[FFmpeg-devel,2/3] avformat/mov: Fix parsing of saio/siaz atoms in encrypted content.

From 3c60b4bf10f8711a8db70bf74cc5e4b8ce3d50e0 Mon Sep 17 00:00:00 2001
From: Jacob Trimble <modmaker@google.com>
Date: Wed, 6 Dec 2017 16:17:54 -0800
Subject: [PATCH] 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  | 186 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 192 insertions(+)

diff --git a/libavformat/isom.h b/libavformat/isom.h
index 3794b1f0fd..3de8053da2 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -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 {
diff --git a/libavformat/mov.c b/libavformat/mov.c
index eb3fb71e2a..9ff4a809b7 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -5835,6 +5835,177 @@  static int mov_read_senc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     return 0;
 }
 
+static int mov_parse_auxiliary_info(MOVContext *c, MOVStreamContext *sc, AVIOContext *pb, MOVEncryptionIndex *encryption_index)
+{
+    AVEncryptionInfo **sample;
+    int64_t prev_pos;
+    size_t sample_count, sample_info_size, i;
+    int ret = 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;
+    }
+
+    encryption_index->encrypted_samples = av_mallocz_array(sizeof(AVEncryptionInfo*), sample_count);
+    if (!encryption_index->encrypted_samples)
+        return AVERROR(ENOMEM);
+    encryption_index->nb_encrypted_samples = sample_count;
+
+    prev_pos = avio_tell(pb);
+    if (avio_seek(pb, encryption_index->auxiliary_offsets[0], SEEK_SET) != encryption_index->auxiliary_offsets[i]) {
+        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; i++) {
+        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;
+    }
+
+finish:
+    avio_seek(pb, prev_pos, SEEK_SET);
+    return ret;
+}
+
+static int mov_read_saiz(MOVContext *c, AVIOContext *pb, MOVAtom atom)
+{
+    MOVEncryptionIndex *encryption_index;
+    MOVStreamContext *sc;
+    int ret;
+    unsigned int sample_count, has_saiz_type;
+
+    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 */
+    has_saiz_type = avio_rb24(pb) & 0x01;  /* flags */
+    if (has_saiz_type) {
+        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) {
+        if (atom.size - 9 - (has_saiz_type ? 8 : 0) != sample_count) {
+            av_log(c->fc, AV_LOG_ERROR, "incorrect sample_count in saiz\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        encryption_index->auxiliary_info_sizes = av_malloc(sample_count);
+        if (!encryption_index->auxiliary_info_sizes)
+            return AVERROR(ENOMEM);
+        if (avio_read(pb, encryption_index->auxiliary_info_sizes, sample_count) != sample_count) {
+            av_log(c->fc, AV_LOG_ERROR, "failed to read the auxiliary info\n");
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
+    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)
+{
+    MOVEncryptionIndex *encryption_index;
+    MOVStreamContext *sc;
+    int i, ret;
+    unsigned int version, entry_count, has_saio_type;
+
+    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 */
+    has_saio_type = avio_rb24(pb) & 0x01;  /* flags */
+    if (has_saio_type) {
+        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 = (atom.size - 8 - (has_saio_type ? 8 : 0)) / (version == 0 ? 4 : 8);
+    if (avio_rb32(pb) != entry_count) {
+        av_log(c->fc, AV_LOG_ERROR, "incorrect entry_count in saio\n");
+        return AVERROR_INVALIDDATA;
+    }
+    encryption_index->auxiliary_offsets =
+        av_malloc_array(sizeof(*encryption_index->auxiliary_offsets), entry_count);
+    if (!encryption_index->auxiliary_offsets)
+        return AVERROR(ENOMEM);
+    encryption_index->auxiliary_offsets_count = entry_count;
+
+    if (version == 0) {
+        for (i = 0; i < entry_count; i++) {
+          encryption_index->auxiliary_offsets[i] = avio_rb32(pb);
+        }
+    } else {
+        for (i = 0; i < entry_count; i++) {
+          encryption_index->auxiliary_offsets[i] = avio_rb64(pb);
+        }
+    }
+    if (c->frag_index.current >= 0) {
+        for (i = 0; i < entry_count; i++) {
+            encryption_index->auxiliary_offsets[i] += c->fragment.base_data_offset;
+        }
+    }
+
+    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;
@@ -6050,6 +6221,17 @@  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;
@@ -6194,6 +6376,8 @@  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 },
@@ -6589,6 +6773,8 @@  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.rc0.223.g4a4ac83678-goog