(image-jpeg-p): Don't search beyond length of data.

2 files changed, 6 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 495fc5fa36e..334d3bd462e 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,7 @@
+2003-08-26  John Paul Wallington  <jpw@gnu.org>
+
+        * image.el (image-jpeg-p): Don't search beyond length of data.
+
 2003-08-26  Martin Stjernholm  <bug-cc-mode@gnu.org>
 
         * progmodes/cc-cmds.el (c-electric-brace): Work around for a
diff --git a/lisp/image.el b/lisp/image.el
index 25d05c9902f..5f603ccdd12 100644
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -67,7 +67,8 @@ We accept the tag Exif because that is the same format."
             (when (and (>= code #xe0) (<= code #xef))
               ;; APP0 LEN1 LEN2 "JFIF\0"
               (throw 'jfif
-                     (string-match "JFIF\\|Exif" (substring data i (+ i nbytes)))))
+                     (string-match "JFIF\\|Exif"
+                                   (substring data i (min (+ i nbytes) len)))))
             (setq i (+ i 1 nbytes))))))))