CVE-2017-7592: libtiff: left shift

["Agostino Sarubbo" <ago () gentoo org>]

http://bugzilla.maptools.org/show_bug.cgi?id=2658 :

In tif_getimage.c, in function putagreytile, there is a shift of unsigned char
by 24:
*(pp+1) << 24.

Since there is no cast, *(pp+1) is treated as int, so
UndefinedBehaviorSanitizer says:
runtime error: left shift of 134 by 24 places cannot be represented in type
'int'

Maybe we could have something like:

*cp++ = BWmap[*pp][0] & ((uint32)*(pp+1) << 24 | ~A1);

###########

Fixed per

2017-01-11 Even Rouault <even.rouault at spatialys.com>

        * libtiff/tif_getimage.c: add explicit uint32 cast in putagreytile to
        avoid UndefinedBehaviorSanitizer warning.
        Patch by Nicolás Peña.
        Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2658

--
Agostino Sarubbo
Gentoo Linux Developer