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Message-ID: <CY4PR15MB15756CA2F53B60950E3C409E9A990@CY4PR15MB1575.namprd15.prod.outlook.com>
Date: Wed, 9 May 2018 17:19:27 +0000
From: Jon Maloy <jon.maloy@...csson.com>
To: Eric Dumazet <edumazet@...gle.com>,
"David S . Miller" <davem@...emloft.net>
CC: netdev <netdev@...r.kernel.org>,
Eric Dumazet <eric.dumazet@...il.com>,
Ying Xue <ying.xue@...driver.com>
Subject: RE: [PATCH net] tipc: fix one byte leak in tipc_sk_set_orig_addr()
Acked-by: Jon Maloy <jon.maloy@...csson.com>
Thank you Eric.
> -----Original Message-----
> From: Eric Dumazet [mailto:edumazet@...gle.com]
> Sent: Wednesday, May 09, 2018 09:50
> To: David S . Miller <davem@...emloft.net>
> Cc: netdev <netdev@...r.kernel.org>; Eric Dumazet
> <edumazet@...gle.com>; Eric Dumazet <eric.dumazet@...il.com>; Jon
> Maloy <jon.maloy@...csson.com>; Ying Xue <ying.xue@...driver.com>
> Subject: [PATCH net] tipc: fix one byte leak in tipc_sk_set_orig_addr()
>
> sysbot/KMSAN reported an uninit-value in recvmsg() that I tracked down to
> tipc_sk_set_orig_addr(), missing
> srcaddr->member.scope initialization.
>
> This patches moves srcaddr->sock.scope init to follow fields order and ease
> future verifications.
>
> BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184
> [inline]
> BUG: KMSAN: uninit-value in move_addr_to_user+0x32e/0x530
> net/socket.c:226
> CPU: 0 PID: 4549 Comm: syz-executor287 Not tainted 4.17.0-rc3+ #88
> Hardware name: Google Google Compute Engine/Google Compute Engine,
> BIOS Google 01/01/2011 Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x185/0x1d0 lib/dump_stack.c:113
> kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
> kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1157
> kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copy_to_user
> include/linux/uaccess.h:184 [inline]
> move_addr_to_user+0x32e/0x530 net/socket.c:226
> ___sys_recvmsg+0x4e2/0x810 net/socket.c:2285 __sys_recvmsg
> net/socket.c:2328 [inline] __do_sys_recvmsg net/socket.c:2338 [inline]
> __se_sys_recvmsg net/socket.c:2335 [inline]
> __x64_sys_recvmsg+0x325/0x460 net/socket.c:2335
> do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x4455e9
> RSP: 002b:00007fe3bd36ddb8 EFLAGS: 00000246 ORIG_RAX:
> 000000000000002f
> RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 00000000004455e9
> RDX: 0000000000002002 RSI: 0000000020000400 RDI: 0000000000000003
> RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fff98ce4b6f R14: 00007fe3bd36e9c0 R15: 0000000000000003
>
> Local variable description: ----addr@...sys_recvmsg Variable was created
> at:
> ___sys_recvmsg+0xd5/0x810 net/socket.c:2246 __sys_recvmsg
> net/socket.c:2328 [inline] __do_sys_recvmsg net/socket.c:2338 [inline]
> __se_sys_recvmsg net/socket.c:2335 [inline]
> __x64_sys_recvmsg+0x325/0x460 net/socket.c:2335
>
> Byte 19 of 32 is uninitialized
>
> Fixes: 31c82a2d9d51 ("tipc: add second source address to
> recvmsg()/recvfrom()")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Reported-by: syzbot <syzkaller@...glegroups.com>
> Cc: Jon Maloy <jon.maloy@...csson.com>
> Cc: Ying Xue <ying.xue@...driver.com>
> ---
> net/tipc/socket.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c index
> 252a52ae0893261fc6f146ad81111c59f375fdce..6be21575503aa532014e7aa141
> 5b2bf294757308 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -1516,10 +1516,10 @@ static void tipc_sk_set_orig_addr(struct msghdr
> *m, struct sk_buff *skb)
>
> srcaddr->sock.family = AF_TIPC;
> srcaddr->sock.addrtype = TIPC_ADDR_ID;
> + srcaddr->sock.scope = 0;
> srcaddr->sock.addr.id.ref = msg_origport(hdr);
> srcaddr->sock.addr.id.node = msg_orignode(hdr);
> srcaddr->sock.addr.name.domain = 0;
> - srcaddr->sock.scope = 0;
> m->msg_namelen = sizeof(struct sockaddr_tipc);
>
> if (!msg_in_group(hdr))
> @@ -1528,6 +1528,7 @@ static void tipc_sk_set_orig_addr(struct msghdr
> *m, struct sk_buff *skb)
> /* Group message users may also want to know sending member's id
> */
> srcaddr->member.family = AF_TIPC;
> srcaddr->member.addrtype = TIPC_ADDR_NAME;
> + srcaddr->member.scope = 0;
> srcaddr->member.addr.name.name.type = msg_nametype(hdr);
> srcaddr->member.addr.name.name.instance = TIPC_SKB_CB(skb)-
> >orig_member;
> srcaddr->member.addr.name.domain = 0;
> --
> 2.17.0.441.gb46fe60e1d-goog
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