Re: [RFC PATCH 03/15] reftable: don't memset() a NULL from failed malloc()

> Am 03.06.22 um 20:37 schrieb Ævar Arnfjörð Bjarmason:
>> Return NULL instead of possibly feeding a NULL to memset() in
>> reftable_calloc(). This issue was noted by GCC 12's -fanalyzer:
>>
>> 	reftable/publicbasics.c: In function ‘reftable_calloc’:
>> 	reftable/publicbasics.c:43:9: error: use of possibly-NULL ‘p’ where non-null expected [CWE-690] [-Werror=analyzer-possible-null-argument]
>> 	   43 |         memset(p, 0, sz);
>> 	      |         ^~~~~~~~~~~~~~~~
>> 	[...]
>>
>> This bug has been with us ever since this code was added in
>> ef8a6c62687 (reftable: utility functions, 2021-10-07).
>>
>> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>> ---
>>  reftable/publicbasics.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/reftable/publicbasics.c b/reftable/publicbasics.c
>> index 0ad7d5c0ff2..a18167f5ab7 100644
>> --- a/reftable/publicbasics.c
>> +++ b/reftable/publicbasics.c
>> @@ -40,6 +40,8 @@ void reftable_free(void *p)
>>  void *reftable_calloc(size_t sz)
>>  {
>>  	void *p = reftable_malloc(sz);
>> +	if (!p)
>> +		return NULL;
>>  	memset(p, 0, sz);
>>  	return p;
>>  }
>
> We discussed this before, in
> https://lore.kernel.org/git/RFC-patch-2.2-364d1194a95-20220415T101740Z-avarab@gmail.com/
>
> If this code was actually used by Git and still not handling allocation
> failures then I'd propose something like the below instead.
>
> Next I'd probably try to convert reftable_calloc() calls to a variant
> that takes size and count separately -- like calloc(3) does -- to avoid
> unchecked multiplication.
>
> --- >8 ---
> Subject: [PATCH] reftable: remove reftable_set_alloc()