[ 3.5.yuz extended stable ] Patch "SUNRPC: Prevent kernel stack corruption on long values of" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    SUNRPC: Prevent kernel stack corruption on long values of

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From 05b31fd6318a07f2bccac8b8be3b300543c0c255 Mon Sep 17 00:00:00 2001
From: Sasha Levin <levinsasha928 at gmail.com>
Date: Tue, 17 Jul 2012 00:01:26 +0200
Subject: [PATCH] SUNRPC: Prevent kernel stack corruption on long values of
 flush

commit 212ba90696ab4884e2025b0b13726d67aadc2cd4 upstream.

The buffer size in read_flush() is too small for the longest possible values
for it. This can lead to a kernel stack corruption:

[   43.047329] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff833e64b4
[   43.047329]
[   43.049030] Pid: 6015, comm: trinity-child18 Tainted: G        W    3.5.0-rc7-next-20120716-sasha #221
[   43.050038] Call Trace:
[   43.050435]  [<ffffffff836c60c2>] panic+0xcd/0x1f4
[   43.050931]  [<ffffffff833e64b4>] ? read_flush.isra.7+0xe4/0x100
[   43.051602]  [<ffffffff810e94e6>] __stack_chk_fail+0x16/0x20
[   43.052206]  [<ffffffff833e64b4>] read_flush.isra.7+0xe4/0x100
[   43.052951]  [<ffffffff833e6500>] ? read_flush_pipefs+0x30/0x30
[   43.053594]  [<ffffffff833e652c>] read_flush_procfs+0x2c/0x30
[   43.053596]  [<ffffffff812b9a8c>] proc_reg_read+0x9c/0xd0
[   43.053596]  [<ffffffff812b99f0>] ? proc_reg_write+0xd0/0xd0
[   43.053596]  [<ffffffff81250d5b>] do_loop_readv_writev+0x4b/0x90
[   43.053596]  [<ffffffff81250fd6>] do_readv_writev+0xf6/0x1d0
[   43.053596]  [<ffffffff812510ee>] vfs_readv+0x3e/0x60
[   43.053596]  [<ffffffff812511b8>] sys_readv+0x48/0xb0
[   43.053596]  [<ffffffff8378167d>] system_call_fastpath+0x1a/0x1f

Signed-off-by: Sasha Levin <levinsasha928 at gmail.com>
Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/sunrpc/cache.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 47ad266..97bbcdc 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1406,11 +1406,11 @@ static ssize_t read_flush(struct file *file, char __user *buf,
 			  size_t count, loff_t *ppos,
 			  struct cache_detail *cd)
 {
-	char tbuf[20];
+	char tbuf[22];
 	unsigned long p = *ppos;
 	size_t len;

-	sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
+	snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
 	len = strlen(tbuf);
 	if (p >= len)
 		return 0;
--
1.7.9.5