From ddf927fb13471bec0cc76794eaf552df8a1178fb Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 13 May 2019 10:53:19 -0400 Subject: [PATCH] Fix misuse of an integer as a bool. pgtls_read_pending is declared to return bool, but what the underlying SSL_pending function returns is a count of available bytes. This is actually somewhat harmless if we're using C99 bools, but in the back branches it's a live bug: if the available-bytes count happened to be a multiple of 256, it would get converted to a zero char value. On machines where char is signed, counts of 128 and up could misbehave as well. The net effect is that when using SSL, libpq might block waiting for data even though some has already been received. Broken by careless refactoring in commit 4e86f1b16, so back-patch to 9.5 where that came in. Per bug #15802 from David Binderman. Discussion: https://postgr.es/m/15802-f0911a97f0346526@postgresql.org --- src/interfaces/libpq/fe-misc.c | 2 +- src/interfaces/libpq/fe-secure-openssl.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c index ea4c9d2ee0c..f8786ebe9c8 100644 --- a/src/interfaces/libpq/fe-misc.c +++ b/src/interfaces/libpq/fe-misc.c @@ -1094,7 +1094,7 @@ pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time) #ifdef USE_SSL /* Check for SSL library buffering read bytes */ - if (forRead && conn->ssl_in_use && pgtls_read_pending(conn) > 0) + if (forRead && conn->ssl_in_use && pgtls_read_pending(conn)) { /* short-circuit the select */ return 1; diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c index f634c99ca60..b62b4969698 100644 --- a/src/interfaces/libpq/fe-secure-openssl.c +++ b/src/interfaces/libpq/fe-secure-openssl.c @@ -264,7 +264,7 @@ rloop: bool pgtls_read_pending(PGconn *conn) { - return SSL_pending(conn->ssl); + return SSL_pending(conn->ssl) > 0; } ssize_t