diff mbox series

[FFmpeg-devel,v2,1/2] avformat/mov: add validate_box_size

Message ID 20211222124728.7300-1-ffmpeg@gyani.pro
State New
Headers show
Series [FFmpeg-devel,v2,1/2] avformat/mov: add validate_box_size | expand

Checks

Context Check Description
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished
andriy/makex86 warning New warnings during build
andriy/make_ppc success Make finished
andriy/make_fate_ppc success Make fate finished
andriy/makeppc warning New warnings during build

Commit Message

Gyan Doshi Dec. 22, 2021, 12:47 p.m. UTC
Helper function to check if stored box size is correct and looks
to be fully available.
---
 libavformat/mov.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

Comments

Nicolas George Dec. 22, 2021, 1:13 p.m. UTC | #1
Gyan Doshi (12021-12-22):
> Helper function to check if stored box size is correct and looks
> to be fully available.
> ---
>  libavformat/mov.c | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 2aed6e80ef..7de95b7ab0 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -80,6 +80,40 @@ static int mov_read_mfra(MOVContext *c, AVIOContext *f);
>  static int64_t add_ctts_entry(MOVCtts** ctts_data, unsigned int* ctts_count, unsigned int* allocated_size,
>                                int count, int duration);
>  
> +/**  Check if the box size meets the requirements passed in limit and constraint_type.
> + *   If input avio_size is valid, it checks if box size appears to be available.
> + *
> + *   constraint_type may be
> + *   0  if the box size has to be exactly equal to limit
> + *  -1  if the box size has to be at most limit
> + *   1  if the box size has to be at least limit
> + *
> + *   Returns 0 if size meets requirements.
> + */
> +static int validate_box_size(MOVContext *c, MOVAtom atom, AVIOContext *pb,
> +                             int64_t pos, int64_t limit, int constraint_type)
> +{
> +    int size_fit;
> +    int64_t input_size = avio_size(pb);
> +
> +    if (input_size > 0 &&
> +        input_size - pos < atom.size) {
> +        av_log(c->fc, AV_LOG_ERROR, "Box %s is truncated\n", av_fourcc2str(atom.type));
> +        return AVERROR_INVALIDDATA;
> +    }
> +

> +    if (FFABS(constraint_type) > 1)
> +        return AVERROR_BUG;

av_assert() whould have been the right choice here.

> +
> +    switch(constraint_type) {
> +    case  0: size_fit = atom.size == limit; break;

> +    case -1: size_fit = atom.size <= limit; break;
> +    case  1: size_fit = atom.size >= limit; break;

This code is unused, AFAICS. Not a good idea.

> +    }
> +
> +   return !size_fit;
> +}
> +
>  static int mov_metadata_track_or_disc_number(MOVContext *c, AVIOContext *pb,
>                                               unsigned len, const char *key)
>  {

I think the changes belong in a single patch.

Regards,
Gyan Doshi Dec. 22, 2021, 1:33 p.m. UTC | #2
On 2021-12-22 06:43 pm, Nicolas George wrote:
> Gyan Doshi (12021-12-22):
>> Helper function to check if stored box size is correct and looks
>> to be fully available.
>> ---
>>   libavformat/mov.c | 34 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 34 insertions(+)
>>
>> diff --git a/libavformat/mov.c b/libavformat/mov.c
>> index 2aed6e80ef..7de95b7ab0 100644
>> --- a/libavformat/mov.c
>> +++ b/libavformat/mov.c
>> @@ -80,6 +80,40 @@ static int mov_read_mfra(MOVContext *c, AVIOContext *f);
>>   static int64_t add_ctts_entry(MOVCtts** ctts_data, unsigned int* ctts_count, unsigned int* allocated_size,
>>                                 int count, int duration);
>>   
>> +/**  Check if the box size meets the requirements passed in limit and constraint_type.
>> + *   If input avio_size is valid, it checks if box size appears to be available.
>> + *
>> + *   constraint_type may be
>> + *   0  if the box size has to be exactly equal to limit
>> + *  -1  if the box size has to be at most limit
>> + *   1  if the box size has to be at least limit
>> + *
>> + *   Returns 0 if size meets requirements.
>> + */
>> +static int validate_box_size(MOVContext *c, MOVAtom atom, AVIOContext *pb,
>> +                             int64_t pos, int64_t limit, int constraint_type)
>> +{
>> +    int size_fit;
>> +    int64_t input_size = avio_size(pb);
>> +
>> +    if (input_size > 0 &&
>> +        input_size - pos < atom.size) {
>> +        av_log(c->fc, AV_LOG_ERROR, "Box %s is truncated\n", av_fourcc2str(atom.type));
>> +        return AVERROR_INVALIDDATA;
>> +    }
>> +
>> +    if (FFABS(constraint_type) > 1)
>> +        return AVERROR_BUG;
> av_assert() whould have been the right choice here.

Will change.

>
>> +
>> +    switch(constraint_type) {
>> +    case  0: size_fit = atom.size == limit; break;
>> +    case -1: size_fit = atom.size <= limit; break;
>> +    case  1: size_fit = atom.size >= limit; break;
> This code is unused, AFAICS. Not a good idea.

I'll call this function in other box readers. Their requirements are 
different.
That's why I made the check a separate function.

Regards,
Gyan
diff mbox series

Patch

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 2aed6e80ef..7de95b7ab0 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -80,6 +80,40 @@  static int mov_read_mfra(MOVContext *c, AVIOContext *f);
 static int64_t add_ctts_entry(MOVCtts** ctts_data, unsigned int* ctts_count, unsigned int* allocated_size,
                               int count, int duration);
 
+/**  Check if the box size meets the requirements passed in limit and constraint_type.
+ *   If input avio_size is valid, it checks if box size appears to be available.
+ *
+ *   constraint_type may be
+ *   0  if the box size has to be exactly equal to limit
+ *  -1  if the box size has to be at most limit
+ *   1  if the box size has to be at least limit
+ *
+ *   Returns 0 if size meets requirements.
+ */
+static int validate_box_size(MOVContext *c, MOVAtom atom, AVIOContext *pb,
+                             int64_t pos, int64_t limit, int constraint_type)
+{
+    int size_fit;
+    int64_t input_size = avio_size(pb);
+
+    if (input_size > 0 &&
+        input_size - pos < atom.size) {
+        av_log(c->fc, AV_LOG_ERROR, "Box %s is truncated\n", av_fourcc2str(atom.type));
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (FFABS(constraint_type) > 1)
+        return AVERROR_BUG;
+
+    switch(constraint_type) {
+    case  0: size_fit = atom.size == limit; break;
+    case -1: size_fit = atom.size <= limit; break;
+    case  1: size_fit = atom.size >= limit; break;
+    }
+
+   return !size_fit;
+}
+
 static int mov_metadata_track_or_disc_number(MOVContext *c, AVIOContext *pb,
                                              unsigned len, const char *key)
 {