Remove the use of the pg_auth flat file for client authentication.

(That flat file is now completely useless, but removal will come later.)

To do this, postpone client authentication into the startup transaction
that's run by InitPostgres.  We still collect the startup packet and do
SSL initialization (if needed) at the same time we did before.  The
AuthenticationTimeout is applied separately to startup packet collection
and the actual authentication cycle.  (This is a bit annoying, since it
means a couple extra syscalls; but the signal handling requirements inside
and outside a transaction are sufficiently different that it seems best
to treat the timeouts as completely independent.)

A small security disadvantage is that if the given database name is invalid,
this will be reported to the client before any authentication happens.
We could work around that by connecting to database "postgres" instead,
but consensus seems to be that it's not worth introducing such surprising
behavior.

Processing of all command-line switches and GUC options received from the
client is now postponed until after authentication.  This means that
PostAuthDelay is much less useful than it used to be --- if you need to
investigate problems during InitPostgres you'll have to set PreAuthDelay
instead.  However, allowing an unauthenticated user to set any GUC options
whatever seems a bit too risky, so we'll live with that.

1 files changed, 20 insertions, 20 deletions

diff --git a/src/backend/libpq/pqsignal.c b/src/backend/libpq/pqsignal.c
index ed26fbdb512..a6f0e109cf9 100644
--- a/src/backend/libpq/pqsignal.c
+++ b/src/backend/libpq/pqsignal.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/pqsignal.c,v 1.45 2009/01/01 17:23:42 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/pqsignal.c,v 1.46 2009/08/29 19:26:51 tgl Exp $
  *
  * NOTES
  *		This shouldn't be in libpq, but the monitor and some other
@@ -49,23 +49,23 @@
 #ifdef HAVE_SIGPROCMASK
 sigset_t	UnBlockSig,
 			BlockSig,
-			AuthBlockSig;
+			StartupBlockSig;
 #else
 int			UnBlockSig,
 			BlockSig,
-			AuthBlockSig;
+			StartupBlockSig;
 #endif
 
 
 /*
- * Initialize BlockSig, UnBlockSig, and AuthBlockSig.
+ * Initialize BlockSig, UnBlockSig, and StartupBlockSig.
  *
  * BlockSig is the set of signals to block when we are trying to block
  * signals.  This includes all signals we normally expect to get, but NOT
  * signals that should never be turned off.
  *
- * AuthBlockSig is the set of signals to block during authentication;
- * it's essentially BlockSig minus SIGTERM, SIGQUIT, SIGALRM.
+ * StartupBlockSig is the set of signals to block during startup packet
+ * collection; it's essentially BlockSig minus SIGTERM, SIGQUIT, SIGALRM.
  *
  * UnBlockSig is the set of signals to block when we don't want to block
  * signals (is this ever nonzero??)
@@ -79,7 +79,7 @@ pqinitmask(void)
 
 	/* First set all signals, then clear some. */
 	sigfillset(&BlockSig);
-	sigfillset(&AuthBlockSig);
+	sigfillset(&StartupBlockSig);
 
 	/*
 	 * Unmark those signals that should never be blocked. Some of these signal
@@ -88,46 +88,46 @@ pqinitmask(void)
 	 */
 #ifdef SIGTRAP
 	sigdelset(&BlockSig, SIGTRAP);
-	sigdelset(&AuthBlockSig, SIGTRAP);
+	sigdelset(&StartupBlockSig, SIGTRAP);
 #endif
 #ifdef SIGABRT
 	sigdelset(&BlockSig, SIGABRT);
-	sigdelset(&AuthBlockSig, SIGABRT);
+	sigdelset(&StartupBlockSig, SIGABRT);
 #endif
 #ifdef SIGILL
 	sigdelset(&BlockSig, SIGILL);
-	sigdelset(&AuthBlockSig, SIGILL);
+	sigdelset(&StartupBlockSig, SIGILL);
 #endif
 #ifdef SIGFPE
 	sigdelset(&BlockSig, SIGFPE);
-	sigdelset(&AuthBlockSig, SIGFPE);
+	sigdelset(&StartupBlockSig, SIGFPE);
 #endif
 #ifdef SIGSEGV
 	sigdelset(&BlockSig, SIGSEGV);
-	sigdelset(&AuthBlockSig, SIGSEGV);
+	sigdelset(&StartupBlockSig, SIGSEGV);
 #endif
 #ifdef SIGBUS
 	sigdelset(&BlockSig, SIGBUS);
-	sigdelset(&AuthBlockSig, SIGBUS);
+	sigdelset(&StartupBlockSig, SIGBUS);
 #endif
 #ifdef SIGSYS
 	sigdelset(&BlockSig, SIGSYS);
-	sigdelset(&AuthBlockSig, SIGSYS);
+	sigdelset(&StartupBlockSig, SIGSYS);
 #endif
 #ifdef SIGCONT
 	sigdelset(&BlockSig, SIGCONT);
-	sigdelset(&AuthBlockSig, SIGCONT);
+	sigdelset(&StartupBlockSig, SIGCONT);
 #endif
 
-/* Signals unique to Auth */
+/* Signals unique to startup */
 #ifdef SIGQUIT
-	sigdelset(&AuthBlockSig, SIGQUIT);
+	sigdelset(&StartupBlockSig, SIGQUIT);
 #endif
 #ifdef SIGTERM
-	sigdelset(&AuthBlockSig, SIGTERM);
+	sigdelset(&StartupBlockSig, SIGTERM);
 #endif
 #ifdef SIGALRM
-	sigdelset(&AuthBlockSig, SIGALRM);
+	sigdelset(&StartupBlockSig, SIGALRM);
 #endif
 #else
 	/* Set the signals we want. */
@@ -139,7 +139,7 @@ pqinitmask(void)
 		sigmask(SIGINT) | sigmask(SIGUSR1) |
 		sigmask(SIGUSR2) | sigmask(SIGCHLD) |
 		sigmask(SIGWINCH) | sigmask(SIGFPE);
-	AuthBlockSig = sigmask(SIGHUP) |
+	StartupBlockSig = sigmask(SIGHUP) |
 		sigmask(SIGINT) | sigmask(SIGUSR1) |
 		sigmask(SIGUSR2) | sigmask(SIGCHLD) |
 		sigmask(SIGWINCH) | sigmask(SIGFPE);