# HG changeset patch
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# User Petr Písař <ppisar@redhat.com>
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# Date 1560259692 25200
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# Tue Jun 11 06:28:12 2019 -0700
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# Branch SDL-1.2
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# Node ID f1f5878be5dbf63c1161a8ee52b8a86ece30e552
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# Parent a936f9bd3e381d67d8ddee8b9243f85799ea4798
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CVE-2019-7635: Reject BMP images with pixel colors out the palette
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If a 1-, 4-, or 8-bit per pixel BMP image declares less used colors
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than the palette offers an SDL_Surface with a palette of the indicated
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number of used colors is created. If some of the image's pixel
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refer to a color number higher then the maximal used colors, a subsequent
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bliting operation on the surface will look up a color past a blit map
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(that is based on the palette) memory. I.e. passing such SDL_Surface
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to e.g. an SDL_DisplayFormat() function will result in a buffer overread in
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a blit function.
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This patch fixes it by validing each pixel's color to be less than the
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maximal color number in the palette. A validation failure raises an
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error from a SDL_LoadBMP_RW() function.
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CVE-2019-7635
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https://bugzilla.libsdl.org/show_bug.cgi?id=4498
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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CVE: CVE-2019-7635
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Upstream-Status: Backport
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Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
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diff -r a936f9bd3e38 -r f1f5878be5db src/video/SDL_bmp.c
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--- a/src/video/SDL_bmp.c Mon Jun 10 09:25:05 2019 -0700
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+++ b/src/video/SDL_bmp.c Tue Jun 11 06:28:12 2019 -0700
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@@ -308,6 +308,12 @@
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}
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*(bits+i) = (pixel>>shift);
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pixel <<= ExpandBMP;
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+ if ( bits[i] >= biClrUsed ) {
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+ SDL_SetError(
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+ "A BMP image contains a pixel with a color out of the palette");
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+ was_error = SDL_TRUE;
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+ goto done;
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+ }
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} }
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break;
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@@ -318,6 +324,16 @@
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was_error = SDL_TRUE;
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goto done;
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}
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+ if ( 8 == biBitCount && palette && biClrUsed < (1 << biBitCount ) ) {
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+ for ( i=0; i<surface->w; ++i ) {
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+ if ( bits[i] >= biClrUsed ) {
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+ SDL_SetError(
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+ "A BMP image contains a pixel with a color out of the palette");
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+ was_error = SDL_TRUE;
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+ goto done;
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+ }
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+ }
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+ }
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#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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/* Byte-swap the pixels if needed. Note that the 24bpp
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case has already been taken care of above. */
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