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bpf: Make reference tracking generic 

Instead of dealing with reg->ref_obj_id individually for every arg type that
needs it, rely on the fact that ref_obj_id is zero if the register is not
reference tracked.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-7-lmb@cloudflare.com
This commit is contained in:
Lorenz Bauer 2020-09-21 13:12:22 +01:00 committed by Alexei Starovoitov
parent d7b9454a4f
commit 02f7c9585d
1 changed files with 10 additions and 16 deletions
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26
kernel/bpf/verifier.c
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@ -4030,15 +4030,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
/* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
if (!type_is_sk_pointer(type))
goto err_type;
if (reg->ref_obj_id) {
if (meta->ref_obj_id) {
verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
regno, reg->ref_obj_id,
meta->ref_obj_id);
return -EFAULT;
}
meta->ref_obj_id = reg->ref_obj_id;
}
} else if (arg_type == ARG_PTR_TO_SOCKET ||
arg_type == ARG_PTR_TO_SOCKET_OR_NULL) {
expected_type = PTR_TO_SOCKET;
@ -4087,13 +4078,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
/* final test in check_stack_boundary() */;
else if (type != expected_type)
goto err_type;
if (meta->ref_obj_id) {
verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
regno, reg->ref_obj_id,
meta->ref_obj_id);
return -EFAULT;
}
meta->ref_obj_id = reg->ref_obj_id;
} else if (arg_type_is_int_ptr(arg_type)) {
expected_type = PTR_TO_STACK;
if (!type_is_pkt_pointer(type) &&
@ -4125,6 +4109,16 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
}
}
if (reg->ref_obj_id) {
if (meta->ref_obj_id) {
verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
regno, reg->ref_obj_id,
meta->ref_obj_id);
return -EFAULT;
}
meta->ref_obj_id = reg->ref_obj_id;
}
if (arg_type == ARG_CONST_MAP_PTR) {
/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
meta->map_ptr = reg->map_ptr;