2010-11-18 22:10:59

by dann frazier

Subject: [PATCH] [OCFS2] ocfs2_connection_find() returns pointer to bad structure

If ocfs2_live_connection_list is empty, ocfs2_connection_find() will return
a pointer to the LIST_HEAD, cast as a ocfs2_live_connection. This can cause
an oops when ocfs2_control_send_down() dereferences c->oc_conn:

Call Trace:
[<ffffffffa00c2a3c>] ocfs2_control_message+0x28c/0x2b0 [ocfs2_stack_user]
[<ffffffffa00c2a95>] ocfs2_control_write+0x35/0xb0 [ocfs2_stack_user]
[<ffffffff81143a88>] vfs_write+0xb8/0x1a0
[<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[<ffffffff811442f1>] sys_write+0x51/0x80
[<ffffffff810121b2>] system_call_fastpath+0x16/0x1b

Fix by explicitly returning NULL if no match is found.

Signed-off-by: dann frazier <[email protected]>
---
fs/ocfs2/stack_user.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index 252e7c8..a5ebe42 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -190,7 +190,7 @@ static struct ocfs2_live_connection *ocfs2_connection_find(const char *name)
return c;
}

- return c;
+ return NULL;
}

/*
--
1.7.2.3

2010-11-18 23:45:49

by Joel Becker

Subject: Re: [Ocfs2-devel] [PATCH] [OCFS2] ocfs2_connection_find() returns pointer to bad structure

On Thu, Nov 18, 2010 at 03:03:09PM -0700, dann frazier wrote:
> If ocfs2_live_connection_list is empty, ocfs2_connection_find() will return
> a pointer to the LIST_HEAD, cast as a ocfs2_live_connection. This can cause
> an oops when ocfs2_control_send_down() dereferences c->oc_conn:
>
> Call Trace:
> [<ffffffffa00c2a3c>] ocfs2_control_message+0x28c/0x2b0 [ocfs2_stack_user]
> [<ffffffffa00c2a95>] ocfs2_control_write+0x35/0xb0 [ocfs2_stack_user]
> [<ffffffff81143a88>] vfs_write+0xb8/0x1a0
> [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
> [<ffffffff811442f1>] sys_write+0x51/0x80
> [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
>
> Fix by explicitly returning NULL if no match is found.
>
> Signed-off-by: dann frazier <[email protected]>

This patch is now in the fixes branch of ocfs2.git.

Joel

--

"I don't even butter my bread; I consider that cooking."
- Katherine Cebrian

Joel Becker
Senior Development Manager
Oracle
E-mail: [email protected]
Phone: (650) 506-8127