Proxmox-Port/libtpms
1
0
Fork 0
mirror of https://github.com/stefanberger/libtpms synced 2026-01-24 08:30:34 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

tpm2: Implement a cache for the private exponent D and prime Q

Browse Source 
Implement a cache for the private exponent 'D' and prime 'Q' so that we
do not have to recalculate 'Q' and 'D' every time an RSA key is used. For
a cache hit we now use ~34000 cycles and on a cache miss it needs around
130000 cycles. Previously it needed around 100000 cycles to calcuate 'Q'
and 'D'. Assuming that keys will be reused and the cache is big enough
for the number of keys being use (64 entries), it seems well worth it.

This solution is better than extending the OBJECT with 'D' since OBJECT is
kept in the TPM's NVRAM and we would then need more memory to store OBJECTs
there.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
This commit is contained in:
Stefan Berger 2021-02-25 14:05:28 -05:00 committed by Stefan Berger
parent 23b27060b6
commit fdb9ad3b73
5 changed files with 299 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/Makefile.am
View File

@ -535,6 +535,7 @@ libtpms_tpm2_la_SOURCES += \
tpm2/crypto/openssl/CryptRsa.c \
tpm2/crypto/openssl/CryptSmac.c \
tpm2/crypto/openssl/CryptSym.c \
tpm2/crypto/openssl/ExpDCache.c \
tpm2/crypto/openssl/Helpers.c \
tpm2/crypto/openssl/TpmToOsslDesSupport.c \
tpm2/crypto/openssl/TpmToOsslMath.c \
@ -546,6 +547,7 @@ noinst_HEADERS += \
tpm2/crypto/openssl/BnMath_fp.h \
tpm2/crypto/openssl/BnMemory_fp.h \
tpm2/crypto/openssl/BnValues.h \
tpm2/crypto/openssl/ExpDCache_fp.h \
tpm2/crypto/openssl/Helpers_fp.h \
tpm2/crypto/openssl/LibSupport.h \
tpm2/crypto/openssl/TpmToOsslDesSupport_fp.h \

200
src/tpm2/crypto/openssl/ExpDCache.c Normal file
View File

@ -0,0 +1,200 @@
/********************************************************************************/
/* */
/* Private Exponent D cache functions */
/* Written by Stefan Berger */
/* IBM Thomas J. Watson Research Center */
/* */
/* Licenses and Notices */
/* */
/* 1. Copyright Licenses: */
/* */
/* - Trusted Computing Group (TCG) grants to the user of the source code in */
/* this specification (the "Source Code") a worldwide, irrevocable, */
/* nonexclusive, royalty free, copyright license to reproduce, create */
/* derivative works, distribute, display and perform the Source Code and */
/* derivative works thereof, and to grant others the rights granted herein. */
/* */
/* - The TCG grants to the user of the other parts of the specification */
/* (other than the Source Code) the rights to reproduce, distribute, */
/* display, and perform the specification solely for the purpose of */
/* developing products based on such documents. */
/* */
/* 2. Source Code Distribution Conditions: */
/* */
/* - Redistributions of Source Code must retain the above copyright licenses, */
/* this list of conditions and the following disclaimers. */
/* */
/* - Redistributions in binary form must reproduce the above copyright */
/* licenses, this list of conditions and the following disclaimers in the */
/* documentation and/or other materials provided with the distribution. */
/* */
/* 3. Disclaimers: */
/* */
/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */
/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */
/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */
/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */
/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */
/* information on specification licensing rights available through TCG */
/* membership agreements. */
/* */
/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */
/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */
/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */
/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */
/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */
/* */
/* - Without limitation, TCG and its members and licensors disclaim all */
/* liability, including liability for infringement of any proprietary */
/* rights, relating to use of information in this specification and to the */
/* implementation of this specification, and TCG disclaims all liability for */
/* cost of procurement of substitute goods or services, lost profits, loss */
/* of use, loss of data or any incidental, consequential, direct, indirect, */
/* or special damages, whether under contract, tort, warranty or otherwise, */
/* arising in any way out of use or reliance upon this specification or any */
/* information herein. */
/* */
/* (c) Copyright IBM Corp., 2021 */
/* */
/********************************************************************************/
#include "Tpm.h"
#include "ExpDCache_fp.h"
/* Implement a cache for the private exponent D so it doesn't need to be
* recalculated every time from P, Q, E and N (modulus). The cache has a
* number of entries that cache D and use P, Q, and E for lookup.
* A least-recently-used cache eviction strategy is implemented that evicts
* the oldest cache entry in case space is needed. An entry is young once
* it is added or made young when it was found via lookup. All other entries
* age by '1' when an entry is added or accessed.
*/
struct ExpDCacheEntry {
/* The age of the entry; the higher the number the more likely it
* will be evicted soon
*/
unsigned int age;
BIGNUM *P; /* input */
BIGNUM *N; /* input */
BIGNUM *E; /* input */
BIGNUM *Q; /* cached */
BIGNUM *D; /* cached */
};
#define DCACHE_NUM_ENTRIES 64
static struct ExpDCacheEntry ExpDCache[DCACHE_NUM_ENTRIES];
/* Increment the age of all cache entries that have a current age <= maxage */
static void ExpDCacheIncrementAge(unsigned maxage)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(ExpDCache); i++) {
if (ExpDCache[i].age <= maxage && ExpDCache[i].D != NULL)
ExpDCache[i].age++;
}
}
/* Free the data associated with a ExpDCacheEntry and initialize it */
static void ExpDCacheEntryFree(struct ExpDCacheEntry *dce)
{
BN_clear_free(dce->P);
BN_free(dce->N);
BN_free(dce->E);
BN_clear_free(dce->Q);
BN_clear_free(dce->D);
memset(dce, 0, sizeof(*dce));
}
void ExpDCacheFree(void)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(ExpDCache); i++)
ExpDCacheEntryFree(&ExpDCache[i]);
}
/* Get a ExpDCacheEntry by finding either an unused entry or evicting the oldest
* entry. The returned entry will have all NULL pointers and age 0.
*/
static struct ExpDCacheEntry *ExpDCacheEntryGet(void)
{
size_t i, use_i = 0;
unsigned oldest_age = 0;
struct ExpDCacheEntry *dce;
for (i = 0; i < ARRAY_SIZE(ExpDCache); i++) {
if (ExpDCache[i].D == NULL) {
/* use this free entry */
use_i = i;
break;
}
if (ExpDCache[i].age > oldest_age) {
/* this one is currently the oldest */
use_i = i;
oldest_age = ExpDCache[i].age;
}
}
dce = &ExpDCache[use_i];
ExpDCacheEntryFree(dce);
return dce;
}
/* Add 'D' to the ExpDCache. This function does not check for duplicates */
void ExpDCacheAdd(const BIGNUM *P, const BIGNUM *N, const BIGNUM *E,
const BIGNUM *Q, const BIGNUM *D)
{
struct ExpDCacheEntry *dce = ExpDCacheEntryGet();
/* age of 'dce' is '0' */
dce->P = BN_dup(P);
dce->N = BN_dup(N);
dce->E = BN_dup(E);
dce->Q = BN_dup(Q);
dce->D = BN_dup(D);
if (!dce->P || !dce->N || !dce->E || !dce->Q || !dce->D)
ExpDCacheEntryFree(dce);
else
ExpDCacheIncrementAge(~0);
}
BIGNUM *ExpDCacheFind(const BIGNUM *P, const BIGNUM *N, const BIGNUM *E, BIGNUM **Q)
{
size_t i;
unsigned myage;
BIGNUM *D;
for (i = 0; i < ARRAY_SIZE(ExpDCache); i++) {
if (BN_cmp(ExpDCache[i].P, P) == 0 && BN_cmp(ExpDCache[i].N, N) == 0 &&
BN_cmp(ExpDCache[i].E, E) == 0) {
/* entry found */
myage = ExpDCache[i].age;
/* mark this entry as most recently used */
ExpDCache[i].age = 0;
/* Increment everyone who is <= 'myage'.
* The age of this entry will be '1' after that.
*/
ExpDCacheIncrementAge(myage);
*Q = BN_dup(ExpDCache[i].Q);
if (*Q == NULL)
return NULL;
D = BN_dup(ExpDCache[i].D);
if (D == NULL) {
BN_clear_free(*Q);
*Q = NULL;
return NULL;
}
BN_set_flags(*Q, BN_FLG_CONSTTIME);
BN_set_flags(D, BN_FLG_CONSTTIME);
return D;
}
}
return NULL;
}

75
src/tpm2/crypto/openssl/ExpDCache_fp.h Normal file
View File

@ -0,0 +1,75 @@
/********************************************************************************/
/* */
/* Private Exponent D cache functions */
/* Written by Stefan Berger */
/* IBM Thomas J. Watson Research Center */
/* */
/* Licenses and Notices */
/* */
/* 1. Copyright Licenses: */
/* */
/* - Trusted Computing Group (TCG) grants to the user of the source code in */
/* this specification (the "Source Code") a worldwide, irrevocable, */
/* nonexclusive, royalty free, copyright license to reproduce, create */
/* derivative works, distribute, display and perform the Source Code and */
/* derivative works thereof, and to grant others the rights granted herein. */
/* */
/* - The TCG grants to the user of the other parts of the specification */
/* (other than the Source Code) the rights to reproduce, distribute, */
/* display, and perform the specification solely for the purpose of */
/* developing products based on such documents. */
/* */
/* 2. Source Code Distribution Conditions: */
/* */
/* - Redistributions of Source Code must retain the above copyright licenses, */
/* this list of conditions and the following disclaimers. */
/* */
/* - Redistributions in binary form must reproduce the above copyright */
/* licenses, this list of conditions and the following disclaimers in the */
/* documentation and/or other materials provided with the distribution. */
/* */
/* 3. Disclaimers: */
/* */
/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */
/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */
/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */
/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */
/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */
/* information on specification licensing rights available through TCG */
/* membership agreements. */
/* */
/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */
/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */
/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */
/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */
/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */
/* */
/* - Without limitation, TCG and its members and licensors disclaim all */
/* liability, including liability for infringement of any proprietary */
/* rights, relating to use of information in this specification and to the */
/* implementation of this specification, and TCG disclaims all liability for */
/* cost of procurement of substitute goods or services, lost profits, loss */
/* of use, loss of data or any incidental, consequential, direct, indirect, */
/* or special damages, whether under contract, tort, warranty or otherwise, */
/* arising in any way out of use or reliance upon this specification or any */
/* information herein. */
/* */
/* (c) Copyright IBM Corp., 2021 */
/* */
/********************************************************************************/
#ifndef DCACHE_FP_H
#define DCACHE_FP_H
#include <openssl/bn.h>
BIGNUM *ExpDCacheFind(const BIGNUM *P, const BIGNUM *N, const BIGNUM *E,
BIGNUM **Q);
void ExpDCacheAdd(const BIGNUM *P, const BIGNUM *N, const BIGNUM *E,
const BIGNUM *Q, const BIGNUM *D);
void ExpDCacheFree(void);
#endif /* DCACHE_FP_H */

33
src/tpm2/crypto/openssl/Helpers.c
View File

@ -59,6 +59,7 @@
/********************************************************************************/
#include "Tpm.h"
#include "ExpDCache_fp.h"
#include "Helpers_fp.h"
#include "TpmToOsslMath_fp.h"
@ -501,12 +502,9 @@ InitOpenSSLRSAPrivateKey(OBJECT *rsaKey, // IN
if(!rsaKey->attributes.privateExp)
CryptRsaLoadPrivateExponent(rsaKey);
ctx = BN_CTX_new();
Q = BN_new();
Qr = BN_new();
P = BN_bin2bn(rsaKey->sensitive.sensitive.rsa.t.buffer,
rsaKey->sensitive.sensitive.rsa.t.size, NULL);
if (ctx == NULL || Q == NULL || Qr == NULL || P == NULL)
if (P == NULL)
ERROR_RETURN(TPM_RC_FAILURE)
key = EVP_PKEY_get0_RSA(*pkey);
@ -514,16 +512,25 @@ InitOpenSSLRSAPrivateKey(OBJECT *rsaKey, // IN
ERROR_RETURN(TPM_RC_FAILURE);
RSA_get0_key(key, &N, &E, NULL);
/* Q = N/P; no remainder */
BN_set_flags(P, BN_FLG_CONSTTIME); // P is secret
BN_div(Q, Qr, N, P, ctx);
if(!BN_is_zero(Qr))
ERROR_RETURN(TPM_RC_BINDING);
BN_set_flags(Q, BN_FLG_CONSTTIME); // Q is secret
D = ExpDCacheFind(P, N, E, &Q);
if (D == NULL) {
ctx = BN_CTX_new();
Q = BN_new();
Qr = BN_new();
if (ctx == NULL || Q == NULL || Qr == NULL)
ERROR_RETURN(TPM_RC_FAILURE);
/* Q = N/P; no remainder */
BN_set_flags(P, BN_FLG_CONSTTIME); // P is secret
BN_div(Q, Qr, N, P, ctx);
if(!BN_is_zero(Qr))
ERROR_RETURN(TPM_RC_BINDING);
BN_set_flags(Q, BN_FLG_CONSTTIME); // Q is secret
// TODO(stefanb): consider caching D in the OBJECT
if (ComputePrivateExponentD(P, Q, E, N, &D) == FALSE ||
RSA_set0_key(key, NULL, NULL, D) != 1)
if (ComputePrivateExponentD(P, Q, E, N, &D) == FALSE)
ERROR_RETURN(TPM_RC_FAILURE);
ExpDCacheAdd(P, N, E, Q, D);
}
if (RSA_set0_key(key, NULL, NULL, D) != 1)
ERROR_RETURN(TPM_RC_FAILURE);
DoRSACheckKey(P, Q, N, E, D);

2
src/tpm_tpm2_interface.c
View File

@ -59,6 +59,7 @@
#include "tpm2/PlatformACT.h"
#include "tpm2/PlatformData.h"
#include "tpm2/Volatile.h"
#include "tpm2/crypto/openssl/ExpDCache_fp.h"
#define TPM_HAVE_TPM2_DECLARATIONS
#include "tpm12/tpm_nvfile.h" // TPM_NVRAM_Loaddata()
@ -169,6 +170,7 @@ static void TPM2_Terminate(void)
TPM_TearDown();
_rpc__Signal_PowerOff();
ExpDCacheFree();
}
static TPM_RESULT TPM2_Process(unsigned char **respbuffer, uint32_t *resp_size,