[FFmpeg-devel,4/4] avcodec/jpeg2000dec: Check PLT data somewhat

Submitted by Michael Niedermayer on April 16, 2019, 2:48 p.m.

Details

Message ID 20190416144834.20300-4-michael@niedermayer.cc
State Accepted
Commit e627113329da7c7c21b00562515a1f11437716f3
Headers show

Commit Message

Michael Niedermayer April 16, 2019, 2:48 p.m.
Fixes: Timeout (21sec -> 0.6sec)
Fixes: 14134/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5768371078955008

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/jpeg2000dec.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Andreas Rheinhardt April 25, 2019, 4:34 p.m.
Michael Niedermayer:
> Fixes: Timeout (21sec -> 0.6sec)
> Fixes: 14134/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5768371078955008
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/jpeg2000dec.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> index 9198cf87cb..62b0b1f9b7 100644
> --- a/libavcodec/jpeg2000dec.c
> +++ b/libavcodec/jpeg2000dec.c
> @@ -832,15 +832,21 @@ static uint8_t get_tlm(Jpeg2000DecoderContext *s, int n)
>  static uint8_t get_plt(Jpeg2000DecoderContext *s, int n)
>  {
>      int i;
> +    int v;
>  
>      av_log(s->avctx, AV_LOG_DEBUG,
>              "PLT marker at pos 0x%X\n", bytestream2_tell(&s->g) - 4);
>  
> +    if (n < 4)
> +        return AVERROR_INVALIDDATA;
> +
>      /*Zplt =*/ bytestream2_get_byte(&s->g);
>  
>      for (i = 0; i < n - 3; i++) {
> -        bytestream2_get_byte(&s->g);
> +        v = bytestream2_get_byte(&s->g);
>      }
> +    if (v & 0x80)
> +        return AVERROR_INVALIDDATA;
>  
>      return 0;
>  }
> 
get_tlm should probably return int as uint8_t can't hold the
AVERROR_INVALIDDATA. gcc gives Woverflow warnings because of that.

Currently, the return value of get_tlm is always >= 0 and so is the
return value of jpeg2000_read_main_headers and of
jpeg2000_decode_frame if one runs into the AVERROR_INVALIDDATA checks.
(I didn't test it, just took a quick glimpse at the code.)

- Andreas
Andreas Rheinhardt April 25, 2019, 4:44 p.m.
Andreas Rheinhardt:
> Michael Niedermayer:
>> Fixes: Timeout (21sec -> 0.6sec)
>> Fixes: 14134/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5768371078955008
>>
>> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
>> ---
>>  libavcodec/jpeg2000dec.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
>> index 9198cf87cb..62b0b1f9b7 100644
>> --- a/libavcodec/jpeg2000dec.c
>> +++ b/libavcodec/jpeg2000dec.c
>> @@ -832,15 +832,21 @@ static uint8_t get_tlm(Jpeg2000DecoderContext *s, int n)
>>  static uint8_t get_plt(Jpeg2000DecoderContext *s, int n)
>>  {
>>      int i;
>> +    int v;
>>  
>>      av_log(s->avctx, AV_LOG_DEBUG,
>>              "PLT marker at pos 0x%X\n", bytestream2_tell(&s->g) - 4);
>>  
>> +    if (n < 4)
>> +        return AVERROR_INVALIDDATA;
>> +
>>      /*Zplt =*/ bytestream2_get_byte(&s->g);
>>  
>>      for (i = 0; i < n - 3; i++) {
>> -        bytestream2_get_byte(&s->g);
>> +        v = bytestream2_get_byte(&s->g);
>>      }
>> +    if (v & 0x80)
>> +        return AVERROR_INVALIDDATA;
>>  
>>      return 0;
>>  }
>>
> get_tlm should probably return int as uint8_t can't hold the
> AVERROR_INVALIDDATA. gcc gives Woverflow warnings because of that.
> 
> Currently, the return value of get_tlm is always >= 0 and so is the
> return value of jpeg2000_read_main_headers and of
> jpeg2000_decode_frame if one runs into the AVERROR_INVALIDDATA checks.
> (I didn't test it, just took a quick glimpse at the code.)
> 
> - Andreas
> 
get_plt, not get_tlm. Sorry.

- Andreas
Michael Niedermayer April 25, 2019, 5:01 p.m.
On Thu, Apr 25, 2019 at 04:34:00PM +0000, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Fixes: Timeout (21sec -> 0.6sec)
> > Fixes: 14134/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5768371078955008
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavcodec/jpeg2000dec.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
> > index 9198cf87cb..62b0b1f9b7 100644
> > --- a/libavcodec/jpeg2000dec.c
> > +++ b/libavcodec/jpeg2000dec.c
> > @@ -832,15 +832,21 @@ static uint8_t get_tlm(Jpeg2000DecoderContext *s, int n)
> >  static uint8_t get_plt(Jpeg2000DecoderContext *s, int n)
> >  {
> >      int i;
> > +    int v;
> >  
> >      av_log(s->avctx, AV_LOG_DEBUG,
> >              "PLT marker at pos 0x%X\n", bytestream2_tell(&s->g) - 4);
> >  
> > +    if (n < 4)
> > +        return AVERROR_INVALIDDATA;
> > +
> >      /*Zplt =*/ bytestream2_get_byte(&s->g);
> >  
> >      for (i = 0; i < n - 3; i++) {
> > -        bytestream2_get_byte(&s->g);
> > +        v = bytestream2_get_byte(&s->g);
> >      }
> > +    if (v & 0x80)
> > +        return AVERROR_INVALIDDATA;
> >  
> >      return 0;
> >  }
> > 
> get_tlm should probably return int as uint8_t can't hold the
> AVERROR_INVALIDDATA. gcc gives Woverflow warnings because of that.
> 
> Currently, the return value of get_tlm is always >= 0 and so is the
> return value of jpeg2000_read_main_headers and of
> jpeg2000_decode_frame if one runs into the AVERROR_INVALIDDATA checks.
> (I didn't test it, just took a quick glimpse at the code.)

will fix

thanks

[...]

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diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 9198cf87cb..62b0b1f9b7 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -832,15 +832,21 @@  static uint8_t get_tlm(Jpeg2000DecoderContext *s, int n)
 static uint8_t get_plt(Jpeg2000DecoderContext *s, int n)
 {
     int i;
+    int v;
 
     av_log(s->avctx, AV_LOG_DEBUG,
             "PLT marker at pos 0x%X\n", bytestream2_tell(&s->g) - 4);
 
+    if (n < 4)
+        return AVERROR_INVALIDDATA;
+
     /*Zplt =*/ bytestream2_get_byte(&s->g);
 
     for (i = 0; i < n - 3; i++) {
-        bytestream2_get_byte(&s->g);
+        v = bytestream2_get_byte(&s->g);
     }
+    if (v & 0x80)
+        return AVERROR_INVALIDDATA;
 
     return 0;
 }