git: cdbc4a074bec - main - Further refine the ExpDataSN checks for SCSI Response PDUs.

The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=cdbc4a074bec094dc7f1dfde0773a9417d118ffa

commit cdbc4a074bec094dc7f1dfde0773a9417d118ffa
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2021-10-26 21:50:05 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2021-10-26 21:50:05 +0000

    Further refine the ExpDataSN checks for SCSI Response PDUs.
    
    According to 11.4.8 in RFC 7143, ExpDataSN MUST be 0 if the response
    code is not Command Completed, but we were requiring it to always be
    the count of DataIn PDUs regardless of the response code.
    
    In addition, at least one target (OCI Oracle iSCSI block device)
    returns an ExpDataSN of 0 when returning a valid completion with an
    error status (Check Condition) in response to a SCSI Inquiry.  As a
    workaround for this target, only warn without resetting the connection
    for a 0 ExpDataSN for responses with a non-zero error status.
    
    PR:             259152
    Reported by:    dch
    Reviewed by:    dch, mav, emaste
    Fixes:          4f0f5bf99591 iscsi: Validate DataSN values in Data-In PDUs in the initiator.
    Sponsored by:   Chelsio Communications
    Differential Revision:  https://reviews.freebsd.org/D32650
---
 sys/dev/iscsi/iscsi.c | 40 ++++++++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/sys/dev/iscsi/iscsi.c b/sys/dev/iscsi/iscsi.c
index eba365f7ad3e..9f49db2ad935 100644
--- a/sys/dev/iscsi/iscsi.c
+++ b/sys/dev/iscsi/iscsi.c
@@ -892,15 +892,39 @@ iscsi_pdu_handle_scsi_response(struct icl_pdu *response)
 	}
 
 	ccb = io->io_ccb;
-	if (ntohl(bhssr->bhssr_expdatasn) != io->io_datasn) {
-		ISCSI_SESSION_WARN(is,
-		    "ExpDataSN mismatch in SCSI Response (%u vs %u)",
-		    ntohl(bhssr->bhssr_expdatasn), io->io_datasn);
-		icl_pdu_free(response);
-		iscsi_session_reconnect(is);
-		ISCSI_SESSION_UNLOCK(is);
-		return;
+	if (bhssr->bhssr_response == BHSSR_RESPONSE_COMMAND_COMPLETED) {
+		if (ntohl(bhssr->bhssr_expdatasn) != io->io_datasn) {
+			ISCSI_SESSION_WARN(is,
+			    "ExpDataSN mismatch in SCSI Response (%u vs %u)",
+			    ntohl(bhssr->bhssr_expdatasn), io->io_datasn);
+
+			/*
+			 * XXX: Permit an ExpDataSN of zero for errors.
+			 *
+			 * This doesn't conform to RFC 7143, but some
+			 * targets seem to do this.
+			 */
+			if (bhssr->bhssr_status != 0 &&
+			    bhssr->bhssr_expdatasn == htonl(0))
+				goto skip_expdatasn;
+
+			icl_pdu_free(response);
+			iscsi_session_reconnect(is);
+			ISCSI_SESSION_UNLOCK(is);
+			return;
+		}
+	} else {
+		if (bhssr->bhssr_expdatasn != htonl(0)) {
+			ISCSI_SESSION_WARN(is,
+			    "ExpDataSN mismatch in SCSI Response (%u vs 0)",
+			    ntohl(bhssr->bhssr_expdatasn));
+			icl_pdu_free(response);
+			iscsi_session_reconnect(is);
+			ISCSI_SESSION_UNLOCK(is);
+			return;
+		}
 	}
+skip_expdatasn:
 
 	/*
 	 * With iSER, after getting good response we can be sure