[PATCH][GIT PULL][v2.6.36] tracing: t_start: reset FTRACE_ITER_HASH in case of seek/pread

[Steven Rostedt]

Ingo,

The previous fixed only fixed lseek, Chris's fix also handles pread().

Please pull the latest tip/perf/urgent tree, which can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/perf/urgent

Chris Wright (1):
tracing: t_start: reset FTRACE_ITER_HASH in case of seek/pread

----
kernel/trace/ftrace.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
---------------------------
commit df09162550fbb53354f0c88e85b5d0e6129ee9cc
Author: Chris Wright <chr...@sous-sol.org>
Date: Thu Sep 9 16:34:59 2010 -0700

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 <swi...@google.com>
Cc: Eugene Teo <eug...@redhat.com>
Cc: <sta...@kernel.org>
Signed-off-by: Chris Wright <chr...@sous-sol.org>
Signed-off-by: Steven Rostedt <ros...@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 83a16e9..fa7ece6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -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;
}

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[Ingo Molnar]

* Steven Rostedt <ros...@goodmis.org> wrote:

>
> Ingo,
>
> The previous fixed only fixed lseek, Chris's fix also handles pread().
>
> Please pull the latest tip/perf/urgent tree, which can be found at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/perf/urgent
>
>
> Chris Wright (1):
> tracing: t_start: reset FTRACE_ITER_HASH in case of seek/pread
>
> ----
> kernel/trace/ftrace.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)

Pulled, thanks Steve!

Ingo