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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-18 10:55:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-18 10:55:28 -0800
commita2faf2fc534f57ba26bc4d613795236ed4f5fb1c (patch)
treed75c4daadb469c8f08c498532fbf1fff68879e69 /security
parent4351654e3ddf86a04966163dce4def586303e5cc (diff)
parent5155040ed349950e16c093ba8e65ad534994df2a (diff)
downloadlinux-a2faf2fc534f57ba26bc4d613795236ed4f5fb1c.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull (again) user namespace infrastructure changes from Eric Biederman: "Those bugs, those darn embarrasing bugs just want don't want to get fixed. Linus I just updated my mirror of your kernel.org tree and it appears you successfully pulled everything except the last 4 commits that fix those embarrasing bugs. When you get a chance can you please repull my branch" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Fix typo in description of the limitation of userns_install userns: Add a more complete capability subset test to commit_creds userns: Require CAP_SYS_ADMIN for most uses of setns. Fix cap_capable to only allow owners in the parent user namespace to have caps.
Diffstat (limited to 'security')
-rw-r--r--security/commoncap.c25
1 files changed, 17 insertions, 8 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index 6dbae4650ab..7ee08c756d6 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -76,24 +76,33 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
int cap, int audit)
{
- for (;;) {
- /* The owner of the user namespace has all caps. */
- if (targ_ns != &init_user_ns && uid_eq(targ_ns->owner, cred->euid))
- return 0;
+ struct user_namespace *ns = targ_ns;
+ /* See if cred has the capability in the target user namespace
+ * by examining the target user namespace and all of the target
+ * user namespace's parents.
+ */
+ for (;;) {
/* Do we have the necessary capabilities? */
- if (targ_ns == cred->user_ns)
+ if (ns == cred->user_ns)
return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
/* Have we tried all of the parent namespaces? */
- if (targ_ns == &init_user_ns)
+ if (ns == &init_user_ns)
return -EPERM;
+ /*
+ * The owner of the user namespace in the parent of the
+ * user namespace has all caps.
+ */
+ if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid))
+ return 0;
+
/*
- *If you have a capability in a parent user ns, then you have
+ * 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->parent;
+ ns = ns->parent;
}
/* We never get here */