Fix error handling of pg_b64_decode()

Fix for commit 761c79508e7.  The previous error handling logic was not
quite correct.

Discussion: https://www.postgresql.org/message-id/flat/CAEudQAq-3yHsSdWoOOaw%2BgAQYgPMpMGuB5pt2yCXgv-YuxG2Hg%40mail.gmail.com

diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index c7943d549e88462a2d60d05d8c6dcf3061103895..7878e2e33afe0a9123ef69ca25a472446fe65848 100644 (file)
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -1805,18 +1805,24 @@ pqConnectOptions2(PGconn *conn)
        int         len;
 
        len = pg_b64_dec_len(strlen(conn->scram_client_key));
-       /* Consider the zero-terminator */
-       if (len != SCRAM_MAX_KEY_LEN + 1)
+       conn->scram_client_key_binary = malloc(len);
+       if (!conn->scram_client_key_binary)
+           goto oom_error;
+       len = pg_b64_decode(conn->scram_client_key, strlen(conn->scram_client_key),
+                           conn->scram_client_key_binary, len);
+       if (len < 0)
+       {
+           libpq_append_conn_error(conn, "invalid SCRAM client key");
+           free(conn->scram_client_key_binary);
+           return false;
+       }
+       if (len != SCRAM_MAX_KEY_LEN)
        {
            libpq_append_conn_error(conn, "invalid SCRAM client key length: %d", len);
+           free(conn->scram_client_key_binary);
            return false;
        }
        conn->scram_client_key_len = len;
-       conn->scram_client_key_binary = malloc(len);
-       if (!conn->scram_client_key_binary)
-           goto oom_error;
-       pg_b64_decode(conn->scram_client_key, strlen(conn->scram_client_key),
-                     conn->scram_client_key_binary, len);
    }
 
    if (conn->scram_server_key)
@@ -1824,18 +1830,24 @@ pqConnectOptions2(PGconn *conn)
        int         len;
 
        len = pg_b64_dec_len(strlen(conn->scram_server_key));
-       /* Consider the zero-terminator */
-       if (len != SCRAM_MAX_KEY_LEN + 1)
+       conn->scram_server_key_binary = malloc(len);
+       if (!conn->scram_server_key_binary)
+           goto oom_error;
+       len = pg_b64_decode(conn->scram_server_key, strlen(conn->scram_server_key),
+                           conn->scram_server_key_binary, len);
+       if (len < 0)
+       {
+           libpq_append_conn_error(conn, "invalid SCRAM server key");
+           free(conn->scram_server_key_binary);
+           return false;
+       }
+       if (len != SCRAM_MAX_KEY_LEN)
        {
            libpq_append_conn_error(conn, "invalid SCRAM server key length: %d", len);
+           free(conn->scram_server_key_binary);
            return false;
        }
        conn->scram_server_key_len = len;
-       conn->scram_server_key_binary = malloc(len);
-       if (!conn->scram_server_key_binary)
-           goto oom_error;
-       pg_b64_decode(conn->scram_server_key, strlen(conn->scram_server_key),
-                     conn->scram_server_key_binary, len);
    }
 
    /*