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| author | Eric Dumazet <edumazet@google.com> | 2023-09-18 14:23:21 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2023-09-19 18:21:44 +0200 |
| commit | fa17a6d8a5bd0cd7565b613cb804242cd0f6b7ab (patch) | |
| tree | 47b212f49ee830235b382165cf734328cdff2e00 /net | |
| parent | 6a23c555f7eb436d6799533675ffa179db3d5834 (diff) | |
| download | lwn-fa17a6d8a5bd0cd7565b613cb804242cd0f6b7ab.tar.gz lwn-fa17a6d8a5bd0cd7565b613cb804242cd0f6b7ab.zip | |
ipv6: lockless IPV6_ADDR_PREFERENCES implementation
We have data-races while reading np->srcprefs
Switch the field to a plain byte, add READ_ONCE()
and WRITE_ONCE() annotations where needed,
and IPV6_ADDR_PREFERENCES setsockopt() can now be lockless.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230918142321.1794107-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/ip6_output.c | 2 | ||||
| -rw-r--r-- | net/ipv6/ipv6_sockglue.c | 19 | ||||
| -rw-r--r-- | net/ipv6/route.c | 2 |
3 files changed, 12 insertions, 11 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 7e5d9eeb990f..951ba8089b5b 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1113,7 +1113,7 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, rcu_read_lock(); from = rt ? rcu_dereference(rt->from) : NULL; err = ip6_route_get_saddr(net, from, &fl6->daddr, - sk ? inet6_sk(sk)->srcprefs : 0, + sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0, &fl6->saddr); rcu_read_unlock(); diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index e9dc6f881bb9..7d661735cb9d 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -505,6 +505,10 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname, return -EINVAL; inet6_assign_bit(SNDFLOW, sk, valbool); return 0; + case IPV6_ADDR_PREFERENCES: + if (optlen < sizeof(int)) + return -EINVAL; + return ip6_sock_set_addr_preferences(sk, val); } if (needs_rtnl) rtnl_lock(); @@ -964,11 +968,6 @@ done: retv = xfrm_user_policy(sk, optname, optval, optlen); break; - case IPV6_ADDR_PREFERENCES: - if (optlen < sizeof(int)) - goto e_inval; - retv = __ip6_sock_set_addr_preferences(sk, val); - break; case IPV6_RECVFRAGSIZE: np->rxopt.bits.recvfragsize = valbool; retv = 0; @@ -1415,23 +1414,25 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname, } case IPV6_ADDR_PREFERENCES: + { + u8 srcprefs = READ_ONCE(np->srcprefs); val = 0; - if (np->srcprefs & IPV6_PREFER_SRC_TMP) + if (srcprefs & IPV6_PREFER_SRC_TMP) val |= IPV6_PREFER_SRC_TMP; - else if (np->srcprefs & IPV6_PREFER_SRC_PUBLIC) + else if (srcprefs & IPV6_PREFER_SRC_PUBLIC) val |= IPV6_PREFER_SRC_PUBLIC; else { /* XXX: should we return system default? */ val |= IPV6_PREFER_SRC_PUBTMP_DEFAULT; } - if (np->srcprefs & IPV6_PREFER_SRC_COA) + if (srcprefs & IPV6_PREFER_SRC_COA) val |= IPV6_PREFER_SRC_COA; else val |= IPV6_PREFER_SRC_HOME; break; - + } case IPV6_MINHOPCOUNT: val = READ_ONCE(np->min_hopcount); break; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 9d8dfc7423e4..b132feae3393 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2622,7 +2622,7 @@ static struct dst_entry *ip6_route_output_flags_noref(struct net *net, if (!any_src) flags |= RT6_LOOKUP_F_HAS_SADDR; else if (sk) - flags |= rt6_srcprefs2flags(inet6_sk(sk)->srcprefs); + flags |= rt6_srcprefs2flags(READ_ONCE(inet6_sk(sk)->srcprefs)); return fib6_rule_lookup(net, fl6, NULL, flags, ip6_pol_route_output); } |