From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754350AbcEJAT2 (ORCPT ); Mon, 9 May 2016 20:19:28 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57396 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754040AbcEJAFl (ORCPT ); Mon, 9 May 2016 20:05:41 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Kees Cook , Russell King , Catalin Marinas , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 06/54] arm64: standardize mmap_rnd() usage Date: Mon, 9 May 2016 17:04:25 -0700 Message-Id: <1462838713-31343-7-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1462838713-31343-1-git-send-email-kamal@canonical.com> References: <1462838713-31343-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt21 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Kees Cook commit dd04cff1dceab18226853b555cf07914648a235f upstream. In preparation for splitting out ET_DYN ASLR, this refactors the use of mmap_rnd() to be used similarly to arm and x86. This additionally enables mmap ASLR on legacy mmap layouts, which appeared to be missing on arm64, and was already supported on arm. Additionally removes a copy/pasted declaration of an unused function. Signed-off-by: Kees Cook Cc: Russell King Cc: Catalin Marinas Reviewed-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- arch/arm64/include/asm/elf.h | 1 - arch/arm64/mm/mmap.c | 18 +++++++++++------- 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 1f65be3..f724db0 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -125,7 +125,6 @@ typedef struct user_fpsimd_state elf_fpregset_t; * the loader. We need to make sure that it is out of the way of the program * that it will "exec", and that there is sufficient room for the brk. */ -extern unsigned long randomize_et_dyn(unsigned long base); #define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) /* diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 54922d1..ba776c0 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -49,15 +49,14 @@ static int mmap_is_legacy(void) static unsigned long mmap_rnd(void) { - unsigned long rnd = 0; + unsigned long rnd; - if (current->flags & PF_RANDOMIZE) - rnd = (long)get_random_int() & STACK_RND_MASK; + rnd = (unsigned long)get_random_int() & STACK_RND_MASK; return rnd << PAGE_SHIFT; } -static unsigned long mmap_base(void) +static unsigned long mmap_base(unsigned long rnd) { unsigned long gap = rlimit(RLIMIT_STACK); @@ -66,7 +65,7 @@ static unsigned long mmap_base(void) else if (gap > MAX_GAP) gap = MAX_GAP; - return PAGE_ALIGN(STACK_TOP - gap - mmap_rnd()); + return PAGE_ALIGN(STACK_TOP - gap - rnd); } /* @@ -75,15 +74,20 @@ static unsigned long mmap_base(void) */ void arch_pick_mmap_layout(struct mm_struct *mm) { + unsigned long random_factor = 0UL; + + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); + /* * Fall back to the standard layout if the personality bit is set, or * if the expected stack growth is unlimited: */ if (mmap_is_legacy()) { - mm->mmap_base = TASK_UNMAPPED_BASE; + mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; mm->get_unmapped_area = arch_get_unmapped_area; } else { - mm->mmap_base = mmap_base(); + mm->mmap_base = mmap_base(random_factor); mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } -- 2.7.4