diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-08-16 08:15:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-08-16 11:09:18 +0100 |
| commit | 10f42426e5bcea728d7fae96609b29b4fb1f7518 (patch) | |
| tree | 96616c34b54ec1557e0b65ed307efd6f060141a4 /net | |
| parent | 08e39c0dfa29f233f5a621f7d274b793a080c769 (diff) | |
inet: implement lockless IP_TTL
ip_select_ttl() is racy, because it reads inet->uc_ttl
without proper locking.
Add READ_ONCE()/WRITE_ONCE() annotations while
allowing IP_TTL socket option to be set/read without
holding the socket lock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/ip_output.c | 2 | ||||
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 27 |
2 files changed, 13 insertions, 16 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 8f396eada1b6..ce6257860a40 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -133,7 +133,7 @@ EXPORT_SYMBOL_GPL(ip_local_out); static inline int ip_select_ttl(const struct inet_sock *inet, const struct dst_entry *dst) { - int ttl = inet->uc_ttl; + int ttl = READ_ONCE(inet->uc_ttl); if (ttl < 0) ttl = ip4_dst_hoplimit(dst); diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index cfa65a0b0900..dbb2d2342ebf 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1023,6 +1023,13 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, case IP_BIND_ADDRESS_NO_PORT: inet_assign_bit(BIND_ADDRESS_NO_PORT, sk, val); return 0; + case IP_TTL: + if (optlen < 1) + return -EINVAL; + if (val != -1 && (val < 1 || val > 255)) + return -EINVAL; + WRITE_ONCE(inet->uc_ttl, val); + return 0; } err = 0; @@ -1080,13 +1087,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, case IP_TOS: /* This sets both TOS and Precedence */ __ip_sock_set_tos(sk, val); break; - case IP_TTL: - if (optlen < 1) - goto e_inval; - if (val != -1 && (val < 1 || val > 255)) - goto e_inval; - inet->uc_ttl = val; - break; case IP_MTU_DISCOVER: if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_OMIT) goto e_inval; @@ -1590,6 +1590,11 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname, case IP_BIND_ADDRESS_NO_PORT: val = inet_test_bit(BIND_ADDRESS_NO_PORT, sk); goto copyval; + case IP_TTL: + val = READ_ONCE(inet->uc_ttl); + if (val < 0) + val = READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_default_ttl); + goto copyval; } if (needs_rtnl) @@ -1629,14 +1634,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname, case IP_TOS: val = inet->tos; break; - case IP_TTL: - { - struct net *net = sock_net(sk); - val = (inet->uc_ttl == -1 ? - READ_ONCE(net->ipv4.sysctl_ip_default_ttl) : - inet->uc_ttl); - break; - } case IP_MTU_DISCOVER: val = inet->pmtudisc; break; |