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Message-ID: <20200109003503.3855825-1-kafai@fb.com>
Date: Wed, 8 Jan 2020 16:35:03 -0800
From: Martin KaFai Lau <kafai@...com>
To: <bpf@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
David Miller <davem@...emloft.net>, <kernel-team@...com>,
<netdev@...r.kernel.org>
Subject: [PATCH bpf-next v4 05/11] bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS
This patch allows the kernel's struct ops (i.e. func ptr) to be
implemented in BPF. The first use case in this series is the
"struct tcp_congestion_ops" which will be introduced in a
latter patch.
This patch introduces a new prog type BPF_PROG_TYPE_STRUCT_OPS.
The BPF_PROG_TYPE_STRUCT_OPS prog is verified against a particular
func ptr of a kernel struct. The attr->attach_btf_id is the btf id
of a kernel struct. The attr->expected_attach_type is the member
"index" of that kernel struct. The first member of a struct starts
with member index 0. That will avoid ambiguity when a kernel struct
has multiple func ptrs with the same func signature.
For example, a BPF_PROG_TYPE_STRUCT_OPS prog is written
to implement the "init" func ptr of the "struct tcp_congestion_ops".
The attr->attach_btf_id is the btf id of the "struct tcp_congestion_ops"
of the _running_ kernel. The attr->expected_attach_type is 3.
The ctx of BPF_PROG_TYPE_STRUCT_OPS is an array of u64 args saved
by arch_prepare_bpf_trampoline that will be done in the next
patch when introducing BPF_MAP_TYPE_STRUCT_OPS.
"struct bpf_struct_ops" is introduced as a common interface for the kernel
struct that supports BPF_PROG_TYPE_STRUCT_OPS prog. The supporting kernel
struct will need to implement an instance of the "struct bpf_struct_ops".
The supporting kernel struct also needs to implement a bpf_verifier_ops.
During BPF_PROG_LOAD, bpf_struct_ops_find() will find the right
bpf_verifier_ops by searching the attr->attach_btf_id.
A new "btf_struct_access" is also added to the bpf_verifier_ops such
that the supporting kernel struct can optionally provide its own specific
check on accessing the func arg (e.g. provide limited write access).
After btf_vmlinux is parsed, the new bpf_struct_ops_init() is called
to initialize some values (e.g. the btf id of the supporting kernel
struct) and it can only be done once the btf_vmlinux is available.
The R0 checks at BPF_EXIT is excluded for the BPF_PROG_TYPE_STRUCT_OPS prog
if the return type of the prog->aux->attach_func_proto is "void".
Acked-by: Andrii Nakryiko <andriin@...com>
Acked-by: Yonghong Song <yhs@...com>
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
include/linux/bpf.h | 30 +++++++
include/linux/bpf_types.h | 4 +
include/linux/btf.h | 34 ++++++++
include/uapi/linux/bpf.h | 1 +
kernel/bpf/Makefile | 3 +
kernel/bpf/bpf_struct_ops.c | 121 +++++++++++++++++++++++++++
kernel/bpf/bpf_struct_ops_types.h | 4 +
kernel/bpf/btf.c | 88 ++++++++++++++------
kernel/bpf/syscall.c | 17 ++--
kernel/bpf/verifier.c | 134 +++++++++++++++++++++++-------
10 files changed, 373 insertions(+), 63 deletions(-)
create mode 100644 kernel/bpf/bpf_struct_ops.c
create mode 100644 kernel/bpf/bpf_struct_ops_types.h
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b14e51d56a82..50f3b20ae284 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -349,6 +349,10 @@ struct bpf_verifier_ops {
const struct bpf_insn *src,
struct bpf_insn *dst,
struct bpf_prog *prog, u32 *target_size);
+ int (*btf_struct_access)(struct bpf_verifier_log *log,
+ const struct btf_type *t, int off, int size,
+ enum bpf_access_type atype,
+ u32 *next_btf_id);
};
struct bpf_prog_offload_ops {
@@ -668,6 +672,32 @@ struct bpf_array_aux {
struct work_struct work;
};
+struct btf_type;
+struct btf_member;
+
+#define BPF_STRUCT_OPS_MAX_NR_MEMBERS 64
+struct bpf_struct_ops {
+ const struct bpf_verifier_ops *verifier_ops;
+ int (*init)(struct btf *btf);
+ int (*check_member)(const struct btf_type *t,
+ const struct btf_member *member);
+ const struct btf_type *type;
+ const char *name;
+ struct btf_func_model func_models[BPF_STRUCT_OPS_MAX_NR_MEMBERS];
+ u32 type_id;
+};
+
+#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
+const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id);
+void bpf_struct_ops_init(struct btf *btf);
+#else
+static inline const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
+{
+ return NULL;
+}
+static inline void bpf_struct_ops_init(struct btf *btf) { }
+#endif
+
struct bpf_array {
struct bpf_map map;
u32 elem_size;
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 93740b3614d7..fadd243ffa2d 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -65,6 +65,10 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2,
BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport,
struct sk_reuseport_md, struct sk_reuseport_kern)
#endif
+#if defined(CONFIG_BPF_JIT)
+BPF_PROG_TYPE(BPF_PROG_TYPE_STRUCT_OPS, bpf_struct_ops,
+ void *, void *)
+#endif
BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 79d4abc2556a..f74a09a7120b 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -53,6 +53,18 @@ bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
u32 expected_offset, u32 expected_size);
int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
bool btf_type_is_void(const struct btf_type *t);
+s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
+const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
+ u32 id, u32 *res_id);
+const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
+ u32 id, u32 *res_id);
+const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
+ u32 id, u32 *res_id);
+
+#define for_each_member(i, struct_type, member) \
+ for (i = 0, member = btf_type_member(struct_type); \
+ i < btf_type_vlen(struct_type); \
+ i++, member++)
static inline bool btf_type_is_ptr(const struct btf_type *t)
{
@@ -84,6 +96,28 @@ static inline bool btf_type_is_func_proto(const struct btf_type *t)
return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
}
+static inline u16 btf_type_vlen(const struct btf_type *t)
+{
+ return BTF_INFO_VLEN(t->info);
+}
+
+static inline bool btf_type_kflag(const struct btf_type *t)
+{
+ return BTF_INFO_KFLAG(t->info);
+}
+
+static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type,
+ const struct btf_member *member)
+{
+ return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
+ : 0;
+}
+
+static inline const struct btf_member *btf_type_member(const struct btf_type *t)
+{
+ return (const struct btf_member *)(t + 1);
+}
+
#ifdef CONFIG_BPF_SYSCALL
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
const char *btf_name_by_offset(const struct btf *btf, u32 offset);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7df436da542d..c1eeb3e0e116 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -174,6 +174,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_PROG_TYPE_TRACING,
+ BPF_PROG_TYPE_STRUCT_OPS,
};
enum bpf_attach_type {
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index d4f330351f87..046ce5d98033 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -27,3 +27,6 @@ endif
ifeq ($(CONFIG_SYSFS),y)
obj-$(CONFIG_DEBUG_INFO_BTF) += sysfs_btf.o
endif
+ifeq ($(CONFIG_BPF_JIT),y)
+obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o
+endif
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
new file mode 100644
index 000000000000..2ea68fe34c33
--- /dev/null
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+
+#include <linux/bpf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+#include <linux/filter.h>
+#include <linux/slab.h>
+#include <linux/numa.h>
+#include <linux/seq_file.h>
+#include <linux/refcount.h>
+
+#define BPF_STRUCT_OPS_TYPE(_name) \
+extern struct bpf_struct_ops bpf_##_name;
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+
+enum {
+#define BPF_STRUCT_OPS_TYPE(_name) BPF_STRUCT_OPS_TYPE_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+ __NR_BPF_STRUCT_OPS_TYPE,
+};
+
+static struct bpf_struct_ops * const bpf_struct_ops[] = {
+#define BPF_STRUCT_OPS_TYPE(_name) \
+ [BPF_STRUCT_OPS_TYPE_##_name] = &bpf_##_name,
+#include "bpf_struct_ops_types.h"
+#undef BPF_STRUCT_OPS_TYPE
+};
+
+const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
+};
+
+const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
+};
+
+void bpf_struct_ops_init(struct btf *btf)
+{
+ const struct btf_member *member;
+ struct bpf_struct_ops *st_ops;
+ struct bpf_verifier_log log = {};
+ const struct btf_type *t;
+ const char *mname;
+ s32 type_id;
+ u32 i, j;
+
+ for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ st_ops = bpf_struct_ops[i];
+
+ type_id = btf_find_by_name_kind(btf, st_ops->name,
+ BTF_KIND_STRUCT);
+ if (type_id < 0) {
+ pr_warn("Cannot find struct %s in btf_vmlinux\n",
+ st_ops->name);
+ continue;
+ }
+ t = btf_type_by_id(btf, type_id);
+ if (btf_type_vlen(t) > BPF_STRUCT_OPS_MAX_NR_MEMBERS) {
+ pr_warn("Cannot support #%u members in struct %s\n",
+ btf_type_vlen(t), st_ops->name);
+ continue;
+ }
+
+ for_each_member(j, t, member) {
+ const struct btf_type *func_proto;
+
+ mname = btf_name_by_offset(btf, member->name_off);
+ if (!*mname) {
+ pr_warn("anon member in struct %s is not supported\n",
+ st_ops->name);
+ break;
+ }
+
+ if (btf_member_bitfield_size(t, member)) {
+ pr_warn("bit field member %s in struct %s is not supported\n",
+ mname, st_ops->name);
+ break;
+ }
+
+ func_proto = btf_type_resolve_func_ptr(btf,
+ member->type,
+ NULL);
+ if (func_proto &&
+ btf_distill_func_proto(&log, btf,
+ func_proto, mname,
+ &st_ops->func_models[j])) {
+ pr_warn("Error in parsing func ptr %s in struct %s\n",
+ mname, st_ops->name);
+ break;
+ }
+ }
+
+ if (j == btf_type_vlen(t)) {
+ if (st_ops->init(btf)) {
+ pr_warn("Error in init bpf_struct_ops %s\n",
+ st_ops->name);
+ } else {
+ st_ops->type_id = type_id;
+ st_ops->type = t;
+ }
+ }
+ }
+}
+
+extern struct btf *btf_vmlinux;
+
+const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
+{
+ unsigned int i;
+
+ if (!type_id || !btf_vmlinux)
+ return NULL;
+
+ for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
+ if (bpf_struct_ops[i]->type_id == type_id)
+ return bpf_struct_ops[i];
+ }
+
+ return NULL;
+}
diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
new file mode 100644
index 000000000000..7bb13ff49ec2
--- /dev/null
+++ b/kernel/bpf/bpf_struct_ops_types.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* internal file - do not include directly */
+
+/* To be filled in a later patch */
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 48bbde2e1c1e..12af4a1bb1a4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -180,11 +180,6 @@
*/
#define BTF_MAX_SIZE (16 * 1024 * 1024)
-#define for_each_member(i, struct_type, member) \
- for (i = 0, member = btf_type_member(struct_type); \
- i < btf_type_vlen(struct_type); \
- i++, member++)
-
#define for_each_member_from(i, from, struct_type, member) \
for (i = from, member = btf_type_member(struct_type) + from; \
i < btf_type_vlen(struct_type); \
@@ -382,6 +377,65 @@ static bool btf_type_is_datasec(const struct btf_type *t)
return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
}
+s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
+{
+ const struct btf_type *t;
+ const char *tname;
+ u32 i;
+
+ for (i = 1; i <= btf->nr_types; i++) {
+ t = btf->types[i];
+ if (BTF_INFO_KIND(t->info) != kind)
+ continue;
+
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (!strcmp(tname, name))
+ return i;
+ }
+
+ return -ENOENT;
+}
+
+const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
+ u32 id, u32 *res_id)
+{
+ const struct btf_type *t = btf_type_by_id(btf, id);
+
+ while (btf_type_is_modifier(t)) {
+ id = t->type;
+ t = btf_type_by_id(btf, t->type);
+ }
+
+ if (res_id)
+ *res_id = id;
+
+ return t;
+}
+
+const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
+ u32 id, u32 *res_id)
+{
+ const struct btf_type *t;
+
+ t = btf_type_skip_modifiers(btf, id, NULL);
+ if (!btf_type_is_ptr(t))
+ return NULL;
+
+ return btf_type_skip_modifiers(btf, t->type, res_id);
+}
+
+const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
+ u32 id, u32 *res_id)
+{
+ const struct btf_type *ptype;
+
+ ptype = btf_type_resolve_ptr(btf, id, res_id);
+ if (ptype && btf_type_is_func_proto(ptype))
+ return ptype;
+
+ return NULL;
+}
+
/* Types that act only as a source, not sink or intermediate
* type when resolving.
*/
@@ -446,16 +500,6 @@ static const char *btf_int_encoding_str(u8 encoding)
return "UNKN";
}
-static u16 btf_type_vlen(const struct btf_type *t)
-{
- return BTF_INFO_VLEN(t->info);
-}
-
-static bool btf_type_kflag(const struct btf_type *t)
-{
- return BTF_INFO_KFLAG(t->info);
-}
-
static u32 btf_member_bit_offset(const struct btf_type *struct_type,
const struct btf_member *member)
{
@@ -463,13 +507,6 @@ static u32 btf_member_bit_offset(const struct btf_type *struct_type,
: member->offset;
}
-static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
- const struct btf_member *member)
-{
- return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
- : 0;
-}
-
static u32 btf_type_int(const struct btf_type *t)
{
return *(u32 *)(t + 1);
@@ -480,11 +517,6 @@ static const struct btf_array *btf_type_array(const struct btf_type *t)
return (const struct btf_array *)(t + 1);
}
-static const struct btf_member *btf_type_member(const struct btf_type *t)
-{
- return (const struct btf_member *)(t + 1);
-}
-
static const struct btf_enum *btf_type_enum(const struct btf_type *t)
{
return (const struct btf_enum *)(t + 1);
@@ -3605,6 +3637,8 @@ struct btf *btf_parse_vmlinux(void)
goto errout;
}
+ bpf_struct_ops_init(btf);
+
btf_verifier_env_free(env);
refcount_set(&btf->refcnt, 1);
return btf;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 81ee8595dfee..03a02ef4c496 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1672,17 +1672,22 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
enum bpf_attach_type expected_attach_type,
u32 btf_id, u32 prog_fd)
{
- switch (prog_type) {
- case BPF_PROG_TYPE_TRACING:
+ if (btf_id) {
if (btf_id > BTF_MAX_TYPE)
return -EINVAL;
- break;
- default:
- if (btf_id || prog_fd)
+
+ switch (prog_type) {
+ case BPF_PROG_TYPE_TRACING:
+ case BPF_PROG_TYPE_STRUCT_OPS:
+ break;
+ default:
return -EINVAL;
- break;
+ }
}
+ if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING)
+ return -EINVAL;
+
switch (prog_type) {
case BPF_PROG_TYPE_CGROUP_SOCK:
switch (expected_attach_type) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d433d70022fd..586ed3c94b80 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2859,11 +2859,6 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
u32 btf_id;
int ret;
- if (atype != BPF_READ) {
- verbose(env, "only read is supported\n");
- return -EACCES;
- }
-
if (off < 0) {
verbose(env,
"R%d is ptr_%s invalid negative access: off=%d\n",
@@ -2880,17 +2875,32 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
return -EACCES;
}
- ret = btf_struct_access(&env->log, t, off, size, atype, &btf_id);
+ if (env->ops->btf_struct_access) {
+ ret = env->ops->btf_struct_access(&env->log, t, off, size,
+ atype, &btf_id);
+ } else {
+ if (atype != BPF_READ) {
+ verbose(env, "only read is supported\n");
+ return -EACCES;
+ }
+
+ ret = btf_struct_access(&env->log, t, off, size, atype,
+ &btf_id);
+ }
+
if (ret < 0)
return ret;
- if (ret == SCALAR_VALUE) {
- mark_reg_unknown(env, regs, value_regno);
- return 0;
+ if (atype == BPF_READ) {
+ if (ret == SCALAR_VALUE) {
+ mark_reg_unknown(env, regs, value_regno);
+ return 0;
+ }
+ mark_reg_known_zero(env, regs, value_regno);
+ regs[value_regno].type = PTR_TO_BTF_ID;
+ regs[value_regno].btf_id = btf_id;
}
- mark_reg_known_zero(env, regs, value_regno);
- regs[value_regno].type = PTR_TO_BTF_ID;
- regs[value_regno].btf_id = btf_id;
+
return 0;
}
@@ -6349,8 +6359,30 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
static int check_return_code(struct bpf_verifier_env *env)
{
struct tnum enforce_attach_type_range = tnum_unknown;
+ const struct bpf_prog *prog = env->prog;
struct bpf_reg_state *reg;
struct tnum range = tnum_range(0, 1);
+ int err;
+
+ /* The struct_ops func-ptr's return type could be "void" */
+ if (env->prog->type == BPF_PROG_TYPE_STRUCT_OPS &&
+ !prog->aux->attach_func_proto->type)
+ return 0;
+
+ /* eBPF calling convetion is such that R0 is used
+ * to return the value from eBPF program.
+ * Make sure that it's readable at this time
+ * of bpf_exit, which means that program wrote
+ * something into it earlier
+ */
+ err = check_reg_arg(env, BPF_REG_0, SRC_OP);
+ if (err)
+ return err;
+
+ if (is_pointer_value(env, BPF_REG_0)) {
+ verbose(env, "R0 leaks addr as return value\n");
+ return -EACCES;
+ }
switch (env->prog->type) {
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
@@ -8016,21 +8048,6 @@ static int do_check(struct bpf_verifier_env *env)
if (err)
return err;
- /* eBPF calling convetion is such that R0 is used
- * to return the value from eBPF program.
- * Make sure that it's readable at this time
- * of bpf_exit, which means that program wrote
- * something into it earlier
- */
- err = check_reg_arg(env, BPF_REG_0, SRC_OP);
- if (err)
- return err;
-
- if (is_pointer_value(env, BPF_REG_0)) {
- verbose(env, "R0 leaks addr as return value\n");
- return -EACCES;
- }
-
err = check_return_code(env);
if (err)
return err;
@@ -8829,12 +8846,14 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
break;
case PTR_TO_BTF_ID:
- if (type == BPF_WRITE) {
+ if (type == BPF_READ) {
+ insn->code = BPF_LDX | BPF_PROBE_MEM |
+ BPF_SIZE((insn)->code);
+ env->prog->aux->num_exentries++;
+ } else if (env->prog->type != BPF_PROG_TYPE_STRUCT_OPS) {
verbose(env, "Writes through BTF pointers are not allowed\n");
return -EINVAL;
}
- insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code);
- env->prog->aux->num_exentries++;
continue;
default:
continue;
@@ -9502,6 +9521,58 @@ static void print_verification_stats(struct bpf_verifier_env *env)
env->peak_states, env->longest_mark_read_walk);
}
+static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
+{
+ const struct btf_type *t, *func_proto;
+ const struct bpf_struct_ops *st_ops;
+ const struct btf_member *member;
+ struct bpf_prog *prog = env->prog;
+ u32 btf_id, member_idx;
+ const char *mname;
+
+ btf_id = prog->aux->attach_btf_id;
+ st_ops = bpf_struct_ops_find(btf_id);
+ if (!st_ops) {
+ verbose(env, "attach_btf_id %u is not a supported struct\n",
+ btf_id);
+ return -ENOTSUPP;
+ }
+
+ t = st_ops->type;
+ member_idx = prog->expected_attach_type;
+ if (member_idx >= btf_type_vlen(t)) {
+ verbose(env, "attach to invalid member idx %u of struct %s\n",
+ member_idx, st_ops->name);
+ return -EINVAL;
+ }
+
+ member = &btf_type_member(t)[member_idx];
+ mname = btf_name_by_offset(btf_vmlinux, member->name_off);
+ func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
+ NULL);
+ if (!func_proto) {
+ verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
+ mname, member_idx, st_ops->name);
+ return -EINVAL;
+ }
+
+ if (st_ops->check_member) {
+ int err = st_ops->check_member(t, member);
+
+ if (err) {
+ verbose(env, "attach to unsupported member %s of struct %s\n",
+ mname, st_ops->name);
+ return err;
+ }
+ }
+
+ prog->aux->attach_func_proto = func_proto;
+ prog->aux->attach_func_name = mname;
+ env->ops = st_ops->verifier_ops;
+
+ return 0;
+}
+
static int check_attach_btf_id(struct bpf_verifier_env *env)
{
struct bpf_prog *prog = env->prog;
@@ -9517,6 +9588,9 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
long addr;
u64 key;
+ if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
+ return check_struct_ops_btf_id(env);
+
if (prog->type != BPF_PROG_TYPE_TRACING)
return 0;
--
2.17.1
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