* [PATCH] bitmap: Fix undefined shift in __bitmap_shift_left()
@ 2014-10-22 12:43 Jan Kara
2014-10-22 12:48 ` Jan Kara
0 siblings, 1 reply; 2+ messages in thread
From: Jan Kara @ 2014-10-22 12:43 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Jan Kara, Rasmus Villemoes, stable
It __bitmap_shift_left() is asked to shift by a multiple of
BITS_PER_LONG, it will try to shift a long value by BITS_PER_LONG bits
which is undefined. Change the function to take this into account.
Coverity-id: 1192175
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
lib/bitmap.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index cd250a2e14cb..02a8a439fcc7 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -172,7 +172,9 @@ void __bitmap_shift_left(unsigned long *dst,
upper = src[k];
if (left && k == lim - 1)
upper &= (1UL << left) - 1;
- dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
+ dst[k + off] = upper << rem;
+ if (rem)
+ dst[k + off] |= lower >> (BITS_PER_LONG - rem);
if (left && k + off == lim - 1)
dst[k + off] &= (1UL << left) - 1;
}
--
1.8.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] bitmap: Fix undefined shift in __bitmap_shift_left()
2014-10-22 12:43 [PATCH] bitmap: Fix undefined shift in __bitmap_shift_left() Jan Kara
@ 2014-10-22 12:48 ` Jan Kara
0 siblings, 0 replies; 2+ messages in thread
From: Jan Kara @ 2014-10-22 12:48 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Jan Kara, Rasmus Villemoes, stable
On Wed 22-10-14 14:43:51, Jan Kara wrote:
> It __bitmap_shift_left() is asked to shift by a multiple of
> BITS_PER_LONG, it will try to shift a long value by BITS_PER_LONG bits
> which is undefined. Change the function to take this into account.
>
> Coverity-id: 1192175
> CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> CC: stable@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
Oops, there's one more occurence of this. I'll send an updated patch.
Honza
> ---
> lib/bitmap.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index cd250a2e14cb..02a8a439fcc7 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -172,7 +172,9 @@ void __bitmap_shift_left(unsigned long *dst,
> upper = src[k];
> if (left && k == lim - 1)
> upper &= (1UL << left) - 1;
> - dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
> + dst[k + off] = upper << rem;
> + if (rem)
> + dst[k + off] |= lower >> (BITS_PER_LONG - rem);
> if (left && k + off == lim - 1)
> dst[k + off] &= (1UL << left) - 1;
> }
> --
> 1.8.1.4
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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