xfrm: Validate address prefix lengths in the xfrm selector.

[ Upstream commit 07bf7908950a8b14e81aa1807e3c667eab39287a ]

We don't validate the address prefix lengths in the xfrm
selector we got from userspace. This can lead to undefined
behaviour in the address matching functions if the prefix
is too big for the given address family. Fix this by checking
the prefixes and refuse SA/policy insertation when a prefix
is invalid.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Air Icy <icytxw@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 5554d28a32eb10866b8403c7992b8209e3376a04..4292347bf45e71d43e7d571768885ad939dd99ca 100644 (file)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -151,10 +151,16 @@ static int verify_newsa_info(struct xfrm_usersa_info *p,
        err = -EINVAL;
        switch (p->family) {
        case AF_INET:
+               if (p->sel.prefixlen_d > 32 || p->sel.prefixlen_s > 32)
+                       goto out;
+
                break;
 
        case AF_INET6:
 #if IS_ENABLED(CONFIG_IPV6)
+               if (p->sel.prefixlen_d > 128 || p->sel.prefixlen_s > 128)
+                       goto out;
+
                break;
 #else
                err = -EAFNOSUPPORT;
@@ -1353,10 +1359,16 @@ static int verify_newpolicy_info(struct xfrm_userpolicy_info *p)
 
        switch (p->sel.family) {
        case AF_INET:
+               if (p->sel.prefixlen_d > 32 || p->sel.prefixlen_s > 32)
+                       return -EINVAL;
+
                break;
 
        case AF_INET6:
 #if IS_ENABLED(CONFIG_IPV6)
+               if (p->sel.prefixlen_d > 128 || p->sel.prefixlen_s > 128)
+                       return -EINVAL;
+
                break;
 #else
                return  -EAFNOSUPPORT;