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authorAlexei Starovoitov <ast@fb.com>2016-09-01 18:37:21 -0700
committerDavid S. Miller <davem@davemloft.net>2016-09-02 10:46:44 -0700
commitea2e7ce5d0fc878463ba39deb46cf2ab20398fd2 (patch)
tree7b67c9e451afca1b570835bbd75d9be7aebc931e
parent569e937e0100c8841619bd2150d15682141a6b0b (diff)
bpf: support 8-byte metafield access
The verifier supported only 4-byte metafields in struct __sk_buff and struct xdp_md. The metafields in upcoming struct bpf_perf_event are 8-byte to match register width in struct pt_regs. Teach verifier to recognize 8-byte metafield access. The patch doesn't affect safety of sockets and xdp programs. They check for 4-byte only ctx access before these conditions are hit. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--kernel/bpf/verifier.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abb61f3f6900..c1c9e441f0f5 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2333,7 +2333,8 @@ static int do_check(struct verifier_env *env)
if (err)
return err;
- if (BPF_SIZE(insn->code) != BPF_W) {
+ if (BPF_SIZE(insn->code) != BPF_W &&
+ BPF_SIZE(insn->code) != BPF_DW) {
insn_idx++;
continue;
}
@@ -2642,9 +2643,11 @@ static int convert_ctx_accesses(struct verifier_env *env)
for (i = 0; i < insn_cnt; i++, insn++) {
u32 insn_delta, cnt;
- if (insn->code == (BPF_LDX | BPF_MEM | BPF_W))
+ if (insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
+ insn->code == (BPF_LDX | BPF_MEM | BPF_DW))
type = BPF_READ;
- else if (insn->code == (BPF_STX | BPF_MEM | BPF_W))
+ else if (insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
+ insn->code == (BPF_STX | BPF_MEM | BPF_DW))
type = BPF_WRITE;
else
continue;