From 3324603524925c7727207027d1c15e597412d15e Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Thu, 9 Jul 2015 14:20:36 -0400 Subject: [PATCH] selinux: don't waste ebitmap space when importing NetLabel categories At present we don't create efficient ebitmaps when importing NetLabel category bitmaps. This can present a problem when comparing ebitmaps since ebitmap_cmp() is very strict about these things and considers these wasteful ebitmaps not equal when compared to their more efficient counterparts, even if their values are the same. This isn't likely to cause problems on 64-bit systems due to a bit of luck on how NetLabel/CIPSO works and the default ebitmap size, but it can be a problem on 32-bit systems. This patch fixes this problem by being a bit more intelligent when importing NetLabel category bitmaps by skipping over empty sections which should result in a nice, efficient ebitmap. Cc: stable@vger.kernel.org # 3.17 Signed-off-by: Paul Moore --- security/selinux/ss/ebitmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c index afe6a269ec17..57644b1dc42e 100644 --- a/security/selinux/ss/ebitmap.c +++ b/security/selinux/ss/ebitmap.c @@ -153,6 +153,12 @@ int ebitmap_netlbl_import(struct ebitmap *ebmap, if (offset == (u32)-1) return 0; + /* don't waste ebitmap space if the netlabel bitmap is empty */ + if (bitmap == 0) { + offset += EBITMAP_UNIT_SIZE; + continue; + } + if (e_iter == NULL || offset >= e_iter->startbit + EBITMAP_SIZE) { e_prev = e_iter;