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| author | Alan Coopersmith <alan.coopersmith@oracle.com> | 2015-03-06 22:54:58 -0800 |
|---|---|---|
| committer | Mike DePaulo <mikedep333@gmail.com> | 2015-03-28 13:06:17 -0400 |
| commit | 9f1b041e535c4da6ffbe95a706d46b3bfb5c0321 (patch) | |
| tree | baa77fc555707be4fde1fbbf02dc587d8fdd534f | |
| parent | de7bfbf0e61cdbe5e5c094d8a237cdc87e8b1fc3 (diff) | |
| download | vcxsrv-9f1b041e535c4da6ffbe95a706d46b3bfb5c0321.tar.gz vcxsrv-9f1b041e535c4da6ffbe95a706d46b3bfb5c0321.tar.bz2 vcxsrv-9f1b041e535c4da6ffbe95a706d46b3bfb5c0321.zip | |
bdfReadCharacters: ensure metrics fit into xCharInfo struct [CVE-2015-1804]
We use 32-bit ints to read from the bdf file, but then try to stick
into a 16-bit int in the xCharInfo struct, so make sure they won't
overflow that range.
Found by afl-1.24b.
v2: Verify that additions won't overflow 32-bit int range either.
v3: As Julien correctly observes, the previous check for bh & bw not
being < 0 reduces the number of cases we need to check for overflow.
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>
(cherry picked from commit 2351c83a77a478b49cba6beb2ad386835e264744)
| -rw-r--r-- | libXfont/src/bitmap/bdfread.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/libXfont/src/bitmap/bdfread.c b/libXfont/src/bitmap/bdfread.c index 1b29b81c9..a0ace8f85 100644 --- a/libXfont/src/bitmap/bdfread.c +++ b/libXfont/src/bitmap/bdfread.c @@ -62,8 +62,16 @@ from The Open Group. #if HAVE_STDINT_H #include <stdint.h> -#elif !defined(INT32_MAX) -#define INT32_MAX 0x7fffffff +#else +# ifndef INT32_MAX +# define INT32_MAX 0x7fffffff +# endif +# ifndef INT16_MAX +# define INT16_MAX 0x7fff +# endif +# ifndef INT16_MIN +# define INT16_MIN (0 - 0x8000) +# endif #endif #define INDICES 256 @@ -417,6 +425,12 @@ bdfReadCharacters(FontFilePtr file, FontPtr pFont, bdfFileState *pState, bdfError("DWIDTH y value must be zero\n"); goto BAILOUT; } + /* xCharInfo metrics are stored as INT16 */ + if ((wx < 0) || (wx > INT16_MAX)) { + bdfError("character '%s' has out of range width, %d\n", + charName, wx); + goto BAILOUT; + } line = bdfGetLine(file, lineBuf, BDFLINELEN); if ((!line) || (sscanf((char *) line, "BBX %d %d %d %d", &bw, &bh, &bl, &bb) != 4)) { bdfError("bad 'BBX'\n"); @@ -427,6 +441,14 @@ bdfReadCharacters(FontFilePtr file, FontPtr pFont, bdfFileState *pState, charName, bw, bh); goto BAILOUT; } + /* xCharInfo metrics are read as int, but stored as INT16 */ + if ((bl > INT16_MAX) || (bl < INT16_MIN) || + (bb > INT16_MAX) || (bb < INT16_MIN) || + (bw > (INT16_MAX - bl)) || (bh > (INT16_MAX - bb))) { + bdfError("character '%s' has out of range metrics, %d %d %d %d\n", + charName, bl, (bl+bw), (bh+bb), -bb); + goto BAILOUT; + } line = bdfGetLine(file, lineBuf, BDFLINELEN); if ((line) && (bdfIsPrefix(line, "ATTRIBUTES"))) { for (p = line + strlen("ATTRIBUTES "); |