[PATCH 11/13] nss_dns: In gaih_getanswer_slice, skip strange aliases (bug 12154)

[Siddhesh Poyarekar]

On 2022-08-10 05:31, Florian Weimer via Libc-alpha wrote:
> If the name is not a host name, skip adding it to the result, instead
> of reporting query failure.  This fixes bug 12154 for getaddrinfo.
> 
> This commit still keeps the old parsing code, and only adjusts when
> a host name is copied.
> ---
>   resolv/nss_dns/dns-host.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)

LGTM.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> 
> diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
> index 0e7eef6889..809a269a7c 100644
> --- a/resolv/nss_dns/dns-host.c
> +++ b/resolv/nss_dns/dns-host.c
> @@ -970,12 +970,12 @@ gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
>   
>   	  n = -1;
>   	}
> -      if (__glibc_unlikely (n < 0 || __libc_res_hnok (buffer) == 0))
> +      if (__glibc_unlikely (n < 0))
>   	{
>   	  ++had_error;
>   	  continue;
>   	}
> -      if (*firstp && canon == NULL)
> +      if (*firstp && canon == NULL && __libc_res_hnok (buffer))
>   	{
>   	  h_name = buffer;
>   	  buffer += h_namelen;
> @@ -1021,14 +1021,14 @@ gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname,
>   
>   	  n = __libc_dn_expand (answer->buf, end_of_message, cp,
>   				tbuf, sizeof tbuf);
> -	  if (__glibc_unlikely (n < 0 || __libc_res_hnok (tbuf) == 0))
> +	  if (__glibc_unlikely (n < 0))
>   	    {
>   	      ++had_error;
>   	      continue;
>   	    }
>   	  cp += n;
>   
> -	  if (*firstp)
> +	  if (*firstp && __libc_res_hnok (tbuf))
>   	    {
>   	      /* Reclaim buffer space.  */
>   	      if (h_name + h_namelen == buffer)