include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Acked-by: Antony Antony <antony.antony@secunet.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index b96c1ea7166d6d277e50dc476f0927a16651a0c8..26f456b1f33e562512d09aeb9e26be2a31a35633 100644 (file)
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h
@@ -213,13 +213,13 @@ enum {
        XFRM_MSG_GETSPDINFO,
 #define XFRM_MSG_GETSPDINFO XFRM_MSG_GETSPDINFO
 
+       XFRM_MSG_MAPPING,
+#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
+
        XFRM_MSG_SETDEFAULT,
 #define XFRM_MSG_SETDEFAULT XFRM_MSG_SETDEFAULT
        XFRM_MSG_GETDEFAULT,
 #define XFRM_MSG_GETDEFAULT XFRM_MSG_GETDEFAULT
-
-       XFRM_MSG_MAPPING,
-#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
        __XFRM_MSG_MAX
 };
 #define XFRM_MSG_MAX (__XFRM_MSG_MAX - 1)

diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index d59276f48d4fc12a46b93c535c014336695fb6e3..94ea2a8b2bb7366b0ab153ca21cc225ee655a78c 100644 (file)
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c
@@ -126,6 +126,8 @@ static const struct nlmsg_perm nlmsg_xfrm_perms[] =
        { XFRM_MSG_NEWSPDINFO,  NETLINK_XFRM_SOCKET__NLMSG_WRITE },
        { XFRM_MSG_GETSPDINFO,  NETLINK_XFRM_SOCKET__NLMSG_READ  },
        { XFRM_MSG_MAPPING,     NETLINK_XFRM_SOCKET__NLMSG_READ  },
+       { XFRM_MSG_SETDEFAULT,  NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+       { XFRM_MSG_GETDEFAULT,  NETLINK_XFRM_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_audit_perms[] =
@@ -189,7 +191,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
                 * structures at the top of this file with the new mappings
                 * before updating the BUILD_BUG_ON() macro!
                 */
-               BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MAPPING);
+               BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_GETDEFAULT);
                err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
                                 sizeof(nlmsg_xfrm_perms));
                break;