Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Tue, 08 Jul 2014 20:01:50 +0100 | Subject | [PATCH 3.2 062/125] iscsi-target: Reject mutual authentication with reflected CHAP_C |
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3.2.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Nicholas Bellinger <nab@linux-iscsi.org>
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: Ben Hutchings <ben@decadent.org.uk> --- drivers/target/iscsi/iscsi_target_auth.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/drivers/target/iscsi/iscsi_target_auth.c +++ b/drivers/target/iscsi/iscsi_target_auth.c @@ -337,6 +337,16 @@ 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);
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