Add missing bad-PGconn guards in libpq entry points.

tglsfdc · tglsfdc · commit ef9f35964dea · 2022-08-15T15:40:07.000-04:00
There's a convention that externally-visible libpq functions should check for a NULL PGconn pointer, and fail gracefully instead of crashing. PQflush() and PQisnonblocking() didn't get that memo though. Also add a similar check to PQdefaultSSLKeyPassHook_OpenSSL; while it's not clear that ordinary usage could reach that with a null conn pointer, it's cheap enough to check, so let's be consistent. Daniele Varrazzo and Tom Lane Discussion: https://postgr.es/m/CA+mi_8Zm_mVVyW1iNFgyMd9Oh0Nv8-F+7Y3-BqwMgTMHuo_h2Q@mail.gmail.com
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
@@ -3922,6 +3922,8 @@ PQsetnonblocking(PGconn *conn, int arg)
 int
 PQisnonblocking(const PGconn *conn)
 {
+	if (!conn || conn->status == CONNECTION_BAD)
+		return false;
 	return pqIsnonblocking(conn);
 }
 
@@ -3941,6 +3943,8 @@ PQisthreadsafe(void)
 int
 PQflush(PGconn *conn)
 {
+	if (!conn || conn->status == CONNECTION_BAD)
+		return -1;
 	return pqFlush(conn);
 }
 
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
@@ -1938,7 +1938,7 @@ my_SSL_set_fd(PGconn *conn, int fd)
 int
 PQdefaultSSLKeyPassHook_OpenSSL(char *buf, int size, PGconn *conn)
 {
-	if (conn->sslpassword)
+	if (conn && conn->sslpassword)
 	{
 		if (strlen(conn->sslpassword) + 1 > size)
 			fprintf(stderr, libpq_gettext("WARNING: sslpassword truncated\n"));

Original file line number	Diff line number	Diff line change
`@@ -3922,6 +3922,8 @@ PQsetnonblocking(PGconn *conn, int arg)`
`3922`	`3922`	`int`
`3923`	`3923`	`PQisnonblocking(const PGconn *conn)`
`3924`	`3924`	`{`
	`3925`	`+ if (!conn \|\| conn->status == CONNECTION_BAD)`
	`3926`	`+ return false;`
`3925`	`3927`	`return pqIsnonblocking(conn);`
`3926`	`3928`	`}`
`3927`	`3929`
`@@ -3941,6 +3943,8 @@ PQisthreadsafe(void)`
`3941`	`3943`	`int`
`3942`	`3944`	`PQflush(PGconn *conn)`
`3943`	`3945`	`{`
	`3946`	`+ if (!conn \|\| conn->status == CONNECTION_BAD)`
	`3947`	`+ return -1;`
`3944`	`3948`	`return pqFlush(conn);`
`3945`	`3949`	`}`
`3946`	`3950`
Original file line number	Diff line number	Diff line change
`@@ -1938,7 +1938,7 @@ my_SSL_set_fd(PGconn *conn, int fd)`
`1938`	`1938`	`int`
`1939`	`1939`	`PQdefaultSSLKeyPassHook_OpenSSL(char buf, int size, PGconn conn)`
`1940`	`1940`	`{`
`1941`		`- if (conn->sslpassword)`
	`1941`	`+ if (conn && conn->sslpassword)`
`1942`	`1942`	`{`
`1943`	`1943`	`if (strlen(conn->sslpassword) + 1 > size)`
`1944`	`1944`	`fprintf(stderr, libpq_gettext("WARNING: sslpassword truncated\n"));`