1# HG changeset patch
2# User Petr Písař <ppisar@redhat.com>
3# Date 1560259692 25200
4#      Tue Jun 11 06:28:12 2019 -0700
5# Branch SDL-1.2
6# Node ID f1f5878be5dbf63c1161a8ee52b8a86ece30e552
7# Parent  a936f9bd3e381d67d8ddee8b9243f85799ea4798
8CVE-2019-7635: Reject BMP images with pixel colors out the palette
9If a 1-, 4-, or 8-bit per pixel BMP image declares less used colors
10than the palette offers an SDL_Surface with a palette of the indicated
11number of used colors is created. If some of the image's pixel
12refer to a color number higher then the maximal used colors, a subsequent
13bliting operation on the surface will look up a color past a blit map
14(that is based on the palette) memory. I.e. passing such SDL_Surface
15to e.g. an SDL_DisplayFormat() function will result in a buffer overread in
16a blit function.
17
18This patch fixes it by validing each pixel's color to be less than the
19maximal color number in the palette. A validation failure raises an
20error from a SDL_LoadBMP_RW() function.
21
22CVE-2019-7635
23https://bugzilla.libsdl.org/show_bug.cgi?id=4498
24
25Signed-off-by: Petr Písař <ppisar@redhat.com>
26
27CVE: CVE-2019-7635
28Upstream-Status: Backport
29Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
30
31diff -r a936f9bd3e38 -r f1f5878be5db src/video/SDL_bmp.c
32--- a/src/video/SDL_bmp.c	Mon Jun 10 09:25:05 2019 -0700
33+++ b/src/video/SDL_bmp.c	Tue Jun 11 06:28:12 2019 -0700
34@@ -308,6 +308,12 @@
35 				}
36 				*(bits+i) = (pixel>>shift);
37 				pixel <<= ExpandBMP;
38+				if ( bits[i] >= biClrUsed ) {
39+					SDL_SetError(
40+						"A BMP image contains a pixel with a color out of the palette");
41+					was_error = SDL_TRUE;
42+					goto done;
43+				}
44 			} }
45 			break;
46
47@@ -318,6 +324,16 @@
48 				was_error = SDL_TRUE;
49 				goto done;
50 			}
51+			if ( 8 == biBitCount && palette && biClrUsed < (1 << biBitCount ) ) {
52+				for ( i=0; i<surface->w; ++i ) {
53+					if ( bits[i] >= biClrUsed ) {
54+						SDL_SetError(
55+							"A BMP image contains a pixel with a color out of the palette");
56+						was_error = SDL_TRUE;
57+						goto done;
58+					}
59+				}
60+			}
61 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
62 			/* Byte-swap the pixels if needed. Note that the 24bpp
63 			   case has already been taken care of above. */
64