nvmet: Implement basic In-Band Authentication

Implement NVMe-oF In-Band authentication according to NVMe TPAR 8006.
This patch adds three additional configfs entries 'dhchap_key',
'dhchap_ctrl_key', and 'dhchap_hash' to the 'host' configfs directory.
The 'dhchap_key' and 'dhchap_ctrl_key' entries need to be in the ASCII
format as specified in NVMe Base Specification v2.0 section 8.13.5.8
'Secret representation'.
'dhchap_hash' defaults to 'hmac(sha256)', and can be written to to
switch to a different HMAC algorithm.

Signed-off-by: Hannes Reinecke <hare@suse.de>

drivers/nvme/host/auth.h

@@ -16,6 +16,7 @@ int nvme_auth_dhgroup_id(const char *dhgroup_name);
 
 const char *nvme_auth_hmac_name(int hmac_id);
 const char *nvme_auth_digest_name(int hmac_id);
+int nvme_auth_hmac_hash_len(int hmac_id);
 int nvme_auth_hmac_id(const char *hmac_name);
 
 unsigned char *nvme_auth_extract_secret(unsigned char *secret,

drivers/nvme/target/Kconfig

@@ -83,3 +83,14 @@ config NVME_TARGET_TCP
 	  devices over TCP.
 
 	  If unsure, say N.
+
+config NVME_TARGET_AUTH
+	bool "NVMe over Fabrics In-band Authentication support"
+	depends on NVME_TARGET
+	select CRYPTO_HMAC
+	select CRYPTO_SHA256
+	select CRYPTO_SHA512
+	help
+	  This enables support for NVMe over Fabrics In-band Authentication
+
+	  If unsure, say N.

drivers/nvme/target/Makefile

@@ -13,6 +13,7 @@ nvmet-y		+= core.o configfs.o admin-cmd.o fabrics-cmd.o \
 			discovery.o io-cmd-file.o io-cmd-bdev.o
 nvmet-$(CONFIG_NVME_TARGET_PASSTHRU)	+= passthru.o
 nvmet-$(CONFIG_BLK_DEV_ZONED)		+= zns.o
+nvmet-$(CONFIG_NVME_TARGET_AUTH)	+= fabrics-cmd-auth.o auth.o
 nvme-loop-y	+= loop.o
 nvmet-rdma-y	+= rdma.o
 nvmet-fc-y	+= fc.o

drivers/nvme/target/admin-cmd.c

@@ -1014,6 +1014,10 @@ u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
 
 	if (nvme_is_fabrics(cmd))
 		return nvmet_parse_fabrics_cmd(req);
+
+	if (unlikely(!nvmet_check_auth_status(req)))
+		return NVME_SC_AUTH_REQUIRED | NVME_SC_DNR;
+
 	if (nvmet_is_disc_subsys(nvmet_req_subsys(req)))
 		return nvmet_parse_discovery_cmd(req);