tracing: t_start: reset FTRACE_ITER_HASH in case of seek/pread

Be sure to avoid entering t_show() with FTRACE_ITER_HASH set without
having properly started the iterator to iterate the hash.  This case is
degenerate and, as discovered by Robert Swiecki, can cause t_hash_show()
to misuse a pointer.  This causes a NULL ptr deref with possible security
implications.  Tracked as CVE-2010-3079.

Cc: Robert Swiecki <swiecki@google.com>
Cc: Eugene Teo <eugene@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Chris Wright 2010-09-09 16:34:59 -07:00 committed by Steven Rostedt
parent 5e11637e2c
commit df09162550

View File

@ -1510,6 +1510,8 @@ static void *t_start(struct seq_file *m, loff_t *pos)
if (*pos > 0)
return t_hash_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
/* reset in case of seek/pread */
iter->flags &= ~FTRACE_ITER_HASH;
return iter;
}