2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Oleg Nesterov <o...@redhat.com>
commit 79549c6dfda0603dba9a70a53467ce62d9335c33 upstream
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: <sta...@vger.kernel.org>
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: David Howells <dhowe...@redhat.com>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Willy Tarreau <w...@1wt.eu>
---
kernel/cred.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/kernel/cred.c b/kernel/cred.c
index 0b5b5fc..9c06d10 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -443,6 +443,8 @@ int copy_creds(struct task_struct *p, unsigned long
clone_flags)
mutex_init(&p->cred_guard_mutex);
+ p->replacement_session_keyring = NULL;
+
if (
#ifdef CONFIG_KEYS
!p->cred->thread_keyring &&
--
1.7.2.1.45.g54fbc
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