scsi: target: iscsi: CHAP: add support for SHA1, SHA256 and SHA3-256
This patch modifies the chap_server_compute_hash() function to make it agnostic to the choice of hash algorithm that is used. It also adds support to three new hash algorithms: SHA1, SHA256 and SHA3-256. The chap_got_response() function has been removed because the digest type validity is already checked by chap_server_open() Link: https://lore.kernel.org/r/20191028123822.5864-2-mlombard@redhat.com Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Tested-by: Chris Leech <cleech@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Maurizio Lombardi
Martin K. Petersen
parent
f6b8540f40
commit
a572d24af4
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@ -18,6 +18,22 @@
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#include "iscsi_target_nego.h"
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#include "iscsi_target_auth.h"
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static char *chap_get_digest_name(const int digest_type)
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{
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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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static int chap_gen_challenge(
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struct iscsi_conn *conn,
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int caller,
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@ -46,9 +62,23 @@ static int chap_gen_challenge(
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return 0;
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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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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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crypto_free_shash(tfm);
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return 0;
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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;
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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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tmp = kstrdup(a_str, GFP_KERNEL);
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if (!tmp) {
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@ -70,15 +100,24 @@ static int chap_check_algorithm(const char *a_str)
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if (!token)
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goto out;
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if (!strcmp(token, "5")) {
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pr_debug("Selected MD5 Algorithm\n");
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kfree(orig);
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return CHAP_DIGEST_MD5;
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if (kstrtol(token, 10, &digest_type))
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continue;
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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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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 CHAP_DIGEST_UNKNOWN;
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return r;
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}
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static void chap_close(struct iscsi_conn *conn)
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@ -94,7 +133,7 @@ static struct iscsi_chap *chap_server_open(
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char *aic_str,
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unsigned int *aic_len)
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{
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int ret;
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int digest_type;
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struct iscsi_chap *chap;
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if (!(auth->naf_flags & NAF_USERID_SET) ||
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@ -109,17 +148,19 @@ static struct iscsi_chap *chap_server_open(
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return NULL;
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chap = conn->auth_protocol;
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ret = chap_check_algorithm(a_str);
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switch (ret) {
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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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pr_debug("[server] Got CHAP_A=5\n");
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/*
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* Send back CHAP_A set to MD5.
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*/
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*aic_len = sprintf(aic_str, "CHAP_A=5");
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*aic_len += 1;
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chap->digest_type = CHAP_DIGEST_MD5;
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pr_debug("[server] Sending CHAP_A=%d\n", chap->digest_type);
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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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@ -128,6 +169,13 @@ static struct iscsi_chap *chap_server_open(
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return NULL;
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}
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chap->digest_name = chap_get_digest_name(digest_type);
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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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@ -146,7 +194,7 @@ static struct iscsi_chap *chap_server_open(
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return chap;
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}
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static int chap_server_compute_md5(
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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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@ -155,12 +203,13 @@ static int chap_server_compute_md5(
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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 digest[MD5_SIGNATURE_SIZE];
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unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
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unsigned char type;
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unsigned char identifier[10], *challenge = NULL;
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unsigned char *challenge_binhex = NULL;
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unsigned char client_digest[MD5_SIGNATURE_SIZE];
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unsigned char server_digest[MD5_SIGNATURE_SIZE];
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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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@ -168,13 +217,33 @@ static int chap_server_compute_md5(
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struct shash_desc *desc = NULL;
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int auth_ret = -1, ret, challenge_len;
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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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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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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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memset(digest, 0, MD5_SIGNATURE_SIZE);
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memset(response, 0, MD5_SIGNATURE_SIZE * 2 + 2);
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memset(client_digest, 0, MD5_SIGNATURE_SIZE);
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memset(server_digest, 0, MD5_SIGNATURE_SIZE);
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challenge = kzalloc(CHAP_CHALLENGE_STR_LEN, GFP_KERNEL);
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if (!challenge) {
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@ -219,18 +288,18 @@ static int chap_server_compute_md5(
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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) != MD5_SIGNATURE_SIZE * 2) {
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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, MD5_SIGNATURE_SIZE) < 0) {
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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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pr_debug("[server] Got CHAP_R=%s\n", chap_r);
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tfm = crypto_alloc_shash("md5", 0, 0);
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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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@ -271,15 +340,15 @@ static int chap_server_compute_md5(
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goto out;
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}
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bin2hex(response, server_digest, MD5_SIGNATURE_SIZE);
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pr_debug("[server] MD5 Server Digest: %s\n", response);
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bin2hex(response, server_digest, chap->digest_size);
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pr_debug("[server] %s Server Digest: %s\n", hash_name, response);
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if (memcmp(server_digest, client_digest, MD5_SIGNATURE_SIZE) != 0) {
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pr_debug("[server] MD5 Digests do not match!\n\n");
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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", hash_name);
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goto out;
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} else
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pr_debug("[server] MD5 Digests match, CHAP connection"
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" successful.\n\n");
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pr_debug("[server] %s Digests match, CHAP connection"
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" successful.\n\n", hash_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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@ -393,7 +462,7 @@ static int chap_server_compute_md5(
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/*
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* Convert response from binary hex to ascii hext.
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*/
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bin2hex(response, digest, MD5_SIGNATURE_SIZE);
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bin2hex(response, digest, chap->digest_size);
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*nr_out_len += sprintf(nr_out_ptr + *nr_out_len, "CHAP_R=0x%s",
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response);
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*nr_out_len += 1;
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@ -405,31 +474,13 @@ out:
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crypto_free_shash(tfm);
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kfree(challenge);
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kfree(challenge_binhex);
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kfree(digest);
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kfree(response);
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kfree(server_digest);
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kfree(client_digest);
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return auth_ret;
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}
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static int chap_got_response(
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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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struct iscsi_chap *chap = conn->auth_protocol;
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switch (chap->digest_type) {
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case CHAP_DIGEST_MD5:
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if (chap_server_compute_md5(conn, auth, nr_in_ptr,
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nr_out_ptr, nr_out_len) < 0)
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return -1;
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return 0;
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default:
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pr_err("Unknown CHAP digest type %d!\n",
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chap->digest_type);
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return -1;
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}
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}
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u32 chap_main_loop(
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struct iscsi_conn *conn,
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struct iscsi_node_auth *auth,
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@ -448,7 +499,7 @@ u32 chap_main_loop(
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return 0;
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} else if (chap->chap_state == CHAP_STAGE_SERVER_AIC) {
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convert_null_to_semi(in_text, *in_len);
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if (chap_got_response(conn, auth, in_text, out_text,
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if (chap_server_compute_hash(conn, auth, in_text, out_text,
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out_len) < 0) {
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chap_close(conn);
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return 2;
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@ -6,14 +6,19 @@
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#define CHAP_DIGEST_UNKNOWN 0
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#define CHAP_DIGEST_MD5 5
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#define CHAP_DIGEST_SHA 6
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#define CHAP_DIGEST_SHA1 6
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#define CHAP_DIGEST_SHA256 7
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#define CHAP_DIGEST_SHA3_256 8
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#define CHAP_CHALLENGE_LENGTH 16
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#define CHAP_CHALLENGE_STR_LEN 4096
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#define MAX_RESPONSE_LENGTH 64 /* sufficient for MD5 */
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#define MAX_RESPONSE_LENGTH 128 /* sufficient for SHA3 256 */
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#define MAX_CHAP_N_SIZE 512
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#define MD5_SIGNATURE_SIZE 16 /* 16 bytes in a MD5 message digest */
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#define SHA1_SIGNATURE_SIZE 20 /* 20 bytes in a SHA1 message digest */
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#define SHA256_SIGNATURE_SIZE 32 /* 32 bytes in a SHA256 message digest */
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#define SHA3_256_SIGNATURE_SIZE 32 /* 32 bytes in a SHA3 256 message digest */
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#define CHAP_STAGE_CLIENT_A 1
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#define CHAP_STAGE_SERVER_AIC 2
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@ -28,9 +33,11 @@ extern u32 chap_main_loop(struct iscsi_conn *, struct iscsi_node_auth *, char *,
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int *, int *);
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struct iscsi_chap {
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unsigned char digest_type;
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unsigned char id;
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unsigned char challenge[CHAP_CHALLENGE_LENGTH];
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unsigned int challenge_len;
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unsigned char *digest_name;
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unsigned int digest_size;
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unsigned int authenticate_target;
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unsigned int chap_state;
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} ____cacheline_aligned;
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