From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rik van Riel , Michel Lespinasse , Oleg Nesterov , Ingo Molnar , Adrian Sendroiu , Andrew Morton , Linus Torvalds Subject: [ 05/45] x86 get_unmapped_area(): use proper mmap base for bottom-up direction Date: Sun, 18 Aug 2013 13:35:54 -0700 Message-Id: <20130818203621.368077110@linuxfoundation.org> In-Reply-To: <20130818203620.996166594@linuxfoundation.org> References: <20130818203620.996166594@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Radu Caragea commit df54d6fa54275ce59660453e29d1228c2b45a826 upstream. When the stack is set to unlimited, the bottomup direction is used for mmap-ings but the mmap_base is not used and thus effectively renders ASLR for mmapings along with PIE useless. Reviewed-by: Rik van Riel Cc: Michel Lespinasse Cc: Oleg Nesterov Acked-by: Ingo Molnar Cc: Adrian Sendroiu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/sys_x86_64.c | 2 +- arch/x86/mm/mmap.c | 2 +- include/linux/sched.h | 1 + 3 files changed, 3 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -101,7 +101,7 @@ static void find_start_end(unsigned long *begin = new_begin; } } else { - *begin = TASK_UNMAPPED_BASE; + *begin = mmap_legacy_base(); *end = TASK_SIZE; } } --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -98,7 +98,7 @@ static unsigned long mmap_base(void) * Bottom-up (legacy) layout on X86_32 did not support randomization, X86_64 * does, but not when emulating X86_32 */ -static unsigned long mmap_legacy_base(void) +unsigned long mmap_legacy_base(void) { if (mmap_is_ia32()) return TASK_UNMAPPED_BASE; --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -314,6 +314,7 @@ struct nsproxy; struct user_namespace; #ifdef CONFIG_MMU +extern unsigned long mmap_legacy_base(void); extern void arch_pick_mmap_layout(struct mm_struct *mm); extern unsigned long arch_get_unmapped_area(struct file *, unsigned long, unsigned long,