On Sun, 11 Aug 2013 03:21:39 +0200 Roland Mainz wrote:
> I'm currently experimenting with clang's "integer sanitiser" option
> ("-fsanitize=integer" , see
> http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation)
> with ast-ksh.2013-08-07 on a SuSE 12.3/AMD64/64bit build created
> with...
> -- snip --
> $ (export CC='/usr/bin/clang -std=gnu1x -fsanitize=integer -g
> -fno-omit-frame-pointer -fno-optimize-sibling-calls -Wno-parentheses
> -Wno-logical-op-parentheses' LD="$CC" CCFLAGS="-g"; ksh ./bin/package
> make PACKAGE_OPTIONS='map-libc' CC="$CC" CCFLAGS="$CCFLAGS" 2>&1 | tee
> -a buildlog.log)
> -- snip --
> ... during testing I found the following integer overflow issues which
> _may_ be portability issues:
> -- snip --
> $ ksh -c 'x="a1a" ; [[ $x == ~(E)([[:alpha:]]|[[:digit:]])+ ]]'
> src/lib/libast/aso/asothreadid.c:48:14: runtime error: unsigned
> integer overflow: 530404196 * 17109811 cannot be represented in type
> 'unsigned int'
> src/lib/libast/cdt/dtstrhash.c:43:20: runtime error: unsigned integer
> overflow: 2166136238 * 16777619 cannot be represented in type
> 'unsigned int'
> src/lib/libast/regex/regnexec.c:258:80: runtime error: unsigned
> integer overflow: 18446744073709551615 * 16 cannot be represented in
> type 'unsigned long'
> src/lib/libast/regex/regnexec.c:258:68: runtime error: unsigned
> integer overflow: 32 + 18446744073709551600 cannot be represented in
> type 'unsigned long'
> -- snip --
> (the hits in src/lib/libast/aso/asothreadid.c and
> src/lib/libast/cdt/dtstrhash.c happen at shell startup ; |unsigned
> long| is an |uint64_t| for 64bit builds)
> Erm... Glenn and Michal... what do you think ?
without looking at the code the first 2 are PRNG related
which explicitly expect and allow for integer overflow and
mask off the required bits
the last 2 are allocation related
stkpush(env->mst, sizeof(Match_frame_t) + (num - 1) *
sizeof(regmatch_t)))
and involve C?? unsigned escalation rules
looks like (num - 1) escalates to unsigned
in this case num==0 which makes it a large unsigned int
does anyone know how to cast this to the equivalent
int a = sizeof(Match_frame_t);
int b = sizeof(regmatch_t);
a + (num - 1) * b;
is it
sizeof(Match_frame_t) + (num - 1) * (int)sizeof(regmatch_t)
or
(int)sizeof(Match_frame_t) + (num - 1) * (int)sizeof(regmatch_t)
or something worse
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