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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@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau 2017-09-27 14:37:52 -07:00 committed by David S. Miller
parent cf5d74b85e
commit cb4d2b3f03
3 changed files with 60 additions and 1 deletions
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2
include/linux/bpf.h
View File

@ -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;

8
include/uapi/linux/bpf.h
View File

@ -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 {

51
kernel/bpf/syscall.c
View File

@ -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;