blob: 79713545cd631158fc4acd69dbfdcdd3c098e384 [file] [log] [blame]
Andrew Morgane338d262008-02-04 22:29:42 -08001/* Common capabilities, needed by capability.o and root_plug.o
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 */
9
Randy.Dunlapc59ede72006-01-11 12:17:46 -080010#include <linux/capability.h>
Eric Paris3fc689e2008-11-11 21:48:18 +110011#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/security.h>
16#include <linux/file.h>
17#include <linux/mm.h>
18#include <linux/mman.h>
19#include <linux/pagemap.h>
20#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/skbuff.h>
22#include <linux/netlink.h>
23#include <linux/ptrace.h>
24#include <linux/xattr.h>
25#include <linux/hugetlb.h>
Serge E. Hallynb5376772007-10-16 23:31:36 -070026#include <linux/mount.h>
Serge E. Hallynb460cbc2007-10-18 23:39:52 -070027#include <linux/sched.h>
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -070028#include <linux/prctl.h>
29#include <linux/securebits.h>
Andrew Morgan72c2d582007-10-18 03:05:59 -070030
Linus Torvalds1da177e2005-04-16 15:20:36 -070031int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
32{
David Howellsb6dff3e2008-11-14 10:39:16 +110033 NETLINK_CB(skb).eff_cap = current_cap();
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 return 0;
35}
36
Darrel Goeddelc7bdb542006-06-27 13:26:11 -070037int cap_netlink_recv(struct sk_buff *skb, int cap)
Linus Torvalds1da177e2005-04-16 15:20:36 -070038{
Darrel Goeddelc7bdb542006-06-27 13:26:11 -070039 if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 return -EPERM;
41 return 0;
42}
Linus Torvalds1da177e2005-04-16 15:20:36 -070043EXPORT_SYMBOL(cap_netlink_recv);
44
David Howells1d045982008-11-14 10:39:24 +110045/**
46 * cap_capable - Determine whether a task has a particular effective capability
47 * @tsk: The task to query
48 * @cap: The capability to check for
49 * @audit: Whether to write an audit message or not
50 *
51 * Determine whether the nominated task has the specified capability amongst
52 * its effective set, returning 0 if it does, -ve if it does not.
53 *
Andrew G. Morgana6dbb1e2008-01-21 17:18:30 -080054 * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
David Howells1d045982008-11-14 10:39:24 +110055 * function. That is, it has the reverse semantics: cap_capable() returns 0
56 * when a task has a capability, but the kernel's capable() returns 1 for this
57 * case.
Andrew G. Morgana6dbb1e2008-01-21 17:18:30 -080058 */
Eric Paris06112162008-11-11 22:02:50 +110059int cap_capable(struct task_struct *tsk, int cap, int audit)
Linus Torvalds1da177e2005-04-16 15:20:36 -070060{
David Howellsc69e8d92008-11-14 10:39:19 +110061 __u32 cap_raised;
62
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 /* Derived from include/linux/sched.h:capable. */
David Howellsc69e8d92008-11-14 10:39:19 +110064 rcu_read_lock();
65 cap_raised = cap_raised(__task_cred(tsk)->cap_effective, cap);
66 rcu_read_unlock();
67 return cap_raised ? 0 : -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068}
69
David Howells1d045982008-11-14 10:39:24 +110070/**
71 * cap_settime - Determine whether the current process may set the system clock
72 * @ts: The time to set
73 * @tz: The timezone to set
74 *
75 * Determine whether the current process may set the system clock and timezone
76 * information, returning 0 if permission granted, -ve if denied.
77 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070078int cap_settime(struct timespec *ts, struct timezone *tz)
79{
80 if (!capable(CAP_SYS_TIME))
81 return -EPERM;
82 return 0;
83}
84
David Howells1d045982008-11-14 10:39:24 +110085/**
86 * cap_ptrace_may_access - Determine whether the current process may access
87 * another
88 * @child: The process to be accessed
89 * @mode: The mode of attachment.
90 *
91 * Determine whether a process may access another, returning 0 if permission
92 * granted, -ve if denied.
93 */
David Howells5cd9c582008-08-14 11:37:28 +010094int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
David Howellsc69e8d92008-11-14 10:39:19 +110096 int ret = 0;
97
98 rcu_read_lock();
David Howellsd84f4f92008-11-14 10:39:23 +110099 if (!cap_issubset(__task_cred(child)->cap_permitted,
100 current_cred()->cap_permitted) &&
David Howellsc69e8d92008-11-14 10:39:19 +1100101 !capable(CAP_SYS_PTRACE))
102 ret = -EPERM;
103 rcu_read_unlock();
104 return ret;
David Howells5cd9c582008-08-14 11:37:28 +0100105}
106
David Howells1d045982008-11-14 10:39:24 +1100107/**
108 * cap_ptrace_traceme - Determine whether another process may trace the current
109 * @parent: The task proposed to be the tracer
110 *
111 * Determine whether the nominated task is permitted to trace the current
112 * process, returning 0 if permission is granted, -ve if denied.
113 */
David Howells5cd9c582008-08-14 11:37:28 +0100114int cap_ptrace_traceme(struct task_struct *parent)
115{
David Howellsc69e8d92008-11-14 10:39:19 +1100116 int ret = 0;
117
118 rcu_read_lock();
David Howellsd84f4f92008-11-14 10:39:23 +1100119 if (!cap_issubset(current_cred()->cap_permitted,
120 __task_cred(parent)->cap_permitted) &&
David Howellsc69e8d92008-11-14 10:39:19 +1100121 !has_capability(parent, CAP_SYS_PTRACE))
122 ret = -EPERM;
123 rcu_read_unlock();
124 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125}
126
David Howells1d045982008-11-14 10:39:24 +1100127/**
128 * cap_capget - Retrieve a task's capability sets
129 * @target: The task from which to retrieve the capability sets
130 * @effective: The place to record the effective set
131 * @inheritable: The place to record the inheritable set
132 * @permitted: The place to record the permitted set
133 *
134 * This function retrieves the capabilities of the nominated task and returns
135 * them to the caller.
136 */
137int cap_capget(struct task_struct *target, kernel_cap_t *effective,
138 kernel_cap_t *inheritable, kernel_cap_t *permitted)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
David Howellsc69e8d92008-11-14 10:39:19 +1100140 const struct cred *cred;
David Howellsb6dff3e2008-11-14 10:39:16 +1100141
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 /* Derived from kernel/capability.c:sys_capget. */
David Howellsc69e8d92008-11-14 10:39:19 +1100143 rcu_read_lock();
144 cred = __task_cred(target);
David Howellsb6dff3e2008-11-14 10:39:16 +1100145 *effective = cred->cap_effective;
146 *inheritable = cred->cap_inheritable;
147 *permitted = cred->cap_permitted;
David Howellsc69e8d92008-11-14 10:39:19 +1100148 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 return 0;
150}
151
David Howells1d045982008-11-14 10:39:24 +1100152/*
153 * Determine whether the inheritable capabilities are limited to the old
154 * permitted set. Returns 1 if they are limited, 0 if they are not.
155 */
Andrew Morgan72c2d582007-10-18 03:05:59 -0700156static inline int cap_inh_is_capped(void)
157{
David Howells1d045982008-11-14 10:39:24 +1100158#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
159
160 /* they are so limited unless the current task has the CAP_SETPCAP
161 * capability
Andrew Morgan72c2d582007-10-18 03:05:59 -0700162 */
David Howells1d045982008-11-14 10:39:24 +1100163 if (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
164 return 0;
165#endif
166 return 1;
Andrew Morgan72c2d582007-10-18 03:05:59 -0700167}
168
David Howells1d045982008-11-14 10:39:24 +1100169/**
170 * cap_capset - Validate and apply proposed changes to current's capabilities
171 * @new: The proposed new credentials; alterations should be made here
172 * @old: The current task's current credentials
173 * @effective: A pointer to the proposed new effective capabilities set
174 * @inheritable: A pointer to the proposed new inheritable capabilities set
175 * @permitted: A pointer to the proposed new permitted capabilities set
176 *
177 * This function validates and applies a proposed mass change to the current
178 * process's capability sets. The changes are made to the proposed new
179 * credentials, and assuming no error, will be committed by the caller of LSM.
180 */
David Howellsd84f4f92008-11-14 10:39:23 +1100181int cap_capset(struct cred *new,
182 const struct cred *old,
183 const kernel_cap_t *effective,
184 const kernel_cap_t *inheritable,
185 const kernel_cap_t *permitted)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186{
David Howellsd84f4f92008-11-14 10:39:23 +1100187 if (cap_inh_is_capped() &&
188 !cap_issubset(*inheritable,
189 cap_combine(old->cap_inheritable,
190 old->cap_permitted)))
Andrew Morgan72c2d582007-10-18 03:05:59 -0700191 /* incapable of using this inheritable set */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 return -EPERM;
David Howellsd84f4f92008-11-14 10:39:23 +1100193
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800194 if (!cap_issubset(*inheritable,
David Howellsd84f4f92008-11-14 10:39:23 +1100195 cap_combine(old->cap_inheritable,
196 old->cap_bset)))
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800197 /* no new pI capabilities outside bounding set */
198 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
200 /* verify restrictions on target's new Permitted set */
David Howellsd84f4f92008-11-14 10:39:23 +1100201 if (!cap_issubset(*permitted, old->cap_permitted))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
David Howellsd84f4f92008-11-14 10:39:23 +1100205 if (!cap_issubset(*effective, *permitted))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
David Howellsd84f4f92008-11-14 10:39:23 +1100208 new->cap_effective = *effective;
209 new->cap_inheritable = *inheritable;
210 new->cap_permitted = *permitted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 return 0;
212}
213
David Howells1d045982008-11-14 10:39:24 +1100214/*
215 * Clear proposed capability sets for execve().
216 */
Serge E. Hallynb5376772007-10-16 23:31:36 -0700217static inline void bprm_clear_caps(struct linux_binprm *bprm)
218{
David Howellsa6f76f22008-11-14 10:39:24 +1100219 cap_clear(bprm->cred->cap_permitted);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700220 bprm->cap_effective = false;
221}
222
223#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
224
David Howells1d045982008-11-14 10:39:24 +1100225/**
226 * cap_inode_need_killpriv - Determine if inode change affects privileges
227 * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
228 *
229 * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
230 * affects the security markings on that inode, and if it is, should
231 * inode_killpriv() be invoked or the change rejected?
232 *
233 * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
234 * -ve to deny the change.
235 */
Serge E. Hallynb5376772007-10-16 23:31:36 -0700236int cap_inode_need_killpriv(struct dentry *dentry)
237{
238 struct inode *inode = dentry->d_inode;
239 int error;
240
241 if (!inode->i_op || !inode->i_op->getxattr)
242 return 0;
243
244 error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
245 if (error <= 0)
246 return 0;
247 return 1;
248}
249
David Howells1d045982008-11-14 10:39:24 +1100250/**
251 * cap_inode_killpriv - Erase the security markings on an inode
252 * @dentry: The inode/dentry to alter
253 *
254 * Erase the privilege-enhancing security markings on an inode.
255 *
256 * Returns 0 if successful, -ve on error.
257 */
Serge E. Hallynb5376772007-10-16 23:31:36 -0700258int cap_inode_killpriv(struct dentry *dentry)
259{
260 struct inode *inode = dentry->d_inode;
261
262 if (!inode->i_op || !inode->i_op->removexattr)
263 return 0;
264
265 return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
266}
267
David Howells1d045982008-11-14 10:39:24 +1100268/*
269 * Calculate the new process capability sets from the capability sets attached
270 * to a file.
271 */
Eric Parisc0b00442008-11-11 21:48:10 +1100272static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
David Howellsa6f76f22008-11-14 10:39:24 +1100273 struct linux_binprm *bprm,
274 bool *effective)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700275{
David Howellsa6f76f22008-11-14 10:39:24 +1100276 struct cred *new = bprm->cred;
Eric Parisc0b00442008-11-11 21:48:10 +1100277 unsigned i;
278 int ret = 0;
279
280 if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
David Howellsa6f76f22008-11-14 10:39:24 +1100281 *effective = true;
Eric Parisc0b00442008-11-11 21:48:10 +1100282
283 CAP_FOR_EACH_U32(i) {
284 __u32 permitted = caps->permitted.cap[i];
285 __u32 inheritable = caps->inheritable.cap[i];
286
287 /*
288 * pP' = (X & fP) | (pI & fI)
289 */
David Howellsa6f76f22008-11-14 10:39:24 +1100290 new->cap_permitted.cap[i] =
291 (new->cap_bset.cap[i] & permitted) |
292 (new->cap_inheritable.cap[i] & inheritable);
Eric Parisc0b00442008-11-11 21:48:10 +1100293
David Howellsa6f76f22008-11-14 10:39:24 +1100294 if (permitted & ~new->cap_permitted.cap[i])
295 /* insufficient to execute correctly */
Eric Parisc0b00442008-11-11 21:48:10 +1100296 ret = -EPERM;
Eric Parisc0b00442008-11-11 21:48:10 +1100297 }
298
299 /*
300 * For legacy apps, with no internal support for recognizing they
301 * do not have enough capabilities, we return an error if they are
302 * missing some "forced" (aka file-permitted) capabilities.
303 */
David Howellsa6f76f22008-11-14 10:39:24 +1100304 return *effective ? ret : 0;
Eric Parisc0b00442008-11-11 21:48:10 +1100305}
306
David Howells1d045982008-11-14 10:39:24 +1100307/*
308 * Extract the on-exec-apply capability sets for an executable file.
309 */
Eric Parisc0b00442008-11-11 21:48:10 +1100310int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
311{
312 struct inode *inode = dentry->d_inode;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700313 __u32 magic_etc;
Andrew Morgane338d262008-02-04 22:29:42 -0800314 unsigned tocopy, i;
Eric Parisc0b00442008-11-11 21:48:10 +1100315 int size;
316 struct vfs_cap_data caps;
317
318 memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
319
320 if (!inode || !inode->i_op || !inode->i_op->getxattr)
321 return -ENODATA;
322
323 size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
324 XATTR_CAPS_SZ);
David Howellsa6f76f22008-11-14 10:39:24 +1100325 if (size == -ENODATA || size == -EOPNOTSUPP)
Eric Parisc0b00442008-11-11 21:48:10 +1100326 /* no data, that's ok */
327 return -ENODATA;
Eric Parisc0b00442008-11-11 21:48:10 +1100328 if (size < 0)
329 return size;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700330
Andrew Morgane338d262008-02-04 22:29:42 -0800331 if (size < sizeof(magic_etc))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700332 return -EINVAL;
333
Eric Parisc0b00442008-11-11 21:48:10 +1100334 cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700335
David Howellsa6f76f22008-11-14 10:39:24 +1100336 switch (magic_etc & VFS_CAP_REVISION_MASK) {
Andrew Morgane338d262008-02-04 22:29:42 -0800337 case VFS_CAP_REVISION_1:
338 if (size != XATTR_CAPS_SZ_1)
339 return -EINVAL;
340 tocopy = VFS_CAP_U32_1;
341 break;
342 case VFS_CAP_REVISION_2:
343 if (size != XATTR_CAPS_SZ_2)
344 return -EINVAL;
345 tocopy = VFS_CAP_U32_2;
346 break;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700347 default:
348 return -EINVAL;
349 }
Andrew Morgane338d262008-02-04 22:29:42 -0800350
Andrew G. Morgan5459c162008-07-23 21:28:24 -0700351 CAP_FOR_EACH_U32(i) {
Eric Parisc0b00442008-11-11 21:48:10 +1100352 if (i >= tocopy)
353 break;
354 cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
355 cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
Andrew Morgane338d262008-02-04 22:29:42 -0800356 }
David Howellsa6f76f22008-11-14 10:39:24 +1100357
Eric Parisc0b00442008-11-11 21:48:10 +1100358 return 0;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700359}
360
David Howells1d045982008-11-14 10:39:24 +1100361/*
362 * Attempt to get the on-exec apply capability sets for an executable file from
363 * its xattrs and, if present, apply them to the proposed credentials being
364 * constructed by execve().
365 */
David Howellsa6f76f22008-11-14 10:39:24 +1100366static int get_file_caps(struct linux_binprm *bprm, bool *effective)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700367{
368 struct dentry *dentry;
369 int rc = 0;
Eric Parisc0b00442008-11-11 21:48:10 +1100370 struct cpu_vfs_cap_data vcaps;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700371
Serge Hallyn3318a382008-10-30 11:52:23 -0500372 bprm_clear_caps(bprm);
373
Serge E. Hallyn1f29fae2008-11-05 16:08:52 -0600374 if (!file_caps_enabled)
375 return 0;
376
Serge Hallyn3318a382008-10-30 11:52:23 -0500377 if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700378 return 0;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700379
380 dentry = dget(bprm->file->f_dentry);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700381
Eric Parisc0b00442008-11-11 21:48:10 +1100382 rc = get_vfs_caps_from_disk(dentry, &vcaps);
383 if (rc < 0) {
384 if (rc == -EINVAL)
385 printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
386 __func__, rc, bprm->filename);
387 else if (rc == -ENODATA)
388 rc = 0;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700389 goto out;
390 }
Serge E. Hallynb5376772007-10-16 23:31:36 -0700391
David Howellsa6f76f22008-11-14 10:39:24 +1100392 rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective);
393 if (rc == -EINVAL)
394 printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
395 __func__, rc, bprm->filename);
Serge E. Hallynb5376772007-10-16 23:31:36 -0700396
397out:
398 dput(dentry);
399 if (rc)
400 bprm_clear_caps(bprm);
401
402 return rc;
403}
404
405#else
406int cap_inode_need_killpriv(struct dentry *dentry)
407{
408 return 0;
409}
410
411int cap_inode_killpriv(struct dentry *dentry)
412{
413 return 0;
414}
415
Eric Parise50a9062008-11-13 18:37:25 -0500416int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
417{
418 memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
419 return -ENODATA;
420}
421
David Howellsa6f76f22008-11-14 10:39:24 +1100422static inline int get_file_caps(struct linux_binprm *bprm, bool *effective)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700423{
424 bprm_clear_caps(bprm);
425 return 0;
426}
427#endif
428
David Howellsa6f76f22008-11-14 10:39:24 +1100429/*
David Howells1d045982008-11-14 10:39:24 +1100430 * Determine whether a exec'ing process's new permitted capabilities should be
431 * limited to just what it already has.
432 *
433 * This prevents processes that are being ptraced from gaining access to
434 * CAP_SETPCAP, unless the process they're tracing already has it, and the
435 * binary they're executing has filecaps that elevate it.
436 *
437 * Returns 1 if they should be limited, 0 if they are not.
438 */
439static inline int cap_limit_ptraced_target(void)
440{
441#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
442 if (capable(CAP_SETPCAP))
443 return 0;
444#endif
445 return 1;
446}
447
448/**
449 * cap_bprm_set_creds - Set up the proposed credentials for execve().
450 * @bprm: The execution parameters, including the proposed creds
451 *
452 * Set up the proposed credentials for a new execution context being
453 * constructed by execve(). The proposed creds in @bprm->cred is altered,
454 * which won't take effect immediately. Returns 0 if successful, -ve on error.
David Howellsa6f76f22008-11-14 10:39:24 +1100455 */
456int cap_bprm_set_creds(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457{
David Howellsa6f76f22008-11-14 10:39:24 +1100458 const struct cred *old = current_cred();
459 struct cred *new = bprm->cred;
460 bool effective;
Serge E. Hallynb5376772007-10-16 23:31:36 -0700461 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
David Howellsa6f76f22008-11-14 10:39:24 +1100463 effective = false;
464 ret = get_file_caps(bprm, &effective);
465 if (ret < 0)
466 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
Andrew G. Morgan5459c162008-07-23 21:28:24 -0700468 if (!issecure(SECURE_NOROOT)) {
469 /*
470 * To support inheritance of root-permissions and suid-root
471 * executables under compatibility mode, we override the
472 * capability sets for the file.
473 *
David Howellsa6f76f22008-11-14 10:39:24 +1100474 * If only the real uid is 0, we do not set the effective bit.
Andrew G. Morgan5459c162008-07-23 21:28:24 -0700475 */
David Howellsa6f76f22008-11-14 10:39:24 +1100476 if (new->euid == 0 || new->uid == 0) {
Andrew G. Morgan5459c162008-07-23 21:28:24 -0700477 /* pP' = (cap_bset & ~0) | (pI & ~0) */
David Howellsa6f76f22008-11-14 10:39:24 +1100478 new->cap_permitted = cap_combine(old->cap_bset,
479 old->cap_inheritable);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 }
David Howellsa6f76f22008-11-14 10:39:24 +1100481 if (new->euid == 0)
482 effective = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 }
Serge E. Hallynb5376772007-10-16 23:31:36 -0700484
David Howellsa6f76f22008-11-14 10:39:24 +1100485 /* Don't let someone trace a set[ug]id/setpcap binary with the revised
486 * credentials unless they have the appropriate permit
487 */
488 if ((new->euid != old->uid ||
489 new->egid != old->gid ||
490 !cap_issubset(new->cap_permitted, old->cap_permitted)) &&
491 bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
492 /* downgrade; they get no more than they had, and maybe less */
493 if (!capable(CAP_SETUID)) {
494 new->euid = new->uid;
495 new->egid = new->gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 }
David Howellsa6f76f22008-11-14 10:39:24 +1100497 if (cap_limit_ptraced_target())
498 new->cap_permitted = cap_intersect(new->cap_permitted,
499 old->cap_permitted);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 }
501
David Howellsa6f76f22008-11-14 10:39:24 +1100502 new->suid = new->fsuid = new->euid;
503 new->sgid = new->fsgid = new->egid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
David Howellsa6f76f22008-11-14 10:39:24 +1100505 /* For init, we want to retain the capabilities set in the initial
506 * task. Thus we skip the usual capability rules
507 */
Serge E. Hallynb460cbc2007-10-18 23:39:52 -0700508 if (!is_global_init(current)) {
David Howellsa6f76f22008-11-14 10:39:24 +1100509 if (effective)
510 new->cap_effective = new->cap_permitted;
Andrew Morgane338d262008-02-04 22:29:42 -0800511 else
David Howellsd84f4f92008-11-14 10:39:23 +1100512 cap_clear(new->cap_effective);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 }
David Howellsa6f76f22008-11-14 10:39:24 +1100514 bprm->cap_effective = effective;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
Eric Paris3fc689e2008-11-11 21:48:18 +1100516 /*
517 * Audit candidate if current->cap_effective is set
518 *
519 * We do not bother to audit if 3 things are true:
520 * 1) cap_effective has all caps
521 * 2) we are root
522 * 3) root is supposed to have all caps (SECURE_NOROOT)
523 * Since this is just a normal root execing a process.
524 *
525 * Number 1 above might fail if you don't have a full bset, but I think
526 * that is interesting information to audit.
527 */
David Howellsd84f4f92008-11-14 10:39:23 +1100528 if (!cap_isclear(new->cap_effective)) {
529 if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
David Howellsa6f76f22008-11-14 10:39:24 +1100530 new->euid != 0 || new->uid != 0 ||
531 issecure(SECURE_NOROOT)) {
532 ret = audit_log_bprm_fcaps(bprm, new, old);
533 if (ret < 0)
534 return ret;
535 }
Eric Paris3fc689e2008-11-11 21:48:18 +1100536 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
David Howellsd84f4f92008-11-14 10:39:23 +1100538 new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
David Howellsa6f76f22008-11-14 10:39:24 +1100539 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540}
541
David Howells1d045982008-11-14 10:39:24 +1100542/**
543 * cap_bprm_secureexec - Determine whether a secure execution is required
544 * @bprm: The execution parameters
545 *
546 * Determine whether a secure execution is required, return 1 if it is, and 0
547 * if it is not.
548 *
549 * The credentials have been committed by this point, and so are no longer
550 * available through @bprm->cred.
David Howellsa6f76f22008-11-14 10:39:24 +1100551 */
552int cap_bprm_secureexec(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553{
David Howellsc69e8d92008-11-14 10:39:19 +1100554 const struct cred *cred = current_cred();
David Howellsb6dff3e2008-11-14 10:39:16 +1100555
556 if (cred->uid != 0) {
Serge E. Hallynb5376772007-10-16 23:31:36 -0700557 if (bprm->cap_effective)
558 return 1;
David Howellsa6f76f22008-11-14 10:39:24 +1100559 if (!cap_isclear(cred->cap_permitted))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700560 return 1;
561 }
562
David Howellsb6dff3e2008-11-14 10:39:16 +1100563 return (cred->euid != cred->uid ||
564 cred->egid != cred->gid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565}
566
David Howells1d045982008-11-14 10:39:24 +1100567/**
568 * cap_inode_setxattr - Determine whether an xattr may be altered
569 * @dentry: The inode/dentry being altered
570 * @name: The name of the xattr to be changed
571 * @value: The value that the xattr will be changed to
572 * @size: The size of value
573 * @flags: The replacement flag
574 *
575 * Determine whether an xattr may be altered or set on an inode, returning 0 if
576 * permission is granted, -ve if denied.
577 *
578 * This is used to make sure security xattrs don't get updated or set by those
579 * who aren't privileged to do so.
580 */
David Howells8f0cfa52008-04-29 00:59:41 -0700581int cap_inode_setxattr(struct dentry *dentry, const char *name,
582 const void *value, size_t size, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700584 if (!strcmp(name, XATTR_NAME_CAPS)) {
585 if (!capable(CAP_SETFCAP))
586 return -EPERM;
587 return 0;
David Howells1d045982008-11-14 10:39:24 +1100588 }
589
590 if (!strncmp(name, XATTR_SECURITY_PREFIX,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
592 !capable(CAP_SYS_ADMIN))
593 return -EPERM;
594 return 0;
595}
596
David Howells1d045982008-11-14 10:39:24 +1100597/**
598 * cap_inode_removexattr - Determine whether an xattr may be removed
599 * @dentry: The inode/dentry being altered
600 * @name: The name of the xattr to be changed
601 *
602 * Determine whether an xattr may be removed from an inode, returning 0 if
603 * permission is granted, -ve if denied.
604 *
605 * This is used to make sure security xattrs don't get removed by those who
606 * aren't privileged to remove them.
607 */
David Howells8f0cfa52008-04-29 00:59:41 -0700608int cap_inode_removexattr(struct dentry *dentry, const char *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609{
Serge E. Hallynb5376772007-10-16 23:31:36 -0700610 if (!strcmp(name, XATTR_NAME_CAPS)) {
611 if (!capable(CAP_SETFCAP))
612 return -EPERM;
613 return 0;
David Howells1d045982008-11-14 10:39:24 +1100614 }
615
616 if (!strncmp(name, XATTR_SECURITY_PREFIX,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 sizeof(XATTR_SECURITY_PREFIX) - 1) &&
618 !capable(CAP_SYS_ADMIN))
619 return -EPERM;
620 return 0;
621}
622
David Howellsa6f76f22008-11-14 10:39:24 +1100623/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 * cap_emulate_setxuid() fixes the effective / permitted capabilities of
625 * a process after a call to setuid, setreuid, or setresuid.
626 *
627 * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
628 * {r,e,s}uid != 0, the permitted and effective capabilities are
629 * cleared.
630 *
631 * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
632 * capabilities of the process are cleared.
633 *
634 * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
635 * capabilities are set to the permitted capabilities.
636 *
David Howellsa6f76f22008-11-14 10:39:24 +1100637 * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 * never happen.
639 *
David Howellsa6f76f22008-11-14 10:39:24 +1100640 * -astor
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 *
642 * cevans - New behaviour, Oct '99
643 * A process may, via prctl(), elect to keep its capabilities when it
644 * calls setuid() and switches away from uid==0. Both permitted and
645 * effective sets will be retained.
646 * Without this change, it was impossible for a daemon to drop only some
647 * of its privilege. The call to setuid(!=0) would drop all privileges!
648 * Keeping uid 0 is not an option because uid 0 owns too many vital
649 * files..
650 * Thanks to Olaf Kirch and Peter Benie for spotting this.
651 */
David Howellsd84f4f92008-11-14 10:39:23 +1100652static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653{
David Howellsd84f4f92008-11-14 10:39:23 +1100654 if ((old->uid == 0 || old->euid == 0 || old->suid == 0) &&
655 (new->uid != 0 && new->euid != 0 && new->suid != 0) &&
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700656 !issecure(SECURE_KEEP_CAPS)) {
David Howellsd84f4f92008-11-14 10:39:23 +1100657 cap_clear(new->cap_permitted);
658 cap_clear(new->cap_effective);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 }
David Howellsd84f4f92008-11-14 10:39:23 +1100660 if (old->euid == 0 && new->euid != 0)
661 cap_clear(new->cap_effective);
662 if (old->euid != 0 && new->euid == 0)
663 new->cap_effective = new->cap_permitted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664}
665
David Howells1d045982008-11-14 10:39:24 +1100666/**
667 * cap_task_fix_setuid - Fix up the results of setuid() call
668 * @new: The proposed credentials
669 * @old: The current task's current credentials
670 * @flags: Indications of what has changed
671 *
672 * Fix up the results of setuid() call before the credential changes are
673 * actually applied, returning 0 to grant the changes, -ve to deny them.
674 */
David Howellsd84f4f92008-11-14 10:39:23 +1100675int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676{
677 switch (flags) {
678 case LSM_SETID_RE:
679 case LSM_SETID_ID:
680 case LSM_SETID_RES:
David Howells1d045982008-11-14 10:39:24 +1100681 /* juggle the capabilities to follow [RES]UID changes unless
682 * otherwise suppressed */
David Howellsd84f4f92008-11-14 10:39:23 +1100683 if (!issecure(SECURE_NO_SETUID_FIXUP))
684 cap_emulate_setxuid(new, old);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686
David Howells1d045982008-11-14 10:39:24 +1100687 case LSM_SETID_FS:
688 /* juggle the capabilties to follow FSUID changes, unless
689 * otherwise suppressed
690 *
David Howellsd84f4f92008-11-14 10:39:23 +1100691 * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
692 * if not, we might be a bit too harsh here.
693 */
694 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
David Howells1d045982008-11-14 10:39:24 +1100695 if (old->fsuid == 0 && new->fsuid != 0)
David Howellsd84f4f92008-11-14 10:39:23 +1100696 new->cap_effective =
697 cap_drop_fs_set(new->cap_effective);
David Howells1d045982008-11-14 10:39:24 +1100698
699 if (old->fsuid != 0 && new->fsuid == 0)
David Howellsd84f4f92008-11-14 10:39:23 +1100700 new->cap_effective =
701 cap_raise_fs_set(new->cap_effective,
702 new->cap_permitted);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 }
David Howellsd84f4f92008-11-14 10:39:23 +1100704 break;
David Howells1d045982008-11-14 10:39:24 +1100705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 default:
707 return -EINVAL;
708 }
709
710 return 0;
711}
712
Serge E. Hallynb5376772007-10-16 23:31:36 -0700713#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
714/*
715 * Rationale: code calling task_setscheduler, task_setioprio, and
716 * task_setnice, assumes that
717 * . if capable(cap_sys_nice), then those actions should be allowed
718 * . if not capable(cap_sys_nice), but acting on your own processes,
719 * then those actions should be allowed
720 * This is insufficient now since you can call code without suid, but
721 * yet with increased caps.
722 * So we check for increased caps on the target process.
723 */
Serge E. Hallynde45e802008-09-26 22:27:47 -0400724static int cap_safe_nice(struct task_struct *p)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700725{
David Howellsc69e8d92008-11-14 10:39:19 +1100726 int is_subset;
727
728 rcu_read_lock();
729 is_subset = cap_issubset(__task_cred(p)->cap_permitted,
730 current_cred()->cap_permitted);
731 rcu_read_unlock();
732
733 if (!is_subset && !capable(CAP_SYS_NICE))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700734 return -EPERM;
735 return 0;
736}
737
David Howells1d045982008-11-14 10:39:24 +1100738/**
739 * cap_task_setscheduler - Detemine if scheduler policy change is permitted
740 * @p: The task to affect
741 * @policy: The policy to effect
742 * @lp: The parameters to the scheduling policy
743 *
744 * Detemine if the requested scheduler policy change is permitted for the
745 * specified task, returning 0 if permission is granted, -ve if denied.
746 */
747int cap_task_setscheduler(struct task_struct *p, int policy,
Serge E. Hallynb5376772007-10-16 23:31:36 -0700748 struct sched_param *lp)
749{
750 return cap_safe_nice(p);
751}
752
David Howells1d045982008-11-14 10:39:24 +1100753/**
754 * cap_task_ioprio - Detemine if I/O priority change is permitted
755 * @p: The task to affect
756 * @ioprio: The I/O priority to set
757 *
758 * Detemine if the requested I/O priority change is permitted for the specified
759 * task, returning 0 if permission is granted, -ve if denied.
760 */
761int cap_task_setioprio(struct task_struct *p, int ioprio)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700762{
763 return cap_safe_nice(p);
764}
765
David Howells1d045982008-11-14 10:39:24 +1100766/**
767 * cap_task_ioprio - Detemine if task priority change is permitted
768 * @p: The task to affect
769 * @nice: The nice value to set
770 *
771 * Detemine if the requested task priority change is permitted for the
772 * specified task, returning 0 if permission is granted, -ve if denied.
773 */
774int cap_task_setnice(struct task_struct *p, int nice)
Serge E. Hallynb5376772007-10-16 23:31:36 -0700775{
776 return cap_safe_nice(p);
777}
778
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800779/*
David Howells1d045982008-11-14 10:39:24 +1100780 * Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
781 * the current task's bounding set. Returns 0 on success, -ve on error.
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800782 */
David Howellsd84f4f92008-11-14 10:39:23 +1100783static long cap_prctl_drop(struct cred *new, unsigned long cap)
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800784{
785 if (!capable(CAP_SETPCAP))
786 return -EPERM;
787 if (!cap_valid(cap))
788 return -EINVAL;
David Howellsd84f4f92008-11-14 10:39:23 +1100789
790 cap_lower(new->cap_bset, cap);
Serge E. Hallyn3b7391d2008-02-04 22:29:45 -0800791 return 0;
792}
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700793
Serge E. Hallynb5376772007-10-16 23:31:36 -0700794#else
795int cap_task_setscheduler (struct task_struct *p, int policy,
796 struct sched_param *lp)
797{
798 return 0;
799}
800int cap_task_setioprio (struct task_struct *p, int ioprio)
801{
802 return 0;
803}
804int cap_task_setnice (struct task_struct *p, int nice)
805{
806 return 0;
807}
Serge E. Hallynb5376772007-10-16 23:31:36 -0700808#endif
809
David Howells1d045982008-11-14 10:39:24 +1100810/**
811 * cap_task_prctl - Implement process control functions for this security module
812 * @option: The process control function requested
813 * @arg2, @arg3, @arg4, @arg5: The argument data for this function
814 *
815 * Allow process control functions (sys_prctl()) to alter capabilities; may
816 * also deny access to other functions not otherwise implemented here.
817 *
818 * Returns 0 or +ve on success, -ENOSYS if this function is not implemented
819 * here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
820 * modules will consider performing the function.
821 */
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700822int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
David Howellsd84f4f92008-11-14 10:39:23 +1100823 unsigned long arg4, unsigned long arg5)
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700824{
David Howellsd84f4f92008-11-14 10:39:23 +1100825 struct cred *new;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700826 long error = 0;
827
David Howellsd84f4f92008-11-14 10:39:23 +1100828 new = prepare_creds();
829 if (!new)
830 return -ENOMEM;
831
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700832 switch (option) {
833 case PR_CAPBSET_READ:
David Howellsd84f4f92008-11-14 10:39:23 +1100834 error = -EINVAL;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700835 if (!cap_valid(arg2))
David Howellsd84f4f92008-11-14 10:39:23 +1100836 goto error;
837 error = !!cap_raised(new->cap_bset, arg2);
838 goto no_change;
839
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700840#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
841 case PR_CAPBSET_DROP:
David Howellsd84f4f92008-11-14 10:39:23 +1100842 error = cap_prctl_drop(new, arg2);
843 if (error < 0)
844 goto error;
845 goto changed;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700846
847 /*
848 * The next four prctl's remain to assist with transitioning a
849 * system from legacy UID=0 based privilege (when filesystem
850 * capabilities are not in use) to a system using filesystem
851 * capabilities only - as the POSIX.1e draft intended.
852 *
853 * Note:
854 *
855 * PR_SET_SECUREBITS =
856 * issecure_mask(SECURE_KEEP_CAPS_LOCKED)
857 * | issecure_mask(SECURE_NOROOT)
858 * | issecure_mask(SECURE_NOROOT_LOCKED)
859 * | issecure_mask(SECURE_NO_SETUID_FIXUP)
860 * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
861 *
862 * will ensure that the current process and all of its
863 * children will be locked into a pure
864 * capability-based-privilege environment.
865 */
866 case PR_SET_SECUREBITS:
David Howellsd84f4f92008-11-14 10:39:23 +1100867 error = -EPERM;
868 if ((((new->securebits & SECURE_ALL_LOCKS) >> 1)
869 & (new->securebits ^ arg2)) /*[1]*/
870 || ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
871 || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
872 || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0) /*[4]*/
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700873 /*
874 * [1] no changing of bits that are locked
875 * [2] no unlocking of locks
876 * [3] no setting of unsupported bits
877 * [4] doing anything requires privilege (go read about
878 * the "sendmail capabilities bug")
879 */
David Howellsd84f4f92008-11-14 10:39:23 +1100880 )
881 /* cannot change a locked bit */
882 goto error;
883 new->securebits = arg2;
884 goto changed;
885
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700886 case PR_GET_SECUREBITS:
David Howellsd84f4f92008-11-14 10:39:23 +1100887 error = new->securebits;
888 goto no_change;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700889
890#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
891
892 case PR_GET_KEEPCAPS:
893 if (issecure(SECURE_KEEP_CAPS))
894 error = 1;
David Howellsd84f4f92008-11-14 10:39:23 +1100895 goto no_change;
896
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700897 case PR_SET_KEEPCAPS:
David Howellsd84f4f92008-11-14 10:39:23 +1100898 error = -EINVAL;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700899 if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
David Howellsd84f4f92008-11-14 10:39:23 +1100900 goto error;
901 error = -EPERM;
902 if (issecure(SECURE_KEEP_CAPS_LOCKED))
903 goto error;
904 if (arg2)
905 new->securebits |= issecure_mask(SECURE_KEEP_CAPS);
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700906 else
David Howellsd84f4f92008-11-14 10:39:23 +1100907 new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
908 goto changed;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700909
910 default:
911 /* No functionality available - continue with default */
David Howellsd84f4f92008-11-14 10:39:23 +1100912 error = -ENOSYS;
913 goto error;
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700914 }
915
916 /* Functionality provided */
David Howellsd84f4f92008-11-14 10:39:23 +1100917changed:
918 return commit_creds(new);
Andrew G. Morgan3898b1b2008-04-28 02:13:40 -0700919
David Howellsd84f4f92008-11-14 10:39:23 +1100920no_change:
921 error = 0;
922error:
923 abort_creds(new);
924 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925}
926
David Howells1d045982008-11-14 10:39:24 +1100927/**
928 * cap_syslog - Determine whether syslog function is permitted
929 * @type: Function requested
930 *
931 * Determine whether the current process is permitted to use a particular
932 * syslog function, returning 0 if permission is granted, -ve if not.
933 */
934int cap_syslog(int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935{
936 if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
937 return -EPERM;
938 return 0;
939}
940
David Howells1d045982008-11-14 10:39:24 +1100941/**
942 * cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
943 * @mm: The VM space in which the new mapping is to be made
944 * @pages: The size of the mapping
945 *
946 * Determine whether the allocation of a new virtual mapping by the current
947 * task is permitted, returning 0 if permission is granted, -ve if not.
948 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700949int cap_vm_enough_memory(struct mm_struct *mm, long pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950{
951 int cap_sys_admin = 0;
952
Eric Paris06112162008-11-11 22:02:50 +1100953 if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 cap_sys_admin = 1;
Alan Cox34b4e4a2007-08-22 14:01:28 -0700955 return __vm_enough_memory(mm, pages, cap_sys_admin);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956}