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authorOleg Nesterov <oleg@redhat.com>2012-04-09 21:03:50 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-13 09:13:57 -0700
commitb502007fc61b7799148ccd1bc4a502acd1a0b8fa (patch)
parente4d3aa91a6b7d6a6ca73b6c169848f7acbecbd8f (diff)
cred: copy_process() should clear child->replacement_session_keyring
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. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 5791612a4045..48c6fd3bc848 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -385,6 +385,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
struct cred *new;
int ret;
+ p->replacement_session_keyring = NULL;
if (
!p->cred->thread_keyring &&