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authorSteffen Klassert <steffen.klassert@secunet.com>2017-12-08 08:07:25 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-25 11:05:49 +0100
commit9a54c510014b3a1d24d6a2e13dbb6a2eacb5a46c (patch)
tree5c471347eb7d1892c45440c86a3b393581c54a36
parent5ae4f528030800598c91cd1e814997d6284ca2c1 (diff)
xfrm: Fix stack-out-of-bounds with misconfigured transport mode policies.
[ Upstream commit 732706afe1cc46ef48493b3d2b69c98f36314ae4 ] On policies with a transport mode template, we pass the addresses from the flowi to xfrm_state_find(), assuming that the IP addresses (and address family) don't change during transformation. Unfortunately our policy template validation is not strict enough. It is possible to configure policies with transport mode template where the address family of the template does not match the selectors address family. This lead to stack-out-of-bound reads because we compare arddesses of the wrong family. Fix this by refusing such a configuration, address family can not change on transport mode. We use the assumption that, on transport mode, the first templates address family must match the address family of the policy selector. Subsequent transport mode templates must mach the address family of the previous template. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/xfrm/xfrm_user.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 4b52314c46d5..5d33967d9aa1 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1380,11 +1380,14 @@ static void copy_templates(struct xfrm_policy *xp, struct xfrm_user_tmpl *ut,
static int validate_tmpl(int nr, struct xfrm_user_tmpl *ut, u16 family)
{
+ u16 prev_family;
int i;
if (nr > XFRM_MAX_DEPTH)
return -EINVAL;
+ prev_family = family;
+
for (i = 0; i < nr; i++) {
/* We never validated the ut->family value, so many
* applications simply leave it at zero. The check was
@@ -1396,6 +1399,12 @@ static int validate_tmpl(int nr, struct xfrm_user_tmpl *ut, u16 family)
if (!ut[i].family)
ut[i].family = family;
+ if ((ut[i].mode == XFRM_MODE_TRANSPORT) &&
+ (ut[i].family != prev_family))
+ return -EINVAL;
+
+ prev_family = ut[i].family;
+
switch (ut[i].family) {
case AF_INET:
break;