From e557416818242c2e8b14ec03d321740fd83619e4 Mon Sep 17 00:00:00 2001 From: simon Date: Tue, 5 Sep 2000 14:28:17 +0000 Subject: [PATCH] SSH 2 support, phase 1, debugging. Currently does Diffie-Hellman and gets the same results as the server, which is a pretty good start. git-svn-id: svn://svn.tartarus.org/sgt/putty@569 cda61777-01e9-0310-a592-d414129be87e --- Makefile | 10 +- ssh.c | 802 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------- ssh.h | 60 +++++ sshblowf.c | 4 +- sshbn.c | 239 ++++++++++++++++++ sshdes.c | 8 +- sshdh.c | 115 +++++++++ sshdss.c | 5 + sshrsa.c | 202 +--------------- sshsha.c | 185 +++++++++++++- 10 files changed, 1325 insertions(+), 305 deletions(-) create mode 100644 sshbn.c create mode 100644 sshdh.c create mode 100644 sshdss.c diff --git a/Makefile b/Makefile index dd7b0672..dc671ffa 100644 --- a/Makefile +++ b/Makefile @@ -57,7 +57,8 @@ SOBJS = scp.$(OBJ) windlg.$(OBJ) ssh.$(OBJ) be_none.$(OBJ) MOBJS = misc.$(OBJ) version.$(OBJ) ##-- objects putty pscp OBJS1 = sshcrc.$(OBJ) sshdes.$(OBJ) sshmd5.$(OBJ) sshrsa.$(OBJ) sshrand.$(OBJ) -OBJS2 = sshsha.$(OBJ) sshblowf.$(OBJ) noise.$(OBJ) +OBJS2 = sshsha.$(OBJ) sshblowf.$(OBJ) noise.$(OBJ) sshdh.$(OBJ) sshdss.$(OBJ) +OBJS3 = sshbn.$(OBJ) ##-- resources putty PRESRC = win_res.$(RES) ##-- resources puttytel @@ -78,7 +79,7 @@ LIBS2 = wsock32.lib comctl32.lib comdlg32.lib all: putty.exe puttytel.exe pscp.exe -putty.exe: $(GOBJS1) $(GOBJS2) $(POBJS) $(MOBJS) $(OBJS1) $(OBJS2) $(PRESRC) putty.rsp +putty.exe: $(GOBJS1) $(GOBJS2) $(POBJS) $(MOBJS) $(OBJS1) $(OBJS2) $(OBJS3) $(PRESRC) putty.rsp link $(LFLAGS) -out:putty.exe @putty.rsp puttytel.exe: $(GOBJS1) $(GOBJS2) $(TOBJS) $(MOBJS) $(TRESRC) puttytel.rsp @@ -95,6 +96,7 @@ putty.rsp: makefile echo $(MOBJS) >> putty.rsp echo $(OBJS1) >> putty.rsp echo $(OBJS2) >> putty.rsp + echo $(OBJS3) >> putty.rsp echo $(PRESRC) >> putty.rsp echo $(LIBS1) >> putty.rsp echo $(LIBS2) >> putty.rsp @@ -115,6 +117,7 @@ pscp.rsp: makefile echo $(MOBJS) >> pscp.rsp echo $(OBJS1) >> pscp.rsp echo $(OBJS2) >> pscp.rsp + echo $(OBJS3) >> pscp.rsp echo $(SRESRC) >> pscp.rsp echo $(LIBS1) >> pscp.rsp echo $(LIBS2) >> pscp.rsp @@ -138,6 +141,9 @@ sshrsa.$(OBJ): sshrsa.c ssh.h sshsha.$(OBJ): sshsha.c ssh.h sshrand.$(OBJ): sshrand.c ssh.h sshblowf.$(OBJ): sshblowf.c ssh.h +sshdh.$(OBJ): sshdh.c ssh.h +sshdss.$(OBJ): sshdss.c ssh.h +sshbn.$(OBJ): sshbn.c ssh.h scp.$(OBJ): scp.c putty.h scp.h version.$(OBJ): version.c be_all.$(OBJ): be_all.c diff --git a/ssh.c b/ssh.c index 65f0075c..ae41a80e 100644 --- a/ssh.c +++ b/ssh.c @@ -19,30 +19,41 @@ if (IS_SCP && (scp_flags & SCP_VERBOSE) != 0) \ fprintf(stderr, "%s\n", s); } -#define SSH_MSG_DISCONNECT 1 -#define SSH_SMSG_PUBLIC_KEY 2 -#define SSH_CMSG_SESSION_KEY 3 -#define SSH_CMSG_USER 4 -#define SSH_CMSG_AUTH_PASSWORD 9 -#define SSH_CMSG_REQUEST_PTY 10 -#define SSH_CMSG_WINDOW_SIZE 11 -#define SSH_CMSG_EXEC_SHELL 12 -#define SSH_CMSG_EXEC_CMD 13 -#define SSH_SMSG_SUCCESS 14 -#define SSH_SMSG_FAILURE 15 -#define SSH_CMSG_STDIN_DATA 16 -#define SSH_SMSG_STDOUT_DATA 17 -#define SSH_SMSG_STDERR_DATA 18 -#define SSH_CMSG_EOF 19 -#define SSH_SMSG_EXIT_STATUS 20 -#define SSH_CMSG_EXIT_CONFIRMATION 33 -#define SSH_MSG_IGNORE 32 -#define SSH_MSG_DEBUG 36 -#define SSH_CMSG_AUTH_TIS 39 -#define SSH_SMSG_AUTH_TIS_CHALLENGE 40 -#define SSH_CMSG_AUTH_TIS_RESPONSE 41 - -#define SSH_AUTH_TIS 5 +#define SSH1_MSG_DISCONNECT 1 +#define SSH1_SMSG_PUBLIC_KEY 2 +#define SSH1_CMSG_SESSION_KEY 3 +#define SSH1_CMSG_USER 4 +#define SSH1_CMSG_AUTH_PASSWORD 9 +#define SSH1_CMSG_REQUEST_PTY 10 +#define SSH1_CMSG_WINDOW_SIZE 11 +#define SSH1_CMSG_EXEC_SHELL 12 +#define SSH1_CMSG_EXEC_CMD 13 +#define SSH1_SMSG_SUCCESS 14 +#define SSH1_SMSG_FAILURE 15 +#define SSH1_CMSG_STDIN_DATA 16 +#define SSH1_SMSG_STDOUT_DATA 17 +#define SSH1_SMSG_STDERR_DATA 18 +#define SSH1_CMSG_EOF 19 +#define SSH1_SMSG_EXIT_STATUS 20 +#define SSH1_CMSG_EXIT_CONFIRMATION 33 +#define SSH1_MSG_IGNORE 32 +#define SSH1_MSG_DEBUG 36 +#define SSH1_CMSG_AUTH_TIS 39 +#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 +#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 + +#define SSH1_AUTH_TIS 5 + +#define SSH2_MSG_DISCONNECT 1 +#define SSH2_MSG_IGNORE 2 +#define SSH2_MSG_UNIMPLEMENTED 3 +#define SSH2_MSG_DEBUG 4 +#define SSH2_MSG_SERVICE_REQUEST 5 +#define SSH2_MSG_SERVICE_ACCEPT 6 +#define SSH2_MSG_KEXINIT 20 +#define SSH2_MSG_NEWKEYS 21 +#define SSH2_MSG_KEXDH_INIT 30 +#define SSH2_MSG_KEXDH_REPLY 31 #define GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ @@ -76,10 +87,48 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR }; #define crStopV do{ crLine = 0; return; }while(0) #define crWaitUntil(c) do { crReturn(0); } while (!(c)) +extern struct ssh_cipher ssh_3des; +extern struct ssh_cipher ssh_des; +extern struct ssh_cipher ssh_blowfish; + +/* for ssh 2; we miss out single-DES because it isn't supported */ +struct ssh_cipher *ciphers[] = { &ssh_3des, &ssh_blowfish }; + +extern struct ssh_kex ssh_diffiehellman; +struct ssh_kex *kex_algs[] = { &ssh_diffiehellman }; + +extern struct ssh_hostkey ssh_dss; +struct ssh_hostkey *hostkey_algs[] = { &ssh_dss }; + +extern struct ssh_mac ssh_sha1; + +SHA_State exhash; + +static void nullmac_sesskey(unsigned char *key, int len) { } +static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { } +static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; } +struct ssh_mac ssh_mac_none = { + nullmac_sesskey, nullmac_generate, nullmac_verify, "none", 0 +}; +struct ssh_mac *macs[] = { &ssh_sha1, &ssh_mac_none }; + +struct ssh_compress ssh_comp_none = { + "none" +}; +struct ssh_compress *compressions[] = { &ssh_comp_none }; + static SOCKET s = INVALID_SOCKET; static unsigned char session_key[32]; static struct ssh_cipher *cipher = NULL; +static struct ssh_cipher *cscipher = NULL; +static struct ssh_cipher *sccipher = NULL; +static struct ssh_mac *csmac = NULL; +static struct ssh_mac *scmac = NULL; +static struct ssh_compress *cscomp = NULL; +static struct ssh_compress *sccomp = NULL; +static struct ssh_kex *kex = NULL; +static struct ssh_hostkey *hostkey = NULL; int scp_flags = 0; int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL; @@ -137,25 +186,29 @@ struct Packet { int type; unsigned char *data; unsigned char *body; + long savedpos; long maxlen; }; static struct Packet pktin = { 0, 0, NULL, NULL, 0 }; static struct Packet pktout = { 0, 0, NULL, NULL, 0 }; -static void ssh_protocol(unsigned char *in, int inlen, int ispkt); +static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt); +static void ssh1_protocol(unsigned char *in, int inlen, int ispkt); +static void ssh2_protocol(unsigned char *in, int inlen, int ispkt); static void ssh_size(void); +static int (*s_rdpkt)(unsigned char **data, int *datalen); /* * Collect incoming data in the incoming packet buffer. - * Decihper and verify the packet when it is completely read. - * Drop SSH_MSG_DEBUG and SSH_MSG_IGNORE packets. + * Decipher and verify the packet when it is completely read. + * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets. * Update the *data and *datalen variables. * Return the additional nr of bytes needed, or 0 when * a complete packet is available. */ -static int s_rdpkt(unsigned char **data, int *datalen) +static int ssh1_rdpkt(unsigned char **data, int *datalen) { static long len, pad, biglen, to_read; static unsigned long realcrc, gotcrc; @@ -188,15 +241,8 @@ next_packet: if (pktin.maxlen < biglen) { pktin.maxlen = biglen; -#ifdef MSCRYPTOAPI - /* Allocate enough buffer space for extra block - * for MS CryptEncrypt() */ - pktin.data = (pktin.data == NULL ? malloc(biglen+8) : - realloc(pktin.data, biglen+8)); -#else - pktin.data = (pktin.data == NULL ? malloc(biglen) : - realloc(pktin.data, biglen)); -#endif + pktin.data = (pktin.data == NULL ? malloc(biglen+APIEXTRA) : + realloc(pktin.data, biglen+APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } @@ -229,16 +275,16 @@ next_packet: fatalbox("Incorrect CRC received on packet"); } - if (pktin.type == SSH_SMSG_STDOUT_DATA || - pktin.type == SSH_SMSG_STDERR_DATA || - pktin.type == SSH_MSG_DEBUG || - pktin.type == SSH_SMSG_AUTH_TIS_CHALLENGE) { + if (pktin.type == SSH1_SMSG_STDOUT_DATA || + pktin.type == SSH1_SMSG_STDERR_DATA || + pktin.type == SSH1_MSG_DEBUG || + pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE) { long strlen = GET_32BIT(pktin.body); if (strlen + 4 != pktin.length) fatalbox("Received data packet with bogus string length"); } - if (pktin.type == SSH_MSG_DEBUG) { + if (pktin.type == SSH1_MSG_DEBUG) { /* log debug message */ char buf[80]; int strlen = GET_32BIT(pktin.body); @@ -248,7 +294,7 @@ next_packet: buf[8+strlen] = '\0'; logevent(buf); goto next_packet; - } else if (pktin.type == SSH_MSG_IGNORE) { + } else if (pktin.type == SSH1_MSG_IGNORE) { /* do nothing */ goto next_packet; } @@ -256,6 +302,118 @@ next_packet: crFinish(0); } +static int ssh2_rdpkt(unsigned char **data, int *datalen) +{ + static long len, pad, payload, packetlen, maclen; + static int i; + static int cipherblk; + static unsigned long incoming_sequence = 0; + + crBegin; + +next_packet: + + pktin.type = 0; + pktin.length = 0; + + if (cipher) + cipherblk = cipher->blksize; + else + cipherblk = 8; + if (cipherblk < 8) + cipherblk = 8; + + if (pktin.maxlen < cipherblk) { + pktin.maxlen = cipherblk; + pktin.data = (pktin.data == NULL ? malloc(cipherblk+APIEXTRA) : + realloc(pktin.data, cipherblk+APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); + } + + /* + * Acquire and decrypt the first block of the packet. This will + * contain the length and padding details. + */ + for (i = len = 0; i < cipherblk; i++) { + while ((*datalen) == 0) + crReturn(cipherblk-i); + pktin.data[i] = *(*data)++; + (*datalen)--; + } +#ifdef FWHACK + if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */ + /* FIXME */ + } +#endif + if (sccipher) + sccipher->decrypt(pktin.data, cipherblk); + + /* + * Now get the length and padding figures. + */ + len = GET_32BIT(pktin.data); + pad = pktin.data[4]; + + /* + * This enables us to deduce the payload length. + */ + payload = len - pad - 1; + + pktin.length = payload + 5; + + /* + * So now we can work out the total packet length. + */ + packetlen = len + 4; + maclen = scmac ? scmac->len : 0; + + /* + * Adjust memory allocation if packet is too big. + */ + if (pktin.maxlen < packetlen) { + pktin.maxlen = packetlen; + pktin.data = (pktin.data == NULL ? malloc(packetlen+APIEXTRA) : + realloc(pktin.data, packetlen+APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); + } + + /* + * Read and decrypt the remainder of the packet. + */ + for (i = cipherblk; i < packetlen + maclen; i++) { + while ((*datalen) == 0) + crReturn(packetlen + maclen - i); + pktin.data[i] = *(*data)++; + (*datalen)--; + } + /* Decrypt everything _except_ the MAC. */ + if (sccipher) + sccipher->decrypt(pktin.data + cipherblk, packetlen - cipherblk); + + /* + * Check the MAC. + */ + if (scmac && !scmac->verify(pktin.data, incoming_sequence++, len+4)) + fatalbox("Incorrect MAC received on packet"); + + pktin.savedpos = 6; + pktin.type = pktin.data[5]; +#if 0 + debug(("Got packet len=%d pad=%d\r\n", len, pad)); + for (i = 0; i < payload; i++) + debug((" %02x", (unsigned char)pktin.data[i])); + debug(("\r\n")); +#endif + + /* + * FIXME: handle IGNORE and DEBUG messages. + */ + + crFinish(0); +} + static void ssh_gotdata(unsigned char *data, int datalen) { while (datalen > 0) { @@ -509,6 +667,24 @@ static int ssh_versioncmp(char *a, char *b) { return 0; } + +/* + * Utility routine for putting an SSH-protocol `string' into a SHA + * state. + */ +#include +void sha_string(SHA_State *s, void *str, int len) { + unsigned char lenblk[4]; +static FILE *fp; + PUT_32BIT(lenblk, len); +if (!fp) fp = fopen("h:\\statham\\windows\\putty\\data","wb"); +fwrite(lenblk, 4, 1, fp); + SHA_Bytes(s, lenblk, 4); +fwrite(str, len, 1, fp); +fflush(fp); + SHA_Bytes(s, str, len); +} + static int do_ssh_init(void) { char c, *vsp; char version[10]; @@ -554,19 +730,45 @@ static int do_ssh_init(void) { vlog[strcspn(vlog, "\r\n")] = '\0'; logevent(vlog); - sprintf(vstring, "SSH-%s-PuTTY\n", - (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5")); - sprintf(vlog, "We claim version: %s", vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; - logevent(vlog); - s_write(vstring, strlen(vstring)); + if (ssh_versioncmp(version, "1.99") >= 0) { + /* + * This is a v2 server. Begin v2 protocol. + */ + char *verstring = "SSH-2.0-PuTTY"; + SHA_Init(&exhash); + /* + * Hash our version string and their version string. + */ + sha_string(&exhash, verstring, strlen(verstring)); + sha_string(&exhash, vstring, strcspn(vstring, "\r\n")); + sprintf(vstring, "%s\n", verstring); + sprintf(vlog, "We claim version: %s", verstring); + logevent(vlog); + logevent("Using SSH protocol version 2"); + s_write(vstring, strlen(vstring)); + ssh_protocol = ssh2_protocol; + s_rdpkt = ssh2_rdpkt; + } else { + /* + * This is a v1 server. Begin v1 protocol. + */ + sprintf(vstring, "SSH-%s-PuTTY\n", + (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5")); + sprintf(vlog, "We claim version: %s", vstring); + vlog[strcspn(vlog, "\r\n")] = '\0'; + logevent(vlog); + logevent("Using SSH protocol version 1"); + s_write(vstring, strlen(vstring)); + ssh_protocol = ssh1_protocol; + s_rdpkt = ssh1_rdpkt; + } return 1; } /* * Handle the key exchange and user authentication phases. */ -static int do_ssh_login(unsigned char *in, int inlen, int ispkt) +static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) { int i, j, len; unsigned char session_id[16]; @@ -577,15 +779,11 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) static unsigned long supported_ciphers_mask, supported_auths_mask; int cipher_type; - extern struct ssh_cipher ssh_3des; - extern struct ssh_cipher ssh_des; - extern struct ssh_cipher ssh_blowfish; - crBegin; if (!ispkt) crWaitUntil(ispkt); - if (pktin.type != SSH_SMSG_PUBLIC_KEY) + if (pktin.type != SSH1_SMSG_PUBLIC_KEY) fatalbox("Public key packet not received"); logevent("Received public keys"); @@ -677,7 +875,7 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break; } - send_packet(SSH_CMSG_SESSION_KEY, + send_packet(SSH1_CMSG_SESSION_KEY, PKT_CHAR, cipher_type, PKT_DATA, cookie, 8, PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF, @@ -696,7 +894,7 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) crWaitUntil(ispkt); - if (pktin.type != SSH_SMSG_SUCCESS) + if (pktin.type != SSH1_SMSG_SUCCESS) fatalbox("Encryption not successfully enabled"); logevent("Successfully started encryption"); @@ -752,7 +950,7 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) } } - send_packet(SSH_CMSG_USER, PKT_STR, username, PKT_END); + send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); { char userlog[20+sizeof(username)]; sprintf(userlog, "Sent username \"%s\"", username); @@ -762,7 +960,7 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) crWaitUntil(ispkt); - while (pktin.type == SSH_SMSG_FAILURE) { + while (pktin.type == SSH1_SMSG_FAILURE) { static char password[100]; static int pos; static char c; @@ -772,7 +970,7 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) * Show password prompt, having first obtained it via a TIS * exchange if we're doing TIS authentication. */ - pwpkt_type = SSH_CMSG_AUTH_PASSWORD; + pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; if (IS_SCP) { char prompt[200]; @@ -790,14 +988,14 @@ static int do_ssh_login(unsigned char *in, int inlen, int ispkt) } } else { - if (pktin.type == SSH_SMSG_FAILURE && + if (pktin.type == SSH1_SMSG_FAILURE && cfg.try_tis_auth && - (supported_auths_mask & (1<> 8) & 0xFF; + p[i*2+2] = (b[n-i] ) & 0xFF; + } + i = 0; + while (p[i] == 0 && (p[i+1] & 0x80) == 0) + i++; + memmove(p, p+i, n*2+1-i); + *len = n*2+1-i; + return p; +} +void ssh2_pkt_addmp(Bignum b) { + unsigned char *p; + int len; + p = ssh2_mpint_fmt(b, &len); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(p, len); + free(p); +} +void ssh2_pkt_send(void) { + int cipherblk, maclen, padding, i; + unsigned long outgoing_sequence = 0; + + /* + * Add padding. At least four bytes, and must also bring total + * length (minus MAC) up to a multiple of the block size. + */ + cipherblk = cipher ? cipher->blksize : 8; /* block size */ + cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ + padding = 4; + padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk; + pktout.data[4] = padding; + for (i = 0; i < padding; i++) + pktout.data[pktout.length + i] = random_byte(); + PUT_32BIT(pktout.data, pktout.length + padding - 4); + if (csmac) + csmac->generate(pktout.data, outgoing_sequence++, + pktout.length + padding); + if (cscipher) + cscipher->encrypt(pktout.data, pktout.length + padding); + maclen = csmac ? csmac->len : 0; +#if 0 + debug(("Sending packet len=%d\r\n", pktout.length+padding+maclen)); + for (i = 0; i < pktout.length+padding+maclen; i++) + debug((" %02x", (unsigned char)pktout.data[i])); + debug(("\r\n")); +#endif + s_write(pktout.data, pktout.length + padding + maclen); +} + +void sha_mpint(SHA_State *s, Bignum b) { + unsigned char *p; + int len; + p = ssh2_mpint_fmt(b, &len); + sha_string(s, p, len); + free(p); +} + +/* + * SSH2 packet decode functions. + */ +void ssh2_pkt_getstring(char **p, int *length) { + *p = NULL; + if (pktin.length - pktin.savedpos < 4) + return; + *length = GET_32BIT(pktin.data+pktin.savedpos); + pktin.savedpos += 4; + if (pktin.length - pktin.savedpos < *length) + return; + *p = pktin.data+pktin.savedpos; + pktin.savedpos += *length; +} +Bignum ssh2_pkt_getmp(void) { + char *p; + int i, j, length; + Bignum b; + + ssh2_pkt_getstring(&p, &length); + if (!p) + return NULL; + if (p[0] & 0x80) + fatalbox("internal error: Can't handle negative mpints"); + b = newbn((length+1)/2); + for (i = 0; i < length; i++) { + j = length - 1 - i; + if (j & 1) + b[j/2+1] |= ((unsigned char)p[i]) << 8; + else + b[j/2+1] |= ((unsigned char)p[i]); + } + return b; +} + +void bndebug(char *string, Bignum b) { + unsigned char *p; + int i, len; + p = ssh2_mpint_fmt(b, &len); + debug(("%s", string)); + for (i = 0; i < len; i++) + debug((" %02x", p[i])); + debug(("\r\n")); + free(p); +} + +/* + * Utility routine for decoding comma-separated strings in KEXINIT. + */ +int in_commasep_string(char *needle, char *haystack, int haylen) { + int needlen = strlen(needle); + while (1) { + /* + * Is it at the start of the string? + */ + if (haylen >= needlen && /* haystack is long enough */ + !memcmp(needle, haystack, needlen) && /* initial match */ + (haylen == needlen || haystack[needlen] == ',') + /* either , or EOS follows */ + ) + return 1; + /* + * If not, search for the next comma and resume after that. + * If no comma found, terminate. + */ + while (haylen > 0 && *haystack != ',') + haylen--, haystack++; + if (haylen == 0) + return 0; + haylen--, haystack++; /* skip over comma itself */ + } +} + +/* + * Handle the SSH2 key exchange phase. + */ +static int do_ssh2_kex(unsigned char *in, int inlen, int ispkt) +{ + static int i, len; + static char *str; + static Bignum e, f, K; + static struct ssh_cipher *cscipher_tobe = NULL; + static struct ssh_cipher *sccipher_tobe = NULL; + static struct ssh_mac *csmac_tobe = NULL; + static struct ssh_mac *scmac_tobe = NULL; + static struct ssh_compress *cscomp_tobe = NULL; + static struct ssh_compress *sccomp_tobe = NULL; + static char *hostkeydata, *sigdata; + static int hostkeylen, siglen; + static unsigned char exchange_hash[20]; + + crBegin; + + /* + * Construct and send our key exchange packet. + */ + ssh2_pkt_init(SSH2_MSG_KEXINIT); + for (i = 0; i < 16; i++) + ssh2_pkt_addbyte((unsigned char)random_byte()); + /* List key exchange algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(kex_algs); i++) { + ssh2_pkt_addstring_str(kex_algs[i]->name); + if (i < lenof(kex_algs)-1) + ssh2_pkt_addstring_str(","); + } + /* List server host key algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(hostkey_algs); i++) { + ssh2_pkt_addstring_str(hostkey_algs[i]->name); + if (i < lenof(hostkey_algs)-1) + ssh2_pkt_addstring_str(","); + } + /* List client->server encryption algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(ciphers); i++) { + ssh2_pkt_addstring_str(ciphers[i]->name); + if (i < lenof(ciphers)-1) + ssh2_pkt_addstring_str(","); + } + /* List server->client encryption algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(ciphers); i++) { + ssh2_pkt_addstring_str(ciphers[i]->name); + if (i < lenof(ciphers)-1) + ssh2_pkt_addstring_str(","); + } + /* List client->server MAC algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(macs); i++) { + ssh2_pkt_addstring_str(macs[i]->name); + if (i < lenof(macs)-1) + ssh2_pkt_addstring_str(","); + } + /* List server->client MAC algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(macs); i++) { + ssh2_pkt_addstring_str(macs[i]->name); + if (i < lenof(macs)-1) + ssh2_pkt_addstring_str(","); + } + /* List client->server compression algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(compressions); i++) { + ssh2_pkt_addstring_str(compressions[i]->name); + if (i < lenof(compressions)-1) + ssh2_pkt_addstring_str(","); + } + /* List server->client compression algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(compressions); i++) { + ssh2_pkt_addstring_str(compressions[i]->name); + if (i < lenof(compressions)-1) + ssh2_pkt_addstring_str(","); + } + /* List client->server languages. Empty list. */ + ssh2_pkt_addstring_start(); + /* List server->client languages. Empty list. */ + ssh2_pkt_addstring_start(); + /* First KEX packet does _not_ follow, because we're not that brave. */ + ssh2_pkt_addbool(FALSE); + /* Reserved. */ + ssh2_pkt_adduint32(0); + sha_string(&exhash, pktout.data+5, pktout.length-5); + ssh2_pkt_send(); + + if (!ispkt) crWaitUntil(ispkt); + sha_string(&exhash, pktin.data+5, pktin.length-5); + + /* + * Now examine the other side's KEXINIT to see what we're up + * to. + */ + if (pktin.type != SSH2_MSG_KEXINIT) + fatalbox("expected key exchange packet from server"); + kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL; + csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL; + pktin.savedpos += 16; /* skip garbage cookie */ + ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */ + for (i = 0; i < lenof(kex_algs); i++) { + if (in_commasep_string(kex_algs[i]->name, str, len)) { + kex = kex_algs[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* host key algorithms */ + for (i = 0; i < lenof(hostkey_algs); i++) { + if (in_commasep_string(hostkey_algs[i]->name, str, len)) { + hostkey = hostkey_algs[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* client->server cipher */ + for (i = 0; i < lenof(ciphers); i++) { + if (in_commasep_string(ciphers[i]->name, str, len)) { + cscipher_tobe = ciphers[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* server->client cipher */ + for (i = 0; i < lenof(ciphers); i++) { + if (in_commasep_string(ciphers[i]->name, str, len)) { + sccipher_tobe = ciphers[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* client->server mac */ + for (i = 0; i < lenof(macs); i++) { + if (in_commasep_string(macs[i]->name, str, len)) { + csmac_tobe = macs[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* server->client mac */ + for (i = 0; i < lenof(macs); i++) { + if (in_commasep_string(macs[i]->name, str, len)) { + scmac_tobe = macs[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* client->server compression */ + for (i = 0; i < lenof(compressions); i++) { + if (in_commasep_string(compressions[i]->name, str, len)) { + cscomp_tobe = compressions[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* server->client compression */ + for (i = 0; i < lenof(compressions); i++) { + if (in_commasep_string(compressions[i]->name, str, len)) { + sccomp_tobe = compressions[i]; + break; + } + } + debug(("key exchange is %s\r\n", kex ? kex->name : NULL)); + debug(("host key alg is %s\r\n", hostkey ? hostkey->name : NULL)); + debug(("cscipher alg is %s\r\n", cscipher_tobe ? cscipher_tobe->name : NULL)); + debug(("sccipher alg is %s\r\n", sccipher_tobe ? sccipher_tobe->name : NULL)); + debug(("csmac alg is %s\r\n", csmac_tobe ? csmac_tobe->name : NULL)); + debug(("scmac alg is %s\r\n", scmac_tobe ? scmac_tobe->name : NULL)); + debug(("cscomp alg is %s\r\n", cscomp_tobe ? cscomp_tobe->name : NULL)); + debug(("sccomp alg is %s\r\n", sccomp_tobe ? sccomp_tobe->name : NULL)); + + /* + * Currently we only support Diffie-Hellman and DSS, so let's + * bomb out if those aren't selected. + */ + if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) + fatalbox("internal fault: chaos in SSH 2 transport layer"); + + /* + * Now we begin the fun. Generate and send e for Diffie-Hellman. + */ + e = dh_create_e(); + bndebug("e=", e); + ssh2_pkt_init(SSH2_MSG_KEXDH_INIT); + ssh2_pkt_addmp(e); + ssh2_pkt_send(); + + crWaitUntil(ispkt); + if (pktin.type != SSH2_MSG_KEXDH_REPLY) + fatalbox("expected key exchange packet from server"); + ssh2_pkt_getstring(&hostkeydata, &hostkeylen); + f = ssh2_pkt_getmp(); + bndebug("f=", f); + ssh2_pkt_getstring(&sigdata, &siglen); + + K = dh_find_K(f); + bndebug("K=", K); + + sha_string(&exhash, hostkeydata, hostkeylen); + sha_mpint(&exhash, e); + sha_mpint(&exhash, f); + sha_mpint(&exhash, K); + SHA_Final(&exhash, exchange_hash); + + debug(("Exchange hash is:\r\n")); + for (i = 0; i < 20; i++) + debug((" %02x", exchange_hash[i])); + debug(("\r\n")); + + /* + * FIXME: verify hostkeydata and sigdata. + */ + + crWaitUntil(0); + + crFinish(1); +} + +static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) { + crBegin; + + random_init(); + + while (!do_ssh2_kex(in, inlen, ispkt)) { + crReturnV; + } + + crFinishV; +} + +/* * Called to set up the connection. Will arrange for WM_NETEVENT * messages to be passed to the specified window, whose window * procedure should then call telnet_msg(). @@ -1025,7 +1637,7 @@ static void ssh_size(void) { break; case SSH_STATE_SESSION: if (!cfg.nopty) { - send_packet(SSH_CMSG_WINDOW_SIZE, + send_packet(SSH1_CMSG_WINDOW_SIZE, PKT_INT, rows, PKT_INT, cols, PKT_INT, 0, PKT_INT, 0, PKT_END); } @@ -1102,7 +1714,7 @@ int ssh_scp_recv(unsigned char *buf, int len) get_packet(); if (s == INVALID_SOCKET) return 0; - if (pktin.type == SSH_SMSG_STDOUT_DATA) { + if (pktin.type == SSH1_SMSG_STDOUT_DATA) { int plen = GET_32BIT(pktin.body); if (plen <= to_read) { memcpy(buf, pktin.body + 4, plen); @@ -1114,19 +1726,19 @@ int ssh_scp_recv(unsigned char *buf, int len) pending_input_ptr = pktin.body + 4 + to_read; to_read = 0; } - } else if (pktin.type == SSH_SMSG_STDERR_DATA) { + } else if (pktin.type == SSH1_SMSG_STDERR_DATA) { int plen = GET_32BIT(pktin.body); fwrite(pktin.body + 4, plen, 1, stderr); - } else if (pktin.type == SSH_MSG_DISCONNECT) { + } else if (pktin.type == SSH1_MSG_DISCONNECT) { logevent("Received disconnect request"); - } else if (pktin.type == SSH_SMSG_SUCCESS || - pktin.type == SSH_SMSG_FAILURE) { + } else if (pktin.type == SSH1_SMSG_SUCCESS || + pktin.type == SSH1_SMSG_FAILURE) { /* ignore */ - } else if (pktin.type == SSH_SMSG_EXIT_STATUS) { + } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) { char logbuf[100]; sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body)); logevent(logbuf); - send_packet(SSH_CMSG_EXIT_CONFIRMATION, PKT_END); + send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); logevent("Closing connection"); closesocket(s); s = INVALID_SOCKET; @@ -1148,7 +1760,7 @@ void ssh_scp_send(unsigned char *buf, int len) assert(IS_SCP); if (s == INVALID_SOCKET) return; - send_packet(SSH_CMSG_STDIN_DATA, + send_packet(SSH1_CMSG_STDIN_DATA, PKT_INT, len, PKT_DATA, buf, len, PKT_END); } @@ -1161,7 +1773,7 @@ void ssh_scp_send_eof(void) assert(IS_SCP); if (s == INVALID_SOCKET) return; - send_packet(SSH_CMSG_EOF, PKT_END); + send_packet(SSH1_CMSG_EOF, PKT_END); } /* @@ -1195,7 +1807,7 @@ char *ssh_scp_init(char *host, int port, char *cmd, char **realhost) get_packet(); if (s == INVALID_SOCKET) return "Connection closed by remote host"; - } while (!do_ssh_login(NULL, 0, 1)); + } while (!do_ssh1_login(NULL, 0, 1)); if (ssh_state == SSH_STATE_CLOSED) { closesocket(s); @@ -1206,7 +1818,7 @@ char *ssh_scp_init(char *host, int port, char *cmd, char **realhost) /* Execute command */ sprintf(buf, "Sending command: %.100s", cmd); logevent(buf); - send_packet(SSH_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); + send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); return NULL; } diff --git a/ssh.h b/ssh.h index a9057e72..e7be138c 100644 --- a/ssh.h +++ b/ssh.h @@ -1,10 +1,23 @@ #include +/* + * Useful thing. + */ +#ifndef lenof +#define lenof(x) ( (sizeof((x))) / (sizeof(*(x)))) +#endif + #define SSH_CIPHER_IDEA 1 #define SSH_CIPHER_DES 2 #define SSH_CIPHER_3DES 3 #define SSH_CIPHER_BLOWFISH 6 +#ifdef MSCRYPTOAPI +#define APIEXTRA 8 +#else +#define APIEXTRA 0 +#endif + struct RSAKey { int bits; int bytes; @@ -48,10 +61,43 @@ void MD5Update(struct MD5Context *context, unsigned char const *buf, unsigned len); void MD5Final(unsigned char digest[16], struct MD5Context *context); +typedef struct { + uint32 h[5]; + unsigned char block[64]; + int blkused; + uint32 lenhi, lenlo; +} SHA_State; + +void SHA_Init(SHA_State *s); +void SHA_Bytes(SHA_State *s, void *p, int len); +void SHA_Final(SHA_State *s, unsigned char *output); + struct ssh_cipher { void (*sesskey)(unsigned char *key); void (*encrypt)(unsigned char *blk, int len); void (*decrypt)(unsigned char *blk, int len); + char *name; + int blksize; +}; + +struct ssh_mac { + void (*sesskey)(unsigned char *key, int len); + void (*generate)(unsigned char *blk, int len, unsigned long seq); + int (*verify)(unsigned char *blk, int len, unsigned long seq); + char *name; + int len; +}; + +struct ssh_kex { + char *name; +}; + +struct ssh_hostkey { + char *name; +}; + +struct ssh_compress { + char *name; }; #ifndef MSCRYPTOAPI @@ -62,3 +108,17 @@ int random_byte(void); void random_add_noise(void *noise, int length); void logevent (char *); + +/* + * A Bignum is stored as a sequence of `unsigned short' words. The + * first tells how many remain; the remaining ones are digits, LS + * first. + */ +typedef unsigned short *Bignum; + +Bignum newbn(int length); +void freebn(Bignum b); +void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result); + +Bignum dh_create_e(void); +Bignum dh_find_K(Bignum f); diff --git a/sshblowf.c b/sshblowf.c index 7b97496b..364067a1 100644 --- a/sshblowf.c +++ b/sshblowf.c @@ -414,5 +414,7 @@ static void blowfish_decrypt_blk(unsigned char *blk, int len) struct ssh_cipher ssh_blowfish = { blowfish_sesskey, blowfish_encrypt_blk, - blowfish_decrypt_blk + blowfish_decrypt_blk, + "blowfish-cbc", + 8 }; diff --git a/sshbn.c b/sshbn.c new file mode 100644 index 00000000..a9eae859 --- /dev/null +++ b/sshbn.c @@ -0,0 +1,239 @@ +/* + * Bignum routines for RSA and DH and stuff. + */ + +#include +#include +#include + +#include "ssh.h" + +static unsigned short Zero[1] = { 0 }; + +#if defined TESTMODE || defined RSADEBUG +#ifndef DLVL +#define DLVL 10000 +#endif +#define debug(x) bndebug(#x,x) +static int level = 0; +static void bndebug(char *name, Bignum b) { + int i; + int w = 50-level-strlen(name)-5*b[0]; + if (level >= DLVL) + return; + if (w < 0) w = 0; + dprintf("%*s%s%*s", level, "", name, w, ""); + for (i=b[0]; i>0; i--) + dprintf(" %04x", b[i]); + dprintf("\n"); +} +#define dmsg(x) do {if(level= 0; j--) + c[j+len] = 0; + + for (i = len - 1; i >= 0; i--) { + ai = a[i]; + t = 0; + for (j = len - 1; j >= 0; j--) { + t += ai * (unsigned long) b[j]; + t += (unsigned long) c[i+j+1]; + c[i+j+1] = (unsigned short)t; + t = t >> 16; + } + c[i] = (unsigned short)t; + } +} + +/* + * Compute a = a % m. + * Input in first 2*len words of a and first len words of m. + * Output in first 2*len words of a (of which first len words will be zero). + * The MSW of m MUST have its high bit set. + */ +static void bigmod(unsigned short *a, unsigned short *m, int len) +{ + unsigned short m0, m1; + unsigned int h; + int i, k; + + /* Special case for len == 1 */ + if (len == 1) { + a[1] = (((long) a[0] << 16) + a[1]) % m[0]; + a[0] = 0; + return; + } + + m0 = m[0]; + m1 = m[1]; + + for (i = 0; i <= len; i++) { + unsigned long t; + unsigned int q, r, c; + + if (i == 0) { + h = 0; + } else { + h = a[i-1]; + a[i-1] = 0; + } + + /* Find q = h:a[i] / m0 */ + t = ((unsigned long) h << 16) + a[i]; + q = t / m0; + r = t % m0; + + /* Refine our estimate of q by looking at + h:a[i]:a[i+1] / m0:m1 */ + t = (long) m1 * (long) q; + if (t > ((unsigned long) r << 16) + a[i+1]) { + q--; + t -= m1; + r = (r + m0) & 0xffff; /* overflow? */ + if (r >= (unsigned long)m0 && + t > ((unsigned long) r << 16) + a[i+1]) + q--; + } + + /* Substract q * m from a[i...] */ + c = 0; + for (k = len - 1; k >= 0; k--) { + t = (long) q * (long) m[k]; + t += c; + c = t >> 16; + if ((unsigned short) t > a[i+k]) c++; + a[i+k] -= (unsigned short) t; + } + + /* Add back m in case of borrow */ + if (c != h) { + t = 0; + for (k = len - 1; k >= 0; k--) { + t += m[k]; + t += a[i+k]; + a[i+k] = (unsigned short)t; + t = t >> 16; + } + } + } +} + +/* + * Compute (base ^ exp) % mod. + * The base MUST be smaller than the modulus. + * The most significant word of mod MUST be non-zero. + * We assume that the result array is the same size as the mod array. + */ +void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result) +{ + unsigned short *a, *b, *n, *m; + int mshift; + int mlen, i, j; + + /* Allocate m of size mlen, copy mod to m */ + /* We use big endian internally */ + mlen = mod[0]; + m = malloc(mlen * sizeof(unsigned short)); + for (j = 0; j < mlen; j++) m[j] = mod[mod[0] - j]; + + /* Shift m left to make msb bit set */ + for (mshift = 0; mshift < 15; mshift++) + if ((m[0] << mshift) & 0x8000) break; + if (mshift) { + for (i = 0; i < mlen - 1; i++) + m[i] = (m[i] << mshift) | (m[i+1] >> (16-mshift)); + m[mlen-1] = m[mlen-1] << mshift; + } + + /* Allocate n of size mlen, copy base to n */ + n = malloc(mlen * sizeof(unsigned short)); + i = mlen - base[0]; + for (j = 0; j < i; j++) n[j] = 0; + for (j = 0; j < base[0]; j++) n[i+j] = base[base[0] - j]; + + /* Allocate a and b of size 2*mlen. Set a = 1 */ + a = malloc(2 * mlen * sizeof(unsigned short)); + b = malloc(2 * mlen * sizeof(unsigned short)); + for (i = 0; i < 2*mlen; i++) a[i] = 0; + a[2*mlen-1] = 1; + + /* Skip leading zero bits of exp. */ + i = 0; j = 15; + while (i < exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) { + j--; + if (j < 0) { i++; j = 15; } + } + + /* Main computation */ + while (i < exp[0]) { + while (j >= 0) { + bigmul(a + mlen, a + mlen, b, mlen); + bigmod(b, m, mlen); + if ((exp[exp[0] - i] & (1 << j)) != 0) { + bigmul(b + mlen, n, a, mlen); + bigmod(a, m, mlen); + } else { + unsigned short *t; + t = a; a = b; b = t; + } + j--; + } + i++; j = 15; + } + + /* Fixup result in case the modulus was shifted */ + if (mshift) { + for (i = mlen - 1; i < 2*mlen - 1; i++) + a[i] = (a[i] << mshift) | (a[i+1] >> (16-mshift)); + a[2*mlen-1] = a[2*mlen-1] << mshift; + bigmod(a, m, mlen); + for (i = 2*mlen - 1; i >= mlen; i--) + a[i] = (a[i] >> mshift) | (a[i-1] << (16-mshift)); + } + + /* Copy result to buffer */ + for (i = 0; i < mlen; i++) + result[result[0] - i] = a[i+mlen]; + + /* Free temporary arrays */ + for (i = 0; i < 2*mlen; i++) a[i] = 0; free(a); + for (i = 0; i < 2*mlen; i++) b[i] = 0; free(b); + for (i = 0; i < mlen; i++) m[i] = 0; free(m); + for (i = 0; i < mlen; i++) n[i] = 0; free(n); +} diff --git a/sshdes.c b/sshdes.c index 1b684796..0e90e644 100644 --- a/sshdes.c +++ b/sshdes.c @@ -685,7 +685,9 @@ static void des3_decrypt_blk(unsigned char *blk, int len) { struct ssh_cipher ssh_3des = { des3_sesskey, des3_encrypt_blk, - des3_decrypt_blk + des3_decrypt_blk, + "3des-cbc", + 8 }; static void des_sesskey(unsigned char *key) { @@ -705,5 +707,7 @@ static void des_decrypt_blk(unsigned char *blk, int len) { struct ssh_cipher ssh_des = { des_sesskey, des_encrypt_blk, - des_decrypt_blk + des_decrypt_blk, + "des-cbc", /* should never be used - not a valid cipher in ssh2 */ + 8 }; diff --git a/sshdh.c b/sshdh.c new file mode 100644 index 00000000..d556a252 --- /dev/null +++ b/sshdh.c @@ -0,0 +1,115 @@ +#include "ssh.h" + +struct ssh_kex ssh_diffiehellman = { + "diffie-hellman-group1-sha1" +}; + +/* + * The prime p used in the key exchange. + */ +static unsigned short P[] = { + 64, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0x5381, 0xECE6, 0x6651, 0x4928, + 0x1FE6, 0x7C4B, 0x2411, 0xAE9F, 0x9FA5, 0x5A89, 0x6BFB, 0xEE38, + 0xB7ED, 0xF406, 0x5CB6, 0x0BFF, 0xED6B, 0xA637, 0x42E9, 0xF44C, + 0x7EC6, 0x625E, 0xB576, 0xE485, 0xC245, 0x6D51, 0x356D, 0x4FE1, + 0x1437, 0xF25F, 0x0A6D, 0x302B, 0x431B, 0xCD3A, 0x19B3, 0xEF95, + 0x04DD, 0x8E34, 0x0879, 0x514A, 0x9B22, 0x3B13, 0xBEA6, 0x020B, + 0xCC74, 0x8A67, 0x4E08, 0x2902, 0x1CD1, 0x80DC, 0x628B, 0xC4C6, + 0xC234, 0x2168, 0xDAA2, 0xC90F, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, +}; + +/* + * The order q of the group: (p-1)/2. + */ +static unsigned short Q[] = { + 64, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0x29C0, 0xF673, 0x3328, 0x2494, + 0x8FF3, 0xBE25, 0x9208, 0xD74F, 0xCFD2, 0xAD44, 0x35FD, 0xF71C, + 0x5BF6, 0x7A03, 0xAE5B, 0x85FF, 0xF6B5, 0xD31B, 0x2174, 0x7A26, + 0x3F63, 0x312F, 0xDABB, 0xF242, 0xE122, 0xB6A8, 0x9AB6, 0xA7F0, + 0x8A1B, 0xF92F, 0x8536, 0x9815, 0x218D, 0xE69D, 0x8CD9, 0xF7CA, + 0x026E, 0xC71A, 0x043C, 0x28A5, 0xCD91, 0x1D89, 0xDF53, 0x0105, + 0xE63A, 0x4533, 0x2704, 0x9481, 0x0E68, 0xC06E, 0x3145, 0x6263, + 0x611A, 0x10B4, 0xED51, 0xE487, 0xFFFF, 0xFFFF, 0xFFFF, 0x7FFF, +}; + +/* + * The bitmask covering q (for ease of generation of x). + */ +static unsigned short Qmask[] = { + 64, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0x7FFF, +}; + +/* + * The generator g = 2. + */ +static unsigned short G[] = { 1, 2 }; + +/* + * Variables. + */ +static Bignum x, e; + +/* + * DH stage 1: invent a number x between 1 and q, and compute e = + * g^x mod p. Return e. + */ +Bignum dh_create_e(void) { + int i; + + x = newbn(Q[0]); + + tryagain: + + /* + * Create a potential x, by ANDing a string of random bytes + * with Qmask. + */ + for (i = 1; i <= x[0]; i++) + x[i] = ((random_byte() << 8) + random_byte()) & Qmask[i]; + + /* + * If x <= 1, go round again. + */ + for (i = 2; i <= x[0]; i++) + if (x[i] != 0) + break; + if (i > x[0] && x[1] <= 1) + goto tryagain; + + /* + * If x >= q, go round again. + */ + for (i = x[0]; i > 0; i--) { + if (x[i] > Q[i]) + goto tryagain; + if (x[i] < Q[i]) + break; + } + + /* + * Done. Now compute e = g^x mod p. + */ + e = newbn(P[0]); + modpow(G, x, P, e); + + return e; +} + +/* + * DH stage 2: given a number f, compute K = f^x mod p. + */ +Bignum dh_find_K(Bignum f) { + Bignum K = newbn(P[0]); + modpow(f, x, P, K); + return K; +} diff --git a/sshdss.c b/sshdss.c new file mode 100644 index 00000000..c651140e --- /dev/null +++ b/sshdss.c @@ -0,0 +1,5 @@ +#include "ssh.h" + +struct ssh_hostkey ssh_dss = { + "ssh-dss" +}; diff --git a/sshrsa.c b/sshrsa.c index d13f6cfe..bf54e409 100644 --- a/sshrsa.c +++ b/sshrsa.c @@ -9,12 +9,6 @@ #include #include -#include "ssh.h" - -typedef unsigned short *Bignum; - -static unsigned short Zero[1] = { 0 }; - #if defined TESTMODE || defined RSADEBUG #ifndef DLVL #define DLVL 10000 @@ -42,201 +36,7 @@ static void bndebug(char *name, Bignum b) { #define leave(x) #endif -static Bignum newbn(int length) { - Bignum b = malloc((length+1)*sizeof(unsigned short)); - if (!b) - abort(); /* FIXME */ - b[0] = length; - return b; -} - -static void freebn(Bignum b) { - free(b); -} - -/* - * Compute c = a * b. - * Input is in the first len words of a and b. - * Result is returned in the first 2*len words of c. - */ -static void bigmul(unsigned short *a, unsigned short *b, unsigned short *c, - int len) -{ - int i, j; - unsigned long ai, t; - - for (j = len - 1; j >= 0; j--) - c[j+len] = 0; - - for (i = len - 1; i >= 0; i--) { - ai = a[i]; - t = 0; - for (j = len - 1; j >= 0; j--) { - t += ai * (unsigned long) b[j]; - t += (unsigned long) c[i+j+1]; - c[i+j+1] = (unsigned short)t; - t = t >> 16; - } - c[i] = (unsigned short)t; - } -} - -/* - * Compute a = a % m. - * Input in first 2*len words of a and first len words of m. - * Output in first 2*len words of a (of which first len words will be zero). - * The MSW of m MUST have its high bit set. - */ -static void bigmod(unsigned short *a, unsigned short *m, int len) -{ - unsigned short m0, m1; - unsigned int h; - int i, k; - - /* Special case for len == 1 */ - if (len == 1) { - a[1] = (((long) a[0] << 16) + a[1]) % m[0]; - a[0] = 0; - return; - } - - m0 = m[0]; - m1 = m[1]; - - for (i = 0; i <= len; i++) { - unsigned long t; - unsigned int q, r, c; - - if (i == 0) { - h = 0; - } else { - h = a[i-1]; - a[i-1] = 0; - } - - /* Find q = h:a[i] / m0 */ - t = ((unsigned long) h << 16) + a[i]; - q = t / m0; - r = t % m0; - - /* Refine our estimate of q by looking at - h:a[i]:a[i+1] / m0:m1 */ - t = (long) m1 * (long) q; - if (t > ((unsigned long) r << 16) + a[i+1]) { - q--; - t -= m1; - r = (r + m0) & 0xffff; /* overflow? */ - if (r >= (unsigned long)m0 && - t > ((unsigned long) r << 16) + a[i+1]) - q--; - } - - /* Substract q * m from a[i...] */ - c = 0; - for (k = len - 1; k >= 0; k--) { - t = (long) q * (long) m[k]; - t += c; - c = t >> 16; - if ((unsigned short) t > a[i+k]) c++; - a[i+k] -= (unsigned short) t; - } - - /* Add back m in case of borrow */ - if (c != h) { - t = 0; - for (k = len - 1; k >= 0; k--) { - t += m[k]; - t += a[i+k]; - a[i+k] = (unsigned short)t; - t = t >> 16; - } - } - } -} - -/* - * Compute (base ^ exp) % mod. - * The base MUST be smaller than the modulus. - * The most significant word of mod MUST be non-zero. - * We assume that the result array is the same size as the mod array. - */ -static void modpow(Bignum base, Bignum exp, Bignum mod, Bignum result) -{ - unsigned short *a, *b, *n, *m; - int mshift; - int mlen, i, j; - - /* Allocate m of size mlen, copy mod to m */ - /* We use big endian internally */ - mlen = mod[0]; - m = malloc(mlen * sizeof(unsigned short)); - for (j = 0; j < mlen; j++) m[j] = mod[mod[0] - j]; - - /* Shift m left to make msb bit set */ - for (mshift = 0; mshift < 15; mshift++) - if ((m[0] << mshift) & 0x8000) break; - if (mshift) { - for (i = 0; i < mlen - 1; i++) - m[i] = (m[i] << mshift) | (m[i+1] >> (16-mshift)); - m[mlen-1] = m[mlen-1] << mshift; - } - - /* Allocate n of size mlen, copy base to n */ - n = malloc(mlen * sizeof(unsigned short)); - i = mlen - base[0]; - for (j = 0; j < i; j++) n[j] = 0; - for (j = 0; j < base[0]; j++) n[i+j] = base[base[0] - j]; - - /* Allocate a and b of size 2*mlen. Set a = 1 */ - a = malloc(2 * mlen * sizeof(unsigned short)); - b = malloc(2 * mlen * sizeof(unsigned short)); - for (i = 0; i < 2*mlen; i++) a[i] = 0; - a[2*mlen-1] = 1; - - /* Skip leading zero bits of exp. */ - i = 0; j = 15; - while (i < exp[0] && (exp[exp[0] - i] & (1 << j)) == 0) { - j--; - if (j < 0) { i++; j = 15; } - } - - /* Main computation */ - while (i < exp[0]) { - while (j >= 0) { - bigmul(a + mlen, a + mlen, b, mlen); - bigmod(b, m, mlen); - if ((exp[exp[0] - i] & (1 << j)) != 0) { - bigmul(b + mlen, n, a, mlen); - bigmod(a, m, mlen); - } else { - unsigned short *t; - t = a; a = b; b = t; - } - j--; - } - i++; j = 15; - } - - /* Fixup result in case the modulus was shifted */ - if (mshift) { - for (i = mlen - 1; i < 2*mlen - 1; i++) - a[i] = (a[i] << mshift) | (a[i+1] >> (16-mshift)); - a[2*mlen-1] = a[2*mlen-1] << mshift; - bigmod(a, m, mlen); - for (i = 2*mlen - 1; i >= mlen; i--) - a[i] = (a[i] >> mshift) | (a[i-1] << (16-mshift)); - } - - /* Copy result to buffer */ - for (i = 0; i < mlen; i++) - result[result[0] - i] = a[i+mlen]; - - /* Free temporary arrays */ - for (i = 0; i < 2*mlen; i++) a[i] = 0; free(a); - for (i = 0; i < 2*mlen; i++) b[i] = 0; free(b); - for (i = 0; i < mlen; i++) m[i] = 0; free(m); - for (i = 0; i < mlen; i++) n[i] = 0; free(n); -} +#include "ssh.h" int makekey(unsigned char *data, struct RSAKey *result, unsigned char **keystr) { diff --git a/sshsha.c b/sshsha.c index d766743f..487d1733 100644 --- a/sshsha.c +++ b/sshsha.c @@ -1,12 +1,27 @@ /* - * SHA core transform algorithm, used here solely as a `stirring' - * function for the PuTTY random number pool. Implemented directly - * from the specification by Simon Tatham. + * SHA1 hash algorithm. Used in SSH2 as a MAC, and the transform is + * also used as a `stirring' function for the PuTTY random number + * pool. Implemented directly from the specification by Simon + * Tatham. */ #include "ssh.h" -#define rol(x,y) ( ((x) << (y)) | (((word32)x) >> (32-y)) ) +typedef unsigned int uint32; + +/* ---------------------------------------------------------------------- + * Core SHA algorithm: processes 16-word blocks into a message digest. + */ + +#define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) + +void SHA_Core_Init(uint32 h[5]) { + h[0] = 0x67452301; + h[1] = 0xefcdab89; + h[2] = 0x98badcfe; + h[3] = 0x10325476; + h[4] = 0xc3d2e1f0; +} void SHATransform(word32 *digest, word32 *block) { word32 w[80]; @@ -50,3 +65,165 @@ void SHATransform(word32 *digest, word32 *block) { digest[3] += d; digest[4] += e; } + +/* ---------------------------------------------------------------------- + * Outer SHA algorithm: take an arbitrary length byte string, + * convert it into 16-word blocks with the prescribed padding at + * the end, and pass those blocks to the core SHA algorithm. + */ + +void SHA_Init(SHA_State *s) { + SHA_Core_Init(s->h); + s->blkused = 0; + s->lenhi = s->lenlo = 0; +} + +void SHA_Bytes(SHA_State *s, void *p, int len) { + unsigned char *q = (unsigned char *)p; + uint32 wordblock[16]; + uint32 lenw = len; + int i; + + /* + * Update the length field. + */ + s->lenlo += lenw; + s->lenhi += (s->lenlo < lenw); + + if (s->blkused && s->blkused+len < 64) { + /* + * Trivial case: just add to the block. + */ + memcpy(s->block + s->blkused, q, len); + s->blkused += len; + } else { + /* + * We must complete and process at least one block. + */ + while (s->blkused + len >= 64) { + memcpy(s->block + s->blkused, q, 64 - s->blkused); + q += 64 - s->blkused; + len -= 64 - s->blkused; + /* Now process the block. Gather bytes big-endian into words */ + for (i = 0; i < 16; i++) { + wordblock[i] = + ( ((uint32)s->block[i*4+0]) << 24 ) | + ( ((uint32)s->block[i*4+1]) << 16 ) | + ( ((uint32)s->block[i*4+2]) << 8 ) | + ( ((uint32)s->block[i*4+3]) << 0 ); + } + SHATransform(s->h, wordblock); + s->blkused = 0; + } + memcpy(s->block, q, len); + s->blkused = len; + } +} + +void SHA_Final(SHA_State *s, unsigned char *output) { + int i; + int pad; + unsigned char c[64]; + uint32 lenhi, lenlo; + + if (s->blkused >= 56) + pad = 56 + 64 - s->blkused; + else + pad = 56 - s->blkused; + + lenhi = (s->lenhi << 3) | (s->lenlo >> (32-3)); + lenlo = (s->lenlo << 3); + + memset(c, 0, pad); + c[0] = 0x80; + SHA_Bytes(s, &c, pad); + + c[0] = (lenhi >> 24) & 0xFF; + c[1] = (lenhi >> 16) & 0xFF; + c[2] = (lenhi >> 8) & 0xFF; + c[3] = (lenhi >> 0) & 0xFF; + c[4] = (lenlo >> 24) & 0xFF; + c[5] = (lenlo >> 16) & 0xFF; + c[6] = (lenlo >> 8) & 0xFF; + c[7] = (lenlo >> 0) & 0xFF; + + SHA_Bytes(s, &c, 8); + + for (i = 0; i < 5; i++) { + output[i*4 ] = (s->h[i] >> 24) & 0xFF; + output[i*4+1] = (s->h[i] >> 16) & 0xFF; + output[i*4+2] = (s->h[i] >> 8) & 0xFF; + output[i*4+3] = (s->h[i] ) & 0xFF; + } +} + +void SHA_Simple(void *p, int len, unsigned char *output) { + SHA_State s; + + SHA_Init(&s); + SHA_Bytes(&s, p, len); + SHA_Final(&s, output); +} + +/* ---------------------------------------------------------------------- + * The above is the SHA-1 algorithm itself. Now we implement the + * HMAC wrapper on it. + */ + +static SHA_State sha1_mac_s1, sha1_mac_s2; + +static void sha1_sesskey(unsigned char *key, int len) { + unsigned char foo[64]; + int i; + + memset(foo, 0x36, 64); + for (i = 0; i < len && i < 64; i++) + foo[i] ^= key[i]; + SHA_Init(&sha1_mac_s1); + SHA_Bytes(&sha1_mac_s1, foo, 64); + + memset(foo, 0x5C, 64); + for (i = 0; i < len && i < 64; i++) + foo[i] ^= key[i]; + SHA_Init(&sha1_mac_s2); + SHA_Bytes(&sha1_mac_s2, foo, 64); + + memset(foo, 0, 64); /* burn the evidence */ +} + +static void sha1_do_hmac(unsigned char *blk, int len, unsigned long seq, + unsigned char *hmac) { + SHA_State s; + unsigned char intermediate[20]; + + intermediate[0] = (unsigned char)((seq >> 24) & 0xFF); + intermediate[1] = (unsigned char)((seq >> 16) & 0xFF); + intermediate[2] = (unsigned char)((seq >> 8) & 0xFF); + intermediate[3] = (unsigned char)((seq ) & 0xFF); + + s = sha1_mac_s1; /* structure copy */ + SHA_Bytes(&s, intermediate, 4); + SHA_Bytes(&s, blk, len); + SHA_Final(&s, intermediate); + s = sha1_mac_s2; /* structure copy */ + SHA_Bytes(&s, intermediate, 20); + SHA_Final(&s, hmac); +} + +static void sha1_generate(unsigned char *blk, int len, unsigned long seq) { + sha1_do_hmac(blk, len, seq, blk+len); +} + +static int sha1_verify(unsigned char *blk, int len, unsigned long seq) { + unsigned char correct[20]; + sha1_do_hmac(blk, len, seq, correct); + return !memcmp(correct, blk+len, 20); +} + +struct ssh_mac ssh_sha1 = { + sha1_sesskey, + sha1_generate, + sha1_verify, + "hmac-sha1", + 20 +}; -- 2.11.0