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path: root/drivers/target/iscsi/iscsi_target_auth.c
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-rw-r--r--drivers/target/iscsi/iscsi_target_auth.c603
1 files changed, 603 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 000000000..c8a248bd1
--- /dev/null
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -0,0 +1,603 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*******************************************************************************
+ * 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>
+ *
+ ******************************************************************************/
+
+#include <crypto/hash.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <target/iscsi/iscsi_target_core.h>
+#include "iscsi_target_nego.h"
+#include "iscsi_target_auth.h"
+
+static char *chap_get_digest_name(const int digest_type)
+{
+ switch (digest_type) {
+ case CHAP_DIGEST_MD5:
+ return "md5";
+ case CHAP_DIGEST_SHA1:
+ return "sha1";
+ case CHAP_DIGEST_SHA256:
+ return "sha256";
+ case CHAP_DIGEST_SHA3_256:
+ return "sha3-256";
+ default:
+ return NULL;
+ }
+}
+
+static int chap_gen_challenge(
+ struct iscsit_conn *conn,
+ int caller,
+ char *c_str,
+ unsigned int *c_len)
+{
+ int ret;
+ unsigned char *challenge_asciihex;
+ struct iscsi_chap *chap = conn->auth_protocol;
+
+ challenge_asciihex = kzalloc(chap->challenge_len * 2 + 1, GFP_KERNEL);
+ if (!challenge_asciihex)
+ return -ENOMEM;
+
+ memset(chap->challenge, 0, MAX_CHAP_CHALLENGE_LEN);
+
+ ret = get_random_bytes_wait(chap->challenge, chap->challenge_len);
+ if (unlikely(ret))
+ goto out;
+
+ bin2hex(challenge_asciihex, chap->challenge,
+ chap->challenge_len);
+ /*
+ * 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);
+
+out:
+ kfree(challenge_asciihex);
+ return ret;
+}
+
+static int chap_test_algorithm(const char *name)
+{
+ struct crypto_shash *tfm;
+
+ tfm = crypto_alloc_shash(name, 0, 0);
+ if (IS_ERR(tfm))
+ return -1;
+
+ crypto_free_shash(tfm);
+ return 0;
+}
+
+static int chap_check_algorithm(const char *a_str)
+{
+ char *tmp, *orig, *token, *digest_name;
+ long digest_type;
+ int r = CHAP_DIGEST_UNKNOWN;
+
+ 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 (kstrtol(token, 10, &digest_type))
+ continue;
+
+ digest_name = chap_get_digest_name(digest_type);
+ if (!digest_name)
+ continue;
+
+ pr_debug("Selected %s Algorithm\n", digest_name);
+ if (chap_test_algorithm(digest_name) < 0) {
+ pr_err("failed to allocate %s algo\n", digest_name);
+ } else {
+ r = digest_type;
+ goto out;
+ }
+ }
+out:
+ kfree(orig);
+ return r;
+}
+
+static void chap_close(struct iscsit_conn *conn)
+{
+ kfree(conn->auth_protocol);
+ conn->auth_protocol = NULL;
+}
+
+static struct iscsi_chap *chap_server_open(
+ struct iscsit_conn *conn,
+ struct iscsi_node_auth *auth,
+ const char *a_str,
+ char *aic_str,
+ unsigned int *aic_len)
+{
+ int digest_type;
+ 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;
+ digest_type = chap_check_algorithm(a_str);
+ switch (digest_type) {
+ case CHAP_DIGEST_MD5:
+ chap->digest_size = MD5_SIGNATURE_SIZE;
+ break;
+ case CHAP_DIGEST_SHA1:
+ chap->digest_size = SHA1_SIGNATURE_SIZE;
+ break;
+ case CHAP_DIGEST_SHA256:
+ chap->digest_size = SHA256_SIGNATURE_SIZE;
+ break;
+ case CHAP_DIGEST_SHA3_256:
+ chap->digest_size = SHA3_256_SIGNATURE_SIZE;
+ break;
+ case CHAP_DIGEST_UNKNOWN:
+ default:
+ pr_err("Unsupported CHAP_A value\n");
+ chap_close(conn);
+ return NULL;
+ }
+
+ chap->digest_name = chap_get_digest_name(digest_type);
+
+ /* Tie the challenge length to the digest size */
+ chap->challenge_len = chap->digest_size;
+
+ pr_debug("[server] Got CHAP_A=%d\n", digest_type);
+ *aic_len = sprintf(aic_str, "CHAP_A=%d", digest_type);
+ *aic_len += 1;
+ pr_debug("[server] Sending CHAP_A=%d\n", digest_type);
+
+ /*
+ * 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.
+ */
+ if (chap_gen_challenge(conn, 1, aic_str, aic_len) < 0) {
+ chap_close(conn);
+ return NULL;
+ }
+
+ return chap;
+}
+
+static const char base64_lookup_table[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static int chap_base64_decode(u8 *dst, const char *src, size_t len)
+{
+ int i, bits = 0, ac = 0;
+ const char *p;
+ u8 *cp = dst;
+
+ for (i = 0; i < len; i++) {
+ if (src[i] == '=')
+ return cp - dst;
+
+ p = strchr(base64_lookup_table, src[i]);
+ if (p == NULL || src[i] == 0)
+ return -2;
+
+ ac <<= 6;
+ ac += (p - base64_lookup_table);
+ bits += 6;
+ if (bits >= 8) {
+ *cp++ = (ac >> (bits - 8)) & 0xff;
+ ac &= ~(BIT(16) - BIT(bits - 8));
+ bits -= 8;
+ }
+ }
+ if (ac)
+ return -1;
+
+ return cp - dst;
+}
+
+static int chap_server_compute_hash(
+ struct iscsit_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 type;
+ unsigned char identifier[10], *initiatorchg = NULL;
+ unsigned char *initiatorchg_binhex = NULL;
+ unsigned char *digest = NULL;
+ unsigned char *response = NULL;
+ unsigned char *client_digest = NULL;
+ unsigned char *server_digest = NULL;
+ 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_shash *tfm = NULL;
+ struct shash_desc *desc = NULL;
+ int auth_ret = -1, ret, initiatorchg_len;
+
+ digest = kzalloc(chap->digest_size, GFP_KERNEL);
+ if (!digest) {
+ pr_err("Unable to allocate the digest buffer\n");
+ goto out;
+ }
+
+ response = kzalloc(chap->digest_size * 2 + 2, GFP_KERNEL);
+ if (!response) {
+ pr_err("Unable to allocate the response buffer\n");
+ goto out;
+ }
+
+ client_digest = kzalloc(chap->digest_size, GFP_KERNEL);
+ if (!client_digest) {
+ pr_err("Unable to allocate the client_digest buffer\n");
+ goto out;
+ }
+
+ server_digest = kzalloc(chap->digest_size, GFP_KERNEL);
+ if (!server_digest) {
+ pr_err("Unable to allocate the server_digest buffer\n");
+ goto out;
+ }
+
+ memset(identifier, 0, 10);
+ memset(chap_n, 0, MAX_CHAP_N_SIZE);
+ memset(chap_r, 0, MAX_RESPONSE_LENGTH);
+
+ initiatorchg = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
+ if (!initiatorchg) {
+ pr_err("Unable to allocate challenge buffer\n");
+ goto out;
+ }
+
+ initiatorchg_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
+ if (!initiatorchg_binhex) {
+ pr_err("Unable to allocate initiatorchg_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;
+ }
+
+ switch (type) {
+ case HEX:
+ if (strlen(chap_r) != chap->digest_size * 2) {
+ pr_err("Malformed CHAP_R\n");
+ goto out;
+ }
+ if (hex2bin(client_digest, chap_r, chap->digest_size) < 0) {
+ pr_err("Malformed CHAP_R: invalid HEX\n");
+ goto out;
+ }
+ break;
+ case BASE64:
+ if (chap_base64_decode(client_digest, chap_r, strlen(chap_r)) !=
+ chap->digest_size) {
+ pr_err("Malformed CHAP_R: invalid BASE64\n");
+ goto out;
+ }
+ break;
+ default:
+ pr_err("Could not find CHAP_R\n");
+ goto out;
+ }
+
+ pr_debug("[server] Got CHAP_R=%s\n", chap_r);
+
+ tfm = crypto_alloc_shash(chap->digest_name, 0, 0);
+ if (IS_ERR(tfm)) {
+ tfm = NULL;
+ pr_err("Unable to allocate struct crypto_shash\n");
+ goto out;
+ }
+
+ desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(tfm), GFP_KERNEL);
+ if (!desc) {
+ pr_err("Unable to allocate struct shash_desc\n");
+ goto out;
+ }
+
+ desc->tfm = tfm;
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0) {
+ pr_err("crypto_shash_init() failed\n");
+ goto out;
+ }
+
+ ret = crypto_shash_update(desc, &chap->id, 1);
+ if (ret < 0) {
+ pr_err("crypto_shash_update() failed for id\n");
+ goto out;
+ }
+
+ ret = crypto_shash_update(desc, (char *)&auth->password,
+ strlen(auth->password));
+ if (ret < 0) {
+ pr_err("crypto_shash_update() failed for password\n");
+ goto out;
+ }
+
+ ret = crypto_shash_finup(desc, chap->challenge,
+ chap->challenge_len, server_digest);
+ if (ret < 0) {
+ pr_err("crypto_shash_finup() failed for challenge\n");
+ goto out;
+ }
+
+ bin2hex(response, server_digest, chap->digest_size);
+ pr_debug("[server] %s Server Digest: %s\n",
+ chap->digest_name, response);
+
+ if (memcmp(server_digest, client_digest, chap->digest_size) != 0) {
+ pr_debug("[server] %s Digests do not match!\n\n",
+ chap->digest_name);
+ goto out;
+ } else
+ pr_debug("[server] %s Digests match, CHAP connection"
+ " successful.\n\n", chap->digest_name);
+ /*
+ * One way authentication has succeeded, return now if mutual
+ * authentication is not enabled.
+ */
+ if (!auth->authenticate_target) {
+ auth_ret = 0;
+ goto out;
+ }
+ /*
+ * Get CHAP_I.
+ */
+ ret = extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type);
+ if (ret == -ENOENT) {
+ pr_debug("Could not find CHAP_I. Initiator uses One way authentication.\n");
+ auth_ret = 0;
+ goto out;
+ }
+ if (ret < 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,
+ initiatorchg, &type) < 0) {
+ pr_err("Could not find CHAP_C.\n");
+ goto out;
+ }
+
+ switch (type) {
+ case HEX:
+ initiatorchg_len = DIV_ROUND_UP(strlen(initiatorchg), 2);
+ if (!initiatorchg_len) {
+ pr_err("Unable to convert incoming challenge\n");
+ goto out;
+ }
+ if (initiatorchg_len > 1024) {
+ pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
+ goto out;
+ }
+
+ if (hex2bin(initiatorchg_binhex, initiatorchg,
+ initiatorchg_len) < 0) {
+ pr_err("Malformed CHAP_C: invalid HEX\n");
+ goto out;
+ }
+ break;
+ case BASE64:
+ initiatorchg_len = chap_base64_decode(initiatorchg_binhex,
+ initiatorchg,
+ strlen(initiatorchg));
+ if (initiatorchg_len < 0) {
+ pr_err("Malformed CHAP_C: invalid BASE64\n");
+ goto out;
+ }
+ if (!initiatorchg_len) {
+ pr_err("Unable to convert incoming challenge\n");
+ goto out;
+ }
+ if (initiatorchg_len > 1024) {
+ pr_err("CHAP_C exceeds maximum binary size of 1024 bytes\n");
+ goto out;
+ }
+ break;
+ default:
+ pr_err("Could not find CHAP_C.\n");
+ goto out;
+ }
+
+ pr_debug("[server] Got CHAP_C=%s\n", initiatorchg);
+ /*
+ * During mutual authentication, the CHAP_C generated by the
+ * initiator must not match the original CHAP_C generated by
+ * the target.
+ */
+ if (initiatorchg_len == chap->challenge_len &&
+ !memcmp(initiatorchg_binhex, chap->challenge,
+ initiatorchg_len)) {
+ pr_err("initiator CHAP_C matches target CHAP_C, failing"
+ " login attempt\n");
+ goto out;
+ }
+ /*
+ * Generate CHAP_N and CHAP_R for mutual authentication.
+ */
+ ret = crypto_shash_init(desc);
+ if (ret < 0) {
+ pr_err("crypto_shash_init() failed\n");
+ goto out;
+ }
+
+ /* To handle both endiannesses */
+ id_as_uchar = id;
+ ret = crypto_shash_update(desc, &id_as_uchar, 1);
+ if (ret < 0) {
+ pr_err("crypto_shash_update() failed for id\n");
+ goto out;
+ }
+
+ ret = crypto_shash_update(desc, auth->password_mutual,
+ strlen(auth->password_mutual));
+ if (ret < 0) {
+ pr_err("crypto_shash_update() failed for"
+ " password_mutual\n");
+ goto out;
+ }
+ /*
+ * Convert received challenge to binary hex.
+ */
+ ret = crypto_shash_finup(desc, initiatorchg_binhex, initiatorchg_len,
+ digest);
+ if (ret < 0) {
+ pr_err("crypto_shash_finup() failed for ma challenge\n");
+ goto out;
+ }
+
+ /*
+ * 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.
+ */
+ bin2hex(response, digest, chap->digest_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_sensitive(desc);
+ if (tfm)
+ crypto_free_shash(tfm);
+ kfree(initiatorchg);
+ kfree(initiatorchg_binhex);
+ kfree(digest);
+ kfree(response);
+ kfree(server_digest);
+ kfree(client_digest);
+ return auth_ret;
+}
+
+u32 chap_main_loop(
+ struct iscsit_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_server_compute_hash(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;
+}