add the ability to query supported ciphers, MACs, key type and KEX

algorithms to ssh. Includes some refactoring of KEX and key type handling
to be table-driven; ok markus@

15 files changed, 303 insertions, 234 deletions

diff --git a/usr.bin/ssh/authfile.c b/usr.bin/ssh/authfile.c
index 65dccabe916..474b4ab8587 100644
--- a/usr.bin/ssh/authfile.c
+++ b/usr.bin/ssh/authfile.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: authfile.c,v 1.95 2013/01/08 18:49:04 markus Exp $ */
+/* $OpenBSD: authfile.c,v 1.96 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -84,7 +84,7 @@ key_private_rsa1_to_blob(Key *key, Buffer *blob, const char *passphrase,
 	u_char buf[100], *cp;
 	int i, cipher_num;
 	CipherContext ciphercontext;
-	Cipher *cipher;
+	const Cipher *cipher;
 	u_int32_t rnd;
 
 	/*
@@ -410,7 +410,7 @@ key_parse_private_rsa1(Buffer *blob, const char *passphrase, char **commentp)
 	Buffer decrypted;
 	u_char *cp;
 	CipherContext ciphercontext;
-	Cipher *cipher;
+	const Cipher *cipher;
 	Key *prv = NULL;
 	Buffer copy;
 
diff --git a/usr.bin/ssh/cipher.c b/usr.bin/ssh/cipher.c
index 3c3b123d7a7..e7ea118eaa6 100644
--- a/usr.bin/ssh/cipher.c
+++ b/usr.bin/ssh/cipher.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cipher.c,v 1.87 2013/01/26 06:11:05 djm Exp $ */
+/* $OpenBSD: cipher.c,v 1.88 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -60,7 +60,9 @@ struct Cipher {
 	u_int	discard_len;
 	u_int	cbc_mode;
 	const EVP_CIPHER	*(*evptype)(void);
-} ciphers[] = {
+};
+
+static const struct Cipher ciphers[] = {
 	{ "none",	SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null },
 	{ "des",	SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc },
 	{ "3des",	SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des },
@@ -92,6 +94,27 @@ struct Cipher {
 
 /*--*/
 
+/* Returns a comma-separated list of supported ciphers. */
+char *
+cipher_alg_list(void)
+{
+	char *ret = NULL;
+	size_t nlen, rlen = 0;
+	const Cipher *c;
+
+	for (c = ciphers; c->name != NULL; c++) {
+		if (c->number != SSH_CIPHER_SSH2)
+			continue;
+		if (ret != NULL)
+			ret[rlen++] = '\n';
+		nlen = strlen(c->name);
+		ret = xrealloc(ret, 1, rlen + nlen + 2);
+		memcpy(ret + rlen, c->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
 u_int
 cipher_blocksize(const Cipher *c)
 {
@@ -140,20 +163,20 @@ cipher_mask_ssh1(int client)
 	return mask;
 }
 
-Cipher *
+const Cipher *
 cipher_by_name(const char *name)
 {
-	Cipher *c;
+	const Cipher *c;
 	for (c = ciphers; c->name != NULL; c++)
 		if (strcmp(c->name, name) == 0)
 			return c;
 	return NULL;
 }
 
-Cipher *
+const Cipher *
 cipher_by_number(int id)
 {
-	Cipher *c;
+	const Cipher *c;
 	for (c = ciphers; c->name != NULL; c++)
 		if (c->number == id)
 			return c;
@@ -164,7 +187,7 @@ cipher_by_number(int id)
 int
 ciphers_valid(const char *names)
 {
-	Cipher *c;
+	const Cipher *c;
 	char *cipher_list, *cp;
 	char *p;
 
@@ -195,7 +218,7 @@ ciphers_valid(const char *names)
 int
 cipher_number(const char *name)
 {
-	Cipher *c;
+	const Cipher *c;
 	if (name == NULL)
 		return -1;
 	for (c = ciphers; c->name != NULL; c++)
@@ -207,12 +230,12 @@ cipher_number(const char *name)
 char *
 cipher_name(int id)
 {
-	Cipher *c = cipher_by_number(id);
+	const Cipher *c = cipher_by_number(id);
 	return (c==NULL) ? "<unknown>" : c->name;
 }
 
 void
-cipher_init(CipherContext *cc, Cipher *cipher,
+cipher_init(CipherContext *cc, const Cipher *cipher,
     const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
     int do_encrypt)
 {
@@ -344,7 +367,7 @@ cipher_cleanup(CipherContext *cc)
  */
 
 void
-cipher_set_key_string(CipherContext *cc, Cipher *cipher,
+cipher_set_key_string(CipherContext *cc, const Cipher *cipher,
     const char *passphrase, int do_encrypt)
 {
 	MD5_CTX md;
@@ -369,7 +392,7 @@ cipher_set_key_string(CipherContext *cc, Cipher *cipher,
 int
 cipher_get_keyiv_len(const CipherContext *cc)
 {
-	Cipher *c = cc->cipher;
+	const Cipher *c = cc->cipher;
 	int ivlen;
 
 	if (c->number == SSH_CIPHER_3DES)
@@ -382,7 +405,7 @@ cipher_get_keyiv_len(const CipherContext *cc)
 void
 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
 {
-	Cipher *c = cc->cipher;
+	const Cipher *c = cc->cipher;
 	int evplen;
 
 	switch (c->number) {
@@ -413,7 +436,7 @@ cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
 void
 cipher_set_keyiv(CipherContext *cc, u_char *iv)
 {
-	Cipher *c = cc->cipher;
+	const Cipher *c = cc->cipher;
 	int evplen = 0;
 
 	switch (c->number) {
@@ -445,7 +468,7 @@ cipher_set_keyiv(CipherContext *cc, u_char *iv)
 int
 cipher_get_keycontext(const CipherContext *cc, u_char *dat)
 {
-	Cipher *c = cc->cipher;
+	const Cipher *c = cc->cipher;
 	int plen = 0;
 
 	if (c->evptype == EVP_rc4) {
@@ -460,7 +483,7 @@ cipher_get_keycontext(const CipherContext *cc, u_char *dat)
 void
 cipher_set_keycontext(CipherContext *cc, u_char *dat)
 {
-	Cipher *c = cc->cipher;
+	const Cipher *c = cc->cipher;
 	int plen;
 
 	if (c->evptype == EVP_rc4) {
diff --git a/usr.bin/ssh/cipher.h b/usr.bin/ssh/cipher.h
index 8cb57c3e594..b878d50f4fc 100644
--- a/usr.bin/ssh/cipher.h
+++ b/usr.bin/ssh/cipher.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: cipher.h,v 1.39 2013/01/08 18:49:04 markus Exp $ */
+/* $OpenBSD: cipher.h,v 1.40 2013/04/19 01:06:50 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -66,21 +66,22 @@ struct CipherContext {
 	int	plaintext;
 	int	encrypt;
 	EVP_CIPHER_CTX evp;
-	Cipher *cipher;
+	const Cipher *cipher;
 };
 
 u_int	 cipher_mask_ssh1(int);
-Cipher	*cipher_by_name(const char *);
-Cipher	*cipher_by_number(int);
+const Cipher	*cipher_by_name(const char *);
+const Cipher	*cipher_by_number(int);
 int	 cipher_number(const char *);
 char	*cipher_name(int);
 int	 ciphers_valid(const char *);
-void	 cipher_init(CipherContext *, Cipher *, const u_char *, u_int,
+char	*cipher_alg_list(void);
+void	 cipher_init(CipherContext *, const Cipher *, const u_char *, u_int,
     const u_char *, u_int, int);
 void	 cipher_crypt(CipherContext *, u_char *, const u_char *,
     u_int, u_int, u_int);
 void	 cipher_cleanup(CipherContext *);
-void	 cipher_set_key_string(CipherContext *, Cipher *, const char *, int);
+void	 cipher_set_key_string(CipherContext *, const Cipher *, const char *, int);
 u_int	 cipher_blocksize(const Cipher *);
 u_int	 cipher_keylen(const Cipher *);
 u_int	 cipher_authlen(const Cipher *);
diff --git a/usr.bin/ssh/kex.c b/usr.bin/ssh/kex.c
index 023ebf099dd..185ac1a67fd 100644
--- a/usr.bin/ssh/kex.c
+++ b/usr.bin/ssh/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.88 2013/01/08 18:49:04 markus Exp $ */
+/* $OpenBSD: kex.c,v 1.89 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
@@ -51,6 +51,54 @@
 static void kex_kexinit_finish(Kex *);
 static void kex_choose_conf(Kex *);
 
+struct kexalg {
+	char *name;
+	int type;
+	int ec_nid;
+	const EVP_MD *(*mdfunc)(void);
+};
+static const struct kexalg kexalgs[] = {
+	{ KEX_DH1, KEX_DH_GRP1_SHA1, 0, EVP_sha1 },
+	{ KEX_DH14, KEX_DH_GRP14_SHA1, 0, EVP_sha1 },
+	{ KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, EVP_sha1 },
+	{ KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, EVP_sha256 },
+	{ KEX_DH1, KEX_DH_GRP1_SHA1, 0, EVP_sha1 },
+	{ KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2, NID_X9_62_prime256v1, EVP_sha256 },
+	{ KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1, EVP_sha384 },
+	{ KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1, EVP_sha512 },
+	{ NULL, -1, -1, NULL},
+};
+
+char *
+kex_alg_list(void)
+{
+	char *ret = NULL;
+	size_t nlen, rlen = 0;
+	const struct kexalg *k;
+
+	for (k = kexalgs; k->name != NULL; k++) {
+		if (ret != NULL)
+			ret[rlen++] = '\n';
+		nlen = strlen(k->name);
+		ret = xrealloc(ret, 1, rlen + nlen + 2);
+		memcpy(ret + rlen, k->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
+static const struct kexalg *
+kex_alg_by_name(const char *name)
+{
+	const struct kexalg *k;
+
+	for (k = kexalgs; k->name != NULL; k++) {
+		if (strcmp(k->name, name) == 0)
+			return k;
+	}
+	return NULL;
+}
+
 /* Validate KEX method name list */
 int
 kex_names_valid(const char *names)
@@ -62,13 +110,7 @@ kex_names_valid(const char *names)
 	s = cp = xstrdup(names);
 	for ((p = strsep(&cp, ",")); p && *p != '\0';
 	    (p = strsep(&cp, ","))) {
-	    	if (strcmp(p, KEX_DHGEX_SHA256) != 0 &&
-		    strcmp(p, KEX_DHGEX_SHA1) != 0 &&
-		    strcmp(p, KEX_DH14) != 0 &&
-		    strcmp(p, KEX_DH1) != 0 &&
-		    (strncmp(p, KEX_ECDH_SHA2_STEM,
-		    sizeof(KEX_ECDH_SHA2_STEM) - 1) != 0 ||
-		    kex_ecdh_name_to_nid(p) == -1)) {
+		if (kex_alg_by_name(p) == NULL) {
 			error("Unsupported KEX algorithm \"%.100s\"", p);
 			xfree(s);
 			return 0;
@@ -337,27 +379,16 @@ choose_comp(Comp *comp, char *client, char *server)
 static void
 choose_kex(Kex *k, char *client, char *server)
 {
+	const struct kexalg *kexalg;
+
 	k->name = match_list(client, server, NULL);
 	if (k->name == NULL)
 		fatal("Unable to negotiate a key exchange method");
-	if (strcmp(k->name, KEX_DH1) == 0) {
-		k->kex_type = KEX_DH_GRP1_SHA1;
-		k->evp_md = EVP_sha1();
-	} else if (strcmp(k->name, KEX_DH14) == 0) {
-		k->kex_type = KEX_DH_GRP14_SHA1;
-		k->evp_md = EVP_sha1();
-	} else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
-		k->kex_type = KEX_DH_GEX_SHA1;
-		k->evp_md = EVP_sha1();
-	} else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
-		k->kex_type = KEX_DH_GEX_SHA256;
-		k->evp_md = EVP_sha256();
-	} else if (strncmp(k->name, KEX_ECDH_SHA2_STEM,
-	    sizeof(KEX_ECDH_SHA2_STEM) - 1) == 0) {
-		k->kex_type = KEX_ECDH_SHA2;
-		k->evp_md = kex_ecdh_name_to_evpmd(k->name);
-	} else
-		fatal("bad kex alg %s", k->name);
+	if ((kexalg = kex_alg_by_name(k->name)) == NULL)
+		fatal("unsupported kex alg %s", k->name);
+	k->kex_type = kexalg->type;
+	k->evp_md = kexalg->mdfunc();
+	k->ec_nid = kexalg->ec_nid;
 }
 
 static void
diff --git a/usr.bin/ssh/kex.h b/usr.bin/ssh/kex.h
index 0cb2269d8c2..28e15c8520b 100644
--- a/usr.bin/ssh/kex.h
+++ b/usr.bin/ssh/kex.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.h,v 1.54 2013/01/08 18:49:04 markus Exp $ */
+/* $OpenBSD: kex.h,v 1.55 2013/04/19 01:06:50 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -37,8 +37,9 @@
 #define	KEX_DHGEX_SHA1		"diffie-hellman-group-exchange-sha1"
 #define	KEX_DHGEX_SHA256	"diffie-hellman-group-exchange-sha256"
 #define	KEX_RESUME		"resume@appgate.com"
-/* The following represents the family of ECDH methods */
-#define	KEX_ECDH_SHA2_STEM	"ecdh-sha2-"
+#define	KEX_ECDH_SHA2_NISTP256	"ecdh-sha2-nistp256"
+#define	KEX_ECDH_SHA2_NISTP384	"ecdh-sha2-nistp384"
+#define	KEX_ECDH_SHA2_NISTP521	"ecdh-sha2-nistp521"
 
 #define COMP_NONE	0
 #define COMP_ZLIB	1
@@ -83,7 +84,7 @@ typedef struct Newkeys Newkeys;
 
 struct Enc {
 	char	*name;
-	Cipher	*cipher;
+	const Cipher *cipher;
 	int	enabled;
 	u_int	key_len;
 	u_int	iv_len;
@@ -128,6 +129,7 @@ struct Kex {
 	sig_atomic_t done;
 	int	flags;
 	const EVP_MD *evp_md;
+	int	ec_nid;
 	char	*client_version_string;
 	char	*server_version_string;
 	int	(*verify_host_key)(Key *);
@@ -138,6 +140,7 @@ struct Kex {
 };
 
 int	 kex_names_valid(const char *);
+char	*kex_alg_list(void);
 
 Kex	*kex_setup(char *[PROPOSAL_MAX]);
 void	 kex_finish(Kex *);
@@ -167,9 +170,6 @@ kex_ecdh_hash(const EVP_MD *, const EC_GROUP *, char *, char *, char *, int,
     char *, int, u_char *, int, const EC_POINT *, const EC_POINT *,
     const BIGNUM *, u_char **, u_int *);
 
-int	kex_ecdh_name_to_nid(const char *);
-const EVP_MD *kex_ecdh_name_to_evpmd(const char *);
-
 void
 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]);
 
diff --git a/usr.bin/ssh/kexecdh.c b/usr.bin/ssh/kexecdh.c
index 7c1cb3e76f1..93d9b02c1ac 100644
--- a/usr.bin/ssh/kexecdh.c
+++ b/usr.bin/ssh/kexecdh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexecdh.c,v 1.3 2010/09/22 05:01:29 djm Exp $ */
+/* $OpenBSD: kexecdh.c,v 1.4 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -41,24 +41,6 @@
 #include "kex.h"
 #include "log.h"
 
-int
-kex_ecdh_name_to_nid(const char *kexname)
-{
-	if (strlen(kexname) < sizeof(KEX_ECDH_SHA2_STEM) - 1)
-		fatal("%s: kexname too short \"%s\"", __func__, kexname);
-	return key_curve_name_to_nid(kexname + sizeof(KEX_ECDH_SHA2_STEM) - 1);
-}
-
-const EVP_MD *
-kex_ecdh_name_to_evpmd(const char *kexname)
-{
-	int nid = kex_ecdh_name_to_nid(kexname);
-
-	if (nid == -1)
-		fatal("%s: unsupported ECDH curve \"%s\"", __func__, kexname);
-	return key_ec_nid_to_evpmd(nid);
-}
-
 void
 kex_ecdh_hash(
     const EVP_MD *evp_md,
diff --git a/usr.bin/ssh/kexecdhc.c b/usr.bin/ssh/kexecdhc.c
index 218768ba8ad..cb409d6c9d2 100644
--- a/usr.bin/ssh/kexecdhc.c
+++ b/usr.bin/ssh/kexecdhc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexecdhc.c,v 1.2 2010/09/22 05:01:29 djm Exp $ */
+/* $OpenBSD: kexecdhc.c,v 1.3 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -53,11 +53,8 @@ kexecdh_client(Kex *kex)
 	u_char *server_host_key_blob = NULL, *signature = NULL;
 	u_char *kbuf, *hash;
 	u_int klen, slen, sbloblen, hashlen;
-	int curve_nid;
 
-	if ((curve_nid = kex_ecdh_name_to_nid(kex->name)) == -1)
-		fatal("%s: unsupported ECDH curve \"%s\"", __func__, kex->name);
-	if ((client_key = EC_KEY_new_by_curve_name(curve_nid)) == NULL)
+	if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL)
 		fatal("%s: EC_KEY_new_by_curve_name failed", __func__);
 	if (EC_KEY_generate_key(client_key) != 1)
 		fatal("%s: EC_KEY_generate_key failed", __func__);
diff --git a/usr.bin/ssh/kexecdhs.c b/usr.bin/ssh/kexecdhs.c
index 1dee1722d9b..a624cd01eec 100644
--- a/usr.bin/ssh/kexecdhs.c
+++ b/usr.bin/ssh/kexecdhs.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexecdhs.c,v 1.2 2010/09/22 05:01:29 djm Exp $ */
+/* $OpenBSD: kexecdhs.c,v 1.3 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -55,11 +55,8 @@ kexecdh_server(Kex *kex)
 	u_char *server_host_key_blob = NULL, *signature = NULL;
 	u_char *kbuf, *hash;
 	u_int klen, slen, sbloblen, hashlen;
-	int curve_nid;
 
-	if ((curve_nid = kex_ecdh_name_to_nid(kex->name)) == -1)
-		fatal("%s: unsupported ECDH curve \"%s\"", __func__, kex->name);
-	if ((server_key = EC_KEY_new_by_curve_name(curve_nid)) == NULL)
+	if ((server_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL)
 		fatal("%s: EC_KEY_new_by_curve_name failed", __func__);
 	if (EC_KEY_generate_key(server_key) != 1)
 		fatal("%s: EC_KEY_generate_key failed", __func__);
diff --git a/usr.bin/ssh/key.c b/usr.bin/ssh/key.c
index 126bd398298..e37ae965e4b 100644
--- a/usr.bin/ssh/key.c
+++ b/usr.bin/ssh/key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: key.c,v 1.100 2013/01/17 23:00:01 djm Exp $ */
+/* $OpenBSD: key.c,v 1.101 2013/04/19 01:06:50 djm Exp $ */
 /*
  * read_bignum():
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -867,32 +867,6 @@ key_write(const Key *key, FILE *f)
 }
 
 const char *
-key_type(const Key *k)
-{
-	switch (k->type) {
-	case KEY_RSA1:
-		return "RSA1";
-	case KEY_RSA:
-		return "RSA";
-	case KEY_DSA:
-		return "DSA";
-	case KEY_ECDSA:
-		return "ECDSA";
-	case KEY_RSA_CERT_V00:
-		return "RSA-CERT-V00";
-	case KEY_DSA_CERT_V00:
-		return "DSA-CERT-V00";
-	case KEY_RSA_CERT:
-		return "RSA-CERT";
-	case KEY_DSA_CERT:
-		return "DSA-CERT";
-	case KEY_ECDSA_CERT:
-		return "ECDSA-CERT";
-	}
-	return "unknown";
-}
-
-const char *
 key_cert_type(const Key *k)
 {
 	switch (k->cert->type) {
@@ -905,46 +879,55 @@ key_cert_type(const Key *k)
 	}
 }
 
+struct keytype {
+	char *name;
+	char *shortname;
+	int type;
+	int nid;
+	int cert;
+};
+static const struct keytype keytypes[] = {
+	{ NULL, "RSA1", KEY_RSA1, 0, 0 },
+	{ "ssh-rsa", "RSA", KEY_RSA, 0, 0 },
+	{ "ssh-dss", "DSA", KEY_DSA, 0, 0 },
+	{ "ecdsa-sha2-nistp256", "ECDSA", KEY_ECDSA, NID_X9_62_prime256v1, 0 },
+	{ "ecdsa-sha2-nistp384", "ECDSA", KEY_ECDSA, NID_secp384r1, 0 },
+	{ "ecdsa-sha2-nistp521", "ECDSA", KEY_ECDSA, NID_secp521r1, 0 },
+	{ "ssh-rsa-cert-v01@openssh.com", "RSA-CERT", KEY_RSA_CERT, 0, 1 },
+	{ "ssh-dss-cert-v01@openssh.com", "DSA-CERT", KEY_DSA_CERT, 0, 1 },
+	{ "ecdsa-sha2-nistp256-cert-v01@openssh.com", "ECDSA-CERT",
+	    KEY_ECDSA_CERT, NID_X9_62_prime256v1, 1 },
+	{ "ecdsa-sha2-nistp384-cert-v01@openssh.com", "ECDSA-CERT",
+	    KEY_ECDSA_CERT, NID_secp384r1, 1 },
+	{ "ecdsa-sha2-nistp521-cert-v01@openssh.com", "ECDSA-CERT",
+	    KEY_ECDSA_CERT, NID_secp521r1, 1 },
+	{ "ssh-rsa-cert-v00@openssh.com", "RSA-CERT-V00",
+	    KEY_RSA_CERT_V00, 0, 1 },
+	{ "ssh-dss-cert-v00@openssh.com", "DSA-CERT-V00",
+	    KEY_DSA_CERT_V00, 0, 1 },
+	{ NULL, NULL, -1, -1, 0 }
+};
+
+const char *
+key_type(const Key *k)
+{
+	const struct keytype *kt;
+
+	for (kt = keytypes; kt->type != -1; kt++) {
+		if (kt->type == k->type)
+			return kt->shortname;
+	}
+	return "unknown";
+}
+
 static const char *
 key_ssh_name_from_type_nid(int type, int nid)
 {
-	switch (type) {
-	case KEY_RSA:
-		return "ssh-rsa";
-	case KEY_DSA:
-		return "ssh-dss";
-	case KEY_RSA_CERT_V00:
-		return "ssh-rsa-cert-v00@openssh.com";
-	case KEY_DSA_CERT_V00:
-		return "ssh-dss-cert-v00@openssh.com";
-	case KEY_RSA_CERT:
-		return "ssh-rsa-cert-v01@openssh.com";
-	case KEY_DSA_CERT:
-		return "ssh-dss-cert-v01@openssh.com";
-	case KEY_ECDSA:
-		switch (nid) {
-		case NID_X9_62_prime256v1:
-			return "ecdsa-sha2-nistp256";
-		case NID_secp384r1:
-			return "ecdsa-sha2-nistp384";
-		case NID_secp521r1:
-			return "ecdsa-sha2-nistp521";
-		default:
-			break;
-		}
-		break;
-	case KEY_ECDSA_CERT:
-		switch (nid) {
-		case NID_X9_62_prime256v1:
-			return "ecdsa-sha2-nistp256-cert-v01@openssh.com";
-		case NID_secp384r1:
-			return "ecdsa-sha2-nistp384-cert-v01@openssh.com";
-		case NID_secp521r1:
-			return "ecdsa-sha2-nistp521-cert-v01@openssh.com";
-		default:
-			break;
-		}
-		break;
+	const struct keytype *kt;
+
+	for (kt = keytypes; kt->type != -1; kt++) {
+		if (kt->type == type && (kt->nid == 0 || kt->nid == nid))
+			return kt->name;
 	}
 	return "ssh-unknown";
 }
@@ -962,6 +945,56 @@ key_ssh_name_plain(const Key *k)
 	    k->ecdsa_nid);
 }
 
+int
+key_type_from_name(char *name)
+{
+	const struct keytype *kt;
+
+	for (kt = keytypes; kt->type != -1; kt++) {
+		/* Only allow shortname matches for plain key types */
+		if ((kt->name != NULL && strcmp(name, kt->name) == 0) ||
+		    (!kt->cert && strcasecmp(kt->shortname, name) == 0))
+			return kt->type;
+	}
+	debug2("key_type_from_name: unknown key type '%s'", name);
+	return KEY_UNSPEC;
+}
+
+int
+key_ecdsa_nid_from_name(const char *name)
+{
+	const struct keytype *kt;
+
+	for (kt = keytypes; kt->type != -1; kt++) {
+		if (kt->type != KEY_ECDSA && kt->type != KEY_ECDSA_CERT)
+			continue;
+		if (kt->name != NULL && strcmp(name, kt->name) == 0)
+			return kt->nid;
+	}
+	debug2("%s: unknown/non-ECDSA key type '%s'", __func__, name);
+	return -1;
+}
+
+char *
+key_alg_list(void)
+{
+	char *ret = NULL;
+	size_t nlen, rlen = 0;
+	const struct keytype *kt;
+
+	for (kt = keytypes; kt->type != -1; kt++) {
+		if (kt->name == NULL)
+			continue;
+		if (ret != NULL)
+			ret[rlen++] = '\n';
+		nlen = strlen(kt->name);
+		ret = xrealloc(ret, 1, rlen + nlen + 2);
+		memcpy(ret + rlen, kt->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
 u_int
 key_size(const Key *k)
 {
@@ -1207,58 +1240,6 @@ key_from_private(const Key *k)
 }
 
 int
-key_type_from_name(char *name)
-{
-	if (strcmp(name, "rsa1") == 0) {
-		return KEY_RSA1;
-	} else if (strcmp(name, "rsa") == 0) {
-		return KEY_RSA;
-	} else if (strcmp(name, "dsa") == 0) {
-		return KEY_DSA;
-	} else if (strcmp(name, "ssh-rsa") == 0) {
-		return KEY_RSA;
-	} else if (strcmp(name, "ssh-dss") == 0) {
-		return KEY_DSA;
-	} else if (strcmp(name, "ecdsa") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp256") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp384") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp521") == 0) {
-		return KEY_ECDSA;
-	} else if (strcmp(name, "ssh-rsa-cert-v00@openssh.com") == 0) {
-		return KEY_RSA_CERT_V00;
-	} else if (strcmp(name, "ssh-dss-cert-v00@openssh.com") == 0) {
-		return KEY_DSA_CERT_V00;
-	} else if (strcmp(name, "ssh-rsa-cert-v01@openssh.com") == 0) {
-		return KEY_RSA_CERT;
-	} else if (strcmp(name, "ssh-dss-cert-v01@openssh.com") == 0) {
-		return KEY_DSA_CERT;
-	} else if (strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0)
-		return KEY_ECDSA_CERT;
-
-	debug2("key_type_from_name: unknown key type '%s'", name);
-	return KEY_UNSPEC;
-}
-
-int
-key_ecdsa_nid_from_name(const char *name)
-{
-	if (strcmp(name, "ecdsa-sha2-nistp256") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0)
-		return NID_X9_62_prime256v1;
-	if (strcmp(name, "ecdsa-sha2-nistp384") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0)
-		return NID_secp384r1;
-	if (strcmp(name, "ecdsa-sha2-nistp521") == 0 ||
-	    strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0)
-		return NID_secp521r1;
-
-	debug2("%s: unknown/non-ECDSA key type '%s'", __func__, name);
-	return -1;
-}
-
-int
 key_names_valid2(const char *names)
 {
 	char *s, *cp, *p;
diff --git a/usr.bin/ssh/key.h b/usr.bin/ssh/key.h
index 9f1b10b0835..9b24f384264 100644
--- a/usr.bin/ssh/key.h
+++ b/usr.bin/ssh/key.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: key.h,v 1.35 2013/01/17 23:00:01 djm Exp $ */
+/* $OpenBSD: key.h,v 1.36 2013/04/19 01:06:50 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -112,13 +112,14 @@ int	 key_cert_is_legacy(const Key *);
 
 int		 key_ecdsa_nid_from_name(const char *);
 int		 key_curve_name_to_nid(const char *);
-const char *	 key_curve_nid_to_name(int);
+const char	*key_curve_nid_to_name(int);
 u_int		 key_curve_nid_to_bits(int);
 int		 key_ecdsa_bits_to_nid(int);
 int		 key_ecdsa_key_to_nid(EC_KEY *);
-const EVP_MD *	 key_ec_nid_to_evpmd(int nid);
+const EVP_MD	*key_ec_nid_to_evpmd(int nid);
 int		 key_ec_validate_public(const EC_GROUP *, const EC_POINT *);
 int		 key_ec_validate_private(const EC_KEY *);
+char		*key_alg_list(void);
 
 Key		*key_from_blob(const u_char *, u_int);
 int		 key_to_blob(const Key *, u_char **, u_int *);
diff --git a/usr.bin/ssh/mac.c b/usr.bin/ssh/mac.c
index 621c6098189..111afe08b96 100644
--- a/usr.bin/ssh/mac.c
+++ b/usr.bin/ssh/mac.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mac.c,v 1.21 2012/12/11 22:51:45 sthen Exp $ */
+/* $OpenBSD: mac.c,v 1.22 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -45,7 +45,7 @@
 #define SSH_UMAC	2	/* UMAC (not integrated with OpenSSL) */
 #define SSH_UMAC128	3
 
-struct {
+struct macalg {
 	char		*name;
 	int		type;
 	const EVP_MD *	(*mdfunc)(void);
@@ -53,7 +53,9 @@ struct {
 	int		key_len;	/* just for UMAC */
 	int		len;		/* just for UMAC */
 	int		etm;		/* Encrypt-then-MAC */
-} macs[] = {
+};
+
+static const struct macalg macs[] = {
 	/* Encrypt-and-MAC (encrypt-and-authenticate) variants */
 	{ "hmac-sha1",				SSH_EVP, EVP_sha1, 0, 0, 0, 0 },
 	{ "hmac-sha1-96",			SSH_EVP, EVP_sha1, 96, 0, 0, 0 },
@@ -80,38 +82,58 @@ struct {
 	{ NULL,					0, NULL, 0, 0, 0, 0 }
 };
 
+/* Returns a comma-separated list of supported MACs. */
+char *
+mac_alg_list(void)
+{
+	char *ret = NULL;
+	size_t nlen, rlen = 0;
+	const struct macalg *m;
+
+	for (m = macs; m->name != NULL; m++) {
+		if (ret != NULL)
+			ret[rlen++] = '\n';
+		nlen = strlen(m->name);
+		ret = xrealloc(ret, 1, rlen + nlen + 2);
+		memcpy(ret + rlen, m->name, nlen + 1);
+		rlen += nlen;
+	}
+	return ret;
+}
+
 static void
-mac_setup_by_id(Mac *mac, int which)
+mac_setup_by_alg(Mac *mac, const struct macalg *macalg)
 {
 	int evp_len;
-	mac->type = macs[which].type;
+
+	mac->type = macalg->type;
 	if (mac->type == SSH_EVP) {
-		mac->evp_md = (*macs[which].mdfunc)();
+		mac->evp_md = macalg->mdfunc();
 		if ((evp_len = EVP_MD_size(mac->evp_md)) <= 0)
 			fatal("mac %s len %d", mac->name, evp_len);
 		mac->key_len = mac->mac_len = (u_int)evp_len;
 	} else {
-		mac->mac_len = macs[which].len / 8;
-		mac->key_len = macs[which].key_len / 8;
+		mac->mac_len = macalg->len / 8;
+		mac->key_len = macalg->key_len / 8;
 		mac->umac_ctx = NULL;
 	}
-	if (macs[which].truncatebits != 0)
-		mac->mac_len = macs[which].truncatebits / 8;
-	mac->etm = macs[which].etm;
+	if (macalg->truncatebits != 0)
+		mac->mac_len = macalg->truncatebits / 8;
+	mac->etm = macalg->etm;
 }
 
 int
 mac_setup(Mac *mac, char *name)
 {
-	int i;
-
-	for (i = 0; macs[i].name; i++) {
-		if (strcmp(name, macs[i].name) == 0) {
-			if (mac != NULL)
-				mac_setup_by_id(mac, i);
-			debug2("mac_setup: found %s", name);
-			return (0);
-		}
+	const struct macalg *m;
+
+	for (m = macs; m->name != NULL; m++) {
+		if (strcmp(name, m->name) != 0)
+			continue;
+		if (mac != NULL)
+			mac_setup_by_alg(mac, m);
+		debug2("mac_setup: found %s", name);
+		return (0);
 	}
 	debug2("mac_setup: unknown %s", name);
 	return (-1);
diff --git a/usr.bin/ssh/mac.h b/usr.bin/ssh/mac.h
index 39f564dd300..260798ab3b0 100644
--- a/usr.bin/ssh/mac.h
+++ b/usr.bin/ssh/mac.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: mac.h,v 1.6 2007/06/07 19:37:34 pvalchev Exp $ */
+/* $OpenBSD: mac.h,v 1.7 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -24,6 +24,7 @@
  */
 
 int	 mac_valid(const char *);
+char	*mac_alg_list(void);
 int	 mac_setup(Mac *, char *);
 int	 mac_init(Mac *);
 u_char	*mac_compute(Mac *, u_int32_t, u_char *, int);
diff --git a/usr.bin/ssh/packet.c b/usr.bin/ssh/packet.c
index 032485d537b..b8fb80ba5d2 100644
--- a/usr.bin/ssh/packet.c
+++ b/usr.bin/ssh/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.182 2013/04/11 02:27:50 djm Exp $ */
+/* $OpenBSD: packet.c,v 1.183 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -211,7 +211,7 @@ alloc_session_state(void)
 void
 packet_set_connection(int fd_in, int fd_out)
 {
-	Cipher *none = cipher_by_name("none");
+	const Cipher *none = cipher_by_name("none");
 
 	if (none == NULL)
 		fatal("packet_set_connection: cannot load cipher 'none'");
@@ -536,7 +536,7 @@ packet_start_compression(int level)
 void
 packet_set_encryption_key(const u_char *key, u_int keylen, int number)
 {
-	Cipher *cipher = cipher_by_number(number);
+	const Cipher *cipher = cipher_by_number(number);
 
 	if (cipher == NULL)
 		fatal("packet_set_encryption_key: unknown cipher number %d", number);
diff --git a/usr.bin/ssh/ssh.1 b/usr.bin/ssh/ssh.1
index d77494b8326..dc7af48642e 100644
--- a/usr.bin/ssh/ssh.1
+++ b/usr.bin/ssh/ssh.1
@@ -33,8 +33,8 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.\" $OpenBSD: ssh.1,v 1.331 2013/04/07 02:10:33 dtucker Exp $
-.Dd $Mdocdate: April 7 2013 $
+.\" $OpenBSD: ssh.1,v 1.332 2013/04/19 01:06:50 djm Exp $
+.Dd $Mdocdate: April 19 2013 $
 .Dt SSH 1
 .Os
 .Sh NAME
@@ -65,6 +65,8 @@
 .Oo Ar user Ns @ Oc Ns Ar hostname
 .Op Ar command
 .Ek
+.Nm
+.Fl Q Ar protocol_feature
 .Sh DESCRIPTION
 .Nm
 (SSH client) is a program for logging into a remote machine and for
@@ -487,6 +489,21 @@ For full details of the options listed below, and their possible values, see
 Port to connect to on the remote host.
 This can be specified on a
 per-host basis in the configuration file.
+.It Fl Q Ar protocol_feature
+Queries
+.Nm
+for the algorithms supported for the specified version 2
+.Ar protocol_feature .
+The queriable features are:
+.Dq cipher
+(supported symmetric ciphers),
+.Dq MAC
+(supported message integrity codes),
+.Dq KEX
+(key exchange algorithms),
+.Dq key
+(key types).
+Protocol features are treated case-insensitively.
 .It Fl q
 Quiet mode.
 Causes most warning and diagnostic messages to be suppressed.
diff --git a/usr.bin/ssh/ssh.c b/usr.bin/ssh/ssh.c
index 022f7d351f7..74862804bdd 100644
--- a/usr.bin/ssh/ssh.c
+++ b/usr.bin/ssh/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.375 2013/04/07 02:10:33 dtucker Exp $ */
+/* $OpenBSD: ssh.c,v 1.376 2013/04/19 01:06:50 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -298,7 +298,7 @@ main(int ac, char **av)
 
  again:
 	while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
-	    "ACD:E:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
+	    "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 		switch (opt) {
 		case '1':
 			options.protocol = SSH_PROTO_1;
@@ -360,6 +360,22 @@ main(int ac, char **av)
 		case 'P':	/* deprecated */
 			options.use_privileged_port = 0;
 			break;
+		case 'Q':	/* deprecated */
+			cp = NULL;
+			if (strcasecmp(optarg, "cipher") == 0)
+				cp = cipher_alg_list();
+			else if (strcasecmp(optarg, "mac") == 0)
+				cp = mac_alg_list();
+			else if (strcasecmp(optarg, "kex") == 0)
+				cp = kex_alg_list();
+			else if (strcasecmp(optarg, "key") == 0)
+				cp = key_alg_list();
+			if (cp == NULL)
+				fatal("Unsupported query \"%s\"", optarg);
+			printf("%s\n", cp);
+			free(cp);
+			exit(0);
+			break;
 		case 'a':
 			options.forward_agent = 0;
 			break;