[PATCH] wrapper: avoid UB in macOS
- From
Carlo Marcelo Arenas Belón <carenas@gmail.com>
- Date
- Jun 16, 2019, 18:40 UTC
- Message-ID
- <20190616184003.17236-1-carenas@gmail.com>
0620b39b3b ("compat: add a mkstemps() compatibility function", 2009-05-31) included a function based on code from libiberty which would result in undefined behaviour in platforms where timeval's tv_usec is a 32-bit signed type as shown by:
wrapper.c:505:31: runtime error: left shift of 594546 by 16 places cannot be represented in type '__darwin_suseconds_t' (aka 'int')
interestingly the version of this code from gcc never had this bug and the code had a cast that would had prevented the issue (at least in 64-bit platforms) but was misapplied.
change the cast to uint64_t so it also works in 32-bit platforms.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> --- wrapper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/wrapper.c b/wrapper.c index ea3cf64d4c..1e45ab7b92 100644 --- a/wrapper.c +++ b/wrapper.c @@ -502,7 +502,7 @@ int git_mkstemps_mode(char *pattern, int suffix_len, int mode) * Try TMP_MAX different filenames. */ gettimeofday(&tv, NULL); - value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid(); + value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid(); filename_template = &pattern[len - 6 - suffix_len]; for (count = 0; count < TMP_MAX; ++count) { uint64_t v = value;
-- 2.22.0