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-rw-r--r--security/commoncap.c61
1 files changed, 36 insertions, 25 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index f80d11609391..e771cb1b2d79 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -77,12 +77,12 @@ int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
int cap, int audit)
{
for (;;) {
- /* The creator of the user namespace has all caps. */
- if (targ_ns != &init_user_ns && targ_ns->creator == cred->user)
+ /* The owner of the user namespace has all caps. */
+ if (targ_ns != &init_user_ns && uid_eq(targ_ns->owner, cred->euid))
return 0;
/* Do we have the necessary capabilities? */
- if (targ_ns == cred->user->user_ns)
+ if (targ_ns == cred->user_ns)
return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
/* Have we tried all of the parent namespaces? */
@@ -93,7 +93,7 @@ int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
*If you have a capability in a parent user ns, then you have
* it over all children user namespaces as well.
*/
- targ_ns = targ_ns->creator->user_ns;
+ targ_ns = targ_ns->parent;
}
/* We never get here */
@@ -137,10 +137,10 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
rcu_read_lock();
cred = current_cred();
child_cred = __task_cred(child);
- if (cred->user->user_ns == child_cred->user->user_ns &&
+ if (cred->user_ns == child_cred->user_ns &&
cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
goto out;
- if (ns_capable(child_cred->user->user_ns, CAP_SYS_PTRACE))
+ if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE))
goto out;
ret = -EPERM;
out:
@@ -169,10 +169,10 @@ int cap_ptrace_traceme(struct task_struct *parent)
rcu_read_lock();
cred = __task_cred(parent);
child_cred = current_cred();
- if (cred->user->user_ns == child_cred->user->user_ns &&
+ if (cred->user_ns == child_cred->user_ns &&
cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
goto out;
- if (has_ns_capability(parent, child_cred->user->user_ns, CAP_SYS_PTRACE))
+ if (has_ns_capability(parent, child_cred->user_ns, CAP_SYS_PTRACE))
goto out;
ret = -EPERM;
out:
@@ -215,7 +215,7 @@ static inline int cap_inh_is_capped(void)
/* they are so limited unless the current task has the CAP_SETPCAP
* capability
*/
- if (cap_capable(current_cred(), current_cred()->user->user_ns,
+ if (cap_capable(current_cred(), current_cred()->user_ns,
CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
return 0;
return 1;
@@ -473,19 +473,22 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
struct cred *new = bprm->cred;
bool effective, has_cap = false;
int ret;
+ kuid_t root_uid;
effective = false;
ret = get_file_caps(bprm, &effective, &has_cap);
if (ret < 0)
return ret;
+ root_uid = make_kuid(new->user_ns, 0);
+
if (!issecure(SECURE_NOROOT)) {
/*
* If the legacy file capability is set, then don't set privs
* for a setuid root binary run by a non-root user. Do set it
* for a root user just to cause least surprise to an admin.
*/
- if (has_cap && new->uid != 0 && new->euid == 0) {
+ if (has_cap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) {
warn_setuid_and_fcaps_mixed(bprm->filename);
goto skip;
}
@@ -496,12 +499,12 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
*
* If only the real uid is 0, we do not set the effective bit.
*/
- if (new->euid == 0 || new->uid == 0) {
+ if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) {
/* pP' = (cap_bset & ~0) | (pI & ~0) */
new->cap_permitted = cap_combine(old->cap_bset,
old->cap_inheritable);
}
- if (new->euid == 0)
+ if (uid_eq(new->euid, root_uid))
effective = true;
}
skip:
@@ -516,8 +519,8 @@ skip:
*
* In addition, if NO_NEW_PRIVS, then ensure we get no new privs.
*/
- if ((new->euid != old->uid ||
- new->egid != old->gid ||
+ if ((!uid_eq(new->euid, old->uid) ||
+ !gid_eq(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 */
@@ -553,7 +556,7 @@ skip:
*/
if (!cap_isclear(new->cap_effective)) {
if (!cap_issubset(CAP_FULL_SET, new->cap_effective) ||
- new->euid != 0 || new->uid != 0 ||
+ !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) ||
issecure(SECURE_NOROOT)) {
ret = audit_log_bprm_fcaps(bprm, new, old);
if (ret < 0)
@@ -578,16 +581,17 @@ skip:
int cap_bprm_secureexec(struct linux_binprm *bprm)
{
const struct cred *cred = current_cred();
+ kuid_t root_uid = make_kuid(cred->user_ns, 0);
- if (cred->uid != 0) {
+ if (!uid_eq(cred->uid, root_uid)) {
if (bprm->cap_effective)
return 1;
if (!cap_isclear(cred->cap_permitted))
return 1;
}
- return (cred->euid != cred->uid ||
- cred->egid != cred->gid);
+ return (!uid_eq(cred->euid, cred->uid) ||
+ !gid_eq(cred->egid, cred->gid));
}
/**
@@ -677,15 +681,21 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
*/
static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
{
- if ((old->uid == 0 || old->euid == 0 || old->suid == 0) &&
- (new->uid != 0 && new->euid != 0 && new->suid != 0) &&
+ kuid_t root_uid = make_kuid(old->user_ns, 0);
+
+ if ((uid_eq(old->uid, root_uid) ||
+ uid_eq(old->euid, root_uid) ||
+ uid_eq(old->suid, root_uid)) &&
+ (!uid_eq(new->uid, root_uid) &&
+ !uid_eq(new->euid, root_uid) &&
+ !uid_eq(new->suid, root_uid)) &&
!issecure(SECURE_KEEP_CAPS)) {
cap_clear(new->cap_permitted);
cap_clear(new->cap_effective);
}
- if (old->euid == 0 && new->euid != 0)
+ if (uid_eq(old->euid, root_uid) && !uid_eq(new->euid, root_uid))
cap_clear(new->cap_effective);
- if (old->euid != 0 && new->euid == 0)
+ if (!uid_eq(old->euid, root_uid) && uid_eq(new->euid, root_uid))
new->cap_effective = new->cap_permitted;
}
@@ -718,11 +728,12 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
* if not, we might be a bit too harsh here.
*/
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
- if (old->fsuid == 0 && new->fsuid != 0)
+ kuid_t root_uid = make_kuid(old->user_ns, 0);
+ if (uid_eq(old->fsuid, root_uid) && !uid_eq(new->fsuid, root_uid))
new->cap_effective =
cap_drop_fs_set(new->cap_effective);
- if (old->fsuid != 0 && new->fsuid == 0)
+ if (!uid_eq(old->fsuid, root_uid) && uid_eq(new->fsuid, root_uid))
new->cap_effective =
cap_raise_fs_set(new->cap_effective,
new->cap_permitted);
@@ -875,7 +886,7 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
|| ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/
|| (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
|| (cap_capable(current_cred(),
- current_cred()->user->user_ns, CAP_SETPCAP,
+ current_cred()->user_ns, CAP_SETPCAP,
SECURITY_CAP_AUDIT) != 0) /*[4]*/
/*
* [1] no changing of bits that are locked
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.