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iscsi-target: Fix CHAP_A parameter list handling

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The target is failing to handle list of CHAP_A key-value pair form
initiator.The target is expecting CHAP_A=5 always. In other cases,
where initiator sends list (for example) CHAP_A=6,5 target is failing
the security negotiation. Which is incorrect.

This patch handles the case (RFC 3720 section 11.1.4).
where in the initiator may send list of CHAP_A values and target replies
with appropriate CHAP_A value in response

(Drop whitespaces + rename to chap_check_algorithm + save original
 pointer + add explicit check for CHAP_A key - nab)

Signed-off-by: Tejas Vaykole <tejas.vaykole@calsoftinc.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Tejas Vaykole 2014-05-30 11:13:47 +05:30 committed by Nicholas Bellinger
parent cee6029ecf
commit 3160723c49
2 changed files with 52 additions and 13 deletions
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64
drivers/target/iscsi/iscsi_target_auth.c
View File

@ -71,6 +71,40 @@ static void chap_gen_challenge(
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,
@ -79,6 +113,7 @@ static struct iscsi_chap *chap_server_open(
char *aic_str,
unsigned int *aic_len)
{
int ret;
struct iscsi_chap *chap;
if (!(auth->naf_flags & NAF_USERID_SET) ||
@ -93,21 +128,24 @@ static struct iscsi_chap *chap_server_open(
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");
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;
}
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.
*/

1
drivers/target/iscsi/iscsi_target_auth.h
View File

@ -1,6 +1,7 @@
#ifndef _ISCSI_CHAP_H_
#define _ISCSI_CHAP_H_
#define CHAP_DIGEST_UNKNOWN 0
#define CHAP_DIGEST_MD5 5
#define CHAP_DIGEST_SHA 6