[FFmpeg-cvslog] ea: check chunk_size for validity.

[Ronald S. Bultje]

ffmpeg | branch: release/0.5 | Ronald S. Bultje <rsbultje at gmail.com> | Fri May  4 16:06:26 2012 -0700| [8ba939fcda58a2af781d8050bd7108b9e951eeaf] | committer: Reinhard Tartler

ea: check chunk_size for validity.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
(cherry picked from commit 273e6af47b38391f2bcc157cca0423fe7fcbf55c)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>
(cherry picked from commit 6a86b705e1d4b72f0dddfbe23ad3eed9947001d5)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>
(cherry picked from commit e74bc64dd376c4691a610ba62a66ed30affc97ec)

Conflicts:

	libavformat/electronicarts.c
(cherry picked from commit 38c45adfca299e3d96c07a700032695ec7ff2aeb)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8ba939fcda58a2af781d8050bd7108b9e951eeaf
---

 libavformat/electronicarts.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavformat/electronicarts.c b/libavformat/electronicarts.c
index fe19e70..ad63c56 100644
--- a/libavformat/electronicarts.c
+++ b/libavformat/electronicarts.c
@@ -448,12 +448,17 @@ static int ea_read_packet(AVFormatContext *s,
 
     while (!packet_read) {
         chunk_type = get_le32(pb);
-        chunk_size = (ea->big_endian ? get_be32(pb) : get_le32(pb)) - 8;
+        chunk_size = ea->big_endian ? get_be32(pb) : get_le32(pb);
+        if (chunk_size <= 8)
+            return AVERROR_INVALIDDATA;
+        chunk_size -= 8;
 
         switch (chunk_type) {
         /* audio data */
         case ISNh_TAG:
             /* header chunk also contains data; skip over the header portion*/
+            if (chunk_size < 32)
+                return AVERROR_INVALIDDATA;
             url_fskip(pb, 32);
             chunk_size -= 32;
         case ISNd_TAG: