Adding upstream version 2:2.3.7.upstream/2%2.3.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 232 insertions, 0 deletions

diff --git a/lib/crypto_backend/pbkdf2_generic.c b/lib/crypto_backend/pbkdf2_generic.c
new file mode 100644
index 0000000..b18c7a7
--- /dev/null
+++ b/lib/crypto_backend/pbkdf2_generic.c
@@ -0,0 +1,232 @@
+/*
+ * Implementation of Password-Based Cryptography as per PKCS#5
+ * Copyright (C) 2002,2003 Simon Josefsson
+ * Copyright (C) 2004 Free Software Foundation
+ *
+ * cryptsetup related changes
+ * Copyright (C) 2012-2021 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2012-2021 Milan Broz
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this file; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <errno.h>
+#include <alloca.h>
+#include "crypto_backend_internal.h"
+
+static int hash_buf(const char *src, size_t src_len,
+		    char *dst, size_t dst_len,
+		    const char *hash_name)
+{
+	struct crypt_hash *hd = NULL;
+	int r;
+
+	if (crypt_hash_init(&hd, hash_name))
+		return -EINVAL;
+
+	r = crypt_hash_write(hd, src, src_len);
+
+	if (!r)
+		r = crypt_hash_final(hd, dst, dst_len);
+
+	crypt_hash_destroy(hd);
+	return r;
+}
+
+/*
+ * 5.2 PBKDF2
+ *
+ *  PBKDF2 applies a pseudorandom function (see Appendix B.1 for an
+ *  example) to derive keys. The length of the derived key is essentially
+ *  unbounded. (However, the maximum effective search space for the
+ *  derived key may be limited by the structure of the underlying
+ *  pseudorandom function. See Appendix B.1 for further discussion.)
+ *  PBKDF2 is recommended for new applications.
+ *
+ *  PBKDF2 (P, S, c, dkLen)
+ *
+ *  Options:        PRF        underlying pseudorandom function (hLen
+ *                             denotes the length in octets of the
+ *                             pseudorandom function output)
+ *
+ *  Input:          P          password, an octet string (ASCII or UTF-8)
+ *                  S          salt, an octet string
+ *                  c          iteration count, a positive integer
+ *                  dkLen      intended length in octets of the derived
+ *                             key, a positive integer, at most
+ *                             (2^32 - 1) * hLen
+ *
+ *  Output:         DK         derived key, a dkLen-octet string
+ */
+
+/*
+ * if hash_block_size is not zero, the HMAC key is pre-hashed
+ * inside this function.
+ * This prevents situation when crypto backend doesn't support
+ * long HMAC keys or it tries hash long key in every iteration
+ * (because of crypt_final() cannot do simple key reset.
+ */
+
+#define MAX_PRF_BLOCK_LEN 80
+
+int pkcs5_pbkdf2(const char *hash,
+			const char *P, size_t Plen,
+			const char *S, size_t Slen,
+			unsigned int c, unsigned int dkLen,
+			char *DK, unsigned int hash_block_size)
+{
+	struct crypt_hmac *hmac;
+	char U[MAX_PRF_BLOCK_LEN];
+	char T[MAX_PRF_BLOCK_LEN];
+	char P_hash[MAX_PRF_BLOCK_LEN];
+	int i, k, rc = -EINVAL;
+	unsigned int u, hLen, l, r;
+	size_t tmplen = Slen + 4;
+	char *tmp;
+
+	tmp = alloca(tmplen);
+	if (tmp == NULL)
+		return -ENOMEM;
+
+	hLen = crypt_hmac_size(hash);
+	if (hLen == 0 || hLen > MAX_PRF_BLOCK_LEN)
+		return -EINVAL;
+
+	if (c == 0)
+		return -EINVAL;
+
+	if (dkLen == 0)
+		return -EINVAL;
+
+	/*
+	 *
+	 *  Steps:
+	 *
+	 *     1. If dkLen > (2^32 - 1) * hLen, output "derived key too long" and
+	 *        stop.
+	 */
+
+	if (dkLen > 4294967295U)
+		return -EINVAL;
+
+	/*
+	 *     2. Let l be the number of hLen-octet blocks in the derived key,
+	 *        rounding up, and let r be the number of octets in the last
+	 *        block:
+	 *
+	 *                  l = CEIL (dkLen / hLen) ,
+	 *                  r = dkLen - (l - 1) * hLen .
+	 *
+	 *        Here, CEIL (x) is the "ceiling" function, i.e. the smallest
+	 *        integer greater than, or equal to, x.
+	 */
+
+	l = dkLen / hLen;
+	if (dkLen % hLen)
+		l++;
+	r = dkLen - (l - 1) * hLen;
+
+	/*
+	 *     3. For each block of the derived key apply the function F defined
+	 *        below to the password P, the salt S, the iteration count c, and
+	 *        the block index to compute the block:
+	 *
+	 *                  T_1 = F (P, S, c, 1) ,
+	 *                  T_2 = F (P, S, c, 2) ,
+	 *                  ...
+	 *                  T_l = F (P, S, c, l) ,
+	 *
+	 *        where the function F is defined as the exclusive-or sum of the
+	 *        first c iterates of the underlying pseudorandom function PRF
+	 *        applied to the password P and the concatenation of the salt S
+	 *        and the block index i:
+	 *
+	 *                  F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
+	 *
+	 *        where
+	 *
+	 *                  U_1 = PRF (P, S || INT (i)) ,
+	 *                  U_2 = PRF (P, U_1) ,
+	 *                  ...
+	 *                  U_c = PRF (P, U_{c-1}) .
+	 *
+	 *        Here, INT (i) is a four-octet encoding of the integer i, most
+	 *        significant octet first.
+	 *
+	 *     4. Concatenate the blocks and extract the first dkLen octets to
+	 *        produce a derived key DK:
+	 *
+	 *                  DK = T_1 || T_2 ||  ...  || T_l<0..r-1>
+	 *
+	 *     5. Output the derived key DK.
+	 *
+	 *  Note. The construction of the function F follows a "belt-and-
+	 *  suspenders" approach. The iterates U_i are computed recursively to
+	 *  remove a degree of parallelism from an opponent; they are exclusive-
+	 *  ored together to reduce concerns about the recursion degenerating
+	 *  into a small set of values.
+	 *
+	 */
+
+	/* If hash_block_size is provided, hash password in advance. */
+	if (hash_block_size > 0 && Plen > hash_block_size) {
+		if (hash_buf(P, Plen, P_hash, hLen, hash))
+			return -EINVAL;
+
+		if (crypt_hmac_init(&hmac, hash, P_hash, hLen))
+			return -EINVAL;
+		crypt_backend_memzero(P_hash, sizeof(P_hash));
+	} else {
+		if (crypt_hmac_init(&hmac, hash, P, Plen))
+			return -EINVAL;
+	}
+
+	for (i = 1; (unsigned int) i <= l; i++) {
+		memset(T, 0, hLen);
+
+		for (u = 1; u <= c ; u++) {
+			if (u == 1) {
+				memcpy(tmp, S, Slen);
+				tmp[Slen + 0] = (i & 0xff000000) >> 24;
+				tmp[Slen + 1] = (i & 0x00ff0000) >> 16;
+				tmp[Slen + 2] = (i & 0x0000ff00) >> 8;
+				tmp[Slen + 3] = (i & 0x000000ff) >> 0;
+
+				if (crypt_hmac_write(hmac, tmp, tmplen))
+					goto out;
+			} else {
+				if (crypt_hmac_write(hmac, U, hLen))
+					goto out;
+			}
+
+			if (crypt_hmac_final(hmac, U, hLen))
+				goto out;
+
+			for (k = 0; (unsigned int) k < hLen; k++)
+				T[k] ^= U[k];
+		}
+
+		memcpy(DK + (i - 1) * hLen, T, (unsigned int) i == l ? r : hLen);
+	}
+	rc = 0;
+out:
+	crypt_hmac_destroy(hmac);
+	crypt_backend_memzero(U, sizeof(U));
+	crypt_backend_memzero(T, sizeof(T));
+	crypt_backend_memzero(tmp, tmplen);
+
+	return rc;
+}