From: Yonghong Song <yhs@fb.com>
To: Andrii Nakryiko <andriin@fb.com>, <bpf@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>, <netdev@vger.kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: [PATCH bpf-next v2 02/20] bpf: allow loading of a bpf_iter program
Date: Sun, 3 May 2020 23:25:48 -0700 [thread overview]
Message-ID: <20200504062548.2047454-1-yhs@fb.com> (raw)
In-Reply-To: <20200504062547.2047304-1-yhs@fb.com>
A bpf_iter program is a tracing program with attach type
BPF_TRACE_ITER. The load attribute
attach_btf_id
is used by the verifier against a particular kernel function,
which represents a target, e.g., __bpf_iter__bpf_map
for target bpf_map which is implemented later.
The program return value must be 0 or 1 for now.
0 : successful, except potential seq_file buffer overflow
which is handled by seq_file reader.
1 : request to restart the same object
In the future, other return values may be used for filtering or
teminating the iterator.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
include/linux/bpf.h | 3 +++
include/uapi/linux/bpf.h | 1 +
kernel/bpf/bpf_iter.c | 30 ++++++++++++++++++++++++++++++
kernel/bpf/verifier.c | 21 +++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 1 +
5 files changed, 56 insertions(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 597b37c4e1c6..cd385c36a172 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1127,6 +1127,8 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd);
int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
int bpf_obj_get_user(const char __user *pathname, int flags);
+#define BPF_ITER_FUNC_PREFIX "__bpf_iter__"
+
typedef int (*bpf_iter_init_seq_priv_t)(void *private_data);
typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data);
@@ -1139,6 +1141,7 @@ struct bpf_iter_reg {
};
int bpf_iter_reg_target(struct bpf_iter_reg *reg_info);
+bool bpf_iter_prog_supported(struct bpf_prog *prog);
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index b3643e27e264..047b19fe716e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -218,6 +218,7 @@ enum bpf_attach_type {
BPF_TRACE_FEXIT,
BPF_MODIFY_RETURN,
BPF_LSM_MAC,
+ BPF_TRACE_ITER,
__MAX_BPF_ATTACH_TYPE
};
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index ed930a0470e9..c1fae67a1452 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -12,6 +12,7 @@ struct bpf_iter_target_info {
bpf_iter_init_seq_priv_t init_seq_private;
bpf_iter_fini_seq_priv_t fini_seq_private;
u32 seq_priv_size;
+ u32 btf_id;
};
static struct list_head targets = LIST_HEAD_INIT(targets);
@@ -38,3 +39,32 @@ int bpf_iter_reg_target(struct bpf_iter_reg *reg_info)
return 0;
}
+
+bool bpf_iter_prog_supported(struct bpf_prog *prog)
+{
+ const char *attach_fname = prog->aux->attach_func_name;
+ u32 prog_btf_id = prog->aux->attach_btf_id;
+ const char *prefix = BPF_ITER_FUNC_PREFIX;
+ struct bpf_iter_target_info *tinfo;
+ int prefix_len = strlen(prefix);
+ bool supported = false;
+
+ if (strncmp(attach_fname, prefix, prefix_len))
+ return false;
+
+ mutex_lock(&targets_mutex);
+ list_for_each_entry(tinfo, &targets, list) {
+ if (tinfo->btf_id && tinfo->btf_id == prog_btf_id) {
+ supported = true;
+ break;
+ }
+ if (!strcmp(attach_fname + prefix_len, tinfo->target)) {
+ tinfo->btf_id = prog->aux->attach_btf_id;
+ supported = true;
+ break;
+ }
+ }
+ mutex_unlock(&targets_mutex);
+
+ return supported;
+}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 70ad009577f8..d725ff7d11db 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7101,6 +7101,10 @@ static int check_return_code(struct bpf_verifier_env *env)
return 0;
range = tnum_const(0);
break;
+ case BPF_PROG_TYPE_TRACING:
+ if (env->prog->expected_attach_type != BPF_TRACE_ITER)
+ return 0;
+ break;
default:
return 0;
}
@@ -10481,6 +10485,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
struct bpf_prog *tgt_prog = prog->aux->linked_prog;
u32 btf_id = prog->aux->attach_btf_id;
const char prefix[] = "btf_trace_";
+ struct btf_func_model fmodel;
int ret = 0, subprog = -1, i;
struct bpf_trampoline *tr;
const struct btf_type *t;
@@ -10622,6 +10627,22 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->aux->attach_func_proto = t;
prog->aux->attach_btf_trace = true;
return 0;
+ case BPF_TRACE_ITER:
+ if (!btf_type_is_func(t)) {
+ verbose(env, "attach_btf_id %u is not a function\n",
+ btf_id);
+ return -EINVAL;
+ }
+ t = btf_type_by_id(btf, t->type);
+ if (!btf_type_is_func_proto(t))
+ return -EINVAL;
+ prog->aux->attach_func_name = tname;
+ prog->aux->attach_func_proto = t;
+ if (!bpf_iter_prog_supported(prog))
+ return -EINVAL;
+ ret = btf_distill_func_proto(&env->log, btf, t,
+ tname, &fmodel);
+ return ret;
default:
if (!prog_extension)
return -EINVAL;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index b3643e27e264..047b19fe716e 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -218,6 +218,7 @@ enum bpf_attach_type {
BPF_TRACE_FEXIT,
BPF_MODIFY_RETURN,
BPF_LSM_MAC,
+ BPF_TRACE_ITER,
__MAX_BPF_ATTACH_TYPE
};
--
2.24.1
next prev parent reply other threads:[~2020-05-04 6:25 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-04 6:25 [PATCH bpf-next v2 00/20] bpf: implement bpf iterator for kernel data Yonghong Song
2020-05-04 6:25 ` [PATCH bpf-next v2 01/20] bpf: implement an interface to register bpf_iter targets Yonghong Song
2020-05-05 21:19 ` Andrii Nakryiko
2020-05-04 6:25 ` Yonghong Song [this message]
2020-05-05 21:29 ` [PATCH bpf-next v2 02/20] bpf: allow loading of a bpf_iter program Andrii Nakryiko
2020-05-06 0:07 ` Yonghong Song
2020-05-04 6:25 ` [PATCH bpf-next v2 03/20] bpf: support bpf tracing/iter programs for BPF_LINK_CREATE Yonghong Song
2020-05-05 21:30 ` Andrii Nakryiko
2020-05-06 0:14 ` Yonghong Song
2020-05-06 0:54 ` Alexei Starovoitov
2020-05-06 3:09 ` Andrii Nakryiko
2020-05-06 18:08 ` Alexei Starovoitov
2020-05-04 6:25 ` [PATCH bpf-next v2 04/20] bpf: support bpf tracing/iter programs for BPF_LINK_UPDATE Yonghong Song
2020-05-05 21:32 ` Andrii Nakryiko
2020-05-04 6:25 ` [PATCH bpf-next v2 05/20] bpf: implement bpf_seq_read() for bpf iterator Yonghong Song
2020-05-05 19:56 ` Andrii Nakryiko
2020-05-05 19:57 ` Alexei Starovoitov
2020-05-05 20:25 ` Yonghong Song
2020-05-05 21:08 ` Andrii Nakryiko
2020-05-04 6:25 ` [PATCH bpf-next v2 06/20] bpf: create anonymous " Yonghong Song
2020-05-05 20:11 ` Andrii Nakryiko
2020-05-05 20:28 ` Yonghong Song
2020-05-04 6:25 ` [PATCH bpf-next v2 07/20] bpf: create file " Yonghong Song
2020-05-05 20:15 ` Andrii Nakryiko
2020-05-04 6:25 ` [PATCH bpf-next v2 08/20] bpf: implement common macros/helpers for target iterators Yonghong Song
2020-05-05 20:25 ` Andrii Nakryiko
2020-05-05 20:30 ` Yonghong Song
2020-05-05 21:10 ` Andrii Nakryiko
2020-05-04 6:25 ` [PATCH bpf-next v2 09/20] bpf: add bpf_map iterator Yonghong Song
2020-05-06 5:11 ` Andrii Nakryiko
2020-05-04 6:25 ` [PATCH bpf-next v2 10/20] net: bpf: add netlink and ipv6_route bpf_iter targets Yonghong Song
2020-05-06 5:21 ` Andrii Nakryiko
2020-05-06 17:32 ` Yonghong Song
2020-05-04 6:25 ` [PATCH bpf-next v2 11/20] bpf: add task and task/file iterator targets Yonghong Song
2020-05-06 7:30 ` Andrii Nakryiko
2020-05-06 18:24 ` Yonghong Song
2020-05-06 20:51 ` Andrii Nakryiko
2020-05-06 21:20 ` Yonghong Song
2020-05-04 6:26 ` [PATCH bpf-next v2 12/20] bpf: add PTR_TO_BTF_ID_OR_NULL support Yonghong Song
2020-05-05 20:27 ` Andrii Nakryiko
2020-05-04 6:26 ` [PATCH bpf-next v2 13/20] bpf: add bpf_seq_printf and bpf_seq_write helpers Yonghong Song
2020-05-06 17:37 ` Andrii Nakryiko
2020-05-06 21:42 ` Yonghong Song
2020-05-08 18:15 ` Andrii Nakryiko
2020-05-04 6:26 ` [PATCH bpf-next v2 14/20] bpf: handle spilled PTR_TO_BTF_ID properly when checking stack_boundary Yonghong Song
2020-05-06 17:38 ` Andrii Nakryiko
2020-05-06 21:47 ` Yonghong Song
2020-05-04 6:26 ` [PATCH bpf-next v2 15/20] bpf: support variable length array in tracing programs Yonghong Song
2020-05-06 17:40 ` Andrii Nakryiko
2020-05-04 6:26 ` [PATCH bpf-next v2 16/20] tools/libbpf: add bpf_iter support Yonghong Song
2020-05-06 5:44 ` Andrii Nakryiko
2020-05-04 6:26 ` [PATCH bpf-next v2 17/20] tools/bpftool: add bpf_iter support for bptool Yonghong Song
2020-05-04 6:26 ` [PATCH bpf-next v2 18/20] tools/bpf: selftests: add iterator programs for ipv6_route and netlink Yonghong Song
2020-05-06 6:01 ` Andrii Nakryiko
2020-05-07 1:09 ` Yonghong Song
2020-05-08 18:17 ` Andrii Nakryiko
2020-05-06 6:04 ` Andrii Nakryiko
2020-05-06 23:07 ` Yonghong Song
2020-05-04 6:26 ` [PATCH bpf-next v2 19/20] tools/bpf: selftests: add iter progs for bpf_map/task/task_file Yonghong Song
2020-05-06 6:14 ` Andrii Nakryiko
2020-05-04 6:26 ` [PATCH bpf-next v2 20/20] tools/bpf: selftests: add bpf_iter selftests Yonghong Song
2020-05-06 6:39 ` Andrii Nakryiko
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