Messages in this thread Patch in this message | | | Date | Wed, 11 Apr 2012 16:13:46 -0700 | From | Greg KH <> | Subject | [ 39/42] cred: copy_process() should clear child->replacement_session_keyring |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Oleg Nesterov <oleg@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.
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>
--- kernel/cred.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/kernel/cred.c +++ b/kernel/cred.c @@ -385,6 +385,8 @@ int copy_creds(struct task_struct *p, un struct cred *new; int ret; + p->replacement_session_keyring = NULL; + if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring &&
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