From 7de6d09f51917c829af2b835aba8bb5040f8e86a Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Tue, 23 Aug 2022 10:46:49 -0700 Subject: [PATCH] net: Fix data-races around sysctl_optmem_max. While reading sysctl_optmem_max, it 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 --- net/core/bpf_sk_storage.c | 5 +++-- net/core/filter.c | 9 +++++---- net/core/sock.c | 8 +++++--- net/ipv4/ip_sockglue.c | 6 +++--- net/ipv6/ipv6_sockglue.c | 4 ++-- 5 files changed, 18 insertions(+), 14 deletions(-) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 1b7f385..94374d5 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -310,11 +310,12 @@ BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk) static int bpf_sk_storage_charge(struct bpf_local_storage_map *smap, void *owner, u32 size) { + int optmem_max = READ_ONCE(sysctl_optmem_max); struct sock *sk = (struct sock *)owner; /* same check as in sock_kmalloc() */ - if (size <= sysctl_optmem_max && - atomic_read(&sk->sk_omem_alloc) + size < sysctl_optmem_max) { + if (size <= optmem_max && + atomic_read(&sk->sk_omem_alloc) + size < optmem_max) { atomic_add(size, &sk->sk_omem_alloc); return 0; } diff --git a/net/core/filter.c b/net/core/filter.c index c4f14ad..c191db8 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1214,10 +1214,11 @@ void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) static bool __sk_filter_charge(struct sock *sk, struct sk_filter *fp) { u32 filter_size = bpf_prog_size(fp->prog->len); + int optmem_max = READ_ONCE(sysctl_optmem_max); /* same check as in sock_kmalloc() */ - if (filter_size <= sysctl_optmem_max && - atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) { + if (filter_size <= optmem_max && + atomic_read(&sk->sk_omem_alloc) + filter_size < optmem_max) { atomic_add(filter_size, &sk->sk_omem_alloc); return true; } @@ -1548,7 +1549,7 @@ int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk) if (IS_ERR(prog)) return PTR_ERR(prog); - if (bpf_prog_size(prog->len) > sysctl_optmem_max) + if (bpf_prog_size(prog->len) > READ_ONCE(sysctl_optmem_max)) err = -ENOMEM; else err = reuseport_attach_prog(sk, prog); @@ -1615,7 +1616,7 @@ int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk) } } else { /* BPF_PROG_TYPE_SOCKET_FILTER */ - if (bpf_prog_size(prog->len) > sysctl_optmem_max) { + if (bpf_prog_size(prog->len) > READ_ONCE(sysctl_optmem_max)) { err = -ENOMEM; goto err_prog_put; } diff --git a/net/core/sock.c b/net/core/sock.c index 303af52..95abf46 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2536,7 +2536,7 @@ struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size, /* small safe race: SKB_TRUESIZE may differ from final skb->truesize */ if (atomic_read(&sk->sk_omem_alloc) + SKB_TRUESIZE(size) > - sysctl_optmem_max) + READ_ONCE(sysctl_optmem_max)) return NULL; skb = alloc_skb(size, priority); @@ -2554,8 +2554,10 @@ struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size, */ void *sock_kmalloc(struct sock *sk, int size, gfp_t priority) { - if ((unsigned int)size <= sysctl_optmem_max && - atomic_read(&sk->sk_omem_alloc) + size < sysctl_optmem_max) { + int optmem_max = READ_ONCE(sysctl_optmem_max); + + if ((unsigned int)size <= optmem_max && + atomic_read(&sk->sk_omem_alloc) + size < optmem_max) { void *mem; /* First do the add, to avoid the race if kmalloc * might sleep. diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index a8a323e..e49a61a 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -772,7 +772,7 @@ static int ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval, int optlen) if (optlen < GROUP_FILTER_SIZE(0)) return -EINVAL; - if (optlen > sysctl_optmem_max) + if (optlen > READ_ONCE(sysctl_optmem_max)) return -ENOBUFS; gsf = memdup_sockptr(optval, optlen); @@ -808,7 +808,7 @@ static int compat_ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval, if (optlen < size0) return -EINVAL; - if (optlen > sysctl_optmem_max - 4) + if (optlen > READ_ONCE(sysctl_optmem_max) - 4) return -ENOBUFS; p = kmalloc(optlen + 4, GFP_KERNEL); @@ -1233,7 +1233,7 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, if (optlen < IP_MSFILTER_SIZE(0)) goto e_inval; - if (optlen > sysctl_optmem_max) { + if (optlen > READ_ONCE(sysctl_optmem_max)) { err = -ENOBUFS; break; } diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 222f6bf..e0dcc7a 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -210,7 +210,7 @@ static int ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval, if (optlen < GROUP_FILTER_SIZE(0)) return -EINVAL; - if (optlen > sysctl_optmem_max) + if (optlen > READ_ONCE(sysctl_optmem_max)) return -ENOBUFS; gsf = memdup_sockptr(optval, optlen); @@ -244,7 +244,7 @@ static int compat_ipv6_set_mcast_msfilter(struct sock *sk, sockptr_t optval, if (optlen < size0) return -EINVAL; - if (optlen > sysctl_optmem_max - 4) + if (optlen > READ_ONCE(sysctl_optmem_max) - 4) return -ENOBUFS; p = kmalloc(optlen + 4, GFP_KERNEL); -- 2.7.4