From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top
Subject: Re: [PATCH 3/7] tap: Check return value of accept4() before calling
 getsockopt()
Date: Thu, 22 Sep 2022 16:30:22 +1000
Message-ID: <YywA/s+sR2uiDTMR@yekko>
In-Reply-To: <20220921205507.2742203-4-sbrivio@redhat.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="===============3110118713409884067=="

--===============3110118713409884067==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit

On Wed, Sep 21, 2022 at 10:55:03PM +0200, Stefano Brivio wrote:
> Reported by Coverity (CWE-119):
> 
> 	Negative value used as argument to a function expecting a
> 	positive value (for example, size of buffer or allocation)
> 
> and harmless, because getsockopt() would return -EBADF if the
> socket is -1, so we wouldn't print anything.
> 
> Check if accept4() returns a valid socket before calling getsockopt()
> on it.
> 
> Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>

Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>

> ---
>  tap.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tap.c b/tap.c
> index 3231da7..4d7422f 100644
> --- a/tap.c
> +++ b/tap.c
> @@ -872,11 +872,13 @@ static void tap_sock_unix_new(struct ctx *c)
>  		int discard = accept4(c->fd_tap_listen, NULL, NULL,
>  				      SOCK_NONBLOCK);
>  
> +		if (discard == -1)
> +			return;
> +
>  		if (!getsockopt(discard, SOL_SOCKET, SO_PEERCRED, &ucred, &len))
>  			info("discarding connection from PID %i", ucred.pid);
>  
> -		if (discard != -1)
> -			close(discard);
> +		close(discard);
>  
>  		return;
>  	}

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

--===============3110118713409884067==
Content-Type: application/pgp-signature
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="signature.asc"
MIME-Version: 1.0
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--===============3110118713409884067==--