From 20182390c4134478d795a096ddb8dddcc648e28a Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 4 Mar 2019 21:08:53 +0100 Subject: bpf: fix replace_map_fd_with_map_ptr's ldimm64 second imm field Non-zero imm value in the second part of the ldimm64 instruction for BPF_PSEUDO_MAP_FD is invalid, and thus must be rejected. The map fd only ever sits in the first instructions' imm field. None of the BPF loaders known to us are using it, so risk of regression is minimal. For clarity and consistency, the few insn->{src_reg,imm} occurrences are rewritten into insn[0].{src_reg,imm}. Add a test case to the BPF selftest suite as well. Fixes: 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn") Signed-off-by: Daniel Borkmann Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a7b96bf0e654..ce166a002d16 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6678,17 +6678,17 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) /* valid generic load 64-bit imm */ goto next_insn; - if (insn->src_reg != BPF_PSEUDO_MAP_FD) { - verbose(env, - "unrecognized bpf_ld_imm64 insn\n"); + if (insn[0].src_reg != BPF_PSEUDO_MAP_FD || + insn[1].imm != 0) { + verbose(env, "unrecognized bpf_ld_imm64 insn\n"); return -EINVAL; } - f = fdget(insn->imm); + f = fdget(insn[0].imm); map = __bpf_map_get(f); if (IS_ERR(map)) { verbose(env, "fd %d is not pointing to valid bpf_map\n", - insn->imm); + insn[0].imm); return PTR_ERR(map); } -- cgit