seccomp: fix UAF in user-trap code

On the failure path, we do an fput() of the listener fd if the filter fails
to install (e.g. because of a TSYNC race that's lost, or if the thread is
killed, etc.). fput() doesn't actually release the fd, it just ads it to a
work queue. Then the thread proceeds to free the filter, even though the
listener struct file has a reference to it.

To fix this, on the failure path let's set the private data to null, so we
know in ->release() to ignore the filter.

Reported-by: [email protected]
Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")
Signed-off-by: Tycho Andersen <[email protected]>
Acked-by: Kees Cook <[email protected]>
Signed-off-by: James Morris <[email protected]>

0 files changed, 0 insertions, 0 deletions