From 4d31f30148cea6e97e42616231eed55295117fe7 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 1 Nov 2018 00:05:53 +0100 Subject: [PATCH] bpf: don't set id on after map lookup with ptr_to_map_val return In the verifier there is no such semantics where registers with PTR_TO_MAP_VALUE type have an id assigned to them. This is only used in PTR_TO_MAP_VALUE_OR_NULL and later on nullified once the test against NULL has been pattern matched and type transformed into PTR_TO_MAP_VALUE. Fixes: 3e6a4b3e0289 ("bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE") Signed-off-by: Daniel Borkmann Cc: Roman Gushchin Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 774fa40a32ae..1971ca325fb4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2852,10 +2852,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn regs[BPF_REG_0].type = NOT_INIT; } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL || fn->ret_type == RET_PTR_TO_MAP_VALUE) { - if (fn->ret_type == RET_PTR_TO_MAP_VALUE) - regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; - else - regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; /* There is no offset yet applied, variable or fixed */ mark_reg_known_zero(env, regs, BPF_REG_0); /* remember map_ptr, so that check_map_access() @@ -2868,7 +2864,12 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn return -EINVAL; } regs[BPF_REG_0].map_ptr = meta.map_ptr; - regs[BPF_REG_0].id = ++env->id_gen; + if (fn->ret_type == RET_PTR_TO_MAP_VALUE) { + regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; + } else { + regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; + regs[BPF_REG_0].id = ++env->id_gen; + } } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) { int id = acquire_reference_state(env, insn_idx); if (id < 0) -- 2.30.2