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Commit cb4d2b3f authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by David S. Miller
Browse files

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: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarAlexei Starovoitov <ast@fb.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cf5d74b8

include/linux/bpf.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -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 {

kernel/bpf/syscall.c

+50 −1
Original line number Diff line number Diff line
@@ -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;