From 33372f2b6c6d4407561d1a7a093c127db55e945b Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Tue, 23 Aug 2022 10:46:44 -0700 Subject: [PATCH] net: Fix data-races around sysctl_[rw]mem_(max|default). [ Upstream commit 1227c1771dd2ad44318aa3ab9e3a293b3f34ff2a ] While reading sysctl_[rw]mem_(max|default), they can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/filter.c | 4 ++-- net/core/sock.c | 8 ++++---- net/ipv4/ip_output.c | 2 +- net/ipv4/tcp_output.c | 2 +- net/netfilter/ipvs/ip_vs_sync.c | 4 ++-- 5 files changed, 10 insertions(+), 10 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index ac64395..2da00f6 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4744,14 +4744,14 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, /* Only some socketops are supported */ switch (optname) { case SO_RCVBUF: - val = min_t(u32, val, sysctl_rmem_max); + val = min_t(u32, val, READ_ONCE(sysctl_rmem_max)); val = min_t(int, val, INT_MAX / 2); sk->sk_userlocks |= SOCK_RCVBUF_LOCK; WRITE_ONCE(sk->sk_rcvbuf, max_t(int, val * 2, SOCK_MIN_RCVBUF)); break; case SO_SNDBUF: - val = min_t(u32, val, sysctl_wmem_max); + val = min_t(u32, val, READ_ONCE(sysctl_wmem_max)); val = min_t(int, val, INT_MAX / 2); sk->sk_userlocks |= SOCK_SNDBUF_LOCK; WRITE_ONCE(sk->sk_sndbuf, diff --git a/net/core/sock.c b/net/core/sock.c index deaed1b..62fd486 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1014,7 +1014,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname, * play 'guess the biggest size' games. RCVBUF/SNDBUF * are treated in BSD as hints */ - val = min_t(u32, val, sysctl_wmem_max); + val = min_t(u32, val, READ_ONCE(sysctl_wmem_max)); set_sndbuf: /* Ensure val * 2 fits into an int, to prevent max_t() * from treating it as a negative value. @@ -1046,7 +1046,7 @@ set_sndbuf: * play 'guess the biggest size' games. RCVBUF/SNDBUF * are treated in BSD as hints */ - __sock_set_rcvbuf(sk, min_t(u32, val, sysctl_rmem_max)); + __sock_set_rcvbuf(sk, min_t(u32, val, READ_ONCE(sysctl_rmem_max))); break; case SO_RCVBUFFORCE: @@ -3124,8 +3124,8 @@ void sock_init_data(struct socket *sock, struct sock *sk) timer_setup(&sk->sk_timer, NULL, 0); sk->sk_allocation = GFP_KERNEL; - sk->sk_rcvbuf = sysctl_rmem_default; - sk->sk_sndbuf = sysctl_wmem_default; + sk->sk_rcvbuf = READ_ONCE(sysctl_rmem_default); + sk->sk_sndbuf = READ_ONCE(sysctl_wmem_default); sk->sk_state = TCP_CLOSE; sk_set_socket(sk, sock); diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 131066d..7aff017 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1712,7 +1712,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, sk->sk_protocol = ip_hdr(skb)->protocol; sk->sk_bound_dev_if = arg->bound_dev_if; - sk->sk_sndbuf = sysctl_wmem_default; + sk->sk_sndbuf = READ_ONCE(sysctl_wmem_default); ipc.sockc.mark = fl4.flowi4_mark; err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0, &ipc, &rt, MSG_DONTWAIT); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 40c9da4..ed2e183 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -239,7 +239,7 @@ void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss, if (wscale_ok) { /* Set window scaling on max possible window */ space = max_t(u32, space, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); - space = max_t(u32, space, sysctl_rmem_max); + space = max_t(u32, space, READ_ONCE(sysctl_rmem_max)); space = min_t(u32, space, *window_clamp); *rcv_wscale = clamp_t(int, ilog2(space) - 15, 0, TCP_MAX_WSCALE); diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c index 9d43277..a56fd0b 100644 --- a/net/netfilter/ipvs/ip_vs_sync.c +++ b/net/netfilter/ipvs/ip_vs_sync.c @@ -1280,12 +1280,12 @@ static void set_sock_size(struct sock *sk, int mode, int val) lock_sock(sk); if (mode) { val = clamp_t(int, val, (SOCK_MIN_SNDBUF + 1) / 2, - sysctl_wmem_max); + READ_ONCE(sysctl_wmem_max)); sk->sk_sndbuf = val * 2; sk->sk_userlocks |= SOCK_SNDBUF_LOCK; } else { val = clamp_t(int, val, (SOCK_MIN_RCVBUF + 1) / 2, - sysctl_rmem_max); + READ_ONCE(sysctl_rmem_max)); sk->sk_rcvbuf = val * 2; sk->sk_userlocks |= SOCK_RCVBUF_LOCK; } -- 2.7.4