[FFmpeg-devel] [PATCH v2 03/11] libavformat/asfdec: fix type of value_len

[softworkz <ffmpegagent@gmail.com>]

From: softworkz <softworkz@hotmail.com>

The value_len is an uint32 not an int32 per spec. That
value must not be truncated, neither by casting to int, nor by any
conditional checks, because at the end of get_tag, this value is
needed to move forward in parsing. When the len value gets
modified, the parsing may break.

Signed-off-by: softworkz <softworkz@hotmail.com>
---
 libavformat/asfdec_f.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index d31e1d581d..29b429fee9 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -218,7 +218,7 @@ static uint64_t get_value(AVIOContext *pb, int type, int type2_size)
     }
 }
 
-static void get_tag(AVFormatContext *s, const char *key, int type, int len, int type2_size)
+static void get_tag(AVFormatContext *s, const char *key, int type, uint32_t len, int type2_size)
 {
     ASFContext *asf = s->priv_data;
     char *value = NULL;
@@ -528,7 +528,7 @@ static int asf_read_ext_stream_properties(AVFormatContext *s, int64_t size)
 static int asf_read_content_desc(AVFormatContext *s, int64_t size)
 {
     AVIOContext *pb = s->pb;
-    int len1, len2, len3, len4, len5;
+    uint32_t len1, len2, len3, len4, len5;
 
     len1 = avio_rl16(pb);
     len2 = avio_rl16(pb);
@@ -614,25 +614,23 @@ static int asf_read_metadata(AVFormatContext *s, int64_t size)
 {
     AVIOContext *pb = s->pb;
     ASFContext *asf = s->priv_data;
-    int n, stream_num, name_len_utf16, name_len_utf8, value_len;
+    int n, name_len_utf8;
+    uint16_t stream_num, name_len_utf16, value_type;
+    uint32_t value_len;
     int ret, i;
     n = avio_rl16(pb);
 
     for (i = 0; i < n; i++) {
         uint8_t *name;
-        int value_type;
 
         avio_rl16(pb);  // lang_list_index
-        stream_num = avio_rl16(pb);
-        name_len_utf16 = avio_rl16(pb);
-        value_type = avio_rl16(pb); /* value_type */
-        value_len  = avio_rl32(pb);
+        stream_num     = (uint16_t)avio_rl16(pb);
+        name_len_utf16 = (uint16_t)avio_rl16(pb);
+        value_type     = (uint16_t)avio_rl16(pb); /* value_type */
+        value_len      = avio_rl32(pb);
 
-        if (value_len < 0 || value_len > UINT16_MAX)
-            return AVERROR_INVALIDDATA;
-
-        name_len_utf8 = 2*name_len_utf16 + 1;
-        name          = av_malloc(name_len_utf8);
+        name_len_utf8  = 2 * name_len_utf16 + 1;
+        name           = av_malloc(name_len_utf8);
         if (!name)
             return AVERROR(ENOMEM);
 
-- 
ffmpeg-codebot

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