From: Eric Dumazet edumazet@google.com
mainline inclusion from mainline-v5.12-rc1-dontuse commit 3d368ab87cf6681f928de1ddf804d69600671bb2 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9GZAQ CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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It is simpler to make net->net_cookie a plain u64 written once in setup_net() instead of looping and using atomic64 helpers.
Lorenz Bauer wants to add SO_NETNS_COOKIE socket option and this patch would makes his patch series simpler.
Signed-off-by: Eric Dumazet edumazet@google.com Cc: Daniel Borkmann daniel@iogearbox.net Cc: Lorenz Bauer lmb@cloudflare.com Acked-by: Daniel Borkmann daniel@iogearbox.net Tested-by: Lorenz Bauer lmb@cloudflare.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Liu Jian liujian56@huawei.com --- include/net/net_namespace.h | 4 +--- net/core/filter.c | 8 +++----- net/core/net_namespace.c | 19 +++---------------- 3 files changed, 7 insertions(+), 24 deletions(-)
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index d415ecbd8958..05fd41222a81 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -173,7 +173,7 @@ struct net { struct netns_xfrm xfrm; #endif
- atomic64_t net_cookie; /* written once */ + u64 net_cookie; /* written once */
#if IS_ENABLED(CONFIG_IP_VS) struct netns_ipvs *ipvs; @@ -247,8 +247,6 @@ extern struct list_head net_namespace_list; struct net *get_net_ns_by_pid(pid_t pid); struct net *get_net_ns_by_fd(int fd);
-u64 __net_gen_cookie(struct net *net); - #ifdef CONFIG_SYSCTL void ipx_register_sysctl(void); void ipx_unregister_sysctl(void); diff --git a/net/core/filter.c b/net/core/filter.c index fff5d2d7c6c3..16a2774eecd6 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4698,11 +4698,9 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_ops_proto = {
static u64 __bpf_get_netns_cookie(struct sock *sk) { -#ifdef CONFIG_NET_NS - return __net_gen_cookie(sk ? sk->sk_net.net : &init_net); -#else - return 0; -#endif + const struct net *net = sk ? sock_net(sk) : &init_net; + + return net->net_cookie; }
BPF_CALL_1(bpf_get_netns_cookie_sock, struct sock *, ctx) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index e05dd4f3279a..20a0fc4d059b 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -72,18 +72,6 @@ static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
DEFINE_COOKIE(net_cookie);
-u64 __net_gen_cookie(struct net *net) -{ - while (1) { - u64 res = atomic64_read(&net->net_cookie); - - if (res) - return res; - res = gen_cookie_next(&net_cookie); - atomic64_cmpxchg(&net->net_cookie, 0, res); - } -} - static struct net_generic *net_alloc_generic(void) { struct net_generic *ng; @@ -341,6 +329,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) refcount_set(&net->count, 1); refcount_set(&net->passive, 1); get_random_bytes(&net->hash_mix, sizeof(u32)); + preempt_disable(); + net->net_cookie = gen_cookie_next(&net_cookie); + preempt_enable(); net->dev_base_seq = 1; net->user_ns = user_ns; idr_init(&net->netns_ids); @@ -1128,10 +1119,6 @@ static int __init net_ns_init(void)
rcu_assign_pointer(init_net.gen, ng);
- preempt_disable(); - __net_gen_cookie(&init_net); - preempt_enable(); - down_write(&pernet_ops_rwsem); if (setup_net(&init_net, &init_user_ns)) panic("Could not setup the initial network namespace");