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/* random-drbg.c - Deterministic Random Bits Generator
* Copyright 2014 Stephan Mueller <smueller@chronox.de>
*
* DRBG: Deterministic Random Bits Generator
* Based on NIST Recommended DRBG from NIST SP800-90A with the following
* properties:
* * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
* * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
* * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
* * with and without prediction resistance
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* LGPLv2+, in which case the provisions of the LGPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the LGPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*
* gcry_control GCRYCTL_DRBG_REINIT
* ================================
* This control request re-initializes the DRBG completely, i.e. the entire
* state of the DRBG is zeroized (with two exceptions listed in
* GCRYCTL_DRBG_SET_ENTROPY).
*
* The control request takes the following values which influences how
* the DRBG is re-initialized:
*
* - const char *flagstr
*
* This variable specifies the DRBG type to be used for the next
* initialization. If set to NULL, the previous DRBG type is
* used for the initialization. If not NULL a space separated
* list of tokens with associated flag values is expected which
* are ORed to form the mandatory flags of the requested DRBG
* strength and cipher type. Optionally, the prediction
* resistance flag can be ORed into the flags variable.
*
* | String token | Flag value |
* |--------------+------------------------|
* | aes | DRBG_CTRAES |
* | serpent | DRBG_CTRSERPENT |
* | twofish | DRBG_CTRTWOFISH |
* | sha1 | DRBG_HASHSHA1 |
* | sha256 | DRBG_HASHSHA256 |
* | sha512 | DRBG_HASHSHA512 |
* | hmac | DRBG_HMAC |
* | sym128 | DRBG_SYM128 |
* | sym192 | DRBG_SYM192 |
* | sym256 | DRBG_SYM256 |
* | pr | DRBG_PREDICTION_RESIST |
*
* For example:
*
* - CTR-DRBG with AES-128 without prediction resistance:
* "aes sym128"
* - HMAC-DRBG with SHA-512 with prediction resistance:
* "hmac sha512 pr"
*
* - gcry_buffer_t *pers
*
* NULL terminated array with personalization strings to be used
* for initialization.
*
* - int npers
*
* Size of PERS.
*
* - void *guard
*
* A value of NULL must be passed for this.
*
* The variable of flags is independent from the pers/perslen variables. If
* flags is set to 0 and perslen is set to 0, the current DRBG type is
* completely reset without using a personalization string.
*
* DRBG Usage
* ==========
* The SP 800-90A DRBG allows the user to specify a personalization string
* for initialization as well as an additional information string for each
* random number request. The following code fragments show how a caller
* uses the API to use the full functionality of the DRBG.
*
* Usage without any additional data
* ---------------------------------
* gcry_randomize(outbuf, OUTLEN, GCRY_STRONG_RANDOM);
*
*
* Usage with personalization string during initialization
* -------------------------------------------------------
* drbg_string_t pers;
* char personalization[11] = "some-string";
*
* drbg_string_fill(&pers, personalization, strlen(personalization));
* // The reset completely re-initializes the DRBG with the provided
* // personalization string without changing the DRBG type
* ret = gcry_control(GCRYCTL_DRBG_REINIT, 0, &pers);
* gcry_randomize(outbuf, OUTLEN, GCRY_STRONG_RANDOM);
*
*
* Usage with additional information string during random number request
* ---------------------------------------------------------------------
* drbg_string_t addtl;
* char addtl_string[11] = "some-string";
*
* drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
* // The following call is a wrapper to gcry_randomize() and returns
* // the same error codes.
* gcry_randomize_drbg(outbuf, OUTLEN, GCRY_STRONG_RANDOM, &addtl);
*
*
* Usage with personalization and additional information strings
* -------------------------------------------------------------
* Just mix both scenarios above.
*
*
* Switch the DRBG type to some other type
* ---------------------------------------
* // Switch to CTR DRBG AES-128 without prediction resistance
* ret = gcry_control(GCRYCTL_DRBG_REINIT, DRBG_NOPR_CTRAES128, NULL);
* gcry_randomize(outbuf, OUTLEN, GCRY_STRONG_RANDOM);
*/
#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <config.h>
#include "g10lib.h"
#include "random.h"
#include "rand-internal.h"
#include "../cipher/bufhelp.h"
/******************************************************************
* Constants
******************************************************************/
/*
* DRBG flags bitmasks
*
* 31 (B) 28 19 (A) 0
* +-+-+-+--------+---+-----------+-----+
* |~|~|u|~~~~~~~~| 3 | 2 | 1 |
* +-+-+-+--------+- -+-----------+-----+
* ctl flg| |drbg use selection flags
*
*/
/* Internal state control flags (B) */
#define DRBG_PREDICTION_RESIST ((u32)1<<28)
/* CTR type modifiers (A.1)*/
#define DRBG_CTRAES ((u32)1<<0)
#define DRBG_CTRSERPENT ((u32)1<<1)
#define DRBG_CTRTWOFISH ((u32)1<<2)
#define DRBG_CTR_MASK (DRBG_CTRAES | DRBG_CTRSERPENT \
| DRBG_CTRTWOFISH)
/* HASH type modifiers (A.2)*/
#define DRBG_HASHSHA1 ((u32)1<<4)
#define DRBG_HASHSHA224 ((u32)1<<5)
#define DRBG_HASHSHA256 ((u32)1<<6)
#define DRBG_HASHSHA384 ((u32)1<<7)
#define DRBG_HASHSHA512 ((u32)1<<8)
#define DRBG_HASH_MASK (DRBG_HASHSHA1 | DRBG_HASHSHA224 \
| DRBG_HASHSHA256 | DRBG_HASHSHA384 \
| DRBG_HASHSHA512)
/* type modifiers (A.3)*/
#define DRBG_HMAC ((u32)1<<12)
#define DRBG_SYM128 ((u32)1<<13)
#define DRBG_SYM192 ((u32)1<<14)
#define DRBG_SYM256 ((u32)1<<15)
#define DRBG_TYPE_MASK (DRBG_HMAC | DRBG_SYM128 | DRBG_SYM192 \
| DRBG_SYM256)
#define DRBG_CIPHER_MASK (DRBG_CTR_MASK | DRBG_HASH_MASK \
| DRBG_TYPE_MASK)
#define DRBG_PR_CTRAES128 (DRBG_PREDICTION_RESIST | DRBG_CTRAES | DRBG_SYM128)
#define DRBG_PR_CTRAES192 (DRBG_PREDICTION_RESIST | DRBG_CTRAES | DRBG_SYM192)
#define DRBG_PR_CTRAES256 (DRBG_PREDICTION_RESIST | DRBG_CTRAES | DRBG_SYM256)
#define DRBG_NOPR_CTRAES128 (DRBG_CTRAES | DRBG_SYM128)
#define DRBG_NOPR_CTRAES192 (DRBG_CTRAES | DRBG_SYM192)
#define DRBG_NOPR_CTRAES256 (DRBG_CTRAES | DRBG_SYM256)
#define DRBG_PR_HASHSHA1 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA1)
#define DRBG_PR_HASHSHA256 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA256)
#define DRBG_PR_HASHSHA384 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA384)
#define DRBG_PR_HASHSHA512 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA512)
#define DRBG_NOPR_HASHSHA1 (DRBG_HASHSHA1)
#define DRBG_NOPR_HASHSHA256 (DRBG_HASHSHA256)
#define DRBG_NOPR_HASHSHA384 (DRBG_HASHSHA384)
#define DRBG_NOPR_HASHSHA512 (DRBG_HASHSHA512)
#define DRBG_PR_HMACSHA1 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA1 \
| DRBG_HMAC)
#define DRBG_PR_HMACSHA256 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA256 \
| DRBG_HMAC)
#define DRBG_PR_HMACSHA384 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA384 \
| DRBG_HMAC)
#define DRBG_PR_HMACSHA512 (DRBG_PREDICTION_RESIST | DRBG_HASHSHA512 \
| DRBG_HMAC)
#define DRBG_NOPR_HMACSHA1 (DRBG_HASHSHA1 | DRBG_HMAC)
#define DRBG_NOPR_HMACSHA256 (DRBG_HASHSHA256 | DRBG_HMAC)
#define DRBG_NOPR_HMACSHA384 (DRBG_HASHSHA384 | DRBG_HMAC)
#define DRBG_NOPR_HMACSHA512 (DRBG_HASHSHA512 | DRBG_HMAC)
/* The default DRGB type. */
#define DRBG_DEFAULT_TYPE DRBG_NOPR_HMACSHA256
/******************************************************************
* Common data structures
******************************************************************/
/*
* SP800-90A requires the concatenation of different data. To avoid copying
* buffers around or allocate additional memory, the following data structure
* is used to point to the original memory with its size. In addition, it
* is used to build a linked list. The linked list defines the concatenation
* of individual buffers. The order of memory block referenced in that
* linked list determines the order of concatenation.
*/
struct drbg_string_s
{
const unsigned char *buf;
size_t len;
struct drbg_string_s *next;
};
typedef struct drbg_string_s drbg_string_t;
/* DRBG input data structure for DRBG generate with additional
* information string. */
struct drbg_gen_s
{
unsigned char *outbuf; /* output buffer for random numbers */
unsigned int outlen; /* size of output buffer */
drbg_string_t *addtl; /* input buffer for
* additional information string */
};
typedef struct drbg_gen_s drbg_gen_t;
/* Forward declaration of the state object pointer. */
struct drbg_state_s;
typedef struct drbg_state_s *drbg_state_t;
struct drbg_core_s
{
u32 flags; /* flags for the cipher */
ushort statelen; /* maximum state length */
ushort blocklen_bytes; /* block size of output in bytes */
int backend_cipher; /* libgcrypt backend cipher */
};
struct drbg_state_ops_s
{
gpg_err_code_t (*update) (drbg_state_t drbg,
drbg_string_t *seed, int reseed);
gpg_err_code_t (*generate) (drbg_state_t drbg,
unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl);
gpg_err_code_t (*crypto_init) (drbg_state_t drbg);
void (*crypto_fini) (drbg_state_t drbg);
};
struct drbg_test_data_s
{
drbg_string_t *testentropy; /* TEST PARAMETER: test entropy */
int fail_seed_source:1; /* If set, the seed function will
* return an error. */
};
/* This state object keeps the state of an DRBG instance. */
struct drbg_state_s
{
unsigned char *V; /* internal state 10.1.1.1 1a) */
unsigned char *C; /* hash: static value 10.1.1.1 1b)
* hmac / ctr: key */
size_t reseed_ctr; /* Number of RNG requests since last reseed --
* 10.1.1.1 1c) */
unsigned char *scratchpad; /* some memory the DRBG can use for its
* operation -- allocated during init */
void *priv_data; /* Cipher handle */
gcry_cipher_hd_t ctr_handle; /* CTR mode cipher handle */
#define DRBG_CTR_NULL_LEN 128
unsigned char *ctr_null; /* CTR mode zero buffer */
int seeded:1; /* DRBG fully seeded? */
int pr:1; /* Prediction resistance enabled? */
/* Taken from libgcrypt ANSI X9.31 DRNG: We need to keep track of the
* process which did the initialization so that we can detect a fork.
* The volatile modifier is required so that the compiler does not
* optimize it away in case the getpid function is badly attributed. */
pid_t seed_init_pid;
const struct drbg_state_ops_s *d_ops;
const struct drbg_core_s *core;
struct drbg_test_data_s *test_data;
};
enum drbg_prefixes
{
DRBG_PREFIX0 = 0x00,
DRBG_PREFIX1,
DRBG_PREFIX2,
DRBG_PREFIX3
};
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
/***************************************************************
* Global variables
***************************************************************/
/* Global state variable holding the current instance of the DRBG. */
static drbg_state_t drbg_state;
/* This is the lock variable we use to serialize access to this RNG. */
GPGRT_LOCK_DEFINE(drbg_lock_var);
/***************************************************************
* Backend cipher definitions available to DRBG
***************************************************************/
static const struct drbg_core_s drbg_cores[] = {
/* Hash DRBGs */
{DRBG_HASHSHA1, 55, 20, GCRY_MD_SHA1},
{DRBG_HASHSHA256, 55, 32, GCRY_MD_SHA256},
{DRBG_HASHSHA384, 111, 48, GCRY_MD_SHA384},
{DRBG_HASHSHA512, 111, 64, GCRY_MD_SHA512},
/* HMAC DRBGs */
{DRBG_HASHSHA1 | DRBG_HMAC, 20, 20, GCRY_MD_SHA1},
{DRBG_HASHSHA256 | DRBG_HMAC, 32, 32, GCRY_MD_SHA256},
{DRBG_HASHSHA384 | DRBG_HMAC, 48, 48, GCRY_MD_SHA384},
{DRBG_HASHSHA512 | DRBG_HMAC, 64, 64, GCRY_MD_SHA512},
/* block ciphers */
{DRBG_CTRAES | DRBG_SYM128, 32, 16, GCRY_CIPHER_AES128},
{DRBG_CTRAES | DRBG_SYM192, 40, 16, GCRY_CIPHER_AES192},
{DRBG_CTRAES | DRBG_SYM256, 48, 16, GCRY_CIPHER_AES256}
};
static gpg_err_code_t drbg_hash_init (drbg_state_t drbg);
static gpg_err_code_t drbg_hmac_init (drbg_state_t drbg);
static gpg_err_code_t drbg_hmac_setkey (drbg_state_t drbg,
const unsigned char *key);
static void drbg_hash_fini (drbg_state_t drbg);
static byte *drbg_hash (drbg_state_t drbg, const drbg_string_t *buf);
static gpg_err_code_t drbg_sym_init (drbg_state_t drbg);
static void drbg_sym_fini (drbg_state_t drbg);
static gpg_err_code_t drbg_sym_setkey (drbg_state_t drbg,
const unsigned char *key);
static gpg_err_code_t drbg_sym (drbg_state_t drbg, unsigned char *outval,
const drbg_string_t *buf);
static gpg_err_code_t drbg_sym_ctr (drbg_state_t drbg,
const unsigned char *inbuf, unsigned int inbuflen,
unsigned char *outbuf, unsigned int outbuflen);
/******************************************************************
******************************************************************
******************************************************************
* Generic DRBG code
******************************************************************
******************************************************************
******************************************************************/
/******************************************************************
* Generic helper functions
******************************************************************/
#if 0
#define dbg(x) do { log_debug x; } while(0)
#else
#define dbg(x)
#endif
/*
* Parse a string of flags and store the flag values at R_FLAGS.
* Return 0 on success.
*/
static gpg_err_code_t
parse_flag_string (const char *string, u32 *r_flags)
{
struct {
const char *name;
u32 flag;
} table[] = {
{ "aes", DRBG_CTRAES },
{ "serpent", DRBG_CTRSERPENT },
{ "twofish", DRBG_CTRTWOFISH },
{ "sha1", DRBG_HASHSHA1 },
{ "sha256", DRBG_HASHSHA256 },
{ "sha512", DRBG_HASHSHA512 },
{ "hmac", DRBG_HMAC },
{ "sym128", DRBG_SYM128 },
{ "sym192", DRBG_SYM192 },
{ "sym256", DRBG_SYM256 },
{ "pr", DRBG_PREDICTION_RESIST }
};
*r_flags = 0;
if (string)
{
char **tl;
const char *s;
int i, j;
tl = _gcry_strtokenize (string, NULL);
if (!tl)
return gpg_err_code_from_syserror ();
for (i=0; (s=tl[i]); i++)
{
for (j=0; j < DIM (table); j++)
if (!strcmp (s, table[j].name))
{
*r_flags |= table[j].flag;
break;
}
if (!(j < DIM (table)))
{
xfree (tl);
return GPG_ERR_INV_FLAG;
}
}
xfree (tl);
}
return 0;
}
static inline void
drbg_string_fill (drbg_string_t *string,
const unsigned char *buf, size_t len)
{
string->buf = buf;
string->len = len;
string->next = NULL;
}
static inline ushort
drbg_statelen (drbg_state_t drbg)
{
if (drbg && drbg->core)
return drbg->core->statelen;
return 0;
}
static inline ushort
drbg_blocklen (drbg_state_t drbg)
{
if (drbg && drbg->core)
return drbg->core->blocklen_bytes;
return 0;
}
static inline ushort
drbg_keylen (drbg_state_t drbg)
{
if (drbg && drbg->core)
return (drbg->core->statelen - drbg->core->blocklen_bytes);
return 0;
}
static inline size_t
drbg_max_request_bytes (void)
{
/* SP800-90A requires the limit 2**19 bits, but we return bytes */
return (1 << 16);
}
static inline size_t
drbg_max_addtl (void)
{
/* SP800-90A requires 2**35 bytes additional info str / pers str */
#ifdef __LP64__
return (1UL << 35);
#else
/*
* SP800-90A allows smaller maximum numbers to be returned -- we
* return SIZE_MAX - 1 to allow the verification of the enforcement
* of this value in drbg_healthcheck_sanity.
*/
return (SIZE_MAX - 1);
#endif
}
static inline size_t
drbg_max_requests (void)
{
/* SP800-90A requires 2**48 maximum requests before reseeding */
#ifdef __LP64__
return (1UL << 48);
#else
return SIZE_MAX;
#endif
}
/*
* Return strength of DRBG according to SP800-90A section 8.4
*
* flags: DRBG flags reference
*
* Return: normalized strength value or 32 as a default to counter
* programming errors
*/
static inline unsigned short
drbg_sec_strength (u32 flags)
{
if ((flags & DRBG_HASHSHA1) || (flags & DRBG_SYM128))
return 16;
else if (flags & DRBG_SYM192)
return 24;
else if ((flags & DRBG_SYM256) || (flags & DRBG_HASHSHA256) ||
(flags & DRBG_HASHSHA384) || (flags & DRBG_HASHSHA512))
return 32;
else
return 32;
}
static void
drbg_add_buf (unsigned char *dst, size_t dstlen,
unsigned char *add, size_t addlen)
{
/* implied: dstlen > addlen */
unsigned char *dstptr, *addptr;
unsigned int remainder = 0;
size_t len = addlen;
dstptr = dst + (dstlen - 1);
addptr = add + (addlen - 1);
while (len)
{
remainder += *dstptr + *addptr;
*dstptr = remainder & 0xff;
remainder >>= 8;
len--;
dstptr--;
addptr--;
}
len = dstlen - addlen;
while (len && remainder > 0)
{
remainder = *dstptr + 1;
*dstptr = remainder & 0xff;
remainder >>= 8;
len--;
dstptr--;
}
}
/* Helper variables for read_cb().
*
* The _gcry_rnd*_gather_random interface does not allow to provide a
* data pointer. Thus we need to use a global variable for
* communication. However, the then required locking is anyway a good
* idea because it does not make sense to have several readers of (say
* /dev/random). It is easier to serve them one after the other.
*/
static unsigned char *read_cb_buffer; /* The buffer. */
static size_t read_cb_size; /* Size of the buffer. */
static size_t read_cb_len; /* Used length. */
/* Callback for generating seed from kernel device. */
static void
drbg_read_cb (const void *buffer, size_t length,
enum random_origins origin)
{
const unsigned char *p = buffer;
(void) origin;
gcry_assert (read_cb_buffer);
/* Note that we need to protect against gatherers returning more
* than the requested bytes (e.g. rndw32). */
while (length-- && read_cb_len < read_cb_size)
read_cb_buffer[read_cb_len++] = *p++;
}
static inline int
drbg_get_entropy (drbg_state_t drbg, unsigned char *buffer,
size_t len)
{
int rc = 0;
/* Perform testing as defined in 11.3.2 */
if (drbg->test_data && drbg->test_data->fail_seed_source)
return -1;
read_cb_buffer = buffer;
read_cb_size = len;
read_cb_len = 0;
#if USE_RNDLINUX
rc = _gcry_rndlinux_gather_random (drbg_read_cb, 0, len,
GCRY_VERY_STRONG_RANDOM);
#elif USE_RNDUNIX
rc = _gcry_rndunix_gather_random (drbg_read_cb, 0, len,
GCRY_VERY_STRONG_RANDOM);
#elif USE_RNDW32
do
{
rc = _gcry_rndw32_gather_random (drbg_read_cb, 0, len,
GCRY_VERY_STRONG_RANDOM);
}
while (rc >= 0 && read_cb_len < read_cb_size);
#else
rc = -1;
#endif
return rc;
}
/******************************************************************
* CTR DRBG callback functions
******************************************************************/
/* BCC function for CTR DRBG as defined in 10.4.3 */
static gpg_err_code_t
drbg_ctr_bcc (drbg_state_t drbg,
unsigned char *out, const unsigned char *key,
drbg_string_t *in)
{
gpg_err_code_t ret = GPG_ERR_GENERAL;
drbg_string_t *curr = in;
size_t inpos = curr->len;
const unsigned char *pos = curr->buf;
drbg_string_t data;
drbg_string_fill (&data, out, drbg_blocklen (drbg));
/* 10.4.3 step 1 */
memset (out, 0, drbg_blocklen (drbg));
ret = drbg_sym_setkey(drbg, key);
if (ret)
return ret;
/* 10.4.3 step 2 / 4 */
while (inpos)
{
short cnt = 0;
/* 10.4.3 step 4.1 */
for (cnt = 0; cnt < drbg_blocklen (drbg); cnt++)
{
out[cnt] ^= *pos;
pos++;
inpos--;
/* the following branch implements the linked list
* iteration. If we are at the end of the current data
* set, we have to start using the next data set if
* available -- the inpos value always points to the
* current byte and will be zero if we have processed
* the last byte of the last linked list member */
if (0 == inpos)
{
curr = curr->next;
if (NULL != curr)
{
pos = curr->buf;
inpos = curr->len;
}
else
{
inpos = 0;
break;
}
}
}
/* 10.4.3 step 4.2 */
ret = drbg_sym (drbg, out, &data);
if (ret)
return ret;
/* 10.4.3 step 2 */
}
return 0;
}
/*
* scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
* (and drbg_ctr_bcc, but this function does not need any temporary buffers),
* the scratchpad is used as follows:
* drbg_ctr_update:
* temp
* start: drbg->scratchpad
* length: drbg_statelen(drbg) + drbg_blocklen(drbg)
* note: the cipher writing into this variable works
* blocklen-wise. Now, when the statelen is not a multiple
* of blocklen, the generateion loop below "spills over"
* by at most blocklen. Thus, we need to give sufficient
* memory.
* df_data
* start: drbg->scratchpad +
* drbg_statelen(drbg) +
* drbg_blocklen(drbg)
* length: drbg_statelen(drbg)
*
* drbg_ctr_df:
* pad
* start: df_data + drbg_statelen(drbg)
* length: drbg_blocklen(drbg)
* iv
* start: pad + drbg_blocklen(drbg)
* length: drbg_blocklen(drbg)
* temp
* start: iv + drbg_blocklen(drbg)
* length: drbg_satelen(drbg) + drbg_blocklen(drbg)
* note: temp is the buffer that the BCC function operates
* on. BCC operates blockwise. drbg_statelen(drbg)
* is sufficient when the DRBG state length is a multiple
* of the block size. For AES192 (and maybe other ciphers)
* this is not correct and the length for temp is
* insufficient (yes, that also means for such ciphers,
* the final output of all BCC rounds are truncated).
* Therefore, add drbg_blocklen(drbg) to cover all
* possibilities.
*/
/* Derivation Function for CTR DRBG as defined in 10.4.2 */
static gpg_err_code_t
drbg_ctr_df (drbg_state_t drbg, unsigned char *df_data,
size_t bytes_to_return, drbg_string_t *addtl)
{
gpg_err_code_t ret = GPG_ERR_GENERAL;
unsigned char L_N[8];
/* S3 is input */
drbg_string_t S1, S2, S4, cipherin;
drbg_string_t *tempstr = addtl;
unsigned char *pad = df_data + drbg_statelen (drbg);
unsigned char *iv = pad + drbg_blocklen (drbg);
unsigned char *temp = iv + drbg_blocklen (drbg);
size_t padlen = 0;
unsigned int templen = 0;
/* 10.4.2 step 7 */
unsigned int i = 0;
/* 10.4.2 step 8 */
const unsigned char *K = (unsigned char *)
"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
unsigned char *X;
size_t generated_len = 0;
size_t inputlen = 0;
memset (pad, 0, drbg_blocklen (drbg));
memset (iv, 0, drbg_blocklen (drbg));
memset (temp, 0, drbg_statelen (drbg));
/* 10.4.2 step 1 is implicit as we work byte-wise */
/* 10.4.2 step 2 */
if ((512 / 8) < bytes_to_return)
return GPG_ERR_INV_ARG;
/* 10.4.2 step 2 -- calculate the entire length of all input data */
for (; NULL != tempstr; tempstr = tempstr->next)
inputlen += tempstr->len;
buf_put_be32 (&L_N[0], inputlen);
/* 10.4.2 step 3 */
buf_put_be32 (&L_N[4], bytes_to_return);
/* 10.4.2 step 5: length is size of L_N, input_string, one byte, padding */
padlen = (inputlen + sizeof (L_N) + 1) % (drbg_blocklen (drbg));
/* wrap the padlen appropriately */
if (padlen)
padlen = drbg_blocklen (drbg) - padlen;
/* pad / padlen contains the 0x80 byte and the following zero bytes, so
* add one for byte for 0x80 */
padlen++;
pad[0] = 0x80;
/* 10.4.2 step 4 -- first fill the linked list and then order it */
drbg_string_fill (&S1, iv, drbg_blocklen (drbg));
drbg_string_fill (&S2, L_N, sizeof (L_N));
drbg_string_fill (&S4, pad, padlen);
S1.next = &S2;
S2.next = addtl;
/* Splice in addtl between S2 and S4 -- we place S4 at the end of the
* input data chain. As this code is only triggered when addtl is not
* NULL, no NULL checks are necessary.*/
tempstr = addtl;
while (tempstr->next)
tempstr = tempstr->next;
tempstr->next = &S4;
/* 10.4.2 step 9 */
while (templen < (drbg_keylen (drbg) + (drbg_blocklen (drbg))))
{
/* 10.4.2 step 9.1 - the padding is implicit as the buffer
* holds zeros after allocation -- even the increment of i
* is irrelevant as the increment remains within length of i */
buf_put_be32 (iv, i);
/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
ret = drbg_ctr_bcc (drbg, temp + templen, K, &S1);
if (ret)
goto out;
/* 10.4.2 step 9.3 */
i++;
templen += drbg_blocklen (drbg);
}
/* 10.4.2 step 11 */
/* implicit key len with seedlen - blocklen according to table 3 */
X = temp + (drbg_keylen (drbg));
drbg_string_fill (&cipherin, X, drbg_blocklen (drbg));
/* 10.4.2 step 12: overwriting of outval */
/* 10.4.2 step 13 */
ret = drbg_sym_setkey(drbg, temp);
if (ret)
goto out;
while (generated_len < bytes_to_return)
{
short blocklen = 0;
/* 10.4.2 step 13.1 */
/* the truncation of the key length is implicit as the key
* is only drbg_blocklen in size -- check for the implementation
* of the cipher function callback */
ret = drbg_sym (drbg, X, &cipherin);
if (ret)
goto out;
blocklen = (drbg_blocklen (drbg) < (bytes_to_return - generated_len)) ?
drbg_blocklen (drbg) : (bytes_to_return - generated_len);
/* 10.4.2 step 13.2 and 14 */
memcpy (df_data + generated_len, X, blocklen);
generated_len += blocklen;
}
ret = 0;
out:
memset (iv, 0, drbg_blocklen (drbg));
memset (temp, 0, drbg_statelen (drbg));
memset (pad, 0, drbg_blocklen (drbg));
return ret;
}
/*
* Update function of CTR DRBG as defined in 10.2.1.2
*
* The reseed variable has an enhanced meaning compared to the update
* functions of the other DRBGs as follows:
* 0 => initial seed from initialization
* 1 => reseed via drbg_seed
* 2 => first invocation from drbg_ctr_update when addtl is present. In
* this case, the df_data scratchpad is not deleted so that it is
* available for another calls to prevent calling the DF function
* again.
* 3 => second invocation from drbg_ctr_update. When the update function
* was called with addtl, the df_data memory already contains the
* DFed addtl information and we do not need to call DF again.
*/
static gpg_err_code_t
drbg_ctr_update (drbg_state_t drbg, drbg_string_t *addtl, int reseed)
{
gpg_err_code_t ret = GPG_ERR_GENERAL;
/* 10.2.1.2 step 1 */
unsigned char *temp = drbg->scratchpad;
unsigned char *df_data = drbg->scratchpad +
drbg_statelen (drbg) + drbg_blocklen (drbg);
unsigned char prefix = DRBG_PREFIX1;
memset (temp, 0, drbg_statelen (drbg) + drbg_blocklen (drbg));
if (3 > reseed)
memset (df_data, 0, drbg_statelen (drbg));
if (!reseed)
{
/*
* The DRBG uses the CTR mode of the underlying AES cipher. The
* CTR mode increments the counter value after the AES operation
* but SP800-90A requires that the counter is incremented before
* the AES operation. Hence, we increment it at the time we set
* it by one.
*/
drbg_add_buf (drbg->V, drbg_blocklen (drbg), &prefix, 1);
ret = _gcry_cipher_setkey (drbg->ctr_handle, drbg->C, drbg_keylen (drbg));
if (ret)
goto out;
}
/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
if (addtl && 0 < addtl->len)
{
ret =
drbg_ctr_df (drbg, df_data, drbg_statelen (drbg), addtl);
if (ret)
goto out;
}
ret = drbg_sym_ctr (drbg, df_data, drbg_statelen(drbg),
temp, drbg_statelen(drbg));
if (ret)
goto out;
/* 10.2.1.2 step 5 */
ret = _gcry_cipher_setkey (drbg->ctr_handle, temp, drbg_keylen (drbg));
if (ret)
goto out;
/* 10.2.1.2 step 6 */
memcpy (drbg->V, temp + drbg_keylen (drbg), drbg_blocklen (drbg));
/* See above: increment counter by one to compensate timing of CTR op */
drbg_add_buf (drbg->V, drbg_blocklen (drbg), &prefix, 1);
ret = 0;
out:
memset (temp, 0, drbg_statelen (drbg) + drbg_blocklen (drbg));
if (2 != reseed)
memset (df_data, 0, drbg_statelen (drbg));
return ret;
}
/*
* scratchpad use: drbg_ctr_update is called independently from
* drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
*/
/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
static gpg_err_code_t
drbg_ctr_generate (drbg_state_t drbg,
unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl)
{
gpg_err_code_t ret = 0;
memset (drbg->scratchpad, 0, drbg_blocklen (drbg));
/* 10.2.1.5.2 step 2 */
if (addtl && 0 < addtl->len)
{
addtl->next = NULL;
ret = drbg_ctr_update (drbg, addtl, 2);
if (ret)
return ret;
}
/* 10.2.1.5.2 step 4.1 */
ret = drbg_sym_ctr (drbg, drbg->ctr_null, DRBG_CTR_NULL_LEN, buf, buflen);
if (ret)
goto out;
/* 10.2.1.5.2 step 6 */
if (addtl)
addtl->next = NULL;
ret = drbg_ctr_update (drbg, addtl, 3);
out:
return ret;
}
static struct drbg_state_ops_s drbg_ctr_ops = {
drbg_ctr_update,
drbg_ctr_generate,
drbg_sym_init,
drbg_sym_fini,
};
/******************************************************************
* HMAC DRBG callback functions
******************************************************************/
static gpg_err_code_t
drbg_hmac_update (drbg_state_t drbg, drbg_string_t *seed, int reseed)
{
gpg_err_code_t ret = GPG_ERR_GENERAL;
int i = 0;
drbg_string_t seed1, seed2, cipherin;
if (!reseed)
{
/* 10.1.2.3 step 2 already implicitly covered with
* the initial memset(0) of drbg->C */
memset (drbg->V, 1, drbg_statelen (drbg));
ret = drbg_hmac_setkey (drbg, drbg->C);
if (ret)
return ret;
}
/* build linked list which implements the concatenation and fill
* first part*/
drbg_string_fill (&seed1, drbg->V, drbg_statelen (drbg));
/* buffer will be filled in for loop below with one byte */
drbg_string_fill (&seed2, NULL, 1);
seed1.next = &seed2;
/* seed may be NULL */
seed2.next = seed;
drbg_string_fill (&cipherin, drbg->V, drbg_statelen (drbg));
/* we execute two rounds of V/K massaging */
for (i = 2; 0 < i; i--)
{
byte *retval;
/* first round uses 0x0, second 0x1 */
unsigned char prefix = DRBG_PREFIX0;
if (1 == i)
prefix = DRBG_PREFIX1;
/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
seed2.buf = &prefix;
retval = drbg_hash (drbg, &seed1);
ret = drbg_hmac_setkey (drbg, retval);
if (ret)
return ret;
/* 10.1.2.2 step 2 and 5 -- HMAC for V */
retval = drbg_hash (drbg, &cipherin);
memcpy(drbg->V, retval, drbg_blocklen (drbg));
/* 10.1.2.2 step 3 */
if (!seed || 0 == seed->len)
return ret;
}
return 0;
}
/* generate function of HMAC DRBG as defined in 10.1.2.5 */
static gpg_err_code_t
drbg_hmac_generate (drbg_state_t drbg, unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl)
{
gpg_err_code_t ret = 0;
unsigned int len = 0;
drbg_string_t data;
/* 10.1.2.5 step 2 */
if (addtl && 0 < addtl->len)
{
addtl->next = NULL;
ret = drbg_hmac_update (drbg, addtl, 1);
if (ret)
return ret;
}
drbg_string_fill (&data, drbg->V, drbg_statelen (drbg));
while (len < buflen)
{
unsigned int outlen = 0;
/* 10.1.2.5 step 4.1 */
byte *retval = drbg_hash (drbg, &data);
memcpy(drbg->V, retval, drbg_blocklen (drbg));
outlen = (drbg_blocklen (drbg) < (buflen - len)) ?
drbg_blocklen (drbg) : (buflen - len);
/* 10.1.2.5 step 4.2 */
memcpy (buf + len, drbg->V, outlen);
len += outlen;
}
/* 10.1.2.5 step 6 */
if (addtl)
addtl->next = NULL;
ret = drbg_hmac_update (drbg, addtl, 1);
return ret;
}
static struct drbg_state_ops_s drbg_hmac_ops = {
drbg_hmac_update,
drbg_hmac_generate,
drbg_hmac_init,
drbg_hash_fini,
};
/******************************************************************
* Hash DRBG callback functions
******************************************************************/
/*
* scratchpad usage: as drbg_hash_update and drbg_hash_df are used
* interlinked, the scratchpad is used as follows:
* drbg_hash_update
* start: drbg->scratchpad
* length: drbg_statelen(drbg)
* drbg_hash_df:
* start: drbg->scratchpad + drbg_statelen(drbg)
* length: drbg_blocklen(drbg)
*/
/* Derivation Function for Hash DRBG as defined in 10.4.1 */
static gpg_err_code_t
drbg_hash_df (drbg_state_t drbg,
unsigned char *outval, size_t outlen,
drbg_string_t *entropy)
{
size_t len = 0;
unsigned char input[5];
drbg_string_t data1;
/* 10.4.1 step 3 */
input[0] = 1;
buf_put_be32 (&input[1], (outlen * 8));
/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
drbg_string_fill (&data1, input, 5);
data1.next = entropy;
/* 10.4.1 step 4 */
while (len < outlen)
{
short blocklen = 0;
/* 10.4.1 step 4.1 */
byte *retval = drbg_hash (drbg, &data1);
/* 10.4.1 step 4.2 */
input[0]++;
blocklen = (drbg_blocklen (drbg) < (outlen - len)) ?
drbg_blocklen (drbg) : (outlen - len);
memcpy (outval + len, retval, blocklen);
len += blocklen;
}
return 0;
}
/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
static gpg_err_code_t
drbg_hash_update (drbg_state_t drbg, drbg_string_t *seed, int reseed)
{
gpg_err_code_t ret = 0;
drbg_string_t data1, data2;
unsigned char *V = drbg->scratchpad;
unsigned char prefix = DRBG_PREFIX1;
memset (drbg->scratchpad, 0, drbg_statelen (drbg));
if (!seed)
return GPG_ERR_INV_ARG;
if (reseed)
{
/* 10.1.1.3 step 1: string length is concatenation of
* 1 byte, V and seed (which is concatenated entropy/addtl
* input)
*/
memcpy (V, drbg->V, drbg_statelen (drbg));
drbg_string_fill (&data1, &prefix, 1);
drbg_string_fill (&data2, V, drbg_statelen (drbg));
data1.next = &data2;
data2.next = seed;
}
else
{
drbg_string_fill (&data1, seed->buf, seed->len);
data1.next = seed->next;
}
/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
ret = drbg_hash_df (drbg, drbg->V, drbg_statelen (drbg), &data1);
if (ret)
goto out;
/* 10.1.1.2 / 10.1.1.3 step 4 -- concatenation */
prefix = DRBG_PREFIX0;
drbg_string_fill (&data1, &prefix, 1);
drbg_string_fill (&data2, drbg->V, drbg_statelen (drbg));
data1.next = &data2;
/* 10.1.1.2 / 10.1.1.3 step 4 -- df operation */
ret = drbg_hash_df (drbg, drbg->C, drbg_statelen (drbg), &data1);
out:
memset (drbg->scratchpad, 0, drbg_statelen (drbg));
return ret;
}
/* Processing of additional information string for Hash DRBG. */
static gpg_err_code_t
drbg_hash_process_addtl (drbg_state_t drbg, drbg_string_t *addtl)
{
drbg_string_t data1, data2;
drbg_string_t *data3;
unsigned char prefix = DRBG_PREFIX2;
byte *retval;
/* 10.1.1.4 step 2 */
if (!addtl || 0 == addtl->len)
return 0;
/* 10.1.1.4 step 2a -- concatenation */
drbg_string_fill (&data1, &prefix, 1);
drbg_string_fill (&data2, drbg->V, drbg_statelen (drbg));
data3 = addtl;
data1.next = &data2;
data2.next = data3;
data3->next = NULL;
/* 10.1.1.4 step 2a -- cipher invocation */
retval = drbg_hash (drbg, &data1);
/* 10.1.1.4 step 2b */
drbg_add_buf (drbg->V, drbg_statelen (drbg), retval, drbg_blocklen (drbg));
return 0;
}
/*
* Hashgen defined in 10.1.1.4
*/
static gpg_err_code_t
drbg_hash_hashgen (drbg_state_t drbg, unsigned char *buf, unsigned int buflen)
{
unsigned int len = 0;
unsigned char *src = drbg->scratchpad;
drbg_string_t data;
unsigned char prefix = DRBG_PREFIX1;
/* 10.1.1.4 step hashgen 2 */
memcpy (src, drbg->V, drbg_statelen (drbg));
drbg_string_fill (&data, src, drbg_statelen (drbg));
while (len < buflen)
{
unsigned int outlen = 0;
/* 10.1.1.4 step hashgen 4.1 */
byte *retval = drbg_hash (drbg, &data);
outlen = (drbg_blocklen (drbg) < (buflen - len)) ?
drbg_blocklen (drbg) : (buflen - len);
/* 10.1.1.4 step hashgen 4.2 */
memcpy (buf + len, retval, outlen);
len += outlen;
/* 10.1.1.4 hashgen step 4.3 */
if (len < buflen)
drbg_add_buf (src, drbg_statelen (drbg), &prefix, 1);
}
memset (drbg->scratchpad, 0, drbg_statelen (drbg));
return 0;
}
/* Generate function for Hash DRBG as defined in 10.1.1.4 */
static gpg_err_code_t
drbg_hash_generate (drbg_state_t drbg, unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl)
{
gpg_err_code_t ret;
unsigned char prefix = DRBG_PREFIX3;
drbg_string_t data1, data2;
byte *retval;
union
{
unsigned char req[8];
u64 req_int;
} u;
/* 10.1.1.4 step 2 */
ret = drbg_hash_process_addtl (drbg, addtl);
if (ret)
return ret;
/* 10.1.1.4 step 3 -- invocation of the Hashgen function defined in
* 10.1.1.4 */
ret = drbg_hash_hashgen (drbg, buf, buflen);
if (ret)
return ret;
/* 10.1.1.4 step 4 */
drbg_string_fill (&data1, &prefix, 1);
drbg_string_fill (&data2, drbg->V, drbg_statelen (drbg));
data1.next = &data2;
/* this is the value H as documented in 10.1.1.4 */
retval = drbg_hash (drbg, &data1);
/* 10.1.1.4 step 5 */
drbg_add_buf (drbg->V, drbg_statelen (drbg), retval, drbg_blocklen (drbg));
drbg_add_buf (drbg->V, drbg_statelen (drbg), drbg->C, drbg_statelen (drbg));
u.req_int = be_bswap64 (drbg->reseed_ctr);
drbg_add_buf (drbg->V, drbg_statelen (drbg), u.req, sizeof (u.req));
return ret;
}
/*
* scratchpad usage: as update and generate are used isolated, both
* can use the scratchpad
*/
static struct drbg_state_ops_s drbg_hash_ops = {
drbg_hash_update,
drbg_hash_generate,
drbg_hash_init,
drbg_hash_fini,
};
/******************************************************************
* Functions common for DRBG implementations
******************************************************************/
/*
* Seeding or reseeding of the DRBG
*
* @drbg: DRBG state struct
* @pers: personalization / additional information buffer
* @reseed: 0 for initial seed process, 1 for reseeding
*
* return:
* 0 on success
* error value otherwise
*/
static gpg_err_code_t
drbg_seed (drbg_state_t drbg, drbg_string_t *pers, int reseed)
{
gpg_err_code_t ret = 0;
unsigned char *entropy = NULL;
size_t entropylen = 0;
drbg_string_t data1;
/* 9.1 / 9.2 / 9.3.1 step 3 */
if (pers && pers->len > (drbg_max_addtl ()))
{
dbg (("DRBG: personalization string too long %lu\n", pers->len));
return GPG_ERR_INV_ARG;
}
if (drbg->test_data && drbg->test_data->testentropy)
{
drbg_string_fill (&data1, drbg->test_data->testentropy->buf,
drbg->test_data->testentropy->len);
dbg (("DRBG: using test entropy\n"));
}
else
{
/* Gather entropy equal to the security strength of the DRBG.
* With a derivation function, a nonce is required in addition
* to the entropy. A nonce must be at least 1/2 of the security
* strength of the DRBG in size. Thus, entropy * nonce is 3/2
* of the strength. The consideration of a nonce is only
* applicable during initial seeding. */
entropylen = drbg_sec_strength (drbg->core->flags);
if (!entropylen)
return GPG_ERR_GENERAL;
if (0 == reseed)
/* make sure we round up strength/2 in
* case it is not divisible by 2 */
entropylen = ((entropylen + 1) / 2) * 3;
dbg (("DRBG: (re)seeding with %lu bytes of entropy\n", entropylen));
entropy = xcalloc_secure (1, entropylen);
if (!entropy)
return GPG_ERR_ENOMEM;
ret = drbg_get_entropy (drbg, entropy, entropylen);
if (ret)
goto out;
drbg_string_fill (&data1, entropy, entropylen);
}
/* concatenation of entropy with personalization str / addtl input)
* the variable pers is directly handed by the caller, check its
* contents whether it is appropriate */
if (pers && pers->buf && 0 < pers->len && NULL == pers->next)
{
data1.next = pers;
dbg (("DRBG: using personalization string\n"));
}
ret = drbg->d_ops->update (drbg, &data1, reseed);
dbg (("DRBG: state updated with seed\n"));
if (ret)
goto out;
drbg->seeded = 1;
/* 10.1.1.2 / 10.1.1.3 step 5 */
drbg->reseed_ctr = 1;
out:
xfree (entropy);
return ret;
}
/*************************************************************************
* Exported interfaces.
*************************************************************************/
/*
* DRBG generate function as required by SP800-90A - this function
* generates random numbers
*
* @drbg DRBG state handle
* @buf Buffer where to store the random numbers -- the buffer must already
* be pre-allocated by caller
* @buflen Length of output buffer - this value defines the number of random
* bytes pulled from DRBG
* @addtl Additional input that is mixed into state, may be NULL -- note
* the entropy is pulled by the DRBG internally unconditionally
* as defined in SP800-90A. The additional input is mixed into
* the state in addition to the pulled entropy.
*
* return: Generated number of bytes.
*/
static gpg_err_code_t
drbg_generate (drbg_state_t drbg,
unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl)
{
gpg_err_code_t ret = GPG_ERR_INV_ARG;
if (0 == buflen || !buf)
{
dbg (("DRBG: no buffer provided\n"));
return ret;
}
if (addtl && NULL == addtl->buf && 0 < addtl->len)
{
dbg (("DRBG: wrong format of additional information\n"));
return ret;
}
/* 9.3.1 step 2 */
if (buflen > (drbg_max_request_bytes ()))
{
dbg (("DRBG: requested random numbers too large %u\n", buflen));
return ret;
}
/* 9.3.1 step 3 is implicit with the chosen DRBG */
/* 9.3.1 step 4 */
if (addtl && addtl->len > (drbg_max_addtl ()))
{
dbg (("DRBG: additional information string too long %lu\n",
addtl->len));
return ret;
}
/* 9.3.1 step 5 is implicit with the chosen DRBG */
/* 9.3.1 step 6 and 9 supplemented by 9.3.2 step c -- the spec is a
* bit convoluted here, we make it simpler */
if ((drbg_max_requests ()) < drbg->reseed_ctr)
drbg->seeded = 0;
if (drbg->pr || !drbg->seeded)
{
dbg (("DRBG: reseeding before generation (prediction resistance: %s, state %s)\n", drbg->pr ? "true" : "false", drbg->seeded ? "seeded" : "unseeded"));
/* 9.3.1 steps 7.1 through 7.3 */
ret = drbg_seed (drbg, addtl, 1);
if (ret)
return ret;
/* 9.3.1 step 7.4 */
addtl = NULL;
}
if (addtl && addtl->buf)
{
dbg (("DRBG: using additional information string\n"));
}
/* 9.3.1 step 8 and 10 */
ret = drbg->d_ops->generate (drbg, buf, buflen, addtl);
/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
drbg->reseed_ctr++;
if (ret)
return ret;
/* 11.3.3 -- re-perform self tests after some generated random
* numbers, the chosen value after which self test is performed
* is arbitrary, but it should be reasonable */
/* Here we do not perform the self tests because of the following
* reasons: it is mathematically impossible that the initial self tests
* were successfully and the following are not. If the initial would
* pass and the following would not, the system integrity is violated.
* In this case, the entire system operation is questionable and it
* is unlikely that the integrity violation only affects to the
* correct operation of the DRBG.
*/
#if 0
if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096))
{
dbg (("DRBG: start to perform self test\n"));
ret = drbg_healthcheck ();
if (ret)
{
log_fatal (("DRBG: self test failed\n"));
return ret;
}
else
{
dbg (("DRBG: self test successful\n"));
}
}
#endif
return ret;
}
/*
* Wrapper around drbg_generate which can pull arbitrary long strings
* from the DRBG without hitting the maximum request limitation.
*
* Parameters: see drbg_generate
* Return codes: see drbg_generate -- if one drbg_generate request fails,
* the entire drbg_generate_long request fails
*/
static gpg_err_code_t
drbg_generate_long (drbg_state_t drbg,
unsigned char *buf, unsigned int buflen,
drbg_string_t *addtl)
{
gpg_err_code_t ret = 0;
unsigned int slice = 0;
unsigned char *buf_p = buf;
unsigned len = 0;
do
{
unsigned int chunk = 0;
slice = ((buflen - len) / drbg_max_request_bytes ());
chunk = slice ? drbg_max_request_bytes () : (buflen - len);
ret = drbg_generate (drbg, buf_p, chunk, addtl);
if (ret)
return ret;
buf_p += chunk;
len += chunk;
}
while (slice > 0 && (len < buflen));
return ret;
}
/*
* DRBG uninstantiate function as required by SP800-90A - this function
* frees all buffers and the DRBG handle
*
* @drbg DRBG state handle
*
* return
* 0 on success
*/
static gpg_err_code_t
drbg_uninstantiate (drbg_state_t drbg)
{
if (!drbg)
return GPG_ERR_INV_ARG;
drbg->d_ops->crypto_fini(drbg);
xfree (drbg->V);
drbg->V = NULL;
xfree (drbg->C);
drbg->C = NULL;
drbg->reseed_ctr = 0;
xfree (drbg->scratchpad);
drbg->scratchpad = NULL;
drbg->seeded = 0;
drbg->pr = 0;
drbg->seed_init_pid = 0;
return 0;
}
/*
* DRBG instantiation function as required by SP800-90A - this function
* sets up the DRBG handle, performs the initial seeding and all sanity
* checks required by SP800-90A
*
* @drbg memory of state -- if NULL, new memory is allocated
* @pers Personalization string that is mixed into state, may be NULL -- note
* the entropy is pulled by the DRBG internally unconditionally
* as defined in SP800-90A. The additional input is mixed into
* the state in addition to the pulled entropy.
* @coreref reference to core
* @flags Flags defining the requested DRBG type and cipher type. The flags
* are defined in drbg.h and may be XORed. Beware, if you XOR multiple
* cipher types together, the code picks the core on a first come first
* serve basis as it iterates through the available cipher cores and
* uses the one with the first match. The minimum required flags are:
* cipher type flag
*
* return
* 0 on success
* error value otherwise
*/
static gpg_err_code_t
drbg_instantiate (drbg_state_t drbg,
drbg_string_t *pers, int coreref, int pr)
{
gpg_err_code_t ret = GPG_ERR_ENOMEM;
unsigned int sb_size = 0;
if (!drbg)
return GPG_ERR_INV_ARG;
dbg (("DRBG: Initializing DRBG core %d with prediction resistance %s\n",
coreref, pr ? "enabled" : "disabled"));
drbg->core = &drbg_cores[coreref];
drbg->pr = pr;
drbg->seeded = 0;
if (drbg->core->flags & DRBG_HMAC)
drbg->d_ops = &drbg_hmac_ops;
else if (drbg->core->flags & DRBG_HASH_MASK)
drbg->d_ops = &drbg_hash_ops;
else if (drbg->core->flags & DRBG_CTR_MASK)
drbg->d_ops = &drbg_ctr_ops;
else
return GPG_ERR_GENERAL;
/* 9.1 step 1 is implicit with the selected DRBG type -- see
* drbg_sec_strength() */
/* 9.1 step 2 is implicit as caller can select prediction resistance
* and the flag is copied into drbg->flags --
* all DRBG types support prediction resistance */
/* 9.1 step 4 is implicit in drbg_sec_strength */
ret = drbg->d_ops->crypto_init(drbg);
if (ret)
goto err;
drbg->V = xcalloc_secure (1, drbg_statelen (drbg));
if (!drbg->V)
goto fini;
drbg->C = xcalloc_secure (1, drbg_statelen (drbg));
if (!drbg->C)
goto fini;
/* scratchpad is only generated for CTR and Hash */
if (drbg->core->flags & DRBG_HMAC)
sb_size = 0;
else if (drbg->core->flags & DRBG_CTR_MASK)
sb_size = drbg_statelen (drbg) + drbg_blocklen (drbg) + /* temp */
drbg_statelen (drbg) + /* df_data */
drbg_blocklen (drbg) + /* pad */
drbg_blocklen (drbg) + /* iv */
drbg_statelen (drbg) + drbg_blocklen (drbg); /* temp */
else
sb_size = drbg_statelen (drbg);
if (0 < sb_size)
{
drbg->scratchpad = xcalloc_secure (1, sb_size);
if (!drbg->scratchpad)
goto fini;
}
dbg (("DRBG: state allocated with scratchpad size %u bytes\n", sb_size));
/* 9.1 step 6 through 11 */
ret = drbg_seed (drbg, pers, 0);
if (ret)
goto fini;
dbg (("DRBG: core %d %s prediction resistance successfully initialized\n",
coreref, pr ? "with" : "without"));
return 0;
fini:
drbg->d_ops->crypto_fini(drbg);
err:
drbg_uninstantiate (drbg);
return ret;
}
/*
* DRBG reseed function as required by SP800-90A
*
* @drbg DRBG state handle
* @addtl Additional input that is mixed into state, may be NULL -- note
* the entropy is pulled by the DRBG internally unconditionally
* as defined in SP800-90A. The additional input is mixed into
* the state in addition to the pulled entropy.
*
* return
* 0 on success
* error value otherwise
*/
static gpg_err_code_t
drbg_reseed (drbg_state_t drbg,drbg_string_t *addtl)
{
gpg_err_code_t ret = 0;
ret = drbg_seed (drbg, addtl, 1);
return ret;
}
/******************************************************************
* Libgcrypt integration code.
******************************************************************/
/***************************************************
* Libgcrypt backend functions to the RNG API code.
***************************************************/
static inline void
drbg_lock (void)
{
gpg_err_code_t ec;
ec = gpgrt_lock_lock (&drbg_lock_var);
if (ec)
log_fatal ("failed to acquire the RNG lock: %s\n", gpg_strerror (ec));
}
static inline void
drbg_unlock (void)
{
gpg_err_code_t ec;
ec = gpgrt_lock_unlock (&drbg_lock_var);
if (ec)
log_fatal ("failed to release the RNG lock: %s\n", gpg_strerror (ec));
}
/* Basic initialization is required to initialize mutexes and
do a few checks on the implementation. */
static void
basic_initialization (void)
{
static int initialized;
if (initialized)
return;
initialized = 1;
/* Make sure that we are still using the values we have
traditionally used for the random levels. */
gcry_assert (GCRY_WEAK_RANDOM == 0
&& GCRY_STRONG_RANDOM == 1
&& GCRY_VERY_STRONG_RANDOM == 2);
}
/****** helper functions where lock must be held by caller *****/
/* Check whether given flags are known to point to an applicable DRBG */
static gpg_err_code_t
drbg_algo_available (u32 flags, int *coreref)
{
int i = 0;
for (i = 0; ARRAY_SIZE (drbg_cores) > i; i++)
{
if ((drbg_cores[i].flags & DRBG_CIPHER_MASK) ==
(flags & DRBG_CIPHER_MASK))
{
*coreref = i;
return 0;
}
}
return GPG_ERR_GENERAL;
}
static gpg_err_code_t
_drbg_init_internal (u32 flags, drbg_string_t *pers)
{
static u32 oldflags;
gpg_err_code_t ret = 0;
int coreref = 0;
int pr = 0;
/* If a caller provides 0 as flags, use the flags of the previous
* initialization, otherwise use the current flags and remember them
* for the next invocation. If no flag is given and no global state
* is set this is the first initialization and we set the default
* type.
*/
if (!flags && !drbg_state)
flags = oldflags = DRBG_DEFAULT_TYPE;
else if (!flags)
flags = oldflags;
else
oldflags = flags;
ret = drbg_algo_available (flags, &coreref);
if (ret)
return ret;
if (drbg_state)
{
drbg_uninstantiate (drbg_state);
}
else
{
drbg_state = xtrycalloc_secure (1, sizeof *drbg_state);
if (!drbg_state)
return gpg_err_code_from_syserror ();
}
if (flags & DRBG_PREDICTION_RESIST)
pr = 1;
ret = drbg_instantiate (drbg_state, pers, coreref, pr);
if (ret)
fips_signal_error ("DRBG cannot be initialized");
else
drbg_state->seed_init_pid = getpid ();
return ret;
}
/************* calls available to common RNG code **************/
/*
* Initialize one DRBG invoked by the libgcrypt API
*/
void
_gcry_rngdrbg_inititialize (int full)
{
basic_initialization ();
if (!full)
return;
drbg_lock ();
if (!drbg_state)
_drbg_init_internal (0, NULL);
drbg_unlock ();
}
/*
* Backend handler function for GCRYCTL_DRBG_REINIT
*
* Select a different DRBG type and initialize it.
* Function checks whether requested DRBG type exists and returns an error in
* case it does not. In case of an error, the previous instantiated DRBG is
* left untouched and alive. Thus, in case of an error, a DRBG is always
* available, even if it is not the chosen one.
*
* Re-initialization will be performed in any case regardless whether flags
* or personalization string are set.
*
* If flags is NULL, do not change current DRBG. If PERS is NULL and
* NPERS is 0, re-initialize without personalization string. If PERS
* is not NULL NPERS must be one and PERS and the first ietm from the
* bufer is take as personalization string.
*/
gpg_err_code_t
_gcry_rngdrbg_reinit (const char *flagstr, gcry_buffer_t *pers, int npers)
{
gpg_err_code_t ret;
unsigned int flags;
/* If PERS is not given we expect NPERS to be zero; if given we
expect a one-item array. */
if ((!pers && npers) || (pers && npers != 1))
return GPG_ERR_INV_ARG;
ret = parse_flag_string (flagstr, &flags);
if (!ret)
{
dbg (("DRBG: reinitialize internal DRBG state with flags %u\n", flags));
drbg_lock ();
if (pers)
{
drbg_string_t persbuf;
drbg_string_fill
(&persbuf, (const unsigned char *)pers[0].data + pers[0].off,
pers[0].len);
ret = _drbg_init_internal (flags, &persbuf);
}
else
ret = _drbg_init_internal (flags, NULL);
drbg_unlock ();
}
return ret;
}
/* Try to close the FDs of the random gather module. This is
* currently only implemented for rndlinux. */
void
_gcry_rngdrbg_close_fds (void)
{
#if USE_RNDLINUX
drbg_lock ();
_gcry_rndlinux_gather_random (NULL, 0, 0, 0);
drbg_unlock ();
#endif
}
/* Print some statistics about the RNG. */
void
_gcry_rngdrbg_dump_stats (void)
{
/* Not yet implemented. */
/* Maybe dumping of reseed counter? */
}
/* This function returns true if no real RNG is available or the
* quality of the RNG has been degraded for test purposes. */
int
_gcry_rngdrbg_is_faked (void)
{
return 0; /* Faked random is not allowed. */
}
/* Add BUFLEN bytes from BUF to the internal random pool. QUALITY
* should be in the range of 0..100 to indicate the goodness of the
* entropy added, or -1 for goodness not known. */
gcry_error_t
_gcry_rngdrbg_add_bytes (const void *buf, size_t buflen, int quality)
{
gpg_err_code_t ret = 0;
drbg_string_t seed;
(void) quality;
_gcry_rngdrbg_inititialize (1); /* Auto-initialize if needed */
if (!drbg_state)
return GPG_ERR_GENERAL;
drbg_string_fill (&seed, (unsigned char *) buf, buflen);
drbg_lock ();
ret = drbg_reseed (drbg_state, &seed);
drbg_unlock ();
return ret;
}
/* This function is to be used for all types of random numbers, including
* nonces
*/
void
_gcry_rngdrbg_randomize (void *buffer, size_t length,
enum gcry_random_level level)
{
(void) level;
_gcry_rngdrbg_inititialize (1); /* Auto-initialize if needed */
drbg_lock ();
if (!drbg_state)
{
fips_signal_error ("DRBG is not initialized");
goto bailout;
}
/* As reseeding changes the entire state of the DRBG, including any
* key, either a re-init or a reseed is sufficient for a fork */
if (drbg_state->seed_init_pid != getpid ())
{
/* We are in a child of us. Perform a reseeding. */
if (drbg_reseed (drbg_state, NULL))
{
fips_signal_error ("reseeding upon fork failed");
log_fatal ("severe error getting random\n");
goto bailout;
}
}
/* potential integer overflow is covered by drbg_generate which
* ensures that length cannot overflow an unsigned int */
if (0 < length)
{
if (!buffer)
goto bailout;
if (drbg_generate_long (drbg_state, buffer, (unsigned int) length, NULL))
log_fatal ("No random numbers generated\n");
}
else
{
drbg_gen_t *data = (drbg_gen_t *)buffer;
/* catch NULL pointer */
if (!data || !data->outbuf)
{
fips_signal_error ("No output buffer provided");
goto bailout;
}
if (drbg_generate_long (drbg_state, data->outbuf, data->outlen,
data->addtl))
log_fatal ("No random numbers generated\n");
}
bailout:
drbg_unlock ();
return;
}
/***************************************************************
* Self-test code
***************************************************************/
/*
* Test vectors from
* http://csrc.nist.gov/groups/STM/cavp/documents/drbg/drbgtestvectors.zip
*/
struct gcry_drbg_test_vector drbg_test_pr[] = {
{
/* .flags = */ "sha256 pr" /* DRBG_PR_HASHSHA256 */,
/* .entropy = */ (unsigned char *)
"\x5d\xf2\x14\xbc\xf6\xb5\x4e\x0b\xf0\x0d\x6f\x2d"
"\xe2\x01\x66\x7b\xd0\xa4\x73\xa4\x21\xdd\xb0\xc0"
"\x51\x79\x09\xf4\xea\xa9\x08\xfa\xa6\x67\xe0\xe1"
"\xd1\x88\xa8\xad\xee\x69\x74\xb3\x55\x06\x9b\xf6",
/* .entropylen = */ 48,
/* .entpra = */ (unsigned char *)
"\xef\x48\x06\xa2\xc2\x45\xf1\x44\xfa\x34\x2c\xeb"
"\x8d\x78\x3c\x09\x8f\x34\x72\x20\xf2\xe7\xfd\x13"
"\x76\x0a\xf6\xdc\x3c\xf5\xc0\x15",
/* .entprb = */ (unsigned char *)
"\x4b\xbe\xe5\x24\xed\x6a\x2d\x0c\xdb\x73\x5e\x09"
"\xf9\xad\x67\x7c\x51\x47\x8b\x6b\x30\x2a\xc6\xde"
"\x76\xaa\x55\x04\x8b\x0a\x72\x95",
/* .entprlen = */ 32,
/* .addtla = */ (unsigned char *)
"\xbe\x13\xdb\x2a\xe9\xa8\xfe\x09\x97\xe1\xce\x5d"
"\xe8\xbb\xc0\x7c\x4f\xcb\x62\x19\x3f\x0f\xd2\xad"
"\xa9\xd0\x1d\x59\x02\xc4\xff\x70",
/* .addtlb = */ (unsigned char *)
"\x6f\x96\x13\xe2\xa7\xf5\x6c\xfe\xdf\x66\xe3\x31"
"\x63\x76\xbf\x20\x27\x06\x49\xf1\xf3\x01\x77\x41"
"\x9f\xeb\xe4\x38\xfe\x67\x00\xcd",
/* .addtllen = */ 32,
/* .pers = */ NULL,
/* .perslen = */ 0,
/* .expected = */ (unsigned char *)
"\x3b\x14\x71\x99\xa1\xda\xa0\x42\xe6\xc8\x85\x32"
"\x70\x20\x32\x53\x9a\xbe\xd1\x1e\x15\xef\xfb\x4c"
"\x25\x6e\x19\x3a\xf0\xb9\xcb\xde\xf0\x3b\xc6\x18"
"\x4d\x85\x5a\x9b\xf1\xe3\xc2\x23\x03\x93\x08\xdb"
"\xa7\x07\x4b\x33\x78\x40\x4d\xeb\x24\xf5\x6e\x81"
"\x4a\x1b\x6e\xa3\x94\x52\x43\xb0\xaf\x2e\x21\xf4"
"\x42\x46\x8e\x90\xed\x34\x21\x75\xea\xda\x67\xb6"
"\xe4\xf6\xff\xc6\x31\x6c\x9a\x5a\xdb\xb3\x97\x13"
"\x09\xd3\x20\x98\x33\x2d\x6d\xd7\xb5\x6a\xa8\xa9"
"\x9a\x5b\xd6\x87\x52\xa1\x89\x2b\x4b\x9c\x64\x60"
"\x50\x47\xa3\x63\x81\x16\xaf\x19",
/* .expectedlen = */ 128,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* flags = */ "hmac sha256 pr" /* DRBG_PR_HMACSHA256 */,
/* .entropy = */ (unsigned char *)
"\x13\x54\x96\xfc\x1b\x7d\x28\xf3\x18\xc9\xa7\x89"
"\xb6\xb3\xc8\x72\xac\x00\xd4\x59\x36\x25\x05\xaf"
"\xa5\xdb\x96\xcb\x3c\x58\x46\x87\xa5\xaa\xbf\x20"
"\x3b\xfe\x23\x0e\xd1\xc7\x41\x0f\x3f\xc9\xb3\x67",
/* .entropylen = */ 48,
/* .entpra = */ (unsigned char *)
"\xe2\xbd\xb7\x48\x08\x06\xf3\xe1\x93\x3c\xac\x79"
"\xa7\x2b\x11\xda\xe3\x2e\xe1\x91\xa5\x02\x19\x57"
"\x20\x28\xad\xf2\x60\xd7\xcd\x45",
/* .entprb = */ (unsigned char *)
"\x8b\xd4\x69\xfc\xff\x59\x95\x95\xc6\x51\xde\x71"
"\x68\x5f\xfc\xf9\x4a\xab\xec\x5a\xcb\xbe\xd3\x66"
"\x1f\xfa\x74\xd3\xac\xa6\x74\x60",
/* .entprlen = */ 32,
/* .addtla = */ NULL,
/* .addtlb = */ NULL,
/* .addtllen = */ 0,
/* .pers = */ (unsigned char *)
"\x64\xb6\xfc\x60\xbc\x61\x76\x23\x6d\x3f\x4a\x0f"
"\xe1\xb4\xd5\x20\x9e\x70\xdd\x03\x53\x6d\xbf\xce"
"\xcd\x56\x80\xbc\xb8\x15\xc8\xaa",
/* .perslen = */ 32,
/* .expected = */ (unsigned char *)
"\x1f\x9e\xaf\xe4\xd2\x46\xb7\x47\x41\x4c\x65\x99"
"\x01\xe9\x3b\xbb\x83\x0c\x0a\xb0\xc1\x3a\xe2\xb3"
"\x31\x4e\xeb\x93\x73\xee\x0b\x26\xc2\x63\xa5\x75"
"\x45\x99\xd4\x5c\x9f\xa1\xd4\x45\x87\x6b\x20\x61"
"\x40\xea\x78\xa5\x32\xdf\x9e\x66\x17\xaf\xb1\x88"
"\x9e\x2e\x23\xdd\xc1\xda\x13\x97\x88\xa5\xb6\x5e"
"\x90\x14\x4e\xef\x13\xab\x5c\xd9\x2c\x97\x9e\x7c"
"\xd7\xf8\xce\xea\x81\xf5\xcd\x71\x15\x49\x44\xce"
"\x83\xb6\x05\xfb\x7d\x30\xb5\x57\x2c\x31\x4f\xfc"
"\xfe\x80\xb6\xc0\x13\x0c\x5b\x9b\x2e\x8f\x3d\xfc"
"\xc2\xa3\x0c\x11\x1b\x80\x5f\xf3",
/* .expectedlen = */ 128,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* .flags = */ "aes sym128 pr", /* DRBG_PR_CTRAES128 */
/* .entropy = */ (unsigned char *)
"\x92\x89\x8f\x31\xfa\x1c\xff\x6d\x18\x2f\x26\x06"
"\x43\xdf\xf8\x18\xc2\xa4\xd9\x72\xc3\xb9\xb6\x97",
/* .entropylen = */ 24,
/* .entpra = */ (unsigned char *)
"\x20\x72\x8a\x06\xf8\x6f\x8d\xd4\x41\xe2\x72\xb7"
"\xc4\x2c\xe8\x10",
/* .entprb = */ (unsigned char *)
"\x3d\xb0\xf0\x94\xf3\x05\x50\x33\x17\x86\x3e\x22"
"\x08\xf7\xa5\x01",
/* .entprlen = */ 16,
/* .addtla = */ (unsigned char *)
"\x1a\x40\xfa\xe3\xcc\x6c\x7c\xa0\xf8\xda\xba\x59"
"\x23\x6d\xad\x1d",
/* .addtlb = */ (unsigned char *)
"\x9f\x72\x76\x6c\xc7\x46\xe5\xed\x2e\x53\x20\x12"
"\xbc\x59\x31\x8c",
/* .addtllen = */ 16,
/* .pers = */ (unsigned char *)
"\xea\x65\xee\x60\x26\x4e\x7e\xb6\x0e\x82\x68\xc4"
"\x37\x3c\x5c\x0b",
/* .perslen = */ 16,
/* .expected = */ (unsigned char *)
"\x5a\x35\x39\x87\x0f\x4d\x22\xa4\x09\x24\xee\x71"
"\xc9\x6f\xac\x72\x0a\xd6\xf0\x88\x82\xd0\x83\x28"
"\x73\xec\x3f\x93\xd8\xab\x45\x23\xf0\x7e\xac\x45"
"\x14\x5e\x93\x9f\xb1\xd6\x76\x43\x3d\xb6\xe8\x08"
"\x88\xf6\xda\x89\x08\x77\x42\xfe\x1a\xf4\x3f\xc4"
"\x23\xc5\x1f\x68",
/* .expectedlen = */ 64,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
}
};
struct gcry_drbg_test_vector drbg_test_nopr[] = {
{
/* .flags = */ "sha256" /* DRBG_NOPR_HASHSHA256 */,
/* .entropy = */ (unsigned char *)
"\x73\xd3\xfb\xa3\x94\x5f\x2b\x5f\xb9\x8f\xf6\x9c"
"\x8a\x93\x17\xae\x19\xc3\x4c\xc3\xd6\xca\xa3\x2d"
"\x16\xfc\x42\xd2\x2d\xd5\x6f\x56\xcc\x1d\x30\xff"
"\x9e\x06\x3e\x09\xce\x58\xe6\x9a\x35\xb3\xa6\x56",
/* .entropylen = */ 48,
/* .entpra = */ NULL,
/* .entprb = */ NULL,
/* .entprlen = */ 0,
/* .addtla = */ (unsigned char *)
"\xf4\xd5\x98\x3d\xa8\xfc\xfa\x37\xb7\x54\x67\x73"
"\xc7\xc3\xdd\x47\x34\x71\x02\x5d\xc1\xa0\xd3\x10"
"\xc1\x8b\xbd\xf5\x66\x34\x6f\xdd",
/* .addtlb = */ (unsigned char *)
"\xf7\x9e\x6a\x56\x0e\x73\xe9\xd9\x7a\xd1\x69\xe0"
"\x6f\x8c\x55\x1c\x44\xd1\xce\x6f\x28\xcc\xa4\x4d"
"\xa8\xc0\x85\xd1\x5a\x0c\x59\x40",
/* .addtllen = */ 32,
/* .pers = */ NULL,
/* .perslen = */ 0,
/* .expected = */ (unsigned char *)
"\x71\x7b\x93\x46\x1a\x40\xaa\x35\xa4\xaa\xc5\xe7"
"\x6d\x5b\x5b\x8a\xa0\xdf\x39\x7d\xae\x71\x58\x5b"
"\x3c\x7c\xb4\xf0\x89\xfa\x4a\x8c\xa9\x5c\x54\xc0"
"\x40\xdf\xbc\xce\x26\x81\x34\xf8\xba\x7d\x1c\xe8"
"\xad\x21\xe0\x74\xcf\x48\x84\x30\x1f\xa1\xd5\x4f"
"\x81\x42\x2f\xf4\xdb\x0b\x23\xf8\x73\x27\xb8\x1d"
"\x42\xf8\x44\x58\xd8\x5b\x29\x27\x0a\xf8\x69\x59"
"\xb5\x78\x44\xeb\x9e\xe0\x68\x6f\x42\x9a\xb0\x5b"
"\xe0\x4e\xcb\x6a\xaa\xe2\xd2\xd5\x33\x25\x3e\xe0"
"\x6c\xc7\x6a\x07\xa5\x03\x83\x9f\xe2\x8b\xd1\x1c"
"\x70\xa8\x07\x59\x97\xeb\xf6\xbe",
/* .expectedlen = */ 128,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* .flags = */ "hmac sha256" /* DRBG_NOPR_HMACSHA256 */,
/* .entropy = */ (unsigned char *)
"\x8d\xf0\x13\xb4\xd1\x03\x52\x30\x73\x91\x7d\xdf"
"\x6a\x86\x97\x93\x05\x9e\x99\x43\xfc\x86\x54\x54"
"\x9e\x7a\xb2\x2f\x7c\x29\xf1\x22\xda\x26\x25\xaf"
"\x2d\xdd\x4a\xbc\xce\x3c\xf4\xfa\x46\x59\xd8\x4e",
/* .entropylen = */ 48,
/* .entpra = */ NULL,
/* .entprb = */ NULL,
/* .entprlen = */ 0,
/* .addtla = */ NULL,
/* .addtlb = */ NULL,
/* .addtllen = */ 0,
/* .pers = */ (unsigned char *)
"\xb5\x71\xe6\x6d\x7c\x33\x8b\xc0\x7b\x76\xad\x37"
"\x57\xbb\x2f\x94\x52\xbf\x7e\x07\x43\x7a\xe8\x58"
"\x1c\xe7\xbc\x7c\x3a\xc6\x51\xa9",
/* .perslen = */ 32,
/* .expected = */ (unsigned char *)
"\xb9\x1c\xba\x4c\xc8\x4f\xa2\x5d\xf8\x61\x0b\x81"
"\xb6\x41\x40\x27\x68\xa2\x09\x72\x34\x93\x2e\x37"
"\xd5\x90\xb1\x15\x4c\xbd\x23\xf9\x74\x52\xe3\x10"
"\xe2\x91\xc4\x51\x46\x14\x7f\x0d\xa2\xd8\x17\x61"
"\xfe\x90\xfb\xa6\x4f\x94\x41\x9c\x0f\x66\x2b\x28"
"\xc1\xed\x94\xda\x48\x7b\xb7\xe7\x3e\xec\x79\x8f"
"\xbc\xf9\x81\xb7\x91\xd1\xbe\x4f\x17\x7a\x89\x07"
"\xaa\x3c\x40\x16\x43\xa5\xb6\x2b\x87\xb8\x9d\x66"
"\xb3\xa6\x0e\x40\xd4\xa8\xe4\xe9\xd8\x2a\xf6\xd2"
"\x70\x0e\x6f\x53\x5c\xdb\x51\xf7\x5c\x32\x17\x29"
"\x10\x37\x41\x03\x0c\xcc\x3a\x56",
/* .expectedlen = */ 128,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* .flags = */ "aes sym128" /* DRBG_NOPR_CTRAES128 */,
/* .entropy = */ (unsigned char *)
"\xc0\x70\x1f\x92\x50\x75\x8f\xcd\xf2\xbe\x73\x98"
"\x80\xdb\x66\xeb\x14\x68\xb4\xa5\x87\x9c\x2d\xa6",
/* .entropylen = */ 24,
/* .entpra = */ NULL,
/* .entprb = */ NULL,
/* .entprlen = */ 0,
/* .addtla = */ (unsigned char *)
"\xf9\x01\xf8\x16\x7a\x1d\xff\xde\x8e\x3c\x83\xe2"
"\x44\x85\xe7\xfe",
/* .addtlb = */ (unsigned char *)
"\x17\x1c\x09\x38\xc2\x38\x9f\x97\x87\x60\x55\xb4"
"\x82\x16\x62\x7f",
/* .addtllen = */ 16,
/* .pers = */ (unsigned char *)
"\x80\x08\xae\xe8\xe9\x69\x40\xc5\x08\x73\xc7\x9f"
"\x8e\xcf\xe0\x02",
/* .perslen = */ 16,
/* .expected = */ (unsigned char *)
"\x97\xc0\xc0\xe5\xa0\xcc\xf2\x4f\x33\x63\x48\x8a"
"\xdb\x13\x0a\x35\x89\xbf\x80\x65\x62\xee\x13\x95"
"\x7c\x33\xd3\x7d\xf4\x07\x77\x7a\x2b\x65\x0b\x5f"
"\x45\x5c\x13\xf1\x90\x77\x7f\xc5\x04\x3f\xcc\x1a"
"\x38\xf8\xcd\x1b\xbb\xd5\x57\xd1\x4a\x4c\x2e\x8a"
"\x2b\x49\x1e\x5c",
/* .expectedlen = */ 64,
/* .entropyreseed = */ NULL,
/* .entropyreseed_len = */ 0,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* .flags = */ "sha1" /* DRBG_NOPR_HASHSHA1 */,
/* .entropy = */ (unsigned char *)
"\x16\x10\xb8\x28\xcc\xd2\x7d\xe0\x8c\xee\xa0\x32"
"\xa2\x0e\x92\x08\x49\x2c\xf1\x70\x92\x42\xf6\xb5",
/* .entropylen = */ 24,
/* .entpra = */ NULL,
/* .entprb = */ NULL,
/* .entprlen = */ 0,
/* .addtla = */ NULL,
/* .addtlb = */ NULL,
/* .addtllen = */ 0,
/* .pers = */ NULL,
/* .perslen = */ 0,
/* .expected = */ (unsigned char *)
"\x56\xf3\x3d\x4f\xdb\xb9\xa5\xb6\x4d\x26\x23\x44"
"\x97\xe9\xdc\xb8\x77\x98\xc6\x8d\x08\xf7\xc4\x11"
"\x99\xd4\xbd\xdf\x97\xeb\xbf\x6c\xb5\x55\x0e\x5d"
"\x14\x9f\xf4\xd5\xbd\x0f\x05\xf2\x5a\x69\x88\xc1"
"\x74\x36\x39\x62\x27\x18\x4a\xf8\x4a\x56\x43\x35"
"\x65\x8e\x2f\x85\x72\xbe\xa3\x33\xee\xe2\xab\xff"
"\x22\xff\xa6\xde\x3e\x22\xac\xa2",
/* .expectedlen = */ 80,
/* .entropyreseed = */ (unsigned char *)
"\x72\xd2\x8c\x90\x8e\xda\xf9\xa4\xd1\xe5\x26\xd8"
"\xf2\xde\xd5\x44",
/* .entropyreseed_len = */ 16,
/* .addtl_reseed = */ NULL,
/* .addtl_reseed_len = */ 0
},
{
/* .flags = */ "sha1" /* DRBG_NOPR_HASHSHA1 */,
/* .entropy = */ (unsigned char *)
"\xd9\xba\xb5\xce\xdc\xa9\x6f\x61\x78\xd6\x45\x09"
"\xa0\xdf\xdc\x5e\xda\xd8\x98\x94\x14\x45\x0e\x01",
/* .entropylen = */ 24,
/* .entpra = */ NULL,
/* .entprb = */ NULL,
/* .entprlen = */ 0,
/* .addtla = */ (unsigned char *)
"\x04\xfa\x28\x95\xaa\x5a\x6f\x8c\x57\x43\x34\x3b"
"\x80\x5e\x5e\xa4",
/* .addtlb = */ (unsigned char *)
"\xdf\x5d\xc4\x59\xdf\xf0\x2a\xa2\xf0\x52\xd7\x21"
"\xec\x60\x72\x30",
/* .addtllen = */ 16,
/* .pers = */ NULL,
/* .perslen = */ 0,
/* .expected = */ (unsigned char *)
"\xc4\x8b\x89\xf9\xda\x3f\x74\x82\x45\x55\x5d\x5d"
"\x03\x3b\x69\x3d\xd7\x1a\x4d\xf5\x69\x02\x05\xce"
"\xfc\xd7\x20\x11\x3c\xc2\x4e\x09\x89\x36\xff\x5e"
"\x77\xb5\x41\x53\x58\x70\xb3\x39\x46\x8c\xdd\x8d"
"\x6f\xaf\x8c\x56\x16\x3a\x70\x0a\x75\xb2\x3e\x59"
"\x9b\x5a\xec\xf1\x6f\x3b\xaf\x6d\x5f\x24\x19\x97"
"\x1f\x24\xf4\x46\x72\x0f\xea\xbe",
/* .expectedlen = */ 80,
/* .entropyreseed = */ (unsigned char *)
"\xc6\xba\xd0\x74\xc5\x90\x67\x86\xf5\xe1\xf3\x20"
"\x99\xf5\xb4\x91",
/* .entropyreseed_len = */ 16,
/* .addtl_reseed = */ (unsigned char *)
"\x3e\x6b\xf4\x6f\x4d\xaa\x38\x25\xd7\x19\x4e\x69"
"\x4e\x77\x52\xf7",
/* .addtl_reseed_len = */ 16
}
};
/*
* Tests implement the CAVS test approach as documented in
* http://csrc.nist.gov/groups/STM/cavp/documents/drbg/DRBGVS.pdf
*/
/*
* CAVS test
*
* This function is not static as it is needed for as a private API
* call for the CAVS test tool.
*/
gpg_err_code_t
_gcry_rngdrbg_cavs_test (struct gcry_drbg_test_vector *test, unsigned char *buf)
{
gpg_err_code_t ret = 0;
drbg_state_t drbg = NULL;
struct drbg_test_data_s test_data;
drbg_string_t addtl, pers, testentropy;
int coreref = 0;
int pr = 0;
u32 flags;
ret = parse_flag_string (test->flagstr, &flags);
if (ret)
goto outbuf;
ret = drbg_algo_available (flags, &coreref);
if (ret)
goto outbuf;
drbg = xtrycalloc_secure (1, sizeof *drbg);
if (!drbg)
{
ret = gpg_err_code_from_syserror ();
goto outbuf;
}
if ((flags & DRBG_PREDICTION_RESIST))
pr = 1;
test_data.testentropy = &testentropy;
drbg_string_fill (&testentropy, test->entropy, test->entropylen);
drbg->test_data = &test_data;
drbg_string_fill (&pers, test->pers, test->perslen);
ret = drbg_instantiate (drbg, &pers, coreref, pr);
if (ret)
goto outbuf;
if (test->entropyreseed)
{
drbg_string_fill (&testentropy, test->entropyreseed,
test->entropyreseed_len);
drbg_string_fill (&addtl, test->addtl_reseed,
test->addtl_reseed_len);
if (drbg_reseed (drbg, &addtl))
goto outbuf;
}
drbg_string_fill (&addtl, test->addtla, test->addtllen);
if (test->entpra)
{
drbg_string_fill (&testentropy, test->entpra, test->entprlen);
drbg->test_data = &test_data;
}
drbg_generate_long (drbg, buf, test->expectedlen, &addtl);
drbg_string_fill (&addtl, test->addtlb, test->addtllen);
if (test->entprb)
{
drbg_string_fill (&testentropy, test->entprb, test->entprlen);
drbg->test_data = &test_data;
}
drbg_generate_long (drbg, buf, test->expectedlen, &addtl);
drbg_uninstantiate (drbg);
outbuf:
xfree (drbg);
return ret;
}
/*
* Invoke the CAVS test and perform the final check whether the
* calculated random value matches the expected one.
*
* This function is not static as it is needed for as a private API
* call for the CAVS test tool.
*/
gpg_err_code_t
_gcry_rngdrbg_healthcheck_one (struct gcry_drbg_test_vector * test)
{
gpg_err_code_t ret = GPG_ERR_ENOMEM;
unsigned char *buf = xcalloc_secure (1, test->expectedlen);
if (!buf)
return GPG_ERR_ENOMEM;
ret = _gcry_rngdrbg_cavs_test (test, buf);
/* FIXME: The next line is wrong. */
ret = memcmp (test->expected, buf, test->expectedlen);
xfree (buf);
return ret;
}
/*
* Tests as defined in 11.3.2 in addition to the cipher tests: testing
* of the error handling.
*
* Note, testing the reseed counter is not done as an automatic reseeding
* is performed in drbg_generate when the reseed counter is too large.
*/
static gpg_err_code_t
drbg_healthcheck_sanity (struct gcry_drbg_test_vector *test)
{
unsigned int len = 0;
drbg_state_t drbg = NULL;
gpg_err_code_t ret = GPG_ERR_GENERAL;
gpg_err_code_t tmpret = GPG_ERR_GENERAL;
struct drbg_test_data_s test_data;
drbg_string_t addtl, testentropy;
int coreref = 0;
unsigned char *buf = NULL;
size_t max_addtllen, max_request_bytes;
u32 flags;
/* only perform test in FIPS mode */
if (0 == fips_mode ())
return 0;
ret = parse_flag_string (test->flagstr, &flags);
if (ret)
return ret;
ret = GPG_ERR_GENERAL; /* Fixme: Improve handling of RET. */
buf = xtrycalloc_secure (1, test->expectedlen);
if (!buf)
return gpg_err_code_from_syserror ();
tmpret = drbg_algo_available (flags, &coreref);
if (tmpret)
goto outbuf;
drbg = xtrycalloc_secure (1, sizeof *drbg);
if (!drbg)
{
ret = gpg_err_code_from_syserror ();
goto outbuf;
}
/* if the following tests fail, it is likely that there is a buffer
* overflow and we get a SIGSEV */
ret = drbg_instantiate (drbg, NULL, coreref, 1);
if (ret)
goto outbuf;
max_addtllen = drbg_max_addtl ();
max_request_bytes = drbg_max_request_bytes ();
/* overflow addtllen with additional info string */
drbg_string_fill (&addtl, test->addtla, (max_addtllen + 1));
len = drbg_generate (drbg, buf, test->expectedlen, &addtl);
if (len)
goto outdrbg;
/* overflow max_bits */
len = drbg_generate (drbg, buf, (max_request_bytes + 1), NULL);
if (len)
goto outdrbg;
drbg_uninstantiate (drbg);
/* test failing entropy source as defined in 11.3.2 */
test_data.testentropy = NULL;
test_data.fail_seed_source = 1;
drbg->test_data = &test_data;
tmpret = drbg_instantiate (drbg, NULL, coreref, 0);
if (!tmpret)
goto outdrbg;
test_data.fail_seed_source = 0;
test_data.testentropy = &testentropy;
drbg_string_fill (&testentropy, test->entropy, test->entropylen);
/* overflow max addtllen with personalization string */
tmpret = drbg_instantiate (drbg, &addtl, coreref, 0);
if (!tmpret)
goto outdrbg;
dbg (("DRBG: Sanity tests for failure code paths successfully completed\n"));
ret = 0;
outdrbg:
drbg_uninstantiate (drbg);
outbuf:
xfree (buf);
xfree (drbg);
return ret;
}
/*
* DRBG Healthcheck function as required in SP800-90A
*
* return:
* 0 on success (all tests pass)
* >0 on error (return code indicate the number of failures)
*/
static int
drbg_healthcheck (void)
{
int ret = 0;
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_nopr[0]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_nopr[1]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_nopr[2]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_nopr[3]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_nopr[4]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_pr[0]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_pr[1]);
ret += _gcry_rngdrbg_healthcheck_one (&drbg_test_pr[2]);
ret += drbg_healthcheck_sanity (&drbg_test_nopr[0]);
return ret;
}
/* Run the self-tests. */
gcry_error_t
_gcry_rngdrbg_selftest (selftest_report_func_t report)
{
gcry_err_code_t ec;
const char *errtxt = NULL;
drbg_lock ();
if (0 != drbg_healthcheck ())
errtxt = "RNG output does not match known value";
drbg_unlock ();
if (report && errtxt)
report ("random", 0, "KAT", errtxt);
ec = errtxt ? GPG_ERR_SELFTEST_FAILED : 0;
return gpg_error (ec);
}
/***************************************************************
* Cipher invocations requested by DRBG
***************************************************************/
static gpg_err_code_t
drbg_hash_init (drbg_state_t drbg)
{
gcry_md_hd_t hd;
gpg_error_t err;
err = _gcry_md_open (&hd, drbg->core->backend_cipher, 0);
if (err)
return err;
drbg->priv_data = hd;
return 0;
}
static gpg_err_code_t
drbg_hmac_init (drbg_state_t drbg)
{
gcry_md_hd_t hd;
gpg_error_t err;
err = _gcry_md_open (&hd, drbg->core->backend_cipher, GCRY_MD_FLAG_HMAC);
if (err)
return err;
drbg->priv_data = hd;
return 0;
}
static gpg_err_code_t
drbg_hmac_setkey (drbg_state_t drbg, const unsigned char *key)
{
gcry_md_hd_t hd = (gcry_md_hd_t)drbg->priv_data;
return _gcry_md_setkey (hd, key, drbg_statelen (drbg));
}
static void
drbg_hash_fini (drbg_state_t drbg)
{
gcry_md_hd_t hd = (gcry_md_hd_t)drbg->priv_data;
_gcry_md_close (hd);
}
static byte *
drbg_hash (drbg_state_t drbg, const drbg_string_t *buf)
{
gcry_md_hd_t hd = (gcry_md_hd_t)drbg->priv_data;
_gcry_md_reset(hd);
for (; NULL != buf; buf = buf->next)
_gcry_md_write (hd, buf->buf, buf->len);
_gcry_md_final (hd);
return _gcry_md_read (hd, drbg->core->backend_cipher);
}
static void
drbg_sym_fini (drbg_state_t drbg)
{
gcry_cipher_hd_t hd = (gcry_cipher_hd_t)drbg->priv_data;
if (hd)
_gcry_cipher_close (hd);
if (drbg->ctr_handle)
_gcry_cipher_close (drbg->ctr_handle);
if (drbg->ctr_null)
free(drbg->ctr_null);
}
static gpg_err_code_t
drbg_sym_init (drbg_state_t drbg)
{
gcry_cipher_hd_t hd;
gpg_error_t err;
drbg->ctr_null = calloc(1, DRBG_CTR_NULL_LEN);
if (!drbg->ctr_null)
return GPG_ERR_ENOMEM;
err = _gcry_cipher_open (&hd, drbg->core->backend_cipher,
GCRY_CIPHER_MODE_ECB, 0);
if (err)
{
drbg_sym_fini (drbg);
return err;
}
drbg->priv_data = hd;
err = _gcry_cipher_open (&drbg->ctr_handle, drbg->core->backend_cipher,
GCRY_CIPHER_MODE_CTR, 0);
if (err)
{
drbg_sym_fini (drbg);
return err;
}
if (drbg_blocklen (drbg) !=
_gcry_cipher_get_algo_blklen (drbg->core->backend_cipher))
{
drbg_sym_fini (drbg);
return -GPG_ERR_NO_ERROR;
}
return 0;
}
static gpg_err_code_t
drbg_sym_setkey (drbg_state_t drbg, const unsigned char *key)
{
gcry_cipher_hd_t hd = (gcry_cipher_hd_t)drbg->priv_data;
return _gcry_cipher_setkey (hd, key, drbg_keylen (drbg));
}
static gpg_err_code_t
drbg_sym (drbg_state_t drbg, unsigned char *outval, const drbg_string_t *buf)
{
gcry_cipher_hd_t hd = (gcry_cipher_hd_t)drbg->priv_data;
_gcry_cipher_reset(hd);
if (drbg_blocklen (drbg) < buf->len)
return -GPG_ERR_NO_ERROR;
/* in is only component */
return _gcry_cipher_encrypt (hd, outval, drbg_blocklen (drbg), buf->buf,
buf->len);
}
static gpg_err_code_t
drbg_sym_ctr (drbg_state_t drbg,
const unsigned char *inbuf, unsigned int inbuflen,
unsigned char *outbuf, unsigned int outbuflen)
{
gpg_error_t err;
_gcry_cipher_reset(drbg->ctr_handle);
err = _gcry_cipher_setctr(drbg->ctr_handle, drbg->V, drbg_blocklen (drbg));
if (err)
return err;
while (outbuflen)
{
unsigned int cryptlen = (inbuflen > outbuflen) ? outbuflen : inbuflen;
err = _gcry_cipher_encrypt (drbg->ctr_handle, outbuf, cryptlen, inbuf,
cryptlen);
if (err)
return err;
outbuflen -= cryptlen;
outbuf += cryptlen;
}
return _gcry_cipher_getctr(drbg->ctr_handle, drbg->V, drbg_blocklen (drbg));
}

File Metadata

Mime Type
text/x-c
Expires
Tue, Apr 14, 9:22 PM (3 h, 47 m)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
fd/7d/8722d3a6cf02242389e7f5448290

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