From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/nvme/common/auth.c | 781 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 781 insertions(+) create mode 100644 drivers/nvme/common/auth.c (limited to 'drivers/nvme/common/auth.c') diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c new file mode 100644 index 000000000..e2e0c7365 --- /dev/null +++ b/drivers/nvme/common/auth.c @@ -0,0 +1,781 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2020 Hannes Reinecke, SUSE Linux + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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 = get_random_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 const struct nvme_auth_dhgroup_map { + char name[16]; + 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 const struct nvme_dhchap_hash_map { + int len; + char hmac[15]; +} hash_map[] = { + [NVME_AUTH_HASH_SHA256] = { + .len = 32, + .hmac = "hmac(sha256)", + }, + [NVME_AUTH_HASH_SHA384] = { + .len = 48, + .hmac = "hmac(sha384)", + }, + [NVME_AUTH_HASH_SHA512] = { + .len = 64, + .hmac = "hmac(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); + +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); + +u32 nvme_auth_key_struct_size(u32 key_len) +{ + struct nvme_dhchap_key key; + + return struct_size(&key, key, key_len); +} +EXPORT_SYMBOL_GPL(nvme_auth_key_struct_size); + +struct nvme_dhchap_key *nvme_auth_extract_key(const char *secret, u8 key_hash) +{ + struct nvme_dhchap_key *key; + const 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 = nvme_auth_alloc_key(allocated_len, 0); + if (!key) + return ERR_PTR(-ENOMEM); + + key_len = base64_decode(secret, allocated_len, key->key, true, BASE64_STD); + if (key_len < 0) { + pr_debug("base64 key decoding error %d\n", + key_len); + ret = key_len; + goto out_free_key; + } + + if (key_len != 36 && key_len != 52 && + key_len != 68) { + pr_err("Invalid key len %d\n", key_len); + ret = -EINVAL; + goto out_free_key; + } + + /* 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_key; + } + key->len = key_len; + key->hash = key_hash; + return key; +out_free_key: + nvme_auth_free_key(key); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(nvme_auth_extract_key); + +struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash) +{ + u32 num_bytes = nvme_auth_key_struct_size(len); + struct nvme_dhchap_key *key = kzalloc(num_bytes, GFP_KERNEL); + + if (key) { + key->len = len; + key->hash = hash; + } + return key; +} +EXPORT_SYMBOL_GPL(nvme_auth_alloc_key); + +void nvme_auth_free_key(struct nvme_dhchap_key *key) +{ + if (!key) + return; + kfree_sensitive(key); +} +EXPORT_SYMBOL_GPL(nvme_auth_free_key); + +/* + * Start computing an HMAC value, given the algorithm ID and raw key. + * + * The context should be zeroized at the end of its lifetime. The caller can do + * that implicitly by calling nvme_auth_hmac_final(), or explicitly (needed when + * a context is abandoned without finalizing it) by calling memzero_explicit(). + */ +int nvme_auth_hmac_init(struct nvme_auth_hmac_ctx *hmac, u8 hmac_id, + const u8 *key, size_t key_len) +{ + hmac->hmac_id = hmac_id; + switch (hmac_id) { + case NVME_AUTH_HASH_SHA256: + hmac_sha256_init_usingrawkey(&hmac->sha256, key, key_len); + return 0; + case NVME_AUTH_HASH_SHA384: + hmac_sha384_init_usingrawkey(&hmac->sha384, key, key_len); + return 0; + case NVME_AUTH_HASH_SHA512: + hmac_sha512_init_usingrawkey(&hmac->sha512, key, key_len); + return 0; + } + pr_warn("%s: invalid hash algorithm %d\n", __func__, hmac_id); + return -EINVAL; +} +EXPORT_SYMBOL_GPL(nvme_auth_hmac_init); + +void nvme_auth_hmac_update(struct nvme_auth_hmac_ctx *hmac, const u8 *data, + size_t data_len) +{ + switch (hmac->hmac_id) { + case NVME_AUTH_HASH_SHA256: + hmac_sha256_update(&hmac->sha256, data, data_len); + return; + case NVME_AUTH_HASH_SHA384: + hmac_sha384_update(&hmac->sha384, data, data_len); + return; + case NVME_AUTH_HASH_SHA512: + hmac_sha512_update(&hmac->sha512, data, data_len); + return; + } + /* Unreachable because nvme_auth_hmac_init() validated hmac_id */ + WARN_ON_ONCE(1); +} +EXPORT_SYMBOL_GPL(nvme_auth_hmac_update); + +/* Finish computing an HMAC value. Note that this zeroizes the HMAC context. */ +void nvme_auth_hmac_final(struct nvme_auth_hmac_ctx *hmac, u8 *out) +{ + switch (hmac->hmac_id) { + case NVME_AUTH_HASH_SHA256: + hmac_sha256_final(&hmac->sha256, out); + return; + case NVME_AUTH_HASH_SHA384: + hmac_sha384_final(&hmac->sha384, out); + return; + case NVME_AUTH_HASH_SHA512: + hmac_sha512_final(&hmac->sha512, out); + return; + } + /* Unreachable because nvme_auth_hmac_init() validated hmac_id */ + WARN_ON_ONCE(1); +} +EXPORT_SYMBOL_GPL(nvme_auth_hmac_final); + +static int nvme_auth_hmac(u8 hmac_id, const u8 *key, size_t key_len, + const u8 *data, size_t data_len, u8 *out) +{ + struct nvme_auth_hmac_ctx hmac; + int ret; + + ret = nvme_auth_hmac_init(&hmac, hmac_id, key, key_len); + if (ret == 0) { + nvme_auth_hmac_update(&hmac, data, data_len); + nvme_auth_hmac_final(&hmac, out); + } + return ret; +} + +static int nvme_auth_hash(u8 hmac_id, const u8 *data, size_t data_len, u8 *out) +{ + switch (hmac_id) { + case NVME_AUTH_HASH_SHA256: + sha256(data, data_len, out); + return 0; + case NVME_AUTH_HASH_SHA384: + sha384(data, data_len, out); + return 0; + case NVME_AUTH_HASH_SHA512: + sha512(data, data_len, out); + return 0; + } + pr_warn("%s: invalid hash algorithm %d\n", __func__, hmac_id); + return -EINVAL; +} + +struct nvme_dhchap_key *nvme_auth_transform_key( + const struct nvme_dhchap_key *key, const char *nqn) +{ + struct nvme_auth_hmac_ctx hmac; + struct nvme_dhchap_key *transformed_key; + int ret, key_len; + + if (!key) { + pr_warn("No key specified\n"); + return ERR_PTR(-ENOKEY); + } + if (key->hash == 0) { + key_len = nvme_auth_key_struct_size(key->len); + transformed_key = kmemdup(key, key_len, GFP_KERNEL); + if (!transformed_key) + return ERR_PTR(-ENOMEM); + return transformed_key; + } + ret = nvme_auth_hmac_init(&hmac, key->hash, key->key, key->len); + if (ret) + return ERR_PTR(ret); + key_len = nvme_auth_hmac_hash_len(key->hash); + transformed_key = nvme_auth_alloc_key(key_len, key->hash); + if (!transformed_key) { + memzero_explicit(&hmac, sizeof(hmac)); + return ERR_PTR(-ENOMEM); + } + nvme_auth_hmac_update(&hmac, nqn, strlen(nqn)); + nvme_auth_hmac_update(&hmac, "NVMe-over-Fabrics", 17); + nvme_auth_hmac_final(&hmac, transformed_key->key); + return transformed_key; +} +EXPORT_SYMBOL_GPL(nvme_auth_transform_key); + +/** + * nvme_auth_augmented_challenge() - Compute the augmented DH-HMAC-CHAP challenge + * @hmac_id: Hash algorithm identifier + * @skey: Session key + * @skey_len: Length of @skey + * @challenge: Challenge value + * @aug: Output buffer for the augmented challenge + * @hlen: Hash output length (length of @challenge and @aug) + * + * NVMe base specification 8.3.5.5.4: The augmented challenge is computed + * applying the HMAC function using the hash function H() selected by the + * HashID parameter ... with the hash of the ephemeral DH key ... as HMAC key + * to the challenge C (i.e., Ca = HMAC(H(g^xy mod p), C)). + * + * As the session key skey is already H(g^xy mod p) per section 8.3.5.5.9, use + * it directly as the HMAC key without additional hashing. + * + * Return: 0 on success, negative errno on failure. + */ +int nvme_auth_augmented_challenge(u8 hmac_id, const u8 *skey, size_t skey_len, + const u8 *challenge, u8 *aug, size_t hlen) +{ + return nvme_auth_hmac(hmac_id, skey, skey_len, challenge, hlen, aug); +} +EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge); + +int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, u8 dh_gid) +{ + int ret; + + ret = crypto_kpp_set_secret(dh_tfm, NULL, 0); + if (ret) + pr_debug("failed to set private key, error %d\n", ret); + + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey); + +int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, + u8 *host_key, size_t host_key_len) +{ + struct kpp_request *req; + struct crypto_wait wait; + struct scatterlist dst; + int ret; + + req = kpp_request_alloc(dh_tfm, GFP_KERNEL); + if (!req) + return -ENOMEM; + + crypto_init_wait(&wait); + kpp_request_set_input(req, NULL, 0); + sg_init_one(&dst, host_key, host_key_len); + kpp_request_set_output(req, &dst, host_key_len); + kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_req_done, &wait); + + ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait); + kpp_request_free(req); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey); + +/** + * nvme_auth_gen_session_key() - Generate an ephemeral session key + * @dh_tfm: Diffie-Hellman transform with local private key already set + * @public_key: Peer's public key + * @public_key_len: Length of @public_key + * @sess_key: Output buffer for the session key + * @sess_key_len: Size of @sess_key buffer + * @hash_id: Hash algorithm identifier + * + * NVMe base specification 8.3.5.5.9: The session key Ks shall be computed from + * the ephemeral DH key (i.e., g^xy mod p) ... by applying the hash function + * H() selected by the HashID parameter ... (i.e., Ks = H(g^xy mod p)). + * + * Return: 0 on success, negative errno on failure. + */ +int nvme_auth_gen_session_key(struct crypto_kpp *dh_tfm, + const u8 *public_key, size_t public_key_len, + u8 *sess_key, size_t sess_key_len, u8 hash_id) +{ + struct kpp_request *req; + struct crypto_wait wait; + struct scatterlist src, dst; + u8 *dh_secret; + size_t dh_secret_len, hash_len; + int ret; + + hash_len = nvme_auth_hmac_hash_len(hash_id); + if (!hash_len) { + pr_warn("%s: invalid hash algorithm %d\n", __func__, hash_id); + return -EINVAL; + } + + if (sess_key_len != hash_len) { + pr_warn("%s: sess_key buffer missized (%zu != %zu)\n", + __func__, sess_key_len, hash_len); + return -EINVAL; + } + + dh_secret_len = crypto_kpp_maxsize(dh_tfm); + dh_secret = kzalloc(dh_secret_len, GFP_KERNEL); + if (!dh_secret) + return -ENOMEM; + + req = kpp_request_alloc(dh_tfm, GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto out_free_secret; + } + + crypto_init_wait(&wait); + sg_init_one(&src, public_key, public_key_len); + kpp_request_set_input(req, &src, public_key_len); + sg_init_one(&dst, dh_secret, dh_secret_len); + kpp_request_set_output(req, &dst, dh_secret_len); + kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_req_done, &wait); + + ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait); + kpp_request_free(req); + + if (ret) + goto out_free_secret; + + ret = nvme_auth_hash(hash_id, dh_secret, dh_secret_len, sess_key); + +out_free_secret: + kfree_sensitive(dh_secret); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_session_key); + +int nvme_auth_parse_key(const char *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_parse_key); + +/** + * nvme_auth_generate_psk - Generate a PSK for TLS + * @hmac_id: Hash function identifier + * @skey: Session key + * @skey_len: Length of @skey + * @c1: Value of challenge C1 + * @c2: Value of challenge C2 + * @hash_len: Hash length of the hash algorithm + * @ret_psk: Pointer to the resulting generated PSK + * @ret_len: length of @ret_psk + * + * Generate a PSK for TLS as specified in NVMe base specification, section + * 8.13.5.9: Generated PSK for TLS + * + * The generated PSK for TLS shall be computed applying the HMAC function + * using the hash function H( ) selected by the HashID parameter in the + * DH-HMAC-CHAP_Challenge message with the session key KS as key to the + * concatenation of the two challenges C1 and C2 (i.e., generated + * PSK = HMAC(KS, C1 || C2)). + * + * Returns 0 on success with a valid generated PSK pointer in @ret_psk and + * the length of @ret_psk in @ret_len, or a negative error number otherwise. + */ +int nvme_auth_generate_psk(u8 hmac_id, const u8 *skey, size_t skey_len, + const u8 *c1, const u8 *c2, size_t hash_len, + u8 **ret_psk, size_t *ret_len) +{ + size_t psk_len = nvme_auth_hmac_hash_len(hmac_id); + struct nvme_auth_hmac_ctx hmac; + u8 *psk; + int ret; + + if (!c1 || !c2) + return -EINVAL; + + ret = nvme_auth_hmac_init(&hmac, hmac_id, skey, skey_len); + if (ret) + return ret; + psk = kzalloc(psk_len, GFP_KERNEL); + if (!psk) { + memzero_explicit(&hmac, sizeof(hmac)); + return -ENOMEM; + } + nvme_auth_hmac_update(&hmac, c1, hash_len); + nvme_auth_hmac_update(&hmac, c2, hash_len); + nvme_auth_hmac_final(&hmac, psk); + *ret_psk = psk; + *ret_len = psk_len; + return 0; +} +EXPORT_SYMBOL_GPL(nvme_auth_generate_psk); + +/** + * nvme_auth_generate_digest - Generate TLS PSK digest + * @hmac_id: Hash function identifier + * @psk: Generated input PSK + * @psk_len: Length of @psk + * @subsysnqn: NQN of the subsystem + * @hostnqn: NQN of the host + * @ret_digest: Pointer to the returned digest + * + * Generate a TLS PSK digest as specified in TP8018 Section 3.6.1.3: + * TLS PSK and PSK identity Derivation + * + * The PSK digest shall be computed by encoding in Base64 (refer to RFC + * 4648) the result of the application of the HMAC function using the hash + * function specified in item 4 above (ie the hash function of the cipher + * suite associated with the PSK identity) with the PSK as HMAC key to the + * concatenation of: + * - the NQN of the host (i.e., NQNh) not including the null terminator; + * - a space character; + * - the NQN of the NVM subsystem (i.e., NQNc) not including the null + * terminator; + * - a space character; and + * - the seventeen ASCII characters "NVMe-over-Fabrics" + * (i.e., = Base64(HMAC(PSK, NQNh || " " || NQNc || " " || + * "NVMe-over-Fabrics"))). + * The length of the PSK digest depends on the hash function used to compute + * it as follows: + * - If the SHA-256 hash function is used, the resulting PSK digest is 44 + * characters long; or + * - If the SHA-384 hash function is used, the resulting PSK digest is 64 + * characters long. + * + * Returns 0 on success with a valid digest pointer in @ret_digest, or a + * negative error number on failure. + */ +int nvme_auth_generate_digest(u8 hmac_id, const u8 *psk, size_t psk_len, + const char *subsysnqn, const char *hostnqn, + char **ret_digest) +{ + struct nvme_auth_hmac_ctx hmac; + u8 digest[NVME_AUTH_MAX_DIGEST_SIZE]; + size_t hash_len = nvme_auth_hmac_hash_len(hmac_id); + char *enc; + size_t enc_len; + int ret; + + if (WARN_ON(!subsysnqn || !hostnqn)) + return -EINVAL; + + if (hash_len == 0) { + pr_warn("%s: invalid hash algorithm %d\n", + __func__, hmac_id); + return -EINVAL; + } + + switch (hash_len) { + case 32: + enc_len = 44; + break; + case 48: + enc_len = 64; + break; + default: + pr_warn("%s: invalid hash algorithm '%s'\n", + __func__, nvme_auth_hmac_name(hmac_id)); + return -EINVAL; + } + + enc = kzalloc(enc_len + 1, GFP_KERNEL); + if (!enc) { + ret = -ENOMEM; + goto out; + } + + ret = nvme_auth_hmac_init(&hmac, hmac_id, psk, psk_len); + if (ret) + goto out; + nvme_auth_hmac_update(&hmac, hostnqn, strlen(hostnqn)); + nvme_auth_hmac_update(&hmac, " ", 1); + nvme_auth_hmac_update(&hmac, subsysnqn, strlen(subsysnqn)); + nvme_auth_hmac_update(&hmac, " NVMe-over-Fabrics", 18); + nvme_auth_hmac_final(&hmac, digest); + + ret = base64_encode(digest, hash_len, enc, true, BASE64_STD); + if (ret < enc_len) { + ret = -ENOKEY; + goto out; + } + *ret_digest = enc; + ret = 0; + +out: + if (ret) + kfree_sensitive(enc); + memzero_explicit(digest, sizeof(digest)); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_generate_digest); + +/** + * nvme_auth_derive_tls_psk - Derive TLS PSK + * @hmac_id: Hash function identifier + * @psk: generated input PSK + * @psk_len: size of @psk + * @psk_digest: TLS PSK digest + * @ret_psk: Pointer to the resulting TLS PSK + * + * Derive a TLS PSK as specified in TP8018 Section 3.6.1.3: + * TLS PSK and PSK identity Derivation + * + * The TLS PSK shall be derived as follows from an input PSK + * (i.e., either a retained PSK or a generated PSK) and a PSK + * identity using the HKDF-Extract and HKDF-Expand-Label operations + * (refer to RFC 5869 and RFC 8446) where the hash function is the + * one specified by the hash specifier of the PSK identity: + * 1. PRK = HKDF-Extract(0, Input PSK); and + * 2. TLS PSK = HKDF-Expand-Label(PRK, "nvme-tls-psk", PskIdentityContext, L), + * where PskIdentityContext is the hash identifier indicated in + * the PSK identity concatenated to a space character and to the + * Base64 PSK digest (i.e., " ") and L is the + * output size in bytes of the hash function (i.e., 32 for SHA-256 + * and 48 for SHA-384). + * + * Returns 0 on success with a valid psk pointer in @ret_psk or a negative + * error number otherwise. + */ +int nvme_auth_derive_tls_psk(int hmac_id, const u8 *psk, size_t psk_len, + const char *psk_digest, u8 **ret_psk) +{ + static const u8 default_salt[NVME_AUTH_MAX_DIGEST_SIZE]; + static const char label[18] = "tls13 nvme-tls-psk"; + u8 prk[NVME_AUTH_MAX_DIGEST_SIZE]; + size_t hash_len, ctx_len; + u8 *hmac_data = NULL, *tls_key; + size_t i; + int ret; + + hash_len = nvme_auth_hmac_hash_len(hmac_id); + if (hash_len == 0) { + pr_warn("%s: invalid hash algorithm %d\n", + __func__, hmac_id); + return -EINVAL; + } + if (hmac_id == NVME_AUTH_HASH_SHA512) { + pr_warn("%s: unsupported hash algorithm %s\n", + __func__, nvme_auth_hmac_name(hmac_id)); + return -EINVAL; + } + + if (psk_len != hash_len) { + pr_warn("%s: unexpected psk_len %zu\n", __func__, psk_len); + return -EINVAL; + } + + /* HKDF-Extract */ + ret = nvme_auth_hmac(hmac_id, default_salt, hash_len, psk, psk_len, + prk); + if (ret) + goto out; + + /* + * HKDF-Expand-Label (RFC 8446 section 7.1), with output length equal to + * the hash length (so only a single HMAC operation is needed) + */ + + hmac_data = kmalloc(/* output length */ 2 + + /* label */ 1 + sizeof(label) + + /* context (max) */ 1 + 3 + 1 + strlen(psk_digest) + + /* counter */ 1, + GFP_KERNEL); + if (!hmac_data) { + ret = -ENOMEM; + goto out; + } + /* output length */ + i = 0; + hmac_data[i++] = hash_len >> 8; + hmac_data[i++] = hash_len; + + /* label */ + static_assert(sizeof(label) <= 255); + hmac_data[i] = sizeof(label); + memcpy(&hmac_data[i + 1], label, sizeof(label)); + i += 1 + sizeof(label); + + /* context */ + ctx_len = sprintf(&hmac_data[i + 1], "%02d %s", hmac_id, psk_digest); + if (ctx_len > 255) { + ret = -EINVAL; + goto out; + } + hmac_data[i] = ctx_len; + i += 1 + ctx_len; + + /* counter (this overwrites the NUL terminator written by sprintf) */ + hmac_data[i++] = 1; + + tls_key = kzalloc(psk_len, GFP_KERNEL); + if (!tls_key) { + ret = -ENOMEM; + goto out; + } + ret = nvme_auth_hmac(hmac_id, prk, hash_len, hmac_data, i, tls_key); + if (ret) { + kfree_sensitive(tls_key); + goto out; + } + *ret_psk = tls_key; +out: + kfree_sensitive(hmac_data); + memzero_explicit(prk, sizeof(prk)); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_derive_tls_psk); + +MODULE_DESCRIPTION("NVMe Authentication framework"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1