postgresql/contrib/pgcrypto/openssl.c
Daniel Gustafsson 318df80235 Disable OpenSSL EVP digest padding in pgcrypto
The PX layer in pgcrypto is handling digest padding on its own uniformly
for all backend implementations. Starting with OpenSSL 3.0.0, DecryptUpdate
doesn't flush the last block in case padding is enabled so explicitly
disable it as we don't use it.

This will be backpatched to all supported version once there is sufficient
testing in the buildfarm of OpenSSL 3.

Reviewed-by: Peter Eisentraut, Michael Paquier
Discussion: https://postgr.es/m/FEF81714-D479-4512-839B-C769D2605F8A@yesql.se
2021-08-10 15:01:52 +02:00

822 lines
17 KiB
C

/*
* openssl.c
* Wrapper for OpenSSL library.
*
* Copyright (c) 2001 Marko Kreen
* All rights reserved.
*
* 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, this list of conditions and the following disclaimer.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 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 ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* contrib/pgcrypto/openssl.c
*/
#include "postgres.h"
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#include "px.h"
#include "utils/memutils.h"
#include "utils/resowner.h"
/*
* Max lengths we might want to handle.
*/
#define MAX_KEY (512/8)
#define MAX_IV (128/8)
/*
* Hashes
*/
/*
* To make sure we don't leak OpenSSL handles on abort, we keep OSSLDigest
* objects in a linked list, allocated in TopMemoryContext. We use the
* ResourceOwner mechanism to free them on abort.
*/
typedef struct OSSLDigest
{
const EVP_MD *algo;
EVP_MD_CTX *ctx;
ResourceOwner owner;
struct OSSLDigest *next;
struct OSSLDigest *prev;
} OSSLDigest;
static OSSLDigest *open_digests = NULL;
static bool digest_resowner_callback_registered = false;
static void
free_openssl_digest(OSSLDigest *digest)
{
EVP_MD_CTX_destroy(digest->ctx);
if (digest->prev)
digest->prev->next = digest->next;
else
open_digests = digest->next;
if (digest->next)
digest->next->prev = digest->prev;
pfree(digest);
}
/*
* Close any open OpenSSL handles on abort.
*/
static void
digest_free_callback(ResourceReleasePhase phase,
bool isCommit,
bool isTopLevel,
void *arg)
{
OSSLDigest *curr;
OSSLDigest *next;
if (phase != RESOURCE_RELEASE_AFTER_LOCKS)
return;
next = open_digests;
while (next)
{
curr = next;
next = curr->next;
if (curr->owner == CurrentResourceOwner)
{
if (isCommit)
elog(WARNING, "pgcrypto digest reference leak: digest %p still referenced", curr);
free_openssl_digest(curr);
}
}
}
static unsigned
digest_result_size(PX_MD *h)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
int result = EVP_MD_CTX_size(digest->ctx);
if (result < 0)
elog(ERROR, "EVP_MD_CTX_size() failed");
return result;
}
static unsigned
digest_block_size(PX_MD *h)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
int result = EVP_MD_CTX_block_size(digest->ctx);
if (result < 0)
elog(ERROR, "EVP_MD_CTX_block_size() failed");
return result;
}
static void
digest_reset(PX_MD *h)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
if (!EVP_DigestInit_ex(digest->ctx, digest->algo, NULL))
elog(ERROR, "EVP_DigestInit_ex() failed");
}
static void
digest_update(PX_MD *h, const uint8 *data, unsigned dlen)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
if (!EVP_DigestUpdate(digest->ctx, data, dlen))
elog(ERROR, "EVP_DigestUpdate() failed");
}
static void
digest_finish(PX_MD *h, uint8 *dst)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
if (!EVP_DigestFinal_ex(digest->ctx, dst, NULL))
elog(ERROR, "EVP_DigestFinal_ex() failed");
}
static void
digest_free(PX_MD *h)
{
OSSLDigest *digest = (OSSLDigest *) h->p.ptr;
free_openssl_digest(digest);
pfree(h);
}
static int px_openssl_initialized = 0;
/* PUBLIC functions */
int
px_find_digest(const char *name, PX_MD **res)
{
const EVP_MD *md;
EVP_MD_CTX *ctx;
PX_MD *h;
OSSLDigest *digest;
if (!px_openssl_initialized)
{
px_openssl_initialized = 1;
OpenSSL_add_all_algorithms();
}
if (!digest_resowner_callback_registered)
{
RegisterResourceReleaseCallback(digest_free_callback, NULL);
digest_resowner_callback_registered = true;
}
md = EVP_get_digestbyname(name);
if (md == NULL)
return PXE_NO_HASH;
/*
* Create an OSSLDigest object, an OpenSSL MD object, and a PX_MD object.
* The order is crucial, to make sure we don't leak anything on
* out-of-memory or other error.
*/
digest = MemoryContextAlloc(TopMemoryContext, sizeof(*digest));
ctx = EVP_MD_CTX_create();
if (!ctx)
{
pfree(digest);
return -1;
}
if (EVP_DigestInit_ex(ctx, md, NULL) == 0)
{
EVP_MD_CTX_destroy(ctx);
pfree(digest);
return -1;
}
digest->algo = md;
digest->ctx = ctx;
digest->owner = CurrentResourceOwner;
digest->next = open_digests;
digest->prev = NULL;
open_digests = digest;
/* The PX_MD object is allocated in the current memory context. */
h = palloc(sizeof(*h));
h->result_size = digest_result_size;
h->block_size = digest_block_size;
h->reset = digest_reset;
h->update = digest_update;
h->finish = digest_finish;
h->free = digest_free;
h->p.ptr = (void *) digest;
*res = h;
return 0;
}
/*
* Ciphers
*
* We use OpenSSL's EVP* family of functions for these.
*/
/*
* prototype for the EVP functions that return an algorithm, e.g.
* EVP_aes_128_cbc().
*/
typedef const EVP_CIPHER *(*ossl_EVP_cipher_func) (void);
/*
* ossl_cipher contains the static information about each cipher.
*/
struct ossl_cipher
{
int (*init) (PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv);
ossl_EVP_cipher_func cipher_func;
int block_size;
int max_key_size;
};
/*
* OSSLCipher contains the state for using a cipher. A separate OSSLCipher
* object is allocated in each px_find_cipher() call.
*
* To make sure we don't leak OpenSSL handles on abort, we keep OSSLCipher
* objects in a linked list, allocated in TopMemoryContext. We use the
* ResourceOwner mechanism to free them on abort.
*/
typedef struct OSSLCipher
{
EVP_CIPHER_CTX *evp_ctx;
const EVP_CIPHER *evp_ciph;
uint8 key[MAX_KEY];
uint8 iv[MAX_IV];
unsigned klen;
unsigned init;
const struct ossl_cipher *ciph;
ResourceOwner owner;
struct OSSLCipher *next;
struct OSSLCipher *prev;
} OSSLCipher;
static OSSLCipher *open_ciphers = NULL;
static bool cipher_resowner_callback_registered = false;
static void
free_openssl_cipher(OSSLCipher *od)
{
EVP_CIPHER_CTX_free(od->evp_ctx);
if (od->prev)
od->prev->next = od->next;
else
open_ciphers = od->next;
if (od->next)
od->next->prev = od->prev;
pfree(od);
}
/*
* Close any open OpenSSL cipher handles on abort.
*/
static void
cipher_free_callback(ResourceReleasePhase phase,
bool isCommit,
bool isTopLevel,
void *arg)
{
OSSLCipher *curr;
OSSLCipher *next;
if (phase != RESOURCE_RELEASE_AFTER_LOCKS)
return;
next = open_ciphers;
while (next)
{
curr = next;
next = curr->next;
if (curr->owner == CurrentResourceOwner)
{
if (isCommit)
elog(WARNING, "pgcrypto cipher reference leak: cipher %p still referenced", curr);
free_openssl_cipher(curr);
}
}
}
/* Common routines for all algorithms */
static unsigned
gen_ossl_block_size(PX_Cipher *c)
{
OSSLCipher *od = (OSSLCipher *) c->ptr;
return od->ciph->block_size;
}
static unsigned
gen_ossl_key_size(PX_Cipher *c)
{
OSSLCipher *od = (OSSLCipher *) c->ptr;
return od->ciph->max_key_size;
}
static unsigned
gen_ossl_iv_size(PX_Cipher *c)
{
unsigned ivlen;
OSSLCipher *od = (OSSLCipher *) c->ptr;
ivlen = od->ciph->block_size;
return ivlen;
}
static void
gen_ossl_free(PX_Cipher *c)
{
OSSLCipher *od = (OSSLCipher *) c->ptr;
free_openssl_cipher(od);
pfree(c);
}
static int
gen_ossl_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
uint8 *res)
{
OSSLCipher *od = c->ptr;
int outlen;
if (!od->init)
{
if (!EVP_DecryptInit_ex(od->evp_ctx, od->evp_ciph, NULL, NULL, NULL))
return PXE_CIPHER_INIT;
if (!EVP_CIPHER_CTX_set_padding(od->evp_ctx, 0))
return PXE_CIPHER_INIT;
if (!EVP_CIPHER_CTX_set_key_length(od->evp_ctx, od->klen))
return PXE_CIPHER_INIT;
if (!EVP_DecryptInit_ex(od->evp_ctx, NULL, NULL, od->key, od->iv))
return PXE_CIPHER_INIT;
od->init = true;
}
if (!EVP_DecryptUpdate(od->evp_ctx, res, &outlen, data, dlen))
return PXE_DECRYPT_FAILED;
return 0;
}
static int
gen_ossl_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
uint8 *res)
{
OSSLCipher *od = c->ptr;
int outlen;
if (!od->init)
{
if (!EVP_EncryptInit_ex(od->evp_ctx, od->evp_ciph, NULL, NULL, NULL))
return PXE_CIPHER_INIT;
if (!EVP_CIPHER_CTX_set_padding(od->evp_ctx, 0))
return PXE_CIPHER_INIT;
if (!EVP_CIPHER_CTX_set_key_length(od->evp_ctx, od->klen))
return PXE_CIPHER_INIT;
if (!EVP_EncryptInit_ex(od->evp_ctx, NULL, NULL, od->key, od->iv))
return PXE_CIPHER_INIT;
od->init = true;
}
if (!EVP_EncryptUpdate(od->evp_ctx, res, &outlen, data, dlen))
return PXE_ENCRYPT_FAILED;
return 0;
}
/* Blowfish */
/*
* Check if strong crypto is supported. Some OpenSSL installations
* support only short keys and unfortunately BF_set_key does not return any
* error value. This function tests if is possible to use strong key.
*/
static int
bf_check_supported_key_len(void)
{
static const uint8 key[56] = {
0xf0, 0xe1, 0xd2, 0xc3, 0xb4, 0xa5, 0x96, 0x87, 0x78, 0x69,
0x5a, 0x4b, 0x3c, 0x2d, 0x1e, 0x0f, 0x00, 0x11, 0x22, 0x33,
0x44, 0x55, 0x66, 0x77, 0x04, 0x68, 0x91, 0x04, 0xc2, 0xfd,
0x3b, 0x2f, 0x58, 0x40, 0x23, 0x64, 0x1a, 0xba, 0x61, 0x76,
0x1f, 0x1f, 0x1f, 0x1f, 0x0e, 0x0e, 0x0e, 0x0e, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};
static const uint8 data[8] = {0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10};
static const uint8 res[8] = {0xc0, 0x45, 0x04, 0x01, 0x2e, 0x4e, 0x1f, 0x53};
uint8 out[8];
EVP_CIPHER_CTX *evp_ctx;
int outlen;
int status = 0;
/* encrypt with 448bits key and verify output */
evp_ctx = EVP_CIPHER_CTX_new();
if (!evp_ctx)
return 0;
if (!EVP_EncryptInit_ex(evp_ctx, EVP_bf_ecb(), NULL, NULL, NULL))
goto leave;
if (!EVP_CIPHER_CTX_set_key_length(evp_ctx, 56))
goto leave;
if (!EVP_EncryptInit_ex(evp_ctx, NULL, NULL, key, NULL))
goto leave;
if (!EVP_EncryptUpdate(evp_ctx, out, &outlen, data, 8))
goto leave;
if (memcmp(out, res, 8) != 0)
goto leave; /* Output does not match -> strong cipher is
* not supported */
status = 1;
leave:
EVP_CIPHER_CTX_free(evp_ctx);
return status;
}
static int
bf_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
unsigned bs = gen_ossl_block_size(c);
static int bf_is_strong = -1;
/*
* Test if key len is supported. BF_set_key silently cut large keys and it
* could be a problem when user transfer crypted data from one server to
* another.
*/
if (bf_is_strong == -1)
bf_is_strong = bf_check_supported_key_len();
if (!bf_is_strong && klen > 16)
return PXE_KEY_TOO_BIG;
/* Key len is supported. We can use it. */
od->klen = klen;
memcpy(od->key, key, klen);
if (iv)
memcpy(od->iv, iv, bs);
else
memset(od->iv, 0, bs);
return 0;
}
/* DES */
static int
ossl_des_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
unsigned bs = gen_ossl_block_size(c);
od->klen = 8;
memset(od->key, 0, 8);
memcpy(od->key, key, klen > 8 ? 8 : klen);
if (iv)
memcpy(od->iv, iv, bs);
else
memset(od->iv, 0, bs);
return 0;
}
/* DES3 */
static int
ossl_des3_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
unsigned bs = gen_ossl_block_size(c);
od->klen = 24;
memset(od->key, 0, 24);
memcpy(od->key, key, klen > 24 ? 24 : klen);
if (iv)
memcpy(od->iv, iv, bs);
else
memset(od->iv, 0, bs);
return 0;
}
/* CAST5 */
static int
ossl_cast_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
unsigned bs = gen_ossl_block_size(c);
od->klen = klen;
memcpy(od->key, key, klen);
if (iv)
memcpy(od->iv, iv, bs);
else
memset(od->iv, 0, bs);
return 0;
}
/* AES */
static int
ossl_aes_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
unsigned bs = gen_ossl_block_size(c);
if (klen <= 128 / 8)
od->klen = 128 / 8;
else if (klen <= 192 / 8)
od->klen = 192 / 8;
else if (klen <= 256 / 8)
od->klen = 256 / 8;
else
return PXE_KEY_TOO_BIG;
memcpy(od->key, key, klen);
if (iv)
memcpy(od->iv, iv, bs);
else
memset(od->iv, 0, bs);
return 0;
}
static int
ossl_aes_ecb_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
int err;
err = ossl_aes_init(c, key, klen, iv);
if (err)
return err;
switch (od->klen)
{
case 128 / 8:
od->evp_ciph = EVP_aes_128_ecb();
break;
case 192 / 8:
od->evp_ciph = EVP_aes_192_ecb();
break;
case 256 / 8:
od->evp_ciph = EVP_aes_256_ecb();
break;
default:
/* shouldn't happen */
err = PXE_CIPHER_INIT;
break;
}
return err;
}
static int
ossl_aes_cbc_init(PX_Cipher *c, const uint8 *key, unsigned klen, const uint8 *iv)
{
OSSLCipher *od = c->ptr;
int err;
err = ossl_aes_init(c, key, klen, iv);
if (err)
return err;
switch (od->klen)
{
case 128 / 8:
od->evp_ciph = EVP_aes_128_cbc();
break;
case 192 / 8:
od->evp_ciph = EVP_aes_192_cbc();
break;
case 256 / 8:
od->evp_ciph = EVP_aes_256_cbc();
break;
default:
/* shouldn't happen */
err = PXE_CIPHER_INIT;
break;
}
return err;
}
/*
* aliases
*/
static PX_Alias ossl_aliases[] = {
{"bf", "bf-cbc"},
{"blowfish", "bf-cbc"},
{"blowfish-cbc", "bf-cbc"},
{"blowfish-ecb", "bf-ecb"},
{"blowfish-cfb", "bf-cfb"},
{"des", "des-cbc"},
{"3des", "des3-cbc"},
{"3des-ecb", "des3-ecb"},
{"3des-cbc", "des3-cbc"},
{"cast5", "cast5-cbc"},
{"aes", "aes-cbc"},
{"rijndael", "aes-cbc"},
{"rijndael-cbc", "aes-cbc"},
{"rijndael-ecb", "aes-ecb"},
{NULL}
};
static const struct ossl_cipher ossl_bf_cbc = {
bf_init,
EVP_bf_cbc,
64 / 8, 448 / 8
};
static const struct ossl_cipher ossl_bf_ecb = {
bf_init,
EVP_bf_ecb,
64 / 8, 448 / 8
};
static const struct ossl_cipher ossl_bf_cfb = {
bf_init,
EVP_bf_cfb,
64 / 8, 448 / 8
};
static const struct ossl_cipher ossl_des_ecb = {
ossl_des_init,
EVP_des_ecb,
64 / 8, 64 / 8
};
static const struct ossl_cipher ossl_des_cbc = {
ossl_des_init,
EVP_des_cbc,
64 / 8, 64 / 8
};
static const struct ossl_cipher ossl_des3_ecb = {
ossl_des3_init,
EVP_des_ede3_ecb,
64 / 8, 192 / 8
};
static const struct ossl_cipher ossl_des3_cbc = {
ossl_des3_init,
EVP_des_ede3_cbc,
64 / 8, 192 / 8
};
static const struct ossl_cipher ossl_cast_ecb = {
ossl_cast_init,
EVP_cast5_ecb,
64 / 8, 128 / 8
};
static const struct ossl_cipher ossl_cast_cbc = {
ossl_cast_init,
EVP_cast5_cbc,
64 / 8, 128 / 8
};
static const struct ossl_cipher ossl_aes_ecb = {
ossl_aes_ecb_init,
NULL, /* EVP_aes_XXX_ecb(), determined in init
* function */
128 / 8, 256 / 8
};
static const struct ossl_cipher ossl_aes_cbc = {
ossl_aes_cbc_init,
NULL, /* EVP_aes_XXX_cbc(), determined in init
* function */
128 / 8, 256 / 8
};
/*
* Special handlers
*/
struct ossl_cipher_lookup
{
const char *name;
const struct ossl_cipher *ciph;
};
static const struct ossl_cipher_lookup ossl_cipher_types[] = {
{"bf-cbc", &ossl_bf_cbc},
{"bf-ecb", &ossl_bf_ecb},
{"bf-cfb", &ossl_bf_cfb},
{"des-ecb", &ossl_des_ecb},
{"des-cbc", &ossl_des_cbc},
{"des3-ecb", &ossl_des3_ecb},
{"des3-cbc", &ossl_des3_cbc},
{"cast5-ecb", &ossl_cast_ecb},
{"cast5-cbc", &ossl_cast_cbc},
{"aes-ecb", &ossl_aes_ecb},
{"aes-cbc", &ossl_aes_cbc},
{NULL}
};
/* PUBLIC functions */
int
px_find_cipher(const char *name, PX_Cipher **res)
{
const struct ossl_cipher_lookup *i;
PX_Cipher *c = NULL;
EVP_CIPHER_CTX *ctx;
OSSLCipher *od;
name = px_resolve_alias(ossl_aliases, name);
for (i = ossl_cipher_types; i->name; i++)
if (strcmp(i->name, name) == 0)
break;
if (i->name == NULL)
return PXE_NO_CIPHER;
if (!cipher_resowner_callback_registered)
{
RegisterResourceReleaseCallback(cipher_free_callback, NULL);
cipher_resowner_callback_registered = true;
}
/*
* Create an OSSLCipher object, an EVP_CIPHER_CTX object and a PX_Cipher.
* The order is crucial, to make sure we don't leak anything on
* out-of-memory or other error.
*/
od = MemoryContextAllocZero(TopMemoryContext, sizeof(*od));
od->ciph = i->ciph;
/* Allocate an EVP_CIPHER_CTX object. */
ctx = EVP_CIPHER_CTX_new();
if (!ctx)
{
pfree(od);
return PXE_CIPHER_INIT;
}
od->evp_ctx = ctx;
od->owner = CurrentResourceOwner;
od->next = open_ciphers;
od->prev = NULL;
open_ciphers = od;
if (i->ciph->cipher_func)
od->evp_ciph = i->ciph->cipher_func();
/* The PX_Cipher is allocated in current memory context */
c = palloc(sizeof(*c));
c->block_size = gen_ossl_block_size;
c->key_size = gen_ossl_key_size;
c->iv_size = gen_ossl_iv_size;
c->free = gen_ossl_free;
c->init = od->ciph->init;
c->encrypt = gen_ossl_encrypt;
c->decrypt = gen_ossl_decrypt;
c->ptr = od;
*res = c;
return 0;
}