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freebsd
GitHub Repository: freebsd/freebsd-doc
 Path: blob/main/website/static/security/patches/EN-08:02/tcp.patch
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Index: sys/netinet/tcp.h

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===================================================================

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RCS file: /home/ncvs/src/sys/netinet/tcp.h,v

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retrieving revision 1.40

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diff -p -u -I__FBSDID -I$FreeBSD -r1.40 tcp.h

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--- sys/netinet/tcp.h	25 May 2007 21:28:49 -0000	1.40

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+++ sys/netinet/tcp.h	18 Jun 2008 05:36:20 -0000

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@@ -78,6 +78,8 @@ struct tcphdr {

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 #define	TCPOPT_EOL		0

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 #define	   TCPOLEN_EOL			1

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+#define	TCPOPT_PAD		0		/* padding after EOL */

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+#define	   TCPOLEN_PAD			1

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 #define	TCPOPT_NOP		1

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 #define	   TCPOLEN_NOP			1

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 #define	TCPOPT_MAXSEG		2

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Index: sys/netinet/tcp_output.c

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===================================================================

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RCS file: /home/ncvs/src/sys/netinet/tcp_output.c,v

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retrieving revision 1.141.2.3

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diff -p -u -I__FBSDID -I$FreeBSD -r1.141.2.3 tcp_output.c

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--- sys/netinet/tcp_output.c	5 Dec 2007 10:37:17 -0000	1.141.2.3

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+++ sys/netinet/tcp_output.c	18 Jun 2008 05:36:21 -0000

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@@ -1280,12 +1280,16 @@ tcp_addoptions(struct tcpopt *to, u_char

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 	for (mask = 1; mask < TOF_MAXOPT; mask <<= 1) {

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 		if ((to->to_flags & mask) != mask)

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 			continue;

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+		if (optlen == TCP_MAXOLEN)

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+			break;

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 		switch (to->to_flags & mask) {

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 		case TOF_MSS:

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 			while (optlen % 4) {

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 				optlen += TCPOLEN_NOP;

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 				*optp++ = TCPOPT_NOP;

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 			}

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+			if (TCP_MAXOLEN - optlen < TCPOLEN_MAXSEG)

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+				continue;

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 			optlen += TCPOLEN_MAXSEG;

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 			*optp++ = TCPOPT_MAXSEG;

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 			*optp++ = TCPOLEN_MAXSEG;

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@@ -1298,6 +1302,8 @@ tcp_addoptions(struct tcpopt *to, u_char

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 				optlen += TCPOLEN_NOP;

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 				*optp++ = TCPOPT_NOP;

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 			}

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+			if (TCP_MAXOLEN - optlen < TCPOLEN_WINDOW)

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+				continue;

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 			optlen += TCPOLEN_WINDOW;

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 			*optp++ = TCPOPT_WINDOW;

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 			*optp++ = TCPOLEN_WINDOW;

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@@ -1308,6 +1314,8 @@ tcp_addoptions(struct tcpopt *to, u_char

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 				optlen += TCPOLEN_NOP;

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 				*optp++ = TCPOPT_NOP;

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 			}

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+			if (TCP_MAXOLEN - optlen < TCPOLEN_SACK_PERMITTED)

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+				continue;

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 			optlen += TCPOLEN_SACK_PERMITTED;

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 			*optp++ = TCPOPT_SACK_PERMITTED;

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 			*optp++ = TCPOLEN_SACK_PERMITTED;

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@@ -1317,6 +1325,8 @@ tcp_addoptions(struct tcpopt *to, u_char

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 				optlen += TCPOLEN_NOP;

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 				*optp++ = TCPOPT_NOP;

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 			}

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+			if (TCP_MAXOLEN - optlen < TCPOLEN_TIMESTAMP)

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+				continue;

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 			optlen += TCPOLEN_TIMESTAMP;

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 			*optp++ = TCPOPT_TIMESTAMP;

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 			*optp++ = TCPOLEN_TIMESTAMP;

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@@ -1355,7 +1365,7 @@ tcp_addoptions(struct tcpopt *to, u_char

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 				optlen += TCPOLEN_NOP;

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 				*optp++ = TCPOPT_NOP;

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 			}

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-			if (TCP_MAXOLEN - optlen < 2 + TCPOLEN_SACK)

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+			if (TCP_MAXOLEN - optlen < TCPOLEN_SACKHDR + TCPOLEN_SACK)

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 				continue;

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 			optlen += TCPOLEN_SACKHDR;

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 			*optp++ = TCPOPT_SACK;

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@@ -1386,9 +1396,15 @@ tcp_addoptions(struct tcpopt *to, u_char

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 		optlen += TCPOLEN_EOL;

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 		*optp++ = TCPOPT_EOL;

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 	}

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+	/*

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+	 * According to RFC 793 (STD0007):

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+	 *   "The content of the header beyond the End-of-Option option

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+	 *    must be header padding (i.e., zero)."

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+	 *   and later: "The padding is composed of zeros."

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+	 */

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 	while (optlen % 4) {

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-		optlen += TCPOLEN_NOP;

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-		*optp++ = TCPOPT_NOP;

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+		optlen += TCPOLEN_PAD;

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+		*optp++ = TCPOPT_PAD;

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 	}

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 	KASSERT(optlen <= TCP_MAXOLEN, ("%s: TCP options too long", __func__));

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