mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-10 01:48:00 +00:00
Improve SSH2 host key abstraction into a generic `signing key'
abstraction, so as to be able to re-use the same abstraction for user authentication keys and probably in the SSH2 agent (when that happens) as well. [originally from svn r815]
This commit is contained in:
Simon Tatham
parent
6bdd92be5f
commit
8eca227b92
16
ssh.c
16
ssh.c
@ -171,8 +171,8 @@ const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2
|
||||
extern const struct ssh_kex ssh_diffiehellman;
|
||||
const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
|
||||
|
||||
extern const struct ssh_hostkey ssh_dss;
|
||||
const static struct ssh_hostkey *hostkey_algs[] = { &ssh_dss };
|
||||
extern const struct ssh_signkey ssh_dss;
|
||||
const static struct ssh_signkey *hostkey_algs[] = { &ssh_dss };
|
||||
|
||||
extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy;
|
||||
|
||||
@ -246,7 +246,7 @@ static const struct ssh_mac *scmac = NULL;
|
||||
static const struct ssh_compress *cscomp = NULL;
|
||||
static const struct ssh_compress *sccomp = NULL;
|
||||
static const struct ssh_kex *kex = NULL;
|
||||
static const struct ssh_hostkey *hostkey = NULL;
|
||||
static const struct ssh_signkey *hostkey = NULL;
|
||||
int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
|
||||
|
||||
static char *savedhost;
|
||||
@ -1987,6 +1987,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
|
||||
static const struct ssh_compress *sccomp_tobe = NULL;
|
||||
static char *hostkeydata, *sigdata, *keystr, *fingerprint;
|
||||
static int hostkeylen, siglen;
|
||||
static void *hkey; /* actual host key */
|
||||
static unsigned char exchange_hash[20];
|
||||
static unsigned char keyspace[40];
|
||||
static const struct ssh_cipher *preferred_cipher;
|
||||
@ -2216,8 +2217,8 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
|
||||
debug(("\r\n"));
|
||||
#endif
|
||||
|
||||
hostkey->setkey(hostkeydata, hostkeylen);
|
||||
if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20)) {
|
||||
hkey = hostkey->newkey(hostkeydata, hostkeylen);
|
||||
if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
|
||||
bombout(("Server failed host key check"));
|
||||
crReturn(0);
|
||||
}
|
||||
@ -2235,14 +2236,15 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
|
||||
* Authenticate remote host: verify host key. (We've already
|
||||
* checked the signature of the exchange hash.)
|
||||
*/
|
||||
keystr = hostkey->fmtkey();
|
||||
fingerprint = hostkey->fingerprint();
|
||||
keystr = hostkey->fmtkey(hkey);
|
||||
fingerprint = hostkey->fingerprint(hkey);
|
||||
verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
|
||||
keystr, fingerprint);
|
||||
logevent("Host key fingerprint is:");
|
||||
logevent(fingerprint);
|
||||
free(fingerprint);
|
||||
free(keystr);
|
||||
hostkey->freekey(hkey);
|
||||
|
||||
/*
|
||||
* Send SSH2_MSG_NEWKEYS.
|
||||
|
||||
14
ssh.h
14
ssh.h
@ -126,11 +126,15 @@ struct ssh_kex {
|
||||
char *name;
|
||||
};
|
||||
|
||||
struct ssh_hostkey {
|
||||
void (*setkey)(char *data, int len);
|
||||
char *(*fmtkey)(void);
|
||||
char *(*fingerprint)(void);
|
||||
int (*verifysig)(char *sig, int siglen, char *data, int datalen);
|
||||
struct ssh_signkey {
|
||||
void *(*newkey)(char *data, int len);
|
||||
void (*freekey)(void *key);
|
||||
char *(*fmtkey)(void *key);
|
||||
char *(*fingerprint)(void *key);
|
||||
int (*verifysig)(void *key, char *sig, int siglen,
|
||||
char *data, int datalen);
|
||||
int (*sign)(void *key, char *sig, int siglen,
|
||||
char *data, int datalen);
|
||||
char *name;
|
||||
char *keytype; /* for host key cache */
|
||||
};
|
||||
|
||||
108
sshdss.c
108
sshdss.c
@ -93,11 +93,17 @@ static Bignum get160(char **data, int *datalen) {
|
||||
return b;
|
||||
}
|
||||
|
||||
static Bignum dss_p, dss_q, dss_g, dss_y;
|
||||
struct dss_key {
|
||||
Bignum p, q, g, y;
|
||||
};
|
||||
|
||||
static void dss_setkey(char *data, int len) {
|
||||
static void *dss_newkey(char *data, int len) {
|
||||
char *p;
|
||||
int slen;
|
||||
struct dss_key *dss;
|
||||
|
||||
dss = malloc(sizeof(struct dss_key));
|
||||
if (!dss) return NULL;
|
||||
getstring(&data, &len, &p, &slen);
|
||||
|
||||
#ifdef DEBUG_DSS
|
||||
@ -111,48 +117,61 @@ static void dss_setkey(char *data, int len) {
|
||||
#endif
|
||||
|
||||
if (!p || memcmp(p, "ssh-dss", 7)) {
|
||||
dss_p = NULL;
|
||||
return;
|
||||
free(dss);
|
||||
return NULL;
|
||||
}
|
||||
dss_p = getmp(&data, &len);
|
||||
dss_q = getmp(&data, &len);
|
||||
dss_g = getmp(&data, &len);
|
||||
dss_y = getmp(&data, &len);
|
||||
dss->p = getmp(&data, &len);
|
||||
dss->q = getmp(&data, &len);
|
||||
dss->g = getmp(&data, &len);
|
||||
dss->y = getmp(&data, &len);
|
||||
|
||||
return dss;
|
||||
}
|
||||
|
||||
static char *dss_fmtkey(void) {
|
||||
static void dss_freekey(void *key) {
|
||||
struct dss_key *dss = (struct dss_key *)key;
|
||||
freebn(dss->p);
|
||||
freebn(dss->q);
|
||||
freebn(dss->g);
|
||||
freebn(dss->y);
|
||||
free(dss);
|
||||
}
|
||||
|
||||
static char *dss_fmtkey(void *key) {
|
||||
struct dss_key *dss = (struct dss_key *)key;
|
||||
char *p;
|
||||
int len, i, pos, nibbles;
|
||||
static const char hex[] = "0123456789abcdef";
|
||||
if (!dss_p)
|
||||
if (!dss->p)
|
||||
return NULL;
|
||||
len = 8 + 4 + 1; /* 4 x "0x", punctuation, \0 */
|
||||
len += 4 * (dss_p[0] + dss_q[0] + dss_g[0] + dss_y[0]); /* digits */
|
||||
len += 4 * (dss->p[0] + dss->q[0] + dss->g[0] + dss->y[0]); /* digits */
|
||||
p = malloc(len);
|
||||
if (!p) return NULL;
|
||||
|
||||
pos = 0;
|
||||
pos += sprintf(p+pos, "0x");
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss_p))/4; if (nibbles<1) nibbles=1;
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss->p))/4; if (nibbles<1) nibbles=1;
|
||||
for (i=nibbles; i-- ;)
|
||||
p[pos++] = hex[(bignum_byte(dss_p, i/2) >> (4*(i%2))) & 0xF];
|
||||
p[pos++] = hex[(bignum_byte(dss->p, i/2) >> (4*(i%2))) & 0xF];
|
||||
pos += sprintf(p+pos, ",0x");
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss_q))/4; if (nibbles<1) nibbles=1;
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss->q))/4; if (nibbles<1) nibbles=1;
|
||||
for (i=nibbles; i-- ;)
|
||||
p[pos++] = hex[(bignum_byte(dss_q, i/2) >> (4*(i%2))) & 0xF];
|
||||
p[pos++] = hex[(bignum_byte(dss->q, i/2) >> (4*(i%2))) & 0xF];
|
||||
pos += sprintf(p+pos, ",0x");
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss_g))/4; if (nibbles<1) nibbles=1;
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss->g))/4; if (nibbles<1) nibbles=1;
|
||||
for (i=nibbles; i-- ;)
|
||||
p[pos++] = hex[(bignum_byte(dss_g, i/2) >> (4*(i%2))) & 0xF];
|
||||
p[pos++] = hex[(bignum_byte(dss->g, i/2) >> (4*(i%2))) & 0xF];
|
||||
pos += sprintf(p+pos, ",0x");
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss_y))/4; if (nibbles<1) nibbles=1;
|
||||
nibbles = (3 + ssh1_bignum_bitcount(dss->y))/4; if (nibbles<1) nibbles=1;
|
||||
for (i=nibbles; i-- ;)
|
||||
p[pos++] = hex[(bignum_byte(dss_y, i/2) >> (4*(i%2))) & 0xF];
|
||||
p[pos++] = hex[(bignum_byte(dss->y, i/2) >> (4*(i%2))) & 0xF];
|
||||
p[pos] = '\0';
|
||||
return p;
|
||||
}
|
||||
|
||||
static char *dss_fingerprint(void) {
|
||||
static char *dss_fingerprint(void *key) {
|
||||
struct dss_key *dss = (struct dss_key *)key;
|
||||
struct MD5Context md5c;
|
||||
unsigned char digest[16], lenbuf[4];
|
||||
char buffer[16*3+40];
|
||||
@ -169,15 +188,15 @@ static char *dss_fingerprint(void) {
|
||||
unsigned char c = bignum_byte(bignum, i); \
|
||||
MD5Update(&md5c, &c, 1); \
|
||||
}
|
||||
ADD_BIGNUM(dss_p);
|
||||
ADD_BIGNUM(dss_q);
|
||||
ADD_BIGNUM(dss_g);
|
||||
ADD_BIGNUM(dss_y);
|
||||
ADD_BIGNUM(dss->p);
|
||||
ADD_BIGNUM(dss->q);
|
||||
ADD_BIGNUM(dss->g);
|
||||
ADD_BIGNUM(dss->y);
|
||||
#undef ADD_BIGNUM
|
||||
|
||||
MD5Final(digest, &md5c);
|
||||
|
||||
sprintf(buffer, "%d ", ssh1_bignum_bitcount(dss_p));
|
||||
sprintf(buffer, "%d ", ssh1_bignum_bitcount(dss->p));
|
||||
for (i = 0; i < 16; i++)
|
||||
sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
|
||||
ret = malloc(strlen(buffer)+1);
|
||||
@ -186,14 +205,16 @@ static char *dss_fingerprint(void) {
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
|
||||
static int dss_verifysig(void *key, char *sig, int siglen,
|
||||
char *data, int datalen) {
|
||||
struct dss_key *dss = (struct dss_key *)key;
|
||||
char *p;
|
||||
int slen;
|
||||
char hash[20];
|
||||
Bignum r, s, w, gu1p, yu2p, gu1yu2p, u1, u2, sha, v;
|
||||
int ret;
|
||||
|
||||
if (!dss_p)
|
||||
if (!dss->p)
|
||||
return 0;
|
||||
|
||||
#ifdef DEBUG_DSS
|
||||
@ -223,10 +244,10 @@ static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
|
||||
}
|
||||
sig += 4, siglen -= 4; /* skip yet another length field */
|
||||
}
|
||||
diagbn("p=", dss_p);
|
||||
diagbn("q=", dss_q);
|
||||
diagbn("g=", dss_g);
|
||||
diagbn("y=", dss_y);
|
||||
diagbn("p=", dss->p);
|
||||
diagbn("q=", dss->q);
|
||||
diagbn("g=", dss->g);
|
||||
diagbn("y=", dss->y);
|
||||
r = get160(&sig, &siglen);
|
||||
diagbn("r=", r);
|
||||
s = get160(&sig, &siglen);
|
||||
@ -237,7 +258,7 @@ static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
|
||||
/*
|
||||
* Step 1. w <- s^-1 mod q.
|
||||
*/
|
||||
w = modinv(s, dss_q);
|
||||
w = modinv(s, dss->q);
|
||||
diagbn("w=", w);
|
||||
|
||||
/*
|
||||
@ -246,25 +267,25 @@ static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
|
||||
SHA_Simple(data, datalen, hash);
|
||||
p = hash; slen = 20; sha = get160(&p, &slen);
|
||||
diagbn("sha=", sha);
|
||||
u1 = modmul(sha, w, dss_q);
|
||||
u1 = modmul(sha, w, dss->q);
|
||||
diagbn("u1=", u1);
|
||||
|
||||
/*
|
||||
* Step 3. u2 <- r * w mod q.
|
||||
*/
|
||||
u2 = modmul(r, w, dss_q);
|
||||
u2 = modmul(r, w, dss->q);
|
||||
diagbn("u2=", u2);
|
||||
|
||||
/*
|
||||
* Step 4. v <- (g^u1 * y^u2 mod p) mod q.
|
||||
*/
|
||||
gu1p = modpow(dss_g, u1, dss_p);
|
||||
gu1p = modpow(dss->g, u1, dss->p);
|
||||
diagbn("gu1p=", gu1p);
|
||||
yu2p = modpow(dss_y, u2, dss_p);
|
||||
yu2p = modpow(dss->y, u2, dss->p);
|
||||
diagbn("yu2p=", yu2p);
|
||||
gu1yu2p = modmul(gu1p, yu2p, dss_p);
|
||||
gu1yu2p = modmul(gu1p, yu2p, dss->p);
|
||||
diagbn("gu1yu2p=", gu1yu2p);
|
||||
v = modmul(gu1yu2p, One, dss_q);
|
||||
v = modmul(gu1yu2p, One, dss->q);
|
||||
diagbn("gu1yu2q=v=", v);
|
||||
diagbn("r=", r);
|
||||
|
||||
@ -286,11 +307,18 @@ static int dss_verifysig(char *sig, int siglen, char *data, int datalen) {
|
||||
return ret;
|
||||
}
|
||||
|
||||
struct ssh_hostkey ssh_dss = {
|
||||
dss_setkey,
|
||||
int dss_sign(void *key, char *sig, int siglen,
|
||||
char *data, int datalen) {
|
||||
return 0; /* do nothing */
|
||||
}
|
||||
|
||||
struct ssh_signkey ssh_dss = {
|
||||
dss_newkey,
|
||||
dss_freekey,
|
||||
dss_fmtkey,
|
||||
dss_fingerprint,
|
||||
dss_verifysig,
|
||||
dss_sign,
|
||||
"ssh-dss",
|
||||
"dss"
|
||||
};
|
||||
|
||||
Loading…
Reference in New Issue
Block a user