xfrm: Fix xfrm_input() to verify state is valid when (encap_type < 0)

[ Upstream commit 4ce3dbe ]

Code path when (encap_type < 0) does not verify the state is valid
before progressing.

This will result in a crash if, for instance, x->km.state ==
XFRM_STATE_ACQ.

Fixes: 7785bba ("esp: Add a software GRO codepath")
Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/xfrm/xfrm_input.c

@@ -207,7 +207,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
  xfrm_address_t *daddr;
  struct xfrm_mode *inner_mode;
  u32 mark = skb->mark;
- unsigned int family;
+ unsigned int family = AF_UNSPEC;
  int decaps = 0;
  int async = 0;
  bool xfrm_gro = false;
@@ -216,6 +216,16 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 
  if (encap_type < 0) {
  x = xfrm_input_state(skb);
+
+ if (unlikely(x->km.state != XFRM_STATE_VALID)) {
+ if (x->km.state == XFRM_STATE_ACQ)
+ XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
+ else
+ XFRM_INC_STATS(net,
+ LINUX_MIB_XFRMINSTATEINVALID);
+ goto drop;
+ }
+
  family = x->outer_mode->afinfo->family;
 
  /* An encap_type of -1 indicates async resumption. */