On Mon, Mar 02, 2015 at 04:19:43PM -0800, Kees Cook wrote: > To address the "offset2lib" ASLR weakness[1], this separates ET_DYN > ASLR from mmap ASLR, as already done on s390. The architectures > that are already randomizing mmap (arm, arm64, mips, powerpc, s390, > and x86), have their various forms of arch_mmap_rnd() made available > via the new CONFIG_ARCH_HAS_ELF_RANDOMIZE. For these architectures, > arch_randomize_brk() is collapsed as well. > > This is an alternative to the solutions in: > https://lkml.org/lkml/2015/2/23/442 I've run this on one of my ARM platforms, and it looks fine. 2a05e000-2a05f000 r-xp 00000000 00:10 7750376 /root/offset2lib/get_offset2lib 2a066000-2a067000 r--p 00000000 00:10 7750376 /root/offset2lib/get_offset2lib 2a067000-2a068000 rw-p 00001000 00:10 7750376 /root/offset2lib/get_offset2lib b6dfd000-b6ed3000 r-xp 00000000 00:10 1376508 /lib/arm-linux-gnueabihf/libc-2.15.so b6ed3000-b6eda000 ---p 000d6000 00:10 1376508 /lib/arm-linux-gnueabihf/libc-2.15.so b6eda000-b6edc000 r--p 000d5000 00:10 1376508 /lib/arm-linux-gnueabihf/libc-2.15.so b6edc000-b6edd000 rw-p 000d7000 00:10 1376508 /lib/arm-linux-gnueabihf/libc-2.15.so b6edd000-b6ee0000 rw-p 00000000 00:00 0 b6ef9000-b6f10000 r-xp 00000000 00:10 1376509 /lib/arm-linux-gnueabihf/ld-2.15.so b6f13000-b6f17000 rw-p 00000000 00:00 0 b6f17000-b6f18000 r--p 00016000 00:10 1376509 /lib/arm-linux-gnueabihf/ld-2.15.so b6f18000-b6f19000 rw-p 00017000 00:10 1376509 /lib/arm-linux-gnueabihf/ld-2.15.so bea3b000-bea5c000 rw-p 00000000 00:00 0 [stack] bec22000-bec23000 r-xp 00000000 00:00 0 [sigpage] ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors] And offset2lib shows a random offset: Offset2lib (libc): 0xffffffff73261000 Offset2lib (libc): 0xffffffff732ce000 Offset2lib (libc): 0xffffffff731b1000 Offset2lib (libc): 0xffffffff73252000 So, for ARM: Tested-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Thanks. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.
