From 0142c56682fbf969cc08b1e3f9223384ede29a5f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Fri, 15 Mar 2024 18:28:44 +0100 Subject: [PATCH] selinux: reject invalid ebitmaps MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reject ebitmaps with a node containing an empty map or with an incorrect highbit. Both checks are already performed by userspace, the former since 2008 (patch 13cd4c896068 ("initial import from svn trunk revision 2950")), the latter since v2.7 in 2017 (patch 75b14a5de10a ("libsepol: ebitmap: reject loading bitmaps with incorrect high bit")). Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore --- security/selinux/ss/ebitmap.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c index 67c1a73cd5ee..f1ba333f127d 100644 --- a/security/selinux/ss/ebitmap.c +++ b/security/selinux/ss/ebitmap.c @@ -448,6 +448,10 @@ int ebitmap_read(struct ebitmap *e, void *fp) goto bad; } map = le64_to_cpu(mapbits); + if (!map) { + pr_err("SELinux: ebitmap: empty map\n"); + goto bad; + } index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE; while (map) { @@ -455,6 +459,13 @@ int ebitmap_read(struct ebitmap *e, void *fp) map = EBITMAP_SHIFT_UNIT_SIZE(map); } } + + if (n && n->startbit + EBITMAP_SIZE != e->highbit) { + pr_err("SELinux: ebitmap: high bit %d is not equal to the expected value %ld\n", + e->highbit, n->startbit + EBITMAP_SIZE); + goto bad; + } + ok: rc = 0; out: