[FFmpeg-devel] [PATCH v3 2/2] avformat: add data_size for ff_hex_to_data()
lance.lmwang at gmail.com
lance.lmwang at gmail.com
Tue May 11 01:38:52 EEST 2021
On Mon, May 10, 2021 at 09:52:48PM +0200, Andreas Rheinhardt wrote:
> lance.lmwang at gmail.com:
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > This prevents OOM in case of data buffer size is insufficient.
>
> OOM?
Yes, it's invalid Out Of Memory access, not no memory available.
What's your suggestion?
>
> >
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> > libavformat/hls.c | 4 +++-
> > libavformat/internal.h | 6 ++++--
> > libavformat/rtpdec_latm.c | 6 ++++--
> > libavformat/rtpdec_mpeg4.c | 6 ++++--
> > libavformat/utils.c | 7 +++++--
> > 5 files changed, 20 insertions(+), 9 deletions(-)
> >
> > diff --git a/libavformat/hls.c b/libavformat/hls.c
> > index 8fc6924..d7d0387 100644
> > --- a/libavformat/hls.c
> > +++ b/libavformat/hls.c
> > @@ -800,7 +800,9 @@ static int parse_playlist(HLSContext *c, const char *url,
> > if (!strcmp(info.method, "SAMPLE-AES"))
> > key_type = KEY_SAMPLE_AES;
> > if (!av_strncasecmp(info.iv, "0x", 2)) {
> > - ff_hex_to_data(iv, info.iv + 2);
> > + ret = ff_hex_to_data(iv, sizeof(iv), info.iv + 2);
> > + if (ret < 0)
> > + goto fail;
> > has_iv = 1;
> > }
> > av_strlcpy(key, info.uri, sizeof(key));
> > diff --git a/libavformat/internal.h b/libavformat/internal.h
> > index d57e63c..3192aca 100644
> > --- a/libavformat/internal.h
> > +++ b/libavformat/internal.h
> > @@ -423,10 +423,12 @@ char *ff_data_to_hex(char *buf, const uint8_t *src, int size, int lowercase);
> > * digits is ignored.
> > *
> > * @param data if non-null, the parsed data is written to this pointer
> > + * @param data_size the data buffer size
> > * @param p the string to parse
> > - * @return the number of bytes written (or to be written, if data is null)
> > + * @return the number of bytes written (or to be written, if data is null),
> > + * or < 0 in case data_size is insufficient if data isn't null.
> > */
> > -int ff_hex_to_data(uint8_t *data, const char *p);
> > +int ff_hex_to_data(uint8_t *data, int data_size, const char *p);
>
> This is unnecessary, as none of the callers need it: The rtpdec users
> call ff_hex_to_data() twice, once to get the necessary size, once to
> write the data. And the hls buffer is already big enough. I only see two
> things that could be improved: Return size_t in ff_hex_to_data() as
> that's the proper type (this includes checks in the callers for whether
> the return type fit into the type of the extradata size)) and making the
> size of the iv automatically match the needed size of (struct keyinfo).iv.
>
> >
> > /**
> > * Add packet to an AVFormatContext's packet_buffer list, determining its
> > diff --git a/libavformat/rtpdec_latm.c b/libavformat/rtpdec_latm.c
> > index 104a00a..cf1d581 100644
> > --- a/libavformat/rtpdec_latm.c
> > +++ b/libavformat/rtpdec_latm.c
> > @@ -91,7 +91,7 @@ static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
> >
> > static int parse_fmtp_config(AVStream *st, const char *value)
> > {
> > - int len = ff_hex_to_data(NULL, value), i, ret = 0;
> > + int len = ff_hex_to_data(NULL, 0, value), i, ret = 0;
> > GetBitContext gb;
> > uint8_t *config;
> > int audio_mux_version, same_time_framing, num_programs, num_layers;
> > @@ -100,7 +100,9 @@ static int parse_fmtp_config(AVStream *st, const char *value)
> > config = av_mallocz(len + AV_INPUT_BUFFER_PADDING_SIZE);
> > if (!config)
> > return AVERROR(ENOMEM);
> > - ff_hex_to_data(config, value);
> > + ret = ff_hex_to_data(config, len, value);
> > + if (ret < 0)
> > + return ret;
> > init_get_bits(&gb, config, len*8);
> > audio_mux_version = get_bits(&gb, 1);
> > same_time_framing = get_bits(&gb, 1);
> > diff --git a/libavformat/rtpdec_mpeg4.c b/libavformat/rtpdec_mpeg4.c
> > index 34c7950..27751df 100644
> > --- a/libavformat/rtpdec_mpeg4.c
> > +++ b/libavformat/rtpdec_mpeg4.c
> > @@ -112,11 +112,13 @@ static void close_context(PayloadContext *data)
> > static int parse_fmtp_config(AVCodecParameters *par, const char *value)
> > {
> > /* decode the hexa encoded parameter */
> > - int len = ff_hex_to_data(NULL, value), ret;
> > + int len = ff_hex_to_data(NULL, 0, value), ret;
> >
> > if ((ret = ff_alloc_extradata(par, len)) < 0)
> > return ret;
> > - ff_hex_to_data(par->extradata, value);
> > + ret = ff_hex_to_data(par->extradata, par->extradata_size, value);
> > + if (ret < 0)
> > + return ret;> return 0;
> > }
> >
> > diff --git a/libavformat/utils.c b/libavformat/utils.c
> > index 9228313..dfe9f4c 100644
> > --- a/libavformat/utils.c
> > +++ b/libavformat/utils.c
> > @@ -4768,7 +4768,7 @@ char *ff_data_to_hex(char *buff, const uint8_t *src, int s, int lowercase)
> > return buff;
> > }
> >
> > -int ff_hex_to_data(uint8_t *data, const char *p)
> > +int ff_hex_to_data(uint8_t *data, int data_size, const char *p)
> > {
> > int c, len, v;
> >
> > @@ -4787,8 +4787,11 @@ int ff_hex_to_data(uint8_t *data, const char *p)
> > break;
> > v = (v << 4) | c;
> > if (v & 0x100) {
> > - if (data)
> > + if (data) {
> > + if (len >= data_size)
> > + return AVERROR(ERANGE);
> > data[len] = v;
> > + }
> > len++;
> > v = 1;
> > }
> >
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
--
Thanks,
Limin Wang
More information about the ffmpeg-devel
mailing list