diff mbox series

[net,1/2] net/af_iucv: fix null pointer dereference on shutdown

Message ID 20201106125008.36478-2-jwi@linux.ibm.com (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series net/iucv: fixes 2020-11-06 | expand

Commit Message

Julian Wiedmann Nov. 6, 2020, 12:50 p.m. UTC 
From: Ursula Braun <ubraun@linux.ibm.com>

syzbot reported the following KASAN finding:

BUG: KASAN: nullptr-dereference in iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
Read of size 2 at addr 000000000000021e by task syz-executor907/519

CPU: 0 PID: 519 Comm: syz-executor907 Not tainted 5.9.0-syzkaller-07043-gbcf9877ad213 #0
Hardware name: IBM 3906 M04 701 (KVM/Linux)
Call Trace:
 [<00000000c576af60>] unwind_start arch/s390/include/asm/unwind.h:65 [inline]
 [<00000000c576af60>] show_stack+0x180/0x228 arch/s390/kernel/dumpstack.c:135
 [<00000000c9dcd1f8>] __dump_stack lib/dump_stack.c:77 [inline]
 [<00000000c9dcd1f8>] dump_stack+0x268/0x2f0 lib/dump_stack.c:118
 [<00000000c5fed016>] print_address_description.constprop.0+0x5e/0x218 mm/kasan/report.c:383
 [<00000000c5fec82a>] __kasan_report mm/kasan/report.c:517 [inline]
 [<00000000c5fec82a>] kasan_report+0x11a/0x168 mm/kasan/report.c:534
 [<00000000c98b5b60>] iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
 [<00000000c98b6262>] iucv_sock_shutdown+0x44a/0x4c0 net/iucv/af_iucv.c:1457
 [<00000000c89d3a54>] __sys_shutdown+0x12c/0x1c8 net/socket.c:2204
 [<00000000c89d3b70>] __do_sys_shutdown net/socket.c:2212 [inline]
 [<00000000c89d3b70>] __s390x_sys_shutdown+0x38/0x48 net/socket.c:2210
 [<00000000c9e36eac>] system_call+0xe0/0x28c arch/s390/kernel/entry.S:415

There is nothing to shutdown if a connection has never been established.
Besides that iucv->hs_dev is not yet initialized if a socket is in
IUCV_OPEN state and iucv->path is not yet initialized if socket is in
IUCV_BOUND state.
So, just skip the shutdown calls for a socket in these states.

Fixes: eac3731bd04c ("s390: Add AF_IUCV socket support")
Fixes: 82492a355fac ("af_iucv: add shutdown for HS transport")
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
---
 net/iucv/af_iucv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Jakub Kicinski Nov. 6, 2020, 4:59 p.m. UTC | #1 
On Fri,  6 Nov 2020 13:50:07 +0100 Julian Wiedmann wrote:
> From: Ursula Braun <ubraun@linux.ibm.com>
> 
> syzbot reported the following KASAN finding:
> 
> BUG: KASAN: nullptr-dereference in iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
> Read of size 2 at addr 000000000000021e by task syz-executor907/519
> 
> CPU: 0 PID: 519 Comm: syz-executor907 Not tainted 5.9.0-syzkaller-07043-gbcf9877ad213 #0
> Hardware name: IBM 3906 M04 701 (KVM/Linux)
> Call Trace:
>  [<00000000c576af60>] unwind_start arch/s390/include/asm/unwind.h:65 [inline]
>  [<00000000c576af60>] show_stack+0x180/0x228 arch/s390/kernel/dumpstack.c:135
>  [<00000000c9dcd1f8>] __dump_stack lib/dump_stack.c:77 [inline]
>  [<00000000c9dcd1f8>] dump_stack+0x268/0x2f0 lib/dump_stack.c:118
>  [<00000000c5fed016>] print_address_description.constprop.0+0x5e/0x218 mm/kasan/report.c:383
>  [<00000000c5fec82a>] __kasan_report mm/kasan/report.c:517 [inline]
>  [<00000000c5fec82a>] kasan_report+0x11a/0x168 mm/kasan/report.c:534
>  [<00000000c98b5b60>] iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
>  [<00000000c98b6262>] iucv_sock_shutdown+0x44a/0x4c0 net/iucv/af_iucv.c:1457
>  [<00000000c89d3a54>] __sys_shutdown+0x12c/0x1c8 net/socket.c:2204
>  [<00000000c89d3b70>] __do_sys_shutdown net/socket.c:2212 [inline]
>  [<00000000c89d3b70>] __s390x_sys_shutdown+0x38/0x48 net/socket.c:2210
>  [<00000000c9e36eac>] system_call+0xe0/0x28c arch/s390/kernel/entry.S:415
> 
> There is nothing to shutdown if a connection has never been established.
> Besides that iucv->hs_dev is not yet initialized if a socket is in
> IUCV_OPEN state and iucv->path is not yet initialized if socket is in
> IUCV_BOUND state.
> So, just skip the shutdown calls for a socket in these states.
> 
> Fixes: eac3731bd04c ("s390: Add AF_IUCV socket support")
> Fixes: 82492a355fac ("af_iucv: add shutdown for HS transport")
> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
> Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>

Fixes tag: Fixes: eac3731bd04c ("s390: Add AF_IUCV socket support")
Has these problem(s):
	- Subject does not match target commit subject
	  Just use
		git log -1 --format='Fixes: %h ("%s")'
Julian Wiedmann Nov. 9, 2020, 7:52 a.m. UTC | #2 
On 06.11.20 18:59, Jakub Kicinski wrote:
> On Fri,  6 Nov 2020 13:50:07 +0100 Julian Wiedmann wrote:
>> From: Ursula Braun <ubraun@linux.ibm.com>
>>
>> syzbot reported the following KASAN finding:
>>
>> BUG: KASAN: nullptr-dereference in iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
>> Read of size 2 at addr 000000000000021e by task syz-executor907/519
>>
>> CPU: 0 PID: 519 Comm: syz-executor907 Not tainted 5.9.0-syzkaller-07043-gbcf9877ad213 #0
>> Hardware name: IBM 3906 M04 701 (KVM/Linux)
>> Call Trace:
>>  [<00000000c576af60>] unwind_start arch/s390/include/asm/unwind.h:65 [inline]
>>  [<00000000c576af60>] show_stack+0x180/0x228 arch/s390/kernel/dumpstack.c:135
>>  [<00000000c9dcd1f8>] __dump_stack lib/dump_stack.c:77 [inline]
>>  [<00000000c9dcd1f8>] dump_stack+0x268/0x2f0 lib/dump_stack.c:118
>>  [<00000000c5fed016>] print_address_description.constprop.0+0x5e/0x218 mm/kasan/report.c:383
>>  [<00000000c5fec82a>] __kasan_report mm/kasan/report.c:517 [inline]
>>  [<00000000c5fec82a>] kasan_report+0x11a/0x168 mm/kasan/report.c:534
>>  [<00000000c98b5b60>] iucv_send_ctrl+0x390/0x3f0 net/iucv/af_iucv.c:385
>>  [<00000000c98b6262>] iucv_sock_shutdown+0x44a/0x4c0 net/iucv/af_iucv.c:1457
>>  [<00000000c89d3a54>] __sys_shutdown+0x12c/0x1c8 net/socket.c:2204
>>  [<00000000c89d3b70>] __do_sys_shutdown net/socket.c:2212 [inline]
>>  [<00000000c89d3b70>] __s390x_sys_shutdown+0x38/0x48 net/socket.c:2210
>>  [<00000000c9e36eac>] system_call+0xe0/0x28c arch/s390/kernel/entry.S:415
>>
>> There is nothing to shutdown if a connection has never been established.
>> Besides that iucv->hs_dev is not yet initialized if a socket is in
>> IUCV_OPEN state and iucv->path is not yet initialized if socket is in
>> IUCV_BOUND state.
>> So, just skip the shutdown calls for a socket in these states.
>>
>> Fixes: eac3731bd04c ("s390: Add AF_IUCV socket support")
>> Fixes: 82492a355fac ("af_iucv: add shutdown for HS transport")
>> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
>> Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
>> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
> 
> Fixes tag: Fixes: eac3731bd04c ("s390: Add AF_IUCV socket support")
> Has these problem(s):
> 	- Subject does not match target commit subject
> 	  Just use
> 		git log -1 --format='Fixes: %h ("%s")'
> 

sigh... yes, that should have been
Fixes: eac3731bd04c ("[S390]: Add AF_IUCV socket support")

Thanks. Will fix up and get you a v2 shortly.
diff mbox series

Patch

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index d80572074667..047238f01ba6 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1434,7 +1434,8 @@  static int iucv_sock_shutdown(struct socket *sock, int how)
 		break;
 	}
 
-	if (how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) {
+	if ((how == SEND_SHUTDOWN || how == SHUTDOWN_MASK) &&
+	    sk->sk_state == IUCV_CONNECTED) {
 		if (iucv->transport == AF_IUCV_TRANS_IUCV) {
 			txmsg.class = 0;
 			txmsg.tag = 0;