102 lines
2.8 KiB
C
102 lines
2.8 KiB
C
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/* gc-pbkdf2-sha1.c --- Password-Based Key Derivation Function a'la PKCS#5
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Copyright (C) 2002, 2003, 2004, 2005, 2006, 2009 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Written by Simon Josefsson. */
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#include <grub/crypto.h>
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#include <grub/mm.h>
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#include <grub/misc.h>
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/* Implement PKCS#5 PBKDF2 as per RFC 2898. The PRF to use is HMAC variant
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of digest supplied by MD. Inputs are the password P of length PLEN,
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the salt S of length SLEN, the iteration counter C (> 0), and the
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desired derived output length DKLEN. Output buffer is DK which
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must have room for at least DKLEN octets. The output buffer will
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be filled with the derived data. */
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gcry_err_code_t
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grub_crypto_pbkdf2 (const struct gcry_md_spec *md,
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const grub_uint8_t *P, grub_size_t Plen,
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const grub_uint8_t *S, grub_size_t Slen,
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unsigned int c,
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grub_uint8_t *DK, grub_size_t dkLen)
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{
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unsigned int hLen = md->mdlen;
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grub_uint8_t U[md->mdlen];
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grub_uint8_t T[md->mdlen];
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unsigned int u;
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unsigned int l;
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unsigned int r;
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unsigned int i;
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unsigned int k;
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gcry_err_code_t rc;
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grub_uint8_t *tmp;
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grub_size_t tmplen = Slen + 4;
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if (c == 0)
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return GPG_ERR_INV_ARG;
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if (dkLen == 0)
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return GPG_ERR_INV_ARG;
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if (dkLen > 4294967295U)
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return GPG_ERR_INV_ARG;
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l = ((dkLen - 1) / hLen) + 1;
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r = dkLen - (l - 1) * hLen;
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tmp = grub_malloc (tmplen);
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if (tmp == NULL)
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return GPG_ERR_OUT_OF_MEMORY;
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grub_memcpy (tmp, S, Slen);
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for (i = 1; i <= l; i++)
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{
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grub_memset (T, 0, hLen);
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for (u = 1; u <= c; u++)
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{
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if (u == 1)
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{
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tmp[Slen + 0] = (i & 0xff000000) >> 24;
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tmp[Slen + 1] = (i & 0x00ff0000) >> 16;
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tmp[Slen + 2] = (i & 0x0000ff00) >> 8;
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tmp[Slen + 3] = (i & 0x000000ff) >> 0;
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rc = grub_crypto_hmac_buffer (md, P, Plen, tmp, tmplen, U);
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}
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else
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rc = grub_crypto_hmac_buffer (md, P, Plen, U, hLen, U);
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if (rc != GPG_ERR_NO_ERROR)
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{
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grub_free (tmp);
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return rc;
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}
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for (k = 0; k < hLen; k++)
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T[k] ^= U[k];
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}
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grub_memcpy (DK + (i - 1) * hLen, T, i == l ? r : hLen);
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}
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grub_free (tmp);
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return GPG_ERR_NO_ERROR;
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}
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