diff mbox

[FFmpeg-devel,V1,1/2] avutil/common: Fix underflow for ROUNDED_DIV with unsigned integer

Message ID 1570067596-19224-1-git-send-email-mypopydev@gmail.com
State Accepted
Commit 9f353e376b161eb16a78fd7ad727c9513ac60d13
Headers show

Commit Message

Jun Zhao Oct. 3, 2019, 1:53 a.m. UTC 
From: Mengye Lv <mengyelv@tencent.com>

When used ROUNDED_DIV(a,b), if a is unsigned integer zero, it's
will lead to an underflow issue(it called unsigned integer
wrapping).

Fixes #8062

Signed-off-by: Mengye Lv <mengyelv@tencent.com>
Signed-off-by: Jun Zhao <barryjzhao@tencent.com>
---
 libavutil/common.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Comments

Michael Niedermayer Oct. 5, 2019, 2:16 p.m. UTC | #1 
On Thu, Oct 03, 2019 at 09:53:15AM +0800, Jun Zhao wrote:
> From: Mengye Lv <mengyelv@tencent.com>
> 
> When used ROUNDED_DIV(a,b), if a is unsigned integer zero, it's
> will lead to an underflow issue(it called unsigned integer
> wrapping).
> 
> Fixes #8062
> 
> Signed-off-by: Mengye Lv <mengyelv@tencent.com>
> Signed-off-by: Jun Zhao <barryjzhao@tencent.com>
> ---
>  libavutil/common.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

LGTM

thx

[...]
Jun Zhao Oct. 8, 2019, 12:58 a.m. UTC | #2 
On Sat, Oct 5, 2019 at 10:16 PM Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> On Thu, Oct 03, 2019 at 09:53:15AM +0800, Jun Zhao wrote:
> > From: Mengye Lv <mengyelv@tencent.com>
> >
> > When used ROUNDED_DIV(a,b), if a is unsigned integer zero, it's
> > will lead to an underflow issue(it called unsigned integer
> > wrapping).
> >
> > Fixes #8062
> >
> > Signed-off-by: Mengye Lv <mengyelv@tencent.com>
> > Signed-off-by: Jun Zhao <barryjzhao@tencent.com>
> > ---
> >  libavutil/common.h |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
>
> LGTM
>
> thx
>
Applied, Thx
diff mbox

Patch

diff --git a/libavutil/common.h b/libavutil/common.h
index af35397..f09f0b4 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -53,7 +53,7 @@ 
 //rounded division & shift
 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
 /* assume b>0 */
-#define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
+#define ROUNDED_DIV(a,b) (((a)>=0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
 /* Fast a/(1<<b) rounded toward +inf. Assume a>=0 and b>=0 */
 #define AV_CEIL_RSHIFT(a,b) (!av_builtin_constant_p(b) ? -((-(a)) >> (b)) \
                                                        : ((a) + (1<<(b)) - 1) >> (b))