[FFmpeg-devel] [PATCH 1/2] avformat/imfdec: do not use filesize when reading XML file

[Marton Balint]

On Sun, 9 Jan 2022, Pierre-Anthony Lemieux wrote:

> On Sat, Jan 8, 2022 at 10:49 AM Marton Balint <cus at passwd.hu> wrote:
>>
>>
>>
>> On Sat, 1 Jan 2022, Marton Balint wrote:
>>
>>> Signed-off-by: Marton Balint <cus at passwd.hu>
>>> ---
>>> libavformat/imfdec.c | 15 ++++-----------
>>> 1 file changed, 4 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/libavformat/imfdec.c b/libavformat/imfdec.c
>>> index f17064cfcd..ef1e7cf206 100644
>>> --- a/libavformat/imfdec.c
>>> +++ b/libavformat/imfdec.c
>>> @@ -73,8 +73,6 @@
>>> #include <inttypes.h>
>>> #include <libxml/parser.h>
>>>
>>> -#define MAX_BPRINT_READ_SIZE (UINT_MAX - 1)
>>> -#define DEFAULT_ASSETMAP_SIZE 8 * 1024
>>> #define AVRATIONAL_FORMAT "%d/%d"
>>> #define AVRATIONAL_ARG(rational) rational.num, rational.den
>>>
>>> @@ -279,7 +277,6 @@ static int parse_assetmap(AVFormatContext *s, const char *url)
>>>     const char *base_url;
>>>     char *tmp_str = NULL;
>>>     int ret;
>>> -    int64_t filesize;
>>>
>>>     av_log(s, AV_LOG_DEBUG, "Asset Map URL: %s\n", url);
>>>
>>> @@ -289,13 +286,10 @@ static int parse_assetmap(AVFormatContext *s, const char *url)
>>>     if (ret < 0)
>>>         return ret;
>>>
>>> -    filesize = avio_size(in);
>>> -    filesize = filesize > 0 ? filesize : DEFAULT_ASSETMAP_SIZE;
>>> +    av_bprint_init(&buf, 0, INT_MAX); // xmlReadMemory uses integer length
>>>
>>> -    av_bprint_init(&buf, filesize + 1, AV_BPRINT_SIZE_UNLIMITED);
>>> -
>>> -    ret = avio_read_to_bprint(in, &buf, MAX_BPRINT_READ_SIZE);
>>> -    if (ret < 0 || !avio_feof(in) || buf.len == 0) {
>>> +    ret = avio_read_to_bprint(in, &buf, SIZE_MAX);
>>> +    if (ret < 0 || !avio_feof(in)) {
>>>         av_log(s, AV_LOG_ERROR, "Unable to read to asset map '%s'\n", url);
>>>         if (ret == 0)
>>>             ret = AVERROR_INVALIDDATA;
>>> @@ -311,8 +305,7 @@ static int parse_assetmap(AVFormatContext *s, const char *url)
>>>     }
>>>     base_url = av_dirname(tmp_str);
>>>
>>> -    filesize = buf.len;
>>> -    doc = xmlReadMemory(buf.str, filesize, url, NULL, 0);
>>> +    doc = xmlReadMemory(buf.str, buf.len, url, NULL, 0);
>>>
>>>     ret = parse_imf_asset_map_from_xml_dom(s, doc, &c->asset_locator_map, base_url);
>>>     if (!ret)
>>
>> Will apply the series tomorrow.
>
> It looks like the same code exists at libavformat/imf_cpl.c [1].
>
> [1] https://github.com/FFmpeg/FFmpeg/blob/ce4d459db186a7d8ac842685cd6256c9ac1b7f25/libavformat/imf_cpl.c#L795
>
> Does it need to be changed there as well?

Yes, preferably that should be changed as well. No that it matters too 
much, it just better/simpler not to depend on filesize.

Thanks,
Marton