Re: [PATCH v9 18/23] fwd_rule: Fix static checkers warnings in fwd_rule_add()

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, May 06, 2026 at 11:22:36AM +0200, Stefano Brivio wrote:
> The new checks are actually sufficient but not enough for Coverity
> Scan. Now that fwd->sock_count and new->last are affected or supplied
> by clients, we need explicit (albeit redundant) checks on them.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Thanks for the extra details.  I still think this can probably be done
more neatly. but it's good enough for the time being.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  fwd_rule.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/fwd_rule.c b/fwd_rule.c
> index b55e4df..200f4b5 100644
> --- a/fwd_rule.c
> +++ b/fwd_rule.c
> @@ -271,13 +271,24 @@ int fwd_rule_add(struct fwd_table *fwd, const struct fwd_rule *new)
>  		warn("Too many rules (maximum %d)", ARRAY_SIZE(fwd->rules));
>  		return -ENOSPC;
>  	}
> +
>  	if ((fwd->sock_count + num) > ARRAY_SIZE(fwd->socks)) {
>  		warn("Rules require too many listening sockets (maximum %d)",
>  		     ARRAY_SIZE(fwd->socks));
>  		return -ENOSPC;
>  	}
> +	/* Redundant (see check just above), to make static checkers happy */
> +	if (fwd->sock_count > ARRAY_SIZE(fwd->socks))
> +		return -ENOSPC;
>  
>  	fwd->rulesocks[fwd->count] = &fwd->socks[fwd->sock_count];
> +
> +	/* Redundant, but not for static checkers, that might be missing that
> +	 * due to the check on 'num' above against ARRAY_SIZE(fwd->socks), we
> +	 * have a proper upper bound for new->last in the loop below.
> +	 */
> +	if (new->last > ARRAY_SIZE(fwd->socks) + new->first)
> +		return -ENOSPC;
>  	for (port = new->first; port <= new->last; port++)
>  		fwd->rulesocks[fwd->count][port - new->first] = -1;
>  
> -- 
> 2.43.0
> 

-- 
David Gibson (he or they)	| 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

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