| Message ID | 20200925000344.3854828-1-kafai@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | bpf: Enable bpf_skc_to_* sock casting helper to networking prog type | expand |
On Fri, 25 Sep 2020 at 01:03, Martin KaFai Lau <kafai@fb.com> wrote: > > check_reg_type() checks whether a reg can be used as an arg of a > func_proto. For PTR_TO_BTF_ID, the check is actually not > completely done until the reg->btf_id is pointing to a > kernel struct that is acceptable by the func_proto. > > Thus, this patch moves the btf_id check into check_reg_type(). > "arg_type" and "arg_btf_id" are passed to check_reg_type() instead of > "compatible". The compatible_reg_types[] usage is localized in > check_reg_type() now. > > The "if (!btf_id) verbose(...); " is also removed since it won't happen. > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Lorenz Bauer <lmb@cloudflare.com> > --- > kernel/bpf/verifier.c | 60 ++++++++++++++++++++++--------------------- > 1 file changed, 31 insertions(+), 29 deletions(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 42dee5dcbc74..945fa2b4d096 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -4028,19 +4028,27 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { > }; > > static int check_reg_type(struct bpf_verifier_env *env, u32 regno, > - const struct bpf_reg_types *compatible) > + enum bpf_arg_type arg_type, > + const u32 *arg_btf_id) > { > struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; > enum bpf_reg_type expected, type = reg->type; > + const struct bpf_reg_types *compatible; > int i, j; > > + compatible = compatible_reg_types[arg_type]; > + if (!compatible) { > + verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); > + return -EFAULT; > + } > + > for (i = 0; i < ARRAY_SIZE(compatible->types); i++) { > expected = compatible->types[i]; > if (expected == NOT_INIT) > break; > > if (type == expected) > - return 0; > + goto found; > } > > verbose(env, "R%d type=%s expected=", regno, reg_type_str[type]); > @@ -4048,6 +4056,25 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, > verbose(env, "%s, ", reg_type_str[compatible->types[j]]); > verbose(env, "%s\n", reg_type_str[compatible->types[j]]); > return -EACCES; > + > +found: > + if (type == PTR_TO_BTF_ID) { > + if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, > + *arg_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(*arg_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; > + } > + } > + > + return 0; > } > > static int check_func_arg(struct bpf_verifier_env *env, u32 arg, > @@ -4057,7 +4084,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, > u32 regno = BPF_REG_1 + arg; > struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; > enum bpf_arg_type arg_type = fn->arg_type[arg]; > - const struct bpf_reg_types *compatible; > enum bpf_reg_type type = reg->type; > int err = 0; > > @@ -4097,35 +4123,11 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, > */ > goto skip_type_check; > > - compatible = compatible_reg_types[arg_type]; > - if (!compatible) { > - verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); > - return -EFAULT; > - } > - > - err = check_reg_type(env, regno, compatible); > + err = check_reg_type(env, regno, arg_type, fn->arg_btf_id[arg]); > if (err) > return err; > > - 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; > - } > - } else if (type == PTR_TO_CTX) { > + if (type == PTR_TO_CTX) { > err = check_ctx_reg(env, reg, regno); > if (err < 0) > return err; > -- > 2.24.1 >
Martin KaFai Lau wrote: > check_reg_type() checks whether a reg can be used as an arg of a > func_proto. For PTR_TO_BTF_ID, the check is actually not > completely done until the reg->btf_id is pointing to a > kernel struct that is acceptable by the func_proto. > > Thus, this patch moves the btf_id check into check_reg_type(). > "arg_type" and "arg_btf_id" are passed to check_reg_type() instead of > "compatible". The compatible_reg_types[] usage is localized in > check_reg_type() now. > > The "if (!btf_id) verbose(...); " is also removed since it won't happen. > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > --- Acked-by: John Fastabend <john.fastabend@gmail.com>
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 42dee5dcbc74..945fa2b4d096 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4028,19 +4028,27 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { }; static int check_reg_type(struct bpf_verifier_env *env, u32 regno, - const struct bpf_reg_types *compatible) + enum bpf_arg_type arg_type, + const u32 *arg_btf_id) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; enum bpf_reg_type expected, type = reg->type; + const struct bpf_reg_types *compatible; int i, j; + compatible = compatible_reg_types[arg_type]; + if (!compatible) { + verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); + return -EFAULT; + } + for (i = 0; i < ARRAY_SIZE(compatible->types); i++) { expected = compatible->types[i]; if (expected == NOT_INIT) break; if (type == expected) - return 0; + goto found; } verbose(env, "R%d type=%s expected=", regno, reg_type_str[type]); @@ -4048,6 +4056,25 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, verbose(env, "%s, ", reg_type_str[compatible->types[j]]); verbose(env, "%s\n", reg_type_str[compatible->types[j]]); return -EACCES; + +found: + if (type == PTR_TO_BTF_ID) { + if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, + *arg_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(*arg_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; + } + } + + return 0; } static int check_func_arg(struct bpf_verifier_env *env, u32 arg, @@ -4057,7 +4084,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, u32 regno = BPF_REG_1 + arg; struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; enum bpf_arg_type arg_type = fn->arg_type[arg]; - const struct bpf_reg_types *compatible; enum bpf_reg_type type = reg->type; int err = 0; @@ -4097,35 +4123,11 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, */ goto skip_type_check; - compatible = compatible_reg_types[arg_type]; - if (!compatible) { - verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); - return -EFAULT; - } - - err = check_reg_type(env, regno, compatible); + err = check_reg_type(env, regno, arg_type, fn->arg_btf_id[arg]); if (err) return err; - 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; - } - } else if (type == PTR_TO_CTX) { + if (type == PTR_TO_CTX) { err = check_ctx_reg(env, reg, regno); if (err < 0) return err;
check_reg_type() checks whether a reg can be used as an arg of a func_proto. For PTR_TO_BTF_ID, the check is actually not completely done until the reg->btf_id is pointing to a kernel struct that is acceptable by the func_proto. Thus, this patch moves the btf_id check into check_reg_type(). "arg_type" and "arg_btf_id" are passed to check_reg_type() instead of "compatible". The compatible_reg_types[] usage is localized in check_reg_type() now. The "if (!btf_id) verbose(...); " is also removed since it won't happen. Signed-off-by: Martin KaFai Lau <kafai@fb.com> --- kernel/bpf/verifier.c | 60 ++++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 29 deletions(-)