summaryrefslogtreecommitdiff
path: root/drivers/nvme/common/auth.c
diff options
context:
space:
mode:
authorHannes Reinecke <hare@suse.de>2022-06-27 12:52:02 +0300
committerJens Axboe <axboe@kernel.dk>2022-08-03 02:14:49 +0300
commitf50fff73d620cd6e8f48bc58d4f1c944615a3fea (patch)
treee09610be62695593249b54f2081d954cffcf2f27 /drivers/nvme/common/auth.c
parent3bf2fde6fcc49ccc899cd2a853888823662ccd4c (diff)
downloadlinux-f50fff73d620cd6e8f48bc58d4f1c944615a3fea.tar.xz
nvme: implement In-Band authentication
Implement NVMe-oF In-Band authentication according to NVMe TPAR 8006. This patch adds two new fabric options 'dhchap_secret' to specify the pre-shared key (in ASCII respresentation according to NVMe 2.0 section 8.13.5.8 'Secret representation') and 'dhchap_ctrl_secret' to specify the pre-shared controller key for bi-directional authentication of both the host and the controller. Re-authentication can be triggered by writing the PSK into the new controller sysfs attribute 'dhchap_secret' or 'dhchap_ctrl_secret'. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> [axboe: fold in clang build fix] Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/nvme/common/auth.c')
-rw-r--r--drivers/nvme/common/auth.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
new file mode 100644
index 000000000000..adb43d341ffb
--- /dev/null
+++ b/drivers/nvme/common/auth.c
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 Hannes Reinecke, SUSE Linux
+ */
+
+#include <linux/module.h>
+#include <linux/crc32.h>
+#include <linux/base64.h>
+#include <linux/prandom.h>
+#include <linux/scatterlist.h>
+#include <asm/unaligned.h>
+#include <crypto/hash.h>
+#include <crypto/dh.h>
+#include <linux/nvme.h>
+#include <linux/nvme-auth.h>
+
+static u32 nvme_dhchap_seqnum;
+static DEFINE_MUTEX(nvme_dhchap_mutex);
+
+u32 nvme_auth_get_seqnum(void)
+{
+ u32 seqnum;
+
+ mutex_lock(&nvme_dhchap_mutex);
+ if (!nvme_dhchap_seqnum)
+ nvme_dhchap_seqnum = prandom_u32();
+ else {
+ nvme_dhchap_seqnum++;
+ if (!nvme_dhchap_seqnum)
+ nvme_dhchap_seqnum++;
+ }
+ seqnum = nvme_dhchap_seqnum;
+ mutex_unlock(&nvme_dhchap_mutex);
+ return seqnum;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_get_seqnum);
+
+static struct nvme_auth_dhgroup_map {
+ const char name[16];
+ const char kpp[16];
+} dhgroup_map[] = {
+ [NVME_AUTH_DHGROUP_NULL] = {
+ .name = "null", .kpp = "null" },
+ [NVME_AUTH_DHGROUP_2048] = {
+ .name = "ffdhe2048", .kpp = "ffdhe2048(dh)" },
+ [NVME_AUTH_DHGROUP_3072] = {
+ .name = "ffdhe3072", .kpp = "ffdhe3072(dh)" },
+ [NVME_AUTH_DHGROUP_4096] = {
+ .name = "ffdhe4096", .kpp = "ffdhe4096(dh)" },
+ [NVME_AUTH_DHGROUP_6144] = {
+ .name = "ffdhe6144", .kpp = "ffdhe6144(dh)" },
+ [NVME_AUTH_DHGROUP_8192] = {
+ .name = "ffdhe8192", .kpp = "ffdhe8192(dh)" },
+};
+
+const char *nvme_auth_dhgroup_name(u8 dhgroup_id)
+{
+ if (dhgroup_id > ARRAY_SIZE(dhgroup_map))
+ return NULL;
+ return dhgroup_map[dhgroup_id].name;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);
+
+const char *nvme_auth_dhgroup_kpp(u8 dhgroup_id)
+{
+ if (dhgroup_id > ARRAY_SIZE(dhgroup_map))
+ return NULL;
+ return dhgroup_map[dhgroup_id].kpp;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);
+
+u8 nvme_auth_dhgroup_id(const char *dhgroup_name)
+{
+ int i;
+
+ if (!dhgroup_name || !strlen(dhgroup_name))
+ return NVME_AUTH_DHGROUP_INVALID;
+ for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
+ if (!strlen(dhgroup_map[i].name))
+ continue;
+ if (!strncmp(dhgroup_map[i].name, dhgroup_name,
+ strlen(dhgroup_map[i].name)))
+ return i;
+ }
+ return NVME_AUTH_DHGROUP_INVALID;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);
+
+static struct nvme_dhchap_hash_map {
+ int len;
+ const char hmac[15];
+ const char digest[8];
+} hash_map[] = {
+ [NVME_AUTH_HASH_SHA256] = {
+ .len = 32,
+ .hmac = "hmac(sha256)",
+ .digest = "sha256",
+ },
+ [NVME_AUTH_HASH_SHA384] = {
+ .len = 48,
+ .hmac = "hmac(sha384)",
+ .digest = "sha384",
+ },
+ [NVME_AUTH_HASH_SHA512] = {
+ .len = 64,
+ .hmac = "hmac(sha512)",
+ .digest = "sha512",
+ },
+};
+
+const char *nvme_auth_hmac_name(u8 hmac_id)
+{
+ if (hmac_id > ARRAY_SIZE(hash_map))
+ return NULL;
+ return hash_map[hmac_id].hmac;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_hmac_name);
+
+const char *nvme_auth_digest_name(u8 hmac_id)
+{
+ if (hmac_id > ARRAY_SIZE(hash_map))
+ return NULL;
+ return hash_map[hmac_id].digest;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_digest_name);
+
+u8 nvme_auth_hmac_id(const char *hmac_name)
+{
+ int i;
+
+ if (!hmac_name || !strlen(hmac_name))
+ return NVME_AUTH_HASH_INVALID;
+
+ for (i = 0; i < ARRAY_SIZE(hash_map); i++) {
+ if (!strlen(hash_map[i].hmac))
+ continue;
+ if (!strncmp(hash_map[i].hmac, hmac_name,
+ strlen(hash_map[i].hmac)))
+ return i;
+ }
+ return NVME_AUTH_HASH_INVALID;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_hmac_id);
+
+size_t nvme_auth_hmac_hash_len(u8 hmac_id)
+{
+ if (hmac_id > ARRAY_SIZE(hash_map))
+ return 0;
+ return hash_map[hmac_id].len;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);
+
+struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
+ u8 key_hash)
+{
+ struct nvme_dhchap_key *key;
+ unsigned char *p;
+ u32 crc;
+ int ret, key_len;
+ size_t allocated_len = strlen(secret);
+
+ /* Secret might be affixed with a ':' */
+ p = strrchr(secret, ':');
+ if (p)
+ allocated_len = p - secret;
+ key = kzalloc(sizeof(*key), GFP_KERNEL);
+ if (!key)
+ return ERR_PTR(-ENOMEM);
+ key->key = kzalloc(allocated_len, GFP_KERNEL);
+ if (!key->key) {
+ ret = -ENOMEM;
+ goto out_free_key;
+ }
+
+ key_len = base64_decode(secret, allocated_len, key->key);
+ if (key_len < 0) {
+ pr_debug("base64 key decoding error %d\n",
+ key_len);
+ ret = key_len;
+ goto out_free_secret;
+ }
+
+ if (key_len != 36 && key_len != 52 &&
+ key_len != 68) {
+ pr_err("Invalid key len %d\n", key_len);
+ ret = -EINVAL;
+ goto out_free_secret;
+ }
+
+ if (key_hash > 0 &&
+ (key_len - 4) != nvme_auth_hmac_hash_len(key_hash)) {
+ pr_err("Mismatched key len %d for %s\n", key_len,
+ nvme_auth_hmac_name(key_hash));
+ ret = -EINVAL;
+ goto out_free_secret;
+ }
+
+ /* The last four bytes is the CRC in little-endian format */
+ key_len -= 4;
+ /*
+ * The linux implementation doesn't do pre- and post-increments,
+ * so we have to do it manually.
+ */
+ crc = ~crc32(~0, key->key, key_len);
+
+ if (get_unaligned_le32(key->key + key_len) != crc) {
+ pr_err("key crc mismatch (key %08x, crc %08x)\n",
+ get_unaligned_le32(key->key + key_len), crc);
+ ret = -EKEYREJECTED;
+ goto out_free_secret;
+ }
+ key->len = key_len;
+ key->hash = key_hash;
+ return key;
+out_free_secret:
+ kfree_sensitive(key->key);
+out_free_key:
+ kfree(key);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(nvme_auth_extract_key);
+
+void nvme_auth_free_key(struct nvme_dhchap_key *key)
+{
+ if (!key)
+ return;
+ kfree_sensitive(key->key);
+ kfree(key);
+}
+EXPORT_SYMBOL_GPL(nvme_auth_free_key);
+
+u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
+{
+ const char *hmac_name;
+ struct crypto_shash *key_tfm;
+ struct shash_desc *shash;
+ u8 *transformed_key;
+ int ret;
+
+ if (!key || !key->key) {
+ pr_warn("No key specified\n");
+ return ERR_PTR(-ENOKEY);
+ }
+ if (key->hash == 0) {
+ transformed_key = kmemdup(key->key, key->len, GFP_KERNEL);
+ return transformed_key ? transformed_key : ERR_PTR(-ENOMEM);
+ }
+ hmac_name = nvme_auth_hmac_name(key->hash);
+ if (!hmac_name) {
+ pr_warn("Invalid key hash id %d\n", key->hash);
+ return ERR_PTR(-EINVAL);
+ }
+
+ key_tfm = crypto_alloc_shash(hmac_name, 0, 0);
+ if (IS_ERR(key_tfm))
+ return (u8 *)key_tfm;
+
+ shash = kmalloc(sizeof(struct shash_desc) +
+ crypto_shash_descsize(key_tfm),
+ GFP_KERNEL);
+ if (!shash) {
+ ret = -ENOMEM;
+ goto out_free_key;
+ }
+
+ transformed_key = kzalloc(crypto_shash_digestsize(key_tfm), GFP_KERNEL);
+ if (!transformed_key) {
+ ret = -ENOMEM;
+ goto out_free_shash;
+ }
+
+ shash->tfm = key_tfm;
+ ret = crypto_shash_setkey(key_tfm, key->key, key->len);
+ if (ret < 0)
+ goto out_free_shash;
+ ret = crypto_shash_init(shash);
+ if (ret < 0)
+ goto out_free_shash;
+ ret = crypto_shash_update(shash, nqn, strlen(nqn));
+ if (ret < 0)
+ goto out_free_shash;
+ ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
+ if (ret < 0)
+ goto out_free_shash;
+ ret = crypto_shash_final(shash, transformed_key);
+out_free_shash:
+ kfree(shash);
+out_free_key:
+ crypto_free_shash(key_tfm);
+ if (ret < 0) {
+ kfree_sensitive(transformed_key);
+ return ERR_PTR(ret);
+ }
+ return transformed_key;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_transform_key);
+
+int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key)
+{
+ struct nvme_dhchap_key *key;
+ u8 key_hash;
+
+ if (!secret) {
+ *ret_key = NULL;
+ return 0;
+ }
+
+ if (sscanf(secret, "DHHC-1:%hhd:%*s:", &key_hash) != 1)
+ return -EINVAL;
+
+ /* Pass in the secret without the 'DHHC-1:XX:' prefix */
+ key = nvme_auth_extract_key(secret + 10, key_hash);
+ if (IS_ERR(key)) {
+ *ret_key = NULL;
+ return PTR_ERR(key);
+ }
+
+ *ret_key = key;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_generate_key);
+
+MODULE_LICENSE("GPL v2");