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Diffstat (limited to 'security/commoncap.c')
-rw-r--r--security/commoncap.c265
1 files changed, 125 insertions, 140 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index 0384bf95db68..b5419273f92d 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -72,8 +72,8 @@ int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
int ret = 0;
rcu_read_lock();
- if (!cap_issubset(child->cred->cap_permitted,
- current->cred->cap_permitted) &&
+ if (!cap_issubset(__task_cred(child)->cap_permitted,
+ current_cred()->cap_permitted) &&
!capable(CAP_SYS_PTRACE))
ret = -EPERM;
rcu_read_unlock();
@@ -85,8 +85,8 @@ int cap_ptrace_traceme(struct task_struct *parent)
int ret = 0;
rcu_read_lock();
- if (!cap_issubset(current->cred->cap_permitted,
- parent->cred->cap_permitted) &&
+ if (!cap_issubset(current_cred()->cap_permitted,
+ __task_cred(parent)->cap_permitted) &&
!has_capability(parent, CAP_SYS_PTRACE))
ret = -EPERM;
rcu_read_unlock();
@@ -117,7 +117,7 @@ static inline int cap_inh_is_capped(void)
* to the old permitted set. That is, if the current task
* does *not* possess the CAP_SETPCAP capability.
*/
- return (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0);
+ return cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0;
}
static inline int cap_limit_ptraced_target(void) { return 1; }
@@ -132,52 +132,39 @@ static inline int cap_limit_ptraced_target(void)
#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
-int cap_capset_check(const kernel_cap_t *effective,
- const kernel_cap_t *inheritable,
- const kernel_cap_t *permitted)
+int cap_capset(struct cred *new,
+ const struct cred *old,
+ const kernel_cap_t *effective,
+ const kernel_cap_t *inheritable,
+ const kernel_cap_t *permitted)
{
- const struct cred *cred = current->cred;
-
- if (cap_inh_is_capped()
- && !cap_issubset(*inheritable,
- cap_combine(cred->cap_inheritable,
- cred->cap_permitted))) {
+ if (cap_inh_is_capped() &&
+ !cap_issubset(*inheritable,
+ cap_combine(old->cap_inheritable,
+ old->cap_permitted)))
/* incapable of using this inheritable set */
return -EPERM;
- }
+
if (!cap_issubset(*inheritable,
- cap_combine(cred->cap_inheritable,
- cred->cap_bset))) {
+ cap_combine(old->cap_inheritable,
+ old->cap_bset)))
/* no new pI capabilities outside bounding set */
return -EPERM;
- }
/* verify restrictions on target's new Permitted set */
- if (!cap_issubset (*permitted,
- cap_combine (cred->cap_permitted,
- cred->cap_permitted))) {
+ if (!cap_issubset(*permitted, old->cap_permitted))
return -EPERM;
- }
/* verify the _new_Effective_ is a subset of the _new_Permitted_ */
- if (!cap_issubset (*effective, *permitted)) {
+ if (!cap_issubset(*effective, *permitted))
return -EPERM;
- }
+ new->cap_effective = *effective;
+ new->cap_inheritable = *inheritable;
+ new->cap_permitted = *permitted;
return 0;
}
-void cap_capset_set(const kernel_cap_t *effective,
- const kernel_cap_t *inheritable,
- const kernel_cap_t *permitted)
-{
- struct cred *cred = current->cred;
-
- cred->cap_effective = *effective;
- cred->cap_inheritable = *inheritable;
- cred->cap_permitted = *permitted;
-}
-
static inline void bprm_clear_caps(struct linux_binprm *bprm)
{
cap_clear(bprm->cap_post_exec_permitted);
@@ -382,41 +369,46 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
return ret;
}
-void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
+int cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
{
- struct cred *cred = current->cred;
+ const struct cred *old = current_cred();
+ struct cred *new;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
- if (bprm->e_uid != cred->uid || bprm->e_gid != cred->gid ||
+ if (bprm->e_uid != old->uid || bprm->e_gid != old->gid ||
!cap_issubset(bprm->cap_post_exec_permitted,
- cred->cap_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 = cred->uid;
- bprm->e_gid = cred->gid;
+ 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,
- cred->cap_permitted);
+ new->cap_permitted);
}
}
}
- cred->suid = cred->euid = cred->fsuid = bprm->e_uid;
- cred->sgid = cred->egid = cred->fsgid = bprm->e_gid;
+ new->suid = new->euid = new->fsuid = bprm->e_uid;
+ new->sgid = new->egid = new->fsgid = bprm->e_gid;
/* For init, we want to retain the capabilities set
* in the init_task struct. Thus we skip the usual
* capability rules */
if (!is_global_init(current)) {
- cred->cap_permitted = bprm->cap_post_exec_permitted;
+ new->cap_permitted = bprm->cap_post_exec_permitted;
if (bprm->cap_effective)
- cred->cap_effective = bprm->cap_post_exec_permitted;
+ new->cap_effective = bprm->cap_post_exec_permitted;
else
- cap_clear(cred->cap_effective);
+ cap_clear(new->cap_effective);
}
/*
@@ -431,15 +423,15 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
* Number 1 above might fail if you don't have a full bset, but I think
* that is interesting information to audit.
*/
- if (!cap_isclear(cred->cap_effective)) {
- if (!cap_issubset(CAP_FULL_SET, cred->cap_effective) ||
- (bprm->e_uid != 0) || (cred->uid != 0) ||
+ 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, &cred->cap_permitted,
- &cred->cap_effective);
+ audit_log_bprm_fcaps(bprm, new, old);
}
- cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+ new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+ return commit_creds(new);
}
int cap_bprm_secureexec (struct linux_binprm *bprm)
@@ -514,65 +506,49 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
* files..
* Thanks to Olaf Kirch and Peter Benie for spotting this.
*/
-static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
- int old_suid)
+static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
{
- struct cred *cred = current->cred;
-
- if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
- (cred->uid != 0 && cred->euid != 0 && cred->suid != 0) &&
+ if ((old->uid == 0 || old->euid == 0 || old->suid == 0) &&
+ (new->uid != 0 && new->euid != 0 && new->suid != 0) &&
!issecure(SECURE_KEEP_CAPS)) {
- cap_clear(cred->cap_permitted);
- cap_clear(cred->cap_effective);
- }
- if (old_euid == 0 && cred->euid != 0) {
- cap_clear(cred->cap_effective);
- }
- if (old_euid != 0 && cred->euid == 0) {
- cred->cap_effective = cred->cap_permitted;
+ cap_clear(new->cap_permitted);
+ cap_clear(new->cap_effective);
}
+ if (old->euid == 0 && new->euid != 0)
+ cap_clear(new->cap_effective);
+ if (old->euid != 0 && new->euid == 0)
+ new->cap_effective = new->cap_permitted;
}
-int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
- int flags)
+int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
{
- struct cred *cred = current->cred;
-
switch (flags) {
case LSM_SETID_RE:
case LSM_SETID_ID:
case LSM_SETID_RES:
/* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
- if (!issecure (SECURE_NO_SETUID_FIXUP)) {
- cap_emulate_setxuid (old_ruid, old_euid, old_suid);
- }
+ if (!issecure(SECURE_NO_SETUID_FIXUP))
+ cap_emulate_setxuid(new, old);
break;
case LSM_SETID_FS:
- {
- uid_t old_fsuid = old_ruid;
-
- /* Copied from kernel/sys.c:setfsuid. */
+ /* Copied from kernel/sys.c:setfsuid. */
- /*
- * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
- * if not, we might be a bit too harsh here.
- */
-
- if (!issecure (SECURE_NO_SETUID_FIXUP)) {
- if (old_fsuid == 0 && cred->fsuid != 0) {
- cred->cap_effective =
- cap_drop_fs_set(
- cred->cap_effective);
- }
- if (old_fsuid != 0 && cred->fsuid == 0) {
- cred->cap_effective =
- cap_raise_fs_set(
- cred->cap_effective,
- cred->cap_permitted);
- }
+ /*
+ * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
+ * if not, we might be a bit too harsh here.
+ */
+ if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+ if (old->fsuid == 0 && new->fsuid != 0) {
+ new->cap_effective =
+ cap_drop_fs_set(new->cap_effective);
+ }
+ if (old->fsuid != 0 && new->fsuid == 0) {
+ new->cap_effective =
+ cap_raise_fs_set(new->cap_effective,
+ new->cap_permitted);
}
- break;
}
+ break;
default:
return -EINVAL;
}
@@ -628,13 +604,14 @@ int cap_task_setnice (struct task_struct *p, int nice)
* this task could get inconsistent info. There can be no
* racing writer bc a task can only change its own caps.
*/
-static long cap_prctl_drop(unsigned long cap)
+static long cap_prctl_drop(struct cred *new, unsigned long cap)
{
if (!capable(CAP_SETPCAP))
return -EPERM;
if (!cap_valid(cap))
return -EINVAL;
- cap_lower(current->cred->cap_bset, cap);
+
+ cap_lower(new->cap_bset, cap);
return 0;
}
@@ -655,22 +632,29 @@ int cap_task_setnice (struct task_struct *p, int nice)
#endif
int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
- unsigned long arg4, unsigned long arg5, long *rc_p)
+ unsigned long arg4, unsigned long arg5)
{
- struct cred *cred = current_cred();
+ struct cred *new;
long error = 0;
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
switch (option) {
case PR_CAPBSET_READ:
+ error = -EINVAL;
if (!cap_valid(arg2))
- error = -EINVAL;
- else
- error = !!cap_raised(cred->cap_bset, arg2);
- break;
+ goto error;
+ error = !!cap_raised(new->cap_bset, arg2);
+ goto no_change;
+
#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
case PR_CAPBSET_DROP:
- error = cap_prctl_drop(arg2);
- break;
+ error = cap_prctl_drop(new, arg2);
+ if (error < 0)
+ goto error;
+ goto changed;
/*
* The next four prctl's remain to assist with transitioning a
@@ -692,12 +676,12 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
* capability-based-privilege environment.
*/
case PR_SET_SECUREBITS:
- if ((((cred->securebits & SECURE_ALL_LOCKS) >> 1)
- & (cred->securebits ^ arg2)) /*[1]*/
- || ((cred->securebits & SECURE_ALL_LOCKS
- & ~arg2)) /*[2]*/
- || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
- || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0)) { /*[4]*/
+ error = -EPERM;
+ if ((((new->securebits & SECURE_ALL_LOCKS) >> 1)
+ & (new->securebits ^ arg2)) /*[1]*/
+ || ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
+ || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
+ || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0) /*[4]*/
/*
* [1] no changing of bits that are locked
* [2] no unlocking of locks
@@ -705,50 +689,51 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
* [4] doing anything requires privilege (go read about
* the "sendmail capabilities bug")
*/
- error = -EPERM; /* cannot change a locked bit */
- } else {
- cred->securebits = arg2;
- }
- break;
+ )
+ /* cannot change a locked bit */
+ goto error;
+ new->securebits = arg2;
+ goto changed;
+
case PR_GET_SECUREBITS:
- error = cred->securebits;
- break;
+ error = new->securebits;
+ goto no_change;
#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
case PR_GET_KEEPCAPS:
if (issecure(SECURE_KEEP_CAPS))
error = 1;
- break;
+ goto no_change;
+
case PR_SET_KEEPCAPS:
+ error = -EINVAL;
if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
- error = -EINVAL;
- else if (issecure(SECURE_KEEP_CAPS_LOCKED))
- error = -EPERM;
- else if (arg2)
- cred->securebits |= issecure_mask(SECURE_KEEP_CAPS);
+ goto error;
+ error = -EPERM;
+ if (issecure(SECURE_KEEP_CAPS_LOCKED))
+ goto error;
+ if (arg2)
+ new->securebits |= issecure_mask(SECURE_KEEP_CAPS);
else
- cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
- break;
+ new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
+ goto changed;
default:
/* No functionality available - continue with default */
- return 0;
+ error = -ENOSYS;
+ goto error;
}
/* Functionality provided */
- *rc_p = error;
- return 1;
-}
-
-void cap_task_reparent_to_init (struct task_struct *p)
-{
- struct cred *cred = p->cred;
-
- cap_set_init_eff(cred->cap_effective);
- cap_clear(cred->cap_inheritable);
- cap_set_full(cred->cap_permitted);
- p->cred->securebits = SECUREBITS_DEFAULT;
+changed:
+ return commit_creds(new);
+
+no_change:
+ error = 0;
+error:
+ abort_creds(new);
+ return error;
}
int cap_syslog (int type)