diff options
| author | Rabin Vincent <rabin@rab.in> | 2016-01-12 20:17:08 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-01-12 17:06:53 -0500 |
| commit | 229394e8e62a4191d592842cf67e80c62a492937 (patch) | |
| tree | b16b3b389afb1bb660373bab3ec2f986d99a6e13 /kernel | |
| parent | 7aaed57c5c2890634cfadf725173c7c68ea4cb4f (diff) | |
| download | linux-229394e8e62a4191d592842cf67e80c62a492937.tar.bz2 | |
net: bpf: reject invalid shifts
On ARM64, a BUG() is triggered in the eBPF JIT if a filter with a
constant shift that can't be encoded in the immediate field of the
UBFM/SBFM instructions is passed to the JIT. Since these shifts
amounts, which are negative or >= regsize, are invalid, reject them in
the eBPF verifier and the classic BPF filter checker, for all
architectures.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a7945d10b378..d1d3e8f57de9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1121,6 +1121,16 @@ static int check_alu_op(struct verifier_env *env, struct bpf_insn *insn) return -EINVAL; } + if ((opcode == BPF_LSH || opcode == BPF_RSH || + opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { + int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; + + if (insn->imm < 0 || insn->imm >= size) { + verbose("invalid shift %d\n", insn->imm); + return -EINVAL; + } + } + /* pattern match 'bpf_add Rx, imm' instruction */ if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 && regs[insn->dst_reg].type == FRAME_PTR && |