diff options
| author | Lorenz Bauer <lmb@cloudflare.com> | 2020-09-21 13:12:21 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-21 15:00:40 -0700 |
| commit | d7b9454a4f6333bf145189b8e769011d15bdd50e (patch) | |
| tree | 6de8d615d0a0658a7d2c418f3bbccde7103cce33 /kernel | |
| parent | 9436ef6e862b9ca22e5b12f87b106e07d5af4cae (diff) | |
bpf: Make BTF pointer type checking generic
Perform BTF type checks if the register we're working on contains a BTF
pointer, rather than if the argument is for a BTF pointer. This is easier
to understand, and allows removing the code from the arg_type checking
section of the function.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-6-lmb@cloudflare.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 38 |
1 files changed, 20 insertions, 18 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 30da34d9b93b..a0e919232968 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4048,27 +4048,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto err_type; } } else if (arg_type == ARG_PTR_TO_BTF_ID) { - const u32 *btf_id = fn->arg_btf_id[arg]; - expected_type = PTR_TO_BTF_ID; if (type != expected_type) goto err_type; - - if (!btf_id) { - verbose(env, "verifier internal error: missing BTF ID\n"); - return -EFAULT; - } - - if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, *btf_id)) { - verbose(env, "R%d is of type %s but %s is expected\n", - regno, kernel_type_name(reg->btf_id), kernel_type_name(*btf_id)); - return -EACCES; - } - if (!tnum_is_const(reg->var_off) || reg->var_off.value) { - verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", - regno); - return -EACCES; - } } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { if (meta->func_id == BPF_FUNC_spin_lock) { if (process_spin_lock(env, regno, true)) @@ -4123,6 +4105,26 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, return -EFAULT; } + if (type == PTR_TO_BTF_ID) { + const u32 *btf_id = fn->arg_btf_id[arg]; + + if (!btf_id) { + verbose(env, "verifier internal error: missing BTF ID\n"); + return -EFAULT; + } + + if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, *btf_id)) { + verbose(env, "R%d is of type %s but %s is expected\n", + regno, kernel_type_name(reg->btf_id), kernel_type_name(*btf_id)); + return -EACCES; + } + if (!tnum_is_const(reg->var_off) || reg->var_off.value) { + verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", + regno); + return -EACCES; + } + } + if (arg_type == ARG_CONST_MAP_PTR) { /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ meta->map_ptr = reg->map_ptr; |