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531 lines
12 KiB
531 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/******************************************************************************* |
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* This file houses the main functions for the iSCSI CHAP support |
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* |
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* (c) Copyright 2007-2013 Datera, Inc. |
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* |
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* Author: Nicholas A. Bellinger <[email protected]> |
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* |
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******************************************************************************/ |
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|
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#include <crypto/hash.h> |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/err.h> |
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#include <linux/random.h> |
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#include <linux/scatterlist.h> |
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#include <target/iscsi/iscsi_target_core.h> |
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#include "iscsi_target_nego.h" |
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#include "iscsi_target_auth.h" |
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|
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static char *chap_get_digest_name(const int digest_type) |
|
{ |
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switch (digest_type) { |
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case CHAP_DIGEST_MD5: |
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return "md5"; |
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case CHAP_DIGEST_SHA1: |
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return "sha1"; |
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case CHAP_DIGEST_SHA256: |
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return "sha256"; |
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case CHAP_DIGEST_SHA3_256: |
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return "sha3-256"; |
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default: |
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return NULL; |
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} |
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} |
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|
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static int chap_gen_challenge( |
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struct iscsi_conn *conn, |
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int caller, |
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char *c_str, |
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unsigned int *c_len) |
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{ |
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int ret; |
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unsigned char *challenge_asciihex; |
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struct iscsi_chap *chap = conn->auth_protocol; |
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|
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challenge_asciihex = kzalloc(chap->challenge_len * 2 + 1, GFP_KERNEL); |
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if (!challenge_asciihex) |
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return -ENOMEM; |
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|
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memset(chap->challenge, 0, MAX_CHAP_CHALLENGE_LEN); |
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|
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ret = get_random_bytes_wait(chap->challenge, chap->challenge_len); |
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if (unlikely(ret)) |
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goto out; |
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|
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bin2hex(challenge_asciihex, chap->challenge, |
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chap->challenge_len); |
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/* |
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* Set CHAP_C, and copy the generated challenge into c_str. |
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*/ |
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*c_len += sprintf(c_str + *c_len, "CHAP_C=0x%s", challenge_asciihex); |
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*c_len += 1; |
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|
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pr_debug("[%s] Sending CHAP_C=0x%s\n\n", (caller) ? "server" : "client", |
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challenge_asciihex); |
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|
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out: |
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kfree(challenge_asciihex); |
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return ret; |
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} |
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|
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static int chap_test_algorithm(const char *name) |
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{ |
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struct crypto_shash *tfm; |
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|
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tfm = crypto_alloc_shash(name, 0, 0); |
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if (IS_ERR(tfm)) |
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return -1; |
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|
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crypto_free_shash(tfm); |
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return 0; |
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} |
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|
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static int chap_check_algorithm(const char *a_str) |
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{ |
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char *tmp, *orig, *token, *digest_name; |
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long digest_type; |
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int r = CHAP_DIGEST_UNKNOWN; |
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|
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tmp = kstrdup(a_str, GFP_KERNEL); |
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if (!tmp) { |
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pr_err("Memory allocation failed for CHAP_A temporary buffer\n"); |
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return CHAP_DIGEST_UNKNOWN; |
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} |
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orig = tmp; |
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|
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token = strsep(&tmp, "="); |
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if (!token) |
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goto out; |
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|
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if (strcmp(token, "CHAP_A")) { |
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pr_err("Unable to locate CHAP_A key\n"); |
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goto out; |
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} |
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while (token) { |
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token = strsep(&tmp, ","); |
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if (!token) |
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goto out; |
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|
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if (kstrtol(token, 10, &digest_type)) |
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continue; |
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|
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digest_name = chap_get_digest_name(digest_type); |
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if (!digest_name) |
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continue; |
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|
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pr_debug("Selected %s Algorithm\n", digest_name); |
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if (chap_test_algorithm(digest_name) < 0) { |
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pr_err("failed to allocate %s algo\n", digest_name); |
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} else { |
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r = digest_type; |
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goto out; |
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} |
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} |
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out: |
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kfree(orig); |
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return r; |
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} |
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|
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static void chap_close(struct iscsi_conn *conn) |
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{ |
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kfree(conn->auth_protocol); |
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conn->auth_protocol = NULL; |
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} |
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|
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static struct iscsi_chap *chap_server_open( |
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struct iscsi_conn *conn, |
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struct iscsi_node_auth *auth, |
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const char *a_str, |
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char *aic_str, |
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unsigned int *aic_len) |
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{ |
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int digest_type; |
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struct iscsi_chap *chap; |
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|
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if (!(auth->naf_flags & NAF_USERID_SET) || |
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!(auth->naf_flags & NAF_PASSWORD_SET)) { |
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pr_err("CHAP user or password not set for" |
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" Initiator ACL\n"); |
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return NULL; |
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} |
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|
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conn->auth_protocol = kzalloc(sizeof(struct iscsi_chap), GFP_KERNEL); |
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if (!conn->auth_protocol) |
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return NULL; |
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|
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chap = conn->auth_protocol; |
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digest_type = chap_check_algorithm(a_str); |
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switch (digest_type) { |
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case CHAP_DIGEST_MD5: |
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chap->digest_size = MD5_SIGNATURE_SIZE; |
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break; |
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case CHAP_DIGEST_SHA1: |
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chap->digest_size = SHA1_SIGNATURE_SIZE; |
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break; |
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case CHAP_DIGEST_SHA256: |
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chap->digest_size = SHA256_SIGNATURE_SIZE; |
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break; |
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case CHAP_DIGEST_SHA3_256: |
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chap->digest_size = SHA3_256_SIGNATURE_SIZE; |
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break; |
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case CHAP_DIGEST_UNKNOWN: |
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default: |
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pr_err("Unsupported CHAP_A value\n"); |
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chap_close(conn); |
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return NULL; |
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} |
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|
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chap->digest_name = chap_get_digest_name(digest_type); |
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|
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/* Tie the challenge length to the digest size */ |
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chap->challenge_len = chap->digest_size; |
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|
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pr_debug("[server] Got CHAP_A=%d\n", digest_type); |
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*aic_len = sprintf(aic_str, "CHAP_A=%d", digest_type); |
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*aic_len += 1; |
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pr_debug("[server] Sending CHAP_A=%d\n", digest_type); |
|
|
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/* |
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* Set Identifier. |
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*/ |
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chap->id = conn->tpg->tpg_chap_id++; |
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*aic_len += sprintf(aic_str + *aic_len, "CHAP_I=%d", chap->id); |
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*aic_len += 1; |
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pr_debug("[server] Sending CHAP_I=%d\n", chap->id); |
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/* |
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* Generate Challenge. |
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*/ |
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if (chap_gen_challenge(conn, 1, aic_str, aic_len) < 0) { |
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chap_close(conn); |
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return NULL; |
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} |
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|
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return chap; |
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} |
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|
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static int chap_server_compute_hash( |
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struct iscsi_conn *conn, |
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struct iscsi_node_auth *auth, |
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char *nr_in_ptr, |
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char *nr_out_ptr, |
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unsigned int *nr_out_len) |
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{ |
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unsigned long id; |
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unsigned char id_as_uchar; |
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unsigned char type; |
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unsigned char identifier[10], *initiatorchg = NULL; |
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unsigned char *initiatorchg_binhex = NULL; |
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unsigned char *digest = NULL; |
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unsigned char *response = NULL; |
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unsigned char *client_digest = NULL; |
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unsigned char *server_digest = NULL; |
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unsigned char chap_n[MAX_CHAP_N_SIZE], chap_r[MAX_RESPONSE_LENGTH]; |
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size_t compare_len; |
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struct iscsi_chap *chap = conn->auth_protocol; |
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struct crypto_shash *tfm = NULL; |
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struct shash_desc *desc = NULL; |
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int auth_ret = -1, ret, initiatorchg_len; |
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|
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digest = kzalloc(chap->digest_size, GFP_KERNEL); |
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if (!digest) { |
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pr_err("Unable to allocate the digest buffer\n"); |
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goto out; |
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} |
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response = kzalloc(chap->digest_size * 2 + 2, GFP_KERNEL); |
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if (!response) { |
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pr_err("Unable to allocate the response buffer\n"); |
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goto out; |
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} |
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|
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client_digest = kzalloc(chap->digest_size, GFP_KERNEL); |
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if (!client_digest) { |
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pr_err("Unable to allocate the client_digest buffer\n"); |
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goto out; |
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} |
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server_digest = kzalloc(chap->digest_size, GFP_KERNEL); |
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if (!server_digest) { |
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pr_err("Unable to allocate the server_digest buffer\n"); |
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goto out; |
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} |
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|
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memset(identifier, 0, 10); |
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memset(chap_n, 0, MAX_CHAP_N_SIZE); |
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memset(chap_r, 0, MAX_RESPONSE_LENGTH); |
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|
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initiatorchg = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL); |
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if (!initiatorchg) { |
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pr_err("Unable to allocate challenge buffer\n"); |
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goto out; |
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} |
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|
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initiatorchg_binhex = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL); |
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if (!initiatorchg_binhex) { |
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pr_err("Unable to allocate initiatorchg_binhex buffer\n"); |
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goto out; |
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} |
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/* |
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* Extract CHAP_N. |
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*/ |
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if (extract_param(nr_in_ptr, "CHAP_N", MAX_CHAP_N_SIZE, chap_n, |
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&type) < 0) { |
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pr_err("Could not find CHAP_N.\n"); |
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goto out; |
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} |
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if (type == HEX) { |
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pr_err("Could not find CHAP_N.\n"); |
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goto out; |
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} |
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|
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/* Include the terminating NULL in the compare */ |
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compare_len = strlen(auth->userid) + 1; |
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if (strncmp(chap_n, auth->userid, compare_len) != 0) { |
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pr_err("CHAP_N values do not match!\n"); |
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goto out; |
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} |
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pr_debug("[server] Got CHAP_N=%s\n", chap_n); |
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/* |
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* Extract CHAP_R. |
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*/ |
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if (extract_param(nr_in_ptr, "CHAP_R", MAX_RESPONSE_LENGTH, chap_r, |
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&type) < 0) { |
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pr_err("Could not find CHAP_R.\n"); |
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goto out; |
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} |
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if (type != HEX) { |
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pr_err("Could not find CHAP_R.\n"); |
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goto out; |
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} |
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if (strlen(chap_r) != chap->digest_size * 2) { |
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pr_err("Malformed CHAP_R\n"); |
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goto out; |
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} |
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if (hex2bin(client_digest, chap_r, chap->digest_size) < 0) { |
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pr_err("Malformed CHAP_R\n"); |
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goto out; |
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} |
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|
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pr_debug("[server] Got CHAP_R=%s\n", chap_r); |
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|
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tfm = crypto_alloc_shash(chap->digest_name, 0, 0); |
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if (IS_ERR(tfm)) { |
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tfm = NULL; |
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pr_err("Unable to allocate struct crypto_shash\n"); |
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goto out; |
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} |
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|
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desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(tfm), GFP_KERNEL); |
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if (!desc) { |
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pr_err("Unable to allocate struct shash_desc\n"); |
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goto out; |
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} |
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|
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desc->tfm = tfm; |
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|
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ret = crypto_shash_init(desc); |
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if (ret < 0) { |
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pr_err("crypto_shash_init() failed\n"); |
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goto out; |
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} |
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|
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ret = crypto_shash_update(desc, &chap->id, 1); |
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if (ret < 0) { |
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pr_err("crypto_shash_update() failed for id\n"); |
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goto out; |
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} |
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|
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ret = crypto_shash_update(desc, (char *)&auth->password, |
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strlen(auth->password)); |
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if (ret < 0) { |
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pr_err("crypto_shash_update() failed for password\n"); |
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goto out; |
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} |
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|
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ret = crypto_shash_finup(desc, chap->challenge, |
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chap->challenge_len, server_digest); |
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if (ret < 0) { |
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pr_err("crypto_shash_finup() failed for challenge\n"); |
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goto out; |
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} |
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|
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bin2hex(response, server_digest, chap->digest_size); |
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pr_debug("[server] %s Server Digest: %s\n", |
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chap->digest_name, response); |
|
|
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if (memcmp(server_digest, client_digest, chap->digest_size) != 0) { |
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pr_debug("[server] %s Digests do not match!\n\n", |
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chap->digest_name); |
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goto out; |
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} else |
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pr_debug("[server] %s Digests match, CHAP connection" |
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" successful.\n\n", chap->digest_name); |
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/* |
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* One way authentication has succeeded, return now if mutual |
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* authentication is not enabled. |
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*/ |
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if (!auth->authenticate_target) { |
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auth_ret = 0; |
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goto out; |
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} |
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/* |
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* Get CHAP_I. |
|
*/ |
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if (extract_param(nr_in_ptr, "CHAP_I", 10, identifier, &type) < 0) { |
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pr_err("Could not find CHAP_I.\n"); |
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goto out; |
|
} |
|
|
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if (type == HEX) |
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ret = kstrtoul(&identifier[2], 0, &id); |
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else |
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ret = kstrtoul(identifier, 0, &id); |
|
|
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if (ret < 0) { |
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pr_err("kstrtoul() failed for CHAP identifier: %d\n", ret); |
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goto out; |
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} |
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if (id > 255) { |
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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); |
|
/* |
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* Get CHAP_C. |
|
*/ |
|
if (extract_param(nr_in_ptr, "CHAP_C", CHAP_CHALLENGE_STR_LEN, |
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initiatorchg, &type) < 0) { |
|
pr_err("Could not find CHAP_C.\n"); |
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goto out; |
|
} |
|
|
|
if (type != HEX) { |
|
pr_err("Could not find CHAP_C.\n"); |
|
goto out; |
|
} |
|
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\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 && |
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!memcmp(initiatorchg_binhex, chap->challenge, |
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initiatorchg_len)) { |
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pr_err("initiator CHAP_C matches target CHAP_C, failing" |
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" login attempt\n"); |
|
goto out; |
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} |
|
/* |
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* Generate CHAP_N and CHAP_R for mutual authentication. |
|
*/ |
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ret = crypto_shash_init(desc); |
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if (ret < 0) { |
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pr_err("crypto_shash_init() failed\n"); |
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goto out; |
|
} |
|
|
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/* 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; |
|
} |
|
|
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ret = crypto_shash_update(desc, auth->password_mutual, |
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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 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_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; |
|
}
|
|
|