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Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value
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- Subject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value
- From: "Zvi Vered" <veredz72@xxxxxxxxx>
- Reply-to: libssh@xxxxxxxxxx
- Date: Thu, 1 May 2014 19:42:48 +0300
- To: <libssh@xxxxxxxxxx>
Hi Aris, I did not do any changes in libssl. Can you point to the exact code in libssl where random numbers are created ? I will ask Windriver how to port this code to vxWorks. Thanks, Zvika-----Original Message----- From: Aris Adamantiadis
Sent: Wednesday, April 30, 2014 11:14 PM To: libssh@xxxxxxxxxxSubject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value
Zvi, Please tell me the random in libssh/openssl doesn't come out of rand(). This function is highly insecure and should not be used for cryptography. There are two acceptable ways of generating random, one of them is a /dev/?random device, the other is an EGD (entropy gathering daemon). The 1024 bits integer is a bignum. It is generated by the libcrypto library. I don't understand why the generated number is zero. Did you modify libcrypto/libssl ? Does openssh run normally ? Aris Le 29/04/14 23:18, Zvi Vered a écrit :
Hi Aris, vxWorks has no /dev/random or /dev/urandom. But it does have the function: int rand () Can you tell what routine generates the "public part of the DH handshake " ? What is the "1024 bits long integer" ? Is it a struct ? What is PRNG ? Is it calculated in "pki_key_dup" ? Thank you for your help ! Zvika -----Original Message----- From: Aris Adamantiadis Sent: Tuesday, April 29, 2014 11:01 PM To: libssh@xxxxxxxxxx Subject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value Hi, Your capture tells me that the public part of the DH handshake generated by client is invalid (it is equal to 1 when it should be a 1024 bits long integer). I have no idea how that could happen. It is possible that the PRNG returns 0 and so the g^x ends up being 1. But this is not consistent with the random cookie looking random. Does VXWork have a /dev/random or /dev/urandom device ? Aris Le 27/04/14 16:07, Zvi Vered a écrit :Hi Aris, Attached the cap file as saved with Wireshark. I hope this is the right cap format. Can you understand why the server sends a "disconnect" ? The client is: 128.172.5.22 The server is: 128.172.82.55 Thanks, Zvika -----Original Message----- From: Aris Adamantiadis Sent: Thursday, April 24, 2014 11:57 PM To: libssh@xxxxxxxxxx Subject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value Please upload you .cap to cloudshark.org or attach it to the email, I can't help without seeing the content of packets. Aris Le 24/04/14 22:46, Zvi Vered a écrit :Hi Aris, Is it possible to upload files ? Attached a snapshot from wireshark. It starts from the ARP request the clients sends till "Server: Disconnect". Thanks, Zvika -----Original Message----- From: Aris Adamantiadis Sent: Thursday, April 24, 2014 10:52 PM To: libssh@xxxxxxxxxx Subject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value Can you please record a tcpdump capture with tcpdump or wireshark and post it on cloudshark ? This happens pre-encryption. Aris Le 24/04/14 21:45, Zvi Vered a écrit :Hi Aris, It happens every time. Thanks, Zvika -----Original Message----- From: Aris Adamantiadis Sent: Thursday, April 24, 2014 9:23 PM To: libssh@xxxxxxxxxx Subject: Re: ssh_connect fails: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value Hi, Does it happen every time you connect or only sometimes ? It's very strange. Aris Le 24/04/14 20:14, Zvi Vered a écrit :Dear Members, I ported libssh-0.6.3 and openssl-1.0.1g to vxWorks 6.9.2 (with very few code changes). Upon ssh_connect I got the messages listed below. As you can see the connection fails and the final message is: ssh_packet_disconnect_callback: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value On the server side (running under RHEL 5.3) I got the following messages in /var/log/secure: expecting SSH2_MSG_KEXDH_INIT invalid public DH value (1 / 2048) Disconnecting: bad client public DH value What can cause this problem ? Thanks, Zvika ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -> [1970/01/01 00:00:00.000000, 1] ssh_connect: libssh 0.6.3 (c) 2003-2014 Aris Adamantiadis, Andreas Schneider, and libssh contributors. Distributed under the LGPL, please refer to COPYING file for information about your rights, using threading threads_noop [1970/01/01 00:00:00.000064, 3] getai: host 128.172.82.55 matches an IP address [1970/01/01 00:00:00.000000, 2] ssh_socket_connect: Nonblocking connection socket: 6 [1970/01/01 00:00:00.808925489, 2] ssh_connect: Socket connecting, now waiting for the callbacks to work [1974/09/05 19:44:04.145667616, 3] ssh_connect: ssh_connect: Actual timeout : 10000 [2097/01/10 06:02:22.-286331154, 3] ssh_socket_pollcallback: Received POLLOUT in connecting state [2097/01/10 06:02:22.139554400, 1] socket_callback_connected: Socket connection callback: 1 (0) [1970/02/21 20:18:44.139848112, 3] callback_receive_banner: Received banner: SSH-2.0-OpenSSH_4.3 [1974/09/05 19:43:04.000019, 1] ssh_client_connection_callback: SSH server banner: SSH-2.0-OpenSSH_4.3 [1970/01/01 00:00:00.000000, 1] ssh_analyze_banner: Analyzing banner: SSH-2.0-OpenSSH_4.3 [1974/06/07 14:41:52.147642244, 1] ssh_analyze_banner: We are talking to an OpenSSH client version: 4.3 (40300) [1970/01/01 00:00:00.000000, 3] ssh_socket_unbuffered_write: Enabling POLLOUT for socket [1970/01/01 00:17:04.131080, 3] ssh_packet_socket_callback: packet: read type 20 [len=700,padding=7,comp=692,payload=692] [1974/08/13 22:00:40.145663148, 3] ssh_packet_process: Dispatching handler for packet type 20 [1970/02/23 18:37:26.147642212, 4] ssh_list_kex: kex algos: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: server host key algo: ssh-rsa,ssh-dss [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: encryption client->server: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@xxxxxxxxxxxxxx,aes128-ctr,aes192-ctr,aes256-ctr [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: encryption server->client: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@xxxxxxxxxxxxxx,aes128-ctr,aes192-ctr,aes256-ctr [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: mac algo client->server: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: mac algo server->client: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: compression algo client->server: none,zlib@xxxxxxxxxxx [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: compression algo server->client: none,zlib@xxxxxxxxxxx [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: languages client->server: [1974/08/13 21:56:40.147642212, 4] ssh_list_kex: languages server->client: [1970/01/01 00:00:00.000000, 4] ssh_list_kex: kex algos: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 [1974/08/13 21:56:04.000000, 4] ssh_list_kex: server host key algo: ssh-rsa,ssh-dss [1974/08/13 21:56:04.000000, 4] ssh_list_kex: encryption client->server: aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,blowfish-cbc,3des-cbc,des-cbc-ssh1 [1974/08/13 21:56:04.000000, 4] ssh_list_kex: encryption server->client: aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,blowfish-cbc,3des-cbc,des-cbc-ssh1 [1974/08/13 21:56:04.000000, 4] ssh_list_kex: mac algo client->server: hmac-sha1 [1974/08/13 21:56:04.000000, 4] ssh_list_kex: mac algo server->client: hmac-sha1 [1974/08/13 21:56:04.000000, 4] ssh_list_kex: compression algo client->server: none [1974/08/13 21:56:04.000000, 4] ssh_list_kex: compression algo server->client: none [1974/08/13 21:56:04.000000, 4] ssh_list_kex: languages client->server: [1974/08/13 21:56:04.000000, 4] ssh_list_kex: languages server->client: [1974/08/13 21:36:36.000000, 3] packet_send2: packet: wrote [len=364,padding=6,comp=357,payload=357] [1974/08/13 21:55:44.145662852, 3] packet_send2: packet: wrote [len=12,padding=5,comp=6,payload=6] [1970/01/01 00:00:00.000000, 3] ssh_socket_unbuffered_write: Enabling POLLOUT for socket [1970/01/01 00:17:04.131080, 3] ssh_packet_socket_callback: packet: read type 1 [len=44,padding=4,comp=39,payload=39] [1974/08/13 22:00:40.145663148, 3] ssh_packet_process: Dispatching handler for packet type 1 [1970/01/01 00:00:00.000000, 3] ssh_packet_disconnect_callback: Received SSH_MSG_DISCONNECT 33554432:bad client public DH value [1970/01/01 00:00:16.139880016, 1] ssh_packet_disconnect_callback: Received SSH_MSG_DISCONNECT: 33554432:bad client public DH value [1974/08/13 23:13:32.145667616, 3] ssh_connect: ssh_connect: Actual state : 9 ssh_connect failed: Received SSH_MSG_DISCONNECT: 33554432:bad client public DH value
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