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Change DH_get_nid() to set the value of q if it is not already set

Browse Source 
Fixes #11108.

It only sets q if a valid named group is found.
The function signature was recently changed to pass a non const DH pointer
in order to allow the nid to be cached internally. As an extension of this
the value of q can now also be set as q is always known for named groups.
The length field is also set if q is set.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/11114)
This commit is contained in:
Shane Lontis 2020-03-07 07:47:58 +10:00
parent f529fc7d53
commit 55f02cb684
11 changed files with 230 additions and 102 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

142
crypto/dh/dh_group_params.c
View File

@ -22,6 +22,33 @@
#include <openssl/objects.h>
#include "crypto/bn_dh.h"
#include "crypto/dh.h"
#include "crypto/security_bits.h"
#define FFDHE(sz) { NID_ffdhe##sz, sz, &_bignum_ffdhe##sz##_p }
#define MODP(sz) { NID_modp_##sz, sz, &_bignum_modp_##sz##_p }
typedef struct safe_prime_group_st {
int nid;
int32_t nbits;
const BIGNUM *p;
} SP_GROUP;
static const SP_GROUP sp_groups[] = {
FFDHE(2048),
FFDHE(3072),
FFDHE(4096),
FFDHE(6144),
FFDHE(8192),
#ifndef FIPS_MODE
MODP(1536),
#endif
MODP(2048),
MODP(3072),
MODP(4096),
MODP(6144),
MODP(8192),
};
#ifndef FIPS_MODE
static DH *dh_new_by_nid_with_ctx(OPENSSL_CTX *libctx, int nid);
@ -54,40 +81,24 @@ static DH *dh_param_init(OPENSSL_CTX *libctx, int nid, const BIGNUM *p,
static DH *dh_new_by_nid_with_ctx(OPENSSL_CTX *libctx, int nid)
{
/*
* The last parameter specified in these fields is
* 2 * max_target_security_strength.
* See SP800-56Ar3 Table(s) 25 & 26.
*/
switch (nid) {
case NID_ffdhe2048:
return dh_param_init(libctx, nid, &_bignum_ffdhe2048_p, 225);
case NID_ffdhe3072:
return dh_param_init(libctx, nid, &_bignum_ffdhe3072_p, 275);
case NID_ffdhe4096:
return dh_param_init(libctx, nid, &_bignum_ffdhe4096_p, 325);
case NID_ffdhe6144:
return dh_param_init(libctx, nid, &_bignum_ffdhe6144_p, 375);
case NID_ffdhe8192:
return dh_param_init(libctx, nid, &_bignum_ffdhe8192_p, 400);
#ifndef FIPS_MODE
case NID_modp_1536:
return dh_param_init(libctx, nid, &_bignum_modp_1536_p, 190);
#endif
case NID_modp_2048:
return dh_param_init(libctx, nid, &_bignum_modp_2048_p, 225);
case NID_modp_3072:
return dh_param_init(libctx, nid, &_bignum_modp_3072_p, 275);
case NID_modp_4096:
return dh_param_init(libctx, nid, &_bignum_modp_4096_p, 325);
case NID_modp_6144:
return dh_param_init(libctx, nid, &_bignum_modp_6144_p, 375);
case NID_modp_8192:
return dh_param_init(libctx, nid, &_bignum_modp_8192_p, 400);
default:
DHerr(0, DH_R_INVALID_PARAMETER_NID);
return NULL;
int i;
for (i = 0; i < (int)OSSL_NELEM(sp_groups); ++i) {
if (sp_groups[i].nid == nid) {
int max_target_security_strength =
ifc_ffc_compute_security_bits(sp_groups[i].nbits);
/*
* The last parameter specified here is
* 2 * max_target_security_strength.
* See SP800-56Ar3 Table(s) 25 & 26.
*/
return dh_param_init(libctx, nid, sp_groups[i].p,
2 * max_target_security_strength);
}
}
DHerr(0, DH_R_INVALID_PARAMETER_NID);
return NULL;
}
DH *DH_new_by_nid(int nid)
@ -98,49 +109,44 @@ DH *DH_new_by_nid(int nid)
int DH_get_nid(DH *dh)
{
int nid = dh->params.nid;
BIGNUM *q = NULL;
int i, nid;
if (dh == NULL)
return NID_undef;
nid = dh->params.nid;
/* Just return if it is already cached */
if (nid != NID_undef)
return nid;
if (BN_get_word(dh->params.g) != 2)
return NID_undef;
if (!BN_cmp(dh->params.p, &_bignum_ffdhe2048_p))
nid = NID_ffdhe2048;
else if (!BN_cmp(dh->params.p, &_bignum_ffdhe3072_p))
nid = NID_ffdhe3072;
else if (!BN_cmp(dh->params.p, &_bignum_ffdhe4096_p))
nid = NID_ffdhe4096;
else if (!BN_cmp(dh->params.p, &_bignum_ffdhe6144_p))
nid = NID_ffdhe6144;
else if (!BN_cmp(dh->params.p, &_bignum_ffdhe8192_p))
nid = NID_ffdhe8192;
#ifndef FIPS_MODE
else if (!BN_cmp(dh->params.p, &_bignum_modp_1536_p))
nid = NID_modp_1536;
#endif
else if (!BN_cmp(dh->params.p, &_bignum_modp_2048_p))
nid = NID_modp_2048;
else if (!BN_cmp(dh->params.p, &_bignum_modp_3072_p))
nid = NID_modp_3072;
else if (!BN_cmp(dh->params.p, &_bignum_modp_4096_p))
nid = NID_modp_4096;
else if (!BN_cmp(dh->params.p, &_bignum_modp_6144_p))
nid = NID_modp_6144;
else if (!BN_cmp(dh->params.p, &_bignum_modp_8192_p))
nid = NID_modp_8192;
else
return NID_undef;
/* Verify q is correct if it exists - reset the nid if it is not correct */
if (dh->params.q != NULL) {
BIGNUM *q = BN_dup(dh->params.p);
for (i = 0; i < (int)OSSL_NELEM(sp_groups); ++i) {
/* If a matching p is found then we will break out of the loop */
if (!BN_cmp(dh->params.p, sp_groups[i].p)) {
/* Set q = (p - 1) / 2 (p is known to be odd so just shift right ) */
q = BN_dup(dh->params.p);
/* Check q = p * 2 + 1 we already know q is odd, so just shift right */
if (q == NULL || !BN_rshift1(q, q) || (BN_cmp(dh->params.q, q) != 0))
nid = NID_undef;
BN_free(q);
if (q == NULL || !BN_rshift1(q, q))
break; /* returns nid = NID_undef on failure */
/* Verify q is correct if it exists */
if (dh->params.q != NULL) {
if (BN_cmp(dh->params.q, q) != 0)
break; /* returns nid = NID_undef if q does not match */
} else {
/* assign the calculated q */
dh->params.q = q;
q = NULL; /* set to NULL so it is not freed */
}
dh->params.nid = sp_groups[i].nid; /* cache the nid */
dh->length = 2 * ifc_ffc_compute_security_bits(sp_groups[i].nbits);
dh->dirty_cnt++;
break;
}
}
dh->params.nid = nid; /* cache the nid */
BN_free(q);
return nid;
}

3
crypto/dh/dh_key.c
View File

@ -251,8 +251,7 @@ static int generate_key(DH *dh)
* (where s = max security strength supported).
* N = dh->length (N = maximum bit length of private key)
*/
if (dh->length == 0
|| dh->params.q == NULL
if (dh->params.q == NULL
|| dh->length > BN_num_bits(dh->params.q))
goto err;
if (!ffc_generate_private_key(ctx, &dh->params, dh->length,

15
crypto/dh/dh_lib.c
View File

@ -211,11 +211,16 @@ int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
ffc_params_set0_pqg(&dh->params, p, q, g);
dh->params.nid = NID_undef;
DH_get_nid(dh); /* Check if this is a named group and cache it */
if (q != NULL)
dh->length = BN_num_bits(q);
/*
* Check if this is a named group. If it finds a named group then the
* 'q' and 'length' value are either already set or are set by the
* call.
*/
if (DH_get_nid(dh) == NID_undef) {
/* If its not a named group then set the 'length' if q is not NULL */
if (q != NULL)
dh->length = BN_num_bits(q);
}
dh->dirty_cnt++;
return 1;
}

11
crypto/ffc/ffc_key_generate.c
View File

@ -36,13 +36,19 @@ int ffc_generate_private_key(BN_CTX *ctx, const FFC_PARAMS *params,
int ffc_generate_private_key_fips(BN_CTX *ctx, const FFC_PARAMS *params,
int N, int s, BIGNUM *priv)
{
int ret = 0;
int ret = 0, qbits = BN_num_bits(params->q);
BIGNUM *m, *two_powN = NULL;
/* Step (2) : check range of N */
if (N < 2 * s || N > BN_num_bits(params->q))
if (N < 2 * s || N > qbits)
return 0;
/* Deal with the edge case where the value of N is not set */
if (N == 0) {
N = qbits;
s = N / 2;
}
two_powN = BN_new();
/* 2^N */
if (two_powN == NULL || !BN_lshift(two_powN, BN_value_one(), N))
@ -50,6 +56,7 @@ int ffc_generate_private_key_fips(BN_CTX *ctx, const FFC_PARAMS *params,
/* Step (5) : M = min(2 ^ N, q) */
m = (BN_cmp(two_powN, params->q) > 0) ? params->q : two_powN;
do {
/* Steps (3, 4 & 7) : c + 1 = 1 + random[0..2^N - 1] */
if (!BN_priv_rand_range_ex(priv, two_powN, ctx)

16
crypto/rsa/rsa_lib.c
View File

@ -23,6 +23,7 @@
#include "crypto/bn.h"
#include "crypto/evp.h"
#include "crypto/rsa.h"
#include "crypto/security_bits.h"
#include "rsa_local.h"
static RSA *rsa_new_intern(ENGINE *engine, OPENSSL_CTX *libctx);
@ -281,11 +282,20 @@ static uint32_t ilog_e(uint64_t v)
* NIST SP 800-56B rev 2 Appendix D: Maximum Security Strength Estimates for IFC
* Modulus Lengths.
*
* Note that this formula is also referred to in SP800-56A rev3 Appendix D:
* for FFC safe prime groups for modp and ffdhe.
* After Table 25 and Table 26 it refers to
* "The maximum security strength estimates were calculated using the formula in
* Section 7.5 of the FIPS 140 IG and rounded to the nearest multiple of eight
* bits".
*
* The formula is:
*
* E = \frac{1.923 \sqrt[3]{nBits \cdot log_e(2)}
* \cdot(log_e(nBits \cdot log_e(2))^{2/3} - 4.69}{log_e(2)}
* The two cube roots are merged together here.
*/
uint16_t rsa_compute_security_bits(int n)
uint16_t ifc_ffc_compute_security_bits(int n)
{
uint64_t x;
uint32_t lx;
@ -322,6 +332,8 @@ uint16_t rsa_compute_security_bits(int n)
return (y + 4) & ~7;
}
int RSA_security_bits(const RSA *rsa)
{
int bits = BN_num_bits(rsa->n);
@ -335,7 +347,7 @@ int RSA_security_bits(const RSA *rsa)
return 0;
}
#endif
return rsa_compute_security_bits(bits);
return ifc_ffc_compute_security_bits(bits);
}
int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d)

2
crypto/rsa/rsa_local.h
View File

@ -137,8 +137,6 @@ RSA_PRIME_INFO *rsa_multip_info_new(void);
int rsa_multip_calc_product(RSA *rsa);
int rsa_multip_cap(int bits);
uint16_t rsa_compute_security_bits(int n);
int rsa_sp800_56b_validate_strength(int nbits, int strength);
int rsa_check_pminusq_diff(BIGNUM *diff, const BIGNUM *p, const BIGNUM *q,
int nbits);

3
crypto/rsa/rsa_sp800_56b_gen.c
View File

@ -11,6 +11,7 @@
#include <openssl/err.h>
#include <openssl/bn.h>
#include "crypto/bn.h"
#include "crypto/security_bits.h"
#include "rsa_local.h"
#define RSA_FIPS1864_MIN_KEYGEN_KEYSIZE 2048
@ -144,7 +145,7 @@ err:
*/
int rsa_sp800_56b_validate_strength(int nbits, int strength)
{
int s = (int)rsa_compute_security_bits(nbits);
int s = (int)ifc_ffc_compute_security_bits(nbits);
if (s < RSA_FIPS1864_MIN_KEYGEN_STRENGTH
|| s > RSA_FIPS1864_MAX_KEYGEN_STRENGTH) {

39
doc/man3/DH_get0_pqg.pod
View File

@ -37,31 +37,38 @@ L<openssl_user_macros(7)>:
=head1 DESCRIPTION
A DH object contains the parameters B<p>, B<q> and B<g>. Note that the B<q>
parameter is optional. It also contains a public key (B<pub_key>) and
(optionally) a private key (B<priv_key>).
A DH object contains the parameters I<p>, I<q> and I<g>. Note that the I<q>
parameter is optional. It also contains a public key (I<pub_key>) and
(optionally) a private key (I<priv_key>).
The B<p>, B<q> and B<g> parameters can be obtained by calling DH_get0_pqg().
If the parameters have not yet been set then B<*p>, B<*q> and B<*g> will be set
The I<p>, I<q> and I<g> parameters can be obtained by calling DH_get0_pqg().
If the parameters have not yet been set then I<*p>, I<*q> and I<*g> will be set
to NULL. Otherwise they are set to pointers to their respective values. These
point directly to the internal representations of the values and therefore
should not be freed directly.
Any of the out parameters B<p>, B<q>, and B<g> can be NULL, in which case no
Any of the out parameters I<p>, I<q>, and I<g> can be NULL, in which case no
value will be returned for that parameter.
The B<p>, B<q> and B<g> values can be set by calling DH_set0_pqg() and passing
the new values for B<p>, B<q> and B<g> as parameters to the function. Calling
The I<p>, I<q> and I<g> values can be set by calling DH_set0_pqg() and passing
the new values for I<p>, I<q> and I<g> as parameters to the function. Calling
this function transfers the memory management of the values to the DH object,
and therefore the values that have been passed in should not be freed directly
after this function has been called. The B<q> parameter may be NULL.
after this function has been called. The I<q> parameter may be NULL.
DH_set0_pqg() also checks if the parameters associated with I<p> and I<g> and
optionally I<q> are associated with known safe prime groups. If it is a safe
prime group then the value of I<q> will be set to q = (p - 1) / 2 if I<q> is NULL.
For safe prime groups the optional length parameter I<length> is set to twice
the value of the maximum_target_security_strength(BN_num_bits(I<p>)) as listed in
SP800-56Ar3 Table(s) 25 & 26. If it is not a safe prime group then the optional
length parameter will be set if I<q> is not NULL to BN_num_bits(I<q>).
To get the public and private key values use the DH_get0_key() function. A
pointer to the public key will be stored in B<*pub_key>, and a pointer to the
private key will be stored in B<*priv_key>. Either may be NULL if they have not
pointer to the public key will be stored in I<*pub_key>, and a pointer to the
private key will be stored in I<*priv_key>. Either may be NULL if they have not
been set yet, although if the private key has been set then the public key must
be. The values point to the internal representation of the public key and
private key values. This memory should not be freed directly.
Any of the out parameters B<pub_key> and B<priv_key> can be NULL, in which case
Any of the out parameters I<pub_key> and I<priv_key> can be NULL, in which case
no value will be returned for that parameter.
The public and private key values can be set using DH_set0_key(). Either
@ -70,14 +77,14 @@ untouched. As with DH_set0_pqg() this function transfers the memory management
of the key values to the DH object, and therefore they should not be freed
directly after this function has been called.
Any of the values B<p>, B<q>, B<g>, B<priv_key>, and B<pub_key> can also be
Any of the values I<p>, I<q>, I<g>, I<priv_key>, and I<pub_key> can also be
retrieved separately by the corresponding function DH_get0_p(), DH_get0_q(),
DH_get0_g(), DH_get0_priv_key(), and DH_get0_pub_key(), respectively.
DH_set_flags() sets the flags in the B<flags> parameter on the DH object.
DH_set_flags() sets the flags in the I<flags> parameter on the DH object.
Multiple flags can be passed in one go (bitwise ORed together). Any flags that
are already set are left set. DH_test_flags() tests to see whether the flags
passed in the B<flags> parameter are currently set in the DH object. Multiple
passed in the I<flags> parameter are currently set in the DH object. Multiple
flags can be tested in one go. All flags that are currently set are returned, or
zero if none of the flags are set. DH_clear_flags() clears the specified flags
within the DH object.
@ -87,7 +94,7 @@ object, or NULL if no such ENGINE has been set. This function is deprecated.
The DH_get_length() and DH_set_length() functions get and set the optional
length parameter associated with this DH object. If the length is nonzero then
it is used, otherwise it is ignored. The B<length> parameter indicates the
it is used, otherwise it is ignored. The I<length> parameter indicates the
length of the secret exponent (private key) in bits. These functions are
deprecated.

15
doc/man3/DH_new_by_nid.pod
View File

@ -24,15 +24,22 @@ B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>,
B<NID_modp_4096>, B<NID_modp_6144> or B<NID_modp_8192>.
DH_get_nid() determines if the parameters contained in B<dh> match
any named set. It returns the NID corresponding to the matching parameters or
B<NID_undef> if there is no match. This function is deprecated.
any named safe prime group. It returns the NID corresponding to the matching
parameters or B<NID_undef> if there is no match.
Internally it caches the nid, so that any subsequent calls can fetch the
cached value.
If a matching p and g are not found and the value of parameter q is not set,
then it is set to q = (p - 1) / 2.
If parameter q is already set then it must also match the expected q otherwise
no match will be found.
This function is deprecated.
=head1 RETURN VALUES
DH_new_by_nid() returns a set of DH parameters or B<NULL> if an error occurred.
DH_get_nid() returns the NID of the matching set of parameters or
B<NID_undef> if there is no match.
DH_get_nid() returns the NID of the matching set of parameters for p and g
and optionally q, otherwise it returns B<NID_undef> if there is no match.
=head1 HISTORY

15
include/crypto/security_bits.h Normal file
View File

@ -0,0 +1,15 @@
/*
* Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OSSL_SECURITY_BITS_H
# define OSSL_SECURITY_BITS_H
uint16_t ifc_ffc_compute_security_bits(int n);
#endif

71
test/dhtest.c
View File

@ -700,6 +700,7 @@ static int dh_test_prime_groups(int index)
int ok = 0;
DH *dh = NULL;
const BIGNUM *p, *q, *g;
long len;
if (!TEST_ptr(dh = DH_new_by_nid(prime_groups[index])))
goto err;
@ -709,11 +710,80 @@ static int dh_test_prime_groups(int index)
if (!TEST_int_eq(DH_get_nid(dh), prime_groups[index]))
goto err;
len = DH_get_length(dh);
if (!TEST_true(len > 0)
|| !TEST_true(len <= BN_num_bits(q)))
goto err;
ok = 1;
err:
DH_free(dh);
return ok;
}
static int dh_get_nid(void)
{
int ok = 0;
const BIGNUM *p, *q, *g;
BIGNUM *pcpy = NULL, *gcpy = NULL, *qcpy = NULL;
DH *dh1 = DH_new_by_nid(NID_ffdhe2048);
DH *dh2 = DH_new();
if (!TEST_ptr(dh1)
|| !TEST_ptr(dh2))
goto err;
/* Set new DH parameters manually using a existing named group's p & g */
DH_get0_pqg(dh1, &p, &q, &g);
if (!TEST_ptr(p)
|| !TEST_ptr(q)
|| !TEST_ptr(g)
|| !TEST_ptr(pcpy = BN_dup(p))
|| !TEST_ptr(gcpy = BN_dup(g)))
goto err;
if (!TEST_true(DH_set0_pqg(dh2, pcpy, NULL, gcpy)))
goto err;
pcpy = gcpy = NULL;
/* Test q is set if p and g are provided */
if (!TEST_ptr(DH_get0_q(dh2)))
goto err;
/* Test that setting p & g manually returns that it is a named group */
if (!TEST_int_eq(DH_get_nid(dh2), NID_ffdhe2048))
goto err;
/* Test that after changing g it is no longer a named group */
if (!TEST_ptr(gcpy = BN_dup(BN_value_one())))
goto err;
if (!TEST_true(DH_set0_pqg(dh2, NULL, NULL, gcpy)))
goto err;
gcpy = NULL;
if (!TEST_int_eq(DH_get_nid(dh2), NID_undef))
goto err;
/* Test that setting an incorrect q results in this not being a named group */
if (!TEST_ptr(pcpy = BN_dup(p))
|| !TEST_ptr(qcpy = BN_dup(q))
|| !TEST_ptr(gcpy = BN_dup(g))
|| !TEST_int_eq(BN_add_word(qcpy, 2), 1)
|| !TEST_true(DH_set0_pqg(dh2, pcpy, qcpy, gcpy)))
goto err;
pcpy = qcpy = gcpy = NULL;
if (!TEST_int_eq(DH_get_nid(dh2), NID_undef))
goto err;
ok = 1;
err:
BN_free(pcpy);
BN_free(qcpy);
BN_free(gcpy);
DH_free(dh2);
DH_free(dh1);
return ok;
}
#endif
@ -726,6 +796,7 @@ int setup_tests(void)
ADD_TEST(rfc5114_test);
ADD_TEST(rfc7919_test);
ADD_ALL_TESTS(dh_test_prime_groups, OSSL_NELEM(prime_groups));
ADD_TEST(dh_get_nid);
#endif
return 1;
}