lkml.org 
[lkml]   [2016]   [Jan]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: int overflow in io_getevents
On Thu, Jan 07, 2016 at 10:12:02AM +0100, Dmitry Vyukov wrote:
...
> Sorry, but the following program still prints -9223372036562067969. I
> think timespec_valid check will do.

Ah, right. Yes, using timespec_valid() instead of timespec_valid_strict()
as initially proposed will address my concerns. Updated commit below.

-ben
--
"Thought is the essence of where you are now."

commit 3a55c535cf3836257434518bd6bc11464c493492
Author: Benjamin LaHaise <bcrl@kvack.org>
Date: Thu Jan 7 10:25:44 2016 -0500

aio: handle integer overflow in io_getevents() timespec usage

Dmitry Vyukov reported an integer overflow in io_getevents() when
running a fuzzer. Upon investigation, the triggers appears to be that
an invalid value for the tv_sec or tv_nsec was passed in which is not
handled by timespec_to_ktime(). This patch fixes that by making
io_getevents() return -EINVAL when timespec_valid() checks fail. We
use timespec_valid() instead of timespec_valid_strict() to avoid issues
caused by userspace not knowing the cutoff for KTIME_SEC_MAX.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>

diff --git a/fs/aio.c b/fs/aio.c
index 155f842..d161a2f 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1269,6 +1269,8 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr,

if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
return -EFAULT;
+ if (!timespec_valid())
+ return -EINVAL;

until = timespec_to_ktime(ts);
}

\
 
 \ /
  Last update: 2016-01-07 17:01    [W:0.072 / U:0.516 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site