From d1aaf71d0b7e1d59b88a119a95e3d1ef22792acc Mon Sep 17 00:00:00 2001 From: simon Date: Wed, 22 Dec 2004 10:53:58 +0000 Subject: [PATCH] Support diffie-hellman-group14-sha1 group exchange. Tested against locally built OpenSSH 3.9, and seems to work fine. git-svn-id: svn://svn.tartarus.org/sgt/putty@5018 cda61777-01e9-0310-a592-d414129be87e --- ssh.c | 19 +++++++++++-------- ssh.h | 17 ++++++++++------- sshdh.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++----------------- 3 files changed, 69 insertions(+), 32 deletions(-) diff --git a/ssh.c b/ssh.c index 0377e9a8..a6fba8b8 100644 --- a/ssh.c +++ b/ssh.c @@ -104,7 +104,7 @@ * Packet type contexts, so that ssh2_pkt_type can correctly decode * the ambiguous type numbers back into the correct type strings. */ -#define SSH2_PKTCTX_DHGROUP1 0x0001 +#define SSH2_PKTCTX_DHGROUP 0x0001 #define SSH2_PKTCTX_DHGEX 0x0002 #define SSH2_PKTCTX_PUBLICKEY 0x0010 #define SSH2_PKTCTX_PASSWORD 0x0020 @@ -222,8 +222,8 @@ static char *ssh2_pkt_type(int pkt_ctx, int type) translate(SSH2_MSG_SERVICE_ACCEPT); translate(SSH2_MSG_KEXINIT); translate(SSH2_MSG_NEWKEYS); - translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1); - translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1); + translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP); + translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP); translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX); translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX); translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX); @@ -362,7 +362,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman_gex, - &ssh_diffiehellman + &ssh_diffiehellman_group14, + &ssh_diffiehellman_group1, }; const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; @@ -4650,7 +4651,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, * If we're doing Diffie-Hellman group exchange, start by * requesting a group. */ - if (ssh->kex == &ssh_diffiehellman_gex) { + if (!ssh->kex->pdata) { logevent("Doing Diffie-Hellman group exchange"); ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX; /* @@ -4673,14 +4674,16 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, bombout(("unable to read mp-ints from incoming group packet")); crStop(0); } - ssh->kex_ctx = dh_setup_group(s->p, s->g); + ssh->kex_ctx = dh_setup_gex(s->p, s->g); s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; } else { - ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1; - ssh->kex_ctx = dh_setup_group1(); + ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP; + ssh->kex_ctx = dh_setup_group(ssh->kex); s->kex_init_value = SSH2_MSG_KEXDH_INIT; s->kex_reply_value = SSH2_MSG_KEXDH_REPLY; + logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"", + ssh->kex->groupname); } logevent("Doing Diffie-Hellman key exchange"); diff --git a/ssh.h b/ssh.h index 687ce6ab..2685090b 100644 --- a/ssh.h +++ b/ssh.h @@ -177,11 +177,13 @@ struct ssh_kex { /* * Plugging in another KEX algorithm requires structural chaos, * so it's hard to abstract them into nice little structures - * like this. Hence, for the moment, this is just a - * placeholder. I claim justification in the fact that OpenSSH - * does this too :-) + * like this. Fortunately, all our KEXes are basically + * Diffie-Hellman at the moment, so in this structure I simply + * parametrise the DH exchange a bit. */ - char *name; + char *name, *groupname; + const unsigned char *pdata, *gdata;/* NULL means use group exchange */ + int plen, glen; }; struct ssh_signkey { @@ -231,7 +233,8 @@ extern const struct ssh2_ciphers ssh2_3des; extern const struct ssh2_ciphers ssh2_des; extern const struct ssh2_ciphers ssh2_aes; extern const struct ssh2_ciphers ssh2_blowfish; -extern const struct ssh_kex ssh_diffiehellman; +extern const struct ssh_kex ssh_diffiehellman_group1; +extern const struct ssh_kex ssh_diffiehellman_group14; extern const struct ssh_kex ssh_diffiehellman_gex; extern const struct ssh_signkey ssh_dss; extern const struct ssh_signkey ssh_rsa; @@ -336,8 +339,8 @@ char *bignum_decimal(Bignum x); void diagbn(char *prefix, Bignum md); #endif -void *dh_setup_group1(void); -void *dh_setup_group(Bignum pval, Bignum gval); +void *dh_setup_group(const struct ssh_kex *kex); +void *dh_setup_gex(Bignum pval, Bignum gval); void dh_cleanup(void *); Bignum dh_create_e(void *, int nbits); Bignum dh_find_K(void *, Bignum f); diff --git a/sshdh.c b/sshdh.c index af7eaf82..898ff640 100644 --- a/sshdh.c +++ b/sshdh.c @@ -1,17 +1,9 @@ #include "ssh.h" -const struct ssh_kex ssh_diffiehellman = { - "diffie-hellman-group1-sha1" -}; - -const struct ssh_kex ssh_diffiehellman_gex = { - "diffie-hellman-group-exchange-sha1" -}; - /* - * The prime p used in the key exchange. + * The primes used in the group1 and group14 key exchange. */ -static const unsigned char P[] = { +static const unsigned char P1[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2, 0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1, 0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6, @@ -24,12 +16,51 @@ static const unsigned char P[] = { 0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE6, 0x53, 0x81, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; +static const unsigned char P14[] = { + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2, + 0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1, + 0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6, + 0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD, + 0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D, + 0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45, + 0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9, + 0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED, + 0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11, + 0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D, + 0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36, + 0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, 0xFD, 0x24, 0xCF, 0x5F, + 0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, 0xF3, 0x56, + 0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D, + 0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08, + 0xCA, 0x18, 0x21, 0x7C, 0x32, 0x90, 0x5E, 0x46, 0x2E, 0x36, 0xCE, 0x3B, + 0xE3, 0x9E, 0x77, 0x2C, 0x18, 0x0E, 0x86, 0x03, 0x9B, 0x27, 0x83, 0xA2, + 0xEC, 0x07, 0xA2, 0x8F, 0xB5, 0xC5, 0x5D, 0xF0, 0x6F, 0x4C, 0x52, 0xC9, + 0xDE, 0x2B, 0xCB, 0xF6, 0x95, 0x58, 0x17, 0x18, 0x39, 0x95, 0x49, 0x7C, + 0xEA, 0x95, 0x6A, 0xE5, 0x15, 0xD2, 0x26, 0x18, 0x98, 0xFA, 0x05, 0x10, + 0x15, 0x72, 0x8E, 0x5A, 0x8A, 0xAC, 0xAA, 0x68, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF +}; /* - * The generator g = 2. + * The generator g = 2 (used for both group1 and group14). */ static const unsigned char G[] = { 2 }; +const struct ssh_kex ssh_diffiehellman_group1 = { + "diffie-hellman-group1-sha1", "group1", + P1, G, lenof(P1), lenof(G) +}; + +const struct ssh_kex ssh_diffiehellman_group14 = { + "diffie-hellman-group14-sha1", "group14", + P14, G, lenof(P14), lenof(G) +}; + +const struct ssh_kex ssh_diffiehellman_gex = { + "diffie-hellman-group-exchange-sha1", NULL, + NULL, NULL, 0, 0 +}; + /* * Variables. */ @@ -48,21 +79,21 @@ static void dh_init(struct dh_ctx *ctx) } /* - * Initialise DH for the standard group1. + * Initialise DH for a standard group. */ -void *dh_setup_group1(void) +void *dh_setup_group(const struct ssh_kex *kex) { struct dh_ctx *ctx = snew(struct dh_ctx); - ctx->p = bignum_from_bytes(P, sizeof(P)); - ctx->g = bignum_from_bytes(G, sizeof(G)); + ctx->p = bignum_from_bytes(kex->pdata, kex->plen); + ctx->g = bignum_from_bytes(kex->gdata, kex->glen); dh_init(ctx); return ctx; } /* - * Initialise DH for an alternative group. + * Initialise DH for a server-supplied group. */ -void *dh_setup_group(Bignum pval, Bignum gval) +void *dh_setup_gex(Bignum pval, Bignum gval) { struct dh_ctx *ctx = snew(struct dh_ctx); ctx->p = copybn(pval); -- 2.11.0