Daniel Borkmann b569c1c622 net: bpf: arm64: address randomize and write protect JIT code ... This is the ARM64 variant for 314beb9bca ("x86: bpf_jit_comp: secure bpf jit against spraying attacks"). Thanks to commit 11d91a770f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support") which added necessary infrastructure, we can now implement RO marking of eBPF generated JIT image pages and randomize start offset for the JIT code, so that it does not reside directly on a page boundary anymore. Likewise, the holes are filled with illegal instructions: here we use BRK #0x100 (opcode 0xd4202000) to trigger a fault in the kernel (unallocated BRKs would trigger a fault through do_debug_exception). This seems more reliable as we don't have a guaranteed undefined instruction space on ARM64. This is basically the ARM64 variant of what we already have in ARM via commit 55309dd3d4 ("net: bpf: arm: address randomize and write protect JIT code"). Moreover, this commit also presents a merge resolution due to conflicts with commit 60a3b2253c ("net: bpf: make eBPF interpreter images read-only") as we don't use kfree() in bpf_jit_free() anymore to release the locked bpf_prog structure, but instead bpf_prog_unlock_free() through a different allocator. JIT tested on aarch64 with BPF test suite. Reference: http://mainisusuallyafunction.blogspot.com/2012/11/attacking-hardened-linux-systems-with.html Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Reviewed-by: Zi Shen Lim <zlim.lnx@gmail.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>		2014-10-20 17:47:03 +01:00
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bpf_jit.h	arm64: eBPF JIT compiler	2014-09-08 14:39:21 +01:00
bpf_jit_comp.c	net: bpf: arm64: address randomize and write protect JIT code	2014-10-20 17:47:03 +01:00
Makefile	arm64: eBPF JIT compiler	2014-09-08 14:39:21 +01:00