From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com From: Jason Cooper Date: Sat, 30 Jul 2016 15:42:41 +0000 Message-Id: <20160730154244.403-5-jason@lakedaemon.net> In-Reply-To: <20160730154244.403-1-jason@lakedaemon.net> References: <20160728204730.27453-1-jason@lakedaemon.net> <20160730154244.403-1-jason@lakedaemon.net> Subject: [kernel-hardening] [PATCH v2 4/7] arm64: Use simpler API for random address requests To: william.c.roberts@intel.com, Yann Droneaud , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, tytso@mit.edu, arnd@arndb.de, gregkh@linuxfoundation.org, catalin.marinas@arm.com, will.deacon@arm.com, ralf@linux-mips.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk, nnk@google.com, jeffv@google.com, dcashman@android.com, 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 v1: - Add Ack for arm64 (Will Deacon) 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..11bf454baf86 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_addr(mm->brk, 0x02000000); else - range_end += 0x40000000; - - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; + return randomize_addr(mm->brk, 0x40000000); } -- 2.9.2