From 76c6870513481c14c5c134f1b8e7e9a91e17e6b5 Mon Sep 17 00:00:00 2001
From: Jacob Trimble <modmaker@google.com>
Date: Wed, 6 Dec 2017 16:17:54 -0800
Subject: [PATCH 2/3] avformat/mov: Fix parsing of saio/siaz atoms in encrypted
content.
This doesn't support saio atoms with more than one offset.
Signed-off-by: Jacob Trimble <modmaker@google.com>
---
libavformat/isom.h | 6 ++
libavformat/mov.c | 237 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 243 insertions(+)
@@ -114,6 +114,12 @@ typedef struct MOVEncryptionIndex {
// settings will be used.
unsigned int nb_encrypted_samples;
AVEncryptionInfo **encrypted_samples;
+
+ uint8_t* auxiliary_info_sizes;
+ size_t auxiliary_info_sample_count;
+ uint8_t auxiliary_info_default_size;
+ size_t* auxiliary_offsets; ///< Absolute seek position
+ size_t auxiliary_offsets_count;
} MOVEncryptionIndex;
typedef struct MOVFragmentStreamInfo {
@@ -5863,6 +5863,228 @@ end:
return ret;
}
+static int mov_parse_auxiliary_info(MOVContext *c, MOVStreamContext *sc, AVIOContext *pb, MOVEncryptionIndex *encryption_index)
+{
+ AVEncryptionInfo **sample, **encrypted_samples;
+ int64_t prev_pos;
+ size_t sample_count, sample_info_size, i;
+ int ret = 0;
+ unsigned int alloc_size = 0;
+
+ if (encryption_index->nb_encrypted_samples)
+ return 0;
+ sample_count = encryption_index->auxiliary_info_sample_count;
+ if (encryption_index->auxiliary_offsets_count != 1) {
+ av_log(c->fc, AV_LOG_ERROR, "Multiple auxiliary info chunks are not supported\n");
+ return AVERROR_PATCHWELCOME;
+ }
+ if (sample_count >= INT_MAX / sizeof(*encrypted_samples))
+ return AVERROR(ENOMEM);
+
+ prev_pos = avio_tell(pb);
+ if (!(pb->seekable & AVIO_SEEKABLE_NORMAL) ||
+ avio_seek(pb, encryption_index->auxiliary_offsets[0], SEEK_SET) != encryption_index->auxiliary_offsets[0]) {
+ av_log(c->fc, AV_LOG_INFO, "Failed to seek for auxiliary info, will only parse senc atoms for encryption info\n");
+ goto finish;
+ }
+
+ for (i = 0; i < sample_count && !pb->eof_reached; i++) {
+ unsigned int min_samples = FFMIN(FFMAX(i, 1024 * 1024), sample_count);
+ encrypted_samples = av_fast_realloc(encryption_index->encrypted_samples, &alloc_size,
+ min_samples * sizeof(*encrypted_samples));
+ if (!encrypted_samples) {
+ ret = AVERROR(ENOMEM);
+ goto finish;
+ }
+ encryption_index->encrypted_samples = encrypted_samples;
+
+ sample = &encryption_index->encrypted_samples[i];
+ sample_info_size = encryption_index->auxiliary_info_default_size
+ ? encryption_index->auxiliary_info_default_size
+ : encryption_index->auxiliary_info_sizes[i];
+
+ ret = mov_read_sample_encryption_info(c, pb, sc, sample, sample_info_size > sc->cenc.per_sample_iv_size);
+ if (ret < 0)
+ goto finish;
+ }
+ if (pb->eof_reached) {
+ av_log(c->fc, AV_LOG_ERROR, "Hit EOF while reading auxiliary info\n");
+ ret = AVERROR_INVALIDDATA;
+ } else {
+ encryption_index->nb_encrypted_samples = sample_count;
+ }
+
+finish:
+ avio_seek(pb, prev_pos, SEEK_SET);
+ if (ret < 0) {
+ for (; i > 0; i--) {
+ av_encryption_info_free(encryption_index->encrypted_samples[i - 1]);
+ }
+ av_freep(&encryption_index->encrypted_samples);
+ }
+ return ret;
+}
+
+/**
+ * Tries to read the given number of bytes from the stream and puts it in a
+ * newly allocated buffer. This reads in small chunks to avoid allocating large
+ * memory if the file contains an invalid/malicious size value.
+ */
+static int mov_try_read_block(AVIOContext *pb, size_t size, uint8_t **data)
+{
+ const unsigned int block_size = 1024 * 1024;
+ uint8_t *buffer = NULL;
+ unsigned int alloc_size = 0, offset = 0;
+ while (offset < size) {
+ unsigned int new_size =
+ alloc_size >= INT_MAX - block_size ? INT_MAX : alloc_size + block_size;
+ uint8_t *new_buffer = av_fast_realloc(buffer, &alloc_size, new_size);
+ unsigned int to_read = FFMIN(size, alloc_size) - offset;
+ if (!new_buffer) {
+ av_free(buffer);
+ return AVERROR(ENOMEM);
+ }
+ buffer = new_buffer;
+
+ if (avio_read(pb, buffer + offset, to_read) != to_read) {
+ av_free(buffer);
+ return AVERROR_INVALIDDATA;
+ }
+ offset += to_read;
+ }
+
+ *data = buffer;
+ return 0;
+}
+
+static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
+{
+ MOVEncryptionIndex *encryption_index;
+ MOVStreamContext *sc;
+ int ret;
+ unsigned int sample_count;
+
+ ret = get_current_encryption_info(c, &encryption_index, &sc);
+ if (ret != 1)
+ return ret;
+
+ if (encryption_index->nb_encrypted_samples) {
+ // This can happen if we have both saio/saiz and senc atoms.
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring duplicate encryption info in saiz\n");
+ return 0;
+ }
+
+ if (encryption_index->auxiliary_info_sample_count) {
+ av_log(c->fc, AV_LOG_ERROR, "Duplicate saiz atom\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ avio_r8(pb); /* version */
+ if (avio_rb24(pb) & 0x01) { /* flags */
+ if (avio_rb32(pb) != sc->cenc.default_encrypted_sample->scheme) {
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring saiz box with non-zero aux_info_type\n");
+ return 0;
+ }
+ if (avio_rb32(pb) != 0) {
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring saiz box with non-zero aux_info_type_parameter\n");
+ return 0;
+ }
+ }
+
+ encryption_index->auxiliary_info_default_size = avio_r8(pb);
+ sample_count = avio_rb32(pb);
+ encryption_index->auxiliary_info_sample_count = sample_count;
+
+ if (encryption_index->auxiliary_info_default_size == 0) {
+ ret = mov_try_read_block(pb, sample_count, &encryption_index->auxiliary_info_sizes);
+ if (ret < 0) {
+ av_log(c->fc, AV_LOG_ERROR, "Failed to read the auxiliary info\n");
+ return ret;
+ }
+ }
+
+ if (encryption_index->auxiliary_offsets_count) {
+ return mov_parse_auxiliary_info(c, sc, pb, encryption_index);
+ }
+
+ return 0;
+}
+
+static int mov_read_saio(MOVContext *c, AVIOContext *pb, MOVAtom atom)
+{
+ uint64_t *auxiliary_offsets;
+ MOVEncryptionIndex *encryption_index;
+ MOVStreamContext *sc;
+ int i, ret;
+ unsigned int version, entry_count, alloc_size = 0;
+
+ ret = get_current_encryption_info(c, &encryption_index, &sc);
+ if (ret != 1)
+ return ret;
+
+ if (encryption_index->nb_encrypted_samples) {
+ // This can happen if we have both saio/saiz and senc atoms.
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring duplicate encryption info in saio\n");
+ return 0;
+ }
+
+ if (encryption_index->auxiliary_offsets_count) {
+ av_log(c->fc, AV_LOG_ERROR, "Duplicate saio atom\n");
+ return AVERROR_INVALIDDATA;
+ }
+
+ version = avio_r8(pb); /* version */
+ if (avio_rb24(pb) & 0x01) { /* flags */
+ if (avio_rb32(pb) != sc->cenc.default_encrypted_sample->scheme) {
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring saio box with non-zero aux_info_type\n");
+ return 0;
+ }
+ if (avio_rb32(pb) != 0) {
+ av_log(c->fc, AV_LOG_DEBUG, "Ignoring saio box with non-zero aux_info_type_parameter\n");
+ return 0;
+ }
+ }
+
+ entry_count = avio_rb32(pb);
+ if (entry_count >= INT_MAX / sizeof(*auxiliary_offsets))
+ return AVERROR(ENOMEM);
+
+ for (i = 0; i < entry_count && !pb->eof_reached; i++) {
+ unsigned int min_offsets = FFMIN(FFMAX(i, 1024), entry_count);
+ auxiliary_offsets = av_fast_realloc(
+ encryption_index->auxiliary_offsets, &alloc_size,
+ min_offsets * sizeof(*auxiliary_offsets));
+ if (!auxiliary_offsets) {
+ av_freep(&encryption_index->auxiliary_offsets);
+ return AVERROR(ENOMEM);
+ }
+ encryption_index->auxiliary_offsets = auxiliary_offsets;
+
+ if (version == 0) {
+ encryption_index->auxiliary_offsets[i] = avio_rb32(pb);
+ } else {
+ encryption_index->auxiliary_offsets[i] = avio_rb64(pb);
+ }
+ if (c->frag_index.current >= 0) {
+ encryption_index->auxiliary_offsets[i] += c->fragment.base_data_offset;
+ }
+ }
+
+ if (pb->eof_reached) {
+ av_log(c->fc, AV_LOG_ERROR, "Hit EOF while reading saio\n");
+ av_freep(&encryption_index->auxiliary_offsets);
+ return AVERROR_INVALIDDATA;
+ }
+
+ encryption_index->auxiliary_offsets_count = entry_count;
+
+ if (encryption_index->auxiliary_info_sample_count) {
+ return mov_parse_auxiliary_info(c, sc, pb, encryption_index);
+ }
+
+ return 0;
+}
+
static int mov_read_schm(MOVContext *c, AVIOContext *pb, MOVAtom atom)
{
AVStream *st;
@@ -6078,6 +6300,17 @@ static int cenc_filter(MOVContext *mov, MOVStreamContext *sc, AVPacket *pkt, int
}
if (encryption_index) {
+ if (encryption_index->auxiliary_info_sample_count &&
+ !encryption_index->nb_encrypted_samples) {
+ av_log(mov->fc, AV_LOG_ERROR, "saiz atom found without saio\n");
+ return AVERROR_INVALIDDATA;
+ }
+ if (encryption_index->auxiliary_offsets_count &&
+ !encryption_index->nb_encrypted_samples) {
+ av_log(mov->fc, AV_LOG_ERROR, "saio atom found without saiz\n");
+ return AVERROR_INVALIDDATA;
+ }
+
if (!encryption_index->nb_encrypted_samples) {
// Full-sample encryption with default settings.
encrypted_sample = sc->cenc.default_encrypted_sample;
@@ -6222,6 +6455,8 @@ static const MOVParseTableEntry mov_default_parse_table[] = {
{ MKTAG('s','i','n','f'), mov_read_default },
{ MKTAG('f','r','m','a'), mov_read_frma },
{ MKTAG('s','e','n','c'), mov_read_senc },
+{ MKTAG('s','a','i','z'), mov_read_saiz },
+{ MKTAG('s','a','i','o'), mov_read_saio },
{ MKTAG('s','c','h','m'), mov_read_schm },
{ MKTAG('s','c','h','i'), mov_read_default },
{ MKTAG('t','e','n','c'), mov_read_tenc },
@@ -6617,6 +6852,8 @@ static void mov_free_encryption_index(MOVEncryptionIndex **index) {
av_encryption_info_free((*index)->encrypted_samples[i]);
}
av_freep(&(*index)->encrypted_samples);
+ av_freep(&(*index)->auxiliary_info_sizes);
+ av_freep(&(*index)->auxiliary_offsets);
av_freep(index);
}
--
2.16.0.rc1.238.g530d649a79-goog