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Message-ID: <20170927213756.1254938-2-kafai@fb.com>
Date: Wed, 27 Sep 2017 14:37:52 -0700
From: Martin KaFai Lau <kafai@...com>
To: <netdev@...r.kernel.org>
CC: Alexei Starovoitov <ast@...com>,
Daniel Borkmann <daniel@...earbox.net>, <kernel-team@...com>
Subject: [PATCH net-next 1/5] bpf: Add name, load_time, uid and map_ids to bpf_prog_info
The patch adds name and load_time to struct bpf_prog_aux. They
are also exported to bpf_prog_info.
The bpf_prog's name is passed by userspace during BPF_PROG_LOAD.
The kernel only stores the first (BPF_PROG_NAME_LEN - 1) bytes
and the name stored in the kernel is always \0 terminated.
The kernel will reject name that contains characters other than
isalnum() and '_'. It will also reject name that is not null
terminated.
The existing 'user->uid' of the bpf_prog_aux is also exported to
the bpf_prog_info as created_by_uid.
The existing 'used_maps' of the bpf_prog_aux is exported to
the newly added members 'nr_map_ids' and 'map_ids' of
the bpf_prog_info. On the input, nr_map_ids tells how
big the userspace's map_ids buffer is. On the output,
nr_map_ids tells the exact user_map_cnt and it will only
copy up to the userspace's map_ids buffer is allowed.
Signed-off-by: Martin KaFai Lau <kafai@...com>
Acked-by: Alexei Starovoitov <ast@...com>
Acked-by: Daniel Borkmann <daniel@...earbox.net>
---
include/linux/bpf.h | 2 ++
include/uapi/linux/bpf.h | 8 ++++++++
kernel/bpf/syscall.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2b672c50f160..33ccc474fb04 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -187,6 +187,8 @@ struct bpf_prog_aux {
struct bpf_map **used_maps;
struct bpf_prog *prog;
struct user_struct *user;
+ u64 load_time; /* ns since boottime */
+ u8 name[BPF_OBJ_NAME_LEN];
union {
struct work_struct work;
struct rcu_head rcu;
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e43491ac4823..bd6348269bf5 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -175,6 +175,8 @@ enum bpf_attach_type {
/* Specify numa node during map creation */
#define BPF_F_NUMA_NODE (1U << 2)
+#define BPF_OBJ_NAME_LEN 16U
+
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */
@@ -210,6 +212,7 @@ union bpf_attr {
__aligned_u64 log_buf; /* user supplied buffer */
__u32 kern_version; /* checked when prog_type=kprobe */
__u32 prog_flags;
+ __u8 prog_name[BPF_OBJ_NAME_LEN];
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -812,6 +815,11 @@ struct bpf_prog_info {
__u32 xlated_prog_len;
__aligned_u64 jited_prog_insns;
__aligned_u64 xlated_prog_insns;
+ __u64 load_time; /* ns since boottime */
+ __u32 created_by_uid;
+ __u32 nr_map_ids;
+ __aligned_u64 map_ids;
+ __u8 name[BPF_OBJ_NAME_LEN];
} __attribute__((aligned(8)));
struct bpf_map_info {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 25d074920a00..45970df3f820 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -23,6 +23,9 @@
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/idr.h>
+#include <linux/cred.h>
+#include <linux/timekeeping.h>
+#include <linux/ctype.h>
#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \
(map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
@@ -312,6 +315,30 @@ int bpf_map_new_fd(struct bpf_map *map)
offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
sizeof(attr->CMD##_LAST_FIELD)) != NULL
+/* dst and src must have at least BPF_OBJ_NAME_LEN number of bytes.
+ * Return 0 on success and < 0 on error.
+ */
+static int bpf_obj_name_cpy(char *dst, const char *src)
+{
+ const char *end = src + BPF_OBJ_NAME_LEN;
+
+ /* Copy all isalnum() and '_' char */
+ while (src < end && *src) {
+ if (!isalnum(*src) && *src != '_')
+ return -EINVAL;
+ *dst++ = *src++;
+ }
+
+ /* No '\0' found in BPF_OBJ_NAME_LEN number of bytes */
+ if (src == end)
+ return -EINVAL;
+
+ /* '\0' terminates dst */
+ *dst = 0;
+
+ return 0;
+}
+
#define BPF_MAP_CREATE_LAST_FIELD numa_node
/* called via syscall */
static int map_create(union bpf_attr *attr)
@@ -973,7 +1000,7 @@ struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
EXPORT_SYMBOL_GPL(bpf_prog_get_type);
/* last field in 'union bpf_attr' used by this command */
-#define BPF_PROG_LOAD_LAST_FIELD prog_flags
+#define BPF_PROG_LOAD_LAST_FIELD prog_name
static int bpf_prog_load(union bpf_attr *attr)
{
@@ -1037,6 +1064,11 @@ static int bpf_prog_load(union bpf_attr *attr)
if (err < 0)
goto free_prog;
+ prog->aux->load_time = ktime_get_boot_ns();
+ err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name);
+ if (err)
+ goto free_prog;
+
/* run eBPF verifier */
err = bpf_check(&prog, attr);
if (err < 0)
@@ -1358,8 +1390,25 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
info.type = prog->type;
info.id = prog->aux->id;
+ info.load_time = prog->aux->load_time;
+ info.created_by_uid = from_kuid_munged(current_user_ns(),
+ prog->aux->user->uid);
memcpy(info.tag, prog->tag, sizeof(prog->tag));
+ memcpy(info.name, prog->aux->name, sizeof(prog->aux->name));
+
+ ulen = info.nr_map_ids;
+ info.nr_map_ids = prog->aux->used_map_cnt;
+ ulen = min_t(u32, info.nr_map_ids, ulen);
+ if (ulen) {
+ u32 *user_map_ids = (u32 *)info.map_ids;
+ u32 i;
+
+ for (i = 0; i < ulen; i++)
+ if (put_user(prog->aux->used_maps[i]->id,
+ &user_map_ids[i]))
+ return -EFAULT;
+ }
if (!capable(CAP_SYS_ADMIN)) {
info.jited_prog_len = 0;
--
2.9.5
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