a122e02623
The previous PBKDF2 implementation used grub_crypto_hmac_buffer() which allocates and frees an HMAC handle on every call. This approach caused significant performance overhead slowing down the boot process considerably. This commit refactors the PBKDF2 code to use the new HMAC functions allowing the HMAC handle and its buffers to be allocated once and reused across multiple operations. This change significantly reduces disk unlocking time. In a QEMU/OVMF test environment this patch reduced the time to unlock a LUKS2 (*) partition from approximately 15 seconds to 4 seconds. (*) PBKDF2 SHA256 with 3454944 iterations. Signed-off-by: Gary Lin <glin@suse.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
/* 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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/* Imported from gnulib. */
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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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#include <grub/dl.h>
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GRUB_MOD_LICENSE ("GPLv2+");
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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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struct grub_crypto_hmac_handle *hnd = NULL;
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unsigned int hLen = md->mdlen;
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grub_uint8_t U[GRUB_CRYPTO_MAX_MDLEN];
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grub_uint8_t T[GRUB_CRYPTO_MAX_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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grub_uint8_t *tmp;
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grub_size_t tmplen = Slen + 4;
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if (md->mdlen > GRUB_CRYPTO_MAX_MDLEN || md->mdlen == 0)
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return GPG_ERR_INV_ARG;
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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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hnd = grub_crypto_hmac_init (md, P, Plen);
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if (hnd == NULL)
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{
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grub_free (tmp);
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return GPG_ERR_OUT_OF_MEMORY;
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}
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for (i = 1; i - 1 < l; i++)
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{
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grub_memset (T, 0, hLen);
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for (u = 0; u < c; u++)
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{
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if (u == 0)
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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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grub_crypto_hmac_write (hnd, tmp, tmplen);
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}
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else
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grub_crypto_hmac_write (hnd, U, hLen);
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grub_crypto_hmac_final (hnd, U);
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grub_crypto_hmac_reset (hnd);
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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_crypto_hmac_free (hnd);
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grub_free (tmp);
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return GPG_ERR_NO_ERROR;
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}
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