From 8723db212b448269de3734dd4055242155f0129b Mon Sep 17 00:00:00 2001
From: "Simon L. B. Nielsen" <simon@FreeBSD.org>
Date: Sat, 30 Sep 2006 19:58:07 +0000
Subject: Correct multiple vulnerabilities in OpenSSH.

Security:	FreeBSD-SA-06:22.openssh
Approved by:	so (simon)
---
 UPDATING                     |  3 +++
 crypto/openssh/auth.h        |  1 +
 crypto/openssh/deattack.c    | 24 ++++++++++++++++++++++--
 crypto/openssh/deattack.h    |  1 +
 crypto/openssh/defines.h     |  5 +++++
 crypto/openssh/log.c         | 14 ++++++++++++++
 crypto/openssh/log.h         |  1 +
 crypto/openssh/packet.c      | 13 ++++++++++---
 crypto/openssh/session.c     |  2 +-
 crypto/openssh/ssh_config    |  2 +-
 crypto/openssh/ssh_config.5  |  2 +-
 crypto/openssh/sshd.c        |  4 +++-
 crypto/openssh/sshd_config   |  2 +-
 crypto/openssh/sshd_config.5 |  2 +-
 crypto/openssh/version.h     |  2 +-
 sys/conf/newvers.sh          |  2 +-
 16 files changed, 67 insertions(+), 13 deletions(-)

diff --git a/UPDATING b/UPDATING
index 9fdb427036bb..128f241f5045 100644
--- a/UPDATING
+++ b/UPDATING
@@ -8,6 +8,9 @@ Items affecting the ports and packages system can be found in
 /usr/ports/UPDATING.  Please read that file before running
 portupgrade.  Important recent entries: 20040724 (default X changes).
 
+20060930:	p37	FreeBSD-SA-06:22.openssh
+	Correct multiple vulnerabilities in sshd(8).
+
 20060929:	p36	FreeBSD-SA-06:23.openssl
 	Correct problem in the 2006-09-28 patch concerning the handling of
 	excessively large DH moduli.
diff --git a/crypto/openssh/auth.h b/crypto/openssh/auth.h
index 83841b6591aa..1edc516ac518 100644
--- a/crypto/openssh/auth.h
+++ b/crypto/openssh/auth.h
@@ -49,6 +49,7 @@ typedef struct KbdintDevice KbdintDevice;
 
 struct Authctxt {
 	int		 success;
+	int		 authenticated;	/* authenticated and alarms cancelled */
 	int		 postponed;	/* authentication needs another step */
 	int		 valid;		/* user exists and is allowed to login */
 	int		 attempt;
diff --git a/crypto/openssh/deattack.c b/crypto/openssh/deattack.c
index 8b55d668681a..1ed12a01ab70 100644
--- a/crypto/openssh/deattack.c
+++ b/crypto/openssh/deattack.c
@@ -27,6 +27,24 @@ RCSID("$OpenBSD: deattack.c,v 1.19 2003/09/18 08:49:45 markus Exp $");
 #include "xmalloc.h"
 #include "deattack.h"
 
+/*
+ * CRC attack detection has a worst-case behaviour that is O(N^3) over
+ * the number of identical blocks in a packet. This behaviour can be 
+ * exploited to create a limited denial of service attack. 
+ * 
+ * However, because we are dealing with encrypted data, identical
+ * blocks should only occur every 2^35 maximally-sized packets or so. 
+ * Consequently, we can detect this DoS by looking for identical blocks
+ * in a packet.
+ *
+ * The parameter below determines how many identical blocks we will
+ * accept in a single packet, trading off between attack detection and
+ * likelihood of terminating a legitimate connection. A value of 32 
+ * corresponds to an average of 2^40 messages before an attack is
+ * misdetected
+ */
+#define MAX_IDENTICAL	32
+
 /* SSH Constants */
 #define SSH_MAXBLOCKS	(32 * 1024)
 #define SSH_BLOCKSIZE	(8)
@@ -87,7 +105,7 @@ detect_attack(u_char *buf, u_int32_t len, u_char *IV)
 	static u_int16_t *h = (u_int16_t *) NULL;
 	static u_int32_t n = HASH_MINSIZE / HASH_ENTRYSIZE;
 	u_int32_t i, j;
-	u_int32_t l;
+	u_int32_t l, same;
 	u_char *c;
 	u_char *d;
 
@@ -133,7 +151,7 @@ detect_attack(u_char *buf, u_int32_t len, u_char *IV)
 	if (IV)
 		h[HASH(IV) & (n - 1)] = HASH_IV;
 
-	for (c = buf, j = 0; c < (buf + len); c += SSH_BLOCKSIZE, j++) {
+	for (c = buf, same = j = 0; c < (buf + len); c += SSH_BLOCKSIZE, j++) {
 		for (i = HASH(c) & (n - 1); h[i] != HASH_UNUSED;
 		    i = (i + 1) & (n - 1)) {
 			if (h[i] == HASH_IV) {
@@ -144,6 +162,8 @@ detect_attack(u_char *buf, u_int32_t len, u_char *IV)
 						break;
 				}
 			} else if (!CMP(c, buf + h[i] * SSH_BLOCKSIZE)) {
+				if (++same > MAX_IDENTICAL)
+					return (DEATTACK_DOS_DETECTED);
 				if (check_crc(c, buf, len, IV))
 					return (DEATTACK_DETECTED);
 				else
diff --git a/crypto/openssh/deattack.h b/crypto/openssh/deattack.h
index ddccdea50594..cd3d7aa3b5a7 100644
--- a/crypto/openssh/deattack.h
+++ b/crypto/openssh/deattack.h
@@ -25,6 +25,7 @@
 /* Return codes */
 #define DEATTACK_OK		0
 #define DEATTACK_DETECTED	1
+#define DEATTACK_DOS_DETECTED	2
 
 int	 detect_attack(u_char *, u_int32_t, u_char[8]);
 #endif
diff --git a/crypto/openssh/defines.h b/crypto/openssh/defines.h
index 9b72afecb43c..01b55d580285 100644
--- a/crypto/openssh/defines.h
+++ b/crypto/openssh/defines.h
@@ -511,6 +511,11 @@ struct winsize {
 # undef HAVE_UPDWTMPX
 #endif
 
+#if defined(HAVE_OPENLOG_R) && defined(SYSLOG_DATA_INIT) && \
+    defined(SYSLOG_R_SAFE_IN_SIGHAND)
+# define DO_LOG_SAFE_IN_SIGHAND
+#endif
+
 #if !defined(HAVE_MEMMOVE) && defined(HAVE_BCOPY)
 # define memmove(s1, s2, n) bcopy((s2), (s1), (n))
 #endif /* !defined(HAVE_MEMMOVE) && defined(HAVE_BCOPY) */
diff --git a/crypto/openssh/log.c b/crypto/openssh/log.c
index 0c4d5123a63b..36d2f54437a0 100644
--- a/crypto/openssh/log.c
+++ b/crypto/openssh/log.c
@@ -127,6 +127,20 @@ error(const char *fmt,...)
 	va_end(args);
 }
 
+void
+sigdie(const char *fmt,...)
+{
+	va_list args;
+
+#ifdef DO_LOG_SAFE_IN_SIGHAND
+	va_start(args, fmt);
+	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
+	va_end(args);
+#endif
+	_exit(1);
+}
+
+
 /* Log this message (information that usually should go to the log). */
 
 void
diff --git a/crypto/openssh/log.h b/crypto/openssh/log.h
index ca4d7bf6da97..73ca3c25200f 100644
--- a/crypto/openssh/log.h
+++ b/crypto/openssh/log.h
@@ -64,6 +64,7 @@ LogLevel log_level_number(char *);
 
 void     fatal(const char *, ...) __attribute__((format(printf, 1, 2)));
 void     error(const char *, ...) __attribute__((format(printf, 1, 2)));
+void     sigdie(const char *, ...) __attribute__((format(printf, 1, 2)));
 void     logit(const char *, ...) __attribute__((format(printf, 1, 2)));
 void     verbose(const char *, ...) __attribute__((format(printf, 1, 2)));
 void     debug(const char *, ...) __attribute__((format(printf, 1, 2)));
diff --git a/crypto/openssh/packet.c b/crypto/openssh/packet.c
index daae9ffaaa2a..bd1bceccccdd 100644
--- a/crypto/openssh/packet.c
+++ b/crypto/openssh/packet.c
@@ -940,9 +940,16 @@ packet_read_poll1(void)
 	 * (C)1998 CORE-SDI, Buenos Aires Argentina
 	 * Ariel Futoransky(futo@core-sdi.com)
 	 */
-	if (!receive_context.plaintext &&
-	    detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
-		packet_disconnect("crc32 compensation attack: network attack detected");
+	if (!receive_context.plaintext) {
+		switch (detect_attack(buffer_ptr(&input), padded_len, NULL)) {
+		case DEATTACK_DETECTED:
+			packet_disconnect("crc32 compensation attack: "
+			    "network attack detected");
+		case DEATTACK_DOS_DETECTED:
+			packet_disconnect("deattack denial of "
+			    "service detected");
+		}
+	}
 
 	/* Decrypt data to incoming_packet. */
 	buffer_clear(&incoming_packet);
diff --git a/crypto/openssh/session.c b/crypto/openssh/session.c
index 3f9049f3593e..bcf5b6df4e97 100644
--- a/crypto/openssh/session.c
+++ b/crypto/openssh/session.c
@@ -2266,7 +2266,7 @@ do_cleanup(Authctxt *authctxt)
 		return;
 	called = 1;
 
-	if (authctxt == NULL)
+	if (authctxt == NULL || !authctxt->authenticated)
 		return;
 #ifdef KRB5
 	if (options.kerberos_ticket_cleanup &&
diff --git a/crypto/openssh/ssh_config b/crypto/openssh/ssh_config
index 2ca4469fec6d..0ca3060ba233 100644
--- a/crypto/openssh/ssh_config
+++ b/crypto/openssh/ssh_config
@@ -36,4 +36,4 @@
 #   Cipher 3des
 #   Ciphers aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc
 #   EscapeChar ~
-#   VersionAddendum FreeBSD-20060123
+#   VersionAddendum FreeBSD-20060930
diff --git a/crypto/openssh/ssh_config.5 b/crypto/openssh/ssh_config.5
index e74530b42422..3e89c9c04006 100644
--- a/crypto/openssh/ssh_config.5
+++ b/crypto/openssh/ssh_config.5
@@ -719,7 +719,7 @@ Note that this option applies to protocol version 2 only.
 Specifies a string to append to the regular version string to identify
 OS- or site-specific modifications.
 The default is
-.Dq FreeBSD-20060123 .
+.Dq FreeBSD-20060930 .
 .It Cm XAuthLocation
 Specifies the full pathname of the
 .Xr xauth 1
diff --git a/crypto/openssh/sshd.c b/crypto/openssh/sshd.c
index 22c2e3d0a535..54a374a7dad0 100644
--- a/crypto/openssh/sshd.c
+++ b/crypto/openssh/sshd.c
@@ -314,7 +314,7 @@ grace_alarm_handler(int sig)
 		kill(pmonitor->m_pid, SIGALRM);
 
 	/* Log error and exit. */
-	fatal("Timeout before authentication for %s", get_remote_ipaddr());
+	sigdie("Timeout before authentication for %s", get_remote_ipaddr());
 }
 
 /*
@@ -1509,6 +1509,8 @@ main(int ac, char **av)
 	}
 
  authenticated:
+	authctxt->authenticated = 1;
+
 	/*
 	 * In privilege separation, we fork another child and prepare
 	 * file descriptor passing.
diff --git a/crypto/openssh/sshd_config b/crypto/openssh/sshd_config
index 77816ba38051..d701370a97a2 100644
--- a/crypto/openssh/sshd_config
+++ b/crypto/openssh/sshd_config
@@ -14,7 +14,7 @@
 # Note that some of FreeBSD's defaults differ from OpenBSD's, and
 # FreeBSD has a few additional options.
 
-#VersionAddendum FreeBSD-20060123
+#VersionAddendum FreeBSD-20060930
 
 #Port 22
 #Protocol 2
diff --git a/crypto/openssh/sshd_config.5 b/crypto/openssh/sshd_config.5
index d13c72935228..fff5d4121b9b 100644
--- a/crypto/openssh/sshd_config.5
+++ b/crypto/openssh/sshd_config.5
@@ -660,7 +660,7 @@ The default is
 Specifies a string to append to the regular version string to identify
 OS- or site-specific modifications.
 The default is
-.Dq FreeBSD-20060123 .
+.Dq FreeBSD-20060930 .
 .It Cm X11DisplayOffset
 Specifies the first display number available for
 .Nm sshd Ns 's
diff --git a/crypto/openssh/version.h b/crypto/openssh/version.h
index cac15808b53d..372cc49a8a45 100644
--- a/crypto/openssh/version.h
+++ b/crypto/openssh/version.h
@@ -5,7 +5,7 @@
 
 #define SSH_VERSION             (ssh_version_get())
 #define SSH_VERSION_BASE        "OpenSSH_3.8.1p1"
-#define SSH_VERSION_ADDENDUM    "FreeBSD-20060123"
+#define SSH_VERSION_ADDENDUM    "FreeBSD-20060930"
 
 const char *ssh_version_get(void);
 void ssh_version_set_addendum(const char *add);
diff --git a/sys/conf/newvers.sh b/sys/conf/newvers.sh
index 01c8caed7f29..6b6581943d1b 100644
--- a/sys/conf/newvers.sh
+++ b/sys/conf/newvers.sh
@@ -32,7 +32,7 @@
 
 TYPE="FreeBSD"
 REVISION="5.3"
-BRANCH="RELEASE-p36"
+BRANCH="RELEASE-p37"
 RELEASE="${REVISION}-${BRANCH}"
 VERSION="${TYPE} ${RELEASE}"
 
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