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[3/6] xfrm/compat: prevent potential spectre v1 gadget in xfrm_xlate32_attr()

Message ID 20230208114322.266510-4-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit b6ee896385380aa621102e8ea402ba12db1cabff
Delegated to: Netdev Maintainers
Headers show
Series [1/6] Fix XFRM-I support for nested ESP tunnels | expand

Checks

Context Check Description
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Pull request is its own cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers fail 1 blamed authors not CCed: 0x7f454c46@gmail.com; 3 maintainers not CCed: 0x7f454c46@gmail.com edumazet@google.com pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 14 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Steffen Klassert Feb. 8, 2023, 11:43 a.m. UTC 
From: Eric Dumazet <edumazet@google.com>

  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.

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>
---
 net/xfrm/xfrm_compat.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c
index 12405aa5bce8..8cbf45a8bcdc 100644
--- a/net/xfrm/xfrm_compat.c
+++ b/net/xfrm/xfrm_compat.c
@@ -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>
 
@@ -437,6 +438,7 @@  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;