From: Nicholas Bellinger Date: Fri, 6 Jun 2014 01:08:57 +0000 (-0700) Subject: iscsi-target: Reject mutual authentication with reflected CHAP_C X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=1d2b60a5545942b1376cb48c1d55843d71e3a08f;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git iscsi-target: Reject mutual authentication with reflected CHAP_C 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 Cc: stable@vger.kernel.org # 3.1+ Signed-off-by: Nicholas Bellinger --- diff --git a/drivers/target/iscsi/iscsi_target_auth.c b/drivers/target/iscsi/iscsi_target_auth.c index 155f33848aa6..19b842c3e0b3 100644 --- a/drivers/target/iscsi/iscsi_target_auth.c +++ b/drivers/target/iscsi/iscsi_target_auth.c @@ -352,6 +352,16 @@ 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);