
| #include <linux/errno.h> |
| #include <linux/signal.h> |
| #include <linux/string.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/stat.h> |
| #include <linux/fcntl.h> |
| #include <linux/ptrace.h> |
| #include <linux/user.h> |
| #include <linux/binfmts.h> |
| #include <linux/personality.h> |
| #include <linux/init.h> |
| #include <linux/coredump.h> |
| #include <linux/slab.h> |
| |
| #include <asm/system.h> |
| #include <asm/uaccess.h> |
| #include <asm/cacheflush.h> |
| #include <asm/a.out-core.h> |
| |
| static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); |
| static int load_aout_library(struct file*); |
| static int aout_core_dump(struct coredump_params *cprm); |
| |
| static struct linux_binfmt aout_format = { |
| .module = THIS_MODULE, |
| .load_binary = load_aout_binary, |
| .load_shlib = load_aout_library, |
| .core_dump = aout_core_dump, |
| .min_coredump = PAGE_SIZE |
| }; |
| |
| #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE) |
| |
| static int set_brk(unsigned long start, unsigned long end) |
| { |
| start = PAGE_ALIGN(start); |
| end = PAGE_ALIGN(end); |
| if (end > start) { |
| unsigned long addr; |
| down_write(¤t->mm->mmap_sem); |
| addr = do_brk(start, end - start); |
| up_write(¤t->mm->mmap_sem); |
| if (BAD_ADDR(addr)) |
| return addr; |
| } |
| return 0; |
| } |
| |
| /* |
| * Routine writes a core dump image in the current directory. |
| * Currently only a stub-function. |
| * |
| * Note that setuid/setgid files won't make a core-dump if the uid/gid |
| * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" |
| * field, which also makes sure the core-dumps won't be recursive if the |
| * dumping of the process results in another error.. |
| */ |
| |
| static int aout_core_dump(struct coredump_params *cprm) |
| { |
| struct file *file = cprm->file; |
| mm_segment_t fs; |
| int has_dumped = 0; |
| void __user *dump_start; |
| int dump_size; |
| struct user dump; |
| #ifdef __alpha__ |
| # define START_DATA(u) ((void __user *)u.start_data) |
| #else |
| # define START_DATA(u) ((void __user *)((u.u_tsize << PAGE_SHIFT) + \ |
| u.start_code)) |
| #endif |
| # define START_STACK(u) ((void __user *)u.start_stack) |
| |
| fs = get_fs(); |
| set_fs(KERNEL_DS); |
| has_dumped = 1; |
| current->flags |= PF_DUMPCORE; |
| strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); |
| dump.u_ar0 = offsetof(struct user, regs); |
| dump.signal = cprm->signr; |
| aout_dump_thread(cprm->regs, &dump); |
| |
| /* If the size of the dump file exceeds the rlimit, then see what would happen |
| if we wrote the stack, but not the data area. */ |
| if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) |
| dump.u_dsize = 0; |
| |
| /* Make sure we have enough room to write the stack and data areas. */ |
| if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) |
| dump.u_ssize = 0; |
| |
| /* make sure we actually have a data and stack area to dump */ |
| set_fs(USER_DS); |
| if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) |
| dump.u_dsize = 0; |
| if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) |
| dump.u_ssize = 0; |
| |
| set_fs(KERNEL_DS); |
| /* struct user */ |
| if (!dump_write(file, &dump, sizeof(dump))) |
| goto end_coredump; |
| /* Now dump all of the user data. Include malloced stuff as well */ |
| if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) |
| goto end_coredump; |
| /* now we start writing out the user space info */ |
| set_fs(USER_DS); |
| /* Dump the data area */ |
| if (dump.u_dsize != 0) { |
| dump_start = START_DATA(dump); |
| dump_size = dump.u_dsize << PAGE_SHIFT; |
| if (!dump_write(file, dump_start, dump_size)) |
| goto end_coredump; |
| } |
| /* Now prepare to dump the stack area */ |
| if (dump.u_ssize != 0) { |
| dump_start = START_STACK(dump); |
| dump_size = dump.u_ssize << PAGE_SHIFT; |
| if (!dump_write(file, dump_start, dump_size)) |
| goto end_coredump; |
| } |
| /* Finally dump the task struct. Not be used by gdb, but could be useful */ |
| set_fs(KERNEL_DS); |
| if (!dump_write(file, current, sizeof(*current))) |
| goto end_coredump; |
| end_coredump: |
| set_fs(fs); |
| return has_dumped; |
| } |
| |
| /* |
| * create_aout_tables() parses the env- and arg-strings in new user |
| * memory and creates the pointer tables from them, and puts their |
| * addresses on the "stack", returning the new stack pointer value. |
| */ |
| static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) |
| { |
| char __user * __user *argv; |
| char __user * __user *envp; |
| unsigned long __user *sp; |
| int argc = bprm->argc; |
| int envc = bprm->envc; |
| |
| sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); |
| #ifdef __alpha__ |
| /* whee.. test-programs are so much fun. */ |
| put_user(0, --sp); |
| put_user(0, --sp); |
| if (bprm->loader) { |
| put_user(0, --sp); |
| put_user(1003, --sp); |
| put_user(bprm->loader, --sp); |
| put_user(1002, --sp); |
| } |
| put_user(bprm->exec, --sp); |
| put_user(1001, --sp); |
| #endif |
| sp -= envc+1; |
| envp = (char __user * __user *) sp; |
| sp -= argc+1; |
| argv = (char __user * __user *) sp; |
| #ifndef __alpha__ |
| put_user((unsigned long) envp,--sp); |
| put_user((unsigned long) argv,--sp); |
| #endif |
| put_user(argc,--sp); |
| current->mm->arg_start = (unsigned long) p; |
| while (argc-->0) { |
| char c; |
| put_user(p,argv++); |
| do { |
| get_user(c,p++); |
| } while (c); |
| } |
| put_user(NULL,argv); |
| current->mm->arg_end = current->mm->env_start = (unsigned long) p; |
| while (envc-->0) { |
| char c; |
| put_user(p,envp++); |
| do { |
| get_user(c,p++); |
| } while (c); |
| } |
| put_user(NULL,envp); |
| current->mm->env_end = (unsigned long) p; |
| return sp; |
| } |
| |
| /* |
| * These are the functions used to load a.out style executables and shared |
| * libraries. There is no binary dependent code anywhere else. |
| */ |
| |
| static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs) |
| { |
| struct exec ex; |
| unsigned long error; |
| unsigned long fd_offset; |
| unsigned long rlim; |
| int retval; |
| |
| ex = *((struct exec *) bprm->buf); /* exec-header */ |
| if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && |
| N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || |
| N_TRSIZE(ex) || N_DRSIZE(ex) || |
| i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
| return -ENOEXEC; |
| } |
| |
| /* |
| * Requires a mmap handler. This prevents people from using a.out |
| * as part of an exploit attack against /proc-related vulnerabilities. |
| */ |
| if (!bprm->file->f_op || !bprm->file->f_op->mmap) |
| return -ENOEXEC; |
| |
| fd_offset = N_TXTOFF(ex); |
| |
| /* Check initial limits. This avoids letting people circumvent |
| * size limits imposed on them by creating programs with large |
| * arrays in the data or bss. |
| */ |
| rlim = rlimit(RLIMIT_DATA); |
| if (rlim >= RLIM_INFINITY) |
| rlim = ~0; |
| if (ex.a_data + ex.a_bss > rlim) |
| return -ENOMEM; |
| |
| /* Flush all traces of the currently running executable */ |
| retval = flush_old_exec(bprm); |
| if (retval) |
| return retval; |
| |
| /* OK, This is the point of no return */ |
| #ifdef __alpha__ |
| SET_AOUT_PERSONALITY(bprm, ex); |
| #else |
| set_personality(PER_LINUX); |
| #endif |
| setup_new_exec(bprm); |
| |
| current->mm->end_code = ex.a_text + |
| (current->mm->start_code = N_TXTADDR(ex)); |
| current->mm->end_data = ex.a_data + |
| (current->mm->start_data = N_DATADDR(ex)); |
| current->mm->brk = ex.a_bss + |
| (current->mm->start_brk = N_BSSADDR(ex)); |
| current->mm->free_area_cache = current->mm->mmap_base; |
| current->mm->cached_hole_size = 0; |
| |
| install_exec_creds(bprm); |
| current->flags &= ~PF_FORKNOEXEC; |
| |
| if (N_MAGIC(ex) == OMAGIC) { |
| unsigned long text_addr, map_size; |
| loff_t pos; |
| |
| text_addr = N_TXTADDR(ex); |
| |
| #ifdef __alpha__ |
| pos = fd_offset; |
| map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; |
| #else |
| pos = 32; |
| map_size = ex.a_text+ex.a_data; |
| #endif |
| down_write(¤t->mm->mmap_sem); |
| error = do_brk(text_addr & PAGE_MASK, map_size); |
| up_write(¤t->mm->mmap_sem); |
| if (error != (text_addr & PAGE_MASK)) { |
| send_sig(SIGKILL, current, 0); |
| return error; |
| } |
| |
| error = bprm->file->f_op->read(bprm->file, |
| (char __user *)text_addr, |
| ex.a_text+ex.a_data, &pos); |
| if ((signed long)error < 0) { |
| send_sig(SIGKILL, current, 0); |
| return error; |
| } |
| |
| flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data); |
| } else { |
| if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
| (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) |
| { |
| printk(KERN_NOTICE "executable not page aligned\n"); |
| } |
| |
| if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) |
| { |
| printk(KERN_WARNING |
| "fd_offset is not page aligned. Please convert program: %s\n", |
| bprm->file->f_path.dentry->d_name.name); |
| } |
| |
| if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { |
| loff_t pos = fd_offset; |
| down_write(¤t->mm->mmap_sem); |
| do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); |
| up_write(¤t->mm->mmap_sem); |
| bprm->file->f_op->read(bprm->file, |
| (char __user *)N_TXTADDR(ex), |
| ex.a_text+ex.a_data, &pos); |
| flush_icache_range((unsigned long) N_TXTADDR(ex), |
| (unsigned long) N_TXTADDR(ex) + |
| ex.a_text+ex.a_data); |
| goto beyond_if; |
| } |
| |
| down_write(¤t->mm->mmap_sem); |
| error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, |
| PROT_READ | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
| fd_offset); |
| up_write(¤t->mm->mmap_sem); |
| |
| if (error != N_TXTADDR(ex)) { |
| send_sig(SIGKILL, current, 0); |
| return error; |
| } |
| |
| down_write(¤t->mm->mmap_sem); |
| error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, |
| fd_offset + ex.a_text); |
| up_write(¤t->mm->mmap_sem); |
| if (error != N_DATADDR(ex)) { |
| send_sig(SIGKILL, current, 0); |
| return error; |
| } |
| } |
| beyond_if: |
| set_binfmt(&aout_format); |
| |
| retval = set_brk(current->mm->start_brk, current->mm->brk); |
| if (retval < 0) { |
| send_sig(SIGKILL, current, 0); |
| return retval; |
| } |
| |
| retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); |
| if (retval < 0) { |
| /* Someone check-me: is this error path enough? */ |
| send_sig(SIGKILL, current, 0); |
| return retval; |
| } |
| |
| current->mm->start_stack = |
| (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); |
| #ifdef __alpha__ |
| regs->gp = ex.a_gpvalue; |
| #endif |
| start_thread(regs, ex.a_entry, current->mm->start_stack); |
| return 0; |
| } |
| |
| static int load_aout_library(struct file *file) |
| { |
| struct inode * inode; |
| unsigned long bss, start_addr, len; |
| unsigned long error; |
| int retval; |
| struct exec ex; |
| |
| inode = file->f_path.dentry->d_inode; |
| |
| retval = -ENOEXEC; |
| error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); |
| if (error != sizeof(ex)) |
| goto out; |
| |
| /* We come in here for the regular a.out style of shared libraries */ |
| if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || |
| N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || |
| i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
| goto out; |
| } |
| |
| /* |
| * Requires a mmap handler. This prevents people from using a.out |
| * as part of an exploit attack against /proc-related vulnerabilities. |
| */ |
| if (!file->f_op || !file->f_op->mmap) |
| goto out; |
| |
| if (N_FLAGS(ex)) |
| goto out; |
| |
| /* For QMAGIC, the starting address is 0x20 into the page. We mask |
| this off to get the starting address for the page */ |
| |
| start_addr = ex.a_entry & 0xfffff000; |
| |
| if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { |
| loff_t pos = N_TXTOFF(ex); |
| |
| if (printk_ratelimit()) |
| { |
| printk(KERN_WARNING |
| "N_TXTOFF is not page aligned. Please convert library: %s\n", |
| file->f_path.dentry->d_name.name); |
| } |
| down_write(¤t->mm->mmap_sem); |
| do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); |
| up_write(¤t->mm->mmap_sem); |
| |
| file->f_op->read(file, (char __user *)start_addr, |
| ex.a_text + ex.a_data, &pos); |
| flush_icache_range((unsigned long) start_addr, |
| (unsigned long) start_addr + ex.a_text + ex.a_data); |
| |
| retval = 0; |
| goto out; |
| } |
| /* Now use mmap to map the library into memory. */ |
| down_write(¤t->mm->mmap_sem); |
| error = do_mmap(file, start_addr, ex.a_text + ex.a_data, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, |
| N_TXTOFF(ex)); |
| up_write(¤t->mm->mmap_sem); |
| retval = error; |
| if (error != start_addr) |
| goto out; |
| |
| len = PAGE_ALIGN(ex.a_text + ex.a_data); |
| bss = ex.a_text + ex.a_data + ex.a_bss; |
| if (bss > len) { |
| down_write(¤t->mm->mmap_sem); |
| error = do_brk(start_addr + len, bss - len); |
| up_write(¤t->mm->mmap_sem); |
| retval = error; |
| if (error != start_addr + len) |
| goto out; |
| } |
| retval = 0; |
| out: |
| return retval; |
| } |
| |
| static int __init init_aout_binfmt(void) |
| { |
| return register_binfmt(&aout_format); |
| } |
| |
| static void __exit exit_aout_binfmt(void) |
| { |
| unregister_binfmt(&aout_format); |
| } |
| |
| core_initcall(init_aout_binfmt); |
| module_exit(exit_aout_binfmt); |
| MODULE_LICENSE("GPL"); |