From: Alexei Starovoitov Date: Fri, 3 Mar 2023 04:14:41 +0000 (-0800) Subject: bpf: Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted. X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=03b77e17aeb22a5935ea20d585ca6a1f2947e62b;p=linux.git bpf: Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted. __kptr meant to store PTR_UNTRUSTED kernel pointers inside bpf maps. The concept felt useful, but didn't get much traction, since bpf_rdonly_cast() was added soon after and bpf programs received a simpler way to access PTR_UNTRUSTED kernel pointers without going through restrictive __kptr usage. Rename __kptr_ref -> __kptr and __kptr -> __kptr_untrusted to indicate its intended usage. The main goal of __kptr_untrusted was to read/write such pointers directly while bpf_kptr_xchg was a mechanism to access refcnted kernel pointers. The next patch will allow RCU protected __kptr access with direct read. At that point __kptr_untrusted will be deprecated. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: David Vernet Link: https://lore.kernel.org/bpf/20230303041446.3630-2-alexei.starovoitov@gmail.com --- diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst index bfff0e7e37c2f..38372a956d651 100644 --- a/Documentation/bpf/bpf_design_QA.rst +++ b/Documentation/bpf/bpf_design_QA.rst @@ -314,7 +314,7 @@ Q: What is the compatibility story for special BPF types in map values? Q: Users are allowed to embed bpf_spin_lock, bpf_timer fields in their BPF map values (when using BTF support for BPF maps). This allows to use helpers for such objects on these fields inside map values. Users are also allowed to embed -pointers to some kernel types (with __kptr and __kptr_ref BTF tags). Will the +pointers to some kernel types (with __kptr_untrusted and __kptr BTF tags). Will the kernel preserve backwards compatibility for these features? A: It depends. For bpf_spin_lock, bpf_timer: YES, for kptr and everything else: @@ -324,7 +324,7 @@ For struct types that have been added already, like bpf_spin_lock and bpf_timer, the kernel will preserve backwards compatibility, as they are part of UAPI. For kptrs, they are also part of UAPI, but only with respect to the kptr -mechanism. The types that you can use with a __kptr and __kptr_ref tagged +mechanism. The types that you can use with a __kptr_untrusted and __kptr tagged pointer in your struct are NOT part of the UAPI contract. The supported types can and will change across kernel releases. However, operations like accessing kptr fields and bpf_kptr_xchg() helper will continue to be supported across kernel diff --git a/Documentation/bpf/cpumasks.rst b/Documentation/bpf/cpumasks.rst index 24bef9cbbeeea..75344cd230e55 100644 --- a/Documentation/bpf/cpumasks.rst +++ b/Documentation/bpf/cpumasks.rst @@ -51,7 +51,7 @@ For example: .. code-block:: c struct cpumask_map_value { - struct bpf_cpumask __kptr_ref * cpumask; + struct bpf_cpumask __kptr * cpumask; }; struct array_map { @@ -128,7 +128,7 @@ Here is an example of a ``struct bpf_cpumask *`` being retrieved from a map: /* struct containing the struct bpf_cpumask kptr which is stored in the map. */ struct cpumasks_kfunc_map_value { - struct bpf_cpumask __kptr_ref * bpf_cpumask; + struct bpf_cpumask __kptr * bpf_cpumask; }; /* The map containing struct cpumasks_kfunc_map_value entries. */ diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 9d85bbc3b7713..b5d9b0d446bce 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -544,7 +544,7 @@ Here's an example of how it can be used: /* struct containing the struct task_struct kptr which is actually stored in the map. */ struct __cgroups_kfunc_map_value { - struct cgroup __kptr_ref * cgroup; + struct cgroup __kptr * cgroup; }; /* The map containing struct __cgroups_kfunc_map_value entries. */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ef2d8969ed1f7..c5e1d6955491a 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3288,9 +3288,9 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, /* Reject extra tags */ if (btf_type_is_type_tag(btf_type_by_id(btf, t->type))) return -EINVAL; - if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off))) + if (!strcmp("kptr_untrusted", __btf_name_by_offset(btf, t->name_off))) type = BPF_KPTR_UNREF; - else if (!strcmp("kptr_ref", __btf_name_by_offset(btf, t->name_off))) + else if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off))) type = BPF_KPTR_REF; else return -EINVAL; diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 5ec1871acb2fc..7d12d3e620cc8 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -174,8 +174,8 @@ enum libbpf_tristate { #define __kconfig __attribute__((section(".kconfig"))) #define __ksym __attribute__((section(".ksyms"))) +#define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted"))) #define __kptr __attribute__((btf_type_tag("kptr"))) -#define __kptr_ref __attribute__((btf_type_tag("kptr_ref"))) #ifndef ___bpf_concat #define ___bpf_concat(a, b) a ## b diff --git a/tools/testing/selftests/bpf/progs/cb_refs.c b/tools/testing/selftests/bpf/progs/cb_refs.c index 7653df1bc7871..ce96b33e38d66 100644 --- a/tools/testing/selftests/bpf/progs/cb_refs.c +++ b/tools/testing/selftests/bpf/progs/cb_refs.c @@ -4,7 +4,7 @@ #include struct map_value { - struct prog_test_ref_kfunc __kptr_ref *ptr; + struct prog_test_ref_kfunc __kptr *ptr; }; struct { diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h index 2f8de933b957d..d0b7cd0d09d77 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h @@ -10,7 +10,7 @@ #include struct __cgrps_kfunc_map_value { - struct cgroup __kptr_ref * cgrp; + struct cgroup __kptr * cgrp; }; struct hash_map { diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h index ad34f3b602bee..65e5496ca1b22 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_common.h +++ b/tools/testing/selftests/bpf/progs/cpumask_common.h @@ -10,7 +10,7 @@ int err; struct __cpumask_map_value { - struct bpf_cpumask __kptr_ref * cpumask; + struct bpf_cpumask __kptr * cpumask; }; struct array_map { diff --git a/tools/testing/selftests/bpf/progs/jit_probe_mem.c b/tools/testing/selftests/bpf/progs/jit_probe_mem.c index 2d2e61470794b..13f00ca2ed0a0 100644 --- a/tools/testing/selftests/bpf/progs/jit_probe_mem.c +++ b/tools/testing/selftests/bpf/progs/jit_probe_mem.c @@ -4,7 +4,7 @@ #include #include -static struct prog_test_ref_kfunc __kptr_ref *v; +static struct prog_test_ref_kfunc __kptr *v; long total_sum = -1; extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym; diff --git a/tools/testing/selftests/bpf/progs/lru_bug.c b/tools/testing/selftests/bpf/progs/lru_bug.c index 687081a724b33..ad73029cb1e30 100644 --- a/tools/testing/selftests/bpf/progs/lru_bug.c +++ b/tools/testing/selftests/bpf/progs/lru_bug.c @@ -4,7 +4,7 @@ #include struct map_value { - struct task_struct __kptr *ptr; + struct task_struct __kptr_untrusted *ptr; }; struct { diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c index a24d17bc17eb7..3fe7cde4cbfd3 100644 --- a/tools/testing/selftests/bpf/progs/map_kptr.c +++ b/tools/testing/selftests/bpf/progs/map_kptr.c @@ -4,8 +4,8 @@ #include struct map_value { - struct prog_test_ref_kfunc __kptr *unref_ptr; - struct prog_test_ref_kfunc __kptr_ref *ref_ptr; + struct prog_test_ref_kfunc __kptr_untrusted *unref_ptr; + struct prog_test_ref_kfunc __kptr *ref_ptr; }; struct array_map { diff --git a/tools/testing/selftests/bpf/progs/map_kptr_fail.c b/tools/testing/selftests/bpf/progs/map_kptr_fail.c index 760e41e1a6326..e19e2a5f38cfb 100644 --- a/tools/testing/selftests/bpf/progs/map_kptr_fail.c +++ b/tools/testing/selftests/bpf/progs/map_kptr_fail.c @@ -7,9 +7,9 @@ struct map_value { char buf[8]; - struct prog_test_ref_kfunc __kptr *unref_ptr; - struct prog_test_ref_kfunc __kptr_ref *ref_ptr; - struct prog_test_member __kptr_ref *ref_memb_ptr; + struct prog_test_ref_kfunc __kptr_untrusted *unref_ptr; + struct prog_test_ref_kfunc __kptr *ref_ptr; + struct prog_test_member __kptr *ref_memb_ptr; }; struct array_map { diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_common.h b/tools/testing/selftests/bpf/progs/task_kfunc_common.h index c0ffd171743ed..4c2a4b0e3a251 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/task_kfunc_common.h @@ -10,7 +10,7 @@ #include struct __tasks_kfunc_map_value { - struct task_struct __kptr_ref * task; + struct task_struct __kptr * task; }; struct hash_map { diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 8b9949bb833d7..49a70d9beb0bc 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -699,13 +699,13 @@ static int create_cgroup_storage(bool percpu) * struct bpf_timer t; * }; * struct btf_ptr { + * struct prog_test_ref_kfunc __kptr_untrusted *ptr; * struct prog_test_ref_kfunc __kptr *ptr; - * struct prog_test_ref_kfunc __kptr_ref *ptr; - * struct prog_test_member __kptr_ref *ptr; + * struct prog_test_member __kptr *ptr; * } */ static const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l\0bpf_timer\0timer\0t" - "\0btf_ptr\0prog_test_ref_kfunc\0ptr\0kptr\0kptr_ref" + "\0btf_ptr\0prog_test_ref_kfunc\0ptr\0kptr\0kptr_untrusted" "\0prog_test_member"; static __u32 btf_raw_types[] = { /* int */ @@ -724,20 +724,20 @@ static __u32 btf_raw_types[] = { BTF_MEMBER_ENC(41, 4, 0), /* struct bpf_timer t; */ /* struct prog_test_ref_kfunc */ /* [6] */ BTF_STRUCT_ENC(51, 0, 0), - BTF_STRUCT_ENC(89, 0, 0), /* [7] */ + BTF_STRUCT_ENC(95, 0, 0), /* [7] */ + /* type tag "kptr_untrusted" */ + BTF_TYPE_TAG_ENC(80, 6), /* [8] */ /* type tag "kptr" */ - BTF_TYPE_TAG_ENC(75, 6), /* [8] */ - /* type tag "kptr_ref" */ - BTF_TYPE_TAG_ENC(80, 6), /* [9] */ - BTF_TYPE_TAG_ENC(80, 7), /* [10] */ + BTF_TYPE_TAG_ENC(75, 6), /* [9] */ + BTF_TYPE_TAG_ENC(75, 7), /* [10] */ BTF_PTR_ENC(8), /* [11] */ BTF_PTR_ENC(9), /* [12] */ BTF_PTR_ENC(10), /* [13] */ /* struct btf_ptr */ /* [14] */ BTF_STRUCT_ENC(43, 3, 24), - BTF_MEMBER_ENC(71, 11, 0), /* struct prog_test_ref_kfunc __kptr *ptr; */ - BTF_MEMBER_ENC(71, 12, 64), /* struct prog_test_ref_kfunc __kptr_ref *ptr; */ - BTF_MEMBER_ENC(71, 13, 128), /* struct prog_test_member __kptr_ref *ptr; */ + BTF_MEMBER_ENC(71, 11, 0), /* struct prog_test_ref_kfunc __kptr_untrusted *ptr; */ + BTF_MEMBER_ENC(71, 12, 64), /* struct prog_test_ref_kfunc __kptr *ptr; */ + BTF_MEMBER_ENC(71, 13, 128), /* struct prog_test_member __kptr *ptr; */ }; static char bpf_vlog[UINT_MAX >> 8];