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| author | Oleg Nesterov <oleg@redhat.com> | 2012-04-09 21:03:50 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-04-11 08:20:11 -0700 |
| commit | 79549c6dfda0603dba9a70a53467ce62d9335c33 (patch) | |
| tree | 88de05761354d81916b6a929ae9ef2fa1b51e3e5 /kernel/cred.c | |
| parent | 923e9a1399b620d063cd88537c64561bc3d5f905 (diff) | |
| download | lwn-79549c6dfda0603dba9a70a53467ce62d9335c33.tar.gz lwn-79549c6dfda0603dba9a70a53467ce62d9335c33.zip | |
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.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 97b36eeca4c9..e70683d9ec32 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 && |