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 <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 1b7f385..94374d5 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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);