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upstream commit 

Turn off DSA by default; add HostKeyAlgorithms to the
 server and PubkeyAcceptedKeyTypes to the client side, so it still can be
 tested or turned back on; feedback and ok djm@

Upstream-ID: 8450a9e6d83f80c9bfed864ff061dfc9323cec21
This commit is contained in:
markus@openbsd.org 2015-07-10 06:21:53 +00:00 committed by Damien Miller
parent 16db0a7ee9
commit 3a1638dda1
12 changed files with 173 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
clientloop.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: clientloop.c,v 1.274 2015/07/01 02:26:31 djm Exp $ */ /* $OpenBSD: clientloop.c,v 1.275 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Author: Tatu Ylonen <ylo@cs.hut.fi> * Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -100,6 +100,7 @@
#include "key.h" #include "key.h"
#include "cipher.h" #include "cipher.h"
#include "kex.h" #include "kex.h"
#include "myproposal.h"
#include "log.h" #include "log.h"
#include "misc.h" #include "misc.h"
#include "readconf.h" #include "readconf.h"
@ -2362,10 +2363,11 @@ client_input_hostkeys(void)
debug3("%s: received %s key %s", __func__, debug3("%s: received %s key %s", __func__,
sshkey_type(key), fp); sshkey_type(key), fp);
free(fp); free(fp);
/* Check that the key is accepted in HostkeyAlgorithms */ /* Check that the key is accepted in HostkeyAlgorithms */
if (options.hostkeyalgorithms != NULL && if (match_pattern_list(sshkey_ssh_name(key),
match_pattern_list(sshkey_ssh_name(key), options.hostkeyalgorithms ? options.hostkeyalgorithms :
options.hostkeyalgorithms, 0) != 1) { KEX_DEFAULT_PK_ALG, 0) != 1) {
debug3("%s: %s key not permitted by HostkeyAlgorithms", debug3("%s: %s key not permitted by HostkeyAlgorithms",
__func__, sshkey_ssh_name(key)); __func__, sshkey_ssh_name(key));
continue; continue;

6
myproposal.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: myproposal.h,v 1.46 2015/07/03 03:47:00 djm Exp $ */ /* $OpenBSD: myproposal.h,v 1.47 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved.
@ -99,11 +99,9 @@
HOSTKEY_ECDSA_CERT_METHODS \ HOSTKEY_ECDSA_CERT_METHODS \
"ssh-ed25519-cert-v01@openssh.com," \ "ssh-ed25519-cert-v01@openssh.com," \
"ssh-rsa-cert-v01@openssh.com," \ "ssh-rsa-cert-v01@openssh.com," \
"ssh-dss-cert-v01@openssh.com," \
HOSTKEY_ECDSA_METHODS \ HOSTKEY_ECDSA_METHODS \
"ssh-ed25519," \ "ssh-ed25519," \
"ssh-rsa," \ "ssh-rsa" \
"ssh-dss"
/* the actual algorithms */ /* the actual algorithms */

37
readconf.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: readconf.c,v 1.237 2015/06/26 05:13:20 djm Exp $ */ /* $OpenBSD: readconf.c,v 1.238 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Author: Tatu Ylonen <ylo@cs.hut.fi> * Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -157,6 +157,7 @@ typedef enum {
oCanonicalizeFallbackLocal, oCanonicalizePermittedCNAMEs, oCanonicalizeFallbackLocal, oCanonicalizePermittedCNAMEs,
oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys, oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys,
oFingerprintHash, oUpdateHostkeys, oHostbasedKeyTypes, oFingerprintHash, oUpdateHostkeys, oHostbasedKeyTypes,
oPubkeyAcceptedKeyTypes,
oIgnoredUnknownOption, oDeprecated, oUnsupported oIgnoredUnknownOption, oDeprecated, oUnsupported
} OpCodes; } OpCodes;
@ -275,6 +276,7 @@ static struct {
{ "fingerprinthash", oFingerprintHash }, { "fingerprinthash", oFingerprintHash },
{ "updatehostkeys", oUpdateHostkeys }, { "updatehostkeys", oUpdateHostkeys },
{ "hostbasedkeytypes", oHostbasedKeyTypes }, { "hostbasedkeytypes", oHostbasedKeyTypes },
{ "pubkeyacceptedkeytypes", oPubkeyAcceptedKeyTypes },
{ "ignoreunknown", oIgnoreUnknown }, { "ignoreunknown", oIgnoreUnknown },
{ NULL, oBadOption } { NULL, oBadOption }
@ -1115,14 +1117,17 @@ parse_int:
break; break;
case oHostKeyAlgorithms: case oHostKeyAlgorithms:
charptr = &options->hostkeyalgorithms;
parse_keytypes:
arg = strdelim(&s); arg = strdelim(&s);
if (!arg || *arg == '\0') if (!arg || *arg == '\0')
fatal("%.200s line %d: Missing argument.", filename, linenum); fatal("%.200s line %d: Missing argument.",
filename, linenum);
if (!sshkey_names_valid2(arg, 1)) if (!sshkey_names_valid2(arg, 1))
fatal("%.200s line %d: Bad protocol 2 host key algorithms '%s'.", fatal("%s line %d: Bad key types '%s'.",
filename, linenum, arg ? arg : "<NONE>"); filename, linenum, arg ? arg : "<NONE>");
if (*activep && options->hostkeyalgorithms == NULL) if (*activep && *charptr == NULL)
options->hostkeyalgorithms = xstrdup(arg); *charptr = xstrdup(arg);
break; break;
case oProtocol: case oProtocol:
@ -1485,16 +1490,11 @@ parse_int:
case oHostbasedKeyTypes: case oHostbasedKeyTypes:
charptr = &options->hostbased_key_types; charptr = &options->hostbased_key_types;
arg = strdelim(&s); goto parse_keytypes;
if (!arg || *arg == '\0')
fatal("%.200s line %d: Missing argument.", case oPubkeyAcceptedKeyTypes:
filename, linenum); charptr = &options->pubkey_key_types;
if (!sshkey_names_valid2(arg, 1)) goto parse_keytypes;
fatal("%s line %d: Bad key types '%s'.",
filename, linenum, arg ? arg : "<NONE>");
if (*activep && *charptr == NULL)
*charptr = xstrdup(arg);
break;
case oDeprecated: case oDeprecated:
debug("%s line %d: Deprecated option \"%s\"", debug("%s line %d: Deprecated option \"%s\"",
@ -1676,6 +1676,7 @@ initialize_options(Options * options)
options->fingerprint_hash = -1; options->fingerprint_hash = -1;
options->update_hostkeys = -1; options->update_hostkeys = -1;
options->hostbased_key_types = NULL; options->hostbased_key_types = NULL;
options->pubkey_key_types = NULL;
} }
/* /*
@ -1858,7 +1859,9 @@ fill_default_options(Options * options)
if (options->update_hostkeys == -1) if (options->update_hostkeys == -1)
options->update_hostkeys = 0; options->update_hostkeys = 0;
if (options->hostbased_key_types == NULL) if (options->hostbased_key_types == NULL)
options->hostbased_key_types = xstrdup("*"); options->hostbased_key_types = xstrdup(KEX_DEFAULT_PK_ALG);
if (options->pubkey_key_types == NULL)
options->pubkey_key_types = xstrdup(KEX_DEFAULT_PK_ALG);
#define CLEAR_ON_NONE(v) \ #define CLEAR_ON_NONE(v) \
do { \ do { \

5
readconf.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: readconf.h,v 1.109 2015/02/16 22:13:32 djm Exp $ */ /* $OpenBSD: readconf.h,v 1.110 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Author: Tatu Ylonen <ylo@cs.hut.fi> * Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -150,7 +150,8 @@ typedef struct {
int update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */ int update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */
char *hostbased_key_types; char *hostbased_key_types;
char *pubkey_key_types;
char *ignored_unknown; /* Pattern list of unknown tokens to ignore */ char *ignored_unknown; /* Pattern list of unknown tokens to ignore */
} Options; } Options;

5
scp.1
View File

@ -8,9 +8,9 @@
.\" .\"
.\" Created: Sun May 7 00:14:37 1995 ylo .\" Created: Sun May 7 00:14:37 1995 ylo
.\" .\"
.\" $OpenBSD: scp.1,v 1.66 2015/01/30 11:43:14 djm Exp $ .\" $OpenBSD: scp.1,v 1.67 2015/07/10 06:21:53 markus Exp $
.\" .\"
.Dd $Mdocdate: January 30 2015 $ .Dd $Mdocdate: July 10 2015 $
.Dt SCP 1 .Dt SCP 1
.Os .Os
.Sh NAME .Sh NAME
@ -170,6 +170,7 @@ For full details of the options listed below, and their possible values, see
.It PreferredAuthentications .It PreferredAuthentications
.It Protocol .It Protocol
.It ProxyCommand .It ProxyCommand
.It PubkeyAcceptedKeyTypes
.It PubkeyAuthentication .It PubkeyAuthentication
.It RekeyLimit .It RekeyLimit
.It RhostsRSAAuthentication .It RhostsRSAAuthentication

17
servconf.c
View File

@ -1,5 +1,5 @@
/* $OpenBSD: servconf.c,v 1.275 2015/07/01 02:39:06 djm Exp $ */ /* $OpenBSD: servconf.c,v 1.276 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved * All rights reserved
@ -108,6 +108,7 @@ initialize_server_options(ServerOptions *options)
options->hostbased_authentication = -1; options->hostbased_authentication = -1;
options->hostbased_uses_name_from_packet_only = -1; options->hostbased_uses_name_from_packet_only = -1;
options->hostbased_key_types = NULL; options->hostbased_key_types = NULL;
options->hostkeyalgorithms = NULL;
options->rsa_authentication = -1; options->rsa_authentication = -1;
options->pubkey_authentication = -1; options->pubkey_authentication = -1;
options->pubkey_key_types = NULL; options->pubkey_key_types = NULL;
@ -259,13 +260,15 @@ fill_default_server_options(ServerOptions *options)
if (options->hostbased_uses_name_from_packet_only == -1) if (options->hostbased_uses_name_from_packet_only == -1)
options->hostbased_uses_name_from_packet_only = 0; options->hostbased_uses_name_from_packet_only = 0;
if (options->hostbased_key_types == NULL) if (options->hostbased_key_types == NULL)
options->hostbased_key_types = xstrdup("*"); options->hostbased_key_types = xstrdup(KEX_DEFAULT_PK_ALG);
if (options->hostkeyalgorithms == NULL)
options->hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG);
if (options->rsa_authentication == -1) if (options->rsa_authentication == -1)
options->rsa_authentication = 1; options->rsa_authentication = 1;
if (options->pubkey_authentication == -1) if (options->pubkey_authentication == -1)
options->pubkey_authentication = 1; options->pubkey_authentication = 1;
if (options->pubkey_key_types == NULL) if (options->pubkey_key_types == NULL)
options->pubkey_key_types = xstrdup("*"); options->pubkey_key_types = xstrdup(KEX_DEFAULT_PK_ALG);
if (options->kerberos_authentication == -1) if (options->kerberos_authentication == -1)
options->kerberos_authentication = 0; options->kerberos_authentication = 0;
if (options->kerberos_or_local_passwd == -1) if (options->kerberos_or_local_passwd == -1)
@ -400,6 +403,7 @@ typedef enum {
sXAuthLocation, sSubsystem, sMaxStartups, sMaxAuthTries, sMaxSessions, sXAuthLocation, sSubsystem, sMaxStartups, sMaxAuthTries, sMaxSessions,
sBanner, sUseDNS, sHostbasedAuthentication, sBanner, sUseDNS, sHostbasedAuthentication,
sHostbasedUsesNameFromPacketOnly, sHostbasedAcceptedKeyTypes, sHostbasedUsesNameFromPacketOnly, sHostbasedAcceptedKeyTypes,
sHostKeyAlgorithms,
sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile, sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor, sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
sAcceptEnv, sPermitTunnel, sAcceptEnv, sPermitTunnel,
@ -450,6 +454,7 @@ static struct {
{ "hostbasedauthentication", sHostbasedAuthentication, SSHCFG_ALL }, { "hostbasedauthentication", sHostbasedAuthentication, SSHCFG_ALL },
{ "hostbasedusesnamefrompacketonly", sHostbasedUsesNameFromPacketOnly, SSHCFG_ALL }, { "hostbasedusesnamefrompacketonly", sHostbasedUsesNameFromPacketOnly, SSHCFG_ALL },
{ "hostbasedacceptedkeytypes", sHostbasedAcceptedKeyTypes, SSHCFG_ALL }, { "hostbasedacceptedkeytypes", sHostbasedAcceptedKeyTypes, SSHCFG_ALL },
{ "hostkeyalgorithms", sHostKeyAlgorithms, SSHCFG_GLOBAL },
{ "rsaauthentication", sRSAAuthentication, SSHCFG_ALL }, { "rsaauthentication", sRSAAuthentication, SSHCFG_ALL },
{ "pubkeyauthentication", sPubkeyAuthentication, SSHCFG_ALL }, { "pubkeyauthentication", sPubkeyAuthentication, SSHCFG_ALL },
{ "pubkeyacceptedkeytypes", sPubkeyAcceptedKeyTypes, SSHCFG_ALL }, { "pubkeyacceptedkeytypes", sPubkeyAcceptedKeyTypes, SSHCFG_ALL },
@ -1183,6 +1188,10 @@ process_server_config_line(ServerOptions *options, char *line,
*charptr = xstrdup(arg); *charptr = xstrdup(arg);
break; break;
case sHostKeyAlgorithms:
charptr = &options->hostkeyalgorithms;
goto parse_keytypes;
case sRSAAuthentication: case sRSAAuthentication:
intptr = &options->rsa_authentication; intptr = &options->rsa_authentication;
goto parse_flag; goto parse_flag;
@ -2280,6 +2289,8 @@ dump_config(ServerOptions *o)
o->kex_algorithms ? o->kex_algorithms : KEX_SERVER_KEX); o->kex_algorithms ? o->kex_algorithms : KEX_SERVER_KEX);
dump_cfg_string(sHostbasedAcceptedKeyTypes, o->hostbased_key_types ? dump_cfg_string(sHostbasedAcceptedKeyTypes, o->hostbased_key_types ?
o->hostbased_key_types : KEX_DEFAULT_PK_ALG); o->hostbased_key_types : KEX_DEFAULT_PK_ALG);
dump_cfg_string(sHostKeyAlgorithms, o->hostkeyalgorithms ?
o->hostkeyalgorithms : KEX_DEFAULT_PK_ALG);
dump_cfg_string(sPubkeyAcceptedKeyTypes, o->pubkey_key_types ? dump_cfg_string(sPubkeyAcceptedKeyTypes, o->pubkey_key_types ?
o->pubkey_key_types : KEX_DEFAULT_PK_ALG); o->pubkey_key_types : KEX_DEFAULT_PK_ALG);

3
servconf.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: servconf.h,v 1.119 2015/05/22 03:50:02 djm Exp $ */ /* $OpenBSD: servconf.h,v 1.120 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Author: Tatu Ylonen <ylo@cs.hut.fi> * Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -102,6 +102,7 @@ typedef struct {
int hostbased_authentication; /* If true, permit ssh2 hostbased auth */ int hostbased_authentication; /* If true, permit ssh2 hostbased auth */
int hostbased_uses_name_from_packet_only; /* experimental */ int hostbased_uses_name_from_packet_only; /* experimental */
char *hostbased_key_types; /* Key types allowed for hostbased */ char *hostbased_key_types; /* Key types allowed for hostbased */
char *hostkeyalgorithms; /* SSH2 server key types */
int rsa_authentication; /* If true, permit RSA authentication. */ int rsa_authentication; /* If true, permit RSA authentication. */
int pubkey_authentication; /* If true, permit ssh2 pubkey authentication. */ int pubkey_authentication; /* If true, permit ssh2 pubkey authentication. */
char *pubkey_key_types; /* Key types allowed for public key */ char *pubkey_key_types; /* Key types allowed for public key */

5
ssh.1
View File

@ -33,8 +33,8 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: ssh.1,v 1.358 2015/05/22 05:28:45 djm Exp $ .\" $OpenBSD: ssh.1,v 1.359 2015/07/10 06:21:53 markus Exp $
.Dd $Mdocdate: May 22 2015 $ .Dd $Mdocdate: July 10 2015 $
.Dt SSH 1 .Dt SSH 1
.Os .Os
.Sh NAME .Sh NAME
@ -470,6 +470,7 @@ For full details of the options listed below, and their possible values, see
.It Protocol .It Protocol
.It ProxyCommand .It ProxyCommand
.It ProxyUseFdpass .It ProxyUseFdpass
.It PubkeyAcceptedKeyTypes
.It PubkeyAuthentication .It PubkeyAuthentication
.It RekeyLimit .It RekeyLimit
.It RemoteForward .It RemoteForward

42
ssh_config.5
View File

@ -33,8 +33,8 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: ssh_config.5,v 1.212 2015/07/03 03:47:00 djm Exp $ .\" $OpenBSD: ssh_config.5,v 1.213 2015/07/10 06:21:53 markus Exp $
.Dd $Mdocdate: July 3 2015 $ .Dd $Mdocdate: July 10 2015 $
.Dt SSH_CONFIG 5 .Dt SSH_CONFIG 5
.Os .Os
.Sh NAME .Sh NAME
@ -781,9 +781,17 @@ is similar to
.It Cm HostbasedKeyTypes .It Cm HostbasedKeyTypes
Specifies the key types that will be used for hostbased authentication Specifies the key types that will be used for hostbased authentication
as a comma-separated pattern list. as a comma-separated pattern list.
The default The default for this option is:
.Dq * .Bd -literal -offset 3n
will allow all key types. ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa
.Ed
.Pp
The The
.Fl Q .Fl Q
option of option of
@ -798,10 +806,9 @@ ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com, ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com, ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com, ssh-rsa-cert-v01@openssh.com,
ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521, ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa,ssh-dss ssh-ed25519,ssh-rsa
.Ed .Ed
.Pp .Pp
If hostkeys are known for the destination host then this default is modified If hostkeys are known for the destination host then this default is modified
@ -1206,6 +1213,25 @@ will pass a connected file descriptor back to
instead of continuing to execute and pass data. instead of continuing to execute and pass data.
The default is The default is
.Dq no . .Dq no .
.It Cm PubkeyAcceptedKeyTypes
Specifies the key types that will be used for public key authentication
as a comma-separated pattern list.
The default for this option is:
.Bd -literal -offset 3n
ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa
.Ed
.Pp
The
.Fl Q
option of
.Xr ssh 1
may be used to list supported key types.
.It Cm PubkeyAuthentication .It Cm PubkeyAuthentication
Specifies whether to try public key authentication. Specifies whether to try public key authentication.
The argument to this keyword must be The argument to this keyword must be

39
sshconnect2.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: sshconnect2.c,v 1.224 2015/05/04 06:10:48 djm Exp $ */ /* $OpenBSD: sshconnect2.c,v 1.225 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Damien Miller. All rights reserved. * Copyright (c) 2008 Damien Miller. All rights reserved.
@ -190,6 +190,8 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
compat_pkalg_proposal(options.hostkeyalgorithms); compat_pkalg_proposal(options.hostkeyalgorithms);
else { else {
/* Enforce default */
options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG);
/* Prefer algorithms that we already have keys for */ /* Prefer algorithms that we already have keys for */
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
compat_pkalg_proposal( compat_pkalg_proposal(
@ -1315,6 +1317,26 @@ pubkey_cleanup(Authctxt *authctxt)
} }
} }
static int
try_identity(Identity *id)
{
if (!id->key)
return (0);
if (match_pattern_list(sshkey_ssh_name(id->key),
options.pubkey_key_types, 0) != 1) {
debug("Skipping %s key %s for not in PubkeyAcceptedKeyTypes",
sshkey_ssh_name(id->key), id->filename);
return (0);
}
if (key_type_plain(id->key->type) == KEY_RSA &&
(datafellows & SSH_BUG_RSASIGMD5) != 0) {
debug("Skipped %s key %s for RSA/MD5 server",
key_type(id->key), id->filename);
return (0);
}
return (id->key->type != KEY_RSA1);
}
int int
userauth_pubkey(Authctxt *authctxt) userauth_pubkey(Authctxt *authctxt)
{ {
@ -1333,11 +1355,7 @@ userauth_pubkey(Authctxt *authctxt)
* private key instead * private key instead
*/ */
if (id->key != NULL) { if (id->key != NULL) {
if (key_type_plain(id->key->type) == KEY_RSA && if (try_identity(id)) {
(datafellows & SSH_BUG_RSASIGMD5) != 0) {
debug("Skipped %s key %s for RSA/MD5 server",
key_type(id->key), id->filename);
} else if (id->key->type != KEY_RSA1) {
debug("Offering %s public key: %s", debug("Offering %s public key: %s",
key_type(id->key), id->filename); key_type(id->key), id->filename);
sent = send_pubkey_test(authctxt, id); sent = send_pubkey_test(authctxt, id);
@ -1347,13 +1365,8 @@ userauth_pubkey(Authctxt *authctxt)
id->key = load_identity_file(id->filename, id->key = load_identity_file(id->filename,
id->userprovided); id->userprovided);
if (id->key != NULL) { if (id->key != NULL) {
id->isprivate = 1; if (try_identity(id)) {
if (key_type_plain(id->key->type) == KEY_RSA && id->isprivate = 1;
(datafellows & SSH_BUG_RSASIGMD5) != 0) {
debug("Skipped %s key %s for RSA/MD5 "
"server", key_type(id->key),
id->filename);
} else {
sent = sign_and_send_pubkey( sent = sign_and_send_pubkey(
authctxt, id); authctxt, id);
} }

10
sshd.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: sshd.c,v 1.453 2015/07/03 03:49:45 djm Exp $ */ /* $OpenBSD: sshd.c,v 1.454 2015/07/10 06:21:53 markus Exp $ */
/* /*
* Author: Tatu Ylonen <ylo@cs.hut.fi> * Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -95,6 +95,7 @@
#include "log.h" #include "log.h"
#include "buffer.h" #include "buffer.h"
#include "misc.h" #include "misc.h"
#include "match.h"
#include "servconf.h" #include "servconf.h"
#include "uidswap.h" #include "uidswap.h"
#include "compat.h" #include "compat.h"
@ -799,6 +800,13 @@ list_hostkey_types(void)
key = sensitive_data.host_pubkeys[i]; key = sensitive_data.host_pubkeys[i];
if (key == NULL) if (key == NULL)
continue; continue;
/* Check that the key is accepted in HostkeyAlgorithms */
if (match_pattern_list(sshkey_ssh_name(key),
options.hostkeyalgorithms, 0) != 1) {
debug3("%s: %s key not permitted by HostkeyAlgorithms",
__func__, sshkey_ssh_name(key));
continue;
}
switch (key->type) { switch (key->type) {
case KEY_RSA: case KEY_RSA:
case KEY_DSA: case KEY_DSA:

60
sshd_config.5
View File

@ -33,8 +33,8 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: sshd_config.5,v 1.205 2015/07/03 03:49:45 djm Exp $ .\" $OpenBSD: sshd_config.5,v 1.206 2015/07/10 06:21:53 markus Exp $
.Dd $Mdocdate: July 3 2015 $ .Dd $Mdocdate: July 10 2015 $
.Dt SSHD_CONFIG 5 .Dt SSHD_CONFIG 5
.Os .Os
.Sh NAME .Sh NAME
@ -640,9 +640,17 @@ The default is
.It Cm HostbasedAcceptedKeyTypes .It Cm HostbasedAcceptedKeyTypes
Specifies the key types that will be accepted for hostbased authentication Specifies the key types that will be accepted for hostbased authentication
as a comma-separated pattern list. as a comma-separated pattern list.
The default The default for this option is:
.Dq * .Bd -literal -offset 3n
will allow all key types. ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa
.Ed
.Pp
The The
.Fl Q .Fl Q
option of option of
@ -694,9 +702,15 @@ for protocol version 1, and
and and
.Pa /etc/ssh/ssh_host_rsa_key .Pa /etc/ssh/ssh_host_rsa_key
for protocol version 2. for protocol version 2.
.Pp
Note that Note that
.Xr sshd 8 .Xr sshd 8
will refuse to use a file if it is group/world-accessible. will refuse to use a file if it is group/world-accessible
and that the
.Cm HostKeyAlgorithms
option restricts which of the keys are actually used by
.Xr sshd 8 .
.Pp
It is possible to have multiple host key files. It is possible to have multiple host key files.
.Dq rsa1 .Dq rsa1
keys are used for version 1 and keys are used for version 1 and
@ -718,6 +732,26 @@ If
is specified, the location of the socket will be read from the is specified, the location of the socket will be read from the
.Ev SSH_AUTH_SOCK .Ev SSH_AUTH_SOCK
environment variable. environment variable.
.It Cm HostKeyAlgorithms
Specifies the protocol version 2 host key algorithms
that the server offers.
The default for this option is:
.Bd -literal -offset 3n
ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa
.Ed
.Pp
The list of available key types may also be obtained using the
.Fl Q
option of
.Xr ssh 1
with an argument of
.Dq key .
.It Cm IgnoreRhosts .It Cm IgnoreRhosts
Specifies that Specifies that
.Pa .rhosts .Pa .rhosts
@ -1279,9 +1313,17 @@ is identical to
.It Cm PubkeyAcceptedKeyTypes .It Cm PubkeyAcceptedKeyTypes
Specifies the key types that will be accepted for public key authentication Specifies the key types that will be accepted for public key authentication
as a comma-separated pattern list. as a comma-separated pattern list.
The default The default for this option is:
.Dq * .Bd -literal -offset 3n
will allow all key types. ecdsa-sha2-nistp256-cert-v01@openssh.com,
ecdsa-sha2-nistp384-cert-v01@openssh.com,
ecdsa-sha2-nistp521-cert-v01@openssh.com,
ssh-ed25519-cert-v01@openssh.com,
ssh-rsa-cert-v01@openssh.com,
ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
ssh-ed25519,ssh-rsa
.Ed
.Pp
The The
.Fl Q .Fl Q
option of option of