[pve-devel] applied: [PATCH kernel 1/2] fix CVE-2017-7184: local privilege escalation

[Fabian Grünbichler]

Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
---
 Makefile                                           |  2 +
 ...alidate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch | 51 ++++++++++++++++++++++
 ...alidate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch | 41 +++++++++++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 CVE-2017-7184-0001-xfrm_user-validate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch
 create mode 100644 CVE-2017-7184-0002-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch

diff --git a/Makefile b/Makefile
index 0c12009..5de9672 100644
--- a/Makefile
+++ b/Makefile
@@ -265,6 +265,8 @@ ${KERNEL_SRC}/README ${KERNEL_CFG_ORG}: ${KERNELSRCTAR}
 	cd ${KERNEL_SRC}; patch -p1 < ../cgroup-cpuset-add-cpuset.remap_cpus.patch
 	cd ${KERNEL_SRC}; patch -p1 < ../CVE-2017-2596-kvm-page-reference-leakage-in-handle_vmon.patch
 	cd ${KERNEL_SRC}; patch -p1 < ../Revert-intel_idle-Add-CPU-model-54-Atom-N2000-series.patch
+	cd ${KERNEL_SRC}; patch -p1 < ../CVE-2017-7184-0001-xfrm_user-validate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch
+	cd ${KERNEL_SRC}; patch -p1 < ../CVE-2017-7184-0002-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch
 	sed -i ${KERNEL_SRC}/Makefile -e 's/^EXTRAVERSION.*$$/EXTRAVERSION=${EXTRAVERSION}/'
 	touch $@
 
diff --git a/CVE-2017-7184-0001-xfrm_user-validate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch b/CVE-2017-7184-0001-xfrm_user-validate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch
new file mode 100644
index 0000000..369ee7e
--- /dev/null
+++ b/CVE-2017-7184-0001-xfrm_user-validate-XFRM_MSG_NEWAE-XFRMA_REPLAY_ESN_V.patch
@@ -0,0 +1,51 @@
+From 7f223b44260db3bd37b279534d287b76f2589fec Mon Sep 17 00:00:00 2001
+From: Andy Whitcroft <apw at canonical.com>
+Date: Wed, 22 Mar 2017 07:29:31 +0000
+Subject: [PATCH 1/2] xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL
+ replay_window
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When a new xfrm state is created during an XFRM_MSG_NEWSA call we
+validate the user supplied replay_esn to ensure that the size is valid
+and to ensure that the replay_window size is within the allocated
+buffer.  However later it is possible to update this replay_esn via a
+XFRM_MSG_NEWAE call.  There we again validate the size of the supplied
+buffer matches the existing state and if so inject the contents.  We do
+not at this point check that the replay_window is within the allocated
+memory.  This leads to out-of-bounds reads and writes triggered by
+netlink packets.  This leads to memory corruption and the potential for
+priviledge escalation.
+
+We already attempt to validate the incoming replay information in
+xfrm_new_ae() via xfrm_replay_verify_len().  This confirms that the user
+is not trying to change the size of the replay state buffer which
+includes the replay_esn.  It however does not check the replay_window
+remains within that buffer.  Add validation of the contained
+replay_window.
+
+CVE-2017-7184
+Signed-off-by: Andy Whitcroft <apw at canonical.com>
+Acked-by: Steffen Klassert <steffen.klassert at secunet.com>
+Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
+
+Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
+---
+ net/xfrm/xfrm_user.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
+index 805681a..0e1f833 100644
+--- a/net/xfrm/xfrm_user.c
++++ b/net/xfrm/xfrm_user.c
+@@ -415,6 +415,9 @@ static inline int xfrm_replay_verify_len(struct xfrm_replay_state_esn *replay_es
+ 	if (nla_len(rp) < ulen || xfrm_replay_state_esn_len(replay_esn) != ulen)
+ 		return -EINVAL;
+ 
++	if (up->replay_window > up->bmp_len * sizeof(__u32) * 8)
++		return -EINVAL;
++
+ 	return 0;
+ }
+ 
diff --git a/CVE-2017-7184-0002-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch b/CVE-2017-7184-0002-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch
new file mode 100644
index 0000000..db77d70
--- /dev/null
+++ b/CVE-2017-7184-0002-xfrm_user-validate-XFRM_MSG_NEWAE-incoming-ESN-size-.patch
@@ -0,0 +1,41 @@
+From 4e5d70856a6d11cb6c174c6a304a7ef3788e00be Mon Sep 17 00:00:00 2001
+From: Andy Whitcroft <apw at canonical.com>
+Date: Thu, 23 Mar 2017 07:45:44 +0000
+Subject: [PATCH 2/2] xfrm_user: validate XFRM_MSG_NEWAE incoming ESN size
+ harder
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Kees Cook has pointed out that xfrm_replay_state_esn_len() is subject to
+wrapping issues.  To ensure we are correctly ensuring that the two ESN
+structures are the same size compare both the overall size as reported
+by xfrm_replay_state_esn_len() and the internal length are the same.
+
+CVE-2017-7184
+Signed-off-by: Andy Whitcroft <apw at canonical.com>
+Acked-by: Steffen Klassert <steffen.klassert at secunet.com>
+Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
+
+Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
+---
+ net/xfrm/xfrm_user.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
+index 0e1f833..7a5a64e 100644
+--- a/net/xfrm/xfrm_user.c
++++ b/net/xfrm/xfrm_user.c
+@@ -412,7 +412,11 @@ static inline int xfrm_replay_verify_len(struct xfrm_replay_state_esn *replay_es
+ 	up = nla_data(rp);
+ 	ulen = xfrm_replay_state_esn_len(up);
+ 
+-	if (nla_len(rp) < ulen || xfrm_replay_state_esn_len(replay_esn) != ulen)
++	/* Check the overall length and the internal bitmap length to avoid
++	 * potential overflow. */
++	if (nla_len(rp) < ulen ||
++	    xfrm_replay_state_esn_len(replay_esn) != ulen ||
++	    replay_esn->bmp_len != up->bmp_len)
+ 		return -EINVAL;
+ 
+ 	if (up->replay_window > up->bmp_len * sizeof(__u32) * 8)
-- 
2.1.4