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| author | Oleg Nesterov <oleg@redhat.com> | 2012-04-09 21:03:50 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-13 08:14:08 -0700 |
| commit | a27f3e06be07cd3719f8c42092de3ebfc9202923 (patch) | |
| tree | fb90b498832a81490aedab782c6d7454b2fcecee | |
| parent | 49d06c03741d3329e568ba7d88cb32e700ef9156 (diff) | |
| download | lwn-a27f3e06be07cd3719f8c42092de3ebfc9202923.tar.gz lwn-a27f3e06be07cd3719f8c42092de3ebfc9202923.zip | |
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>
| -rw-r--r-- | kernel/cred.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 174fa84eca30..3a55ea4fa983 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 ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && |