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| author | Michael Niedermayer <michaelni@gmx.at> | 2014-12-16 18:57:54 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2014-12-16 19:19:28 +0100 |
| commit | 93a5a16f136d095d23610f57bdad10ba88120fba (patch) | |
| tree | d1cec22dcb002cc0ced188197dab0a33725e0da1 /libavcodec/xface.h | |
| parent | 3030fb7e0d41836f8add6399e9a7c7b740b48bfd (diff) | |
| download | ffmpeg-93a5a16f136d095d23610f57bdad10ba88120fba.tar.gz | |
avcodec/xface: correct the XFACE_MAX_* values
Fixes out of array access
Fixes: asan_stack-oob_32c12e5_2536_cov_2442316831_lena.xface
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/xface.h')
| -rw-r--r-- | libavcodec/xface.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/libavcodec/xface.h b/libavcodec/xface.h index 63df5d3308..0236d713ad 100644 --- a/libavcodec/xface.h +++ b/libavcodec/xface.h @@ -41,17 +41,17 @@ /* * Image is encoded as a big integer, using characters from '~' to * '!', for a total of 94 symbols. In order to express - * 48x48*2=8*XFACE_MAX_WORDS=4608 - * bits, we need a total of 704 digits, as given by: - * ceil(lg_94(2^4608)) = 704 + * 48x48 pixels with the worst case encoding 666 symbols should + * be sufficient. */ -#define XFACE_MAX_DIGITS 704 +#define XFACE_MAX_DIGITS 666 #define XFACE_BITSPERWORD 8 #define XFACE_WORDCARRY (1 << XFACE_BITSPERWORD) #define XFACE_WORDMASK (XFACE_WORDCARRY - 1) -#define XFACE_MAX_WORDS ((XFACE_PIXELS * 2 + XFACE_BITSPERWORD - 1) / XFACE_BITSPERWORD) +// This must be larger or equal to log256(94^XFACE_MAX_DIGITS) +#define XFACE_MAX_WORDS 546 /* Portable, very large unsigned integer arithmetic is needed. * Implementation uses arrays of WORDs. */ |