On Wed, 2016-11-02 at 19:44 +0100, Andrey Konovalov wrote: > Hi, > > I've got the following error report while running the syzkaller fuzzer: > > IPv4: Attempt to release alive inet socket ffff880068e98940 > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] SMP KASAN > Modules linked in: > CPU: 1 PID: 3905 Comm: a.out Not tainted 4.9.0-rc3+ #333 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > task: ffff88006b9e0000 task.stack: ffff880068770000 > RIP: 0010:[<ffffffff819ead5f>] [<ffffffff819ead5f>] > selinux_socket_sock_rcv_skb+0xff/0x6a0 security/selinux/hooks.c:4639 > RSP: 0018:ffff8800687771c8 EFLAGS: 00010202 > RAX: ffff88006b9e0000 RBX: 1ffff1000d0eee3f RCX: 1ffff1000d1d312a > RDX: 1ffff1000d1d31a6 RSI: dffffc0000000000 RDI: 0000000000000010 > RBP: ffff880068777360 R08: 0000000000000000 R09: 0000000000000002 > R10: dffffc0000000000 R11: 0000000000000006 R12: ffff880068e98940 > R13: 0000000000000002 R14: ffff880068777338 R15: 0000000000000000 > FS: 00007f00ff760700(0000) GS:ffff88006cd00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020008000 CR3: 000000006a308000 CR4: 00000000000006e0 > Stack: > ffff8800687771e0 ffffffff812508a5 ffff8800686f3168 0000000000000007 > ffff88006ac8cdfc ffff8800665ea500 0000000041b58ab3 ffffffff847b5480 > ffffffff819eac60 ffff88006b9e0860 ffff88006b9e0868 ffff88006b9e07f0 > Call Trace: > [<ffffffff819c8dd5>] security_sock_rcv_skb+0x75/0xb0 security/security.c:1317 > [<ffffffff82c2a9e7>] sk_filter_trim_cap+0x67/0x10e0 net/core/filter.c:81 > [<ffffffff82b81e60>] __sk_receive_skb+0x30/0xa00 net/core/sock.c:460 > [<ffffffff838bbf12>] dccp_v4_rcv+0xdb2/0x1910 net/dccp/ipv4.c:873 > [<ffffffff83069d22>] ip_local_deliver_finish+0x332/0xad0 > net/ipv4/ip_input.c:216 > [< inline >] NF_HOOK_THRESH ./include/linux/netfilter.h:232 > [< inline >] NF_HOOK ./include/linux/netfilter.h:255 > [<ffffffff8306abd2>] ip_local_deliver+0x1c2/0x4b0 net/ipv4/ip_input.c:257 > [< inline >] dst_input ./include/net/dst.h:507 > [<ffffffff83068500>] ip_rcv_finish+0x750/0x1c40 net/ipv4/ip_input.c:396 > [< inline >] NF_HOOK_THRESH ./include/linux/netfilter.h:232 > [< inline >] NF_HOOK ./include/linux/netfilter.h:255 > [<ffffffff8306b82f>] ip_rcv+0x96f/0x12f0 net/ipv4/ip_input.c:487 > [<ffffffff82bd9fb7>] __netif_receive_skb_core+0x1897/0x2a50 net/core/dev.c:4213 > [<ffffffff82bdb19a>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4251 > [<ffffffff82bdb493>] netif_receive_skb_internal+0x1b3/0x390 net/core/dev.c:4279 > [<ffffffff82bdb6b8>] netif_receive_skb+0x48/0x250 net/core/dev.c:4303 > [<ffffffff8241fc75>] tun_get_user+0xbd5/0x28a0 drivers/net/tun.c:1308 > [<ffffffff82421b5a>] tun_chr_write_iter+0xda/0x190 drivers/net/tun.c:1332 > [< inline >] new_sync_write fs/read_write.c:499 > [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512 > [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560 > [< inline >] SYSC_write fs/read_write.c:607 > [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599 > [<ffffffff83fc02c1>] entry_SYSCALL_64_fastpath+0x1f/0xc2 > arch/x86/entry/entry_64.S:209 > Code: 31 45 84 c0 74 0a 41 80 f8 01 0f 8e 26 04 00 00 49 8d 7f 10 49 > ba 00 00 00 00 00 fc ff df 45 0f b7 6c 24 10 49 89 f9 49 c1 e9 03 <47> > 0f b6 1c 11 45 84 db 74 0a 41 80 fb 03 0f 8e 01 04 00 00 41 > RIP [<ffffffff819ead5f>] selinux_socket_sock_rcv_skb+0xff/0x6a0 > security/selinux/hooks.c:4639 > RSP <ffff8800687771c8> > ---[ end trace 6c39677dc406a11b ]--- > Kernel panic - not syncing: Fatal exception in interrupt > Kernel Offset: disabled > ---[ end Kernel panic - not syncing: Fatal exception in interrupt > > On commit 0c183d92b20b5c84ca655b45ef57b3318b83eb9e (Oct 31). > > Thanks! Please try the following patch, thanks ! diff --git a/include/net/sock.h b/include/net/sock.h index 73c6b008f1b7..92b269709b9a 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1596,11 +1596,11 @@ static inline void sock_put(struct sock *sk) void sock_gen_put(struct sock *sk); int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested, - unsigned int trim_cap); + unsigned int trim_cap, bool refcounted); static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested) { - return __sk_receive_skb(sk, skb, nested, 1); + return __sk_receive_skb(sk, skb, nested, 1, true); } static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) diff --git a/net/core/sock.c b/net/core/sock.c index df171acfe232..5e3ca414357e 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -453,7 +453,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) EXPORT_SYMBOL(sock_queue_rcv_skb); int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, - const int nested, unsigned int trim_cap) + const int nested, unsigned int trim_cap, bool refcounted) { int rc = NET_RX_SUCCESS; @@ -487,7 +487,8 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, bh_unlock_sock(sk); out: - sock_put(sk); + if (refcounted) + sock_put(sk); return rc; discard_and_relse: kfree_skb(skb); diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 345a3aeb8c7e..dff7cfab1da4 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -868,7 +868,7 @@ static int dccp_v4_rcv(struct sk_buff *skb) goto discard_and_relse; nf_reset(skb); - return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4); + return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, refcounted); no_dccp_socket: if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index 3828f94b234c..09c4e19aa285 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -738,7 +738,8 @@ static int dccp_v6_rcv(struct sk_buff *skb) if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; - return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4) ? -1 : 0; + return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4, + refcounted) ? -1 : 0; no_dccp_socket: if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html