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authorJason Cooper <jason@lakedaemon.net>2016-10-11 13:53:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-11 15:06:32 -0700
commit9c6f0902a55226b08b9703408f04b258b9afa0bc (patch)
tree49d7c8d8f3e1e058c7436b2d21d0430623bca186 /arch
parent99fdafdeacfa99ca9047641b684fa2aaf094a661 (diff)
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.net Signed-off-by: Jason Cooper <jason@lakedaemon.net> Acked-by: Kees 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/process.c3
-rw-r--r--arch/x86/kernel/sys_x86_64.c5
2 files changed, 2 insertions, 6 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 28cea7802ecb..0888a879120f 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -509,8 +509,7 @@ unsigned long arch_align_stack(unsigned long sp)
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
- unsigned long range_end = mm->brk + 0x02000000;
- return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+ return randomize_page(mm->brk, 0x02000000);
}
/*
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 10e0272d789a..a55ed63b9f91 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -101,7 +101,6 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
unsigned long *end)
{
if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
- unsigned long new_begin;
/* This is usually used needed to map code in small
model, so it needs to be in the first 31bit. Limit
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,
*begin = 0x40000000;
*end = 0x80000000;
if (current->flags & PF_RANDOMIZE) {
- new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
- if (new_begin)
- *begin = new_begin;
+ *begin = randomize_page(*begin, 0x02000000);
}
} else {
*begin = current->mm->mmap_legacy_base;