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authorOleg Nesterov <oleg@redhat.com>2012-04-09 21:03:50 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-11 08:20:11 -0700
commit79549c6dfda0603dba9a70a53467ce62d9335c33 (patch)
tree88de05761354d81916b6a929ae9ef2fa1b51e3e5 /kernel/cred.c
parent923e9a1399b620d063cd88537c64561bc3d5f905 (diff)
downloadlinux-79549c6dfda0603dba9a70a53467ce62d9335c33.tar.gz
cred: copy_process() should clear child->replacement_session_keyring
keyctl_session_to_parent(task) sets ->replacement_session_keyring, it should be processed and cleared by key_replace_session_keyring(). However, this task can fork before it notices TIF_NOTIFY_RESUME and the new child gets the bogus ->replacement_session_keyring copied by dup_task_struct(). This is obviously wrong and, if nothing else, this leads to put_cred(already_freed_cred). change copy_creds() to clear this member. If copy_process() fails before this point the wrong ->replacement_session_keyring doesn't matter, exit_creds() won't be called. Cc: <stable@vger.kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cred.c')
-rw-r--r--kernel/cred.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 97b36eeca4c..e70683d9ec3 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -386,6 +386,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
struct cred *new;
int ret;
+ p->replacement_session_keyring = NULL;
+
if (
#ifdef CONFIG_KEYS
!p->cred->thread_keyring &&