tiff: Prevent overreads in the type_sizes array.
authorAlex Converse <alex.converse@gmail.com>
Thu, 23 Feb 2012 18:47:50 +0000 (10:47 -0800)
committerReinhard Tartler <siretart@tauware.de>
Sun, 26 Feb 2012 09:03:16 +0000 (10:03 +0100)
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
(cherry picked from commit 447363870f2f91e125e07ac2d0820359a5d86b06)

Signed-off-by: Anton Khirnov <anton@khirnov.net>
libavcodec/tiff.c

index a88d0f9..6810f81 100644 (file)
@@ -289,6 +289,11 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start, const uint8_t *
     count = tget_long(&buf, s->le);
     off = tget_long(&buf, s->le);
 
+    if (type == 0 || type >= FF_ARRAY_ELEMS(type_sizes)) {
+        av_log(s->avctx, AV_LOG_DEBUG, "Unknown tiff type (%u) encountered\n", type);
+        return 0;
+    }
+
     if(count == 1){
         switch(type){
         case TIFF_BYTE:
@@ -310,10 +315,12 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start, const uint8_t *
             value = -1;
             buf = start + off;
         }
-    }else if(type_sizes[type] * count <= 4){
-        buf -= 4;
-    }else{
-        buf = start + off;
+    } else {
+        if (count <= 4 && type_sizes[type] * count <= 4) {
+            buf -= 4;
+        } else {
+            buf = start + off;
+        }
     }
 
     if(buf && (buf < start || buf > end_buf)){