3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet <edumazet@xxxxxxxxxx> commit 36f41f8fc6d8aa9f8c9072d66ff7cf9055f5e69b upstream. pfkey_broadcast() might be called from non process contexts, we can not use GFP_KERNEL in these cases [1]. This patch partially reverts commit ba51b6be38c1 ("net: Fix RCU splat in af_key"), only keeping the GFP_ATOMIC forcing under rcu_read_lock() section. [1] : syzkaller reported : in_atomic(): 1, irqs_disabled(): 0, pid: 2932, name: syzkaller183439 3 locks held by syzkaller183439/2932: #0: (&net->xfrm.xfrm_cfg_mutex){+.+.+.}, at: [<ffffffff83b43888>] pfkey_sendmsg+0x4c8/0x9f0 net/key/af_key.c:3649 #1: (&pfk->dump_lock){+.+.+.}, at: [<ffffffff83b467f6>] pfkey_do_dump+0x76/0x3f0 net/key/af_key.c:293 #2: (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] spin_lock_bh include/linux/spinlock.h:304 [inline] #2: (&(&net->xfrm.xfrm_policy_lock)->rlock){+...+.}, at: [<ffffffff83957632>] xfrm_policy_walk+0x192/0xa30 net/xfrm/xfrm_policy.c:1028 CPU: 0 PID: 2932 Comm: syzkaller183439 Not tainted 4.13.0-rc4+ #24 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 ___might_sleep+0x2b2/0x470 kernel/sched/core.c:5994 __might_sleep+0x95/0x190 kernel/sched/core.c:5947 slab_pre_alloc_hook mm/slab.h:416 [inline] slab_alloc mm/slab.c:3383 [inline] kmem_cache_alloc+0x24b/0x6e0 mm/slab.c:3559 skb_clone+0x1a0/0x400 net/core/skbuff.c:1037 pfkey_broadcast_one+0x4b2/0x6f0 net/key/af_key.c:207 pfkey_broadcast+0x4ba/0x770 net/key/af_key.c:281 dump_sp+0x3d6/0x500 net/key/af_key.c:2685 xfrm_policy_walk+0x2f1/0xa30 net/xfrm/xfrm_policy.c:1042 pfkey_dump_sp+0x42/0x50 net/key/af_key.c:2695 pfkey_do_dump+0xaa/0x3f0 net/key/af_key.c:299 pfkey_spddump+0x1a0/0x210 net/key/af_key.c:2722 pfkey_process+0x606/0x710 net/key/af_key.c:2814 pfkey_sendmsg+0x4d6/0x9f0 net/key/af_key.c:3650 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 ___sys_sendmsg+0x755/0x890 net/socket.c:2035 __sys_sendmsg+0xe5/0x210 net/socket.c:2069 SYSC_sendmsg net/socket.c:2080 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2076 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x445d79 RSP: 002b:00007f32447c1dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445d79 RDX: 0000000000000000 RSI: 000000002023dfc8 RDI: 0000000000000008 RBP: 0000000000000086 R08: 00007f32447c2700 R09: 00007f32447c2700 R10: 00007f32447c2700 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe33edec4f R14: 00007f32447c29c0 R15: 0000000000000000 Fixes: ba51b6be38c1 ("net: Fix RCU splat in af_key") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx> Acked-by: David Ahern <dsahern@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- net/key/af_key.c | 48 ++++++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 22 deletions(-) --- a/net/key/af_key.c +++ b/net/key/af_key.c @@ -224,7 +224,7 @@ static int pfkey_broadcast_one(struct sk #define BROADCAST_ONE 1 #define BROADCAST_REGISTERED 2 #define BROADCAST_PROMISC_ONLY 4 -static int pfkey_broadcast(struct sk_buff *skb, +static int pfkey_broadcast(struct sk_buff *skb, gfp_t allocation, int broadcast_flags, struct sock *one_sk, struct net *net) { @@ -274,7 +274,7 @@ static int pfkey_broadcast(struct sk_buf rcu_read_unlock(); if (one_sk != NULL) - err = pfkey_broadcast_one(skb, &skb2, GFP_KERNEL, one_sk); + err = pfkey_broadcast_one(skb, &skb2, allocation, one_sk); kfree_skb(skb2); kfree_skb(skb); @@ -307,7 +307,7 @@ static int pfkey_do_dump(struct pfkey_so hdr = (struct sadb_msg *) pfk->dump.skb->data; hdr->sadb_msg_seq = 0; hdr->sadb_msg_errno = rc; - pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE, + pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE, &pfk->sk, sock_net(&pfk->sk)); pfk->dump.skb = NULL; } @@ -351,7 +351,7 @@ static int pfkey_error(const struct sadb hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t)); - pfkey_broadcast(skb, BROADCAST_ONE, sk, sock_net(sk)); + pfkey_broadcast(skb, GFP_KERNEL, BROADCAST_ONE, sk, sock_net(sk)); return 0; } @@ -1394,7 +1394,7 @@ static int pfkey_getspi(struct sock *sk, xfrm_state_put(x); - pfkey_broadcast(resp_skb, BROADCAST_ONE, sk, net); + pfkey_broadcast(resp_skb, GFP_KERNEL, BROADCAST_ONE, sk, net); return 0; } @@ -1481,7 +1481,7 @@ static int key_notify_sa(struct xfrm_sta hdr->sadb_msg_seq = c->seq; hdr->sadb_msg_pid = c->portid; - pfkey_broadcast(skb, BROADCAST_ALL, NULL, xs_net(x)); + pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, xs_net(x)); return 0; } @@ -1594,7 +1594,7 @@ static int pfkey_get(struct sock *sk, st out_hdr->sadb_msg_reserved = 0; out_hdr->sadb_msg_seq = hdr->sadb_msg_seq; out_hdr->sadb_msg_pid = hdr->sadb_msg_pid; - pfkey_broadcast(out_skb, BROADCAST_ONE, sk, sock_net(sk)); + pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ONE, sk, sock_net(sk)); return 0; } @@ -1699,8 +1699,8 @@ static int pfkey_register(struct sock *s return -ENOBUFS; } - pfkey_broadcast(supp_skb, BROADCAST_REGISTERED, sk, sock_net(sk)); - + pfkey_broadcast(supp_skb, GFP_KERNEL, BROADCAST_REGISTERED, sk, + sock_net(sk)); return 0; } @@ -1718,7 +1718,8 @@ static int unicast_flush_resp(struct soc hdr->sadb_msg_errno = (uint8_t) 0; hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t)); - return pfkey_broadcast(skb, BROADCAST_ONE, sk, sock_net(sk)); + return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ONE, sk, + sock_net(sk)); } static int key_notify_sa_flush(const struct km_event *c) @@ -1739,7 +1740,7 @@ static int key_notify_sa_flush(const str hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t)); hdr->sadb_msg_reserved = 0; - pfkey_broadcast(skb, BROADCAST_ALL, NULL, c->net); + pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net); return 0; } @@ -1796,7 +1797,7 @@ static int dump_sa(struct xfrm_state *x, out_hdr->sadb_msg_pid = pfk->dump.msg_portid; if (pfk->dump.skb) - pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE, + pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE, &pfk->sk, sock_net(&pfk->sk)); pfk->dump.skb = out_skb; @@ -1884,7 +1885,7 @@ static int pfkey_promisc(struct sock *sk new_hdr->sadb_msg_errno = 0; } - pfkey_broadcast(skb, BROADCAST_ALL, NULL, sock_net(sk)); + pfkey_broadcast(skb, GFP_KERNEL, BROADCAST_ALL, NULL, sock_net(sk)); return 0; } @@ -2218,7 +2219,7 @@ static int key_notify_policy(struct xfrm out_hdr->sadb_msg_errno = 0; out_hdr->sadb_msg_seq = c->seq; out_hdr->sadb_msg_pid = c->portid; - pfkey_broadcast(out_skb, BROADCAST_ALL, NULL, xp_net(xp)); + pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ALL, NULL, xp_net(xp)); return 0; } @@ -2438,7 +2439,7 @@ static int key_pol_get_resp(struct sock out_hdr->sadb_msg_errno = 0; out_hdr->sadb_msg_seq = hdr->sadb_msg_seq; out_hdr->sadb_msg_pid = hdr->sadb_msg_pid; - pfkey_broadcast(out_skb, BROADCAST_ONE, sk, xp_net(xp)); + pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_ONE, sk, xp_net(xp)); err = 0; out: @@ -2692,7 +2693,7 @@ static int dump_sp(struct xfrm_policy *x out_hdr->sadb_msg_pid = pfk->dump.msg_portid; if (pfk->dump.skb) - pfkey_broadcast(pfk->dump.skb, BROADCAST_ONE, + pfkey_broadcast(pfk->dump.skb, GFP_ATOMIC, BROADCAST_ONE, &pfk->sk, sock_net(&pfk->sk)); pfk->dump.skb = out_skb; @@ -2749,7 +2750,7 @@ static int key_notify_policy_flush(const hdr->sadb_msg_satype = SADB_SATYPE_UNSPEC; hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t)); hdr->sadb_msg_reserved = 0; - pfkey_broadcast(skb_out, BROADCAST_ALL, NULL, c->net); + pfkey_broadcast(skb_out, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net); return 0; } @@ -2811,7 +2812,7 @@ static int pfkey_process(struct sock *sk void *ext_hdrs[SADB_EXT_MAX]; int err; - pfkey_broadcast(skb_clone(skb, GFP_KERNEL), + pfkey_broadcast(skb_clone(skb, GFP_KERNEL), GFP_KERNEL, BROADCAST_PROMISC_ONLY, NULL, sock_net(sk)); memset(ext_hdrs, 0, sizeof(ext_hdrs)); @@ -3033,7 +3034,8 @@ static int key_notify_sa_expire(struct x out_hdr->sadb_msg_seq = 0; out_hdr->sadb_msg_pid = 0; - pfkey_broadcast(out_skb, BROADCAST_REGISTERED, NULL, xs_net(x)); + pfkey_broadcast(out_skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, + xs_net(x)); return 0; } @@ -3223,7 +3225,8 @@ static int pfkey_send_acquire(struct xfr xfrm_ctx->ctx_len); } - return pfkey_broadcast(skb, BROADCAST_REGISTERED, NULL, xs_net(x)); + return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, + xs_net(x)); } static struct xfrm_policy *pfkey_compile_policy(struct sock *sk, int opt, @@ -3421,7 +3424,8 @@ static int pfkey_send_new_mapping(struct n_port->sadb_x_nat_t_port_port = sport; n_port->sadb_x_nat_t_port_reserved = 0; - return pfkey_broadcast(skb, BROADCAST_REGISTERED, NULL, xs_net(x)); + return pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_REGISTERED, NULL, + xs_net(x)); } #ifdef CONFIG_NET_KEY_MIGRATE @@ -3613,7 +3617,7 @@ static int pfkey_send_migrate(const stru } /* broadcast migrate message to sockets */ - pfkey_broadcast(skb, BROADCAST_ALL, NULL, &init_net); + pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, &init_net); return 0;