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Date: Fri, 29 Apr 2022 14:15:35 -0700
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
Stanislav Fomichev <sdf@...gle.com>
Subject: [PATCH bpf-next v6 05/10] bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP
We have two options:
1. Treat all BPF_LSM_CGROUP as the same, regardless of attach_btf_id
2. Treat BPF_LSM_CGROUP+attach_btf_id as a separate hook point
I'm doing (2) here and adding attach_btf_id as a new BPF_PROG_QUERY
argument. The downside is that it requires iterating over all possible
bpf_lsm_ hook points in the userspace which might take some time.
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
include/uapi/linux/bpf.h | 1 +
kernel/bpf/cgroup.c | 43 ++++++++++++++++++++++++----------
kernel/bpf/syscall.c | 3 ++-
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/bpf.c | 42 ++++++++++++++++++++++++++-------
tools/lib/bpf/bpf.h | 15 ++++++++++++
tools/lib/bpf/libbpf.map | 1 +
7 files changed, 85 insertions(+), 21 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 112e396bbe65..e38ea0b47b6a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1431,6 +1431,7 @@ union bpf_attr {
__u32 attach_flags;
__aligned_u64 prog_ids;
__u32 prog_cnt;
+ __u32 attach_btf_id; /* for BPF_LSM_CGROUP */
} query;
struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 787ff6cf8d42..0add465c06b9 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1051,9 +1051,15 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
int cnt, ret = 0, i;
u32 flags;
- atype = to_cgroup_bpf_attach_type(type);
- if (atype < 0)
- return -EINVAL;
+ if (type == BPF_LSM_CGROUP) {
+ atype = bpf_lsm_attach_type_get(attr->query.attach_btf_id);
+ if (atype < 0)
+ return atype;
+ } else {
+ atype = to_cgroup_bpf_attach_type(type);
+ if (atype < 0)
+ return -EINVAL;
+ }
progs = &cgrp->bpf.progs[atype];
flags = cgrp->bpf.flags[atype];
@@ -1066,20 +1072,26 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
else
cnt = prog_list_length(progs);
- if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
- return -EFAULT;
- if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt)))
- return -EFAULT;
- if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)
+ if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {
+ ret = -EFAULT;
+ goto cleanup_attach_type;
+ }
+ if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {
+ ret = -EFAULT;
+ goto cleanup_attach_type;
+ }
+ if (attr->query.prog_cnt == 0 || !prog_ids || !cnt) {
/* return early if user requested only program count + flags */
- return 0;
+ ret = 0;
+ goto cleanup_attach_type;
+ }
if (attr->query.prog_cnt < cnt) {
cnt = attr->query.prog_cnt;
ret = -ENOSPC;
}
if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {
- return bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
+ ret = bpf_prog_array_copy_to_user(effective, prog_ids, cnt);
} else {
struct bpf_prog_list *pl;
u32 id;
@@ -1088,12 +1100,19 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
hlist_for_each_entry(pl, progs, node) {
prog = prog_list_prog(pl);
id = prog->aux->id;
- if (copy_to_user(prog_ids + i, &id, sizeof(id)))
- return -EFAULT;
+ if (copy_to_user(prog_ids + i, &id, sizeof(id))) {
+ ret = -EFAULT;
+ goto cleanup_attach_type;
+ }
if (++i == cnt)
break;
}
}
+
+cleanup_attach_type:
+ if (type == BPF_LSM_CGROUP)
+ bpf_lsm_attach_type_put(attr->query.attach_btf_id);
+
return ret;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 53fe0ae9f8cf..cdf1937b71ca 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3525,7 +3525,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
}
}
-#define BPF_PROG_QUERY_LAST_FIELD query.prog_cnt
+#define BPF_PROG_QUERY_LAST_FIELD query.attach_btf_id
static int bpf_prog_query(const union bpf_attr *attr,
union bpf_attr __user *uattr)
@@ -3561,6 +3561,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
case BPF_CGROUP_SYSCTL:
case BPF_CGROUP_GETSOCKOPT:
case BPF_CGROUP_SETSOCKOPT:
+ case BPF_LSM_CGROUP:
return cgroup_bpf_prog_query(attr, uattr);
case BPF_LIRC_MODE2:
return lirc_prog_query(attr, uattr);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 112e396bbe65..e38ea0b47b6a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1431,6 +1431,7 @@ union bpf_attr {
__u32 attach_flags;
__aligned_u64 prog_ids;
__u32 prog_cnt;
+ __u32 attach_btf_id; /* for BPF_LSM_CGROUP */
} query;
struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index a9d292c106c2..f62823451b99 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -946,28 +946,54 @@ int bpf_iter_create(int link_fd)
return libbpf_err_errno(fd);
}
-int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
- __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
+int bpf_prog_query2(int target_fd,
+ enum bpf_attach_type type,
+ struct bpf_prog_query_opts *opts)
{
union bpf_attr attr;
int ret;
memset(&attr, 0, sizeof(attr));
+
+ if (!OPTS_VALID(opts, bpf_prog_query_opts))
+ return libbpf_err(-EINVAL);
+
attr.query.target_fd = target_fd;
attr.query.attach_type = type;
- attr.query.query_flags = query_flags;
- attr.query.prog_cnt = *prog_cnt;
- attr.query.prog_ids = ptr_to_u64(prog_ids);
+ attr.query.query_flags = OPTS_GET(opts, query_flags, 0);
+ attr.query.prog_cnt = OPTS_GET(opts, prog_cnt, 0);
+ attr.query.prog_ids = ptr_to_u64(OPTS_GET(opts, prog_ids, NULL));
+ attr.query.attach_btf_id = OPTS_GET(opts, attach_btf_id, 0);
ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr));
- if (attach_flags)
- *attach_flags = attr.query.attach_flags;
- *prog_cnt = attr.query.prog_cnt;
+ if (OPTS_HAS(opts, prog_cnt))
+ opts->prog_cnt = attr.query.prog_cnt;
+ if (OPTS_HAS(opts, attach_flags))
+ opts->attach_flags = attr.query.attach_flags;
return libbpf_err_errno(ret);
}
+int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
+ __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
+{
+ LIBBPF_OPTS(bpf_prog_query_opts, p);
+ int ret;
+
+ p.query_flags = query_flags;
+ p.prog_ids = prog_ids;
+ p.prog_cnt = *prog_cnt;
+
+ ret = bpf_prog_query2(target_fd, type, &p);
+
+ if (attach_flags)
+ *attach_flags = p.attach_flags;
+ *prog_cnt = p.prog_cnt;
+
+ return ret;
+}
+
int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
void *data_out, __u32 *size_out, __u32 *retval,
__u32 *duration)
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index f4b4afb6d4ba..6b1ff77ac984 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -480,9 +480,24 @@ LIBBPF_API int bpf_map_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_link_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len);
+
+struct bpf_prog_query_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+ __u32 query_flags;
+ __u32 attach_flags; /* output argument */
+ __u32 *prog_ids;
+ __u32 prog_cnt; /* input+output argument */
+ __u32 attach_btf_id;
+};
+#define bpf_prog_query_opts__last_field attach_btf_id
+
+LIBBPF_API int bpf_prog_query2(int target_fd,
+ enum bpf_attach_type type,
+ struct bpf_prog_query_opts *opts);
LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,
__u32 query_flags, __u32 *attach_flags,
__u32 *prog_ids, __u32 *prog_cnt);
+
LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd);
LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
__u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index b5bc84039407..5e5bb3e437cc 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -450,4 +450,5 @@ LIBBPF_0.8.0 {
bpf_program__attach_usdt;
libbpf_register_prog_handler;
libbpf_unregister_prog_handler;
+ bpf_prog_query2;
} LIBBPF_0.7.0;
--
2.36.0.464.gb9c8b46e94-goog
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