openssh: fix CVE-2010-5107

From http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2010-5107:
"The default configuration of OpenSSH through 6.1 enforces a fixed time limit
between establishing a TCP connection and completing a login, which makes it
easier for remote attackers to cause a denial of service (connection-slot
exhaustion) by periodically making many new TCP connections."

Integrate patches from upstream to enable "random early drop" by default./

(From OE-Core rev: 1d4f2d5ef65135e61d78ac0db90afe7f5d166d05)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 52 insertions, 1 deletions

diff --git a/meta/recipes-connectivity/openssh/openssh-6.0p1/cve-2010-5107.patch b/meta/recipes-connectivity/openssh/openssh-6.0p1/cve-2010-5107.patch
new file mode 100644
index 0000000000..148dc510c1
--- /dev/null
+++ b/meta/recipes-connectivity/openssh/openssh-6.0p1/cve-2010-5107.patch
@@ -0,0 +1,50 @@
+Fix CVE-2010-5107 by backporting the relevant changes from upstream CVS.
+
+http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/servconf.c?r1=1.234#rev1.234
+http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshd_config.5?r1=1.156#rev1.156
+http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshd_config?r1=1.89#rev1.89
+
+Upstream-Status: Backport
+Signed-off-by: Ross Burton <ross.burton@intel.com>
+
+--- a/src/usr.bin/ssh/sshd_config       2012/10/30 22:29:55     1.88
++++ b/src/usr.bin/ssh/sshd_config       2013/02/06 00:20:42     1.89
+@@ -96,7 +96,7 @@ UsePrivilegeSeparation sandbox                # Default for new inst
+ #ClientAliveCountMax 3
+ #UseDNS yes
+ #PidFile /var/run/sshd.pid
+-#MaxStartups 10
++#MaxStartups 10:30:100
+ #PermitTunnel no
+ #ChrootDirectory none
+ #VersionAddendum none
+
+--- a/src/usr.bin/ssh/sshd_config.5     2013/01/18 08:00:49     1.155
++++ b/src/usr.bin/ssh/sshd_config.5     2013/02/06 00:20:42     1.156
+@@ -821,7 +821,7 @@ SSH daemon.
+ Additional connections will be dropped until authentication succeeds or the
+ .Cm LoginGraceTime
+ expires for a connection.
+-The default is 10.
++The default is 10:30:100.
+ .Pp
+ Alternatively, random early drop can be enabled by specifying
+ the three colon separated values
+
+--- a/src/usr.bin/ssh/servconf.c        2012/12/02 20:46:11     1.233
++++ b/src/usr.bin/ssh/servconf.c        2013/02/06 00:20:42     1.234
+@@ -242,11 +242,11 @@ fill_default_server_options(ServerOptions *options)
+        if (options->gateway_ports == -1)
+                options->gateway_ports = 0;
+        if (options->max_startups == -1)
+-               options->max_startups = 10;
++               options->max_startups = 100;
+        if (options->max_startups_rate == -1)
+-               options->max_startups_rate = 100;               /* 100% */
++               options->max_startups_rate = 30;                /* 30% */
+        if (options->max_startups_begin == -1)
+-               options->max_startups_begin = options->max_startups;
++               options->max_startups_begin = 10;
+        if (options->max_authtries == -1)
+                options->max_authtries = DEFAULT_AUTH_FAIL_MAX;
+        if (options->max_sessions == -1)
diff --git a/meta/recipes-connectivity/openssh/openssh_6.0p1.bb b/meta/recipes-connectivity/openssh/openssh_6.0p1.bb
index 31202d4284..d1edb6ed04 100644
--- a/meta/recipes-connectivity/openssh/openssh_6.0p1.bb
+++ b/meta/recipes-connectivity/openssh/openssh_6.0p1.bb
@@ -23,7 +23,8 @@ SRC_URI = "ftp://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-${PV}.tar.
            file://sshd_config \
            file://ssh_config \
            file://init \
-           ${@base_contains('DISTRO_FEATURES', 'pam', '${PAM_SRC_URI}', '', d)}"
+           ${@base_contains('DISTRO_FEATURES', 'pam', '${PAM_SRC_URI}', '', d)} \
+           file://cve-2010-5107.patch;pnum=4"
 
 PAM_SRC_URI = "file://sshd"
 SRC_URI[md5sum] = "3c9347aa67862881c5da3f3b1c08da7b"