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-rw-r--r--security/commoncap.c152
1 files changed, 76 insertions, 76 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index b5419273f92..51dfa11e8e5 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -167,7 +167,7 @@ int cap_capset(struct cred *new,
static inline void bprm_clear_caps(struct linux_binprm *bprm)
{
- cap_clear(bprm->cap_post_exec_permitted);
+ cap_clear(bprm->cred->cap_permitted);
bprm->cap_effective = false;
}
@@ -198,15 +198,15 @@ int cap_inode_killpriv(struct dentry *dentry)
}
static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
- struct linux_binprm *bprm)
+ struct linux_binprm *bprm,
+ bool *effective)
{
+ struct cred *new = bprm->cred;
unsigned i;
int ret = 0;
if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
- bprm->cap_effective = true;
- else
- bprm->cap_effective = false;
+ *effective = true;
CAP_FOR_EACH_U32(i) {
__u32 permitted = caps->permitted.cap[i];
@@ -215,16 +215,13 @@ static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
/*
* pP' = (X & fP) | (pI & fI)
*/
- bprm->cap_post_exec_permitted.cap[i] =
- (current->cred->cap_bset.cap[i] & permitted) |
- (current->cred->cap_inheritable.cap[i] & inheritable);
+ new->cap_permitted.cap[i] =
+ (new->cap_bset.cap[i] & permitted) |
+ (new->cap_inheritable.cap[i] & inheritable);
- if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) {
- /*
- * insufficient to execute correctly
- */
+ if (permitted & ~new->cap_permitted.cap[i])
+ /* insufficient to execute correctly */
ret = -EPERM;
- }
}
/*
@@ -232,7 +229,7 @@ static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
* do not have enough capabilities, we return an error if they are
* missing some "forced" (aka file-permitted) capabilities.
*/
- return bprm->cap_effective ? ret : 0;
+ return *effective ? ret : 0;
}
int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
@@ -250,10 +247,9 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
XATTR_CAPS_SZ);
- if (size == -ENODATA || size == -EOPNOTSUPP) {
+ if (size == -ENODATA || size == -EOPNOTSUPP)
/* no data, that's ok */
return -ENODATA;
- }
if (size < 0)
return size;
@@ -262,7 +258,7 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
- switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
+ switch (magic_etc & VFS_CAP_REVISION_MASK) {
case VFS_CAP_REVISION_1:
if (size != XATTR_CAPS_SZ_1)
return -EINVAL;
@@ -283,11 +279,12 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
}
+
return 0;
}
/* Locate any VFS capabilities: */
-static int get_file_caps(struct linux_binprm *bprm)
+static int get_file_caps(struct linux_binprm *bprm, bool *effective)
{
struct dentry *dentry;
int rc = 0;
@@ -313,7 +310,10 @@ static int get_file_caps(struct linux_binprm *bprm)
goto out;
}
- rc = bprm_caps_from_vfs_caps(&vcaps, bprm);
+ rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective);
+ if (rc == -EINVAL)
+ printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
+ __func__, rc, bprm->filename);
out:
dput(dentry);
@@ -334,18 +334,27 @@ int cap_inode_killpriv(struct dentry *dentry)
return 0;
}
-static inline int get_file_caps(struct linux_binprm *bprm)
+static inline int get_file_caps(struct linux_binprm *bprm, bool *effective)
{
bprm_clear_caps(bprm);
return 0;
}
#endif
-int cap_bprm_set_security (struct linux_binprm *bprm)
+/*
+ * set up the new credentials for an exec'd task
+ */
+int cap_bprm_set_creds(struct linux_binprm *bprm)
{
+ const struct cred *old = current_cred();
+ struct cred *new = bprm->cred;
+ bool effective;
int ret;
- ret = get_file_caps(bprm);
+ effective = false;
+ ret = get_file_caps(bprm, &effective);
+ if (ret < 0)
+ return ret;
if (!issecure(SECURE_NOROOT)) {
/*
@@ -353,63 +362,47 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
* executables under compatibility mode, we override the
* capability sets for the file.
*
- * If only the real uid is 0, we do not set the effective
- * bit.
+ * If only the real uid is 0, we do not set the effective bit.
*/
- if (bprm->e_uid == 0 || current_uid() == 0) {
+ if (new->euid == 0 || new->uid == 0) {
/* pP' = (cap_bset & ~0) | (pI & ~0) */
- bprm->cap_post_exec_permitted = cap_combine(
- current->cred->cap_bset,
- current->cred->cap_inheritable);
- bprm->cap_effective = (bprm->e_uid == 0);
- ret = 0;
+ new->cap_permitted = cap_combine(old->cap_bset,
+ old->cap_inheritable);
}
+ if (new->euid == 0)
+ effective = true;
}
- return ret;
-}
-
-int cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
-{
- const struct cred *old = current_cred();
- struct cred *new;
-
- new = prepare_creds();
- if (!new)
- return -ENOMEM;
-
- if (bprm->e_uid != old->uid || bprm->e_gid != old->gid ||
- !cap_issubset(bprm->cap_post_exec_permitted,
- old->cap_permitted)) {
- set_dumpable(current->mm, suid_dumpable);
- current->pdeath_signal = 0;
-
- if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
- if (!capable(CAP_SETUID)) {
- bprm->e_uid = old->uid;
- bprm->e_gid = old->gid;
- }
- if (cap_limit_ptraced_target()) {
- bprm->cap_post_exec_permitted = cap_intersect(
- bprm->cap_post_exec_permitted,
- new->cap_permitted);
- }
+ /* Don't let someone trace a set[ug]id/setpcap binary with the revised
+ * credentials unless they have the appropriate permit
+ */
+ if ((new->euid != old->uid ||
+ new->egid != old->gid ||
+ !cap_issubset(new->cap_permitted, old->cap_permitted)) &&
+ bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
+ /* downgrade; they get no more than they had, and maybe less */
+ if (!capable(CAP_SETUID)) {
+ new->euid = new->uid;
+ new->egid = new->gid;
}
+ if (cap_limit_ptraced_target())
+ new->cap_permitted = cap_intersect(new->cap_permitted,
+ old->cap_permitted);
}
- new->suid = new->euid = new->fsuid = bprm->e_uid;
- new->sgid = new->egid = new->fsgid = bprm->e_gid;
+ new->suid = new->fsuid = new->euid;
+ new->sgid = new->fsgid = new->egid;
- /* For init, we want to retain the capabilities set
- * in the init_task struct. Thus we skip the usual
- * capability rules */
+ /* For init, we want to retain the capabilities set in the initial
+ * task. Thus we skip the usual capability rules
+ */
if (!is_global_init(current)) {
- new->cap_permitted = bprm->cap_post_exec_permitted;
- if (bprm->cap_effective)
- new->cap_effective = bprm->cap_post_exec_permitted;
+ if (effective)
+ new->cap_effective = new->cap_permitted;
else
cap_clear(new->cap_effective);
}
+ bprm->cap_effective = effective;
/*
* Audit candidate if current->cap_effective is set
@@ -425,23 +418,31 @@ int cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
*/
if (!cap_isclear(new->cap_effective)) {
if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
- bprm->e_uid != 0 || new->uid != 0 ||
- issecure(SECURE_NOROOT))
- audit_log_bprm_fcaps(bprm, new, old);
+ new->euid != 0 || new->uid != 0 ||
+ issecure(SECURE_NOROOT)) {
+ ret = audit_log_bprm_fcaps(bprm, new, old);
+ if (ret < 0)
+ return ret;
+ }
}
new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
- return commit_creds(new);
+ return 0;
}
-int cap_bprm_secureexec (struct linux_binprm *bprm)
+/*
+ * determine whether a secure execution is required
+ * - the creds have been committed at this point, and are no longer available
+ * through bprm
+ */
+int cap_bprm_secureexec(struct linux_binprm *bprm)
{
const struct cred *cred = current_cred();
if (cred->uid != 0) {
if (bprm->cap_effective)
return 1;
- if (!cap_isclear(bprm->cap_post_exec_permitted))
+ if (!cap_isclear(cred->cap_permitted))
return 1;
}
@@ -477,7 +478,7 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
}
/* moved from kernel/sys.c. */
-/*
+/*
* cap_emulate_setxuid() fixes the effective / permitted capabilities of
* a process after a call to setuid, setreuid, or setresuid.
*
@@ -491,10 +492,10 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
* 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
* capabilities are set to the permitted capabilities.
*
- * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
+ * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
* never happen.
*
- * -astor
+ * -astor
*
* cevans - New behaviour, Oct '99
* A process may, via prctl(), elect to keep its capabilities when it
@@ -751,4 +752,3 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
cap_sys_admin = 1;
return __vm_enough_memory(mm, pages, cap_sys_admin);
}
-
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-08 15:07:23 +0000