/*
- * RSA implementation just sufficient for ssh client-side
- * initialisation step
- *
- * Rewritten for more speed by Joris van Rantwijk, Jun 1999.
+ * RSA implementation for PuTTY.
*/
#include <stdio.h>
#include <assert.h>
#include "ssh.h"
+#include "misc.h"
-
-int makekey(unsigned char *data, struct RSAKey *result,
- unsigned char **keystr, int order) {
+int makekey(unsigned char *data, int len, struct RSAKey *result,
+ unsigned char **keystr, int order)
+{
unsigned char *p = data;
- int i;
+ int i, n;
+
+ if (len < 4)
+ return -1;
if (result) {
- result->bits = 0;
- for (i=0; i<4; i++)
- result->bits = (result->bits << 8) + *p++;
+ result->bits = 0;
+ for (i = 0; i < 4; i++)
+ result->bits = (result->bits << 8) + *p++;
} else
- p += 4;
+ p += 4;
+
+ len -= 4;
/*
* order=0 means exponent then modulus (the keys sent by the
* stored in a keyfile).
*/
- if (order == 0)
- p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
- if (result)
- result->bytes = (((p[0] << 8) + p[1]) + 7) / 8;
- if (keystr) *keystr = p+2;
- p += ssh1_read_bignum(p, result ? &result->modulus : NULL);
- if (order == 1)
- p += ssh1_read_bignum(p, result ? &result->exponent : NULL);
+ if (order == 0) {
+ n = ssh1_read_bignum(p, len, result ? &result->exponent : NULL);
+ if (n < 0) return -1;
+ p += n;
+ len -= n;
+ }
+ n = ssh1_read_bignum(p, len, result ? &result->modulus : NULL);
+ if (n < 0 || (result && bignum_bitcount(result->modulus) == 0)) return -1;
+ if (result)
+ result->bytes = n - 2;
+ if (keystr)
+ *keystr = p + 2;
+ p += n;
+ len -= n;
+
+ if (order == 1) {
+ n = ssh1_read_bignum(p, len, result ? &result->exponent : NULL);
+ if (n < 0) return -1;
+ p += n;
+ len -= n;
+ }
return p - data;
}
-int makeprivate(unsigned char *data, struct RSAKey *result) {
- return ssh1_read_bignum(data, &result->private_exponent);
+int makeprivate(unsigned char *data, int len, struct RSAKey *result)
+{
+ return ssh1_read_bignum(data, len, &result->private_exponent);
}
-void rsaencrypt(unsigned char *data, int length, struct RSAKey *key) {
+int rsaencrypt(unsigned char *data, int length, struct RSAKey *key)
+{
Bignum b1, b2;
int i;
unsigned char *p;
- memmove(data+key->bytes-length, data, length);
+ if (key->bytes < length + 4)
+ return 0; /* RSA key too short! */
+
+ memmove(data + key->bytes - length, data, length);
data[0] = 0;
data[1] = 2;
- for (i = 2; i < key->bytes-length-1; i++) {
+ for (i = 2; i < key->bytes - length - 1; i++) {
do {
data[i] = random_byte();
} while (data[i] == 0);
}
- data[key->bytes-length-1] = 0;
+ data[key->bytes - length - 1] = 0;
b1 = bignum_from_bytes(data, key->bytes);
b2 = modpow(b1, key->exponent, key->modulus);
p = data;
- for (i=key->bytes; i-- ;) {
- *p++ = bignum_byte(b2, i);
+ for (i = key->bytes; i--;) {
+ *p++ = bignum_byte(b2, i);
}
freebn(b1);
freebn(b2);
+
+ return 1;
}
-Bignum rsadecrypt(Bignum input, struct RSAKey *key) {
+static void sha512_mpint(SHA512_State * s, Bignum b)
+{
+ unsigned char lenbuf[4];
+ int len;
+ len = (bignum_bitcount(b) + 8) / 8;
+ PUT_32BIT(lenbuf, len);
+ SHA512_Bytes(s, lenbuf, 4);
+ while (len-- > 0) {
+ lenbuf[0] = bignum_byte(b, len);
+ SHA512_Bytes(s, lenbuf, 1);
+ }
+ memset(lenbuf, 0, sizeof(lenbuf));
+}
+
+/*
+ * This function is a wrapper on modpow(). It has the same effect
+ * as modpow(), but employs RSA blinding to protect against timing
+ * attacks.
+ */
+static Bignum rsa_privkey_op(Bignum input, struct RSAKey *key)
+{
+ Bignum random, random_encrypted, random_inverse;
+ Bignum input_blinded, ret_blinded;
Bignum ret;
- ret = modpow(input, key->private_exponent, key->modulus);
+
+ SHA512_State ss;
+ unsigned char digest512[64];
+ int digestused = lenof(digest512);
+ int hashseq = 0;
+
+ /*
+ * Start by inventing a random number chosen uniformly from the
+ * range 2..modulus-1. (We do this by preparing a random number
+ * of the right length and retrying if it's greater than the
+ * modulus, to prevent any potential Bleichenbacher-like
+ * attacks making use of the uneven distribution within the
+ * range that would arise from just reducing our number mod n.
+ * There are timing implications to the potential retries, of
+ * course, but all they tell you is the modulus, which you
+ * already knew.)
+ *
+ * To preserve determinism and avoid Pageant needing to share
+ * the random number pool, we actually generate this `random'
+ * number by hashing stuff with the private key.
+ */
+ while (1) {
+ int bits, byte, bitsleft, v;
+ random = copybn(key->modulus);
+ /*
+ * Find the topmost set bit. (This function will return its
+ * index plus one.) Then we'll set all bits from that one
+ * downwards randomly.
+ */
+ bits = bignum_bitcount(random);
+ byte = 0;
+ bitsleft = 0;
+ while (bits--) {
+ if (bitsleft <= 0) {
+ bitsleft = 8;
+ /*
+ * Conceptually the following few lines are equivalent to
+ * byte = random_byte();
+ */
+ if (digestused >= lenof(digest512)) {
+ unsigned char seqbuf[4];
+ PUT_32BIT(seqbuf, hashseq);
+ SHA512_Init(&ss);
+ SHA512_Bytes(&ss, "RSA deterministic blinding", 26);
+ SHA512_Bytes(&ss, seqbuf, sizeof(seqbuf));
+ sha512_mpint(&ss, key->private_exponent);
+ SHA512_Final(&ss, digest512);
+ hashseq++;
+
+ /*
+ * Now hash that digest plus the signature
+ * input.
+ */
+ SHA512_Init(&ss);
+ SHA512_Bytes(&ss, digest512, sizeof(digest512));
+ sha512_mpint(&ss, input);
+ SHA512_Final(&ss, digest512);
+
+ digestused = 0;
+ }
+ byte = digest512[digestused++];
+ }
+ v = byte & 1;
+ byte >>= 1;
+ bitsleft--;
+ bignum_set_bit(random, bits, v);
+ }
+
+ /*
+ * Now check that this number is strictly greater than
+ * zero, and strictly less than modulus.
+ */
+ if (bignum_cmp(random, Zero) <= 0 ||
+ bignum_cmp(random, key->modulus) >= 0) {
+ freebn(random);
+ continue;
+ } else {
+ break;
+ }
+ }
+
+ /*
+ * RSA blinding relies on the fact that (xy)^d mod n is equal
+ * to (x^d mod n) * (y^d mod n) mod n. We invent a random pair
+ * y and y^d; then we multiply x by y, raise to the power d mod
+ * n as usual, and divide by y^d to recover x^d. Thus an
+ * attacker can't correlate the timing of the modpow with the
+ * input, because they don't know anything about the number
+ * that was input to the actual modpow.
+ *
+ * The clever bit is that we don't have to do a huge modpow to
+ * get y and y^d; we will use the number we just invented as
+ * _y^d_, and use the _public_ exponent to compute (y^d)^e = y
+ * from it, which is much faster to do.
+ */
+ random_encrypted = modpow(random, key->exponent, key->modulus);
+ random_inverse = modinv(random, key->modulus);
+ input_blinded = modmul(input, random_encrypted, key->modulus);
+ ret_blinded = modpow(input_blinded, key->private_exponent, key->modulus);
+ ret = modmul(ret_blinded, random_inverse, key->modulus);
+
+ freebn(ret_blinded);
+ freebn(input_blinded);
+ freebn(random_inverse);
+ freebn(random_encrypted);
+ freebn(random);
+
return ret;
}
-int rsastr_len(struct RSAKey *key) {
+Bignum rsadecrypt(Bignum input, struct RSAKey *key)
+{
+ return rsa_privkey_op(input, key);
+}
+
+int rsastr_len(struct RSAKey *key)
+{
Bignum md, ex;
int mdlen, exlen;
md = key->modulus;
ex = key->exponent;
- mdlen = (ssh1_bignum_bitcount(md)+15) / 16;
- exlen = (ssh1_bignum_bitcount(ex)+15) / 16;
- return 4 * (mdlen+exlen) + 20;
+ mdlen = (bignum_bitcount(md) + 15) / 16;
+ exlen = (bignum_bitcount(ex) + 15) / 16;
+ return 4 * (mdlen + exlen) + 20;
}
-void rsastr_fmt(char *str, struct RSAKey *key) {
+void rsastr_fmt(char *str, struct RSAKey *key)
+{
Bignum md, ex;
int len = 0, i, nibbles;
static const char hex[] = "0123456789abcdef";
md = key->modulus;
ex = key->exponent;
- len += sprintf(str+len, "0x");
+ len += sprintf(str + len, "0x");
- nibbles = (3 + ssh1_bignum_bitcount(ex))/4; if (nibbles<1) nibbles=1;
- for (i=nibbles; i-- ;)
- str[len++] = hex[(bignum_byte(ex, i/2) >> (4*(i%2))) & 0xF];
+ nibbles = (3 + bignum_bitcount(ex)) / 4;
+ if (nibbles < 1)
+ nibbles = 1;
+ for (i = nibbles; i--;)
+ str[len++] = hex[(bignum_byte(ex, i / 2) >> (4 * (i % 2))) & 0xF];
- len += sprintf(str+len, ",0x");
+ len += sprintf(str + len, ",0x");
- nibbles = (3 + ssh1_bignum_bitcount(md))/4; if (nibbles<1) nibbles=1;
- for (i=nibbles; i-- ;)
- str[len++] = hex[(bignum_byte(md, i/2) >> (4*(i%2))) & 0xF];
+ nibbles = (3 + bignum_bitcount(md)) / 4;
+ if (nibbles < 1)
+ nibbles = 1;
+ for (i = nibbles; i--;)
+ str[len++] = hex[(bignum_byte(md, i / 2) >> (4 * (i % 2))) & 0xF];
str[len] = '\0';
}
* Generate a fingerprint string for the key. Compatible with the
* OpenSSH fingerprint code.
*/
-void rsa_fingerprint(char *str, int len, struct RSAKey *key) {
+void rsa_fingerprint(char *str, int len, struct RSAKey *key)
+{
struct MD5Context md5c;
unsigned char digest[16];
- char buffer[16*3+40];
+ char buffer[16 * 3 + 40];
int numlen, slen, i;
MD5Init(&md5c);
numlen = ssh1_bignum_length(key->modulus) - 2;
- for (i = numlen; i-- ;) {
- unsigned char c = bignum_byte(key->modulus, i);
- MD5Update(&md5c, &c, 1);
+ for (i = numlen; i--;) {
+ unsigned char c = bignum_byte(key->modulus, i);
+ MD5Update(&md5c, &c, 1);
}
numlen = ssh1_bignum_length(key->exponent) - 2;
- for (i = numlen; i-- ;) {
- unsigned char c = bignum_byte(key->exponent, i);
- MD5Update(&md5c, &c, 1);
+ for (i = numlen; i--;) {
+ unsigned char c = bignum_byte(key->exponent, i);
+ MD5Update(&md5c, &c, 1);
}
MD5Final(digest, &md5c);
- sprintf(buffer, "%d ", ssh1_bignum_bitcount(key->modulus));
+ sprintf(buffer, "%d ", bignum_bitcount(key->modulus));
for (i = 0; i < 16; i++)
- sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
- strncpy(str, buffer, len); str[len-1] = '\0';
+ sprintf(buffer + strlen(buffer), "%s%02x", i ? ":" : "",
+ digest[i]);
+ strncpy(str, buffer, len);
+ str[len - 1] = '\0';
slen = strlen(str);
- if (key->comment && slen < len-1) {
- str[slen] = ' ';
- strncpy(str+slen+1, key->comment, len-slen-1);
- str[len-1] = '\0';
+ if (key->comment && slen < len - 1) {
+ str[slen] = ' ';
+ strncpy(str + slen + 1, key->comment, len - slen - 1);
+ str[len - 1] = '\0';
}
}
-void freersakey(struct RSAKey *key) {
- if (key->modulus) freebn(key->modulus);
- if (key->exponent) freebn(key->exponent);
- if (key->private_exponent) freebn(key->private_exponent);
- if (key->comment) sfree(key->comment);
+/*
+ * Verify that the public data in an RSA key matches the private
+ * data. We also check the private data itself: we ensure that p >
+ * q and that iqmp really is the inverse of q mod p.
+ */
+int rsa_verify(struct RSAKey *key)
+{
+ Bignum n, ed, pm1, qm1;
+ int cmp;
+
+ /* n must equal pq. */
+ n = bigmul(key->p, key->q);
+ cmp = bignum_cmp(n, key->modulus);
+ freebn(n);
+ if (cmp != 0)
+ return 0;
+
+ /* e * d must be congruent to 1, modulo (p-1) and modulo (q-1). */
+ pm1 = copybn(key->p);
+ decbn(pm1);
+ ed = modmul(key->exponent, key->private_exponent, pm1);
+ cmp = bignum_cmp(ed, One);
+ sfree(ed);
+ if (cmp != 0)
+ return 0;
+
+ qm1 = copybn(key->q);
+ decbn(qm1);
+ ed = modmul(key->exponent, key->private_exponent, qm1);
+ cmp = bignum_cmp(ed, One);
+ sfree(ed);
+ if (cmp != 0)
+ return 0;
+
+ /*
+ * Ensure p > q.
+ */
+ if (bignum_cmp(key->p, key->q) <= 0)
+ return 0;
+
+ /*
+ * Ensure iqmp * q is congruent to 1, modulo p.
+ */
+ n = modmul(key->iqmp, key->q, key->p);
+ cmp = bignum_cmp(n, One);
+ sfree(n);
+ if (cmp != 0)
+ return 0;
+
+ return 1;
+}
+
+/* Public key blob as used by Pageant: exponent before modulus. */
+unsigned char *rsa_public_blob(struct RSAKey *key, int *len)
+{
+ int length, pos;
+ unsigned char *ret;
+
+ length = (ssh1_bignum_length(key->modulus) +
+ ssh1_bignum_length(key->exponent) + 4);
+ ret = snewn(length, unsigned char);
+
+ PUT_32BIT(ret, bignum_bitcount(key->modulus));
+ pos = 4;
+ pos += ssh1_write_bignum(ret + pos, key->exponent);
+ pos += ssh1_write_bignum(ret + pos, key->modulus);
+
+ *len = length;
+ return ret;
+}
+
+/* Given a public blob, determine its length. */
+int rsa_public_blob_len(void *data, int maxlen)
+{
+ unsigned char *p = (unsigned char *)data;
+ int n;
+
+ if (maxlen < 4)
+ return -1;
+ p += 4; /* length word */
+ maxlen -= 4;
+
+ n = ssh1_read_bignum(p, maxlen, NULL); /* exponent */
+ if (n < 0)
+ return -1;
+ p += n;
+
+ n = ssh1_read_bignum(p, maxlen, NULL); /* modulus */
+ if (n < 0)
+ return -1;
+ p += n;
+
+ return p - (unsigned char *)data;
+}
+
+void freersakey(struct RSAKey *key)
+{
+ if (key->modulus)
+ freebn(key->modulus);
+ if (key->exponent)
+ freebn(key->exponent);
+ if (key->private_exponent)
+ freebn(key->private_exponent);
+ if (key->comment)
+ sfree(key->comment);
}
/* ----------------------------------------------------------------------
* Implementation of the ssh-rsa signing key type.
*/
-#define GET_32BIT(cp) \
- (((unsigned long)(unsigned char)(cp)[0] << 24) | \
- ((unsigned long)(unsigned char)(cp)[1] << 16) | \
- ((unsigned long)(unsigned char)(cp)[2] << 8) | \
- ((unsigned long)(unsigned char)(cp)[3]))
-
-#define PUT_32BIT(cp, value) { \
- (cp)[0] = (unsigned char)((value) >> 24); \
- (cp)[1] = (unsigned char)((value) >> 16); \
- (cp)[2] = (unsigned char)((value) >> 8); \
- (cp)[3] = (unsigned char)(value); }
-
-static void getstring(char **data, int *datalen, char **p, int *length) {
+static void getstring(char **data, int *datalen, char **p, int *length)
+{
*p = NULL;
if (*datalen < 4)
- return;
+ return;
*length = GET_32BIT(*data);
- *datalen -= 4; *data += 4;
+ *datalen -= 4;
+ *data += 4;
if (*datalen < *length)
- return;
+ return;
*p = *data;
- *data += *length; *datalen -= *length;
+ *data += *length;
+ *datalen -= *length;
}
-static Bignum getmp(char **data, int *datalen) {
+static Bignum getmp(char **data, int *datalen)
+{
char *p;
int length;
Bignum b;
getstring(data, datalen, &p, &length);
if (!p)
- return NULL;
- b = bignum_from_bytes(p, length);
+ return NULL;
+ b = bignum_from_bytes((unsigned char *)p, length);
return b;
}
-static void *rsa2_newkey(char *data, int len) {
+static void *rsa2_newkey(char *data, int len)
+{
char *p;
int slen;
struct RSAKey *rsa;
- rsa = smalloc(sizeof(struct RSAKey));
- if (!rsa) return NULL;
+ rsa = snew(struct RSAKey);
+ if (!rsa)
+ return NULL;
getstring(&data, &len, &p, &slen);
if (!p || slen != 7 || memcmp(p, "ssh-rsa", 7)) {
return rsa;
}
-static void rsa2_freekey(void *key) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static void rsa2_freekey(void *key)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
freersakey(rsa);
sfree(rsa);
}
-static char *rsa2_fmtkey(void *key) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static char *rsa2_fmtkey(void *key)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
char *p;
int len;
-
+
len = rsastr_len(rsa);
- p = smalloc(len);
+ p = snewn(len, char);
rsastr_fmt(p, rsa);
return p;
}
-static unsigned char *rsa2_public_blob(void *key, int *len) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static unsigned char *rsa2_public_blob(void *key, int *len)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
int elen, mlen, bloblen;
int i;
unsigned char *blob, *p;
- elen = (ssh1_bignum_bitcount(rsa->exponent)+8)/8;
- mlen = (ssh1_bignum_bitcount(rsa->modulus)+8)/8;
+ elen = (bignum_bitcount(rsa->exponent) + 8) / 8;
+ mlen = (bignum_bitcount(rsa->modulus) + 8) / 8;
/*
* string "ssh-rsa", mpint exp, mpint mod. Total 19+elen+mlen.
* (three length fields, 12+7=19).
*/
- bloblen = 19+elen+mlen;
- blob = smalloc(bloblen);
+ bloblen = 19 + elen + mlen;
+ blob = snewn(bloblen, unsigned char);
p = blob;
- PUT_32BIT(p, 7); p += 4;
- memcpy(p, "ssh-rsa", 7); p += 7;
- PUT_32BIT(p, elen); p += 4;
- for (i = elen; i-- ;) *p++ = bignum_byte(rsa->exponent, i);
- PUT_32BIT(p, mlen); p += 4;
- for (i = mlen; i-- ;) *p++ = bignum_byte(rsa->modulus, i);
+ PUT_32BIT(p, 7);
+ p += 4;
+ memcpy(p, "ssh-rsa", 7);
+ p += 7;
+ PUT_32BIT(p, elen);
+ p += 4;
+ for (i = elen; i--;)
+ *p++ = bignum_byte(rsa->exponent, i);
+ PUT_32BIT(p, mlen);
+ p += 4;
+ for (i = mlen; i--;)
+ *p++ = bignum_byte(rsa->modulus, i);
assert(p == blob + bloblen);
*len = bloblen;
return blob;
}
-static unsigned char *rsa2_private_blob(void *key, int *len) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static unsigned char *rsa2_private_blob(void *key, int *len)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
int dlen, plen, qlen, ulen, bloblen;
int i;
unsigned char *blob, *p;
- dlen = (ssh1_bignum_bitcount(rsa->private_exponent)+8)/8;
- plen = (ssh1_bignum_bitcount(rsa->p)+8)/8;
- qlen = (ssh1_bignum_bitcount(rsa->q)+8)/8;
- ulen = (ssh1_bignum_bitcount(rsa->iqmp)+8)/8;
+ dlen = (bignum_bitcount(rsa->private_exponent) + 8) / 8;
+ plen = (bignum_bitcount(rsa->p) + 8) / 8;
+ qlen = (bignum_bitcount(rsa->q) + 8) / 8;
+ ulen = (bignum_bitcount(rsa->iqmp) + 8) / 8;
/*
* mpint private_exp, mpint p, mpint q, mpint iqmp. Total 16 +
* sum of lengths.
*/
- bloblen = 16+dlen+plen+qlen+ulen;
- blob = smalloc(bloblen);
+ bloblen = 16 + dlen + plen + qlen + ulen;
+ blob = snewn(bloblen, unsigned char);
p = blob;
- PUT_32BIT(p, dlen); p += 4;
- for (i = dlen; i-- ;) *p++ = bignum_byte(rsa->private_exponent, i);
- PUT_32BIT(p, plen); p += 4;
- for (i = plen; i-- ;) *p++ = bignum_byte(rsa->p, i);
- PUT_32BIT(p, qlen); p += 4;
- for (i = qlen; i-- ;) *p++ = bignum_byte(rsa->q, i);
- PUT_32BIT(p, ulen); p += 4;
- for (i = ulen; i-- ;) *p++ = bignum_byte(rsa->iqmp, i);
+ PUT_32BIT(p, dlen);
+ p += 4;
+ for (i = dlen; i--;)
+ *p++ = bignum_byte(rsa->private_exponent, i);
+ PUT_32BIT(p, plen);
+ p += 4;
+ for (i = plen; i--;)
+ *p++ = bignum_byte(rsa->p, i);
+ PUT_32BIT(p, qlen);
+ p += 4;
+ for (i = qlen; i--;)
+ *p++ = bignum_byte(rsa->q, i);
+ PUT_32BIT(p, ulen);
+ p += 4;
+ for (i = ulen; i--;)
+ *p++ = bignum_byte(rsa->iqmp, i);
assert(p == blob + bloblen);
*len = bloblen;
return blob;
}
static void *rsa2_createkey(unsigned char *pub_blob, int pub_len,
- unsigned char *priv_blob, int priv_len) {
+ unsigned char *priv_blob, int priv_len)
+{
struct RSAKey *rsa;
- char *pb = (char *)priv_blob;
-
- rsa = rsa2_newkey((char *)pub_blob, pub_len);
+ char *pb = (char *) priv_blob;
+
+ rsa = rsa2_newkey((char *) pub_blob, pub_len);
rsa->private_exponent = getmp(&pb, &priv_len);
rsa->p = getmp(&pb, &priv_len);
rsa->q = getmp(&pb, &priv_len);
rsa->iqmp = getmp(&pb, &priv_len);
+ if (!rsa_verify(rsa)) {
+ rsa2_freekey(rsa);
+ return NULL;
+ }
+
return rsa;
}
-static void *rsa2_openssh_createkey(unsigned char **blob, int *len) {
- char **b = (char **)blob;
+static void *rsa2_openssh_createkey(unsigned char **blob, int *len)
+{
+ char **b = (char **) blob;
struct RSAKey *rsa;
- char *p;
- int slen;
- rsa = smalloc(sizeof(struct RSAKey));
- if (!rsa) return NULL;
+ rsa = snew(struct RSAKey);
+ if (!rsa)
+ return NULL;
rsa->comment = NULL;
rsa->modulus = getmp(b, len);
return rsa;
}
-static char *rsa2_fingerprint(void *key) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static int rsa2_openssh_fmtkey(void *key, unsigned char *blob, int len)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
+ int bloblen, i;
+
+ bloblen =
+ ssh2_bignum_length(rsa->modulus) +
+ ssh2_bignum_length(rsa->exponent) +
+ ssh2_bignum_length(rsa->private_exponent) +
+ ssh2_bignum_length(rsa->iqmp) +
+ ssh2_bignum_length(rsa->p) + ssh2_bignum_length(rsa->q);
+
+ if (bloblen > len)
+ return bloblen;
+
+ bloblen = 0;
+#define ENC(x) \
+ PUT_32BIT(blob+bloblen, ssh2_bignum_length((x))-4); bloblen += 4; \
+ for (i = ssh2_bignum_length((x))-4; i-- ;) blob[bloblen++]=bignum_byte((x),i);
+ ENC(rsa->modulus);
+ ENC(rsa->exponent);
+ ENC(rsa->private_exponent);
+ ENC(rsa->iqmp);
+ ENC(rsa->p);
+ ENC(rsa->q);
+
+ return bloblen;
+}
+
+static int rsa2_pubkey_bits(void *blob, int len)
+{
+ struct RSAKey *rsa;
+ int ret;
+
+ rsa = rsa2_newkey((char *) blob, len);
+ ret = bignum_bitcount(rsa->modulus);
+ rsa2_freekey(rsa);
+
+ return ret;
+}
+
+static char *rsa2_fingerprint(void *key)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
struct MD5Context md5c;
unsigned char digest[16], lenbuf[4];
- char buffer[16*3+40];
+ char buffer[16 * 3 + 40];
char *ret;
int numlen, i;
MD5Init(&md5c);
- MD5Update(&md5c, "\0\0\0\7ssh-rsa", 11);
+ MD5Update(&md5c, (unsigned char *)"\0\0\0\7ssh-rsa", 11);
#define ADD_BIGNUM(bignum) \
- numlen = (ssh1_bignum_bitcount(bignum)+8)/8; \
+ numlen = (bignum_bitcount(bignum)+8)/8; \
PUT_32BIT(lenbuf, numlen); MD5Update(&md5c, lenbuf, 4); \
for (i = numlen; i-- ;) { \
unsigned char c = bignum_byte(bignum, i); \
MD5Final(digest, &md5c);
- sprintf(buffer, "ssh-rsa %d ", ssh1_bignum_bitcount(rsa->modulus));
+ sprintf(buffer, "ssh-rsa %d ", bignum_bitcount(rsa->modulus));
for (i = 0; i < 16; i++)
- sprintf(buffer+strlen(buffer), "%s%02x", i?":":"", digest[i]);
- ret = smalloc(strlen(buffer)+1);
+ sprintf(buffer + strlen(buffer), "%s%02x", i ? ":" : "",
+ digest[i]);
+ ret = snewn(strlen(buffer) + 1, char);
if (ret)
- strcpy(ret, buffer);
+ strcpy(ret, buffer);
return ret;
}
/*
* This is the magic ASN.1/DER prefix that goes in the decoded
* signature, between the string of FFs and the actual SHA hash
- * value. As closely as I can tell, the meaning of it is:
+ * value. The meaning of it is:
*
* 00 -- this marks the end of the FFs; not part of the ASN.1 bit itself
*
* 30 21 -- a constructed SEQUENCE of length 0x21
* 30 09 -- a constructed sub-SEQUENCE of length 9
* 06 05 -- an object identifier, length 5
- * 2B 0E 03 02 1A --
+ * 2B 0E 03 02 1A -- object id { 1 3 14 3 2 26 }
+ * (the 1,3 comes from 0x2B = 43 = 40*1+3)
* 05 00 -- NULL
* 04 14 -- a primitive OCTET STRING of length 0x14
* [0x14 bytes of hash data follows]
+ *
+ * The object id in the middle there is listed as `id-sha1' in
+ * ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1d2.asn (the
+ * ASN module for PKCS #1) and its expanded form is as follows:
+ *
+ * id-sha1 OBJECT IDENTIFIER ::= {
+ * iso(1) identified-organization(3) oiw(14) secsig(3)
+ * algorithms(2) 26 }
*/
-static unsigned char asn1_weird_stuff[] = {
- 0x00,0x30,0x21,0x30,0x09,0x06,0x05,0x2B,
- 0x0E,0x03,0x02,0x1A,0x05,0x00,0x04,0x14,
+static const unsigned char asn1_weird_stuff[] = {
+ 0x00, 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2B,
+ 0x0E, 0x03, 0x02, 0x1A, 0x05, 0x00, 0x04, 0x14,
};
+#define ASN1_LEN ( (int) sizeof(asn1_weird_stuff) )
+
static int rsa2_verifysig(void *key, char *sig, int siglen,
- char *data, int datalen) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+ char *data, int datalen)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
Bignum in, out;
char *p;
int slen;
getstring(&sig, &siglen, &p, &slen);
if (!p || slen != 7 || memcmp(p, "ssh-rsa", 7)) {
- return 0;
+ return 0;
}
in = getmp(&sig, &siglen);
out = modpow(in, rsa->exponent, rsa->modulus);
ret = 1;
- bytes = ssh1_bignum_bitcount(rsa->modulus) / 8;
+ bytes = (bignum_bitcount(rsa->modulus)+7) / 8;
/* Top (partial) byte should be zero. */
- if (bignum_byte(out, bytes-1) != 0)
- ret = 0;
+ if (bignum_byte(out, bytes - 1) != 0)
+ ret = 0;
/* First whole byte should be 1. */
- if (bignum_byte(out, bytes-2) != 1)
- ret = 0;
+ if (bignum_byte(out, bytes - 2) != 1)
+ ret = 0;
/* Most of the rest should be FF. */
- for (i = bytes-3; i >= 20 + sizeof(asn1_weird_stuff); i--) {
- if (bignum_byte(out, i) != 0xFF)
- ret = 0;
+ for (i = bytes - 3; i >= 20 + ASN1_LEN; i--) {
+ if (bignum_byte(out, i) != 0xFF)
+ ret = 0;
}
/* Then we expect to see the asn1_weird_stuff. */
- for (i = 20 + sizeof(asn1_weird_stuff) - 1, j=0; i >= 20; i--,j++) {
- if (bignum_byte(out, i) != asn1_weird_stuff[j])
- ret = 0;
+ for (i = 20 + ASN1_LEN - 1, j = 0; i >= 20; i--, j++) {
+ if (bignum_byte(out, i) != asn1_weird_stuff[j])
+ ret = 0;
}
/* Finally, we expect to see the SHA-1 hash of the signed data. */
SHA_Simple(data, datalen, hash);
- for (i = 19, j=0; i >= 0; i--,j++) {
- if (bignum_byte(out, i) != hash[j])
- ret = 0;
+ for (i = 19, j = 0; i >= 0; i--, j++) {
+ if (bignum_byte(out, i) != hash[j])
+ ret = 0;
}
+ freebn(out);
return ret;
}
-unsigned char *rsa2_sign(void *key, char *data, int datalen, int *siglen) {
- struct RSAKey *rsa = (struct RSAKey *)key;
+static unsigned char *rsa2_sign(void *key, char *data, int datalen,
+ int *siglen)
+{
+ struct RSAKey *rsa = (struct RSAKey *) key;
unsigned char *bytes;
int nbytes;
unsigned char hash[20];
SHA_Simple(data, datalen, hash);
- nbytes = (ssh1_bignum_bitcount(rsa->modulus)-1) / 8;
- bytes = smalloc(nbytes);
+ nbytes = (bignum_bitcount(rsa->modulus) - 1) / 8;
+ assert(1 <= nbytes - 20 - ASN1_LEN);
+ bytes = snewn(nbytes, unsigned char);
bytes[0] = 1;
- for (i = 1; i < nbytes-20-sizeof(asn1_weird_stuff); i++)
+ for (i = 1; i < nbytes - 20 - ASN1_LEN; i++)
bytes[i] = 0xFF;
- for (i = nbytes-20-sizeof(asn1_weird_stuff), j=0; i < nbytes-20; i++,j++)
+ for (i = nbytes - 20 - ASN1_LEN, j = 0; i < nbytes - 20; i++, j++)
bytes[i] = asn1_weird_stuff[j];
- for (i = nbytes-20, j=0; i < nbytes; i++,j++)
+ for (i = nbytes - 20, j = 0; i < nbytes; i++, j++)
bytes[i] = hash[j];
in = bignum_from_bytes(bytes, nbytes);
sfree(bytes);
- out = modpow(in, rsa->private_exponent, rsa->modulus);
+ out = rsa_privkey_op(in, rsa);
freebn(in);
- nbytes = (ssh1_bignum_bitcount(out)+7)/8;
- bytes = smalloc(4+7+4+nbytes);
+ nbytes = (bignum_bitcount(out) + 7) / 8;
+ bytes = snewn(4 + 7 + 4 + nbytes, unsigned char);
PUT_32BIT(bytes, 7);
- memcpy(bytes+4, "ssh-rsa", 7);
- PUT_32BIT(bytes+4+7, nbytes);
+ memcpy(bytes + 4, "ssh-rsa", 7);
+ PUT_32BIT(bytes + 4 + 7, nbytes);
for (i = 0; i < nbytes; i++)
- bytes[4+7+4+i] = bignum_byte(out, nbytes-1-i);
+ bytes[4 + 7 + 4 + i] = bignum_byte(out, nbytes - 1 - i);
freebn(out);
- *siglen = 4+7+4+nbytes;
+ *siglen = 4 + 7 + 4 + nbytes;
return bytes;
}
rsa2_private_blob,
rsa2_createkey,
rsa2_openssh_createkey,
+ rsa2_openssh_fmtkey,
+ rsa2_pubkey_bits,
rsa2_fingerprint,
rsa2_verifysig,
rsa2_sign,
projects / u / mdw / putty / blobdiff