[PATCH v4.] nss: Use reallocarray to prevent integer overflow in getaddrinfo (bug 33977)

[Adhemerval Zanella Netto]

This version looks ok to me.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

On 06/07/26 09:47, Andreas K. Huettel wrote:
> OK for the release with a R-B
> 
> Am Montag, 6. Juli 2026, 17:37:32 Japanische Normalzeit schrieb Marcus Poller:
>> replacing realloc by reallocarray introduces a basic overflow check.
>> (old + count) might still overflow, but since the NSS backend is trusted,
>> we do not consider this to be a valid case.
>> ---
>> v1: https://inbox.sourceware.org/libc-alpha/77a01db3-5619-48b8-9682-85f11cc472bc@crystaldown.de/
>> v2: iterated on Arjuns and Andreas review comments
>> v3: re-submission to support existing tooling
>> v4: moved from reallocarray to __libc_reallocarray due to a regression found by Adhemerval
>> ---
>>  nss/getaddrinfo.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/nss/getaddrinfo.c b/nss/getaddrinfo.c
>> index 4f6ac3358a..45b7f728a1 100644
>> --- a/nss/getaddrinfo.c
>> +++ b/nss/getaddrinfo.c
>> @@ -234,7 +234,7 @@ convert_hostent_to_gaih_addrtuple (const struct addrinfo *req, int family,
>>        array = array->next;
>>      }
>>  
>> -  array = realloc (res->at, (old + count) * sizeof (*array));
>> +  array = __libc_reallocarray (res->at, old + count, sizeof (*array));
>>  
>>    if (array == NULL)
>>      return false;
>>
> 
>