Commit 9c6f0902 authored by Jason Cooper's avatar Jason Cooper Committed by Linus Torvalds

x86: use simpler API for random address requests

Currently, all callers to randomize_range() set the length to 0 and
calculate end by adding a constant to the start address.  We can simplify
the API to remove a bunch of needless checks and variables.

Use the new randomize_addr(start, range) call to set the requested
address.

Link: http://lkml.kernel.org/r/20160803233913.32511-3-jason@lakedaemon.netSigned-off-by: default avatarJason Cooper <jason@lakedaemon.net>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 99fdafde
...@@ -509,8 +509,7 @@ unsigned long arch_align_stack(unsigned long sp) ...@@ -509,8 +509,7 @@ unsigned long arch_align_stack(unsigned long sp)
unsigned long arch_randomize_brk(struct mm_struct *mm) unsigned long arch_randomize_brk(struct mm_struct *mm)
{ {
unsigned long range_end = mm->brk + 0x02000000; return randomize_page(mm->brk, 0x02000000);
return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
} }
/* /*
......
...@@ -101,7 +101,6 @@ static void find_start_end(unsigned long flags, unsigned long *begin, ...@@ -101,7 +101,6 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
unsigned long *end) unsigned long *end)
{ {
if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) { if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
unsigned long new_begin;
/* This is usually used needed to map code in small /* This is usually used needed to map code in small
model, so it needs to be in the first 31bit. Limit model, so it needs to be in the first 31bit. Limit
it to that. This means we need to move the it to that. This means we need to move the
...@@ -112,9 +111,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin, ...@@ -112,9 +111,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
*begin = 0x40000000; *begin = 0x40000000;
*end = 0x80000000; *end = 0x80000000;
if (current->flags & PF_RANDOMIZE) { if (current->flags & PF_RANDOMIZE) {
new_begin = randomize_range(*begin, *begin + 0x02000000, 0); *begin = randomize_page(*begin, 0x02000000);
if (new_begin)
*begin = new_begin;
} }
} else { } else {
*begin = current->mm->mmap_legacy_base; *begin = current->mm->mmap_legacy_base;
......
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