diff mbox

[FFmpeg-devel] aiffdec: fix division by zero

Message ID 9be862e6-95d4-d779-b47b-bb0c777ae0ab@googlemail.com
State Accepted
Headers show

Commit Message

Andreas Cadhalpun Oct. 20, 2016, 6:11 p.m. UTC
On 20.10.2016 02:56, Michael Niedermayer wrote:
> On Wed, Oct 19, 2016 at 09:18:51PM +0200, Andreas Cadhalpun wrote:
>> This is similar to commit c143a9c.
>>
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
>> ---
>>  libavformat/aiffdec.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> can aiff work without block_align ?

Well, it can use a fall-back value. That value can be wrong, of course.

> either way, block_duration is from the header reading
> if its still accurate then using it together with 1 instead of the
> matching block align is quite likely not correct
> OTOH if block_duration does not represent the actual content then
> the duration would only be correct by pure chance
> 
> Its a bit unfortunate that theres no usecase with an undamaged sample
> which would have clear correct values
> 
> one has to work on the assumptation of a use case where the user needs
> to override the codec and then ask "what is correct to do" that makes
> this a bit tricky ...

Alternatively aiff_read_packet could just error out, if you prefer that.
Patch doing that attached.

Best regards,
Andreas

Comments

Michael Niedermayer Oct. 20, 2016, 11:32 p.m. UTC | #1
On Thu, Oct 20, 2016 at 08:11:19PM +0200, Andreas Cadhalpun wrote:
> On 20.10.2016 02:56, Michael Niedermayer wrote:
> > On Wed, Oct 19, 2016 at 09:18:51PM +0200, Andreas Cadhalpun wrote:
> >> This is similar to commit c143a9c.
> >>
> >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
> >> ---
> >>  libavformat/aiffdec.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > can aiff work without block_align ?
> 
> Well, it can use a fall-back value. That value can be wrong, of course.
> 
> > either way, block_duration is from the header reading
> > if its still accurate then using it together with 1 instead of the
> > matching block align is quite likely not correct
> > OTOH if block_duration does not represent the actual content then
> > the duration would only be correct by pure chance
> > 
> > Its a bit unfortunate that theres no usecase with an undamaged sample
> > which would have clear correct values
> > 
> > one has to work on the assumptation of a use case where the user needs
> > to override the codec and then ask "what is correct to do" that makes
> > this a bit tricky ...
> 
> Alternatively aiff_read_packet could just error out, if you prefer that.
> Patch doing that attached.
> 
> Best regards,
> Andreas
> 

>  aiffdec.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 2fb78e5573b52b635b5077a265a54542e054cf02  0001-aiff-check-block_align-in-aiff_read_packet.patch
> From d1edb842a886de0bae6e32ac602f2fef6810081a Mon Sep 17 00:00:00 2001
> From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
> Date: Thu, 20 Oct 2016 20:08:15 +0200
> Subject: [PATCH] aiff: check block_align in aiff_read_packet
> 
> It can be unset in avcodec_parameters_from_context and a value of 0
> causes SIGFPE crashes.

LGTM

thx

[...]
Andreas Cadhalpun Oct. 21, 2016, 5:43 p.m. UTC | #2
On 21.10.2016 01:32, Michael Niedermayer wrote:
> On Thu, Oct 20, 2016 at 08:11:19PM +0200, Andreas Cadhalpun wrote:
>>  aiffdec.c |    5 +++++
>>  1 file changed, 5 insertions(+)
>> 2fb78e5573b52b635b5077a265a54542e054cf02  0001-aiff-check-block_align-in-aiff_read_packet.patch
>> From d1edb842a886de0bae6e32ac602f2fef6810081a Mon Sep 17 00:00:00 2001
>> From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
>> Date: Thu, 20 Oct 2016 20:08:15 +0200
>> Subject: [PATCH] aiff: check block_align in aiff_read_packet
>>
>> It can be unset in avcodec_parameters_from_context and a value of 0
>> causes SIGFPE crashes.
> 
> LGTM

Pushed.

Best regards,
Andreas
diff mbox

Patch

From d1edb842a886de0bae6e32ac602f2fef6810081a Mon Sep 17 00:00:00 2001
From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Date: Thu, 20 Oct 2016 20:08:15 +0200
Subject: [PATCH] aiff: check block_align in aiff_read_packet

It can be unset in avcodec_parameters_from_context and a value of 0
causes SIGFPE crashes.

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
---
 libavformat/aiffdec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavformat/aiffdec.c b/libavformat/aiffdec.c
index de82787..59e969d 100644
--- a/libavformat/aiffdec.c
+++ b/libavformat/aiffdec.c
@@ -371,6 +371,11 @@  static int aiff_read_packet(AVFormatContext *s,
     if (max_size <= 0)
         return AVERROR_EOF;
 
+    if (!st->codecpar->block_align) {
+        av_log(s, AV_LOG_ERROR, "block_align not set\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     /* Now for that packet */
     switch (st->codecpar->codec_id) {
     case AV_CODEC_ID_ADPCM_IMA_QT:
-- 
2.9.3