#include "libpq-fe.h"
+/*
+ * Possible states for the SASL exchange, see the comment on exchange for an
+ * explanation of these.
+ */
+typedef enum
+{
+ SASL_COMPLETE = 0,
+ SASL_FAILED,
+ SASL_CONTINUE,
+} SASLStatus;
+
/*
* Frontend SASL mechanism callbacks.
*
* Produces a client response to a server challenge. As a special case
* for client-first SASL mechanisms, exchange() is called with a NULL
* server response once at the start of the authentication exchange to
- * generate an initial response.
+ * generate an initial response. Returns a SASLStatus indicating the
+ * state and status of the exchange.
*
* Input parameters:
*
*
* output: A malloc'd buffer containing the client's response to
* the server (can be empty), or NULL if the exchange should
- * be aborted. (*success should be set to false in the
+ * be aborted. (The callback should return SASL_FAILED in the
* latter case.)
*
* outputlen: The length (0 or higher) of the client response buffer,
* ignored if output is NULL.
*
- * done: Set to true if the SASL exchange should not continue,
- * because the exchange is either complete or failed
+ * Return value:
*
- * success: Set to true if the SASL exchange completed successfully.
- * Ignored if *done is false.
+ * SASL_CONTINUE: The output buffer is filled with a client response.
+ * Additional server challenge is expected
+ * SASL_COMPLETE: The SASL exchange has completed successfully.
+ * SASL_FAILED: The exchange has failed and the connection should be
+ * dropped.
*--------
*/
- void (*exchange) (void *state, char *input, int inputlen,
- char **output, int *outputlen,
- bool *done, bool *success);
+ SASLStatus (*exchange) (void *state, char *input, int inputlen,
+ char **output, int *outputlen);
/*--------
* channel_bound()
/* The exported SCRAM callback mechanism. */
static void *scram_init(PGconn *conn, const char *password,
const char *sasl_mechanism);
-static void scram_exchange(void *opaq, char *input, int inputlen,
- char **output, int *outputlen,
- bool *done, bool *success);
+static SASLStatus scram_exchange(void *opaq, char *input, int inputlen,
+ char **output, int *outputlen);
static bool scram_channel_bound(void *opaq);
static void scram_free(void *opaq);
/*
* Exchange a SCRAM message with backend.
*/
-static void
+static SASLStatus
scram_exchange(void *opaq, char *input, int inputlen,
- char **output, int *outputlen,
- bool *done, bool *success)
+ char **output, int *outputlen)
{
fe_scram_state *state = (fe_scram_state *) opaq;
PGconn *conn = state->conn;
const char *errstr = NULL;
- *done = false;
- *success = false;
*output = NULL;
*outputlen = 0;
if (inputlen == 0)
{
libpq_append_conn_error(conn, "malformed SCRAM message (empty message)");
- goto error;
+ return SASL_FAILED;
}
if (inputlen != strlen(input))
{
libpq_append_conn_error(conn, "malformed SCRAM message (length mismatch)");
- goto error;
+ return SASL_FAILED;
}
}
/* Begin the SCRAM handshake, by sending client nonce */
*output = build_client_first_message(state);
if (*output == NULL)
- goto error;
+ return SASL_FAILED;
*outputlen = strlen(*output);
- *done = false;
state->state = FE_SCRAM_NONCE_SENT;
- break;
+ return SASL_CONTINUE;
case FE_SCRAM_NONCE_SENT:
/* Receive salt and server nonce, send response. */
if (!read_server_first_message(state, input))
- goto error;
+ return SASL_FAILED;
*output = build_client_final_message(state);
if (*output == NULL)
- goto error;
+ return SASL_FAILED;
*outputlen = strlen(*output);
- *done = false;
state->state = FE_SCRAM_PROOF_SENT;
- break;
+ return SASL_CONTINUE;
case FE_SCRAM_PROOF_SENT:
- /* Receive server signature */
- if (!read_server_final_message(state, input))
- goto error;
-
- /*
- * Verify server signature, to make sure we're talking to the
- * genuine server.
- */
- if (!verify_server_signature(state, success, &errstr))
- {
- libpq_append_conn_error(conn, "could not verify server signature: %s", errstr);
- goto error;
- }
-
- if (!*success)
{
- libpq_append_conn_error(conn, "incorrect server signature");
+ bool match;
+
+ /* Receive server signature */
+ if (!read_server_final_message(state, input))
+ return SASL_FAILED;
+
+ /*
+ * Verify server signature, to make sure we're talking to the
+ * genuine server.
+ */
+ if (!verify_server_signature(state, &match, &errstr))
+ {
+ libpq_append_conn_error(conn, "could not verify server signature: %s", errstr);
+ return SASL_FAILED;
+ }
+
+ if (!match)
+ {
+ libpq_append_conn_error(conn, "incorrect server signature");
+ }
+ state->state = FE_SCRAM_FINISHED;
+ state->conn->client_finished_auth = true;
+ return match ? SASL_COMPLETE : SASL_FAILED;
}
- *done = true;
- state->state = FE_SCRAM_FINISHED;
- state->conn->client_finished_auth = true;
- break;
default:
/* shouldn't happen */
libpq_append_conn_error(conn, "invalid SCRAM exchange state");
- goto error;
+ break;
}
- return;
-error:
- *done = true;
- *success = false;
+ return SASL_FAILED;
}
/*
{
char *initialresponse = NULL;
int initialresponselen;
- bool done;
- bool success;
const char *selected_mechanism;
PQExpBufferData mechanism_buf;
char *password;
+ SASLStatus status;
initPQExpBuffer(&mechanism_buf);
goto oom_error;
/* Get the mechanism-specific Initial Client Response, if any */
- conn->sasl->exchange(conn->sasl_state,
- NULL, -1,
- &initialresponse, &initialresponselen,
- &done, &success);
+ status = conn->sasl->exchange(conn->sasl_state,
+ NULL, -1,
+ &initialresponse, &initialresponselen);
- if (done && !success)
+ if (status == SASL_FAILED)
goto error;
/*
{
char *output;
int outputlen;
- bool done;
- bool success;
int res;
char *challenge;
+ SASLStatus status;
/* Read the SASL challenge from the AuthenticationSASLContinue message. */
challenge = malloc(payloadlen + 1);
/* For safety and convenience, ensure the buffer is NULL-terminated. */
challenge[payloadlen] = '\0';
- conn->sasl->exchange(conn->sasl_state,
- challenge, payloadlen,
- &output, &outputlen,
- &done, &success);
+ status = conn->sasl->exchange(conn->sasl_state,
+ challenge, payloadlen,
+ &output, &outputlen);
free(challenge); /* don't need the input anymore */
- if (final && !done)
+ if (final && status == SASL_CONTINUE)
{
if (outputlen != 0)
free(output);
* If the exchange is not completed yet, we need to make sure that the
* SASL mechanism has generated a message to send back.
*/
- if (output == NULL && !done)
+ if (output == NULL && status == SASL_CONTINUE)
{
libpq_append_conn_error(conn, "no client response found after SASL exchange success");
return STATUS_ERROR;
return STATUS_ERROR;
}
- if (done && !success)
+ if (status == SASL_FAILED)
return STATUS_ERROR;
return STATUS_OK;
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