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bpf: recognize 64bit immediate loads as consts
When running as parser interpret BPF_LD | BPF_IMM | BPF_DW instructions as loading CONST_IMM with the value stored in imm. The verifier will continue not recognizing those due to concerns about search space/program complexity increase. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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1 changed files with 12 additions and 2 deletions
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@ -1769,9 +1769,19 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
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if (err)
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return err;
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if (insn->src_reg == 0)
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/* generic move 64-bit immediate into a register */
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if (insn->src_reg == 0) {
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/* generic move 64-bit immediate into a register,
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* only analyzer needs to collect the ld_imm value.
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*/
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u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
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if (!env->analyzer_ops)
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return 0;
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regs[insn->dst_reg].type = CONST_IMM;
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regs[insn->dst_reg].imm = imm;
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return 0;
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}
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/* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
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BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
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