Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933789AbXKPUzS (ORCPT ); Fri, 16 Nov 2007 15:55:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755234AbXKPUzD (ORCPT ); Fri, 16 Nov 2007 15:55:03 -0500 Received: from mx1.redhat.com ([66.187.233.31]:55249 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755151AbXKPUzA (ORCPT ); Fri, 16 Nov 2007 15:55:00 -0500 Subject: [PATCH 2/3] mmap: round mmap hint address above mmap_min_addr 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 15:54:46 -0500 Message-Id: <1195246486.2924.87.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.3 (2.10.3-4.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2338 Lines: 71 If mmap_min_addr is set and a process attempts to mmap (not fixed) with a non-null hint address less than mmap_min_addr the mapping will fail the security checks. Since this is just a hint address this patch will round such a hint address above mmap_min_addr. gcj was found to try to be very frugal with vm usage and give hint addresses in the 8k-32k range. Without this patch all such programs failed and with the patch they happily get a higher address. This patch is wrappad in CONFIG_SECURITY since mmap_min_addr doesn't exist without it and there would be no security check possible no matter what. So we should not both compiling in this rounding if it is just a waste of time. Signed-off-by: Eric Paris --- mm/mmap.c | 10 ++++++++++ mm/nommu.c | 10 ++++++++++ 2 files changed, 20 insertions(+), 0 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 938313c..0c3ff74 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -912,6 +912,16 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, if (!len) return -EINVAL; +#ifdef CONFIG_SECURITY + /* + * If a hint addr is less than mmap_min_addr change addr to be as + * low as possible but still greater than mmap_min_addr + */ + if (!(flags & MAP_FIXED) && ((void *)addr != NULL) && + (addr < mmap_min_addr)) + addr = PAGE_ALIGN(mmap_min_addr); +#endif + error = arch_mmap_check(addr, len, flags); if (error) return error; diff --git a/mm/nommu.c b/mm/nommu.c index 35622c5..ea4d20a 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -829,6 +829,16 @@ unsigned long do_mmap_pgoff(struct file *file, void *result; int ret; +#ifdef CONFIG_SECURITY + /* + * If a hint addr is less than mmap_min_addr change addr to be as + * low as possible, but still greater than mmap_min_addr + */ + if (!(flags & MAP_FIXED) && ((void *)addr != NULL) && + (addr < mmap_min_addr)) + addr = PAGE_ALIGN(mmap_min_addr); +#endif + /* decide whether we should attempt the mapping, and if so what sort of * mapping */ ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/