Give nicer error message when connecting to a v10 server requiring SCRAM.

This is just to give the user a hint that they need to upgrade, if they try
to connect to a v10 server that uses SCRAM authentication, with an older
client.

Commit to all stable branches, but not master.

Discussion: https://www.postgresql.org/message-id/bbf45d92-3896-eeb7-7399-2111d517261b@pivotal.io

diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h
index 639bf72e4edf129e98d934c9040df1401ca73149..a24c4a020a0f5cddce3f906f619637a5b56e5f1c 100644 (file)
--- a/src/include/libpq/pqcomm.h
+++ b/src/include/libpq/pqcomm.h
@@ -172,6 +172,8 @@ extern bool Db_user_namespace;
 #define AUTH_REQ_GSS       7   /* GSSAPI without wrap() */
 #define AUTH_REQ_GSS_CONT  8   /* Continue GSS exchanges */
 #define AUTH_REQ_SSPI      9   /* SSPI negotiate without wrap() */
+#define AUTH_REQ_SASL     10   /* SASL authentication. Not supported before
+                                * libpq version 10. */
 
 typedef uint32 AuthRequest;
 

diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index de94a9ec914958bb2de037346420281b2980e5b4..99285d9a8d56270c7405382b7d85e294a6b69a96 100644 (file)
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -703,6 +703,19 @@ pg_fe_sendauth(AuthRequest areq, PGconn *conn)
                return STATUS_ERROR;
            break;
 
+           /*
+            * SASL authentication was introduced in version 10. Older
+            * versions recognize the request only to give a nicer error
+            * message. We call it "SCRAM authentication" in the error, rather
+            * than SASL, because SCRAM is more familiar to users, and it's
+            * the only SASL authentication mechanism that has been
+            * implemented as of this writing, anyway.
+            */
+       case AUTH_REQ_SASL:
+           printfPQExpBuffer(&conn->errorMessage,
+                             libpq_gettext("SCRAM authentication requires libpq version 10 or above\n"));
+           return STATUS_ERROR;
+
        default:
            printfPQExpBuffer(&conn->errorMessage,
            libpq_gettext("authentication method %u not supported\n"), areq);