[FFmpeg-cvslog] oma: better format detection with small probe buffer

[David Goldwich]

ffmpeg | branch: master | David Goldwich <david.goldwich at gmail.com> | Fri Dec  2 05:54:20 2011 +0100| [8ae5eb75df683069b04cf45bfa9d25fbb161c996] | committer: Anton Khirnov

oma: better format detection with small probe buffer

Signed-off-by: David Goldwich <david.goldwich at gmail.com>
Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8ae5eb75df683069b04cf45bfa9d25fbb161c996
---

 libavformat/oma.c |   16 +++++++++++-----
 1 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/libavformat/oma.c b/libavformat/oma.c
index 0d81a43..4f4837d 100644
--- a/libavformat/oma.c
+++ b/libavformat/oma.c
@@ -394,14 +394,20 @@ static int oma_read_probe(AVProbeData *p)
     unsigned tag_len = 0;
 
     buf = p->buf;
-    /* version must be 3 and flags byte zero */
-    if (ff_id3v2_match(buf, ID3v2_EA3_MAGIC) && buf[3] == 3 && !buf[4])
-        tag_len = ff_id3v2_tag_len(buf);
 
-    // This check cannot overflow as tag_len has at most 28 bits
-    if (p->buf_size < tag_len + 5)
+    if (p->buf_size < ID3v2_HEADER_SIZE ||
+        !ff_id3v2_match(buf, ID3v2_EA3_MAGIC) ||
+        buf[3] != 3 || // version must be 3
+        buf[4]) // flags byte zero
         return 0;
 
+    tag_len = ff_id3v2_tag_len(buf);
+
+    /* This check cannot overflow as tag_len has at most 28 bits */
+    if (p->buf_size < tag_len + 5)
+        /* EA3 header comes late, might be outside of the probe buffer */
+        return AVPROBE_SCORE_MAX / 2;
+
     buf += tag_len;
 
     if (!memcmp(buf, "EA3", 3) && !buf[4] && buf[5] == EA3_HEADER_SIZE)