releases/3.0.49/sunrpc-prevent-kernel-stack-corruption-on-long-values-of-flush.patch

   1 From 212ba90696ab4884e2025b0b13726d67aadc2cd4 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <levinsasha928@gmail.com>
   3 Date: Tue, 17 Jul 2012 00:01:26 +0200
   4 Subject: SUNRPC: Prevent kernel stack corruption on long values of flush
   5
   6 From: Sasha Levin <levinsasha928@gmail.com>
   7
   8 commit 212ba90696ab4884e2025b0b13726d67aadc2cd4 upstream.
   9
  10 The buffer size in read_flush() is too small for the longest possible values
  11 for it. This can lead to a kernel stack corruption:
  12
  13 [   43.047329] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff833e64b4
  14 [   43.047329]
  15 [   43.049030] Pid: 6015, comm: trinity-child18 Tainted: G        W    3.5.0-rc7-next-20120716-sasha #221
  16 [   43.050038] Call Trace:
  17 [   43.050435]  [<ffffffff836c60c2>] panic+0xcd/0x1f4
  18 [   43.050931]  [<ffffffff833e64b4>] ? read_flush.isra.7+0xe4/0x100
  19 [   43.051602]  [<ffffffff810e94e6>] __stack_chk_fail+0x16/0x20
  20 [   43.052206]  [<ffffffff833e64b4>] read_flush.isra.7+0xe4/0x100
  21 [   43.052951]  [<ffffffff833e6500>] ? read_flush_pipefs+0x30/0x30
  22 [   43.053594]  [<ffffffff833e652c>] read_flush_procfs+0x2c/0x30
  23 [   43.053596]  [<ffffffff812b9a8c>] proc_reg_read+0x9c/0xd0
  24 [   43.053596]  [<ffffffff812b99f0>] ? proc_reg_write+0xd0/0xd0
  25 [   43.053596]  [<ffffffff81250d5b>] do_loop_readv_writev+0x4b/0x90
  26 [   43.053596]  [<ffffffff81250fd6>] do_readv_writev+0xf6/0x1d0
  27 [   43.053596]  [<ffffffff812510ee>] vfs_readv+0x3e/0x60
  28 [   43.053596]  [<ffffffff812511b8>] sys_readv+0x48/0xb0
  29 [   43.053596]  [<ffffffff8378167d>] system_call_fastpath+0x1a/0x1f
  30
  31 Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
  32 Signed-off-by: J. Bruce Fields <bfields@redhat.com>
  33 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  34
  35 ---
  36  net/sunrpc/cache.c |    4 ++--
  37  1 file changed, 2 insertions(+), 2 deletions(-)
  38
  39 --- a/net/sunrpc/cache.c
  40 +++ b/net/sunrpc/cache.c
  41 @@ -1404,11 +1404,11 @@ static ssize_t read_flush(struct file *f
  42                           size_t count, loff_t *ppos,
  43                           struct cache_detail *cd)
  44  {
  45 -       char tbuf[20];
  46 +       char tbuf[22];
  47         unsigned long p = *ppos;
  48         size_t len;
  49
  50 -       sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
  51 +       snprintf(tbuf, sizeof(tbuf), "%lu\n", convert_to_wallclock(cd->flush_time));
  52         len = strlen(tbuf);
  53         if (p >= len)
  54                 return 0;