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h264_mp4toannexb: Stop reallocating the output buffer 

Up until now, h264_mp4toannexb would grow the output packet's buffer by
the desired amount every time another NAL unit of the input packet has
been read; this commit changes this: The input buffer is now essentially
parsed twice, once to determine the final size of the output packet and
once to write the output packet's data.

Fixes: Timeout
Fixes: 19322/clusterfuzz-testcase-minimized-ffmpeg_BSF_H264_MP4TOANNEXB_fuzzer-5688407821123584

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
tags/n4.3
Andreas Rheinhardt Michael Niedermayer 5 years ago
parent
84c87e41a6
commit
cb47c6c614
1 changed files with 72 additions and 52 deletions
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  1. +72
    -52
      libavcodec/h264_mp4toannexb_bsf.c

+ 72
- 52
libavcodec/h264_mp4toannexb_bsf.c View File

@@ -42,27 +42,23 @@ typedef struct H264BSFContext {
int extradata_parsed;
} H264BSFContext;

static int alloc_and_copy(AVPacket *out,
const uint8_t *in, uint32_t in_size, int ps)
static void count_or_copy(uint8_t **out, uint64_t *out_size,
const uint8_t *in, int in_size, int ps, int copy)
{
uint32_t offset = out->size;
uint8_t start_code_size = ps < 0 ? 0 : offset == 0 || ps ? 4 : 3;
int err;
uint8_t start_code_size = ps < 0 ? 0 : *out_size == 0 || ps ? 4 : 3;

err = av_grow_packet(out, in_size + start_code_size);
if (err < 0)
return err;

memcpy(out->data + start_code_size + offset, in, in_size);
if (copy) {
memcpy(*out + start_code_size, in, in_size);
if (start_code_size == 4) {
AV_WB32(out->data + offset, 1);
AV_WB32(*out, 1);
} else if (start_code_size) {
(out->data + offset)[0] =
(out->data + offset)[1] = 0;
(out->data + offset)[2] = 1;
(*out)[0] =
(*out)[1] = 0;
(*out)[2] = 1;
}

return 0;
*out += start_code_size + in_size;
}
*out_size += start_code_size + in_size;
}

static int h264_extradata_to_annexb(AVBSFContext *ctx, const int padding)
@@ -169,15 +165,17 @@ static int h264_mp4toannexb_init(AVBSFContext *ctx)
return 0;
}

static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
{
H264BSFContext *s = ctx->priv_data;

AVPacket *in;
uint8_t unit_type;
uint8_t unit_type, new_idr, sps_seen, pps_seen;
int32_t nal_size;
const uint8_t *buf;
const uint8_t *buf_end;
uint8_t *out;
uint64_t out_size;
int ret = 0, i;

ret = ff_bsf_get_packet(ctx, &in);
@@ -186,14 +184,23 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)

/* nothing to filter */
if (!s->extradata_parsed) {
av_packet_move_ref(out, in);
av_packet_move_ref(opkt, in);
av_packet_free(&in);
return 0;
}

buf = in->data;
buf_end = in->data + in->size;

#define LOG_ONCE(...) \
if (j) \
av_log(__VA_ARGS__)
for (int j = 0; j < 2; j++) {
buf = in->data;
new_idr = s->new_idr;
sps_seen = s->idr_sps_seen;
pps_seen = s->idr_pps_seen;
out_size = 0;

do {
ret= AVERROR(EINVAL);
if (buf + s->length_size > buf_end)
@@ -209,20 +216,16 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
goto fail;

if (unit_type == H264_NAL_SPS)
s->idr_sps_seen = s->new_idr = 1;
sps_seen = new_idr = 1;
else if (unit_type == H264_NAL_PPS) {
s->idr_pps_seen = s->new_idr = 1;
pps_seen = new_idr = 1;
/* if SPS has not been seen yet, prepend the AVCC one to PPS */
if (!s->idr_sps_seen) {
if (!sps_seen) {
if (!s->sps_size)
av_log(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
LOG_ONCE(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
else {
if ((ret = alloc_and_copy(out,
s->sps,
s->sps_size,
-1)) < 0)
goto fail;
s->idr_sps_seen = 1;
count_or_copy(&out, &out_size, s->sps, s->sps_size, -1, j);
sps_seen = 1;
}
}
}
@@ -230,44 +233,61 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *out)
/* if this is a new IDR picture following an IDR picture, reset the idr flag.
* Just check first_mb_in_slice to be 0 as this is the simplest solution.
* This could be checking idr_pic_id instead, but would complexify the parsing. */
if (!s->new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
s->new_idr = 1;
if (!new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
new_idr = 1;

/* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && !s->idr_sps_seen && !s->idr_pps_seen) {
if (ctx->par_out->extradata && (ret=alloc_and_copy(out,
ctx->par_out->extradata, ctx->par_out->extradata_size,
-1)) < 0)
goto fail;
s->new_idr = 0;
if (new_idr && unit_type == H264_NAL_IDR_SLICE && !sps_seen && !pps_seen) {
if (ctx->par_out->extradata)
count_or_copy(&out, &out_size, ctx->par_out->extradata,
ctx->par_out->extradata_size, -1, j);
new_idr = 0;
/* if only SPS has been seen, also insert PPS */
} else if (s->new_idr && unit_type == H264_NAL_IDR_SLICE && s->idr_sps_seen && !s->idr_pps_seen) {
} else if (new_idr && unit_type == H264_NAL_IDR_SLICE && sps_seen && !pps_seen) {
if (!s->pps_size) {
av_log(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
} else if ((ret = alloc_and_copy(out,
s->pps, s->pps_size,
-1)) < 0)
goto fail;
LOG_ONCE(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
} else {
count_or_copy(&out, &out_size, s->pps, s->pps_size, -1, j);
}
}

if ((ret=alloc_and_copy(out, buf, nal_size, unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)) < 0)
goto fail;
if (!s->new_idr && unit_type == H264_NAL_SLICE) {
s->new_idr = 1;
s->idr_sps_seen = 0;
s->idr_pps_seen = 0;
count_or_copy(&out, &out_size, buf, nal_size,
unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS, j);
if (!new_idr && unit_type == H264_NAL_SLICE) {
new_idr = 1;
sps_seen = 0;
pps_seen = 0;
}

buf += nal_size;
} while (buf < buf_end);

ret = av_packet_copy_props(out, in);
if (!j) {
if (out_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
ret = av_new_packet(opkt, out_size);
if (ret < 0)
goto fail;
out = opkt->data;
}
}
#undef LOG_ONCE

av_assert1(out_size == opkt->size);

s->new_idr = new_idr;
s->idr_sps_seen = sps_seen;
s->idr_pps_seen = pps_seen;

ret = av_packet_copy_props(opkt, in);
if (ret < 0)
goto fail;

fail:
if (ret < 0)
av_packet_unref(out);
av_packet_unref(opkt);
av_packet_free(&in);

return ret;


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