[RFCv2 05/16] bpf: recognize 64bit immediate loads as consts
From: Jakub Kicinski <hidden>
Date: 2016-08-26 18:16:05
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
When verifier sees a generic BPF_LD | BPF_IMM | BPF_DW it should mark the dst register as CONST_IMM with the loaded value stored in imm. Signed-off-by: Jakub Kicinski <redacted> --- kernel/bpf/verifier.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abb61f3f6900..db68a0e5db1e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c@@ -1787,9 +1787,14 @@ static int check_ld_imm(struct verifier_env *env, struct bpf_insn *insn) if (err) return err; - if (insn->src_reg == 0) + if (insn->src_reg == 0) { /* generic move 64-bit immediate into a register */ + u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; + + regs[insn->dst_reg].type = CONST_IMM; + regs[insn->dst_reg].imm = imm; return 0; + } /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */ BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
--
1.9.1