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

Message ID 20260706084508.987683-1-h-glibcdev@crystaldown.de (mailing list archive)
State New
Headers
Series [v4.] nss: Use reallocarray to prevent integer overflow in getaddrinfo (bug 33977) |

Checks

Context Check Description
redhat-pt-bot/TryBot-apply_patch success Patch applied to master at the time it was sent
redhat-pt-bot/TryBot-32bit success Build for i686
linaro-tcwg-bot/tcwg_glibc_build--master-arm success Build passed
linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 success Build passed
linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 fail Test failed
linaro-tcwg-bot/tcwg_glibc_check--master-arm success Test passed

Commit Message

Marcus Poller July 6, 2026, 8:37 a.m. UTC
  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(-)
  

Comments

Andreas K. Huettel July 6, 2026, 12:47 p.m. UTC | #1
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;
>
  

Patch

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;