From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 8 Nov 2004 01:54:58 +0000 (+0000)
Subject: Fix unportable code in SockAddr_cidr_mask: you can't assume that
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=30f4f73a5cd9814fdf957611081237c4e6417326;p=users%2Fbernd%2Fpostgres.git

Fix unportable code in SockAddr_cidr_mask: you can't assume that
shifting left by full word width gives zero.  Per bug report from
Tyson Thomson.
---

diff --git a/src/backend/libpq/ip.c b/src/backend/libpq/ip.c
index bf7dac28b5..2356bcd319 100644
--- a/src/backend/libpq/ip.c
+++ b/src/backend/libpq/ip.c
@@ -344,37 +344,40 @@ SockAddr_cidr_mask(struct sockaddr_storage * mask, char *numbits, int family)
 {
 	long		bits;
 	char	   *endptr;
-	struct sockaddr_in mask4;
-
-#ifdef	HAVE_IPV6
-	struct sockaddr_in6 mask6;
-#endif
 
 	bits = strtol(numbits, &endptr, 10);
 
 	if (*numbits == '\0' || *endptr != '\0')
 		return -1;
 
-	if ((bits < 0) || (family == AF_INET && bits > 32)
-#ifdef HAVE_IPV6
-		|| (family == AF_INET6 && bits > 128)
-#endif
-		)
-		return -1;
-
 	switch (family)
 	{
 		case AF_INET:
-			mask4.sin_addr.s_addr =
-				htonl((0xffffffffUL << (32 - bits))
-					  & 0xffffffffUL);
-			memcpy(mask, &mask4, sizeof(mask4));
-			break;
+			{
+				struct sockaddr_in mask4;
+				long		maskl;
+
+				if (bits < 0 || bits > 32)
+					return -1;
+				/* avoid "x << 32", which is not portable */
+				if (bits > 0)
+					maskl = (0xffffffffUL << (32 - (int) bits))
+						& 0xffffffffUL;
+				else
+					maskl = 0;
+				mask4.sin_addr.s_addr = htonl(maskl);
+				memcpy(mask, &mask4, sizeof(mask4));
+				break;
+			}
+
 #ifdef HAVE_IPV6
 		case AF_INET6:
 			{
+				struct sockaddr_in6 mask6;
 				int			i;
 
+				if (bits < 0 || bits > 128)
+					return -1;
 				for (i = 0; i < 16; i++)
 				{
 					if (bits <= 0)
@@ -384,7 +387,7 @@ SockAddr_cidr_mask(struct sockaddr_storage * mask, char *numbits, int family)
 					else
 					{
 						mask6.sin6_addr.s6_addr[i] =
-							(0xff << (8 - bits)) & 0xff;
+							(0xff << (8 - (int) bits)) & 0xff;
 					}
 					bits -= 8;
 				}