iscsi-target: Fix CHAP_A parameter list handling
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>
diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index de77d9a..155f338 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -71,6 +71,40 @@
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 @@
char *aic_str,
unsigned int *aic_len)
{
+ int ret;
struct iscsi_chap *chap;
if (!(auth->naf_flags & NAF_USERID_SET) ||
@@ -93,21 +128,24 @@
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.
*/
diff --git a/drivers/target/iscsi/iscsi_target_auth.h b/drivers/target/iscsi/iscsi_target_auth.h
index 2f463c0..d22f7b96 100644
--- a/drivers/target/iscsi/iscsi_target_auth.h
+++ b/drivers/target/iscsi/iscsi_target_auth.h
@@ -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