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Message-Id: <20190730055113.23635-2-alex@ghiti.fr>
Date: Tue, 30 Jul 2019 01:51:00 -0400
From: Alexandre Ghiti <alex@...ti.fr>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Luis Chamberlain <mcgrof@...nel.org>,
Christoph Hellwig <hch@....de>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Ralf Baechle <ralf@...ux-mips.org>,
Paul Burton <paul.burton@...s.com>,
James Hogan <jhogan@...nel.org>,
Palmer Dabbelt <palmer@...ive.com>,
Albert Ou <aou@...s.berkeley.edu>,
Alexander Viro <viro@...iv.linux.org.uk>,
Kees Cook <keescook@...omium.org>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-mips@...r.kernel.org, linux-riscv@...ts.infradead.org,
linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
Alexandre Ghiti <alex@...ti.fr>
Subject: [PATCH v5 01/14] mm, fs: Move randomize_stack_top from fs to mm
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@...ti.fr>
Acked-by: Kees Cook <keescook@...omium.org>
Reviewed-by: Christoph Hellwig <hch@....de>
Reviewed-by: Luis Chamberlain <mcgrof@...nel.org>
---
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 d4e11b2e04f6..cec3b4146440 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -670,26 +670,6 @@ 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 0334ca97c584..ae0e5d241eb8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2351,6 +2351,8 @@ 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 e6351a80f248..15a4fb0f5473 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -16,6 +16,8 @@
#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>
@@ -293,6 +295,26 @@ 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
+
+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
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