From: Theo Buehler <tb@theobuehler.org>
Subject: Re: bgpd: fix various flowspec parser issues
To: tech@openbsd.org
Date: Mon, 18 May 2026 17:46:54 +0200

On Mon, May 18, 2026 at 01:43:55PM +0200, Claudio Jeker wrote:
> This is a collection of fixes to the flowspec bits in parse.y
> 
> - handle PROTO proto_item like PROTO { proto_item }.
> - extra semicolon after flags
> - The LENGTH spec needs to be adjusted, curflow->type needs to be set
>   before evaluating lengthspec.
> - Twice $$ is used in error checking before $$ was set. Use $1 instead.

ok tb

> 
> 
> -- 
> :wq Claudio
> 
> Index: parse.y
> ===================================================================
> RCS file: /cvs/src/usr.sbin/bgpd/parse.y,v
> diff -u -p -r1.496 parse.y
> --- parse.y	13 May 2026 09:25:11 -0000	1.496
> +++ parse.y	18 May 2026 09:32:46 -0000
> @@ -1221,7 +1221,11 @@ flowspec	: FLOWSPEC af {
>  		}
>  		;
>  
> -proto		: PROTO proto_item
> +proto		: PROTO proto_item {
> +			curflow->type = FLOWSPEC_TYPE_PROTO;
> +			if (push_unary_numop(OP_EQ, $2) == -1)
> +				YYERROR;
> +		}
>  		| PROTO '{' optnl proto_list optnl '}'
>  		;
>  
> @@ -1337,11 +1341,11 @@ flowrule	: from
>  		} flags
>  		| FRAGMENT {
>  			curflow->type = FLOWSPEC_TYPE_FRAG;
> -		} flags;
> +		} flags
>  		| icmpspec
> -		| LENGTH lengthspec {
> +		| LENGTH {
>  			curflow->type = FLOWSPEC_TYPE_PKT_LEN;
> -		}
> +		} lengthspec
>  		| proto
>  		| TOS tos {
>  			curflow->type = FLOWSPEC_TYPE_DSCP;
> @@ -1473,7 +1477,7 @@ tos		: STRING		{
>  			free($1);
>  		}
>  		| NUMBER		{
> -			if ($$ < 0 || $$ > 255) {
> +			if ($1 < 0 || $1 > 255) {
>  				yyerror("illegal tos value %lld", $1);
>  				YYERROR;
>  			}
> @@ -1504,7 +1508,7 @@ length_item	: length			{
>  		;
>  
>  length		: NUMBER			{
> -			if ($$ < 0 || $$ > USHRT_MAX) {
> +			if ($1 < 0 || $1 > USHRT_MAX) {
>  				yyerror("illegal ptk length value %lld", $1);
>  				YYERROR;
>  			}
>