From 648c9eb0b5eb6ddfef70299fcf19a8c323913e44 Mon Sep 17 00:00:00 2001 From: Nigel Tao Date: Tue, 18 Sep 2012 21:57:33 +1000 Subject: [PATCH] image/jpeg: ignore an incorrect but harmless trailing restart marker. Fixes #4084. R=r CC=golang-dev https://golang.org/cl/6526043 --- src/pkg/image/jpeg/reader.go | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/pkg/image/jpeg/reader.go b/src/pkg/image/jpeg/reader.go index 652dc5f6b5..5ed142a6c6 100644 --- a/src/pkg/image/jpeg/reader.go +++ b/src/pkg/image/jpeg/reader.go @@ -403,6 +403,15 @@ func (d *decoder) decode(r io.Reader, configOnly bool) (image.Image, error) { if marker == eoiMarker { // End Of Image. break } + if rst0Marker <= marker && marker <= rst7Marker { + // Figures B.2 and B.16 of the specification suggest that restart markers should + // only occur between Entropy Coded Segments and not after the final ECS. + // However, some encoders may generate incorrect JPEGs with a final restart + // marker. That restart marker will be seen here instead of inside the processSOS + // method, and is ignored as a harmless error. Restart markers have no extra data, + // so we check for this before we read the 16-bit length of the segment. + continue + } // Read the 16-bit length of the segment. The value includes the 2 bytes for the // length itself, so we subtract 2 to get the number of remaining bytes. @@ -431,7 +440,7 @@ func (d *decoder) decode(r io.Reader, configOnly bool) (image.Image, error) { err = d.processSOS(n) case marker == driMarker: // Define Restart Interval. err = d.processDRI(n) - case marker >= app0Marker && marker <= app15Marker || marker == comMarker: // APPlication specific, or COMment. + case app0Marker <= marker && marker <= app15Marker || marker == comMarker: // APPlication specific, or COMment. err = d.ignore(n) default: err = UnsupportedError("unknown marker")