summaryrefslogtreecommitdiff
path: root/kernel/bpf
diff options
context:
space:
mode:
authorRabin Vincent <rabin@rab.in>2016-01-12 20:17:08 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-31 11:29:01 -0800
commit35987ff2eaa05d70154c5bd28ebb2b70a7d8368b (patch)
tree65236be6744aaf9640ea327efb05c5cc5ded3cc6 /kernel/bpf
parentf7c1aee0b421663447aef58f58f103502bdc47e5 (diff)
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>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/verifier.c10
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 &&