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authorJakub Hrozek <jhrozek@redhat.com>2011-01-17 13:28:12 +0100
committerStephen Gallagher <sgallagh@redhat.com>2011-01-20 12:20:40 -0500
commitfd72f761edb0b11265ce3293b56a4a4fa0d1a317 (patch)
treef82537940ba4d8da6b56d55d79aa25526995a512
parent3c13b616108d4c0a413380ba72189947898eee57 (diff)
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NSS obfuscation code cleanup
https://fedorahosted.org/sssd/ticket/752
-rw-r--r--src/util/crypto/nss/nss_obfuscate.c135
1 files changed, 97 insertions, 38 deletions
diff --git a/src/util/crypto/nss/nss_obfuscate.c b/src/util/crypto/nss/nss_obfuscate.c
index 1c6eb1d7..a14284e8 100644
--- a/src/util/crypto/nss/nss_obfuscate.c
+++ b/src/util/crypto/nss/nss_obfuscate.c
@@ -21,6 +21,15 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+/*
+ * READ ME:
+ *
+ * Please note that password obfuscation does not improve security in any
+ * way. It is just a mechanism to make the password human-unreadable. If you
+ * need to secure passwords in your application, you should probably take a
+ * look at storing passwords in NSS-backed database.
+ */
+
#include "config.h"
#include <prerror.h>
@@ -74,31 +83,63 @@ static struct crypto_mech_data *get_crypto_mech_data(enum obfmethod meth)
return &cmdata[meth];
}
-static int generate_random_key(TALLOC_CTX *mem_ctx, size_t keylen,
- unsigned char **_key)
+static int generate_random_key(TALLOC_CTX *mem_ctx,
+ PK11SlotInfo *slot,
+ struct crypto_mech_data *mech_props,
+ SECItem **_key)
{
- unsigned char *randkey;
SECStatus sret;
+ SECItem *randkeydata;
+ SECItem *key;
+ PK11SymKey *randkey;
int ret;
- randkey = talloc_size(mem_ctx, keylen);
+ randkey = PK11_KeyGen(slot, mech_props->cipher,
+ NULL, mech_props->keylen, NULL);
if (randkey == NULL) {
- ret = ENOMEM;
+ DEBUG(1, ("Failure to generate key (err %d)\n",
+ PR_GetError()));
+ ret = EIO;
goto done;
}
- sret = PK11_GenerateRandom(randkey, keylen);
+ sret = PK11_ExtractKeyValue(randkey);
if (sret != SECSuccess) {
- DEBUG(1, ("Unable to generate random data (err %d)\n",
+ DEBUG(1, ("Failure to extract key value (err %d)\n",
PR_GetError()));
ret = EIO;
goto done;
}
- *_key = randkey;
+ randkeydata = PK11_GetKeyData(randkey);
+ if (randkey == NULL) {
+ DEBUG(1, ("Failure to get key data (err %d)\n",
+ PR_GetError()));
+ ret = EIO;
+ goto done;
+ }
+
+ /* randkeydata is valid until randkey is. Copy with talloc to
+ * get a nice memory hierarchy symmetrical in encrypt
+ * and decrypt case */
+ key = talloc_zero(mem_ctx, SECItem);
+ if (!key) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ key->data = talloc_memdup(key, randkeydata->data, randkeydata->len);
+ if (!key->data) {
+ ret = ENOMEM;
+ goto done;
+ }
+ key->len = randkeydata->len;
+
+ *_key = key;
ret = EOK;
done:
- if (ret != EOK) talloc_zfree(randkey);
+ if (ret != EOK) talloc_zfree(key);
+ PK11_FreeSymKey(randkey);
return ret;
}
@@ -112,15 +153,11 @@ static int sss_nss_crypto_ctx_destructor(struct sss_nss_crypto_ctx *cctx)
return EOK;
}
-static int nss_encrypt_decrypt_init(TALLOC_CTX *mem_ctx,
- struct crypto_mech_data *mech_props,
- bool encrypt,
- unsigned char *ivbuf,
- unsigned char *keybuf,
- struct sss_nss_crypto_ctx **_cctx)
+static int nss_ctx_init(TALLOC_CTX *mem_ctx,
+ struct crypto_mech_data *mech_props,
+ struct sss_nss_crypto_ctx **_cctx)
{
struct sss_nss_crypto_ctx *cctx;
- CK_ATTRIBUTE_TYPE op;
int ret;
cctx = talloc_zero(mem_ctx, struct sss_nss_crypto_ctx);
@@ -129,18 +166,6 @@ static int nss_encrypt_decrypt_init(TALLOC_CTX *mem_ctx,
}
talloc_set_destructor(cctx, sss_nss_crypto_ctx_destructor);
- cctx->iv = talloc_zero(cctx, SECItem);
- cctx->key = talloc_zero(cctx, SECItem);
- if (!cctx->iv || !cctx->key) {
- ret = ENOMEM;
- goto done;
- }
-
- MAKE_SECITEM(ivbuf, mech_props->bsize, cctx->iv);
- MAKE_SECITEM(keybuf, mech_props->keylen, cctx->key);
-
- op = encrypt ? CKA_ENCRYPT : CKA_DECRYPT;
-
cctx->slot = PK11_GetBestSlot(mech_props->cipher, NULL);
if (cctx->slot == NULL) {
DEBUG(1, ("Unable to find security device (err %d)\n",
@@ -149,6 +174,23 @@ static int nss_encrypt_decrypt_init(TALLOC_CTX *mem_ctx,
goto done;
}
+ ret = EOK;
+ *_cctx = cctx;
+done:
+ if (ret) talloc_zfree(cctx);
+ return ret;
+}
+
+static int nss_encrypt_decrypt_init(TALLOC_CTX *mem_ctx,
+ struct crypto_mech_data *mech_props,
+ bool encrypt,
+ struct sss_nss_crypto_ctx *cctx)
+{
+ CK_ATTRIBUTE_TYPE op;
+ int ret;
+
+ op = encrypt ? CKA_ENCRYPT : CKA_DECRYPT;
+
/* turn the raw key into a key object */
cctx->keyobj = PK11_ImportSymKey(cctx->slot, mech_props->cipher,
PK11_OriginUnwrap, op, cctx->key, NULL);
@@ -179,9 +221,7 @@ static int nss_encrypt_decrypt_init(TALLOC_CTX *mem_ctx,
}
ret = EOK;
- *_cctx = cctx;
done:
- if (ret) talloc_zfree(cctx);
return ret;
}
@@ -226,8 +266,6 @@ int sss_password_encrypt(TALLOC_CTX *mem_ctx, const char *password, int plen,
struct crypto_mech_data *mech_props;
struct sss_nss_crypto_ctx *cctx;
- unsigned char *keybuf;
- unsigned char *ivbuf;
unsigned char *plaintext;
unsigned char *cryptotext;
@@ -258,22 +296,28 @@ int sss_password_encrypt(TALLOC_CTX *mem_ctx, const char *password, int plen,
goto done;
}
+ ret = nss_ctx_init(tmp_ctx, mech_props, &cctx);
+ if (ret) {
+ DEBUG(1, ("Cannot initialize NSS context\n"));
+ goto done;
+ }
+
/* generate random encryption and IV key */
- ret = generate_random_key(tmp_ctx, mech_props->keylen, &keybuf);
+ ret = generate_random_key(cctx, cctx->slot, mech_props, &cctx->key);
if (ret != EOK) {
DEBUG(1, ("Could not generate encryption key\n"));
goto done;
}
- ret = generate_random_key(tmp_ctx, mech_props->bsize, &ivbuf);
+ ret = generate_random_key(cctx, cctx->slot, mech_props, &cctx->iv);
if (ret != EOK) {
DEBUG(1, ("Could not generate initialization vector\n"));
goto done;
}
- ret = nss_encrypt_decrypt_init(tmp_ctx, mech_props, true,
- ivbuf, keybuf, &cctx);
+ ret = nss_encrypt_decrypt_init(tmp_ctx, mech_props, true, cctx);
if (ret) {
+ DEBUG(1, ("Cannot initialize NSS context properties\n"));
goto done;
}
@@ -440,8 +484,23 @@ int sss_password_decrypt(TALLOC_CTX *mem_ctx, char *b64encoded,
}
safealign_memcpy(cryptotext, obfbuf+p, ctsize, &p);
- ret = nss_encrypt_decrypt_init(tmp_ctx, mech_props, false,
- ivbuf, keybuf, &cctx);
+ ret = nss_ctx_init(tmp_ctx, mech_props, &cctx);
+ if (ret) {
+ DEBUG(1, ("Cannot initialize NSS context\n"));
+ goto done;
+ }
+
+ cctx->iv = talloc_zero(cctx, SECItem);
+ cctx->key = talloc_zero(cctx, SECItem);
+ if (!cctx->iv || !cctx->key) {
+ ret = ENOMEM;
+ goto done;
+ }
+
+ MAKE_SECITEM(ivbuf, mech_props->bsize, cctx->iv);
+ MAKE_SECITEM(keybuf, mech_props->keylen, cctx->key);
+
+ ret = nss_encrypt_decrypt_init(tmp_ctx, mech_props, false, cctx);
if (ret) {
goto done;
}