From 2bb0627a9730d7ff6f3c7c7d09e5318b00d2edf1 Mon Sep 17 00:00:00 2001
From: Joe Lawrence <joe.lawrence@redhat.com>
Date: Mon, 11 May 2020 16:59:29 -0400
Subject: [PATCH v2] netlabel: cope with NULL catmap

Kernels:
4.18.0-193.el8

Changes since last build:
arches: x86_64 ppc64le

---------------------------

Modifications:
- For minimal kpatch fix, update netlbl_catmap_getlong() to avoid NULL
  pointetr dereference (suggested by Paolo).
- Add kpatch-build avoidance for ppc64le leaf functions (mcount calls
  not replaced by nops).

(embargoed patch from rhkernel-team-list)
Author: Paolo Abeni <pabeni@redhat.com>
Date:   Wed May 6 16:36:19 2020 +0200

    netlabel: cope with NULL catmap

    Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1827251
    Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=28403086
    Tested: vs bz repro
    CVE: CVE-2020-10711
    Upstream status: RHEL-only

    The cipso and calipso code can set the MLS_CAT attribute on
    successful parsing, even if the corresponding catmap has
    not be allocated, as per current configuration and external
    input.

    Later, selinux code tries tp access the catmap if the MLS_CAT flag
    is present via netlbl_catmap_getlong(). That may cause null ptr
    dereference while processing incoming network traffic.

    Address the issue setting the MLS_CAT flag only if the catmap is
    really allocated. Additionally let netlbl_catmap_getlong() cope
    with NULL catmap

    Fixes: 4b8feff251da ("netlabel: fix the horribly broken catmap functions")
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
---

Accompanying the kpatch will be a change to update kpatch.spec with a
v2-patch filename and .gitignore / sources updates to reflect the new
patch name.

 net/netlabel/netlabel_kapi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index ee3e5b6471a6..93807c049a5b 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -748,6 +748,14 @@ int netlbl_catmap_getlong(struct netlbl_lsm_catmap *catmap,
 	if ((off & (BITS_PER_LONG - 1)) != 0)
 		return -EINVAL;
 
+	/* a null catmap is equivalent to an empty one */
+	if (!catmap) {
+		if (jiffies == 0)
+			pr_debug("workaround for kpatch ppc64le leaf function\n");
+		*offset = (u32)-1;
+		return 0;
+	}
+
 	if (off < catmap->startbit) {
 		off = catmap->startbit;
 		*offset = off;
-- 
2.21.3