Hi Konstantin, Would you be able to run Dropbear under inetd and see if that helps? uClinux generally requires that - though it's not obvious to me how it could cause this crash. Is there any chance of getting a backtrace where it is crashing? The RSA and DSS crashes are at different spots, so I guess some global state might be getting corrupted. When it successfully runs (no HostKeyAlgorithms) I assume it is using ecdsa for the hostkey?
Cheers, Matt > On Wed 18/1/2017, at 8:53 am, Konstantin Lazarev <cnlaza...@gmail.com> wrote: > > Hello, > > I see consistent SEGV when running Dropbear v2016.74 in uClinux 2.6.33 on > ARMv7m-cortex-m4 processor > Faults happen only if client specifying HostKeyAlgorithms option. > Please see verbose output from client and dropbear: > > [root@172.17.152.20 <mailto:root@172.17.152.20>: ]# dropbear -V > Dropbear v2016.74 > > ---------------------------------------- from client > --------------------------------------------------------------------------- > $ssh -v -o HostKeyAlgorithms=ssh-dss root@172.17.152.20 > <mailto:root@172.17.152.20> > OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g 1 Mar 2016 > debug1: Reading configuration data /etc/ssh/ssh_config > debug1: /etc/ssh/ssh_config line 19: Applying options for * > debug1: Connecting to 172.17.152.20 [172.17.152.20] port 22. > debug1: Connection established. > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_rsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_rsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_dsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_dsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ecdsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ecdsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ed25519 type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ed25519-cert type -1 > debug1: Enabling compatibility mode for protocol 2.0 > debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 > debug1: Remote protocol version 2.0, remote software version dropbear_2016.74 > debug1: no match: dropbear_2016.74 > debug1: Authenticating to 172.17.152.20:22 <http://172.17.152.20:22/> as > 'root' > debug1: SSH2_MSG_KEXINIT sent > debug1: SSH2_MSG_KEXINIT received > debug1: kex: algorithm: curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org> > debug1: kex: host key algorithm: ssh-dss > debug1: kex: server->client cipher: aes128-ctr MAC: hmac-sha2-256 > compression: none > debug1: kex: client->server cipher: aes128-ctr MAC: hmac-sha2-256 > compression: none > debug1: expecting SSH2_MSG_KEX_ECDH_REPLY > Connection closed by 172.17.152.20 port 22 > > ---------------------------------------- from dropbear > --------------------------------------------------------------------------- > [root@172.17.152.20 <mailto:root@172.17.152.20>: ]# dropbear -v -F > TRACE (2934) 0.000000: enter buf_get_rsa_priv_key > TRACE (2934) 0.000702: enter buf_get_rsa_pub_key > TRACE (2934) 0.003142: leave buf_get_rsa_pub_key: success > TRACE (2934) 0.006667: leave buf_get_rsa_priv_key > TRACE (2934) 0.007364: leave loadhostkey > TRACE (2934) 0.008475: enter buf_get_dss_pub_key > TRACE (2934) 0.029568: leave buf_get_dss_pub_key: success > TRACE (2934) 0.030491: leave loadhostkey > TRACE (2934) 0.031491: enter buf_get_ecdsa_priv_key > TRACE (2934) 0.032079: enter buf_get_ecc_raw_pubkey > TRACE (2934) 0.037565: leave buf_get_ecdsa_pub_key > TRACE (2934) 0.038492: leave loadhostkey > TRACE (2934) 0.049830: Disabling key type 2 > TRACE (2934) 0.050450: Disabling key type 3 > TRACE (2934) 0.110221: listensockets: 1 to try > TRACE (2934) 0.111137: listening on ':22' > TRACE (2934) 0.111844: enter dropbear_listen > TRACE (2934) 0.112368: dropbear_listen: all interfaces > TRACE (2934) 0.113916: bind(22) failed > TRACE (2934) 0.114629: leave dropbear_listen: success, 1 socks bound > TRACE (2934) 0.115578: set_listen_fast_open failed for socket 3: Protocol > not available > [2934] Jan 01 00:16:07 Not backgrounding > [2934] Jan 01 00:16:12 Child connection from 172.17.163.3:42180 > <http://172.17.163.3:42180/> > TRACE (2934) 5.057261: enter session_init > TRACE (2934) 5.058028: setnonblocking: 5 > TRACE (2934) 5.058726: leave setnonblocking > TRACE (2934) 5.059736: setnonblocking: 5 > TRACE (2934) 5.060404: leave setnonblocking > TRACE (2934) 5.060983: update_channel_prio > TRACE (2934) 5.061525: update_channel_prio: not any > TRACE (2934) 5.062037: Dropbear priority transitioning 10 -> 11 > TRACE (2934) 5.062814: setnonblocking: 3 > TRACE (2934) 5.063414: leave setnonblocking > TRACE (2934) 5.063894: setnonblocking: 6 > TRACE (2934) 5.064461: leave setnonblocking > TRACE (2934) 5.065835: leave session_init > TRACE (2934) 5.066793: kexinitialise() > TRACE (2934) 5.067877: DATAALLOWED=0 > TRACE (2934) 5.068411: -> KEXINIT > TRACE (2934) 5.069399: enter set_connect_fds > TRACE (2934) 5.070012: maybe_empty_reply_queue - no data allowed > TRACE (2934) 5.070558: enter handle_connect_fds > TRACE (2934) 5.071036: leave handle_connect_fds - end iter > TRACE (2934) 5.071895: empty queue dequeing > TRACE (2934) 5.073045: enter set_connect_fds > TRACE (2934) 5.073657: enter ident_readln > TRACE (2934) 5.077698: leave ident_readln: return 40 > TRACE (2934) 5.078328: remoteident: SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 > TRACE (2934) 5.079270: maybe_empty_reply_queue - no data allowed > TRACE (2934) 5.079801: enter handle_connect_fds > TRACE (2934) 5.080287: leave handle_connect_fds - end iter > TRACE (2934) 5.080824: enter set_connect_fds > TRACE (2934) 5.081611: process_packet: packet type = 20, len 1048 > TRACE (2934) 5.082330: got expected packet 20 during kexinit > TRACE (2934) 5.082944: <- KEXINIT > TRACE (2934) 5.083440: enter recv_msg_kexinit > TRACE (2934) 5.084130: buf_match_algo: curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org>,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c > TRACE (2934) 5.084896: kexguess2 1 > TRACE (2934) 5.085457: kex algo curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org> > TRACE (2934) 5.086025: buf_match_algo: ssh-dss > TRACE (2934) 5.086588: hostkey algo ssh-dss > TRACE (2934) 5.087174: buf_match_algo: chacha20-poly1...@openssh.com > <mailto:chacha20-poly1...@openssh.com>,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com > <mailto:aes128-...@openssh.com>,aes256-...@openssh.com > <mailto:aes256-...@openssh.com>,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc > TRACE (2934) 5.087844: enc c2s is aes128-ctr > TRACE (2934) 5.088424: buf_match_algo: chacha20-poly1...@openssh.com > <mailto:chacha20-poly1...@openssh.com>,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com > <mailto:aes128-...@openssh.com>,aes256-...@openssh.com > <mailto:aes256-...@openssh.com>,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc > TRACE (2934) 5.089247: enc s2c is aes128-ctr > TRACE (2934) 5.089838: buf_match_algo: umac-64-...@openssh.com > <mailto:umac-64-...@openssh.com>,umac-128-...@openssh.com > <mailto:umac-128-...@openssh.com>,hmac-sha2-256-...@openssh.com > <mailto:hmac-sha2-256-...@openssh.com>,hmac-sha2-512-...@openssh.com > <mailto:hmac-sha2-512-...@openssh.com>,hmac-sha1-...@openssh.com > <mailto:hmac-sha1-...@openssh.com>,umac...@openssh.com > <mailto:umac...@openssh.com>,umac-...@openssh.com > <mailto:umac-...@openssh.com>,hmac-sha2-256,hmac-sha2-512,hmac-sha1 > TRACE (2934) 5.090572: hash c2s is hmac-sha2-256 > TRACE (2934) 5.091158: buf_match_algo: umac-64-...@openssh.com > <mailto:umac-64-...@openssh.com>,umac-128-...@openssh.com > <mailto:umac-128-...@openssh.com>,hmac-sha2-256-...@openssh.com > <mailto:hmac-sha2-256-...@openssh.com>,hmac-sha2-512-...@openssh.com > <mailto:hmac-sha2-512-...@openssh.com>,hmac-sha1-...@openssh.com > <mailto:hmac-sha1-...@openssh.com>,umac...@openssh.com > <mailto:umac...@openssh.com>,umac-...@openssh.com > <mailto:umac-...@openssh.com>,hmac-sha2-256,hmac-sha2-512,hmac-sha1 > TRACE (2934) 5.091877: hash s2c is hmac-sha2-256 > TRACE (2934) 5.092456: buf_match_algo: none,z...@openssh.com > <mailto:z...@openssh.com>,zlib > TRACE (2934) 5.093025: hash c2s is none > TRACE (2934) 5.093598: buf_match_algo: none,z...@openssh.com > <mailto:z...@openssh.com>,zlib > TRACE (2934) 5.094179: hash s2c is none > TRACE (2934) 5.094836: leave recv_msg_kexinit > TRACE (2934) 5.095394: maybe_empty_reply_queue - no data allowed > TRACE (2934) 5.095885: enter handle_connect_fds > TRACE (2934) 5.096379: leave handle_connect_fds - end iter > TRACE (2934) 5.096902: enter set_connect_fds > TRACE (2934) 5.097611: process_packet: packet type = 30, len 42 > TRACE (2934) 5.098344: got expected packet 30 during kexinit > TRACE (2934) 5.099060: enter recv_msg_kexdh_init > TRACE (2934) 5.099589: enter send_msg_kexdh_reply > TRACE (2934) 5.234566: enter buf_put_dss_sign > TRACE (2934) 5.336603: leave buf_put_dss_sign > TRACE (2934) 5.337367: leave send_msg_kexdh_reply > TRACE (2934) 5.337903: enter send_msg_newkeys > TRACE (2934) 5.338527: enter gen_new_keys > Aiee, segfault! You should probably report this as a bug to the developer > [root@172.17.152.20 <mailto:root@172.17.152.20>: ]# > > > ---------------------------------------- from client > --------------------------------------------------------------------------- > $ ssh -v -o HostKeyAlgorithms=ssh-rsa root@172.17.152.20 > <mailto:root@172.17.152.20> > OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g 1 Mar 2016 > debug1: Reading configuration data /etc/ssh/ssh_config > debug1: /etc/ssh/ssh_config line 19: Applying options for * > debug1: Connecting to 172.17.152.20 [172.17.152.20] port 22. > debug1: Connection established. > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_rsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_rsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_dsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_dsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ecdsa type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ecdsa-cert type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ed25519 type -1 > debug1: key_load_public: No such file or directory > debug1: identity file /home//.ssh/id_ed25519-cert type -1 > debug1: Enabling compatibility mode for protocol 2.0 > debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 > debug1: Remote protocol version 2.0, remote software version dropbear_2016.74 > debug1: no match: dropbear_2016.74 > debug1: Authenticating to 172.17.152.20:22 <http://172.17.152.20:22/> as > 'root' > debug1: SSH2_MSG_KEXINIT sent > debug1: SSH2_MSG_KEXINIT received > debug1: kex: algorithm: curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org> > debug1: kex: host key algorithm: ssh-rsa > debug1: kex: server->client cipher: aes128-ctr MAC: hmac-sha2-256 > compression: none > debug1: kex: client->server cipher: aes128-ctr MAC: hmac-sha2-256 > compression: none > debug1: expecting SSH2_MSG_KEX_ECDH_REPLY > Connection closed by 172.17.152.20 port 22 > > ---------------------------------------- from dropbear > --------------------------------------------------------------------------- > [root@172.17.152.20 <mailto:root@172.17.152.20>: ]# dropbear -v -F > TRACE (3066) 0.000000: enter buf_get_rsa_priv_key > TRACE (3066) 0.000692: enter buf_get_rsa_pub_key > TRACE (3066) 0.003467: leave buf_get_rsa_pub_key: success > TRACE (3066) 0.007054: leave buf_get_rsa_priv_key > TRACE (3066) 0.007749: leave loadhostkey > TRACE (3066) 0.008958: enter buf_get_dss_pub_key > TRACE (3066) 0.011581: leave buf_get_dss_pub_key: success > TRACE (3066) 0.012362: leave loadhostkey > TRACE (3066) 0.013428: enter buf_get_ecdsa_priv_key > TRACE (3066) 0.014002: enter buf_get_ecc_raw_pubkey > TRACE (3066) 0.019249: leave buf_get_ecdsa_pub_key > TRACE (3066) 0.020103: leave loadhostkey > TRACE (3066) 0.020569: Disabling key type 2 > TRACE (3066) 0.021071: Disabling key type 3 > TRACE (3066) 0.059965: listensockets: 1 to try > TRACE (3066) 0.061012: listening on ':22' > TRACE (3066) 0.061761: enter dropbear_listen > TRACE (3066) 0.062337: dropbear_listen: all interfaces > TRACE (3066) 0.064058: bind(22) failed > TRACE (3066) 0.064837: leave dropbear_listen: success, 1 socks bound > TRACE (3066) 0.065962: set_listen_fast_open failed for socket 3: Protocol > not available > [3066] Jan 01 00:18:21 Not backgrounding > [3066] Jan 01 00:18:23 Child connection from 172.17.163.3:42554 > <http://172.17.163.3:42554/> > TRACE (3066) 2.443367: enter session_init > TRACE (3066) 2.444121: setnonblocking: 5 > TRACE (3066) 2.444770: leave setnonblocking > TRACE (3066) 2.445351: setnonblocking: 5 > TRACE (3066) 2.445970: leave setnonblocking > TRACE (3066) 2.446569: update_channel_prio > TRACE (3066) 2.447120: update_channel_prio: not any > TRACE (3066) 2.447636: Dropbear priority transitioning 10 -> 11 > TRACE (3066) 2.448406: setnonblocking: 3 > TRACE (3066) 2.449024: leave setnonblocking > TRACE (3066) 2.449518: setnonblocking: 6 > TRACE (3066) 2.450104: leave setnonblocking > TRACE (3066) 2.451526: leave session_init > TRACE (3066) 2.452468: kexinitialise() > TRACE (3066) 2.453758: DATAALLOWED=0 > TRACE (3066) 2.454296: -> KEXINIT > TRACE (3066) 2.454825: enter set_connect_fds > TRACE (3066) 2.455418: maybe_empty_reply_queue - no data allowed > TRACE (3066) 2.455931: enter handle_connect_fds > TRACE (3066) 2.456436: leave handle_connect_fds - end iter > TRACE (3066) 2.457321: empty queue dequeing > TRACE (3066) 2.458488: enter set_connect_fds > TRACE (3066) 2.459096: enter ident_readln > TRACE (3066) 2.463414: leave ident_readln: return 40 > TRACE (3066) 2.464057: remoteident: SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 > TRACE (3066) 2.464651: maybe_empty_reply_queue - no data allowed > TRACE (3066) 2.465149: enter handle_connect_fds > TRACE (3066) 2.465624: leave handle_connect_fds - end iter > TRACE (3066) 2.466161: enter set_connect_fds > TRACE (3066) 2.466961: process_packet: packet type = 20, len 1048 > TRACE (3066) 2.467688: got expected packet 20 during kexinit > TRACE (3066) 2.468301: <- KEXINIT > TRACE (3066) 2.468759: enter recv_msg_kexinit > TRACE (3066) 2.469425: buf_match_algo: curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org>,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c > TRACE (3066) 2.470150: kexguess2 1 > TRACE (3066) 2.470744: kex algo curve25519-sha...@libssh.org > <mailto:curve25519-sha...@libssh.org> > TRACE (3066) 2.471337: buf_match_algo: ssh-rsa > TRACE (3066) 2.471917: hostkey algo ssh-rsa > TRACE (3066) 2.472489: buf_match_algo: chacha20-poly1...@openssh.com > <mailto:chacha20-poly1...@openssh.com>,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com > <mailto:aes128-...@openssh.com>,aes256-...@openssh.com > <mailto:aes256-...@openssh.com>,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc > TRACE (3066) 2.473777: enc c2s is aes128-ctr > TRACE (3066) 2.474389: buf_match_algo: chacha20-poly1...@openssh.com > <mailto:chacha20-poly1...@openssh.com>,aes128-ctr,aes192-ctr,aes256-ctr,aes128-...@openssh.com > <mailto:aes128-...@openssh.com>,aes256-...@openssh.com > <mailto:aes256-...@openssh.com>,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc > TRACE (3066) 2.475073: enc s2c is aes128-ctr > TRACE (3066) 2.475668: buf_match_algo: umac-64-...@openssh.com > <mailto:umac-64-...@openssh.com>,umac-128-...@openssh.com > <mailto:umac-128-...@openssh.com>,hmac-sha2-256-...@openssh.com > <mailto:hmac-sha2-256-...@openssh.com>,hmac-sha2-512-...@openssh.com > <mailto:hmac-sha2-512-...@openssh.com>,hmac-sha1-...@openssh.com > <mailto:hmac-sha1-...@openssh.com>,umac...@openssh.com > <mailto:umac...@openssh.com>,umac-...@openssh.com > <mailto:umac-...@openssh.com>,hmac-sha2-256,hmac-sha2-512,hmac-sha1 > TRACE (3066) 2.476384: hash c2s is hmac-sha2-256 > TRACE (3066) 2.476967: buf_match_algo: umac-64-...@openssh.com > <mailto:umac-64-...@openssh.com>,umac-128-...@openssh.com > <mailto:umac-128-...@openssh.com>,hmac-sha2-256-...@openssh.com > <mailto:hmac-sha2-256-...@openssh.com>,hmac-sha2-512-...@openssh.com > <mailto:hmac-sha2-512-...@openssh.com>,hmac-sha1-...@openssh.com > <mailto:hmac-sha1-...@openssh.com>,umac...@openssh.com > <mailto:umac...@openssh.com>,umac-...@openssh.com > <mailto:umac-...@openssh.com>,hmac-sha2-256,hmac-sha2-512,hmac-sha1 > TRACE (3066) 2.477690: hash s2c is hmac-sha2-256 > TRACE (3066) 2.478301: buf_match_algo: none,z...@openssh.com > <mailto:z...@openssh.com>,zlib > TRACE (3066) 2.478884: hash c2s is none > TRACE (3066) 2.479439: buf_match_algo: none,z...@openssh.com > <mailto:z...@openssh.com>,zlib > TRACE (3066) 2.480033: hash s2c is none > TRACE (3066) 2.480702: leave recv_msg_kexinit > TRACE (3066) 2.481229: maybe_empty_reply_queue - no data allowed > TRACE (3066) 2.481743: enter handle_connect_fds > TRACE (3066) 2.482215: leave handle_connect_fds - end iter > TRACE (3066) 2.482777: enter set_connect_fds > TRACE (3066) 2.483639: process_packet: packet type = 30, len 42 > TRACE (3066) 2.484336: got expected packet 30 during kexinit > TRACE (3066) 2.484948: enter recv_msg_kexdh_init > TRACE (3066) 2.485459: enter send_msg_kexdh_reply > TRACE (3066) 2.486015: enter buf_put_rsa_pub_key > TRACE (3066) 2.492135: leave buf_put_rsa_pub_key > TRACE (3066) 2.596695: enter buf_put_rsa_pub_key > TRACE (3066) 2.602879: leave buf_put_rsa_pub_key > TRACE (3066) 2.606368: enter buf_put_rsa_sign > Aiee, segfault! You should probably report this as a bug to the developer > > > Please advise how to fix the problem in Dropbear. > > Please let me know if additional information is needed. > > Thank you, > Konstantin Lazarev.
