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authorStephan Müller <smueller@chronox.de>2021-11-19 09:55:58 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2021-11-26 08:25:17 +0300
commit026a733e66592e743a0905c7fd6b5d3bf89b2d7e (patch)
tree017fa67b601ebc24efc2c9bd8ccf4b6d074d2747 /crypto
parentb808f32023dd8127b0fa27f60fa69a959fd70388 (diff)
downloadlinux-026a733e66592e743a0905c7fd6b5d3bf89b2d7e.tar.xz
crypto: kdf - add SP800-108 counter key derivation function
SP800-108 defines three KDFs - this patch provides the counter KDF implementation. The KDF is implemented as a service function where the caller has to maintain the hash / HMAC state. Apart from this hash/HMAC state, no additional state is required to be maintained by either the caller or the KDF implementation. The key for the KDF is set with the crypto_kdf108_setkey function which is intended to be invoked before the caller requests a key derivation operation via crypto_kdf108_ctr_generate. SP800-108 allows the use of either a HMAC or a hash as crypto primitive for the KDF. When a HMAC primtive is intended to be used, crypto_kdf108_setkey must be used to set the HMAC key. Otherwise, for a hash crypto primitve crypto_kdf108_ctr_generate can be used immediately after allocating the hash handle. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/Kconfig4
-rw-r--r--crypto/Makefile5
-rw-r--r--crypto/kdf_sp800108.c153
3 files changed, 162 insertions, 0 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 285f82647d2b..01b9ca0836a5 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1845,6 +1845,10 @@ config CRYPTO_JITTERENTROPY
random numbers. This Jitterentropy RNG registers with
the kernel crypto API and can be used by any caller.
+config CRYPTO_KDF800108_CTR
+ tristate
+ select CRYPTO_HASH
+
config CRYPTO_USER_API
tristate
diff --git a/crypto/Makefile b/crypto/Makefile
index 429c4d57458c..d76bff8d0ffd 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -200,3 +200,8 @@ obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys/
obj-$(CONFIG_CRYPTO_HASH_INFO) += hash_info.o
crypto_simd-y := simd.o
obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o
+
+#
+# Key derivation function
+#
+obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o
diff --git a/crypto/kdf_sp800108.c b/crypto/kdf_sp800108.c
new file mode 100644
index 000000000000..58edf7797abf
--- /dev/null
+++ b/crypto/kdf_sp800108.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * SP800-108 Key-derivation function
+ *
+ * Copyright (C) 2021, Stephan Mueller <smueller@chronox.de>
+ */
+
+#include <linux/fips.h>
+#include <linux/module.h>
+#include <crypto/kdf_sp800108.h>
+#include <crypto/internal/kdf_selftest.h>
+
+/*
+ * SP800-108 CTR KDF implementation
+ */
+int crypto_kdf108_ctr_generate(struct crypto_shash *kmd,
+ const struct kvec *info, unsigned int info_nvec,
+ u8 *dst, unsigned int dlen)
+{
+ SHASH_DESC_ON_STACK(desc, kmd);
+ __be32 counter = cpu_to_be32(1);
+ const unsigned int h = crypto_shash_digestsize(kmd), dlen_orig = dlen;
+ unsigned int i;
+ int err = 0;
+ u8 *dst_orig = dst;
+
+ desc->tfm = kmd;
+
+ while (dlen) {
+ err = crypto_shash_init(desc);
+ if (err)
+ goto out;
+
+ err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
+ if (err)
+ goto out;
+
+ for (i = 0; i < info_nvec; i++) {
+ err = crypto_shash_update(desc, info[i].iov_base,
+ info[i].iov_len);
+ if (err)
+ goto out;
+ }
+
+ if (dlen < h) {
+ u8 tmpbuffer[HASH_MAX_DIGESTSIZE];
+
+ err = crypto_shash_final(desc, tmpbuffer);
+ if (err)
+ goto out;
+ memcpy(dst, tmpbuffer, dlen);
+ memzero_explicit(tmpbuffer, h);
+ goto out;
+ }
+
+ err = crypto_shash_final(desc, dst);
+ if (err)
+ goto out;
+
+ dlen -= h;
+ dst += h;
+ counter = cpu_to_be32(be32_to_cpu(counter) + 1);
+ }
+
+out:
+ if (err)
+ memzero_explicit(dst_orig, dlen_orig);
+ shash_desc_zero(desc);
+ return err;
+}
+EXPORT_SYMBOL(crypto_kdf108_ctr_generate);
+
+/*
+ * The seeding of the KDF
+ */
+int crypto_kdf108_setkey(struct crypto_shash *kmd,
+ const u8 *key, size_t keylen,
+ const u8 *ikm, size_t ikmlen)
+{
+ unsigned int ds = crypto_shash_digestsize(kmd);
+
+ /* SP800-108 does not support IKM */
+ if (ikm || ikmlen)
+ return -EINVAL;
+
+ /* Check according to SP800-108 section 7.2 */
+ if (ds > keylen)
+ return -EINVAL;
+
+ /* Set the key for the MAC used for the KDF. */
+ return crypto_shash_setkey(kmd, key, keylen);
+}
+EXPORT_SYMBOL(crypto_kdf108_setkey);
+
+/*
+ * Test vector obtained from
+ * http://csrc.nist.gov/groups/STM/cavp/documents/KBKDF800-108/CounterMode.zip
+ */
+static const struct kdf_testvec kdf_ctr_hmac_sha256_tv_template[] = {
+ {
+ .key = "\xdd\x1d\x91\xb7\xd9\x0b\x2b\xd3"
+ "\x13\x85\x33\xce\x92\xb2\x72\xfb"
+ "\xf8\xa3\x69\x31\x6a\xef\xe2\x42"
+ "\xe6\x59\xcc\x0a\xe2\x38\xaf\xe0",
+ .keylen = 32,
+ .ikm = NULL,
+ .ikmlen = 0,
+ .info = {
+ .iov_base = "\x01\x32\x2b\x96\xb3\x0a\xcd\x19"
+ "\x79\x79\x44\x4e\x46\x8e\x1c\x5c"
+ "\x68\x59\xbf\x1b\x1c\xf9\x51\xb7"
+ "\xe7\x25\x30\x3e\x23\x7e\x46\xb8"
+ "\x64\xa1\x45\xfa\xb2\x5e\x51\x7b"
+ "\x08\xf8\x68\x3d\x03\x15\xbb\x29"
+ "\x11\xd8\x0a\x0e\x8a\xba\x17\xf3"
+ "\xb4\x13\xfa\xac",
+ .iov_len = 60
+ },
+ .expected = "\x10\x62\x13\x42\xbf\xb0\xfd\x40"
+ "\x04\x6c\x0e\x29\xf2\xcf\xdb\xf0",
+ .expectedlen = 16
+ }
+};
+
+static int __init crypto_kdf108_init(void)
+{
+ int ret = kdf_test(&kdf_ctr_hmac_sha256_tv_template[0], "hmac(sha256)",
+ crypto_kdf108_setkey, crypto_kdf108_ctr_generate);
+
+ if (ret) {
+ if (fips_enabled)
+ panic("alg: self-tests for CTR-KDF (hmac(sha256)) failed (rc=%d)\n",
+ ret);
+
+ WARN(1,
+ "alg: self-tests for CTR-KDF (hmac(sha256)) failed (rc=%d)\n",
+ ret);
+ } else {
+ pr_info("alg: self-tests for CTR-KDF (hmac(sha256)) passed\n");
+ }
+
+ return ret;
+}
+
+static void __exit crypto_kdf108_exit(void) { }
+
+module_init(crypto_kdf108_init);
+module_exit(crypto_kdf108_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("Key Derivation Function conformant to SP800-108");