nvme: In-band authentication support

+ * Return: the length of the resulting base64url-encoded string in bytes.

+ * Decodes a string using base64url encoding, i.e. the "Base 64 Encoding"
+ * specified by RFC 4648, including the '='-padding.

Quoted 1 line · Hannes Reinecke

+ * Return: the length of the resulting base64url-encoded string in bytes.

base64, not base64url.

Quoted 2 lines

+ * Decodes a string using base64url encoding, i.e. the "Base 64 Encoding"
+ * specified by RFC 4648, including the '='-padding.

base64, not base64url.

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 changed to switch to a different HMAC algorithm.

Signed-off-by Hannes Reinecke <[email protected]>

---
  drivers/nvme/target/Kconfig            |  11 +
  drivers/nvme/target/Makefile           |   1 +
  drivers/nvme/target/admin-cmd.c        |   4 +
  drivers/nvme/target/auth.c             | 345 ++++++++++++++++++
  drivers/nvme/target/configfs.c         | 102 +++++-
  drivers/nvme/target/core.c             |   8 +
  drivers/nvme/target/fabrics-cmd-auth.c | 466 +++++++++++++++++++++++++
  drivers/nvme/target/fabrics-cmd.c      |  30 +-
  drivers/nvme/target/nvmet.h            |  67 ++++
  9 files changed, 1031 insertions(+), 3 deletions(-)

create mode 100644 drivers/nvme/target/auth.c create mode 100644 drivers/nvme/target/fabrics-cmd-auth.c

drivers/nvme/target/Kconfig +11 -0

index 973561c93888..70f3c385fc9f 100644
@@ -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 +1 -0

index 9837e580fa7e..c66820102493 100644
@@ -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 +4 -0

index aa6d84d8848e..868d65c869cd 100644
@@ -1008,6 +1008,10 @@ 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_req_subsys(req)->type == NVME_NQN_DISC)
  		return nvmet_parse_discovery_cmd(req);
 

drivers/nvme/target/auth.c new file +211 -0

new file mode 100644
index 000000000000..7247a7b97644
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe over Fabrics DH-HMAC-CHAP authentication.
+ * Copyright (c) 2020 Hannes Reinecke, SUSE Software Solutions.
+ * All rights reserved.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <crypto/hash.h>
+#include <linux/crc32.h>
+#include <linux/base64.h>
+#include <linux/ctype.h>
+#include <linux/random.h>
+#include <asm/unaligned.h>
+
+#include "nvmet.h"
+#include "../host/auth.h"
+
+int nvmet_auth_set_host_key(struct nvmet_host *host, const char *secret)
+{
+	if (sscanf(secret, "DHHC-1:%hhd:%*s", &host->dhchap_key_hash) != 1)
+		return -EINVAL;
+	if (host->dhchap_key_hash > 3) {
+		pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+			 host->dhchap_key_hash);
+		return -EINVAL;
+	}
+	if (host->dhchap_key_hash > 0) {
+		/* Validate selected hash algorithm */
+		const char *hmac = nvme_auth_hmac_name(host->dhchap_key_hash);
+
+		if (!crypto_has_shash(hmac, 0, 0)) {
+			pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+			host->dhchap_key_hash = -1;
+			return -ENOTSUPP;
+		}
+		/* Use this hash as default */
+		if (!host->dhchap_hash_id)
+			host->dhchap_hash_id = host->dhchap_key_hash;
+	}
+	host->dhchap_secret = kstrdup(secret, GFP_KERNEL);
+	if (!host->dhchap_secret)
+		return -ENOMEM;
+	/* Default to SHA256 */
+	if (!host->dhchap_hash_id)
+		host->dhchap_hash_id = NVME_AUTH_DHCHAP_SHA256;
+
+	pr_debug("Using hash %s\n",
+		 nvme_auth_hmac_name(host->dhchap_hash_id));
+	return 0;
+}
+
+int nvmet_auth_set_ctrl_key(struct nvmet_host *host, const char *secret)
+{
+	unsigned char dhchap_key_hash;
+
+	if (sscanf(secret, "DHHC-1:%hhd:%*s", &dhchap_key_hash) != 1)
+		return -EINVAL;
+	if (dhchap_key_hash > 3) {
+		pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+			 dhchap_key_hash);
+		return -EINVAL;
+	}
+	if (dhchap_key_hash > 0) {
+		/* Validate selected hash algorithm */
+		const char *hmac = nvme_auth_hmac_name(dhchap_key_hash);
+
+		if (!crypto_has_shash(hmac, 0, 0)) {
+			pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+			return -ENOTSUPP;
+		}
+	}
+	host->dhchap_ctrl_secret = kstrdup(secret, GFP_KERNEL);
+	return host->dhchap_ctrl_secret ? 0 : -ENOMEM;
+}
+
+int nvmet_setup_auth(struct nvmet_ctrl *ctrl)
+{
+	int ret = 0;
+	struct nvmet_host_link *p;
+	struct nvmet_host *host = NULL;
+	const char *hash_name;
+
+	down_read(&nvmet_config_sem);
+	if (ctrl->subsys->type == NVME_NQN_DISC)
+		goto out_unlock;
+
+	if (ctrl->subsys->allow_any_host)
+		goto out_unlock;
+
+	list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
+		pr_debug("check %s\n", nvmet_host_name(p->host));
+		if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
+			continue;
+		host = p->host;
+		break;
+	}
+	if (!host) {
+		pr_debug("host %s not found\n", ctrl->hostnqn);
+		ret = -EPERM;
+		goto out_unlock;
+	}
+	if (!host->dhchap_secret) {
+		pr_debug("No authentication provided\n");
+		goto out_unlock;
+	}
+
+	if (ctrl->shash_tfm) {
+		if (host->dhchap_hash_id == ctrl->shash_id) {
+			pr_debug("Re-use existing hash ID %d\n",
+				 ctrl->shash_id);
+			goto out_unlock;
+		}
+		crypto_free_shash(ctrl->shash_tfm);
+		ctrl->shash_tfm = NULL;
+	}
+
+	hash_name = nvme_auth_hmac_name(host->dhchap_hash_id);
+	if (!hash_name) {
+		pr_warn("Hash ID %d invalid\n", host->dhchap_hash_id);
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	ctrl->shash_tfm = crypto_alloc_shash(hash_name, 0,
+					     CRYPTO_ALG_ALLOCATES_MEMORY);
+	if (IS_ERR(ctrl->shash_tfm)) {
+		pr_err("failed to allocate shash %s\n", hash_name);
+		ret = PTR_ERR(ctrl->shash_tfm);
+		ctrl->shash_tfm = NULL;
+		goto out_unlock;
+	}
+	ctrl->shash_id = host->dhchap_hash_id;
+
+	/* Skip the 'DHHC-1:XX:' prefix */
+	ctrl->dhchap_key = nvme_auth_extract_secret(host->dhchap_secret + 10,
+						    &ctrl->dhchap_key_len);
+	if (IS_ERR(ctrl->dhchap_key)) {
+		ret = PTR_ERR(ctrl->dhchap_key);
+		pr_debug("failed to extract host key, error %d\n", ret);
+		ctrl->dhchap_key = NULL;
+		goto out_free_hash;
+	}
+	pr_debug("%s: using key %*ph\n", __func__,
+		 (int)ctrl->dhchap_key_len, ctrl->dhchap_key);
+
+	if (!host->dhchap_ctrl_secret)
+		goto out_unlock;
+
+	ctrl->dhchap_ctrl_key = nvme_auth_extract_secret(host->dhchap_ctrl_secret + 10,
+							 &ctrl->dhchap_ctrl_key_len);
+	if (IS_ERR(ctrl->dhchap_ctrl_key)) {
+		ret = PTR_ERR(ctrl->dhchap_ctrl_key);
+		pr_debug("failed to extract ctrl key, error %d\n", ret);
+		ctrl->dhchap_ctrl_key = NULL;
+	}
+
+out_free_hash:
+	if (ret) {
+		if (ctrl->dhchap_key) {
+			kfree_sensitive(ctrl->dhchap_key);
+			ctrl->dhchap_key = NULL;
+		}
+		crypto_free_shash(ctrl->shash_tfm);
+		ctrl->shash_tfm = NULL;
+		ctrl->shash_id = 0;
+	}
+out_unlock:
+	up_read(&nvmet_config_sem);
+
+	return ret;
+}
+
+void nvmet_auth_sq_free(struct nvmet_sq *sq)
+{
+	kfree(sq->dhchap_c1);
+	sq->dhchap_c1 = NULL;
+	kfree(sq->dhchap_c2);
+	sq->dhchap_c2 = NULL;
+	kfree(sq->dhchap_skey);
+	sq->dhchap_skey = NULL;
+}
+
+void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
+{
+	if (ctrl->shash_tfm) {
+		crypto_free_shash(ctrl->shash_tfm);
+		ctrl->shash_tfm = NULL;
+		ctrl->shash_id = 0;
+	}
+	if (ctrl->dhchap_key) {
+		kfree_sensitive(ctrl->dhchap_key);
+		ctrl->dhchap_key = NULL;
+	}
+	if (ctrl->dhchap_ctrl_key) {
+		kfree_sensitive(ctrl->dhchap_ctrl_key);
+		ctrl->dhchap_ctrl_key = NULL;
+	}
+}
+
+bool nvmet_check_auth_status(struct nvmet_req *req)
+{
+	if (req->sq->ctrl->shash_tfm &&
+	    !req->sq->authenticated)
+		return false;
+	return true;
+}
+
+int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,

Quoted 295 lines · Hannes Reinecke

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 changed to switch to a different HMAC algorithm.

Signed-off-by Hannes Reinecke <[email protected]>

---
  drivers/nvme/target/Kconfig            |  11 + drivers/nvme/target/Makefile           |   1 + drivers/nvme/target/admin-cmd.c        |   4 + drivers/nvme/target/auth.c             | 345 ++++++++++++++++++ drivers/nvme/target/configfs.c         | 102 +++++- drivers/nvme/target/core.c             |   8 + drivers/nvme/target/fabrics-cmd-auth.c | 466 +++++++++++++++++++++++++ drivers/nvme/target/fabrics-cmd.c      |  30 +- drivers/nvme/target/nvmet.h            |  67 ++++

  9 files changed, 1031 insertions(+), 3 deletions(-)

  create mode 100644 drivers/nvme/target/auth.c create mode 100644 drivers/nvme/target/fabrics-cmd-auth.c

drivers/nvme/target/Kconfig +0 -0

index 973561c93888..70f3c385fc9f 100644
@@ -83,3 +83,14 @@ config NVME_TARGET_TCP

        devices over TCP.
          If unsure, say N.

drivers/nvme/target/Kconfig +11 -0

+
+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 +0 -0

index 9837e580fa7e..c66820102493 100644
@@ -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 +4 -0

index aa6d84d8848e..868d65c869cd 100644
@@ -1008,6 +1008,10 @@ 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_req_subsys(req)->type == NVME_NQN_DISC)
           return nvmet_parse_discovery_cmd(req);

  diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c new file mode 100644
index 000000000000..7247a7b97644

drivers/nvme/target/auth.c new file +138 -0

@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe over Fabrics DH-HMAC-CHAP authentication.
+ * Copyright (c) 2020 Hannes Reinecke, SUSE Software Solutions.
+ * All rights reserved.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <crypto/hash.h>
+#include <linux/crc32.h>
+#include <linux/base64.h>
+#include <linux/ctype.h>
+#include <linux/random.h>
+#include <asm/unaligned.h>
+
+#include "nvmet.h"
+#include "../host/auth.h"
+
+int nvmet_auth_set_host_key(struct nvmet_host *host, const char *secret)
+{
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &host->dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (host->dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             host->dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (host->dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(host->dhchap_key_hash);
+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            host->dhchap_key_hash = -1;
+            return -ENOTSUPP;
+        }
+        /* Use this hash as default */
+        if (!host->dhchap_hash_id)
+            host->dhchap_hash_id = host->dhchap_key_hash;
+    }
+    host->dhchap_secret = kstrdup(secret, GFP_KERNEL);
+    if (!host->dhchap_secret)
+        return -ENOMEM;
+    /* Default to SHA256 */
+    if (!host->dhchap_hash_id)
+        host->dhchap_hash_id = NVME_AUTH_DHCHAP_SHA256;
+
+    pr_debug("Using hash %s\n",
+         nvme_auth_hmac_name(host->dhchap_hash_id));
+    return 0;
+}
+
+int nvmet_auth_set_ctrl_key(struct nvmet_host *host, const char *secret)
+{
+    unsigned char dhchap_key_hash;
+
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(dhchap_key_hash);
+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            return -ENOTSUPP;
+        }
+    }
+    host->dhchap_ctrl_secret = kstrdup(secret, GFP_KERNEL);
+    return host->dhchap_ctrl_secret ? 0 : -ENOMEM;
+}
+
+int nvmet_setup_auth(struct nvmet_ctrl *ctrl)
+{
+    int ret = 0;
+    struct nvmet_host_link *p;
+    struct nvmet_host *host = NULL;
+    const char *hash_name;
+
+    down_read(&nvmet_config_sem);
+    if (ctrl->subsys->type == NVME_NQN_DISC)
+        goto out_unlock;
+
+    if (ctrl->subsys->allow_any_host)
+        goto out_unlock;
+
+    list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
+        pr_debug("check %s\n", nvmet_host_name(p->host));
+        if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
+            continue;
+        host = p->host;
+        break;
+    }
+    if (!host) {
+        pr_debug("host %s not found\n", ctrl->hostnqn);
+        ret = -EPERM;
+        goto out_unlock;
+    }
+    if (!host->dhchap_secret) {
+        pr_debug("No authentication provided\n");
+        goto out_unlock;
+    }
+
+    if (ctrl->shash_tfm) {
+        if (host->dhchap_hash_id == ctrl->shash_id) {
+            pr_debug("Re-use existing hash ID %d\n",
+                 ctrl->shash_id);
+            goto out_unlock;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+    }
+
+    hash_name = nvme_auth_hmac_name(host->dhchap_hash_id);
+    if (!hash_name) {
+        pr_warn("Hash ID %d invalid\n", host->dhchap_hash_id);
+        ret = -EINVAL;
+        goto out_unlock;
+    }
+    ctrl->shash_tfm = crypto_alloc_shash(hash_name, 0,
+                         CRYPTO_ALG_ALLOCATES_MEMORY);
+    if (IS_ERR(ctrl->shash_tfm)) {
+        pr_err("failed to allocate shash %s\n", hash_name);
+        ret = PTR_ERR(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        goto out_unlock;
+    }
+    ctrl->shash_id = host->dhchap_hash_id;
+
+    /* Skip the 'DHHC-1:XX:' prefix */
+    ctrl->dhchap_key = nvme_auth_extract_secret(host->dhchap_secret +

10,
+                            &ctrl->dhchap_key_len);
+    if (IS_ERR(ctrl->dhchap_key)) {
+        ret = PTR_ERR(ctrl->dhchap_key);
+        pr_debug("failed to extract host key, error %d\n", ret); +        ctrl->dhchap_key = NULL;
+        goto out_free_hash;
+    }
+    pr_debug("%s: using key %*ph\n", __func__,
+         (int)ctrl->dhchap_key_len, ctrl->dhchap_key);

drivers/nvme/target/auth.c new file +5 -0

+
+    if (!host->dhchap_ctrl_secret)
+        goto out_unlock;
+
+    ctrl->dhchap_ctrl_key =

nvme_auth_extract_secret(host->dhchap_ctrl_secret + 10, +                             &ctrl->dhchap_ctrl_key_len); +    if (IS_ERR(ctrl->dhchap_ctrl_key)) {
+        ret = PTR_ERR(ctrl->dhchap_ctrl_key);
+        pr_debug("failed to extract ctrl key, error %d\n", ret); +        ctrl->dhchap_ctrl_key = NULL;
+    }

drivers/nvme/target/auth.c new file +60 -0

+
+out_free_hash:
+    if (ret) {
+        if (ctrl->dhchap_key) {
+            kfree_sensitive(ctrl->dhchap_key);
+            ctrl->dhchap_key = NULL;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+out_unlock:
+    up_read(&nvmet_config_sem);
+
+    return ret;
+}
+
+void nvmet_auth_sq_free(struct nvmet_sq *sq)
+{
+    kfree(sq->dhchap_c1);
+    sq->dhchap_c1 = NULL;
+    kfree(sq->dhchap_c2);
+    sq->dhchap_c2 = NULL;
+    kfree(sq->dhchap_skey);
+    sq->dhchap_skey = NULL;
+}
+
+void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
+{
+    if (ctrl->shash_tfm) {
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+    if (ctrl->dhchap_key) {
+        kfree_sensitive(ctrl->dhchap_key);
+        ctrl->dhchap_key = NULL;
+    }
+    if (ctrl->dhchap_ctrl_key) {
+        kfree_sensitive(ctrl->dhchap_ctrl_key);
+        ctrl->dhchap_ctrl_key = NULL;
+    }
+}
+
+bool nvmet_check_auth_status(struct nvmet_req *req)
+{
+    if (req->sq->ctrl->shash_tfm &&
+        !req->sq->authenticated)
+        return false;
+    return true;
+}
+
+int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
+             unsigned int shash_len)
+{
+    struct nvmet_ctrl *ctrl = req->sq->ctrl;
+    SHASH_DESC_ON_STACK(shash, ctrl->shash_tfm);
+    u8 *challenge = req->sq->dhchap_c1, *host_response;
+    u8 buf[4];
+    int ret;

Quoted 3 lines

+
+    if (shash_len != ctrl->dhchap_key_len)
+        return -EINVAL;

Is this condition correct? the shash_len is sent by the host and afaict the host is setting it by what the controller sent in the challenge. the ctrl->dhchap_key_len is taken from nvme_auth_extract_secret.

In other words, if the nvmet host is set to use hmac(sha512) then authentication fails, regardless of the key.

I think we need a set of blktests to sanity test different hash, dh_group, secrect-length, dhchap_key and dhchap_ctrl_key combinations.

The code is not trivial to follow with the different transformations, hashes etc...

Quoted 298 lines · Sagi Grimberg

Quoted 295 lines · Hannes Reinecke

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 changed to switch to a different HMAC algorithm.

Signed-off-by Hannes Reinecke <[email protected]>

---
   drivers/nvme/target/Kconfig            |  11 +
   drivers/nvme/target/Makefile           |   1 +
   drivers/nvme/target/admin-cmd.c        |   4 +
   drivers/nvme/target/auth.c             | 345 ++++++++++++++++++
   drivers/nvme/target/configfs.c         | 102 +++++-
   drivers/nvme/target/core.c             |   8 +
   drivers/nvme/target/fabrics-cmd-auth.c | 466 +++++++++++++++++++++++++
   drivers/nvme/target/fabrics-cmd.c      |  30 +-
   drivers/nvme/target/nvmet.h            |  67 ++++
   9 files changed, 1031 insertions(+), 3 deletions(-)

  create mode 100644 drivers/nvme/target/auth.c create mode 100644 drivers/nvme/target/fabrics-cmd-auth.c

drivers/nvme/target/Kconfig +11 -0

index 973561c93888..70f3c385fc9f 100644
@@ -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 +1 -0

index 9837e580fa7e..c66820102493 100644
@@ -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 +4 -0

index aa6d84d8848e..868d65c869cd 100644
@@ -1008,6 +1008,10 @@ 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_req_subsys(req)->type == NVME_NQN_DISC)
           return nvmet_parse_discovery_cmd(req);
   diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c

new file mode 100644
index 000000000000..7247a7b97644

drivers/nvme/target/auth.c new file +138 -0

@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe over Fabrics DH-HMAC-CHAP authentication.
+ * Copyright (c) 2020 Hannes Reinecke, SUSE Software Solutions.
+ * All rights reserved.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <crypto/hash.h>
+#include <linux/crc32.h>
+#include <linux/base64.h>
+#include <linux/ctype.h>
+#include <linux/random.h>
+#include <asm/unaligned.h>
+
+#include "nvmet.h"
+#include "../host/auth.h"
+
+int nvmet_auth_set_host_key(struct nvmet_host *host, const char *secret)
+{
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &host->dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (host->dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             host->dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (host->dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(host->dhchap_key_hash);
+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            host->dhchap_key_hash = -1;
+            return -ENOTSUPP;
+        }
+        /* Use this hash as default */
+        if (!host->dhchap_hash_id)
+            host->dhchap_hash_id = host->dhchap_key_hash;
+    }
+    host->dhchap_secret = kstrdup(secret, GFP_KERNEL);
+    if (!host->dhchap_secret)
+        return -ENOMEM;
+    /* Default to SHA256 */
+    if (!host->dhchap_hash_id)
+        host->dhchap_hash_id = NVME_AUTH_DHCHAP_SHA256;
+
+    pr_debug("Using hash %s\n",
+         nvme_auth_hmac_name(host->dhchap_hash_id));
+    return 0;
+}
+
+int nvmet_auth_set_ctrl_key(struct nvmet_host *host, const char *secret)
+{
+    unsigned char dhchap_key_hash;
+
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(dhchap_key_hash);
+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            return -ENOTSUPP;
+        }
+    }
+    host->dhchap_ctrl_secret = kstrdup(secret, GFP_KERNEL);
+    return host->dhchap_ctrl_secret ? 0 : -ENOMEM;
+}
+
+int nvmet_setup_auth(struct nvmet_ctrl *ctrl)
+{
+    int ret = 0;
+    struct nvmet_host_link *p;
+    struct nvmet_host *host = NULL;
+    const char *hash_name;
+
+    down_read(&nvmet_config_sem);
+    if (ctrl->subsys->type == NVME_NQN_DISC)
+        goto out_unlock;
+
+    if (ctrl->subsys->allow_any_host)
+        goto out_unlock;
+
+    list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
+        pr_debug("check %s\n", nvmet_host_name(p->host));
+        if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
+            continue;
+        host = p->host;
+        break;
+    }
+    if (!host) {
+        pr_debug("host %s not found\n", ctrl->hostnqn);
+        ret = -EPERM;
+        goto out_unlock;
+    }
+    if (!host->dhchap_secret) {
+        pr_debug("No authentication provided\n");
+        goto out_unlock;
+    }
+
+    if (ctrl->shash_tfm) {
+        if (host->dhchap_hash_id == ctrl->shash_id) {
+            pr_debug("Re-use existing hash ID %d\n",
+                 ctrl->shash_id);
+            goto out_unlock;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+    }
+
+    hash_name = nvme_auth_hmac_name(host->dhchap_hash_id);
+    if (!hash_name) {
+        pr_warn("Hash ID %d invalid\n", host->dhchap_hash_id);
+        ret = -EINVAL;
+        goto out_unlock;
+    }
+    ctrl->shash_tfm = crypto_alloc_shash(hash_name, 0,
+                         CRYPTO_ALG_ALLOCATES_MEMORY);
+    if (IS_ERR(ctrl->shash_tfm)) {
+        pr_err("failed to allocate shash %s\n", hash_name);
+        ret = PTR_ERR(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        goto out_unlock;
+    }
+    ctrl->shash_id = host->dhchap_hash_id;
+
+    /* Skip the 'DHHC-1:XX:' prefix */
+    ctrl->dhchap_key = nvme_auth_extract_secret(host->dhchap_secret +

10,
+                            &ctrl->dhchap_key_len);
+    if (IS_ERR(ctrl->dhchap_key)) {
+        ret = PTR_ERR(ctrl->dhchap_key);
+        pr_debug("failed to extract host key, error %d\n", ret); +        ctrl->dhchap_key = NULL;
+        goto out_free_hash;
+    }
+    pr_debug("%s: using key %*ph\n", __func__,
+         (int)ctrl->dhchap_key_len, ctrl->dhchap_key);

drivers/nvme/target/auth.c new file +5 -0

+
+    if (!host->dhchap_ctrl_secret)
+        goto out_unlock;
+
+    ctrl->dhchap_ctrl_key =

nvme_auth_extract_secret(host->dhchap_ctrl_secret + 10, +                             &ctrl->dhchap_ctrl_key_len); +    if (IS_ERR(ctrl->dhchap_ctrl_key)) {
+        ret = PTR_ERR(ctrl->dhchap_ctrl_key);
+        pr_debug("failed to extract ctrl key, error %d\n", ret); +        ctrl->dhchap_ctrl_key = NULL;
+    }

drivers/nvme/target/auth.c new file +60 -0

+
+out_free_hash:
+    if (ret) {
+        if (ctrl->dhchap_key) {
+            kfree_sensitive(ctrl->dhchap_key);
+            ctrl->dhchap_key = NULL;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+out_unlock:
+    up_read(&nvmet_config_sem);
+
+    return ret;
+}
+
+void nvmet_auth_sq_free(struct nvmet_sq *sq)
+{
+    kfree(sq->dhchap_c1);
+    sq->dhchap_c1 = NULL;
+    kfree(sq->dhchap_c2);
+    sq->dhchap_c2 = NULL;
+    kfree(sq->dhchap_skey);
+    sq->dhchap_skey = NULL;
+}
+
+void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
+{
+    if (ctrl->shash_tfm) {
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+    if (ctrl->dhchap_key) {
+        kfree_sensitive(ctrl->dhchap_key);
+        ctrl->dhchap_key = NULL;
+    }
+    if (ctrl->dhchap_ctrl_key) {
+        kfree_sensitive(ctrl->dhchap_ctrl_key);
+        ctrl->dhchap_ctrl_key = NULL;
+    }
+}
+
+bool nvmet_check_auth_status(struct nvmet_req *req)
+{
+    if (req->sq->ctrl->shash_tfm &&
+        !req->sq->authenticated)
+        return false;
+    return true;
+}
+
+int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
+             unsigned int shash_len)
+{
+    struct nvmet_ctrl *ctrl = req->sq->ctrl;
+    SHASH_DESC_ON_STACK(shash, ctrl->shash_tfm);
+    u8 *challenge = req->sq->dhchap_c1, *host_response;
+    u8 buf[4];
+    int ret;

Quoted 9 lines

Quoted 3 lines

+
+    if (shash_len != ctrl->dhchap_key_len)
+        return -EINVAL;

Is this condition correct? the shash_len is sent by the host and afaict the host is setting it by what the controller sent in the challenge. the ctrl->dhchap_key_len is taken from nvme_auth_extract_secret.

Ideally, but shash_len is actually sent by the host, so it _might_ be different (as it's picked up from the command sent by the host).

Quoted 3 lines

In other words, if the nvmet host is set to use hmac(sha512) then authentication fails, regardless of the key.

Nope. The hash algorithm is figured out the 'negotiation' step, so the host _should_ have set the correct hash length. But as this is networking you should be validating each field in the received packet to ensure it matches what you expect.

Quoted 320 lines · Hannes Reinecke

Quoted 307 lines · Sagi Grimberg

Quoted 304 lines · Hannes Reinecke

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 changed to switch to
a different HMAC algorithm.

Signed-off-by Hannes Reinecke <[email protected]>

---
   drivers/nvme/target/Kconfig            |  11 + drivers/nvme/target/Makefile           |   1 + drivers/nvme/target/admin-cmd.c        |   4 + drivers/nvme/target/auth.c             | 345 ++++++++++++++++++ drivers/nvme/target/configfs.c         | 102 +++++- drivers/nvme/target/core.c             |   8 + drivers/nvme/target/fabrics-cmd-auth.c | 466
+++++++++++++++++++++++++
   drivers/nvme/target/fabrics-cmd.c      |  30 +- drivers/nvme/target/nvmet.h            |  67 ++++

   9 files changed, 1031 insertions(+), 3 deletions(-)

   create mode 100644 drivers/nvme/target/auth.c create mode 100644 drivers/nvme/target/fabrics-cmd-auth.c

drivers/nvme/target/Kconfig +0 -0

index 973561c93888..70f3c385fc9f 100644
@@ -83,3 +83,14 @@ config NVME_TARGET_TCP

         devices over TCP.
           If unsure, say N.

drivers/nvme/target/Kconfig +9 -0

+
+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

drivers/nvme/target/Kconfig +2 -0

+
+      If unsure, say N.

drivers/nvme/target/Makefile +0 -0

index 9837e580fa7e..c66820102493 100644
@@ -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 +4 -0

index aa6d84d8848e..868d65c869cd 100644
@@ -1008,6 +1008,10 @@ 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_req_subsys(req)->type == NVME_NQN_DISC)
            return nvmet_parse_discovery_cmd(req);

   diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c new file mode 100644
index 000000000000..7247a7b97644

drivers/nvme/target/auth.c new file +22 -0

@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe over Fabrics DH-HMAC-CHAP authentication.
+ * Copyright (c) 2020 Hannes Reinecke, SUSE Software Solutions.
+ * All rights reserved.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <crypto/hash.h>
+#include <linux/crc32.h>
+#include <linux/base64.h>
+#include <linux/ctype.h>
+#include <linux/random.h>
+#include <asm/unaligned.h>
+
+#include "nvmet.h"
+#include "../host/auth.h"
+
+int nvmet_auth_set_host_key(struct nvmet_host *host, const char

*secret)
+{
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &host->dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (host->dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             host->dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (host->dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(host->dhchap_key_hash);

drivers/nvme/target/auth.c new file +23 -0

+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            host->dhchap_key_hash = -1;
+            return -ENOTSUPP;
+        }
+        /* Use this hash as default */
+        if (!host->dhchap_hash_id)
+            host->dhchap_hash_id = host->dhchap_key_hash;
+    }
+    host->dhchap_secret = kstrdup(secret, GFP_KERNEL);
+    if (!host->dhchap_secret)
+        return -ENOMEM;
+    /* Default to SHA256 */
+    if (!host->dhchap_hash_id)
+        host->dhchap_hash_id = NVME_AUTH_DHCHAP_SHA256;
+
+    pr_debug("Using hash %s\n",
+         nvme_auth_hmac_name(host->dhchap_hash_id));
+    return 0;
+}
+
+int nvmet_auth_set_ctrl_key(struct nvmet_host *host, const char

*secret)

drivers/nvme/target/auth.c new file +82 -0

+{
+    unsigned char dhchap_key_hash;
+
+    if (sscanf(secret, "DHHC-1:%hhd:%*s", &dhchap_key_hash) != 1)
+        return -EINVAL;
+    if (dhchap_key_hash > 3) {
+        pr_warn("Invalid DH-HMAC-CHAP hash id %d\n",
+             dhchap_key_hash);
+        return -EINVAL;
+    }
+    if (dhchap_key_hash > 0) {
+        /* Validate selected hash algorithm */
+        const char *hmac = nvme_auth_hmac_name(dhchap_key_hash);
+
+        if (!crypto_has_shash(hmac, 0, 0)) {
+            pr_err("DH-HMAC-CHAP hash %s unsupported\n", hmac);
+            return -ENOTSUPP;
+        }
+    }
+    host->dhchap_ctrl_secret = kstrdup(secret, GFP_KERNEL);
+    return host->dhchap_ctrl_secret ? 0 : -ENOMEM;
+}
+
+int nvmet_setup_auth(struct nvmet_ctrl *ctrl)
+{
+    int ret = 0;
+    struct nvmet_host_link *p;
+    struct nvmet_host *host = NULL;
+    const char *hash_name;
+
+    down_read(&nvmet_config_sem);
+    if (ctrl->subsys->type == NVME_NQN_DISC)
+        goto out_unlock;
+
+    if (ctrl->subsys->allow_any_host)
+        goto out_unlock;
+
+    list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
+        pr_debug("check %s\n", nvmet_host_name(p->host));
+        if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
+            continue;
+        host = p->host;
+        break;
+    }
+    if (!host) {
+        pr_debug("host %s not found\n", ctrl->hostnqn);
+        ret = -EPERM;
+        goto out_unlock;
+    }
+    if (!host->dhchap_secret) {
+        pr_debug("No authentication provided\n");
+        goto out_unlock;
+    }
+
+    if (ctrl->shash_tfm) {
+        if (host->dhchap_hash_id == ctrl->shash_id) {
+            pr_debug("Re-use existing hash ID %d\n",
+                 ctrl->shash_id);
+            goto out_unlock;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+    }
+
+    hash_name = nvme_auth_hmac_name(host->dhchap_hash_id);
+    if (!hash_name) {
+        pr_warn("Hash ID %d invalid\n", host->dhchap_hash_id);
+        ret = -EINVAL;
+        goto out_unlock;
+    }
+    ctrl->shash_tfm = crypto_alloc_shash(hash_name, 0,
+                         CRYPTO_ALG_ALLOCATES_MEMORY);
+    if (IS_ERR(ctrl->shash_tfm)) {
+        pr_err("failed to allocate shash %s\n", hash_name);
+        ret = PTR_ERR(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        goto out_unlock;
+    }
+    ctrl->shash_id = host->dhchap_hash_id;
+
+    /* Skip the 'DHHC-1:XX:' prefix */
+    ctrl->dhchap_key = nvme_auth_extract_secret(host->dhchap_secret +

10,
+                            &ctrl->dhchap_key_len);
+    if (IS_ERR(ctrl->dhchap_key)) {
+        ret = PTR_ERR(ctrl->dhchap_key);
+        pr_debug("failed to extract host key, error %d\n", ret); +        ctrl->dhchap_key = NULL;
+        goto out_free_hash;
+    }
+    pr_debug("%s: using key %*ph\n", __func__,
+         (int)ctrl->dhchap_key_len, ctrl->dhchap_key);

drivers/nvme/target/auth.c new file +5 -0

+
+    if (!host->dhchap_ctrl_secret)
+        goto out_unlock;
+
+    ctrl->dhchap_ctrl_key =

nvme_auth_extract_secret(host->dhchap_ctrl_secret + 10, +                             &ctrl->dhchap_ctrl_key_len); +    if (IS_ERR(ctrl->dhchap_ctrl_key)) {
+        ret = PTR_ERR(ctrl->dhchap_ctrl_key);
+        pr_debug("failed to extract ctrl key, error %d\n", ret); +        ctrl->dhchap_ctrl_key = NULL;
+    }

drivers/nvme/target/auth.c new file +60 -0

+
+out_free_hash:
+    if (ret) {
+        if (ctrl->dhchap_key) {
+            kfree_sensitive(ctrl->dhchap_key);
+            ctrl->dhchap_key = NULL;
+        }
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+out_unlock:
+    up_read(&nvmet_config_sem);
+
+    return ret;
+}
+
+void nvmet_auth_sq_free(struct nvmet_sq *sq)
+{
+    kfree(sq->dhchap_c1);
+    sq->dhchap_c1 = NULL;
+    kfree(sq->dhchap_c2);
+    sq->dhchap_c2 = NULL;
+    kfree(sq->dhchap_skey);
+    sq->dhchap_skey = NULL;
+}
+
+void nvmet_destroy_auth(struct nvmet_ctrl *ctrl)
+{
+    if (ctrl->shash_tfm) {
+        crypto_free_shash(ctrl->shash_tfm);
+        ctrl->shash_tfm = NULL;
+        ctrl->shash_id = 0;
+    }
+    if (ctrl->dhchap_key) {
+        kfree_sensitive(ctrl->dhchap_key);
+        ctrl->dhchap_key = NULL;
+    }
+    if (ctrl->dhchap_ctrl_key) {
+        kfree_sensitive(ctrl->dhchap_ctrl_key);
+        ctrl->dhchap_ctrl_key = NULL;
+    }
+}
+
+bool nvmet_check_auth_status(struct nvmet_req *req)
+{
+    if (req->sq->ctrl->shash_tfm &&
+        !req->sq->authenticated)
+        return false;
+    return true;
+}
+
+int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
+             unsigned int shash_len)
+{
+    struct nvmet_ctrl *ctrl = req->sq->ctrl;
+    SHASH_DESC_ON_STACK(shash, ctrl->shash_tfm);
+    u8 *challenge = req->sq->dhchap_c1, *host_response;
+    u8 buf[4];
+    int ret;

Quoted 9 lines

Quoted 3 lines

+
+    if (shash_len != ctrl->dhchap_key_len)
+        return -EINVAL;

Is this condition correct? the shash_len is sent by the host and afaict the host is setting it by what the controller sent in the challenge. the ctrl->dhchap_key_len is taken from nvme_auth_extract_secret.

Ideally, but shash_len is actually sent by the host, so it _might_ be different (as it's picked up from the command sent by the host).

Quoted 7 lines

Quoted 3 lines

In other words, if the nvmet host is set to use hmac(sha512) then authentication fails, regardless of the key.

Nope. The hash algorithm is figured out the 'negotiation' step, so the host _should_ have set the correct hash length. But as this is networking you should be validating each field in the received packet to ensure it matches what you expect.

On the target:

# grep -r ''
/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress\:uuid\:b73ff014-2723-4114-aa8d-2f784ecba4f4/

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_dhgroup:null

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_hash:hmac(sha512)

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_ctrl_key:

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_key:DHHC-1:03:KUwVlIUo627Pn05W/lRL2XD57kzIs1yZzJWdd2vgZJUC74kr:

On the host:

# ./nvme connect-all
--dhchap-secret="DHHC-1:03:KUwVlIUo627Pn05W/lRL2XD57kzIs1yZzJWdd2vgZJUC74kr:"

failed to connect controller, error 5

On the target dmesg:

[ 8695.716117] nvmet: creating controller 1 for subsystem
nqn.2014-08.org.nvmexpress.discovery for NQN
nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4.
[ 8695.749996] nvmet: creating controller 2 for subsystem testnqn1 for
NQN nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4
with DH-HMAC-CHAP.
[ 8695.755361] nvmet: ctrl 2 qid 0 failure1 (1)
[ 8695.755449] nvmet: ctrl 2 fatal error occurred!

On the host dmesg:

[ 8781.616712] nvme nvme1: new ctrl: NQN
"nqn.2014-08.org.nvmexpress.discovery", addr 192.168.123.1:8009
[ 8781.637954] nvme nvme2: qid 0: authentication failed
[ 8781.638084] nvme nvme2: failed to connect queue: 0 ret=401

If I change the dhchap_hash to hmac(sha256) authentication succeeds. The failure with hmac(sha512) comes from the above condition as the host is sending key length 64 and nvmet is expecting 32.

Quoted 31 lines

On the target:

# grep -r ''
/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress\:uuid\:b73ff014-2723-4114-aa8d-2f784ecba4f4/

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_dhgroup:null

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_hash:hmac(sha512)

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_ctrl_key:

/sys/kernel/config/nvmet/hosts/nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4/dhchap_key:DHHC-1:03:KUwVlIUo627Pn05W/lRL2XD57kzIs1yZzJWdd2vgZJUC74kr:

On the host:

# ./nvme connect-all
--dhchap-secret="DHHC-1:03:KUwVlIUo627Pn05W/lRL2XD57kzIs1yZzJWdd2vgZJUC74kr:"

failed to connect controller, error 5

On the target dmesg:

[ 8695.716117] nvmet: creating controller 1 for subsystem
nqn.2014-08.org.nvmexpress.discovery for NQN
nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4.
[ 8695.749996] nvmet: creating controller 2 for subsystem testnqn1 for
NQN nqn.2014-08.org.nvmexpress:uuid:b73ff014-2723-4114-aa8d-2f784ecba4f4
with DH-HMAC-CHAP.
[ 8695.755361] nvmet: ctrl 2 qid 0 failure1 (1)
[ 8695.755449] nvmet: ctrl 2 fatal error occurred!

On the host dmesg:

Quoted 8 lines

[ 8781.616712] nvme nvme1: new ctrl: NQN
"nqn.2014-08.org.nvmexpress.discovery", addr 192.168.123.1:8009
[ 8781.637954] nvme nvme2: qid 0: authentication failed
[ 8781.638084] nvme nvme2: failed to connect queue: 0 ret=401

If I change the dhchap_hash to hmac(sha256) authentication succeeds. The failure with hmac(sha512) comes from the above condition as the host is sending key length 64 and nvmet is expecting 32.

A-ha. That shouldn't have happened; selecting the hash on the target was _supposed_ to be reflected to the host.

You did mention something about blocktests; guess I'll need to bite the bullet and actually implement something there.

Hi all,

recent updates to the NVMe spec have added definitions for in-band authentication, and seeing that it provides some real benefit especially for NVMe-TCP here's an attempt to implement it.

Tricky bit here is that the specification orients itself on TLS 1.3, but supports only the FFDHE groups. Which of course the kernel doesn't support. I've been able to come up with a patch for this, but as this is my first attempt to fix anything in the crypto area I would invite people more familiar with these matters to have a look.

Also note that this is just for in-band authentication. Secure concatenation (ie starting TLS with the negotiated parameters) is not implemented; one would need to update the kernel TLS implementation for this, which at this time is beyond scope.

As usual, comments and reviews are welcome.

Changes to v3:
- Renamed parameter to 'dhchap_ctrl_key'
- Fixed bi-directional authentication
- Included reviews from Sagi
- Fixed base64 algorithm for transport encoding

Changes to v2:
- Dropped non-standard algorithms
- Reworked base64 based on fs/crypto/fname.c
- Fixup crash with no keys

Changes to the original submission:
- Included reviews from Vladislav
- Included reviews from Sagi
- Implemented re-authentication support
- Fixed up key handling

Hannes Reinecke (12):
crypto: add crypto_has_shash()
crypto: add crypto_has_kpp()
crypto/ffdhe: Finite Field DH Ephemeral Parameters lib/base64: RFC4648-compliant base64 encoding
nvme: add definitions for NVMe In-Band authentication
nvme-fabrics: decode 'authentication required' connect error
nvme: Implement In-Band authentication
nvme-auth: Diffie-Hellman key exchange support
nvmet: Parse fabrics commands on all queues
nvmet: Implement basic In-Band Authentication
nvmet-auth: Diffie-Hellman key exchange support
nvmet-auth: expire authentication sessions

crypto/Kconfig                         |    8 +
crypto/Makefile                        |    1 +
crypto/ffdhe_helper.c                  |  880 ++++++++++++++
crypto/kpp.c                           |    6 +
crypto/shash.c                         |    6 +
drivers/nvme/host/Kconfig              |   12 +
drivers/nvme/host/Makefile             |    1 +
drivers/nvme/host/auth.c               | 1501 ++++++++++++++++++++++++
drivers/nvme/host/auth.h               |   33 +
drivers/nvme/host/core.c               |  126 +-
drivers/nvme/host/fabrics.c            |   85 +-
drivers/nvme/host/fabrics.h            |    7 +
drivers/nvme/host/nvme.h               |   33 +
drivers/nvme/host/trace.c              |   32 +
drivers/nvme/target/Kconfig            |   12 +
drivers/nvme/target/Makefile           |    1 +
drivers/nvme/target/admin-cmd.c        |    4 +
drivers/nvme/target/auth.c             |  486 ++++++++
drivers/nvme/target/configfs.c         |  133 ++-
drivers/nvme/target/core.c             |   10 +
drivers/nvme/target/fabrics-cmd-auth.c |  507 ++++++++
drivers/nvme/target/fabrics-cmd.c      |   30 +-
drivers/nvme/target/nvmet.h            |   74 ++
include/crypto/ffdhe.h                 |   24 +
include/crypto/hash.h                  |    2 +
include/crypto/kpp.h                   |    2 +
include/linux/base64.h                 |   16 +
include/linux/nvme.h                   |  186 ++-
lib/Makefile                           |    2 +-
lib/base64.c                           |  100 ++
30 files changed, 4309 insertions(+), 11 deletions(-)

create mode 100644 crypto/ffdhe_helper.c
create mode 100644 drivers/nvme/host/auth.c create mode 100644 drivers/nvme/host/auth.h create mode 100644 drivers/nvme/target/auth.c create mode 100644 drivers/nvme/target/fabrics-cmd-auth.c create mode 100644 include/crypto/ffdhe.h
create mode 100644 include/linux/base64.h
create mode 100644 lib/base64.c

Signature · 7 lines

2.29.2


_______________________________________________
Linux-nvme mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-nvme