Mp4: skip tracks shorter than seek position (ticket nginx#414).

Mp4 module does not check movie and track durations when reading file. Instead it generates errors when track metadata is shorter than seek position. Now such tracks are skipped and movie duration check is performed at file read stage.
skyend · Jan 29, 2014 · 88f9b41 · 88f9b41
1 parent 870733e
commit 88f9b41
Showing 1 changed file with 31 additions and 6 deletions.
diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
@@ -1208,7 +1208,7 @@ ngx_http_mp4_read_mvhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
     u_char                 *atom_header;
     size_t                  atom_size;
     uint32_t                timescale;
-    uint64_t                duration;
+    uint64_t                duration, start_time;
     ngx_buf_t              *atom;
     ngx_mp4_mvhd_atom_t    *mvhd_atom;
     ngx_mp4_mvhd64_atom_t  *mvhd64_atom;
@@ -1251,7 +1251,16 @@ ngx_http_mp4_read_mvhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
                    "mvhd timescale:%uD, duration:%uL, time:%.3fs",
                    timescale, duration, (double) duration / timescale);
 
-    duration -= (uint64_t) mp4->start * timescale / 1000;
+    start_time = (uint64_t) mp4->start * timescale / 1000;
+
+    if (duration < start_time) {
+        ngx_log_error(NGX_LOG_ERR, mp4->file.log, 0,
+                      "\"%s\" mp4 start time exceeds file duration",
+                      mp4->file.name.data);
+        return NGX_ERROR;
+    }
+
+    duration -= start_time;
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
                    "mvhd new duration:%uL, time:%.3fs",
@@ -1398,7 +1407,7 @@ ngx_http_mp4_read_tkhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
 {
     u_char                 *atom_header;
     size_t                  atom_size;
-    uint64_t                duration;
+    uint64_t                duration, start_time;
     ngx_buf_t              *atom;
     ngx_http_mp4_trak_t    *trak;
     ngx_mp4_tkhd_atom_t    *tkhd_atom;
@@ -1438,7 +1447,15 @@ ngx_http_mp4_read_tkhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
                    "tkhd duration:%uL, time:%.3fs",
                    duration, (double) duration / mp4->timescale);
 
-    duration -= (uint64_t) mp4->start * mp4->timescale / 1000;
+    start_time = (uint64_t) mp4->start * mp4->timescale / 1000;
+
+    if (duration < start_time) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
+                       "tkhd duration is less than start time");
+        return NGX_DECLINED;
+    }
+
+    duration -= start_time;
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
                    "tkhd new duration:%uL, time:%.3fs",
@@ -1541,7 +1558,7 @@ ngx_http_mp4_read_mdhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
     u_char                 *atom_header;
     size_t                  atom_size;
     uint32_t                timescale;
-    uint64_t                duration;
+    uint64_t                duration, start_time;
     ngx_buf_t              *atom;
     ngx_http_mp4_trak_t    *trak;
     ngx_mp4_mdhd_atom_t    *mdhd_atom;
@@ -1583,7 +1600,15 @@ ngx_http_mp4_read_mdhd_atom(ngx_http_mp4_file_t *mp4, uint64_t atom_data_size)
                    "mdhd timescale:%uD, duration:%uL, time:%.3fs",
                    timescale, duration, (double) duration / timescale);
 
-    duration -= (uint64_t) mp4->start * timescale / 1000;
+    start_time = (uint64_t) mp4->start * timescale / 1000;
+
+    if (duration < start_time) {
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
+                       "mdhd duration is less than start time");
+        return NGX_DECLINED;
+    }
+
+    duration -= start_time;
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, mp4->file.log, 0,
                    "mdhd new duration:%uL, time:%.3fs",