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author | Greg Hudson <ghudson@mit.edu> | 2023-02-13 15:08:56 -0500 |
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committer | Greg Hudson <ghudson@mit.edu> | 2023-03-01 19:14:21 -0500 |
commit | a3198b70b017a5bc4eb8d44eddf349e51b014c9b (patch) | |
tree | 44d001a11e624e96d841acff8ff8178a6fca831a /src/lib/kdb/decrypt_key.c | |
parent | fddd419fc4112a118d8091e296cc2bfa8d8f777b (diff) | |
download | krb5-a3198b70b017a5bc4eb8d44eddf349e51b014c9b.zip krb5-a3198b70b017a5bc4eb8d44eddf349e51b014c9b.tar.gz krb5-a3198b70b017a5bc4eb8d44eddf349e51b014c9b.tar.bz2 |
Modernize default key data encryption functions
Diffstat (limited to 'src/lib/kdb/decrypt_key.c')
-rw-r--r-- | src/lib/kdb/decrypt_key.c | 132 |
1 files changed, 64 insertions, 68 deletions
diff --git a/src/lib/kdb/decrypt_key.c b/src/lib/kdb/decrypt_key.c index 541064d..82bbed6 100644 --- a/src/lib/kdb/decrypt_key.c +++ b/src/lib/kdb/decrypt_key.c @@ -1,7 +1,7 @@ /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ /* lib/kdb/decrypt_key.c */ /* - * Copyright 1990,1991 by the Massachusetts Institute of Technology. + * Copyright 1990,1991,2023 by the Massachusetts Institute of Technology. * All Rights Reserved. * * Export of this software from the United States of America may @@ -52,88 +52,84 @@ #include "k5-int.h" #include "kdb.h" -/* - * Decrypt a key from storage in the database. "eblock" is used - * to decrypt the key in "in" into "out"; the storage pointed to by "out" - * is allocated before use. - */ - +/* Decrypt key_data, putting the result into dbkey_out and (if not null) + * keysalt_out. */ krb5_error_code -krb5_dbe_def_decrypt_key_data( krb5_context context, - const krb5_keyblock * mkey, - const krb5_key_data * key_data, - krb5_keyblock * dbkey, - krb5_keysalt * keysalt) +krb5_dbe_def_decrypt_key_data(krb5_context context, const krb5_keyblock *mkey, + const krb5_key_data *kd, + krb5_keyblock *dbkey_out, + krb5_keysalt *keysalt_out) { - krb5_error_code retval = 0; - krb5_int16 tmplen; - krb5_octet * ptr; - krb5_enc_data cipher; - krb5_data plain; + krb5_error_code ret; + int16_t keylen; + krb5_enc_data cipher; + krb5_data plain = empty_data(); + krb5_keyblock kb = { 0 }; + krb5_keysalt salt = { 0 }; - if (!mkey) - return KRB5_KDB_BADSTORED_MKEY; - ptr = key_data->key_data_contents[0]; + memset(dbkey_out, 0, sizeof(*dbkey_out)); + if (keysalt_out != NULL) + memset(keysalt_out, 0, sizeof(*keysalt_out)); - if (ptr) { - krb5_kdb_decode_int16(ptr, tmplen); - ptr += 2; + if (mkey == NULL) + return KRB5_KDB_BADSTORED_MKEY; - if (tmplen < 0) + if (kd->key_data_contents[0] != NULL && kd->key_data_length[0] >= 2) { + keylen = load_16_le(kd->key_data_contents[0]); + if (keylen < 0) return EINVAL; cipher.enctype = ENCTYPE_UNKNOWN; - cipher.ciphertext.length = key_data->key_data_length[0]-2; - cipher.ciphertext.data = (char *) ptr; - plain.length = key_data->key_data_length[0]-2; - if ((plain.data = malloc(plain.length)) == NULL) - return(ENOMEM); - - if ((retval = krb5_c_decrypt(context, mkey, 0 /* XXX */, 0, - &cipher, &plain))) { - free(plain.data); - return retval; - } + cipher.ciphertext = make_data(kd->key_data_contents[0] + 2, + kd->key_data_length[0] - 2); + ret = alloc_data(&plain, kd->key_data_length[0] - 2); + if (ret) + goto cleanup; - /* tmplen is the true length of the key. plain.data is the - plaintext data length, but it may be padded, since the - old-style etypes didn't store the real length. I can check - to make sure that there are enough bytes, but I can't do - any better than that. */ + ret = krb5_c_decrypt(context, mkey, 0, 0, &cipher, &plain); + if (ret) + goto cleanup; - if ((unsigned int) tmplen > plain.length) { - free(plain.data); - return(KRB5_CRYPTO_INTERNAL); + /* Make sure the plaintext has at least as many bytes as the true ke + * length (it may have more due to padding). */ + if ((unsigned int)keylen > plain.length) { + ret = KRB5_CRYPTO_INTERNAL; + if (ret) + goto cleanup; } - dbkey->magic = KV5M_KEYBLOCK; - dbkey->enctype = key_data->key_data_type[0]; - dbkey->length = tmplen; - dbkey->contents = (krb5_octet *) plain.data; + kb.magic = KV5M_KEYBLOCK; + kb.enctype = kd->key_data_type[0]; + kb.length = keylen; + kb.contents = (uint8_t *)plain.data; + plain = empty_data(); } - /* Decode salt data */ - if (keysalt) { - if (key_data->key_data_ver == 2) { - keysalt->type = key_data->key_data_type[1]; - if ((keysalt->data.length = key_data->key_data_length[1])) { - if (!(keysalt->data.data=(char *)malloc(keysalt->data.length))){ - if (key_data->key_data_contents[0]) { - free(dbkey->contents); - dbkey->contents = 0; - dbkey->length = 0; - } - return ENOMEM; - } - memcpy(keysalt->data.data, key_data->key_data_contents[1], - (size_t) keysalt->data.length); - } else - keysalt->data.data = (char *) NULL; + /* Decode salt data. */ + if (keysalt_out != NULL) { + if (kd->key_data_ver == 2) { + salt.type = kd->key_data_type[1]; + salt.data.length = kd->key_data_length[1]; + if (kd->key_data_length[1] > 0) { + ret = alloc_data(&salt.data, kd->key_data_length[1]); + if (ret) + goto cleanup; + memcpy(salt.data.data, kd->key_data_contents[1], + salt.data.length); + } } else { - keysalt->type = KRB5_KDB_SALTTYPE_NORMAL; - keysalt->data.data = (char *) NULL; - keysalt->data.length = 0; + salt.type = KRB5_KDB_SALTTYPE_NORMAL; } } - return retval; + *dbkey_out = kb; + if (keysalt_out != NULL) + *keysalt_out = salt; + memset(&kb, 0, sizeof(kb)); + memset(&salt, 0, sizeof(salt)); + +cleanup: + zapfree(plain.data, plain.length); + krb5_free_keyblock_contents(context, &kb); + free(salt.data.data); + return ret; } |