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Add support for DSA authentication in SSH2, following clever ideas

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on how to get round the problem of generating a good k.

[originally from svn r1284]
This commit is contained in:
Simon Tatham
2001-09-22 20:52:21 +00:00
parent 486685c89a
commit d345ebc2a5
11 changed files with 749 additions and 263 deletions
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68
sshbn.c
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@ -6,13 +6,7 @@
#include <stdlib.h>
#include <string.h>
#if 0 // use PuTTY main debugging for diagbn()
#include <windows.h>
#include "putty.h"
#define debugprint debug
#else
#define debugprint(x) printf x
#endif
#include "misc.h"
#define BIGNUM_INTERNAL
typedef unsigned short *Bignum;
@ -409,9 +403,10 @@ Bignum modmul(Bignum p, Bignum q, Bignum mod)
* Compute p % mod.
* The most significant word of mod MUST be non-zero.
* We assume that the result array is the same size as the mod array.
* We optionally write out a quotient.
* We optionally write out a quotient if `quotient' is non-NULL.
* We can avoid writing out the result if `result' is NULL.
*/
void bigmod(Bignum p, Bignum mod, Bignum result, Bignum quotient)
void bigdivmod(Bignum p, Bignum mod, Bignum result, Bignum quotient)
{
unsigned short *n, *m;
int mshift;
@ -460,9 +455,11 @@ void bigmod(Bignum p, Bignum mod, Bignum result, Bignum quotient)
}
/* Copy result to buffer */
for (i = 1; i <= result[0]; i++) {
int j = plen - i;
result[i] = j >= 0 ? n[j] : 0;
if (result) {
for (i = 1; i <= result[0]; i++) {
int j = plen - i;
result[i] = j >= 0 ? n[j] : 0;
}
}
/* Free temporary arrays */
@ -749,16 +746,17 @@ Bignum bignum_bitmask(Bignum n)
}
/*
* Convert a (max 16-bit) short into a bignum.
* Convert a (max 32-bit) long into a bignum.
*/
Bignum bignum_from_short(unsigned short n)
Bignum bignum_from_long(unsigned long n)
{
Bignum ret;
ret = newbn(2);
ret = newbn(3);
ret[1] = n & 0xFFFF;
ret[2] = (n >> 16) & 0xFFFF;
ret[0] = (ret[2] ? 2 : 1);
ret[3] = 0;
ret[0] = (ret[2] ? 2 : 1);
return ret;
}
@ -804,21 +802,40 @@ void diagbn(char *prefix, Bignum md)
int i, nibbles, morenibbles;
static const char hex[] = "0123456789ABCDEF";
debugprint(("%s0x", prefix ? prefix : ""));
debug(("%s0x", prefix ? prefix : ""));
nibbles = (3 + bignum_bitcount(md)) / 4;
if (nibbles < 1)
nibbles = 1;
morenibbles = 4 * md[0] - nibbles;
for (i = 0; i < morenibbles; i++)
debugprint(("-"));
debug(("-"));
for (i = nibbles; i--;)
debugprint(
("%c",
hex[(bignum_byte(md, i / 2) >> (4 * (i % 2))) & 0xF]));
debug(("%c",
hex[(bignum_byte(md, i / 2) >> (4 * (i % 2))) & 0xF]));
if (prefix)
debugprint(("\n"));
debug(("\n"));
}
/*
* Simple division.
*/
Bignum bigdiv(Bignum a, Bignum b)
{
Bignum q = newbn(a[0]);
bigdivmod(a, b, NULL, q);
return q;
}
/*
* Simple remainder.
*/
Bignum bigmod(Bignum a, Bignum b)
{
Bignum r = newbn(b[0]);
bigdivmod(a, b, r, NULL);
return r;
}
/*
@ -829,12 +846,9 @@ Bignum biggcd(Bignum av, Bignum bv)
Bignum a = copybn(av);
Bignum b = copybn(bv);
diagbn("a = ", a);
diagbn("b = ", b);
while (bignum_cmp(b, Zero) != 0) {
Bignum t = newbn(b[0]);
bigmod(a, b, t, NULL);
diagbn("t = ", t);
bigdivmod(a, b, t, NULL);
while (t[0] > 1 && t[t[0]] == 0)
t[0]--;
freebn(a);
@ -860,7 +874,7 @@ Bignum modinv(Bignum number, Bignum modulus)
while (bignum_cmp(b, One) != 0) {
Bignum t = newbn(b[0]);
Bignum q = newbn(a[0]);
bigmod(a, b, t, q);
bigdivmod(a, b, t, q);
while (t[0] > 1 && t[t[0]] == 0)
t[0]--;
freebn(a);