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8c35e96b6054efc724156658cc46288ce3cc421d
NetworkManager/libnm-util/crypto_nss.c
Dan Williams 8c35e96b60 libnm-util: add nm_utils_rsa_key_encrypt() and fix crypto padding mixups 
To be backwards compatible clients need to handle both paths to private
keys and the decrypted private key data, which is what used to get passed
in the private-key and phase2-private-key attributes of the 802.1x setting.
When moving a connection around between system-settings and user-settings,
if the private key is decrypted data, the settings service needs to store
that decrypted data somewhere so that the key can be sent to NM during
the connection process.

But we don't want to store the decrypted private key data, so we have to
re-encrypt it (possibly generating a private key password if one wasn't
sent with the decrypted data) and save it to disk, then send NM a path
to that private key during connection.

To help clients do this, and so that they don't have to carry around
multiple crypto implementations depending on whether they want to use
NSS or gnutls/gcrypt, add a helper to libnm-util.

Furthermore, I misunderstood a bunch of stuff with crypto padding when
writing the encrypt/decrypt functions long ago, so fix that up.  Don't
return padding as part of the decrypted data, and make sure to verify
the padding's expected lengths and values when decrypting.  Many thanks
to Nalin Dahyabhai for pointing me in the right direction.
2009-09-15 16:01:50 -07:00

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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/*
* Dan Williams <dcbw@redhat.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
*
* (C) Copyright 2007 - 2009 Red Hat, Inc.
*/
#include "config.h"
#include <glib.h>
#include <glib/gi18n.h>
#include <prinit.h>
#include <nss.h>
#include <pk11pub.h>
#include <pkcs11t.h>
#include <cert.h>
#include <prerror.h>
#include <p12.h>
#include <ciferfam.h>
#include <p12plcy.h>
#include "crypto.h"
static gboolean initialized = FALSE;
gboolean
crypto_init (GError **error)
{
SECStatus ret;
if (initialized)
return TRUE;
PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 1);
ret = NSS_NoDB_Init (NULL);
if (ret != SECSuccess) {
PR_Cleanup ();
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_INIT_FAILED,
_("Failed to initialize the crypto engine: %d."),
PR_GetError ());
return FALSE;
}
SEC_PKCS12EnableCipher(PKCS12_RC4_40, 1);
SEC_PKCS12EnableCipher(PKCS12_RC4_128, 1);
SEC_PKCS12EnableCipher(PKCS12_RC2_CBC_40, 1);
SEC_PKCS12EnableCipher(PKCS12_RC2_CBC_128, 1);
SEC_PKCS12EnableCipher(PKCS12_DES_56, 1);
SEC_PKCS12EnableCipher(PKCS12_DES_EDE3_168, 1);
SEC_PKCS12SetPreferredCipher(PKCS12_DES_EDE3_168, 1);
initialized = TRUE;
return TRUE;
}
void
crypto_deinit (void)
{
if (initialized) {
NSS_Shutdown ();
PR_Cleanup ();
}
}
gboolean
crypto_md5_hash (const char *salt,
const gsize salt_len,
const char *password,
gsize password_len,
char *buffer,
gsize buflen,
GError **error)
{
PK11Context *ctx;
int nkey = buflen;
unsigned int digest_len;
int count = 0;
char digest[MD5_HASH_LEN];
char *p = buffer;
if (salt)
g_return_val_if_fail (salt_len >= 8, FALSE);
g_return_val_if_fail (password != NULL, FALSE);
g_return_val_if_fail (password_len > 0, FALSE);
g_return_val_if_fail (buffer != NULL, FALSE);
g_return_val_if_fail (buflen > 0, FALSE);
ctx = PK11_CreateDigestContext (SEC_OID_MD5);
if (!ctx) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_MD5_INIT_FAILED,
_("Failed to initialize the MD5 context: %d."),
PORT_GetError ());
return FALSE;
}
while (nkey > 0) {
int i = 0;
PK11_DigestBegin (ctx);
if (count++)
PK11_DigestOp (ctx, (const unsigned char *) digest, digest_len);
PK11_DigestOp (ctx, (const unsigned char *) password, password_len);
if (salt)
PK11_DigestOp (ctx, (const unsigned char *) salt, 8); /* Only use 8 bytes of salt */
PK11_DigestFinal (ctx, (unsigned char *) digest, &digest_len, sizeof (digest));
while (nkey && (i < digest_len)) {
*(p++) = digest[i++];
nkey--;
}
}
memset (digest, 0, sizeof (digest));
PK11_DestroyContext (ctx, PR_TRUE);
return TRUE;
}
char *
crypto_decrypt (const char *cipher,
int key_type,
GByteArray *data,
const char *iv,
const gsize iv_len,
const char *key,
const gsize key_len,
gsize *out_len,
GError **error)
{
char *output = NULL;
int decrypted_len = 0;
CK_MECHANISM_TYPE cipher_mech;
PK11SlotInfo *slot = NULL;
SECItem key_item;
PK11SymKey *sym_key = NULL;
SECItem *sec_param = NULL;
PK11Context *ctx = NULL;
SECStatus s;
gboolean success = FALSE;
unsigned int pad_len = 0;
guint32 i, real_iv_len = 0;
if (!strcmp (cipher, CIPHER_DES_EDE3_CBC)) {
cipher_mech = CKM_DES3_CBC_PAD;
real_iv_len = 8;
} else if (!strcmp (cipher, CIPHER_DES_CBC)) {
cipher_mech = CKM_DES_CBC_PAD;
real_iv_len = 8;
} else {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_UNKNOWN_CIPHER,
_("Private key cipher '%s' was unknown."),
cipher);
return NULL;
}
if (iv_len < real_iv_len) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_RAW_IV_INVALID,
_("Invalid IV length (must be at least %d)."),
real_iv_len);
return NULL;
}
output = g_malloc0 (data->len);
if (!output) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_OUT_OF_MEMORY,
_("Not enough memory for decrypted key buffer."));
return NULL;
}
slot = PK11_GetBestSlot (cipher_mech, NULL);
if (!slot) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_INIT_FAILED,
_("Failed to initialize the decryption cipher slot."));
goto out;
}
key_item.data = (unsigned char *) key;
key_item.len = key_len;
sym_key = PK11_ImportSymKey (slot, cipher_mech, PK11_OriginUnwrap, CKA_DECRYPT, &key_item, NULL);
if (!sym_key) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_SET_KEY_FAILED,
_("Failed to set symmetric key for decryption."));
goto out;
}
key_item.data = (unsigned char *) iv;
key_item.len = real_iv_len;
sec_param = PK11_ParamFromIV (cipher_mech, &key_item);
if (!sec_param) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_SET_IV_FAILED,
_("Failed to set IV for decryption."));
goto out;
}
ctx = PK11_CreateContextBySymKey (cipher_mech, CKA_DECRYPT, sym_key, sec_param);
if (!ctx) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_INIT_FAILED,
_("Failed to initialize the decryption context."));
goto out;
}
s = PK11_CipherOp (ctx,
(unsigned char *) output,
&decrypted_len,
data->len,
data->data,
data->len);
if (s != SECSuccess) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Failed to decrypt the private key: %d."),
PORT_GetError ());
goto out;
}
if (decrypted_len > data->len) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Failed to decrypt the private key: decrypted data too large."));
goto out;
}
s = PK11_DigestFinal (ctx,
(unsigned char *) (output + decrypted_len),
&pad_len,
data->len - decrypted_len);
if (s != SECSuccess) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Failed to finalize decryption of the private key: %d."),
PORT_GetError ());
goto out;
}
pad_len = data->len - decrypted_len;
/* Check if the padding at the end of the decrypted data is valid */
if (pad_len == 0 || pad_len > real_iv_len) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Failed to decrypt the private key: unexpected padding length."));
goto out;
}
/* Validate tail padding; last byte is the padding size, and all pad bytes
* should contain the padding size.
*/
for (i = 1; i <= pad_len; ++i) {
if (output[data->len - i] != pad_len) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Failed to decrypt the private key."));
goto out;
}
}
*out_len = decrypted_len;
success = TRUE;
out:
if (ctx)
PK11_DestroyContext (ctx, PR_TRUE);
if (sym_key)
PK11_FreeSymKey (sym_key);
if (sec_param)
SECITEM_FreeItem (sec_param, PR_TRUE);
if (slot)
PK11_FreeSlot (slot);
if (!success) {
if (output) {
/* Don't expose key material */
memset (output, 0, data->len);
g_free (output);
output = NULL;
}
}
return output;
}
char *
crypto_encrypt (const char *cipher,
const GByteArray *data,
const char *iv,
gsize iv_len,
const char *key,
gsize key_len,
gsize *out_len,
GError **error)
{
SECStatus ret;
CK_MECHANISM_TYPE cipher_mech = CKM_DES3_CBC_PAD;
PK11SlotInfo *slot = NULL;
SECItem key_item = { .data = (unsigned char *) key, .len = key_len };
SECItem iv_item = { .data = (unsigned char *) iv, .len = iv_len };
PK11SymKey *sym_key = NULL;
SECItem *sec_param = NULL;
PK11Context *ctx = NULL;
unsigned char *output, *padded_buf;
gsize output_len;
int encrypted_len = 0, i;
gboolean success = FALSE;
gsize padded_buf_len, pad_len;
if (!strcmp (cipher, CIPHER_DES_EDE3_CBC))
cipher_mech = CKM_DES3_CBC_PAD;
else {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_UNKNOWN_CIPHER,
_("Private key cipher '%s' was unknown."),
cipher);
return NULL;
}
/* If data->len % ivlen == 0, then we add another complete block
* onto the end so that the decrypter knows there's padding.
*/
pad_len = iv_len - (data->len % iv_len);
output_len = padded_buf_len = data->len + pad_len;
padded_buf = g_malloc0 (padded_buf_len);
memcpy (padded_buf, data->data, data->len);
for (i = 0; i < pad_len; i++)
padded_buf[data->len + i] = (guint8) (pad_len & 0xFF);
output = g_malloc0 (output_len);
if (!output) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_OUT_OF_MEMORY,
_("Could not allocate memory for encrypting."));
return NULL;
}
slot = PK11_GetBestSlot (cipher_mech, NULL);
if (!slot) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_INIT_FAILED,
_("Failed to initialize the encryption cipher slot."));
goto out;
}
sym_key = PK11_ImportSymKey (slot, cipher_mech, PK11_OriginUnwrap, CKA_ENCRYPT, &key_item, NULL);
if (!sym_key) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_SET_KEY_FAILED,
_("Failed to set symmetric key for encryption."));
goto out;
}
sec_param = PK11_ParamFromIV (cipher_mech, &iv_item);
if (!sec_param) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_SET_IV_FAILED,
_("Failed to set IV for encryption."));
goto out;
}
ctx = PK11_CreateContextBySymKey (cipher_mech, CKA_ENCRYPT, sym_key, sec_param);
if (!ctx) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_INIT_FAILED,
_("Failed to initialize the encryption context."));
goto out;
}
ret = PK11_CipherOp (ctx, output, &encrypted_len, output_len, padded_buf, padded_buf_len);
if (ret != SECSuccess) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_ENCRYPT_FAILED,
_("Failed to encrypt: %d."),
PORT_GetError ());
goto out;
}
if (encrypted_len != output_len) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_ENCRYPT_FAILED,
_("Unexpected amount of data after encrypting."));
goto out;
}
*out_len = encrypted_len;
success = TRUE;
out:
if (ctx)
PK11_DestroyContext (ctx, PR_TRUE);
if (sym_key)
PK11_FreeSymKey (sym_key);
if (sec_param)
SECITEM_FreeItem (sec_param, PR_TRUE);
if (slot)
PK11_FreeSlot (slot);
if (padded_buf) {
memset (padded_buf, 0, padded_buf_len);
g_free (padded_buf);
padded_buf = NULL;
}
if (!success) {
memset (output, 0, output_len);
g_free (output);
output = NULL;
}
return (char *) output;
}
NMCryptoFileFormat
crypto_verify_cert (const unsigned char *data,
gsize len,
GError **error)
{
CERTCertificate *cert;
/* Try DER/PEM first */
cert = CERT_DecodeCertFromPackage ((char *) data, len);
if (!cert) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CERT_FORMAT_INVALID,
_("Couldn't decode certificate: %d"),
PORT_GetError());
return NM_CRYPTO_FILE_FORMAT_UNKNOWN;
}
CERT_DestroyCertificate (cert);
return NM_CRYPTO_FILE_FORMAT_X509;
}
gboolean
crypto_verify_pkcs12 (const GByteArray *data,
const char *password,
GError **error)
{
SEC_PKCS12DecoderContext *p12ctx = NULL;
SECItem pw = { 0 };
PK11SlotInfo *slot = NULL;
SECStatus s;
char *ucs2_password;
glong ucs2_chars = 0;
#ifndef WORDS_BIGENDIAN
guint16 *p;
#endif /* WORDS_BIGENDIAN */
if (error)
g_return_val_if_fail (*error == NULL, FALSE);
/* PKCS#12 passwords are apparently UCS2 BIG ENDIAN, and NSS doesn't do
* any conversions for us.
*/
if (password && strlen (password)) {
ucs2_password = (char *) g_utf8_to_utf16 (password, strlen (password), NULL, &ucs2_chars, NULL);
if (!ucs2_password || !ucs2_chars) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_INVALID_PASSWORD,
_("Couldn't convert password to UCS2: %d"),
PORT_GetError());
return FALSE;
}
ucs2_chars *= 2; /* convert # UCS2 characters -> bytes */
pw.data = PORT_ZAlloc(ucs2_chars + 2);
memcpy (pw.data, ucs2_password, ucs2_chars);
pw.len = ucs2_chars + 2; /* include terminating NULL */
memset (ucs2_password, 0, ucs2_chars);
g_free (ucs2_password);
#ifndef WORDS_BIGENDIAN
for (p = (guint16 *) pw.data; p < (guint16 *) (pw.data + pw.len); p++)
*p = GUINT16_SWAP_LE_BE (*p);
#endif /* WORDS_BIGENDIAN */
} else {
/* NULL password */
pw.data = NULL;
pw.len = 0;
}
slot = PK11_GetInternalKeySlot();
p12ctx = SEC_PKCS12DecoderStart (&pw, slot, NULL, NULL, NULL, NULL, NULL, NULL);
if (!p12ctx) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_DECODE_FAILED,
_("Couldn't initialize PKCS#12 decoder: %d"),
PORT_GetError());
goto error;
}
s = SEC_PKCS12DecoderUpdate (p12ctx, data->data, data->len);
if (s != SECSuccess) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_FILE_FORMAT_INVALID,
_("Couldn't decode PKCS#12 file: %d"),
PORT_GetError());
goto error;
}
s = SEC_PKCS12DecoderVerify (p12ctx);
if (s != SECSuccess) {
g_set_error (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_CIPHER_DECRYPT_FAILED,
_("Couldn't verify PKCS#12 file: %d"),
PORT_GetError());
goto error;
}
SEC_PKCS12DecoderFinish (p12ctx);
SECITEM_ZfreeItem (&pw, PR_FALSE);
return TRUE;
error:
if (p12ctx)
SEC_PKCS12DecoderFinish (p12ctx);
if (slot)
PK11_FreeSlot(slot);
SECITEM_ZfreeItem (&pw, PR_FALSE);
return FALSE;
}
gboolean
crypto_randomize (void *buffer, gsize buffer_len, GError **error)
{
SECStatus s;
s = PK11_GenerateRandom (buffer, buffer_len);
if (s != SECSuccess) {
g_set_error_literal (error, NM_CRYPTO_ERROR,
NM_CRYPTO_ERR_RANDOMIZE_FAILED,
_("Could not generate random data."));
return FALSE;
}
return TRUE;
}
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