From: Kees Cook <keescook@chromium.org>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
Palmer Dabbelt <palmer@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH v3 01/11] mm, fs: Move randomize_stack_top from fs to mm
Date: Thu, 18 Apr 2019 00:20:44 -0500 [thread overview]
Message-ID: <CAGXu5jKuOaGtb0S++_xpS=sxPLFwFqSgaecWae5iJ8f8eaQzDA@mail.gmail.com> (raw)
In-Reply-To: <20190417052247.17809-2-alex@ghiti.fr>
On Wed, Apr 17, 2019 at 12:24 AM Alexandre Ghiti <alex@ghiti.fr> wrote:
>
> This preparatory commit moves this function so that further introduction
> of generic topdown mmap layout is contained only in mm/util.c.
>
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/binfmt_elf.c | 20 --------------------
> include/linux/mm.h | 2 ++
> mm/util.c | 22 ++++++++++++++++++++++
> 3 files changed, 24 insertions(+), 20 deletions(-)
>
> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
> index 7d09d125f148..045f3b29d264 100644
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -662,26 +662,6 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
> * libraries. There is no binary dependent code anywhere else.
> */
>
> -#ifndef STACK_RND_MASK
> -#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */
> -#endif
> -
> -static unsigned long randomize_stack_top(unsigned long stack_top)
> -{
> - unsigned long random_variable = 0;
> -
> - if (current->flags & PF_RANDOMIZE) {
> - random_variable = get_random_long();
> - random_variable &= STACK_RND_MASK;
> - random_variable <<= PAGE_SHIFT;
> - }
> -#ifdef CONFIG_STACK_GROWSUP
> - return PAGE_ALIGN(stack_top) + random_variable;
> -#else
> - return PAGE_ALIGN(stack_top) - random_variable;
> -#endif
> -}
> -
> static int load_elf_binary(struct linux_binprm *bprm)
> {
> struct file *interpreter = NULL; /* to shut gcc up */
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 76769749b5a5..087824a5059f 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2312,6 +2312,8 @@ extern int install_special_mapping(struct mm_struct *mm,
> unsigned long addr, unsigned long len,
> unsigned long flags, struct page **pages);
>
> +unsigned long randomize_stack_top(unsigned long stack_top);
> +
> extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
>
> extern unsigned long mmap_region(struct file *file, unsigned long addr,
> diff --git a/mm/util.c b/mm/util.c
> index d559bde497a9..a54afb9b4faa 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -14,6 +14,8 @@
> #include <linux/hugetlb.h>
> #include <linux/vmalloc.h>
> #include <linux/userfaultfd_k.h>
> +#include <linux/elf.h>
> +#include <linux/random.h>
>
> #include <linux/uaccess.h>
>
> @@ -291,6 +293,26 @@ int vma_is_stack_for_current(struct vm_area_struct *vma)
> return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
> }
>
> +#ifndef STACK_RND_MASK
> +#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */
> +#endif
Oh right, here's the generic one... this should probably just copy
arm64's version instead. Then x86 can be tweaked (it uses
mmap_is_ia32() instead of is_compat_task() by default, but has a weird
override..)
Regardless, yes, this is a direct code move:
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
> +
> +unsigned long randomize_stack_top(unsigned long stack_top)
> +{
> + unsigned long random_variable = 0;
> +
> + if (current->flags & PF_RANDOMIZE) {
> + random_variable = get_random_long();
> + random_variable &= STACK_RND_MASK;
> + random_variable <<= PAGE_SHIFT;
> + }
> +#ifdef CONFIG_STACK_GROWSUP
> + return PAGE_ALIGN(stack_top) + random_variable;
> +#else
> + return PAGE_ALIGN(stack_top) - random_variable;
> +#endif
> +}
> +
> #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
> void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
> {
> --
> 2.20.1
>
--
Kees Cook
next prev parent reply other threads:[~2019-04-18 5:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 5:22 [PATCH v3 00/11] Provide generic top-down mmap layout functions Alexandre Ghiti
2019-04-17 5:22 ` [PATCH v3 01/11] mm, fs: Move randomize_stack_top from fs to mm Alexandre Ghiti
2019-04-18 5:20 ` Kees Cook [this message]
2019-04-17 5:22 ` [PATCH v3 02/11] arm64: Make use of is_compat_task instead of hardcoding this test Alexandre Ghiti
2019-04-18 4:32 ` Kees Cook
2019-04-18 5:23 ` Alex Ghiti
2019-04-22 19:53 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 03/11] arm64: Consider stack randomization for mmap base only when necessary Alexandre Ghiti
2019-04-18 4:37 ` Kees Cook
2019-04-18 5:24 ` Alex Ghiti
2019-04-22 19:53 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 04/11] arm64, mm: Move generic mmap layout functions to mm Alexandre Ghiti
2019-04-18 5:17 ` Kees Cook
2019-04-18 5:55 ` Alex Ghiti
2019-04-18 14:19 ` Kees Cook
2019-04-19 7:20 ` Alex Ghiti
2019-04-22 19:55 ` Christoph Hellwig
2019-04-28 14:27 ` Alex Ghiti
2019-04-22 19:54 ` Christoph Hellwig
2019-04-17 5:22 ` [PATCH v3 05/11] arm: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-04-18 5:26 ` Kees Cook
2019-04-18 6:01 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 06/11] arm: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-04-18 5:27 ` Kees Cook
2019-04-18 6:04 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 07/11] arm: Use generic mmap top-down layout Alexandre Ghiti
2019-04-18 5:28 ` Kees Cook
2019-04-18 6:06 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-04-18 5:30 ` Kees Cook
2019-04-18 6:06 ` Alex Ghiti
2019-04-18 21:27 ` Paul Burton
2019-04-19 7:20 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 09/11] mips: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:08 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 10/11] mips: Use generic mmap top-down layout Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:08 ` Alex Ghiti
2019-04-17 5:22 ` [PATCH v3 11/11] riscv: Make mmap allocation top-down by default Alexandre Ghiti
2019-04-18 5:31 ` Kees Cook
2019-04-18 6:09 ` Alex Ghiti
2019-04-22 19:56 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAGXu5jKuOaGtb0S++_xpS=sxPLFwFqSgaecWae5iJ8f8eaQzDA@mail.gmail.com' \
--to=keescook@chromium.org \
--cc=akpm@linux-foundation.org \
--cc=alex@ghiti.fr \
--cc=aou@eecs.berkeley.edu \
--cc=catalin.marinas@arm.com \
--cc=hch@lst.de \
--cc=jhogan@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux@armlinux.org.uk \
--cc=mcgrof@kernel.org \
--cc=palmer@sifive.com \
--cc=paul.burton@mips.com \
--cc=ralf@linux-mips.org \
--cc=viro@zeniv.linux.org.uk \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).