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Tue, 3 Sep 2019 23:18:02 +0000 Received: by smtp431.mail.ne1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID eabded102294463ffa8a3fd86ff39d7b; Tue, 03 Sep 2019 23:17:59 +0000 (UTC) Subject: Re: general protection fault in smack_socket_sendmsg To: Hillf Danton , syzbot Cc: jmorris@namei.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, serge@hallyn.com, syzkaller-bugs@googlegroups.com, casey@schaufler-ca.com References: <20190831053311.15704-1-hdanton@sina.com> From: Casey Schaufler Openpgp: preference=signencrypt Autocrypt: addr=casey@schaufler-ca.com; keydata= mQINBFzV9HABEAC/mmv3jeJyF7lR7QhILYg1+PeBLIMZv7KCzBSc/4ZZipoWdmr77Lel/RxQ 1PrNx0UaM5r6Hj9lJmJ9eg4s/TUBSP67mTx+tsZ1RhG78/WFf9aBe8MSXxY5cu7IUwo0J/CG vdSqACKyYPV5eoTJmnMxalu8/oVUHyPnKF3eMGgE0mKOFBUMsb2pLS/enE4QyxhcZ26jeeS6 3BaqDl1aTXGowM5BHyn7s9LEU38x/y2ffdqBjd3au2YOlvZ+XUkzoclSVfSR29bomZVVyhMB h1jTmX4Ac9QjpwsxihT8KNGvOM5CeCjQyWcW/g8LfWTzOVF9lzbx6IfEZDDoDem4+ZiPsAXC SWKBKil3npdbgb8MARPes2DpuhVm8yfkJEQQmuLYv8GPiJbwHQVLZGQAPBZSAc7IidD2zbf9 XAw1/SJGe1poxOMfuSBsfKxv9ba2i8hUR+PH7gWwkMQaQ97B1yXYxVEkpG8Y4MfE5Vd3bjJU kvQ/tOBUCw5zwyIRC9+7zr1zYi/3hk+OG8OryZ5kpILBNCo+aePeAJ44znrySarUqS69tuXd a3lMPHUJJpUpIwSKQ5UuYYkWlWwENEWSefpakFAIwY4YIBkzoJ/t+XJHE1HTaJnRk6SWpeDf CreF3+LouP4njyeLEjVIMzaEpwROsw++BX5i5vTXJB+4UApTAQARAQABtChDYXNleSBTY2hh dWZsZXIgPGNhc2V5QHNjaGF1Zmxlci1jYS5jb20+iQJUBBMBCAA+FiEEC+9tH1YyUwIQzUIe OKUVfIxDyBEFAlzV9HACGwMFCRLMAwAFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQOKUV fIxDyBG6ag/6AiRl8yof47YOEVHlrmewbpnlBTaYNfJ5cZflNRKRX6t4bp1B2YV1whlDTpiL vNOwFkh+ZE0eI5M4x8Gw2Oiok+4Q5liA9PHTozQYF+Ia+qdL5EehfbLGoEBqklpGvG3h8JsO 7SvONJuFDgvab/U/UriDYycJwzwKZuhVtK9EMpnTtUDyP3DY+Q8h7MWsniNBLVXnh4yBIEJg SSgDn3COpZoFTPGKE+rIzioo/GJe8CTa2g+ZggJiY/myWTS3quG0FMvwvNYvZ4I2g6uxSl7n bZVqAZgqwoTAv1HSXIAn9muwZUJL03qo25PFi2gQmX15BgJKQcV5RL0GHFHRThDS3IyadOgK P2j78P8SddTN73EmsG5OoyzwZAxXfck9A512BfVESqapHurRu2qvMoUkQaW/2yCeRQwGTsFj /rr0lnOBkyC6wCmPSKXe3dT2mnD5KnCkjn7KxLqexKt4itGjJz4/ynD/qh+gL7IPbifrQtVH JI7cr0fI6Tl8V6efurk5RjtELsAlSR6fKV7hClfeDEgLpigHXGyVOsynXLr59uE+g/+InVic jKueTq7LzFd0BiduXGO5HbGyRKw4MG5DNQvC//85EWmFUnDlD3WHz7Hicg95D+2IjD2ZVXJy x3LTfKWdC8bU8am1fi+d6tVEFAe/KbUfe+stXkgmfB7pxqW5Ag0EXNX0cAEQAPIEYtPebJzT wHpKLu1/j4jQcke06Kmu5RNuj1pEje7kX5IKzQSs+CPH0NbSNGvrA4dNGcuDUTNHgb5Be9hF zVqRCEvF2j7BFbrGe9jqMBWHuWheQM8RRoa2UMwQ704mRvKr4sNPh01nKT52ASbWpBPYG3/t WbYaqfgtRmCxBnqdOx5mBJIBh9Q38i63DjQgdNcsTx2qS7HFuFyNef5LCf3jogcbmZGxG/b7 yF4OwmGsVc8ufvlKo5A9Wm+tnRjLr/9Mn9vl5Xa/tQDoPxz26+aWz7j1in7UFzAarcvqzsdM Em6S7uT+qy5jcqyuipuenDKYF/yNOVSNnsiFyQTFqCPCpFihOnuaWqfmdeUOQHCSo8fD4aRF emsuxqcsq0Jp2ODq73DOTsdFxX2ESXYoFt3Oy7QmIxeEgiHBzdKU2bruIB5OVaZ4zWF+jusM Uh+jh+44w9DZkDNjxRAA5CxPlmBIn1OOYt1tsphrHg1cH1fDLK/pDjsJZkiH8EIjhckOtGSb aoUUMMJ85nVhN1EbU/A3DkWCVFEA//Vu1+BckbSbJKE7Hl6WdW19BXOZ7v3jo1q6lWwcFYth esJfk3ZPPJXuBokrFH8kqnEQ9W2QgrjDX3et2WwZFLOoOCItWxT0/1QO4ikcef/E7HXQf/ij Dxf9HG2o5hOlMIAkJq/uLNMvABEBAAGJAjwEGAEIACYWIQQL720fVjJTAhDNQh44pRV8jEPI EQUCXNX0cAIbDAUJEswDAAAKCRA4pRV8jEPIEWkzEACKFUnpp+wIVHpckMfBqN8BE5dUbWJc GyQ7wXWajLtlPdw1nNw0Wrv+ob2RCT7qQlUo6GRLcvj9Fn5tR4hBvR6D3m8aR0AGHbcC62cq I7LjaSDP5j/em4oVL2SMgNTrXgE2w33JMGjAx9oBzkxmKUqprhJomPwmfDHMJ0t7y39Da724 oLPTkQDpJL1kuraM9TC5NyLe1+MyIxqM/8NujoJbWeQUgGjn9uxQAil7o/xSCjrWCP3kZDID vd5ZaHpdl8e1mTExQoKr4EWgaMjmD/a3hZ/j3KfTVNpM2cLfD/QwTMaC2fkK8ExMsz+rUl1H icmcmpptCwOSgwSpPY1Zfio6HvEJp7gmDwMgozMfwQuT9oxyFTxn1X3rn1IoYQF3P8gsziY5 qtTxy2RrgqQFm/hr8gM78RhP54UPltIE96VywviFzDZehMvuwzW//fxysIoK97Y/KBZZOQs+ /T+Bw80Pwk/dqQ8UmIt2ffHEgwCTbkSm711BejapWCfklxkMZDp16mkxSt2qZovboVjXnfuq wQ1QL4o4t1hviM7LyoflsCLnQFJh6RSBhBpKQinMJl/z0A6NYDkQi6vEGMDBWX/M2vk9Jvwa v0cEBfY3Z5oFgkh7BUORsu1V+Hn0fR/Lqq/Pyq+nTR26WzGDkolLsDr3IH0TiAVH5ZuPxyz6 abzjfg== Message-ID: <5f34b914-ca5b-e527-9183-64dc0d83ec9f@schaufler-ca.com> Date: Tue, 3 Sep 2019 16:17:58 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190831053311.15704-1-hdanton@sina.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 8/30/2019 10:33 PM, Hillf Danton wrote: > On Fri, 30 Aug 2019 12:40:07 -0700 >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 6525771f Merge tag 'arc-5.3-rc7' of git://git.kernel.org/p.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=11486cea600000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=58485246ad14eafe >> dashboard link: https://syzkaller.appspot.com/bug?extid=5fd781d646d4fcbdfeb0 >> compiler: clang version 9.0.0 (/home/glider/llvm/clang >> 80fee25776c2fb61e74c1ecb1a523375c2500b69) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+5fd781d646d4fcbdfeb0@syzkaller.appspotmail.com >> >> kasan: CONFIG_KASAN_INLINE enabled >> kasan: GPF could be caused by NULL-ptr deref or user memory access >> general protection fault: 0000 [#1] PREEMPT SMP KASAN >> CPU: 0 PID: 11983 Comm: kworker/0:0 Not tainted 5.3.0-rc6+ #94 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Workqueue: krxrpcd rxrpc_peer_keepalive_worker >> RIP: 0010:smack_socket_sendmsg+0x5b/0x480 security/smack/smack_lsm.c:3677 >> Code: e8 6a 07 71 fe 4c 89 e8 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 ef e8 >> b4 ff a9 fe 4d 8b 65 00 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 >> 74 08 48 89 df e8 96 ff a9 fe 4c 8b 33 49 8d 9e 08 >> RSP: 0018:ffff8881daa1f9c8 EFLAGS: 00010206 >> RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff888048882500 >> RDX: 0000000000000000 RSI: ffff8881daa1fb18 RDI: 0000000000000000 >> RBP: ffff8881daa1fa80 R08: ffffffff8350cc90 R09: ffff8881daa1fb86 >> R10: ffffed103b543f72 R11: 0000000000000000 R12: ffff88803704c594 >> R13: ffff8881daa1fb18 R14: dffffc0000000000 R15: dffffc0000000000 >> FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007f7d4f2b5028 CR3: 000000005e835000 CR4: 00000000001426f0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> security_socket_sendmsg+0x6c/0xd0 security/security.c:1973 >> sock_sendmsg net/socket.c:654 [inline] >> kernel_sendmsg+0x77/0x140 net/socket.c:677 >> rxrpc_send_keepalive+0x254/0x3c0 net/rxrpc/output.c:655 >> rxrpc_peer_keepalive_dispatch net/rxrpc/peer_event.c:369 [inline] >> rxrpc_peer_keepalive_worker+0x76e/0xb40 net/rxrpc/peer_event.c:430 >> process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269 >> worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 >> kthread+0x332/0x350 kernel/kthread.c:255 >> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 >> Modules linked in: >> ---[ end trace 61235a384085b26a ]--- If you want to add a description and signed-off-by I will take this. > > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -3674,7 +3674,7 @@ static int smack_socket_sendmsg(struct s > struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name; > #endif > #ifdef SMACK_IPV6_SECMARK_LABELING > - struct socket_smack *ssp = sock->sk->sk_security; > + struct socket_smack *ssp; > struct smack_known *rsp; > #endif > int rc = 0; > @@ -3684,6 +3684,15 @@ static int smack_socket_sendmsg(struct s > */ > if (sip == NULL) > return 0; > + /* > + * Fine if sock reaped > + */ > + if (!READ_ONCE(sock->sk)) > + return 0; > + > +#ifdef SMACK_IPV6_SECMARK_LABELING > + ssp = sock->sk->sk_security; > +#endif > > switch (sock->sk->sk_family) { > case AF_INET: >