/*
* Verify a plaintext password against a SCRAM verifier. This is used when
* performing plaintext password authentication for a user that has a SCRAM
* verifier stored in pg_authid.
*/
bool
scram_verify_plain_password(const char *username, const char *password,
const char *verifier)
{
char *encoded_salt;
char *salt;
int saltlen;
int iterations;
uint8 salted_password[SCRAM_KEY_LEN];
uint8 stored_key[SCRAM_KEY_LEN];
uint8 server_key[SCRAM_KEY_LEN];
uint8 computed_key[SCRAM_KEY_LEN];
char *prep_password = NULL;
pg_saslprep_rc rc;
if (!parse_scram_verifier(verifier, &iterations, &encoded_salt,
stored_key, server_key))
{
/*
* The password looked like a SCRAM verifier, but could not be parsed.
*/
ereport(LOG,
(errmsg("invalid SCRAM verifier for user \"%s\"", username)));
return false;
}
salt = palloc(pg_b64_dec_len(strlen(encoded_salt)));
saltlen = pg_b64_decode(encoded_salt, strlen(encoded_salt), salt);
if (saltlen == -1)
{
ereport(LOG,
(errmsg("invalid SCRAM verifier for user \"%s\"", username)));
return false;
}
/* Normalize the password */
rc = pg_saslprep(password, &prep_password);
if (rc == SASLPREP_SUCCESS)
password = prep_password;
/* Compute Server Key based on the user-supplied plaintext password */
scram_SaltedPassword(password, salt, saltlen, iterations, salted_password);
scram_ServerKey(salted_password, computed_key);
if (prep_password)
pfree(prep_password);
/*
* Compare the verifier's Server Key with the one computed from the
* user-supplied password.
*/
return memcmp(computed_key, server_key, SCRAM_KEY_LEN) == 0;
}
/*
* Read and parse the final message received from client.
*/
static void
read_client_final_message(scram_state *state, char *input)
{
char attr;
char *channel_binding;
char *value;
char *begin,
*proof;
char *p;
char *client_proof;
begin = p = pstrdup(input);
/*------
* The syntax for the server-first-message is: (RFC 5802)
*
* gs2-header = gs2-cbind-flag "," [ authzid ] ","
* ;; GS2 header for SCRAM
* ;; (the actual GS2 header includes an optional
* ;; flag to indicate that the GSS mechanism is not
* ;; "standard", but since SCRAM is "standard", we
* ;; don't include that flag).
*
* cbind-input = gs2-header [ cbind-data ]
* ;; cbind-data MUST be present for
* ;; gs2-cbind-flag of "p" and MUST be absent
* ;; for "y" or "n".
*
* channel-binding = "c=" base64
* ;; base64 encoding of cbind-input.
*
* proof = "p=" base64
*
* client-final-message-without-proof =
* channel-binding "," nonce [","
* extensions]
*
* client-final-message =
* client-final-message-without-proof "," proof
*------
*/
/*
* Read channel-binding. We don't support channel binding, so it's
* expected to always be "biws", which is "n,,", base64-encoded, or
* "eSws", which is "y,,". We also have to check whether the flag is
* the same one that the client originally sent.
*/
channel_binding = read_attr_value(&p, 'c');
if (!(strcmp(channel_binding, "biws") == 0 && state->cbind_flag == 'n') &&
!(strcmp(channel_binding, "eSws") == 0 && state->cbind_flag == 'y'))
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
(errmsg("unexpected SCRAM channel-binding attribute in client-final-message"))));
state->client_final_nonce = read_attr_value(&p, 'r');
/* ignore optional extensions */
do
{
proof = p - 1;
value = read_any_attr(&p, &attr);
} while (attr != 'p');
client_proof = palloc(pg_b64_dec_len(strlen(value)));
if (pg_b64_decode(value, strlen(value), client_proof) != SCRAM_KEY_LEN)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("malformed SCRAM message"),
errdetail("Malformed proof in client-final-message.")));
memcpy(state->ClientProof, client_proof, SCRAM_KEY_LEN);
pfree(client_proof);
if (*p != '\0')
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("malformed SCRAM message"),
errdetail("Garbage found at the end of client-final-message.")));
state->client_final_message_without_proof = palloc(proof - begin + 1);
memcpy(state->client_final_message_without_proof, input, proof - begin);
state->client_final_message_without_proof[proof - begin] = '\0';
}
/*
* Parse and validate format of given SCRAM verifier.
*
* Returns true if the SCRAM verifier has been parsed, and false otherwise.
*/
static bool
parse_scram_verifier(const char *verifier, int *iterations, char **salt,
uint8 *stored_key, uint8 *server_key)
{
char *v;
char *p;
char *scheme_str;
char *salt_str;
char *iterations_str;
char *storedkey_str;
char *serverkey_str;
int decoded_len;
char *decoded_salt_buf;
/*
* The verifier is of form:
*
* SCRAM-SHA-256$<iterations>:<salt>$<storedkey>:<serverkey>
*/
v = pstrdup(verifier);
if ((scheme_str = strtok(v, "$")) == NULL)
goto invalid_verifier;
if ((iterations_str = strtok(NULL, ":")) == NULL)
goto invalid_verifier;
if ((salt_str = strtok(NULL, "$")) == NULL)
goto invalid_verifier;
if ((storedkey_str = strtok(NULL, ":")) == NULL)
goto invalid_verifier;
if ((serverkey_str = strtok(NULL, "")) == NULL)
goto invalid_verifier;
/* Parse the fields */
if (strcmp(scheme_str, "SCRAM-SHA-256") != 0)
goto invalid_verifier;
errno = 0;
*iterations = strtol(iterations_str, &p, 10);
if (*p || errno != 0)
goto invalid_verifier;
/*
* Verify that the salt is in Base64-encoded format, by decoding it,
* although we return the encoded version to the caller.
*/
decoded_salt_buf = palloc(pg_b64_dec_len(strlen(salt_str)));
decoded_len = pg_b64_decode(salt_str, strlen(salt_str), decoded_salt_buf);
if (decoded_len < 0)
goto invalid_verifier;
*salt = pstrdup(salt_str);
/*
* Decode StoredKey and ServerKey.
*/
if (pg_b64_dec_len(strlen(storedkey_str) != SCRAM_KEY_LEN))
goto invalid_verifier;
decoded_len = pg_b64_decode(storedkey_str, strlen(storedkey_str),
(char *) stored_key);
if (decoded_len != SCRAM_KEY_LEN)
goto invalid_verifier;
if (pg_b64_dec_len(strlen(serverkey_str) != SCRAM_KEY_LEN))
goto invalid_verifier;
decoded_len = pg_b64_decode(serverkey_str, strlen(serverkey_str),
(char *) server_key);
if (decoded_len != SCRAM_KEY_LEN)
goto invalid_verifier;
return true;
invalid_verifier:
pfree(v);
*salt = NULL;
return false;
}
/*
* Read and parse the final message received from client.
*/
static void
read_client_final_message(scram_state *state, char *input)
{
char attr;
char *channel_binding;
char *value;
char *begin,
*proof;
char *p;
char *client_proof;
begin = p = pstrdup(input);
/*------
* The syntax for the server-first-message is: (RFC 5802)
*
* gs2-header = gs2-cbind-flag "," [ authzid ] ","
* ;; GS2 header for SCRAM
* ;; (the actual GS2 header includes an optional
* ;; flag to indicate that the GSS mechanism is not
* ;; "standard", but since SCRAM is "standard", we
* ;; don't include that flag).
*
* cbind-input = gs2-header [ cbind-data ]
* ;; cbind-data MUST be present for
* ;; gs2-cbind-flag of "p" and MUST be absent
* ;; for "y" or "n".
*
* channel-binding = "c=" base64
* ;; base64 encoding of cbind-input.
*
* proof = "p=" base64
*
* client-final-message-without-proof =
* channel-binding "," nonce [","
* extensions]
*
* client-final-message =
* client-final-message-without-proof "," proof
*------
*/
/*
* Read channel binding. This repeats the channel-binding flags and is
* then followed by the actual binding data depending on the type.
*/
channel_binding = read_attr_value(&p, 'c');
if (state->channel_binding_in_use)
{
#ifdef HAVE_BE_TLS_GET_CERTIFICATE_HASH
const char *cbind_data = NULL;
size_t cbind_data_len = 0;
size_t cbind_header_len;
char *cbind_input;
size_t cbind_input_len;
char *b64_message;
int b64_message_len;
Assert(state->cbind_flag == 'p');
/* Fetch hash data of server's SSL certificate */
cbind_data = be_tls_get_certificate_hash(state->port,
&cbind_data_len);
/* should not happen */
if (cbind_data == NULL || cbind_data_len == 0)
elog(ERROR, "could not get server certificate hash");
cbind_header_len = strlen("p=tls-server-end-point,,"); /* p=type,, */
cbind_input_len = cbind_header_len + cbind_data_len;
cbind_input = palloc(cbind_input_len);
snprintf(cbind_input, cbind_input_len, "p=tls-server-end-point,,");
memcpy(cbind_input + cbind_header_len, cbind_data, cbind_data_len);
b64_message = palloc(pg_b64_enc_len(cbind_input_len) + 1);
b64_message_len = pg_b64_encode(cbind_input, cbind_input_len,
b64_message);
b64_message[b64_message_len] = '\0';
/*
* Compare the value sent by the client with the value expected by the
* server.
*/
if (strcmp(channel_binding, b64_message) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
(errmsg("SCRAM channel binding check failed"))));
#else
/* shouldn't happen, because we checked this earlier already */
elog(ERROR, "channel binding not supported by this build");
#endif
}
else
{
/*
* If we are not using channel binding, the binding data is expected
* to always be "biws", which is "n,," base64-encoded, or "eSws",
* which is "y,,". We also have to check whether the flag is the same
* one that the client originally sent.
*/
if (!(strcmp(channel_binding, "biws") == 0 && state->cbind_flag == 'n') &&
!(strcmp(channel_binding, "eSws") == 0 && state->cbind_flag == 'y'))
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
(errmsg("unexpected SCRAM channel-binding attribute in client-final-message"))));
}
state->client_final_nonce = read_attr_value(&p, 'r');
/* ignore optional extensions */
do
{
proof = p - 1;
value = read_any_attr(&p, &attr);
} while (attr != 'p');
client_proof = palloc(pg_b64_dec_len(strlen(value)));
if (pg_b64_decode(value, strlen(value), client_proof) != SCRAM_KEY_LEN)
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("malformed SCRAM message"),
errdetail("Malformed proof in client-final-message.")));
memcpy(state->ClientProof, client_proof, SCRAM_KEY_LEN);
pfree(client_proof);
if (*p != '\0')
ereport(ERROR,
(errcode(ERRCODE_PROTOCOL_VIOLATION),
errmsg("malformed SCRAM message"),
errdetail("Garbage found at the end of client-final-message.")));
state->client_final_message_without_proof = palloc(proof - begin + 1);
memcpy(state->client_final_message_without_proof, input, proof - begin);
state->client_final_message_without_proof[proof - begin] = '\0';
}
int
main(int argc, char *argv[])
{
#define PRINT_USAGE(exit_code) print_usage(argv[0], exit_code)
char conf_file[POOLMAXPATHLEN + 1];
char enc_key[MAX_POOL_KEY_LEN + 1];
char pg_pass[MAX_PGPASS_LEN + 1];
char username[MAX_USER_NAME_LEN + 1];
char key_file_path[POOLMAXPATHLEN + sizeof(POOLKEYFILE) + 1];
int opt;
int optindex;
bool updatepasswd = false;
bool prompt = false;
bool prompt_for_key = false;
char *pool_key = NULL;
static struct option long_options[] = {
{"help", no_argument, NULL, 'h'},
{"prompt", no_argument, NULL, 'p'},
{"prompt-for-key", no_argument, NULL, 'P'},
{"update-pass", no_argument, NULL, 'm'},
{"username", required_argument, NULL, 'u'},
{"enc-key", required_argument, NULL, 'K'},
{"key-file", required_argument, NULL, 'k'},
{"config-file", required_argument, NULL, 'f'},
{NULL, 0, NULL, 0}
};
snprintf(conf_file, sizeof(conf_file), "%s/%s", DEFAULT_CONFIGDIR, POOL_CONF_FILE_NAME);
/*
* initialize username buffer with zeros so that we can use strlen on it
* later to check if a username was given on the command line
*/
memset(username, 0, sizeof(username));
memset(enc_key, 0, sizeof(enc_key));
memset(key_file_path, 0, sizeof(key_file_path));
while ((opt = getopt_long(argc, argv, "hPpmf:u:k:K:", long_options, &optindex)) != -1)
{
switch (opt)
{
case 'p': /* prompt for postgres password */
prompt = true;
break;
case 'P': /* prompt for encryption key */
prompt_for_key = true;
break;
case 'm': /* update password file */
updatepasswd = true;
break;
case 'f': /* specify configuration file */
if (!optarg)
{
PRINT_USAGE(EXIT_SUCCESS);
}
strlcpy(conf_file, optarg, sizeof(conf_file));
break;
case 'k': /* specify key file for encrypting
* pool_password entries */
if (!optarg)
{
PRINT_USAGE(EXIT_SUCCESS);
}
strlcpy(key_file_path, optarg, sizeof(key_file_path));
break;
case 'K': /* specify configuration file */
if (!optarg)
{
PRINT_USAGE(EXIT_SUCCESS);
}
strlcpy(enc_key, optarg, sizeof(enc_key));
break;
case 'u':
if (!optarg)
{
PRINT_USAGE(EXIT_SUCCESS);
}
/* check the input limit early */
if (strlen(optarg) > sizeof(username))
{
fprintf(stderr, "Error: input exceeds maximum username length!\n\n");
exit(EXIT_FAILURE);
}
strlcpy(username, optarg, sizeof(username));
break;
default:
PRINT_USAGE(EXIT_SUCCESS);
break;
}
}
/* Prompt for password. */
if (prompt || optind >= argc)
{
char buf[MAX_PGPASS_LEN];
int len;
set_tio_attr(1);
printf("db password: "******"Couldn't read input from stdin. (fgets(): %s)",
strerror(eno));
exit(EXIT_FAILURE);
}
printf("\n");
set_tio_attr(0);
/* Remove LF at the end of line, if there is any. */
len = strlen(buf);
if (len > 0 && buf[len - 1] == '\n')
{
buf[len - 1] = '\0';
len--;
}
stpncpy(pg_pass, buf, sizeof(pg_pass));
}
/* Read password from argv. */
else
{
int len;
len = strlen(argv[optind]);
if (len > MAX_PGPASS_LEN)
{
fprintf(stderr, "Error: Input exceeds maximum password length given:%d max allowed:%d!\n\n", len, MAX_PGPASS_LEN);
PRINT_USAGE(EXIT_FAILURE);
}
stpncpy(pg_pass, argv[optind], sizeof(pg_pass));
}
/* prompt for key, overrides all key related arguments */
if (prompt_for_key)
{
char buf[MAX_POOL_KEY_LEN];
int len;
/* we need to read the encryption key from stdin */
set_tio_attr(1);
printf("encryption key: ");
if (!fgets(buf, sizeof(buf), stdin))
{
int eno = errno;
fprintf(stderr, "Couldn't read input from stdin. (fgets(): %s)",
strerror(eno));
exit(EXIT_FAILURE);
}
printf("\n");
set_tio_attr(0);
/* Remove LF at the end of line, if there is any. */
len = strlen(buf);
if (len > 0 && buf[len - 1] == '\n')
{
buf[len - 1] = '\0';
len--;
}
if (len == 0)
{
fprintf(stderr, "encryption key not provided\n");
exit(EXIT_FAILURE);
}
stpncpy(enc_key, buf, sizeof(enc_key));
}
else
{
/* check if we already have not got the key from command line argument */
if (strlen(enc_key) == 0)
{
/* read from file */
if (strlen(key_file_path) == 0)
{
get_pool_key_filename(key_file_path);
}
fprintf(stdout, "trying to read key from file %s\n", key_file_path);
pool_key = read_pool_key(key_file_path);
}
else
{
pool_key = enc_key;
}
}
if (pool_key == NULL)
{
fprintf(stderr, "encryption key not provided\n");
exit(EXIT_FAILURE);
}
if (updatepasswd)
{
update_pool_passwd(conf_file, username, pg_pass, pool_key);
}
else
{
unsigned char ciphertext[MAX_ENCODED_PASSWD_LEN];
unsigned char b64_enc[MAX_ENCODED_PASSWD_LEN];
int len;
int cypher_len;
cypher_len = aes_encrypt_with_password((unsigned char *) pg_pass,
strlen(pg_pass), pool_key, ciphertext);
/* generate the hash for the given username */
len = pg_b64_encode((const char *) ciphertext, cypher_len, (char *) b64_enc);
b64_enc[len] = 0;
fprintf(stdout, "\n%s\n", b64_enc);
fprintf(stdout, "pool_passwd string: AES%s\n", b64_enc);
#ifdef DEBUG_ENCODING
unsigned char b64_dec[MAX_ENCODED_PASSWD_LEN];
unsigned char plaintext[MAX_PGPASS_LEN];
len = pg_b64_decode(b64_enc, len, b64_dec);
len = aes_decrypt_with_password(b64_dec, len,
pool_key, plaintext);
plaintext[len] = 0;
#endif
}
if (pool_key != enc_key)
free(pool_key);
return EXIT_SUCCESS;
}
