diff options
| author | Rabin Vincent <rabin@rab.in> | 2016-01-12 22:17:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-31 22:25:51 +0300 |
| commit | f2da6274a5f9d858a6a81f1f11966f42e476f1f3 (patch) | |
| tree | ce588f7569f6328ad5086f33cdfaad47c7d9b22c | |
| parent | 89583f678088043220fe50fc88fc405ba2d27726 (diff) | |
| download | linux-f2da6274a5f9d858a6a81f1f11966f42e476f1f3.tar.xz | |
net: bpf: reject invalid shifts
[ Upstream commit 229394e8e62a4191d592842cf67e80c62a492937 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/bpf/verifier.c | 10 | ||||
| -rw-r--r-- | net/core/filter.c | 5 |
2 files changed, 15 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b074b23000d6..36c6efeffdd5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1058,6 +1058,16 @@ static int check_alu_op(struct reg_state *regs, 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 && diff --git a/net/core/filter.c b/net/core/filter.c index bb18c3680001..49b44879dc7f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -781,6 +781,11 @@ static int bpf_check_classic(const struct sock_filter *filter, if (ftest->k == 0) return -EINVAL; break; + case BPF_ALU | BPF_LSH | BPF_K: + case BPF_ALU | BPF_RSH | BPF_K: + if (ftest->k >= 32) + return -EINVAL; + break; case BPF_LD | BPF_MEM: case BPF_LDX | BPF_MEM: case BPF_ST: |