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* net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
@ 2016-11-02 18:44 ` Andrey Konovalov
  0 siblings, 0 replies; 10+ messages in thread
From: Andrey Konovalov @ 2016-11-02 18:44 UTC (permalink / raw)
  To: Gerrit Renker, David S. Miller, dccp, netdev, LKML
  Cc: Dmitry Vyukov, Alexander Potapenko, Kostya Serebryany,
	Eric Dumazet, syzkaller

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!

^ permalink raw reply	[flat|nested] 10+ messages in thread
* net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
@ 2016-11-02 18:44 ` Andrey Konovalov
  0 siblings, 0 replies; 10+ messages in thread
From: Andrey Konovalov @ 2016-11-02 18:44 UTC (permalink / raw)
  To: dccp

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!

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
  2016-11-02 18:44 ` Andrey Konovalov
@ 2016-11-02 20:16   ` Eric Dumazet
  -1 siblings, 0 replies; 10+ messages in thread
From: Eric Dumazet @ 2016-11-02 20:16 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: Gerrit Renker, David S. Miller, dccp, netdev, LKML,
	Dmitry Vyukov, Alexander Potapenko, Kostya Serebryany,
	Eric Dumazet, syzkaller

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))

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
@ 2016-11-02 20:16   ` Eric Dumazet
  0 siblings, 0 replies; 10+ messages in thread
From: Eric Dumazet @ 2016-11-02 20:16 UTC (permalink / raw)
  To: dccp

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))



^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
  2016-11-02 18:44 ` Andrey Konovalov
@ 2016-11-02 20:26     ` Andrey Konovalov
  -1 siblings, 0 replies; 10+ messages in thread
From: Andrey Konovalov @ 2016-11-02 20:26 UTC (permalink / raw)
  To: Eric Dumazet
  Cc: Gerrit Renker, David S. Miller, dccp, netdev, LKML,
	Dmitry Vyukov, Alexander Potapenko, Kostya Serebryany,
	Eric Dumazet, syzkaller

Hi Eric,

Your patch fixes the issue.

Tested-by: Andrey Konovalov <andreyknvl@google.com>

Thanks!

On Wed, Nov 2, 2016 at 9:16 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> 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))
>
>

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb
@ 2016-11-02 20:26     ` Andrey Konovalov
  0 siblings, 0 replies; 10+ messages in thread
From: Andrey Konovalov @ 2016-11-02 20:26 UTC (permalink / raw)
  To: dccp

Hi Eric,

Your patch fixes the issue.

Tested-by: Andrey Konovalov <andreyknvl@google.com>

Thanks!

On Wed, Nov 2, 2016 at 9:16 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> 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))
>
>

^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH net] dccp: do not release listeners too soon
@ 2016-11-03  0:14   ` Eric Dumazet
  0 siblings, 0 replies; 10+ messages in thread
From: Eric Dumazet @ 2016-11-03  0:14 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: Gerrit Renker, David S. Miller, dccp, netdev, Dmitry Vyukov,
	Alexander Potapenko, Kostya Serebryany, Eric Dumazet, syzkaller

From: Eric Dumazet <edumazet@google.com>

Andrey Konovalov reported following error while fuzzing with syzkaller :

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

It turns out DCCP calls __sk_receive_skb(), and this broke when
lookups no longer took a reference on listeners.

Fix this issue by adding a @refcounted parameter to __sk_receive_skb(),
so that sock_put() is used only when needed.

Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
---
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))

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH net] dccp: do not release listeners too soon
@ 2016-11-03  0:14   ` Eric Dumazet
  0 siblings, 0 replies; 10+ messages in thread
From: Eric Dumazet @ 2016-11-03  0:14 UTC (permalink / raw)
  To: dccp

From: Eric Dumazet <edumazet@google.com>

Andrey Konovalov reported following error while fuzzing with syzkaller :

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

It turns out DCCP calls __sk_receive_skb(), and this broke when
lookups no longer took a reference on listeners.

Fix this issue by adding a @refcounted parameter to __sk_receive_skb(),
so that sock_put() is used only when needed.

Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
---
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))



^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH net] dccp: do not release listeners too soon
  2016-11-03  0:14   ` Eric Dumazet
@ 2016-11-03 20:19     ` David Miller
  -1 siblings, 0 replies; 10+ messages in thread
From: David Miller @ 2016-11-03 20:19 UTC (permalink / raw)
  To: eric.dumazet
  Cc: andreyknvl, gerrit, dccp, netdev, dvyukov, glider, kcc, edumazet,
	syzkaller

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 02 Nov 2016 17:14:41 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> Andrey Konovalov reported following error while fuzzing with syzkaller :
 ...
> It turns out DCCP calls __sk_receive_skb(), and this broke when
> lookups no longer took a reference on listeners.
> 
> Fix this issue by adding a @refcounted parameter to __sk_receive_skb(),
> so that sock_put() is used only when needed.
> 
> Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Andrey Konovalov <andreyknvl@google.com>
> Tested-by: Andrey Konovalov <andreyknvl@google.com>

Applied and queued up for -stable.

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH net] dccp: do not release listeners too soon
@ 2016-11-03 20:19     ` David Miller
  0 siblings, 0 replies; 10+ messages in thread
From: David Miller @ 2016-11-03 20:19 UTC (permalink / raw)
  To: dccp

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 02 Nov 2016 17:14:41 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> Andrey Konovalov reported following error while fuzzing with syzkaller :
 ...
> It turns out DCCP calls __sk_receive_skb(), and this broke when
> lookups no longer took a reference on listeners.
> 
> Fix this issue by adding a @refcounted parameter to __sk_receive_skb(),
> so that sock_put() is used only when needed.
> 
> Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Andrey Konovalov <andreyknvl@google.com>
> Tested-by: Andrey Konovalov <andreyknvl@google.com>

Applied and queued up for -stable.

^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2016-11-03 20:19 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-11-02 18:44 net/dccp: null-ptr-deref in dccp_v4_rcv/selinux_socket_sock_rcv_skb Andrey Konovalov
2016-11-02 18:44 ` Andrey Konovalov
2016-11-02 20:16 ` Eric Dumazet
2016-11-02 20:16   ` Eric Dumazet
2016-11-02 20:26   ` Andrey Konovalov
2016-11-02 20:26     ` Andrey Konovalov
2016-11-03  0:14 ` [PATCH net] dccp: do not release listeners too soon Eric Dumazet
2016-11-03  0:14   ` Eric Dumazet
2016-11-03 20:19   ` David Miller
2016-11-03 20:19     ` David Miller

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