[FFmpeg-devel] [PATCH] lavf/dashdec: support larger manifests

[Steven Liu]

> 2020年5月2日 下午2:33，rcombs <rcombs at rcombs.me> 写道：
> 
> ---
> libavformat/dashdec.c | 29 +++++++++++++++--------------
> 1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
> index 5ba7feb245..bde4b0846d 100644
> --- a/libavformat/dashdec.c
> +++ b/libavformat/dashdec.c
> @@ -29,6 +29,8 @@
> #include "dash.h"
> 
> #define INITIAL_BUFFER_SIZE 32768
> +#define MAX_MANIFEST_SIZE 50 * 1024
> +#define DEFAULT_MANIFEST_SIZE 8 * 1024
> 
> struct fragment {
>     int64_t url_offset;
> @@ -1220,7 +1222,7 @@ static int parse_manifest(AVFormatContext *s, const char *url, AVIOContext *in)
>     int close_in = 0;
>     uint8_t *new_url = NULL;
>     int64_t filesize = 0;
> -    char *buffer = NULL;
> +    AVBPrint buf;
>     AVDictionary *opts = NULL;
>     xmlDoc *doc = NULL;
>     xmlNodePtr root_element = NULL;
> @@ -1254,24 +1256,23 @@ static int parse_manifest(AVFormatContext *s, const char *url, AVIOContext *in)
>     }
> 
>     filesize = avio_size(in);
> -    if (filesize <= 0) {
> -        filesize = 8 * 1024;
> +    if (filesize > MAX_MANIFEST_SIZE) {
> +        av_log(s, AV_LOG_ERROR, "Manifest too large: %"PRId64"\n", filesize);
> +        return AVERROR_INVALIDDATA;
>     }
> 
> -    buffer = av_mallocz(filesize);
> -    if (!buffer) {
> -        av_free(c->base_url);
> -        return AVERROR(ENOMEM);
> -    }
> +    av_bprint_init(&buf, (filesize > 0) ? filesize + 1 : DEFAULT_MANIFEST_SIZE, AV_BPRINT_SIZE_UNLIMITED);
> 
> -    filesize = avio_read(in, buffer, filesize);
> -    if (filesize <= 0) {
> -        av_log(s, AV_LOG_ERROR, "Unable to read to offset '%s'\n", url);
> -        ret = AVERROR_INVALIDDATA;
> +    if ((ret = avio_read_to_bprint(in, &buf, MAX_MANIFEST_SIZE)) < 0 ||
> +        !avio_feof(in) ||
> +        (filesize = buf.len) == 0) {
> +        av_log(s, AV_LOG_ERROR, "Unable to read to manifest '%s'\n", url);
> +        if (ret == 0)
> +            ret = AVERROR_INVALIDDATA;
>     } else {
>         LIBXML_TEST_VERSION
> 
> -        doc = xmlReadMemory(buffer, filesize, c->base_url, NULL, 0);
> +        doc = xmlReadMemory(buf.str, filesize, c->base_url, NULL, 0);
>         root_element = xmlDocGetRootElement(doc);
>         node = root_element;
> 
> @@ -1394,7 +1395,7 @@ cleanup:
>     }
> 
>     av_free(new_url);
> -    av_free(buffer);
> +    av_bprint_finalize(&buf, NULL);
>     if (close_in) {
>         avio_close(in);
>     }
> -- 
> 2.24.1
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LGTM


Thanks

Steven Liu