From ae7e5e7a54208c5ed4b35921850dd29e2e7a34f7 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Mon, 4 Apr 2022 15:44:37 +0100
Subject: [PATCH] improve fail on too many warings

thanks lovell, see https://github.com/libvips/libvips/commit/89bd46d1c4e0465974b886ef5b5021e988f111a2#commitcomment-70409015
---
 libvips/foreign/jpeg2vips.c | 11 +++++++++++
 libvips/foreign/vips2jpeg.c | 14 ++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/libvips/foreign/jpeg2vips.c b/libvips/foreign/jpeg2vips.c
index e3f69ef6..b0b002a3 100644
--- a/libvips/foreign/jpeg2vips.c
+++ b/libvips/foreign/jpeg2vips.c
@@ -494,6 +494,17 @@ read_jpeg_header( ReadJpeg *jpeg, VipsImage *out )
 	 */
 	jpeg->eman.pub.trace_level = 3;
 
+	/* Here for longjmp() from vips__new_error_exit() during
+	 * jpeg_read_header(),
+	 */
+	if( setjmp( jpeg->eman.jmp ) ) {
+#ifdef DEBUG
+		printf( "read_jpeg_header: longjmp() exit\n" ); 
+#endif /*DEBUG*/
+
+		return( -1 );
+	}
+
 	/* Read JPEG header. libjpeg will set out_color_space sanely for us 
 	 * for YUV YCCK etc.
 	 */
diff --git a/libvips/foreign/vips2jpeg.c b/libvips/foreign/vips2jpeg.c
index bfe99f4f..feaf92f4 100644
--- a/libvips/foreign/vips2jpeg.c
+++ b/libvips/foreign/vips2jpeg.c
@@ -165,16 +165,18 @@
 void
 vips__new_output_message( j_common_ptr cinfo )
 {
+	ErrorManager *eman = (ErrorManager *) cinfo->err;
+
 	/* Some DoS attacks use jpg files with thousands of warnings. Try to
 	 * limit the effect these have.
 	 */
-	if( cinfo->err->num_warnings >= 20 ) {
-		if( cinfo->err->num_warnings == 20 ) {
-			vips_error( "VipsJpeg", 
-				"%s", _( "too many warnings" ) );
-		}
+	if( cinfo->err->num_warnings >= 100 ) {
+		vips_error( "VipsJpeg", "%s", _( "too many warnings" ) );
 
-		jpeg_abort( cinfo );
+		/* Bail out of jpeg load (ugh!). We have to hope our caller
+		 * has set this up.
+		 */
+		longjmp( eman->jmp, 1 );
 	}
 	else {
 		char buffer[JMSG_LENGTH_MAX];