Messages in this thread | | | Date | Thu, 25 Jun 2015 06:34:12 -0700 | From | Alexei Starovoitov <> | Subject | Re: [PATCH] arm64: bpf: fix out-of-bounds read in bpf2a64_offset() |
| |
On 6/25/15 5:47 AM, Xi Wang wrote: > Problems occur when bpf_to or bpf_from has value prog->len - 1 (e.g., > "Very long jump backwards" in test_bpf where the last instruction is a > jump): since ctx->offset has length prog->len, ctx->offset[bpf_to + 1] > or ctx->offset[bpf_from + 1] will cause an out-of-bounds read, leading > to a bogus jump offset and kernel panic. > > This patch moves updating ctx->offset to after calling build_insn(), > and changes indexing to use bpf_to and bpf_from without + 1. > > Cc: Zi Shen Lim<zlim.lnx@gmail.com> > Cc: Alexei Starovoitov<ast@plumgrid.com> > Cc: Will Deacon<will.deacon@arm.com> > Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler") > Signed-off-by: Xi Wang<xi.wang@gmail.com>
Nice catch! Looks good to me. Acked-by: Alexei Starovoitov <ast@plumgrid.com>
| |