|
 |
7c7644a |
From beef32b0e510371f3c968d22a1e3d48abbf366c6 Mon Sep 17 00:00:00 2001
|
|
|
7c7644a |
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
|
|
|
7c7644a |
Date: Tue, 19 Feb 2019 14:52:52 +0100
|
|
|
7c7644a |
Subject: [PATCH] CVE-2019-7635: Reject BMP images with pixel colors out the
|
|
|
7c7644a |
palette
|
|
|
7c7644a |
MIME-Version: 1.0
|
|
|
7c7644a |
Content-Type: text/plain; charset=UTF-8
|
|
|
7c7644a |
Content-Transfer-Encoding: 8bit
|
|
|
7c7644a |
|
|
|
7c7644a |
If a 1-, 4-, or 8-bit per pixel BMP image declares less used colors
|
|
|
7c7644a |
than the palette offers an SDL_Surface with a palette of the indicated
|
|
|
7c7644a |
number of used colors is created. If some of the image's pixel
|
|
|
7c7644a |
refer to a color number higher then the maximal used colors, a subsequent
|
|
|
7c7644a |
bliting operation on the surface will look up a color past a blit map
|
|
|
7c7644a |
(that is based on the palette) memory. I.e. passing such SDL_Surface
|
|
|
7c7644a |
to e.g. an SDL_DisplayFormat() function will result in a buffer overread in
|
|
|
7c7644a |
a blit function.
|
|
|
7c7644a |
|
|
|
7c7644a |
This patch fixes it by validing each pixel's color to be less than the
|
|
|
7c7644a |
maximal color number in the palette. A validation failure raises an
|
|
|
7c7644a |
error from a SDL_LoadBMP_RW() function.
|
|
|
7c7644a |
|
|
|
7c7644a |
CVE-2019-7635
|
|
|
7c7644a |
https://bugzilla.libsdl.org/show_bug.cgi?id=4498
|
|
|
7c7644a |
|
|
|
7c7644a |
Signed-off-by: Petr Písař <ppisar@redhat.com>
|
|
|
7c7644a |
---
|
|
|
7c7644a |
src/video/SDL_bmp.c | 16 ++++++++++++++++
|
|
|
7c7644a |
1 file changed, 16 insertions(+)
|
|
|
7c7644a |
|
|
|
7c7644a |
diff --git a/src/video/SDL_bmp.c b/src/video/SDL_bmp.c
|
|
|
7c7644a |
index 3accded..8eadc5f 100644
|
|
|
7c7644a |
--- a/src/video/SDL_bmp.c
|
|
|
7c7644a |
+++ b/src/video/SDL_bmp.c
|
|
|
7c7644a |
@@ -300,6 +300,12 @@ SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
|
|
|
7c7644a |
}
|
|
|
7c7644a |
*(bits+i) = (pixel>>shift);
|
|
|
7c7644a |
pixel <<= ExpandBMP;
|
|
|
7c7644a |
+ if ( bits[i] >= biClrUsed ) {
|
|
|
7c7644a |
+ SDL_SetError(
|
|
|
7c7644a |
+ "A BMP image contains a pixel with a color out of the palette");
|
|
|
7c7644a |
+ was_error = SDL_TRUE;
|
|
|
7c7644a |
+ goto done;
|
|
|
7c7644a |
+ }
|
|
|
7c7644a |
} }
|
|
|
7c7644a |
break;
|
|
|
7c7644a |
|
|
|
7c7644a |
@@ -310,6 +316,16 @@ SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
|
|
|
7c7644a |
was_error = SDL_TRUE;
|
|
|
7c7644a |
goto done;
|
|
|
7c7644a |
}
|
|
|
7c7644a |
+ if ( 8 == biBitCount && palette && biClrUsed < (1 << biBitCount ) ) {
|
|
|
7c7644a |
+ for ( i=0; i<surface->w; ++i ) {
|
|
|
7c7644a |
+ if ( bits[i] >= biClrUsed ) {
|
|
|
7c7644a |
+ SDL_SetError(
|
|
|
7c7644a |
+ "A BMP image contains a pixel with a color out of the palette");
|
|
|
7c7644a |
+ was_error = SDL_TRUE;
|
|
|
7c7644a |
+ goto done;
|
|
|
7c7644a |
+ }
|
|
|
7c7644a |
+ }
|
|
|
7c7644a |
+ }
|
|
|
7c7644a |
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
|
|
|
7c7644a |
/* Byte-swap the pixels if needed. Note that the 24bpp
|
|
|
7c7644a |
case has already been taken care of above. */
|
|
|
7c7644a |
--
|
|
|
7c7644a |
2.20.1
|
|
|
7c7644a |
|