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authorNicholas Bellinger <nab@linux-iscsi.org>2014-06-05 18:08:57 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-26 15:10:27 -0400
commit7f53daea4dd53f43dd10ac24f752f74063abe4fa (patch)
parent95f3bb9bd690350d1ba58cb1541a26ce2db209e8 (diff)
iscsi-target: Reject mutual authentication with reflected CHAP_C
commit 1d2b60a5545942b1376cb48c1d55843d71e3a08f upstream. This patch adds an explicit check in chap_server_compute_md5() to ensure the CHAP_C value received from the initiator during mutual authentication does not match the original CHAP_C provided by the target. This is in line with RFC-3720, section 8.2.1: Originators MUST NOT reuse the CHAP challenge sent by the Responder for the other direction of a bidirectional authentication. Responders MUST check for this condition and close the iSCSI TCP connection if it occurs. Reported-by: Tejas Vaykole <tejas.vaykole@calsoftinc.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c
index b54f6ecf90d9..cbb04f37ec36 100644
--- a/drivers/target/iscsi/iscsi_target_auth.c
+++ b/drivers/target/iscsi/iscsi_target_auth.c
@@ -342,6 +342,16 @@ static int chap_server_compute_md5(
goto out;
+ * During mutual authentication, the CHAP_C generated by the
+ * initiator must not match the original CHAP_C generated by
+ * the target.
+ */
+ if (!memcmp(challenge_binhex, chap->challenge, CHAP_CHALLENGE_LENGTH)) {
+ pr_err("initiator CHAP_C matches target CHAP_C, failing"
+ " login attempt\n");
+ goto out;
+ }
+ /*
* Generate CHAP_N and CHAP_R for mutual authentication.
tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);