Don't allow immediate interrupts during authentication anymore.

We used to handle authentication_timeout by setting
ImmediateInterruptOK to true during large parts of the authentication
phase of a new connection.  While that happens to work acceptably in
practice, it's not particularly nice and has ugly corner cases.

Previous commits converted the FE/BE communication to use latches and
implemented support for interrupt handling during both
send/recv. Building on top of that work we can get rid of
ImmediateInterruptOK during authentication, by immediately treating
timeouts during authentication as a reason to die. As die interrupts
are handled immediately during client communication that provides a
sensibly quick reaction time to authentication timeout.

Additionally add a few CHECK_FOR_INTERRUPTS() to some more complex
authentication methods. More could be added, but this already should
provides a reasonable coverage.

While it this overall increases the maximum time till a timeout is
reacted to, it greatly reduces complexity and increases
reliability. That seems like a overall win. If the increase proves to
be noticeable we can deal with those cases by moving to nonblocking
network code and add interrupt checking there.

Reviewed-By: Heikki Linnakangas

1 files changed, 0 insertions, 10 deletions

diff --git a/src/backend/libpq/crypt.c b/src/backend/libpq/crypt.c
index 599b63a48b5..97be9443c04 100644
--- a/src/backend/libpq/crypt.c
+++ b/src/backend/libpq/crypt.c
@@ -47,13 +47,6 @@ md5_crypt_verify(const Port *port, const char *role, char *client_pass,
 	Datum		datum;
 	bool		isnull;
 
-	/*
-	 * Disable immediate interrupts while doing database access.  (Note we
-	 * don't bother to turn this back on if we hit one of the failure
-	 * conditions, since we can expect we'll just exit right away anyway.)
-	 */
-	ImmediateInterruptOK = false;
-
 	/* Get role info from pg_authid */
 	roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(role));
 	if (!HeapTupleIsValid(roleTup))
@@ -80,9 +73,6 @@ md5_crypt_verify(const Port *port, const char *role, char *client_pass,
 	if (*shadow_pass == '\0')
 		return STATUS_ERROR;	/* empty password */
 
-	/* Re-enable immediate response to SIGTERM/SIGINT/timeout interrupts */
-	ImmediateInterruptOK = true;
-	/* And don't forget to detect one that already arrived */
 	CHECK_FOR_INTERRUPTS();
 
 	/*