From a815ad62502669e9a2b689f6f609eb03008a4ca4 Mon Sep 17 00:00:00 2001 From: Sergei Rogachev Date: Thu, 11 Aug 2016 22:09:30 +0300 Subject: [PATCH] Fix longjmp to invalid address on jpeg init error Libjpeg used in NetSurf for decoding of JPEG images handles exceptions using a pair of non-local jump functions: setjmp() and longjmp(). When a decompression context is created via a call to the function jpeg_create_decompress() the caller passes a structure jpeg_decompress_struct as a parameter. This structure should has a validly initialized jump buffer, so the initialization or other functions called in future can jump to the exception handling context. The jpeg backend of NetSurf now initializes libjpeg mistakenly: jump buffer is filled after the call to jpeg_create_decompress(). It results in jump to random addresses in the case of exception caught during operation of the function jpeg_create_decompress(). The patch moves the initialization of jump buffer before the call to jpeg_create_decompress(). Signed-off-by: Sergei Rogachev --- content/handlers/image/jpeg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/content/handlers/image/jpeg.c b/content/handlers/image/jpeg.c index 278d9e618..5ae9e70cd 100644 --- a/content/handlers/image/jpeg.c +++ b/content/handlers/image/jpeg.c @@ -202,8 +202,8 @@ jpeg_cache_convert(struct content *c) return bitmap; } - jpeg_create_decompress(&cinfo); cinfo.client_data = &setjmp_buffer; + jpeg_create_decompress(&cinfo); /* setup data source */ source_mgr.next_input_byte = source_data; @@ -305,8 +305,8 @@ static bool nsjpeg_convert(struct content *c) return false; } - jpeg_create_decompress(&cinfo); cinfo.client_data = &setjmp_buffer; + jpeg_create_decompress(&cinfo); source_mgr.next_input_byte = (unsigned char *) data; source_mgr.bytes_in_buffer = size; cinfo.src = &source_mgr;