Commit 7fcf9449 authored Jan 20, 2023 by Eric Dumazet Committed by Lee Jones May 04, 2023

UPSTREAM: xfrm/compat: prevent potential spectre v1 gadget in xfrm_xlate32_attr()



  int type = nla_type(nla);

  if (type > XFRMA_MAX) {
            return -EOPNOTSUPP;
  }

@type is then used as an array index and can be used
as a Spectre v1 gadget.

  if (nla_len(nla) < compat_policy[type].len) {

array_index_nospec() can be used to prevent leaking
content of kernel memory to malicious users.

Bug: 254441685
Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dmitry Safonov <dima@arista.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
(cherry picked from commit b6ee896385380aa621102e8ea402ba12db1cabff)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I7d3122e26c8ff3a34c04d2431cf6f888ae940f07

parent 79f59b0d

net/xfrm/xfrm_compat.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -5,6 +5,7 @@
		* Based on code and translator idea by: Florian Westphal <fw@strlen.de>
		*/
		#include <linux/compat.h>
		#include <linux/nospec.h>
		#include <linux/xfrm.h>
		#include <net/xfrm.h>

		@@ -435,6 +436,7 @@ static int xfrm_xlate32_attr(void dst, const struct nlattr nla,
		NL_SET_ERR_MSG(extack, "Bad attribute");
		return -EOPNOTSUPP;
		}
		type = array_index_nospec(type, XFRMA_MAX + 1);
		if (nla_len(nla) < compat_policy[type].len) {
		NL_SET_ERR_MSG(extack, "Attribute bad length");
		return -EOPNOTSUPP;