--- /dev/null
+/*******************************************************************************
+ * This file houses the main functions for the iSCSI CHAP support
+ *
+ * (c) Copyright 2007-2013 Datera, Inc.
+ *
+ * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ ******************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <linux/scatterlist.h>
+
+#include <target/iscsi/iscsi_target_core.h>
+#include "iscsi_target_nego.h"
+#include "iscsi_target_auth.h"
+
+static int chap_string_to_hex(unsigned char *dst, unsigned char *src, int len)
+{
+ int j = DIV_ROUND_UP(len, 2), rc;
+
+ rc = hex2bin(dst, src, j);
+ if (rc < 0)
+ pr_debug("CHAP string contains non hex digit symbols\n");
+
+ dst[j] = '\0';
+ return j;
+}
+
+static void chap_binaryhex_to_asciihex(char *dst, char *src, int src_len)
+{
+ int i;
+
+ for (i = 0; i < src_len; i++) {
+ sprintf(&dst[i*2], "%02x", (int) src[i] & 0xff);
+ }
+}
+
+static void chap_gen_challenge(
+ struct iscsi_conn *conn,
+ int caller,
+ char *c_str,
+ unsigned int *c_len)
+{
+ unsigned char challenge_asciihex[CHAP_CHALLENGE_LENGTH * 2 + 1];
+ struct iscsi_chap *chap = conn->auth_protocol;
+
+ memset(challenge_asciihex, 0, CHAP_CHALLENGE_LENGTH * 2 + 1);
+
+ get_random_bytes(chap->challenge, CHAP_CHALLENGE_LENGTH);
+ chap_binaryhex_to_asciihex(challenge_asciihex, chap->challenge,
+ CHAP_CHALLENGE_LENGTH);
+ /*
+ * Set CHAP_C, and copy the generated challenge into c_str.
+ */
+ *c_len += sprintf(c_str + *c_len, "CHAP_C=0x%s", challenge_asciihex);
+ *c_len += 1;
+
+ pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client",
+ challenge_asciihex);
+}
+
+static int chap_check_algorithm(const char *a_str)
+{
+ char *tmp, *orig, *token;
+
+ tmp = kstrdup(a_str, GFP_KERNEL);
+ if (!tmp) {
+ pr_err("Memory allocation failed for CHAP_A temporary buffer\n");
+ return CHAP_DIGEST_UNKNOWN;
+ }
+ orig = tmp;
+
+ token = strsep(&tmp, "=");
+ if (!token)
+ goto out;
+
+ if (strcmp(token, "CHAP_A")) {
+ pr_err("Unable to locate CHAP_A key\n");
+ goto out;
+ }
+ while (token) {
+ token = strsep(&tmp, ",");
+ if (!token)
+ goto out;
+
+ if (!strncmp(token, "5", 1)) {
+ pr_debug("Selected MD5 Algorithm\n");
+ kfree(orig);
+ return CHAP_DIGEST_MD5;
+ }
+ }
+out:
+ kfree(orig);
+ return CHAP_DIGEST_UNKNOWN;
+}
+
+static struct iscsi_chap *chap_server_open(
+ struct iscsi_conn *conn,
+ struct iscsi_node_auth *auth,
+ const char *a_str,
+ char *aic_str,
+ unsigned int *aic_len)
+{
+ int ret;
+ struct iscsi_chap *chap;
+
+ if (!(auth->naf_flags & NAF_USERID_SET) ||
+ !(auth->naf_flags & NAF_PASSWORD_SET)) {
+ pr_err("CHAP user or password not set for"
+ " Initiator ACL\n");
+ return NULL;
+ }
+
+ conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL);
+ if (!conn->auth_protocol)
+ return NULL;
+
+ chap = conn->auth_protocol;
+ ret = chap_check_algorithm(a_str);
+ switch (ret) {
+ case CHAP_DIGEST_MD5:
+ pr_debug("[server] Got CHAP_A=5\n");
+ /*
+ * Send back CHAP_A set to MD5.
+ */
+ *aic_len = sprintf(aic_str, "CHAP_A=5");
+ *aic_len += 1;
+ chap->digest_type = CHAP_DIGEST_MD5;
+ pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
+ break;
+ case CHAP_DIGEST_UNKNOWN:
+ default:
+ pr_err("Unsupported CHAP_A value\n");
+ return NULL;
+ }
+
+ /*
+ * Set Identifier.
+ */
+ chap->id = conn->tpg->tpg_chap_id++;
+ *aic_len += sprintf(aic_str + *aic_len, "CHAP_I=%d", chap->id);
+ *aic_len += 1;
+ pr_debug("[server] Sending CHAP_I=%d\n", chap->id);
+ /*
+ * Generate Challenge.
+ */
+ chap_gen_challenge(conn, 1, aic_str, aic_len);
+
+ return chap;
+}
+
+static void chap_close(struct iscsi_conn *conn)
+{
+ kfree(conn->auth_protocol);
+ conn->auth_protocol = NULL;
+}
+
+static int chap_server_compute_md5(
+ struct iscsi_conn *conn,
+ struct iscsi_node_auth *auth,
+ char *nr_in_ptr,
+ char *nr_out_ptr,
+ unsigned int *nr_out_len)
+{
+ unsigned long id;
+ unsigned char id_as_uchar;
+ unsigned char digest[MD5_SIGNATURE_SIZE];
+ unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
+ unsigned char identifier[10], *challenge = NULL;
+ unsigned char *challenge_binhex = NULL;
+ unsigned char client_digest[MD5_SIGNATURE_SIZE];
+ unsigned char server_digest[MD5_SIGNATURE_SIZE];
+ unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH];
+ size_t compare_len;
+ struct iscsi_chap *chap = conn->auth_protocol;
+ struct crypto_hash *tfm;
+ struct hash_desc desc;
+ struct scatterlist sg;
+ int auth_ret = -1, ret, challenge_len;
+
+ memset(identifier, 0, 10);
+ memset(chap_n, 0, MAX_CHAP_N_SIZE);
+ memset(chap_r, 0, MAX_RESPONSE_LENGTH);
+ memset(digest, 0, MD5_SIGNATURE_SIZE);
+ memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
+ memset(client_digest, 0, MD5_SIGNATURE_SIZE);
+ memset(server_digest, 0, MD5_SIGNATURE_SIZE);
+
+ challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
+ if (!challenge) {
+ pr_err("Unable to allocate challenge buffer\n");
+ goto out;
+ }
+
+ challenge_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
+ if (!challenge_binhex) {
+ pr_err("Unable to allocate challenge_binhex buffer\n");
+ goto out;
+ }
+ /*
+ * Extract CHAP_N.
+ */
+ if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n,
+ &type) < 0) {
+ pr_err("Could not find CHAP_N.\n");
+ goto out;
+ }
+ if (type == HEX) {
+ pr_err("Could not find CHAP_N.\n");
+ goto out;
+ }
+
+ /* Include the terminating NULL in the compare */
+ compare_len = strlen(auth->userid) + 1;
+ if (strncmp(chap_n, auth->userid, compare_len) != 0) {
+ pr_err("CHAP_N values do not match!\n");
+ goto out;
+ }
+ pr_debug("[server] Got CHAP_N=%s\n", chap_n);
+ /*
+ * Extract CHAP_R.
+ */
+ if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r,
+ &type) < 0) {
+ pr_err("Could not find CHAP_R.\n");
+ goto out;
+ }
+ if (type != HEX) {
+ pr_err("Could not find CHAP_R.\n");
+ goto out;
+ }
+
+ pr_debug("[server] Got CHAP_R=%s\n", chap_r);
+ chap_string_to_hex(client_digest, chap_r, strlen(chap_r));
+
+ tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm)) {
+ pr_err("Unable to allocate struct crypto_hash\n");
+ goto out;
+ }
+ desc.tfm = tfm;
+ desc.flags = 0;
+
+ ret = crypto_hash_init(&desc);
+ if (ret < 0) {
+ pr_err("crypto_hash_init() failed\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ sg_init_one(&sg, &chap->id, 1);
+ ret = crypto_hash_update(&desc, &sg, 1);
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for id\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ sg_init_one(&sg, &auth->password, strlen(auth->password));
+ ret = crypto_hash_update(&desc, &sg, strlen(auth->password));
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for password\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ sg_init_one(&sg, chap->challenge, CHAP_CHALLENGE_LENGTH);
+ ret = crypto_hash_update(&desc, &sg, CHAP_CHALLENGE_LENGTH);
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for challenge\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ ret = crypto_hash_final(&desc, server_digest);
+ if (ret < 0) {
+ pr_err("crypto_hash_final() failed for server digest\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+ crypto_free_hash(tfm);
+
+ chap_binaryhex_to_asciihex(response, server_digest, MD5_SIGNATURE_SIZE);
+ pr_debug("[server] MD5 Server Digest: %s\n", response);
+
+ if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
+ pr_debug("[server] MD5 Digests do not match!\n\n");
+ goto out;
+ } else
+ pr_debug("[server] MD5 Digests match, CHAP connetication"
+ " successful.\n\n");
+ /*
+ * One way authentication has succeeded, return now if mutual
+ * authentication is not enabled.
+ */
+ if (!auth->authenticate_target) {
+ kfree(challenge);
+ kfree(challenge_binhex);
+ return 0;
+ }
+ /*
+ * Get CHAP_I.
+ */
+ if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) {
+ pr_err("Could not find CHAP_I.\n");
+ goto out;
+ }
+
+ if (type == HEX)
+ ret = kstrtoul(&identifier[2], 0, &id);
+ else
+ ret = kstrtoul(identifier, 0, &id);
+
+ if (ret < 0) {
+ pr_err("kstrtoul() failed for CHAP identifier: %d\n", ret);
+ goto out;
+ }
+ if (id > 255) {
+ pr_err("chap identifier: %lu greater than 255\n", id);
+ goto out;
+ }
+ /*
+ * RFC 1994 says Identifier is no more than octet (8 bits).
+ */
+ pr_debug("[server] Got CHAP_I=%lu\n", id);
+ /*
+ * Get CHAP_C.
+ */
+ if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN,
+ challenge, &type) < 0) {
+ pr_err("Could not find CHAP_C.\n");
+ goto out;
+ }
+
+ if (type != HEX) {
+ pr_err("Could not find CHAP_C.\n");
+ goto out;
+ }
+ pr_debug("[server] Got CHAP_C=%s\n", challenge);
+ challenge_len = chap_string_to_hex(challenge_binhex, challenge,
+ strlen(challenge));
+ if (!challenge_len) {
+ pr_err("Unable to convert incoming challenge\n");
+ goto out;
+ }
+ if (challenge_len > 1024) {
+ pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
+ goto out;
+ }
+ /*
+ * During mutual authentication, the CHAP_C generated by the
+ * initiator must not match the original CHAP_C generated by
+ * the target.
+ */
+ if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {
+ pr_err("initiator CHAP_C matches target CHAP_C, failing"
+ " login attempt\n");
+ goto out;
+ }
+ /*
+ * Generate CHAP_N and CHAP_R for mutual authentication.
+ */
+ tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm)) {
+ pr_err("Unable to allocate struct crypto_hash\n");
+ goto out;
+ }
+ desc.tfm = tfm;
+ desc.flags = 0;
+
+ ret = crypto_hash_init(&desc);
+ if (ret < 0) {
+ pr_err("crypto_hash_init() failed\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ /* To handle both endiannesses */
+ id_as_uchar = id;
+ sg_init_one(&sg, &id_as_uchar, 1);
+ ret = crypto_hash_update(&desc, &sg, 1);
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for id\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ sg_init_one(&sg, auth->password_mutual,
+ strlen(auth->password_mutual));
+ ret = crypto_hash_update(&desc, &sg, strlen(auth->password_mutual));
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for"
+ " password_mutual\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+ /*
+ * Convert received challenge to binary hex.
+ */
+ sg_init_one(&sg, challenge_binhex, challenge_len);
+ ret = crypto_hash_update(&desc, &sg, challenge_len);
+ if (ret < 0) {
+ pr_err("crypto_hash_update() failed for ma challenge\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+
+ ret = crypto_hash_final(&desc, digest);
+ if (ret < 0) {
+ pr_err("crypto_hash_final() failed for ma digest\n");
+ crypto_free_hash(tfm);
+ goto out;
+ }
+ crypto_free_hash(tfm);
+ /*
+ * Generate CHAP_N and CHAP_R.
+ */
+ *nr_out_len = sprintf(nr_out_ptr, "CHAP_N=%s", auth->userid_mutual);
+ *nr_out_len += 1;
+ pr_debug("[server] Sending CHAP_N=%s\n", auth->userid_mutual);
+ /*
+ * Convert response from binary hex to ascii hext.
+ */
+ chap_binaryhex_to_asciihex(response, digest, MD5_SIGNATURE_SIZE);
+ *nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
+ response);
+ *nr_out_len += 1;
+ pr_debug("[server] Sending CHAP_R=0x%s\n", response);
+ auth_ret = 0;
+out:
+ kfree(challenge);
+ kfree(challenge_binhex);
+ return auth_ret;
+}
+
+static int chap_got_response(
+ struct iscsi_conn *conn,
+ struct iscsi_node_auth *auth,
+ char *nr_in_ptr,
+ char *nr_out_ptr,
+ unsigned int *nr_out_len)
+{
+ struct iscsi_chap *chap = conn->auth_protocol;
+
+ switch (chap->digest_type) {
+ case CHAP_DIGEST_MD5:
+ if (chap_server_compute_md5(conn, auth, nr_in_ptr,
+ nr_out_ptr, nr_out_len) < 0)
+ return -1;
+ return 0;
+ default:
+ pr_err("Unknown CHAP digest type %d!\n",
+ chap->digest_type);
+ return -1;
+ }
+}
+
+u32 chap_main_loop(
+ struct iscsi_conn *conn,
+ struct iscsi_node_auth *auth,
+ char *in_text,
+ char *out_text,
+ int *in_len,
+ int *out_len)
+{
+ struct iscsi_chap *chap = conn->auth_protocol;
+
+ if (!chap) {
+ chap = chap_server_open(conn, auth, in_text, out_text, out_len);
+ if (!chap)
+ return 2;
+ chap->chap_state = CHAP_STAGE_SERVER_AIC;
+ return 0;
+ } else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
+ convert_null_to_semi(in_text, *in_len);
+ if (chap_got_response(conn, auth, in_text, out_text,
+ out_len) < 0) {
+ chap_close(conn);
+ return 2;
+ }
+ if (auth->authenticate_target)
+ chap->chap_state = CHAP_STAGE_SERVER_NR;
+ else
+ *out_len = 0;
+ chap_close(conn);
+ return 1;
+ }
+
+ return 2;
+}
Code Review / kvmfornfv.git / blobdiff