From 4f4061b2dde178d2ab79d1ee3b1ae3c62c117926 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Mon, 21 Oct 2019 11:17:13 +0900
Subject: [PATCH] Fix parsing of integer values for connection parameters in
 libpq

Commit e7a2217 has introduced stricter checks for integer values in
connection parameters for libpq.  However this failed to correctly check
after trailing whitespaces, while leading whitespaces were discarded per
the use of strtol(3).  This fixes and refactors the parsing logic to
handle both cases consistently.  Note that trying to restrict the use of
trailing whitespaces can easily break connection strings like in ECPG
regression tests (these have allowed me to catch the parsing bug with
connect_timeout).

Author: Michael Paquier
Reviewed-by: Lars Kanis
Discussion: https://postgr.es/m/a9b4cbd7-4ecb-06b2-ebd7-1739bbff3217@greiz-reinsdorf.de
Backpatch-through: 12
---
 src/interfaces/libpq/fe-connect.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index f91f0f2efe..e02564420c 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -1687,7 +1687,7 @@ useKeepalives(PGconn *conn)
 /*
  * Parse and try to interpret "value" as an integer value, and if successful,
  * store it in *result, complaining if there is any trailing garbage or an
- * overflow.
+ * overflow.  This allows any number of leading and trailing whitespaces.
  */
 static bool
 parse_int_param(const char *value, int *result, PGconn *conn,
@@ -1698,14 +1698,31 @@ parse_int_param(const char *value, int *result, PGconn *conn,
 
 	*result = 0;
 
+	/* strtol(3) skips leading whitespaces */
 	errno = 0;
 	numval = strtol(value, &end, 10);
-	if (errno == 0 && *end == '\0' && numval == (int) numval)
-	{
-		*result = numval;
-		return true;
-	}
 
+	/*
+	 * If no progress was done during the parsing or an error happened, fail.
+	 * This tests properly for overflows of the result.
+	 */
+	if (value == end || errno != 0 || numval != (int) numval)
+		goto error;
+
+	/*
+	 * Skip any trailing whitespace; if anything but whitespace remains before
+	 * the terminating character, fail
+	 */
+	while (*end && *end != '\0' && isspace((unsigned char) *end))
+		end++;
+
+	if (*end && *end != '\0')
+		goto error;
+
+	*result = numval;
+	return true;
+
+error:
 	appendPQExpBuffer(&conn->errorMessage,
 					  libpq_gettext("invalid integer value \"%s\" for connection option \"%s\"\n"),
 					  value, context);