Commit 1bc46dd2 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv6: pass proto by value to ipv6_push_nfrag_opts() and ipv6_push_frag_opts() 



With CONFIG_STACKPROTECTOR_STRONG=y, it is better to avoid passing
a pointer to an automatic variable.

Change these exported functions to return 'u8 proto'
instead of void.

- ipv6_push_nfrag_opts()
- ipv6_push_frag_opts()

For instance, replace
	ipv6_push_frag_opts(skb, opt, &proto);
with:
	proto = ipv6_push_frag_opts(skb, opt, proto);

Note that even after this change, ip6_xmit() has to use a stack canary
because of @first_hop variable.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260130210303.3888261-2-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e0221553

include/net/ipv6.h

+5 −5
Original line number Diff line number Diff line
@@ -1151,11 +1151,11 @@ int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb); 
 *	Extension header (options) processing

 */



void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

			  u8 *proto, struct in6_addr **daddr_p,

u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

			u8 proto, struct in6_addr **daddr_p,

			struct in6_addr *saddr);

void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

			 u8 *proto);

u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

		       u8 proto);



int ipv6_skip_exthdr(const struct sk_buff *, int start, u8 *nexthdrp,

		     __be16 *frag_offp);

net/ipv6/exthdrs.c

+29 −26
Original line number Diff line number Diff line
@@ -1074,7 +1074,7 @@ int ipv6_parse_hopopts(struct sk_buff *skb) 
 *	for headers.

 */



static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,

static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto,

			   struct ipv6_rt_hdr *opt,

			   struct in6_addr **addr_p, struct in6_addr *saddr)

{
@@ -1095,11 +1095,11 @@ static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 
	phdr->addr[hops - 1] = **addr_p;

	*addr_p = ihdr->addr;



	phdr->rt_hdr.nexthdr = *proto;

	*proto = NEXTHDR_ROUTING;

	phdr->rt_hdr.nexthdr = proto;

	return NEXTHDR_ROUTING;

}



static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,

static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto,

			   struct ipv6_rt_hdr *opt,

			   struct in6_addr **addr_p, struct in6_addr *saddr)

{
@@ -1144,11 +1144,11 @@ static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 
	}

#endif



	sr_phdr->nexthdr = *proto;

	*proto = NEXTHDR_ROUTING;

	sr_phdr->nexthdr = proto;

	return NEXTHDR_ROUTING;

}



static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,

static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto,

			  struct ipv6_rt_hdr *opt,

			  struct in6_addr **addr_p, struct in6_addr *saddr)

{
@@ -1156,46 +1156,49 @@ static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 
	case IPV6_SRCRT_TYPE_0:

	case IPV6_SRCRT_STRICT:

	case IPV6_SRCRT_TYPE_2:

		ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);

		proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);

		break;

	case IPV6_SRCRT_TYPE_4:

		ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);

		proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);

		break;

	default:

		break;

	}

	return proto;

}



static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)

static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt)

{

	struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));



	memcpy(h, opt, ipv6_optlen(opt));

	h->nexthdr = *proto;

	*proto = type;

	h->nexthdr = proto;

	return type;

}



void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

			  u8 *proto,

u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,

			u8 proto,

			struct in6_addr **daddr, struct in6_addr *saddr)

{

	if (opt->srcrt) {

		ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);

		proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);

		/*

		 * IPV6_RTHDRDSTOPTS is ignored

		 * unless IPV6_RTHDR is set (RFC3542).

		 */

		if (opt->dst0opt)

			ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);

			proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);

	}

	if (opt->hopopt)

		ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);

		proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);

	return proto;

}



void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)

u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto)

{

	if (opt->dst1opt)

		ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);

		proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);

	return proto;

}

EXPORT_SYMBOL(ipv6_push_frag_opts);

net/ipv6/ip6_output.c

+11 −8
Original line number Diff line number Diff line
@@ -305,10 +305,11 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, 
		seg_len += opt->opt_nflen + opt->opt_flen;



		if (opt->opt_flen)

			ipv6_push_frag_opts(skb, opt, &proto);

			proto = ipv6_push_frag_opts(skb, opt, proto);



		if (opt->opt_nflen)

			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop,

			proto = ipv6_push_nfrag_opts(skb, opt, proto,

						     &first_hop,

						     &fl6->saddr);

	}
@@ -1940,11 +1941,13 @@ struct sk_buff *__ip6_make_skb(struct sock *sk, 
	__skb_pull(skb, skb_network_header_len(skb));



	final_dst = &fl6->daddr;

	if (opt && opt->opt_flen)

		ipv6_push_frag_opts(skb, opt, &proto);

	if (opt && opt->opt_nflen)

		ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst, &fl6->saddr);



	if (opt) {

		if (opt->opt_flen)

			proto = ipv6_push_frag_opts(skb, opt, proto);

		if (opt->opt_nflen)

			proto = ipv6_push_nfrag_opts(skb, opt, proto,

						     &final_dst, &fl6->saddr);

	}

	skb_push(skb, sizeof(struct ipv6hdr));

	skb_reset_network_header(skb);

	hdr = ipv6_hdr(skb);

net/ipv6/ip6_tunnel.c

+1 −1
Original line number Diff line number Diff line
@@ -1265,7 +1265,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield, 


	if (encap_limit >= 0) {

		init_tel_txopt(&opt, encap_limit);

		ipv6_push_frag_opts(skb, &opt.ops, &proto);

		proto = ipv6_push_frag_opts(skb, &opt.ops, proto);

	}



	skb_push(skb, sizeof(struct ipv6hdr));