From: William Roberts <william.c.roberts@intel.com>
Date: Tue, 23 Aug 2016 20:49:23 +0000 (-0700)
Subject: selinux: detect invalid ebitmap
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=74d977b65e45bc9b536b429e7f3b5e3a8e459026;p=linux-beck.git

selinux: detect invalid ebitmap

When count is 0 and the highbit is not zero, the ebitmap is not
valid and the internal node is not allocated. This causes issues
when routines, like mls_context_isvalid() attempt to use the
ebitmap_for_each_bit() and ebitmap_node_get_bit() as they assume
a highbit > 0 will have a node allocated.

Signed-off-by: William Roberts <william.c.roberts@intel.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
---

diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c
index 894b6cdc11c5..7d10e5d418bb 100644
--- a/security/selinux/ss/ebitmap.c
+++ b/security/selinux/ss/ebitmap.c
@@ -374,6 +374,9 @@ int ebitmap_read(struct ebitmap *e, void *fp)
 		goto ok;
 	}
 
+	if (e->highbit && !count)
+		goto bad;
+
 	for (i = 0; i < count; i++) {
 		rc = next_entry(&startbit, fp, sizeof(u32));
 		if (rc < 0) {