| Brad Bishop | 26bdd44 | 2019-08-16 17:08:17 -0400 | [diff] [blame] | 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 |
| 8 | CVE-2019-7635: Reject BMP images with pixel colors out the palette |
| 9 | If a 1-, 4-, or 8-bit per pixel BMP image declares less used colors |
| 10 | than the palette offers an SDL_Surface with a palette of the indicated |
| 11 | number of used colors is created. If some of the image's pixel |
| 12 | refer to a color number higher then the maximal used colors, a subsequent |
| 13 | bliting 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 |
| 15 | to e.g. an SDL_DisplayFormat() function will result in a buffer overread in |
| 16 | a blit function. |
| 17 | |
| 18 | This patch fixes it by validing each pixel's color to be less than the |
| 19 | maximal color number in the palette. A validation failure raises an |
| 20 | error from a SDL_LoadBMP_RW() function. |
| 21 | |
| 22 | CVE-2019-7635 |
| 23 | https://bugzilla.libsdl.org/show_bug.cgi?id=4498 |
| 24 | |
| 25 | Signed-off-by: Petr Písař <ppisar@redhat.com> |
| 26 | |
| 27 | CVE: CVE-2019-7635 |
| 28 | Upstream-Status: Backport |
| 29 | Signed-off-by: Anuj Mittal <anuj.mittal@intel.com> |
| 30 | |
| 31 | diff -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. */ |