Commit 0f95f7d4 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
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bpf: net: Avoid do_ipv6_getsockopt() taking sk lock when called from bpf 



Similar to the earlier patch that changes sk_getsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking the
lock when called from bpf.  This patch also changes do_ipv6_getsockopt()
to use sockopt_{lock,release}_sock() such that bpf_getsockopt(SOL_IPV6)
can reuse do_ipv6_getsockopt().

Although bpf_getsockopt(SOL_IPV6) currently does not support optname
that requires lock_sock(), using sockopt_{lock,release}_sock()
consistently across *_getsockopt() will make future optname addition
harder to miss the sockopt_{lock,release}_sock() usage. eg. when
adding new optname that requires a lock and the new optname is
needed in bpf_getsockopt() also.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002859.2893064-1-kafai@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6dadbe4b

net/ipv6/ipv6_sockglue.c

+8 −8
Original line number Diff line number Diff line
@@ -1078,7 +1078,7 @@ static int ipv6_get_msfilter(struct sock *sk, sockptr_t optval, 
	if (gsf.gf_group.ss_family != AF_INET6)

		return -EADDRNOTAVAIL;

	num = gsf.gf_numsrc;

	lock_sock(sk);

	sockopt_lock_sock(sk);

	err = ip6_mc_msfget(sk, &gsf, optval, size0);

	if (!err) {

		if (num > gsf.gf_numsrc)
@@ -1088,7 +1088,7 @@ static int ipv6_get_msfilter(struct sock *sk, sockptr_t optval, 
		    copy_to_sockptr(optval, &gsf, size0))

			err = -EFAULT;

	}

	release_sock(sk);

	sockopt_release_sock(sk);

	return err;

}
@@ -1114,9 +1114,9 @@ static int compat_ipv6_get_msfilter(struct sock *sk, sockptr_t optval, 
	if (gf.gf_group.ss_family != AF_INET6)

		return -EADDRNOTAVAIL;



	lock_sock(sk);

	sockopt_lock_sock(sk);

	err = ip6_mc_msfget(sk, &gf, optval, size0);

	release_sock(sk);

	sockopt_release_sock(sk);

	if (err)

		return err;

	if (num > gf.gf_numsrc)
@@ -1175,11 +1175,11 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname, 
		msg.msg_controllen = len;

		msg.msg_flags = 0;



		lock_sock(sk);

		sockopt_lock_sock(sk);

		skb = np->pktoptions;

		if (skb)

			ip6_datagram_recv_ctl(sk, &msg, skb);

		release_sock(sk);

		sockopt_release_sock(sk);

		if (!skb) {

			if (np->rxopt.bits.rxinfo) {

				struct in6_pktinfo src_info;
@@ -1268,11 +1268,11 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname, 
	{

		struct ipv6_txoptions *opt;



		lock_sock(sk);

		sockopt_lock_sock(sk);

		opt = rcu_dereference_protected(np->opt,

						lockdep_sock_is_held(sk));

		len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len);

		release_sock(sk);

		sockopt_release_sock(sk);

		/* check if ipv6_getsockopt_sticky() returns err code */

		if (len < 0)

			return len;