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Untangle iSCSI authentication code by splitting off the CHAP

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implementation.

Reviewed by:	mav@
MFC after:	1 month
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Edward Tomasz Napierala 2014-10-22 08:59:23 +00:00
parent 58a3dcb229
commit 45078155e3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=273459
8 changed files with 893 additions and 393 deletions
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2
usr.sbin/ctld/Makefile
View File

@ -1,7 +1,7 @@
# $FreeBSD$
PROG= ctld
SRCS= ctld.c discovery.c kernel.c keys.c log.c login.c parse.y pdu.c token.l y.tab.h
SRCS= chap.c ctld.c discovery.c kernel.c keys.c log.c login.c parse.y pdu.c token.l y.tab.h
CFLAGS+= -I${.CURDIR}
CFLAGS+= -I${.CURDIR}/../../sys
CFLAGS+= -I${.CURDIR}/../../sys/cam/ctl

386
usr.sbin/ctld/chap.c Normal file
View File

@ -0,0 +1,386 @@
/*-
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <assert.h>
#include <string.h>
#include <openssl/err.h>
#include <openssl/md5.h>
#include <openssl/rand.h>
#include "ctld.h"
static void
chap_compute_md5(const char id, const char *secret,
const void *challenge, size_t challenge_len, void *response,
size_t response_len)
{
MD5_CTX ctx;
int rv;
assert(response_len == MD5_DIGEST_LENGTH);
MD5_Init(&ctx);
MD5_Update(&ctx, &id, sizeof(id));
MD5_Update(&ctx, secret, strlen(secret));
MD5_Update(&ctx, challenge, challenge_len);
rv = MD5_Final(response, &ctx);
if (rv != 1)
log_errx(1, "MD5_Final");
}
static int
chap_hex2int(const char hex)
{
switch (hex) {
case '0':
return (0x00);
case '1':
return (0x01);
case '2':
return (0x02);
case '3':
return (0x03);
case '4':
return (0x04);
case '5':
return (0x05);
case '6':
return (0x06);
case '7':
return (0x07);
case '8':
return (0x08);
case '9':
return (0x09);
case 'a':
case 'A':
return (0x0a);
case 'b':
case 'B':
return (0x0b);
case 'c':
case 'C':
return (0x0c);
case 'd':
case 'D':
return (0x0d);
case 'e':
case 'E':
return (0x0e);
case 'f':
case 'F':
return (0x0f);
default:
return (-1);
}
}
/*
* XXX: Review this _carefully_.
*/
static int
chap_hex2bin(const char *hex, void **binp, size_t *bin_lenp)
{
int i, hex_len, nibble;
bool lo = true; /* As opposed to 'hi'. */
char *bin;
size_t bin_off, bin_len;
if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
log_warnx("malformed variable, should start with \"0x\"");
return (-1);
}
hex += strlen("0x");
hex_len = strlen(hex);
if (hex_len < 1) {
log_warnx("malformed variable; doesn't contain anything "
"but \"0x\"");
return (-1);
}
bin_len = hex_len / 2 + hex_len % 2;
bin = calloc(bin_len, 1);
if (bin == NULL)
log_err(1, "calloc");
bin_off = bin_len - 1;
for (i = hex_len - 1; i >= 0; i--) {
nibble = chap_hex2int(hex[i]);
if (nibble < 0) {
log_warnx("malformed variable, invalid char \"%c\"",
hex[i]);
free(bin);
return (-1);
}
assert(bin_off < bin_len);
if (lo) {
bin[bin_off] = nibble;
lo = false;
} else {
bin[bin_off] |= nibble << 4;
bin_off--;
lo = true;
}
}
*binp = bin;
*bin_lenp = bin_len;
return (0);
}
static char *
chap_bin2hex(const char *bin, size_t bin_len)
{
unsigned char *hex, *tmp, ch;
size_t hex_len;
size_t i;
hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
hex = malloc(hex_len);
if (hex == NULL)
log_err(1, "malloc");
tmp = hex;
tmp += sprintf(tmp, "0x");
for (i = 0; i < bin_len; i++) {
ch = bin[i];
tmp += sprintf(tmp, "%02x", ch);
}
return (hex);
}
struct chap *
chap_new(void)
{
struct chap *chap;
int rv;
chap = calloc(sizeof(*chap), 1);
if (chap == NULL)
log_err(1, "calloc");
/*
* Generate the challenge.
*/
rv = RAND_bytes(chap->chap_challenge, sizeof(chap->chap_challenge));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
rv = RAND_bytes(&chap->chap_id, sizeof(chap->chap_id));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
return (chap);
}
char *
chap_get_id(const struct chap *chap)
{
char *chap_i;
int ret;
ret = asprintf(&chap_i, "%d", chap->chap_id);
if (ret < 0)
log_err(1, "asprintf");
return (chap_i);
}
char *
chap_get_challenge(const struct chap *chap)
{
char *chap_c;
chap_c = chap_bin2hex(chap->chap_challenge,
sizeof(chap->chap_challenge));
return (chap_c);
}
static int
chap_receive_bin(struct chap *chap, void *response, size_t response_len)
{
if (response_len != sizeof(chap->chap_response)) {
log_debugx("got CHAP response with invalid length; "
"got %zd, should be %zd",
response_len, sizeof(chap->chap_response));
return (1);
}
memcpy(chap->chap_response, response, response_len);
return (0);
}
int
chap_receive(struct chap *chap, const char *response)
{
void *response_bin;
size_t response_bin_len;
int error;
error = chap_hex2bin(response, &response_bin, &response_bin_len);
if (error != 0) {
log_debugx("got incorrectly encoded CHAP response \"%s\"",
response);
return (1);
}
error = chap_receive_bin(chap, response_bin, response_bin_len);
free(response_bin);
return (error);
}
int
chap_authenticate(struct chap *chap, const char *secret)
{
char expected_response[MD5_DIGEST_LENGTH];
chap_compute_md5(chap->chap_id, secret,
chap->chap_challenge, sizeof(chap->chap_challenge),
expected_response, sizeof(expected_response));
if (memcmp(chap->chap_response,
expected_response, sizeof(expected_response)) != 0) {
return (-1);
}
return (0);
}
void
chap_delete(struct chap *chap)
{
free(chap);
}
struct rchap *
rchap_new(const char *secret)
{
struct rchap *rchap;
rchap = calloc(sizeof(*rchap), 1);
if (rchap == NULL)
log_err(1, "calloc");
rchap->rchap_secret = checked_strdup(secret);
return (rchap);
}
static void
rchap_receive_bin(struct rchap *rchap, const unsigned char id,
const void *challenge, size_t challenge_len)
{
rchap->rchap_id = id;
rchap->rchap_challenge = calloc(challenge_len, 1);
if (rchap->rchap_challenge == NULL)
log_err(1, "calloc");
memcpy(rchap->rchap_challenge, challenge, challenge_len);
rchap->rchap_challenge_len = challenge_len;
}
int
rchap_receive(struct rchap *rchap, const char *id, const char *challenge)
{
unsigned char id_bin;
void *challenge_bin;
size_t challenge_bin_len;
int error;
id_bin = strtoul(id, NULL, 10);
error = chap_hex2bin(challenge, &challenge_bin, &challenge_bin_len);
if (error != 0) {
log_debugx("got incorrectly encoded CHAP challenge \"%s\"",
challenge);
return (1);
}
rchap_receive_bin(rchap, id_bin, challenge_bin, challenge_bin_len);
free(challenge_bin);
return (0);
}
static void
rchap_get_response_bin(struct rchap *rchap,
void **responsep, size_t *response_lenp)
{
void *response_bin;
size_t response_bin_len = MD5_DIGEST_LENGTH;
response_bin = calloc(response_bin_len, 1);
if (response_bin == NULL)
log_err(1, "calloc");
chap_compute_md5(rchap->rchap_id, rchap->rchap_secret,
rchap->rchap_challenge, rchap->rchap_challenge_len,
response_bin, response_bin_len);
*responsep = response_bin;
*response_lenp = response_bin_len;
}
char *
rchap_get_response(struct rchap *rchap)
{
void *response;
size_t response_len;
char *chap_r;
rchap_get_response_bin(rchap, &response, &response_len);
chap_r = chap_bin2hex(response, response_len);
free(response);
return (chap_r);
}
void
rchap_delete(struct rchap *rchap)
{
free(rchap->rchap_secret);
free(rchap->rchap_challenge);
free(rchap);
}

30
usr.sbin/ctld/ctld.h
View File

@ -39,6 +39,7 @@
#include <sys/socket.h>
#include <stdbool.h>
#include <libutil.h>
#include <openssl/md5.h>
#define DEFAULT_CONFIG_PATH "/etc/ctl.conf"
#define DEFAULT_PIDFILE "/var/run/ctld.pid"
@ -207,6 +208,35 @@ struct keys {
size_t keys_data_len;
};
#define CHAP_CHALLENGE_LEN 1024
struct chap {
unsigned char chap_id;
char chap_challenge[CHAP_CHALLENGE_LEN];
char chap_response[MD5_DIGEST_LENGTH];
};
struct rchap {
char *rchap_secret;
unsigned char rchap_id;
void *rchap_challenge;
size_t rchap_challenge_len;
};
struct chap *chap_new(void);
char *chap_get_id(const struct chap *chap);
char *chap_get_challenge(const struct chap *chap);
int chap_receive(struct chap *chap, const char *response);
int chap_authenticate(struct chap *chap,
const char *secret);
void chap_delete(struct chap *chap);
struct rchap *rchap_new(const char *secret);
int rchap_receive(struct rchap *rchap,
const char *id, const char *challenge);
char *rchap_get_response(struct rchap *rchap);
void rchap_delete(struct rchap *rchap);
struct conf *conf_new(void);
struct conf *conf_new_from_file(const char *path);
struct conf *conf_new_from_kernel(void);

226
usr.sbin/ctld/login.c
View File

@ -39,9 +39,6 @@ __FBSDID("$FreeBSD$");
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <openssl/err.h>
#include <openssl/md5.h>
#include <openssl/rand.h>
#include "ctld.h"
#include "iscsi_proto.h"
@ -229,150 +226,6 @@ login_list_prefers(const char *list,
return (-1);
}
static int
login_hex2int(const char hex)
{
switch (hex) {
case '0':
return (0x00);
case '1':
return (0x01);
case '2':
return (0x02);
case '3':
return (0x03);
case '4':
return (0x04);
case '5':
return (0x05);
case '6':
return (0x06);
case '7':
return (0x07);
case '8':
return (0x08);
case '9':
return (0x09);
case 'a':
case 'A':
return (0x0a);
case 'b':
case 'B':
return (0x0b);
case 'c':
case 'C':
return (0x0c);
case 'd':
case 'D':
return (0x0d);
case 'e':
case 'E':
return (0x0e);
case 'f':
case 'F':
return (0x0f);
default:
return (-1);
}
}
/*
* XXX: Review this _carefully_.
*/
static int
login_hex2bin(const char *hex, char **binp, size_t *bin_lenp)
{
int i, hex_len, nibble;
bool lo = true; /* As opposed to 'hi'. */
char *bin;
size_t bin_off, bin_len;
if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
log_warnx("malformed variable, should start with \"0x\"");
return (-1);
}
hex += strlen("0x");
hex_len = strlen(hex);
if (hex_len < 1) {
log_warnx("malformed variable; doesn't contain anything "
"but \"0x\"");
return (-1);
}
bin_len = hex_len / 2 + hex_len % 2;
bin = calloc(bin_len, 1);
if (bin == NULL)
log_err(1, "calloc");
bin_off = bin_len - 1;
for (i = hex_len - 1; i >= 0; i--) {
nibble = login_hex2int(hex[i]);
if (nibble < 0) {
log_warnx("malformed variable, invalid char \"%c\"",
hex[i]);
return (-1);
}
assert(bin_off < bin_len);
if (lo) {
bin[bin_off] = nibble;
lo = false;
} else {
bin[bin_off] |= nibble << 4;
bin_off--;
lo = true;
}
}
*binp = bin;
*bin_lenp = bin_len;
return (0);
}
static char *
login_bin2hex(const char *bin, size_t bin_len)
{
unsigned char *hex, *tmp, ch;
size_t hex_len;
size_t i;
hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
hex = malloc(hex_len);
if (hex == NULL)
log_err(1, "malloc");
tmp = hex;
tmp += sprintf(tmp, "0x");
for (i = 0; i < bin_len; i++) {
ch = bin[i];
tmp += sprintf(tmp, "%02x", ch);
}
return (hex);
}
static void
login_compute_md5(const char id, const char *secret,
const void *challenge, size_t challenge_len, void *response,
size_t response_len)
{
MD5_CTX ctx;
int rv;
assert(response_len == MD5_DIGEST_LENGTH);
MD5_Init(&ctx);
MD5_Update(&ctx, &id, sizeof(id));
MD5_Update(&ctx, secret, strlen(secret));
MD5_Update(&ctx, challenge, challenge_len);
rv = MD5_Final(response, &ctx);
if (rv != 1)
log_errx(1, "MD5_Final");
}
#define LOGIN_CHALLENGE_LEN 1024
static struct pdu *
login_receive_chap_a(struct connection *conn)
{
@ -400,21 +253,21 @@ login_receive_chap_a(struct connection *conn)
}
static void
login_send_chap_c(struct pdu *request, const unsigned char id,
const void *challenge, const size_t challenge_len)
login_send_chap_c(struct pdu *request, struct chap *chap)
{
struct pdu *response;
struct keys *response_keys;
char *chap_c, chap_i[4];
char *chap_c, *chap_i;
chap_c = login_bin2hex(challenge, challenge_len);
snprintf(chap_i, sizeof(chap_i), "%d", id);
chap_c = chap_get_challenge(chap);
chap_i = chap_get_id(chap);
response = login_new_response(request);
response_keys = keys_new();
keys_add(response_keys, "CHAP_A", "5");
keys_add(response_keys, "CHAP_I", chap_i);
keys_add(response_keys, "CHAP_C", chap_c);
free(chap_i);
free(chap_c);
keys_save(response_keys, response);
pdu_send(response);
@ -423,15 +276,12 @@ login_send_chap_c(struct pdu *request, const unsigned char id,
}
static struct pdu *
login_receive_chap_r(struct connection *conn,
struct auth_group *ag, const unsigned char id, const void *challenge,
const size_t challenge_len, const struct auth **cap)
login_receive_chap_r(struct connection *conn, struct auth_group *ag,
struct chap *chap, const struct auth **authp)
{
struct pdu *request;
struct keys *request_keys;
const char *chap_n, *chap_r;
char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH];
size_t response_bin_len;
const struct auth *auth;
int error;
@ -449,7 +299,7 @@ login_receive_chap_r(struct connection *conn,
login_send_error(request, 0x02, 0x07);
log_errx(1, "received CHAP Login PDU without CHAP_R");
}
error = login_hex2bin(chap_r, &response_bin, &response_bin_len);
error = chap_receive(chap, chap_r);
if (error != 0) {
login_send_error(request, 0x02, 0x07);
log_errx(1, "received CHAP Login PDU with malformed CHAP_R");
@ -469,21 +319,17 @@ login_receive_chap_r(struct connection *conn,
assert(auth->a_secret != NULL);
assert(strlen(auth->a_secret) > 0);
login_compute_md5(id, auth->a_secret, challenge,
challenge_len, expected_response_bin,
sizeof(expected_response_bin));
if (memcmp(response_bin, expected_response_bin,
sizeof(expected_response_bin)) != 0) {
error = chap_authenticate(chap, auth->a_secret);
if (error != 0) {
login_send_error(request, 0x02, 0x01);
log_errx(1, "CHAP authentication failed for user \"%s\"",
auth->a_user);
}
keys_delete(request_keys);
free(response_bin);
*cap = auth;
*authp = auth;
return (request);
}
@ -494,10 +340,9 @@ login_send_chap_success(struct pdu *request,
struct pdu *response;
struct keys *request_keys, *response_keys;
struct iscsi_bhs_login_response *bhslr2;
struct rchap *rchap;
const char *chap_i, *chap_c;
char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH];
size_t challenge_len;
unsigned char id;
char *chap_r;
int error;
response = login_new_response(request);
@ -530,21 +375,18 @@ login_send_chap_success(struct pdu *request,
"is not set", auth->a_user);
}
id = strtoul(chap_i, NULL, 10);
error = login_hex2bin(chap_c, &challenge, &challenge_len);
log_debugx("performing mutual authentication as user \"%s\"",
auth->a_mutual_user);
rchap = rchap_new(auth->a_mutual_secret);
error = rchap_receive(rchap, chap_i, chap_c);
if (error != 0) {
login_send_error(request, 0x02, 0x07);
log_errx(1, "received CHAP Login PDU with malformed "
"CHAP_C");
"CHAP_I or CHAP_C");
}
log_debugx("performing mutual authentication as user \"%s\"",
auth->a_mutual_user);
login_compute_md5(id, auth->a_mutual_secret, challenge,
challenge_len, response_bin, sizeof(response_bin));
chap_r = login_bin2hex(response_bin,
sizeof(response_bin));
chap_r = rchap_get_response(rchap);
rchap_delete(rchap);
response_keys = keys_new();
keys_add(response_keys, "CHAP_N", auth->a_mutual_user);
keys_add(response_keys, "CHAP_R", chap_r);
@ -564,10 +406,8 @@ static void
login_chap(struct connection *conn, struct auth_group *ag)
{
const struct auth *auth;
struct chap *chap;
struct pdu *request;
char challenge_bin[LOGIN_CHALLENGE_LEN];
unsigned char id;
int rv;
/*
* Receive CHAP_A PDU.
@ -578,34 +418,21 @@ login_chap(struct connection *conn, struct auth_group *ag)
/*
* Generate the challenge.
*/
rv = RAND_bytes(challenge_bin, sizeof(challenge_bin));
if (rv != 1) {
login_send_error(request, 0x03, 0x02);
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
rv = RAND_bytes(&id, sizeof(id));
if (rv != 1) {
login_send_error(request, 0x03, 0x02);
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
chap = chap_new();
/*
* Send the challenge.
*/
log_debugx("sending CHAP_C, binary challenge size is %zd bytes",
sizeof(challenge_bin));
login_send_chap_c(request, id, challenge_bin,
sizeof(challenge_bin));
sizeof(chap->chap_challenge));
login_send_chap_c(request, chap);
pdu_delete(request);
/*
* Receive CHAP_N/CHAP_R PDU and authenticate.
*/
log_debugx("waiting for CHAP_N/CHAP_R");
request = login_receive_chap_r(conn, ag, id, challenge_bin,
sizeof(challenge_bin), &auth);
request = login_receive_chap_r(conn, ag, chap, &auth);
/*
* Yay, authentication succeeded!
@ -614,6 +441,7 @@ login_chap(struct connection *conn, struct auth_group *ag)
"transitioning to Negotiation Phase", auth->a_user);
login_send_chap_success(request, auth);
pdu_delete(request);
chap_delete(chap);
}
static void

2
usr.sbin/iscsid/Makefile
View File

@ -1,7 +1,7 @@
# $FreeBSD$
PROG= iscsid
SRCS= discovery.c iscsid.c keys.c log.c login.c pdu.c
SRCS= chap.c discovery.c iscsid.c keys.c log.c login.c pdu.c
CFLAGS+= -I${.CURDIR}
CFLAGS+= -I${.CURDIR}/../../sys/cam
CFLAGS+= -I${.CURDIR}/../../sys/dev/iscsi

386
usr.sbin/iscsid/chap.c Normal file
View File

@ -0,0 +1,386 @@
/*-
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <assert.h>
#include <string.h>
#include <openssl/err.h>
#include <openssl/md5.h>
#include <openssl/rand.h>
#include "iscsid.h"
static void
chap_compute_md5(const char id, const char *secret,
const void *challenge, size_t challenge_len, void *response,
size_t response_len)
{
MD5_CTX ctx;
int rv;
assert(response_len == MD5_DIGEST_LENGTH);
MD5_Init(&ctx);
MD5_Update(&ctx, &id, sizeof(id));
MD5_Update(&ctx, secret, strlen(secret));
MD5_Update(&ctx, challenge, challenge_len);
rv = MD5_Final(response, &ctx);
if (rv != 1)
log_errx(1, "MD5_Final");
}
static int
chap_hex2int(const char hex)
{
switch (hex) {
case '0':
return (0x00);
case '1':
return (0x01);
case '2':
return (0x02);
case '3':
return (0x03);
case '4':
return (0x04);
case '5':
return (0x05);
case '6':
return (0x06);
case '7':
return (0x07);
case '8':
return (0x08);
case '9':
return (0x09);
case 'a':
case 'A':
return (0x0a);
case 'b':
case 'B':
return (0x0b);
case 'c':
case 'C':
return (0x0c);
case 'd':
case 'D':
return (0x0d);
case 'e':
case 'E':
return (0x0e);
case 'f':
case 'F':
return (0x0f);
default:
return (-1);
}
}
/*
* XXX: Review this _carefully_.
*/
static int
chap_hex2bin(const char *hex, void **binp, size_t *bin_lenp)
{
int i, hex_len, nibble;
bool lo = true; /* As opposed to 'hi'. */
char *bin;
size_t bin_off, bin_len;
if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
log_warnx("malformed variable, should start with \"0x\"");
return (-1);
}
hex += strlen("0x");
hex_len = strlen(hex);
if (hex_len < 1) {
log_warnx("malformed variable; doesn't contain anything "
"but \"0x\"");
return (-1);
}
bin_len = hex_len / 2 + hex_len % 2;
bin = calloc(bin_len, 1);
if (bin == NULL)
log_err(1, "calloc");
bin_off = bin_len - 1;
for (i = hex_len - 1; i >= 0; i--) {
nibble = chap_hex2int(hex[i]);
if (nibble < 0) {
log_warnx("malformed variable, invalid char \"%c\"",
hex[i]);
free(bin);
return (-1);
}
assert(bin_off < bin_len);
if (lo) {
bin[bin_off] = nibble;
lo = false;
} else {
bin[bin_off] |= nibble << 4;
bin_off--;
lo = true;
}
}
*binp = bin;
*bin_lenp = bin_len;
return (0);
}
static char *
chap_bin2hex(const char *bin, size_t bin_len)
{
unsigned char *hex, *tmp, ch;
size_t hex_len;
size_t i;
hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
hex = malloc(hex_len);
if (hex == NULL)
log_err(1, "malloc");
tmp = hex;
tmp += sprintf(tmp, "0x");
for (i = 0; i < bin_len; i++) {
ch = bin[i];
tmp += sprintf(tmp, "%02x", ch);
}
return (hex);
}
struct chap *
chap_new(void)
{
struct chap *chap;
int rv;
chap = calloc(sizeof(*chap), 1);
if (chap == NULL)
log_err(1, "calloc");
/*
* Generate the challenge.
*/
rv = RAND_bytes(chap->chap_challenge, sizeof(chap->chap_challenge));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
rv = RAND_bytes(&chap->chap_id, sizeof(chap->chap_id));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
return (chap);
}
char *
chap_get_id(const struct chap *chap)
{
char *chap_i;
int ret;
ret = asprintf(&chap_i, "%d", chap->chap_id);
if (ret < 0)
log_err(1, "asprintf");
return (chap_i);
}
char *
chap_get_challenge(const struct chap *chap)
{
char *chap_c;
chap_c = chap_bin2hex(chap->chap_challenge,
sizeof(chap->chap_challenge));
return (chap_c);
}
static int
chap_receive_bin(struct chap *chap, void *response, size_t response_len)
{
if (response_len != sizeof(chap->chap_response)) {
log_debugx("got CHAP response with invalid length; "
"got %zd, should be %zd",
response_len, sizeof(chap->chap_response));
return (1);
}
memcpy(chap->chap_response, response, response_len);
return (0);
}
int
chap_receive(struct chap *chap, const char *response)
{
void *response_bin;
size_t response_bin_len;
int error;
error = chap_hex2bin(response, &response_bin, &response_bin_len);
if (error != 0) {
log_debugx("got incorrectly encoded CHAP response \"%s\"",
response);
return (1);
}
error = chap_receive_bin(chap, response_bin, response_bin_len);
free(response_bin);
return (error);
}
int
chap_authenticate(struct chap *chap, const char *secret)
{
char expected_response[MD5_DIGEST_LENGTH];
chap_compute_md5(chap->chap_id, secret,
chap->chap_challenge, sizeof(chap->chap_challenge),
expected_response, sizeof(expected_response));
if (memcmp(chap->chap_response,
expected_response, sizeof(expected_response)) != 0) {
return (-1);
}
return (0);
}
void
chap_delete(struct chap *chap)
{
free(chap);
}
struct rchap *
rchap_new(const char *secret)
{
struct rchap *rchap;
rchap = calloc(sizeof(*rchap), 1);
if (rchap == NULL)
log_err(1, "calloc");
rchap->rchap_secret = checked_strdup(secret);
return (rchap);
}
static void
rchap_receive_bin(struct rchap *rchap, const unsigned char id,
const void *challenge, size_t challenge_len)
{
rchap->rchap_id = id;
rchap->rchap_challenge = calloc(challenge_len, 1);
if (rchap->rchap_challenge == NULL)
log_err(1, "calloc");
memcpy(rchap->rchap_challenge, challenge, challenge_len);
rchap->rchap_challenge_len = challenge_len;
}
int
rchap_receive(struct rchap *rchap, const char *id, const char *challenge)
{
unsigned char id_bin;
void *challenge_bin;
size_t challenge_bin_len;
int error;
id_bin = strtoul(id, NULL, 10);
error = chap_hex2bin(challenge, &challenge_bin, &challenge_bin_len);
if (error != 0) {
log_debugx("got incorrectly encoded CHAP challenge \"%s\"",
challenge);
return (1);
}
rchap_receive_bin(rchap, id_bin, challenge_bin, challenge_bin_len);
free(challenge_bin);
return (0);
}
static void
rchap_get_response_bin(struct rchap *rchap,
void **responsep, size_t *response_lenp)
{
void *response_bin;
size_t response_bin_len = MD5_DIGEST_LENGTH;
response_bin = calloc(response_bin_len, 1);
if (response_bin == NULL)
log_err(1, "calloc");
chap_compute_md5(rchap->rchap_id, rchap->rchap_secret,
rchap->rchap_challenge, rchap->rchap_challenge_len,
response_bin, response_bin_len);
*responsep = response_bin;
*response_lenp = response_bin_len;
}
char *
rchap_get_response(struct rchap *rchap)
{
void *response;
size_t response_len;
char *chap_r;
rchap_get_response_bin(rchap, &response, &response_len);
chap_r = chap_bin2hex(response, response_len);
free(response);
return (chap_r);
}
void
rchap_delete(struct rchap *rchap)
{
free(rchap->rchap_secret);
free(rchap->rchap_challenge);
free(rchap);
}

33
usr.sbin/iscsid/iscsid.h
View File

@ -34,6 +34,7 @@
#include <stdbool.h>
#include <stdint.h>
#include <openssl/md5.h>
#include <iscsi_ioctl.h>
@ -60,8 +61,7 @@ struct connection {
size_t conn_max_data_segment_length;
size_t conn_max_burst_length;
size_t conn_first_burst_length;
char conn_mutual_challenge[CONN_MUTUAL_CHALLENGE_LEN];
unsigned char conn_mutual_id;
struct chap *conn_mutual_chap;
};
struct pdu {
@ -80,6 +80,35 @@ struct keys {
size_t keys_data_len;
};
#define CHAP_CHALLENGE_LEN 1024
struct chap {
unsigned char chap_id;
char chap_challenge[CHAP_CHALLENGE_LEN];
char chap_response[MD5_DIGEST_LENGTH];
};
struct rchap {
char *rchap_secret;
unsigned char rchap_id;
void *rchap_challenge;
size_t rchap_challenge_len;
};
struct chap *chap_new(void);
char *chap_get_id(const struct chap *chap);
char *chap_get_challenge(const struct chap *chap);
int chap_receive(struct chap *chap, const char *response);
int chap_authenticate(struct chap *chap,
const char *secret);
void chap_delete(struct chap *chap);
struct rchap *rchap_new(const char *secret);
int rchap_receive(struct rchap *rchap,
const char *id, const char *challenge);
char *rchap_get_response(struct rchap *rchap);
void rchap_delete(struct rchap *rchap);
struct keys *keys_new(void);
void keys_delete(struct keys *key);
void keys_load(struct keys *keys, const struct pdu *pdu);

221
usr.sbin/iscsid/login.c
View File

@ -39,9 +39,6 @@ __FBSDID("$FreeBSD$");
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <openssl/err.h>
#include <openssl/md5.h>
#include <openssl/rand.h>
#include "iscsid.h"
#include "iscsi_proto.h"
@ -329,148 +326,6 @@ login_list_prefers(const char *list,
return (-1);
}
static int
login_hex2int(const char hex)
{
switch (hex) {
case '0':
return (0x00);
case '1':
return (0x01);
case '2':
return (0x02);
case '3':
return (0x03);
case '4':
return (0x04);
case '5':
return (0x05);
case '6':
return (0x06);
case '7':
return (0x07);
case '8':
return (0x08);
case '9':
return (0x09);
case 'a':
case 'A':
return (0x0a);
case 'b':
case 'B':
return (0x0b);
case 'c':
case 'C':
return (0x0c);
case 'd':
case 'D':
return (0x0d);
case 'e':
case 'E':
return (0x0e);
case 'f':
case 'F':
return (0x0f);
default:
return (-1);
}
}
/*
* XXX: Review this _carefully_.
*/
static int
login_hex2bin(const char *hex, char **binp, size_t *bin_lenp)
{
int i, hex_len, nibble;
bool lo = true; /* As opposed to 'hi'. */
char *bin;
size_t bin_off, bin_len;
if (strncasecmp(hex, "0x", strlen("0x")) != 0) {
log_warnx("malformed variable, should start with \"0x\"");
return (-1);
}
hex += strlen("0x");
hex_len = strlen(hex);
if (hex_len < 1) {
log_warnx("malformed variable; doesn't contain anything "
"but \"0x\"");
return (-1);
}
bin_len = hex_len / 2 + hex_len % 2;
bin = calloc(bin_len, 1);
if (bin == NULL)
log_err(1, "calloc");
bin_off = bin_len - 1;
for (i = hex_len - 1; i >= 0; i--) {
nibble = login_hex2int(hex[i]);
if (nibble < 0) {
log_warnx("malformed variable, invalid char \"%c\"",
hex[i]);
return (-1);
}
assert(bin_off < bin_len);
if (lo) {
bin[bin_off] = nibble;
lo = false;
} else {
bin[bin_off] |= nibble << 4;
bin_off--;
lo = true;
}
}
*binp = bin;
*bin_lenp = bin_len;
return (0);
}
static char *
login_bin2hex(const char *bin, size_t bin_len)
{
unsigned char *hex, *tmp, ch;
size_t hex_len;
size_t i;
hex_len = bin_len * 2 + 3; /* +2 for "0x", +1 for '\0'. */
hex = malloc(hex_len);
if (hex == NULL)
log_err(1, "malloc");
tmp = hex;
tmp += sprintf(tmp, "0x");
for (i = 0; i < bin_len; i++) {
ch = bin[i];
tmp += sprintf(tmp, "%02x", ch);
}
return (hex);
}
static void
login_compute_md5(const char id, const char *secret,
const void *challenge, size_t challenge_len, void *response,
size_t response_len)
{
MD5_CTX ctx;
int rv;
assert(response_len == MD5_DIGEST_LENGTH);
MD5_Init(&ctx);
MD5_Update(&ctx, &id, sizeof(id));
MD5_Update(&ctx, secret, strlen(secret));
MD5_Update(&ctx, challenge, challenge_len);
rv = MD5_Final(response, &ctx);
if (rv != 1)
log_errx(1, "MD5_Final");
}
static void
login_negotiate_key(struct connection *conn, const char *name,
const char *value)
@ -687,12 +542,11 @@ login_send_chap_r(struct pdu *response)
struct connection *conn;
struct pdu *request;
struct keys *request_keys, *response_keys;
struct rchap *rchap;
const char *chap_a, *chap_c, *chap_i;
char *chap_r, *challenge, response_bin[MD5_DIGEST_LENGTH];
size_t challenge_len;
int error, rv;
unsigned char id;
char *mutual_chap_c, mutual_chap_i[4];
char *chap_r;
int error;
char *mutual_chap_c, *mutual_chap_i;
/*
* As in the rest of the initiator, 'request' means
@ -720,17 +574,19 @@ login_send_chap_r(struct pdu *response)
if (chap_i == NULL)
log_errx(1, "received CHAP packet without CHAP_I");
if (strcmp(chap_a, "5") != 0)
if (strcmp(chap_a, "5") != 0) {
log_errx(1, "received CHAP packet "
"with unsupported CHAP_A \"%s\"", chap_a);
id = strtoul(chap_i, NULL, 10);
error = login_hex2bin(chap_c, &challenge, &challenge_len);
if (error != 0)
log_errx(1, "received CHAP packet with malformed CHAP_C");
login_compute_md5(id, conn->conn_conf.isc_secret,
challenge, challenge_len, response_bin, sizeof(response_bin));
free(challenge);
chap_r = login_bin2hex(response_bin, sizeof(response_bin));
}
rchap = rchap_new(conn->conn_conf.isc_secret);
error = rchap_receive(rchap, chap_i, chap_c);
if (error != 0) {
log_errx(1, "received CHAP packet "
"with malformed CHAP_I or CHAP_C");
}
chap_r = rchap_get_response(rchap);
rchap_delete(rchap);
keys_delete(response_keys);
@ -747,26 +603,15 @@ login_send_chap_r(struct pdu *response)
if (conn->conn_conf.isc_mutual_user[0] != '\0') {
log_debugx("requesting mutual authentication; "
"binary challenge size is %zd bytes",
sizeof(conn->conn_mutual_challenge));
sizeof(conn->conn_mutual_chap->chap_challenge));
rv = RAND_bytes(conn->conn_mutual_challenge,
sizeof(conn->conn_mutual_challenge));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
rv = RAND_bytes(&conn->conn_mutual_id,
sizeof(conn->conn_mutual_id));
if (rv != 1) {
log_errx(1, "RAND_bytes failed: %s",
ERR_error_string(ERR_get_error(), NULL));
}
mutual_chap_c = login_bin2hex(conn->conn_mutual_challenge,
sizeof(conn->conn_mutual_challenge));
snprintf(mutual_chap_i, sizeof(mutual_chap_i),
"%d", conn->conn_mutual_id);
assert(conn->conn_mutual_chap == NULL);
conn->conn_mutual_chap = chap_new();
mutual_chap_i = chap_get_id(conn->conn_mutual_chap);
mutual_chap_c = chap_get_challenge(conn->conn_mutual_chap);
keys_add(request_keys, "CHAP_I", mutual_chap_i);
keys_add(request_keys, "CHAP_C", mutual_chap_c);
free(mutual_chap_i);
free(mutual_chap_c);
}
@ -782,8 +627,6 @@ login_verify_mutual(const struct pdu *response)
struct connection *conn;
struct keys *response_keys;
const char *chap_n, *chap_r;
char *response_bin, expected_response_bin[MD5_DIGEST_LENGTH];
size_t response_bin_len;
int error;
conn = response->pdu_connection;
@ -797,28 +640,26 @@ login_verify_mutual(const struct pdu *response)
chap_r = keys_find(response_keys, "CHAP_R");
if (chap_r == NULL)
log_errx(1, "received CHAP Response PDU without CHAP_R");
error = login_hex2bin(chap_r, &response_bin, &response_bin_len);
if (error != 0)
log_errx(1, "received CHAP Response PDU with malformed CHAP_R");
error = chap_receive(conn->conn_mutual_chap, chap_r);
if (error != 0)
log_errx(1, "received CHAP Response PDU with invalid CHAP_R");
if (strcmp(chap_n, conn->conn_conf.isc_mutual_user) != 0) {
fail(conn, "Mutual CHAP failed");
log_errx(1, "mutual CHAP authentication failed: wrong user");
}
login_compute_md5(conn->conn_mutual_id,
conn->conn_conf.isc_mutual_secret, conn->conn_mutual_challenge,
sizeof(conn->conn_mutual_challenge), expected_response_bin,
sizeof(expected_response_bin));
if (memcmp(response_bin, expected_response_bin,
sizeof(expected_response_bin)) != 0) {
error = chap_authenticate(conn->conn_mutual_chap,
conn->conn_conf.isc_mutual_secret);
if (error != 0) {
fail(conn, "Mutual CHAP failed");
log_errx(1, "mutual CHAP authentication failed: wrong secret");
}
keys_delete(response_keys);
free(response_bin);
keys_delete(response_keys);
chap_delete(conn->conn_mutual_chap);
conn->conn_mutual_chap = NULL;
log_debugx("mutual CHAP authentication succeeded");
}