path: root/kernel
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authorOleg Nesterov <oleg@redhat.com>2013-08-06 19:38:55 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-08-06 13:13:24 -0700
commit6160968cee8b90a5dd95318d716e31d7775c4ef3 (patch)
tree3183e99bd38da761532685c045c2eac29c80b0b9 /kernel
parentLinux 3.11-rc4 (diff)
userns: unshare_userns(&cred) should not populate cred on failure
unshare_userns(new_cred) does *new_cred = prepare_creds() before create_user_ns() which can fail. However, the caller expects that it doesn't need to take care of new_cred if unshare_userns() fails. We could change the single caller, sys_unshare(), but I think it would be more clean to avoid the side effects on failure, so with this patch unshare_userns() does put_cred() itself and initializes *new_cred only if create_user_ns() succeeeds. Cc: stable@vger.kernel.org Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index d8c30db06c5b..6e50a44610ee 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -105,16 +105,21 @@ int create_user_ns(struct cred *new)
int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
struct cred *cred;
+ int err = -ENOMEM;
if (!(unshare_flags & CLONE_NEWUSER))
return 0;
cred = prepare_creds();
- if (!cred)
- return -ENOMEM;
+ if (cred) {
+ err = create_user_ns(cred);
+ if (err)
+ put_cred(cred);
+ else
+ *new_cred = cred;
+ }
- *new_cred = cred;
- return create_user_ns(cred);
+ return err;
void free_user_ns(struct user_namespace *ns)