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Upgrade to openssl-1-1-1 #16

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Upgrade to openssl-1-1-1 #16

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e289bd4
DES_xxx upgrade, need to fix SHA_xxx now
gwbres Feb 27, 2021
d64ba81
upgrading to openssl-1.1
gwbres Feb 27, 2021
ceadba2
upgraded bn contexts to openssl-1.1
gwbres Feb 27, 2021
d02e556
removed non needed include
gwbres Feb 27, 2021
57d7b89
added missing binary to gitignore
gwbres Feb 27, 2021
fe08d11
added context for host BN
gwbres Feb 27, 2021
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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -32,3 +32,4 @@ tcpkill
tcpnice
urlsnarf
webmitm
webspy
82 changes: 61 additions & 21 deletions ssh.c
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Expand Up @@ -92,7 +92,7 @@ static u_int crc32_tab[] = {
static u_char pkt[4 + 8 + SSH_MAX_PKTLEN];

static void
put_bn(BIGNUM *bn, u_char **pp)
put_bn(const BIGNUM *bn, u_char **pp)
{
short i;

Expand Down Expand Up @@ -122,7 +122,7 @@ get_bn(BIGNUM *bn, u_char **pp, int *lenp)
}

static u_char *
ssh_session_id(u_char *cookie, BIGNUM *hostkey_n, BIGNUM *servkey_n)
ssh_session_id(u_char *cookie, const BIGNUM *hostkey_n, const BIGNUM *servkey_n)
{
static u_char sessid[16];
u_int i, j;
Expand Down Expand Up @@ -233,7 +233,12 @@ SSH_set_fd(SSH *ssh, int fd)
int
SSH_accept(SSH *ssh)
{
const BIGNUM *host_bn_n;
const BIGNUM *host_bn_e;
const BIGNUM *serv_bn_n;
const BIGNUM *serv_bn_e;
BIGNUM *enckey;

u_char *p, cipher, cookie[8], msg[1024];
u_int32_t num;
int i;
Expand All @@ -244,14 +249,19 @@ SSH_accept(SSH *ssh)
/* Send public key. */
p = msg;
*p++ = SSH_SMSG_PUBLIC_KEY; /* type */
memcpy(p, cookie, 8); p += 8; /* cookie */
memcpy(p, cookie, 8); p += 8; /* cookie */
num = 768; PUTLONG(num, p); /* servkey bits */
put_bn(ssh->ctx->servkey->e, &p); /* servkey exponent */
put_bn(ssh->ctx->servkey->n, &p); /* servkey modulus */

RSA_get0_key(ssh->ctx->servkey, &serv_bn_n, &serv_bn_e, NULL);
put_bn(serv_bn_e, &p); /* servkey exponent */
put_bn(serv_bn_n, &p); /* servkey modulus */
num = 1024; PUTLONG(num, p); /* hostkey bits */
put_bn(ssh->ctx->hostkey->e, &p); /* hostkey exponent */
put_bn(ssh->ctx->hostkey->n, &p); /* hostkey modulus */

RSA_get0_key(ssh->ctx->hostkey, &host_bn_n, &host_bn_e, NULL);
put_bn(host_bn_e, &p); /* hostkey exponent */
put_bn(host_bn_n, &p); /* hostkey modulus */
num = 0; PUTLONG(num, p); /* protocol flags */

num = ssh->ctx->encmask; PUTLONG(num, p); /* ciphers */
num = ssh->ctx->authmask; PUTLONG(num, p); /* authmask */

Expand Down Expand Up @@ -301,7 +311,7 @@ SSH_accept(SSH *ssh)
SKIP(p, i, 4);

/* Decrypt session key. */
if (BN_cmp(ssh->ctx->servkey->n, ssh->ctx->hostkey->n) > 0) {
if (BN_cmp(serv_bn_n, host_bn_n) > 0) {
rsa_private_decrypt(enckey, enckey, ssh->ctx->servkey);
rsa_private_decrypt(enckey, enckey, ssh->ctx->hostkey);
}
Expand All @@ -321,8 +331,7 @@ SSH_accept(SSH *ssh)
BN_clear_free(enckey);

/* Derive real session key using session id. */
if ((p = ssh_session_id(cookie, ssh->ctx->hostkey->n,
ssh->ctx->servkey->n)) == NULL) {
if ((p = ssh_session_id(cookie, host_bn_n, serv_bn_n)) == NULL) {
warn("ssh_session_id");
return (-1);
}
Expand Down Expand Up @@ -356,6 +365,14 @@ SSH_accept(SSH *ssh)
int
SSH_connect(SSH *ssh)
{
BN_CTX *serv_bn_ctx;
BIGNUM *serv_bn_e;
BIGNUM *serv_bn_n;

BN_CTX *host_bn_ctx;
BIGNUM *host_bn_e;
BIGNUM *host_bn_n;

BIGNUM *bn;
u_char *p, cipher, cookie[8], msg[1024];
u_int32_t num;
Expand All @@ -382,21 +399,45 @@ SSH_connect(SSH *ssh)

/* Get servkey. */
ssh->ctx->servkey = RSA_new();
ssh->ctx->servkey->n = BN_new();
ssh->ctx->servkey->e = BN_new();

serv_bn_ctx = BN_CTX_new();
if (serv_bn_ctx == NULL)
{
return (-1);
}

BN_CTX_start (serv_bn_ctx);
serv_bn_e = BN_CTX_get(serv_bn_ctx);
serv_bn_n = BN_CTX_get(serv_bn_ctx);
RSA_set0_key(ssh->ctx->servkey, serv_bn_n, serv_bn_n, NULL);

SKIP(p, i, 4);
get_bn(ssh->ctx->servkey->e, &p, &i);
get_bn(ssh->ctx->servkey->n, &p, &i);
get_bn(serv_bn_e, &p, &i);
get_bn(serv_bn_n, &p, &i);

BN_CTX_end (serv_bn_ctx);

/* Get hostkey. */
ssh->ctx->hostkey = RSA_new();
ssh->ctx->hostkey->n = BN_new();
ssh->ctx->hostkey->e = BN_new();

host_bn_ctx = BN_CTX_new();
if (host_bn_ctx == NULL)
{
return (-1);
}

BN_CTX_start (host_bn_ctx);
host_bn_e = BN_CTX_get(host_bn_ctx);
host_bn_n = BN_CTX_get(host_bn_ctx);
RSA_set0_key(ssh->ctx->hostkey, host_bn_n, host_bn_n, NULL);

BN_CTX_end (host_bn_ctx);

SKIP(p, i, 4);
get_bn(ssh->ctx->hostkey->e, &p, &i);
get_bn(ssh->ctx->hostkey->n, &p, &i);
get_bn(host_bn_e, &p, &i);
get_bn(host_bn_n, &p, &i);

BN_CTX_end (host_bn_ctx);

/* Get cipher, auth masks. */
SKIP(p, i, 4);
Expand All @@ -408,8 +449,7 @@ SSH_connect(SSH *ssh)
RAND_bytes(ssh->sesskey, sizeof(ssh->sesskey));

/* Obfuscate with session id. */
if ((p = ssh_session_id(cookie, ssh->ctx->hostkey->n,
ssh->ctx->servkey->n)) == NULL) {
if ((p = ssh_session_id(cookie, host_bn_n, serv_bn_n)) == NULL) {
warn("ssh_session_id");
return (-1);
}
Expand All @@ -425,7 +465,7 @@ SSH_connect(SSH *ssh)
else BN_add_word(bn, ssh->sesskey[i]);
}
/* Encrypt session key. */
if (BN_cmp(ssh->ctx->servkey->n, ssh->ctx->hostkey->n) < 0) {
if (BN_cmp(serv_bn_n, host_bn_n) < 0) {
rsa_public_encrypt(bn, bn, ssh->ctx->servkey);
rsa_public_encrypt(bn, bn, ssh->ctx->hostkey);
}
Expand Down
38 changes: 23 additions & 15 deletions sshcrypto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,8 @@
#include <stdio.h>
#include <stdlib.h>

#include <string.h>

#include "sshcrypto.h"

struct blowfish_state {
Expand All @@ -29,20 +31,23 @@ struct blowfish_state {
};

struct des3_state {
des_key_schedule k1, k2, k3;
des_cblock iv1, iv2, iv3;
DES_key_schedule k1, k2, k3;
DES_cblock iv1, iv2, iv3;
};

void
rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
BIGNUM *bn_e, *bn_n;
u_char *inbuf, *outbuf;
int len, ilen, olen;

if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
RSA_get0_key(key, &bn_n, &bn_e, NULL);

if (BN_num_bits(bn_e) < 2 || !BN_is_odd(bn_e))
errx(1, "rsa_public_encrypt() exponent too small or not odd");

olen = BN_num_bytes(key->n);
olen = BN_num_bytes(bn_n);
outbuf = malloc(olen);

ilen = BN_num_bytes(in);
Expand All @@ -68,10 +73,13 @@ rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
void
rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
BIGNUM *bn_n, *bn_e;
u_char *inbuf, *outbuf;
int len, ilen, olen;

RSA_get0_key(key, &bn_n, &bn_e, NULL);

olen = BN_num_bytes(key->n);
olen = BN_num_bytes(bn_n);
outbuf = malloc(olen);

ilen = BN_num_bytes(in);
Expand Down Expand Up @@ -155,13 +163,13 @@ des3_init(u_char *sesskey, int len)
if ((state = malloc(sizeof(*state))) == NULL)
err(1, "malloc");

des_set_key((void *)sesskey, state->k1);
des_set_key((void *)(sesskey + 8), state->k2);
DES_set_key((void *)sesskey, &state->k1);
DES_set_key((void *)(sesskey + 8), &state->k2);

if (len <= 16)
des_set_key((void *)sesskey, state->k3);
DES_set_key((void *)sesskey, &state->k3);
else
des_set_key((void *)(sesskey + 16), state->k3);
DES_set_key((void *)(sesskey + 16), &state->k3);

memset(state->iv1, 0, 8);
memset(state->iv2, 0, 8);
Expand All @@ -177,9 +185,9 @@ des3_encrypt(u_char *src, u_char *dst, int len, void *state)
estate = (struct des3_state *)state;
memcpy(estate->iv1, estate->iv2, 8);

des_ncbc_encrypt(src, dst, len, estate->k1, &estate->iv1, DES_ENCRYPT);
des_ncbc_encrypt(dst, dst, len, estate->k2, &estate->iv2, DES_DECRYPT);
des_ncbc_encrypt(dst, dst, len, estate->k3, &estate->iv3, DES_ENCRYPT);
DES_ncbc_encrypt(src, dst, len, &estate->k1, &estate->iv1, DES_ENCRYPT);
DES_ncbc_encrypt(dst, dst, len, &estate->k2, &estate->iv2, DES_DECRYPT);
DES_ncbc_encrypt(dst, dst, len, &estate->k3, &estate->iv3, DES_ENCRYPT);
}

void
Expand All @@ -190,7 +198,7 @@ des3_decrypt(u_char *src, u_char *dst, int len, void *state)
dstate = (struct des3_state *)state;
memcpy(dstate->iv1, dstate->iv2, 8);

des_ncbc_encrypt(src, dst, len, dstate->k3, &dstate->iv3, DES_DECRYPT);
des_ncbc_encrypt(dst, dst, len, dstate->k2, &dstate->iv2, DES_ENCRYPT);
des_ncbc_encrypt(dst, dst, len, dstate->k1, &dstate->iv1, DES_DECRYPT);
DES_ncbc_encrypt(src, dst, len, &dstate->k3, &dstate->iv3, DES_DECRYPT);
DES_ncbc_encrypt(dst, dst, len, &dstate->k2, &dstate->iv2, DES_ENCRYPT);
DES_ncbc_encrypt(dst, dst, len, &dstate->k1, &dstate->iv1, DES_DECRYPT);
}