Subject: [PATCH 3/3] security: allow capable check to permit mmap or low vm space From: Eric Paris To: linux-kernel@vger.kernel.org Cc: jmorris@namei.org, sds@tycho.nsa.gov, selinux@tycho.nsa.gov, alan@redhat.com, chrisw@redhat.com, hpa@zytor.com, akpm@linux-foundation.org Content-Type: text/plain Date: Fri, 16 Nov 2007 15:55:45 -0500 Message-Id: <1195246545.2924.88.camel@localhost.localdomain> Mime-Version: 1.0 Sender: owner-selinux@tycho.nsa.gov List-Id: selinux@tycho.nsa.gov On a kernel with CONFIG_SECURITY but without an LSM which implements security_file_mmap it is impossible for an application to mmap addresses lower than mmap_min_addr. Based on a suggestion from a developer in the openwall community this patch adds a check for CAP_SYS_RAWIO. It is assumed that any process with this capability can harm the system a lot more easily than writing some stuff on the zero page and then trying to get the kernel to trip over itself. It also means that programs like X on i686 which use vm86 emulation can work even with mmap_min_addr set. Signed-off-by: Eric Paris --- security/dummy.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/security/dummy.c b/security/dummy.c index 6d895ad..3ccfbbe 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -426,7 +426,7 @@ static int dummy_file_mmap (struct file *file, unsigned long reqprot, unsigned long addr, unsigned long addr_only) { - if (addr < mmap_min_addr) + if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO)) return -EACCES; return 0; } -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@tycho.nsa.gov with the words "unsubscribe selinux" without quotes as the message.