Messages in this thread Patch in this message | | | Date | Thu, 7 Jan 2016 10:31:32 -0500 | From | Benjamin LaHaise <> | Subject | Re: int overflow in io_getevents |
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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); }
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