[FFmpeg-cvslog] Fix potential pointer arithmetic overflows in the Electronic Arts CMV decoder .

[Laurent Aimar]

ffmpeg | branch: release/0.8 | Laurent Aimar <fenrir at videolan.org> | Sat Oct  1 00:44:59 2011 +0200| [df39708269f5c298dea08d63de37f701295a17d3] | committer: Michael Niedermayer

Fix potential pointer arithmetic overflows in the Electronic Arts CMV decoder.

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit e9064c9ce8ed18c3a3aab61e58e663b8f5b0c551)

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=df39708269f5c298dea08d63de37f701295a17d3
---

 libavcodec/eacmv.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavcodec/eacmv.c b/libavcodec/eacmv.c
index 408d948..35701ca 100644
--- a/libavcodec/eacmv.c
+++ b/libavcodec/eacmv.c
@@ -56,7 +56,7 @@ static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *
     unsigned char *dst = s->frame.data[0];
     int i;
 
-    for (i=0; i < s->avctx->height && buf+s->avctx->width<=buf_end; i++) {
+    for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
         memcpy(dst, buf, s->avctx->width);
         dst += s->frame.linesize[0];
         buf += s->avctx->width;
@@ -88,7 +88,7 @@ static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *
 
     i = 0;
     for(y=0; y<s->avctx->height/4; y++)
-    for(x=0; x<s->avctx->width/4 && buf+i<buf_end; x++) {
+    for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
         if (buf[i]==0xFF) {
             unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
             if (raw+16<buf_end && *raw==0xFF) { /* intra */
@@ -122,7 +122,7 @@ static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t
 {
     int pal_start, pal_count, i;
 
-    if(buf+16>=buf_end) {
+    if(buf_end - buf < 16) {
         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
         return;
     }
@@ -139,7 +139,7 @@ static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t
     pal_count = AV_RL16(&buf[14]);
 
     buf += 16;
-    for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
+    for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
         s->palette[i] = AV_RB24(buf);
         buf += 3;
     }