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From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>,
	leonardo.macchia@gmail.com
Subject: Re: [PATCH 1/3] inet: Fix getnameinfo (NI_NOFQDN) race condition (BZ#28566)
Date: Thu, 11 Nov 2021 09:16:31 +0100	[thread overview]
Message-ID: <87r1bn150g.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <20211110185832.1931688-2-adhemerval.zanella@linaro.org> (Adhemerval Zanella via Libc-alpha's message of "Wed, 10 Nov 2021 15:58:30 -0300")

* Adhemerval Zanella via Libc-alpha:

> diff --git a/inet/getnameinfo.c b/inet/getnameinfo.c
> index 8380d85783..58ebbb1154 100644
> --- a/inet/getnameinfo.c
> +++ b/inet/getnameinfo.c
> @@ -86,55 +86,75 @@ libc_freeres_ptr (static char *domain);
>  static char *
>  nrl_domainname (void)
>  {
> +  __libc_lock_define_initialized (static, lock);
> +  __libc_lock_lock (lock);
>  
> +  static bool not_first = false;
>    if (! not_first)

> +    done:
> +      scratch_buffer_free (&tmpbuf);
> +      not_first = true;

This is missing the acquire/release pairing for the double-checked
locking idiom.  You can probably use the domain variable directly.

> -	      if ((c = strchr (tmpbuf.data, '.')))
> +	      if (h && (c = strchr(h->h_name, '.')))

h != NULL?

> +		      if (!scratch_buffer_grow_preserve (&tmpbuf))


I think the change to _preserve should be in the alloca elimination
patch (but see my comment there).

Thanks,
Florian


  reply	other threads:[~2021-11-11  8:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-10 18:58 [PATCH 0/3] Fixes for getnameinfo() with NI_NOFQDN Adhemerval Zanella
2021-11-10 18:58 ` [PATCH 1/3] inet: Fix getnameinfo (NI_NOFQDN) race condition (BZ#28566) Adhemerval Zanella
2021-11-11  8:16   ` Florian Weimer [this message]
2021-11-11 13:34     ` Adhemerval Zanella
2021-11-11 13:54       ` Florian Weimer
2021-11-11 14:09         ` Adhemerval Zanella
2021-11-11 14:12           ` Florian Weimer
2021-11-11 14:17             ` Adhemerval Zanella
2021-11-11 17:41               ` Florian Weimer
2021-11-10 18:58 ` [PATCH 2/3] inet: Remove strdupa from nrl_domainname() Adhemerval Zanella
2021-11-11  8:18   ` Florian Weimer
2021-11-11 13:36     ` Adhemerval Zanella
2021-11-11 14:00       ` Florian Weimer
2021-11-10 18:58 ` [PATCH 3/3] inet: Return EAI_MEMORY when nrl_domainname() fails to allocate memory Adhemerval Zanella

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