@matheusbsbs / matheus-bagliano / commits / e6b2582da3

reftable: avoid undefined behaviour breaking t0032

1214aa841bc (reftable: add blocksource, an abstraction for random access reads, 2021-10-07), makes the assumption that it is ok to free a reftable_block pointing to NULL if the size is also set to 0, but implements that using a memset call that at least in glibc based system will trigger a runtime exception if called with a NULL pointer as its first parameter. Avoid doing so by adding a conditional to check for the size in all three identically looking functions that were affected, and therefore, still allow memset to help catch callers that might incorrectly pass a NULL pointer with a non zero size, but avoiding the exception for the valid cases. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Carlo Marcelo Arenas Belón committed Apr 15, 2022 at 01:30 UTC e6b2582da30b599d95f40510777c643b9fba9012

1 file changed +6 -3

reftable/blocksource.c

+6 -3

index 0044eecd9a..db1b7dc966 100644 --- a/reftable/blocksource.c +++ b/reftable/blocksource.c @@ -15,7 +15,8 @@ https://developers.google.com/open-source/licenses/bsd static void strbuf_return_block(void *b, struct reftable_block *dest) { - memset(dest->data, 0xff, dest->len); + if (dest->len) + memset(dest->data, 0xff, dest->len); reftable_free(dest->data); } @@ -56,7 +57,8 @@ void block_source_from_strbuf(struct reftable_block_source *bs, static void malloc_return_block(void *b, struct reftable_block *dest) { - memset(dest->data, 0xff, dest->len); + if (dest->len) + memset(dest->data, 0xff, dest->len); reftable_free(dest->data); } @@ -85,7 +87,8 @@ static uint64_t file_size(void *b) static void file_return_block(void *b, struct reftable_block *dest) { - memset(dest->data, 0xff, dest->len); + if (dest->len) + memset(dest->data, 0xff, dest->len); reftable_free(dest->data); }