From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com From: Jason Cooper Date: Wed, 3 Aug 2016 23:39:10 +0000 Message-Id: <20160803233913.32511-5-jason@lakedaemon.net> In-Reply-To: <20160803233913.32511-1-jason@lakedaemon.net> References: <20160728204730.27453-1-jason@lakedaemon.net> <20160803233913.32511-1-jason@lakedaemon.net> Subject: [kernel-hardening] [PATCH v3 4/7] arm64: Use simpler API for random address requests To: Kees Cook , Michael Ellerman , "Roberts, William C" , Yann Droneaud Cc: Linux-MM , LKML , kernel-hardening , Russell King - ARM Linux , Andrew Morton , Theodore Ts'o , Arnd Bergmann , gregkh@linuxfoundation.org, Catalin Marinas , Will Deacon , Ralf Baechle , benh@kernel.crashing.org, paulus@samba.org, "David S. Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , x86@kernel.org, viro@zeniv.linux.org.uk, Nick Kralevich , Jeffrey Vander Stoep , Daniel Cashman , Jason Cooper List-ID: 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. Signed-off-by: Jason Cooper Acked-by: Will Deacon --- Changes from v2: - s/randomize_addr/randomize_page/ (Kees Cook) arch/arm64/kernel/process.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 6cd2612236dc..6ac2950ffb78 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -374,12 +374,8 @@ unsigned long arch_align_stack(unsigned long sp) unsigned long arch_randomize_brk(struct mm_struct *mm) { - unsigned long range_end = mm->brk; - if (is_compat_task()) - range_end += 0x02000000; + return randomize_page(mm->brk, 0x02000000); else - range_end += 0x40000000; - - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; + return randomize_page(mm->brk, 0x40000000); } -- 2.9.2