diff options
Diffstat (limited to 'drivers/target/iscsi/iscsi_target_auth.c')
| -rw-r--r-- | drivers/target/iscsi/iscsi_target_auth.c | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c new file mode 100644 index 00000000..db0cf7c8 --- /dev/null +++ b/drivers/target/iscsi/iscsi_target_auth.c @@ -0,0 +1,468 @@ +/******************************************************************************* + * This file houses the main functions for the iSCSI CHAP support + * + * \u00a9 Copyright 2007-2011 RisingTide Systems LLC. + * + * Licensed to the Linux Foundation under the General Public License (GPL) version 2. + * + * 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 "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_set_random(char *data, int length) +{ + long r; + unsigned n; + + while (length > 0) { + get_random_bytes(&r, sizeof(long)); + r = r ^ (r >> 8); + r = r ^ (r >> 4); + n = r & 0x7; + + get_random_bytes(&r, sizeof(long)); + r = r ^ (r >> 8); + r = r ^ (r >> 5); + n = (n << 3) | (r & 0x7); + + get_random_bytes(&r, sizeof(long)); + r = r ^ (r >> 8); + r = r ^ (r >> 5); + n = (n << 2) | (r & 0x3); + + *data++ = n; + length--; + } +} + +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); + + chap_set_random(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 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) +{ + 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; + /* + * We only support MD5 MDA presently. + */ + if (strncmp(a_str, "CHAP_A=5", 8)) { + pr_err("CHAP_A is not MD5.\n"); + return NULL; + } + 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); + /* + * Set Identifier. + */ + chap->id = ISCSI_TPG_C(conn)->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) +{ + char *endptr; + unsigned long id; + 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]; + 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; + } + + if (memcmp(chap_n, auth->userid, strlen(auth->userid)) != 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) + id = simple_strtoul(&identifier[2], &endptr, 0); + else + id = simple_strtoul(identifier, &endptr, 0); + 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; + } + /* + * 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; + } + + sg_init_one(&sg, &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_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; +} |