korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-15 08:14:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

bpf: Add file mode configuration into bpf maps

Browse Source 
Introduce the map read/write flags to the eBPF syscalls that returns the
map fd. The flags is used to set up the file mode when construct a new
file descriptor for bpf maps. To not break the backward capability, the
f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise
it should be O_RDONLY or O_WRONLY. When the userspace want to modify or
read the map content, it will check the file mode to see if it is
allowed to make the change.

Signed-off-by: Chenbo Feng <fengc@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chenbo Feng 2017-10-18 13:00:22 -07:00 committed by David S. Miller
parent aec72f3392
commit 6e71b04a82
11 changed files with 122 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/bpf.h
View File

@ -315,11 +315,11 @@ void bpf_map_area_free(void *base);
extern int sysctl_unprivileged_bpf_disabled;
int bpf_map_new_fd(struct bpf_map *map);
int bpf_map_new_fd(struct bpf_map *map, int flags);
int bpf_prog_new_fd(struct bpf_prog *prog);
int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
int bpf_obj_get_user(const char __user *pathname);
int bpf_obj_get_user(const char __user *pathname, int flags);
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);
@ -338,6 +338,8 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
void *key, void *value, u64 map_flags);
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
int bpf_get_file_flag(int flags);
/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
* forced to use 'long' read/writes to try to atomically copy long counters.
* Best-effort only. No barriers here, since it _will_ race with concurrent
@ -421,7 +423,7 @@ static inline void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
{
}
static inline int bpf_obj_get_user(const char __user *pathname)
static inline int bpf_obj_get_user(const char __user *pathname, int flags)
{
return -EOPNOTSUPP;
}

6
include/uapi/linux/bpf.h
View File

@ -218,6 +218,10 @@ enum bpf_attach_type {
#define BPF_OBJ_NAME_LEN 16U
/* Flags for accessing BPF object */
#define BPF_F_RDONLY (1U << 3)
#define BPF_F_WRONLY (1U << 4)
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */
@ -260,6 +264,7 @@ union bpf_attr {
struct { /* anonymous struct used by BPF_OBJ_* commands */
__aligned_u64 pathname;
__u32 bpf_fd;
__u32 file_flags;
};
struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
@ -287,6 +292,7 @@ union bpf_attr {
__u32 map_id;
};
__u32 next_id;
__u32 open_flags;
};
struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */

6
kernel/bpf/arraymap.c
View File

@ -19,6 +19,9 @@
#include "map_in_map.h"
#define ARRAY_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
static void bpf_array_free_percpu(struct bpf_array *array)
{
int i;
@ -56,7 +59,8 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size == 0 || attr->map_flags & ~BPF_F_NUMA_NODE ||
attr->value_size == 0 ||
attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
(percpu && numa_node != NUMA_NO_NODE))
return ERR_PTR(-EINVAL);

5
kernel/bpf/devmap.c
View File

@ -50,6 +50,9 @@
#include <linux/bpf.h>
#include <linux/filter.h>
#define DEV_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
struct bpf_dtab_netdev {
struct net_device *dev;
struct bpf_dtab *dtab;
@ -80,7 +83,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size != 4 || attr->map_flags & ~BPF_F_NUMA_NODE)
attr->value_size != 4 || attr->map_flags & ~DEV_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
dtab = kzalloc(sizeof(*dtab), GFP_USER);

5
kernel/bpf/hashtab.c
View File

@ -18,8 +18,9 @@
#include "bpf_lru_list.h"
#include "map_in_map.h"
#define HTAB_CREATE_FLAG_MASK \
(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE)
#define HTAB_CREATE_FLAG_MASK \
(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
BPF_F_RDONLY | BPF_F_WRONLY)
struct bucket {
struct hlist_nulls_head head;

15
kernel/bpf/inode.c
View File

@ -295,7 +295,7 @@ out:
}
static void *bpf_obj_do_get(const struct filename *pathname,
enum bpf_type *type)
enum bpf_type *type, int flags)
{
struct inode *inode;
struct path path;
@ -307,7 +307,7 @@ static void *bpf_obj_do_get(const struct filename *pathname,
return ERR_PTR(ret);
inode = d_backing_inode(path.dentry);
ret = inode_permission(inode, MAY_WRITE);
ret = inode_permission(inode, ACC_MODE(flags));
if (ret)
goto out;
@ -326,18 +326,23 @@ out:
return ERR_PTR(ret);
}
int bpf_obj_get_user(const char __user *pathname)
int bpf_obj_get_user(const char __user *pathname, int flags)
{
enum bpf_type type = BPF_TYPE_UNSPEC;
struct filename *pname;
int ret = -ENOENT;
int f_flags;
void *raw;
f_flags = bpf_get_file_flag(flags);
if (f_flags < 0)
return f_flags;
pname = getname(pathname);
if (IS_ERR(pname))
return PTR_ERR(pname);
raw = bpf_obj_do_get(pname, &type);
raw = bpf_obj_do_get(pname, &type, f_flags);
if (IS_ERR(raw)) {
ret = PTR_ERR(raw);
goto out;
@ -346,7 +351,7 @@ int bpf_obj_get_user(const char __user *pathname)
if (type == BPF_TYPE_PROG)
ret = bpf_prog_new_fd(raw);
else if (type == BPF_TYPE_MAP)
ret = bpf_map_new_fd(raw);
ret = bpf_map_new_fd(raw, f_flags);
else
goto out;

3
kernel/bpf/lpm_trie.c
View File

@ -495,7 +495,8 @@ out:
#define LPM_KEY_SIZE_MAX LPM_KEY_SIZE(LPM_DATA_SIZE_MAX)
#define LPM_KEY_SIZE_MIN LPM_KEY_SIZE(LPM_DATA_SIZE_MIN)
#define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE)
#define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE | \
BPF_F_RDONLY | BPF_F_WRONLY)
static struct bpf_map *trie_alloc(union bpf_attr *attr)
{

5
kernel/bpf/sockmap.c
View File

@ -40,6 +40,9 @@
#include <linux/list.h>
#include <net/strparser.h>
#define SOCK_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
struct bpf_stab {
struct bpf_map map;
struct sock **sock_map;
@ -489,7 +492,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size != 4 || attr->map_flags & ~BPF_F_NUMA_NODE)
attr->value_size != 4 || attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
if (attr->value_size > KMALLOC_MAX_SIZE)

5
kernel/bpf/stackmap.c
View File

@ -11,6 +11,9 @@
#include <linux/perf_event.h>
#include "percpu_freelist.h"
#define STACK_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
struct stack_map_bucket {
struct pcpu_freelist_node fnode;
u32 hash;
@ -60,7 +63,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
if (attr->map_flags & ~BPF_F_NUMA_NODE)
if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
/* check sanity of attributes */

88
kernel/bpf/syscall.c
View File

@ -34,6 +34,8 @@
#define IS_FD_HASH(map) ((map)->map_type == BPF_MAP_TYPE_HASH_OF_MAPS)
#define IS_FD_MAP(map) (IS_FD_ARRAY(map) || IS_FD_HASH(map))
#define BPF_OBJ_FLAG_MASK (BPF_F_RDONLY | BPF_F_WRONLY)
DEFINE_PER_CPU(int, bpf_prog_active);
static DEFINE_IDR(prog_idr);
static DEFINE_SPINLOCK(prog_idr_lock);
@ -294,17 +296,48 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
}
#endif
static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz,
loff_t *ppos)
{
/* We need this handler such that alloc_file() enables
* f_mode with FMODE_CAN_READ.
*/
return -EINVAL;
}
static ssize_t bpf_dummy_write(struct file *filp, const char __user *buf,
size_t siz, loff_t *ppos)
{
/* We need this handler such that alloc_file() enables
* f_mode with FMODE_CAN_WRITE.
*/
return -EINVAL;
}
static const struct file_operations bpf_map_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = bpf_map_show_fdinfo,
#endif
.release = bpf_map_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
int bpf_map_new_fd(struct bpf_map *map)
int bpf_map_new_fd(struct bpf_map *map, int flags)
{
return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
O_RDWR | O_CLOEXEC);
flags | O_CLOEXEC);
}
int bpf_get_file_flag(int flags)
{
if ((flags & BPF_F_RDONLY) && (flags & BPF_F_WRONLY))
return -EINVAL;
if (flags & BPF_F_RDONLY)
return O_RDONLY;
if (flags & BPF_F_WRONLY)
return O_WRONLY;
return O_RDWR;
}
/* helper macro to check that unused fields 'union bpf_attr' are zero */
@ -344,12 +377,17 @@ static int map_create(union bpf_attr *attr)
{
int numa_node = bpf_map_attr_numa_node(attr);
struct bpf_map *map;
int f_flags;
int err;
err = CHECK_ATTR(BPF_MAP_CREATE);
if (err)
return -EINVAL;
f_flags = bpf_get_file_flag(attr->map_flags);
if (f_flags < 0)
return f_flags;
if (numa_node != NUMA_NO_NODE &&
((unsigned int)numa_node >= nr_node_ids ||
!node_online(numa_node)))
@ -375,7 +413,7 @@ static int map_create(union bpf_attr *attr)
if (err)
goto free_map;
err = bpf_map_new_fd(map);
err = bpf_map_new_fd(map, f_flags);
if (err < 0) {
/* failed to allocate fd.
* bpf_map_put() is needed because the above
@ -490,6 +528,11 @@ static int map_lookup_elem(union bpf_attr *attr)
if (IS_ERR(map))
return PTR_ERR(map);
if (!(f.file->f_mode & FMODE_CAN_READ)) {
err = -EPERM;
goto err_put;
}
key = memdup_user(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
@ -570,6 +613,11 @@ static int map_update_elem(union bpf_attr *attr)
if (IS_ERR(map))
return PTR_ERR(map);
if (!(f.file->f_mode & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
key = memdup_user(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
@ -659,6 +707,11 @@ static int map_delete_elem(union bpf_attr *attr)
if (IS_ERR(map))
return PTR_ERR(map);
if (!(f.file->f_mode & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
key = memdup_user(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
@ -702,6 +755,11 @@ static int map_get_next_key(union bpf_attr *attr)
if (IS_ERR(map))
return PTR_ERR(map);
if (!(f.file->f_mode & FMODE_CAN_READ)) {
err = -EPERM;
goto err_put;
}
if (ukey) {
key = memdup_user(ukey, map->key_size);
if (IS_ERR(key)) {
@ -908,6 +966,8 @@ static const struct file_operations bpf_prog_fops = {
.show_fdinfo = bpf_prog_show_fdinfo,
#endif
.release = bpf_prog_release,
.read = bpf_dummy_read,
.write = bpf_dummy_write,
};
int bpf_prog_new_fd(struct bpf_prog *prog)
@ -1117,11 +1177,11 @@ free_prog_nouncharge:
return err;
}
#define BPF_OBJ_LAST_FIELD bpf_fd
#define BPF_OBJ_LAST_FIELD file_flags
static int bpf_obj_pin(const union bpf_attr *attr)
{
if (CHECK_ATTR(BPF_OBJ))
if (CHECK_ATTR(BPF_OBJ) || attr->file_flags != 0)
return -EINVAL;
return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname));
@ -1129,10 +1189,12 @@ static int bpf_obj_pin(const union bpf_attr *attr)
static int bpf_obj_get(const union bpf_attr *attr)
{
if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0)
if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0 ||
attr->file_flags & ~BPF_OBJ_FLAG_MASK)
return -EINVAL;
return bpf_obj_get_user(u64_to_user_ptr(attr->pathname));
return bpf_obj_get_user(u64_to_user_ptr(attr->pathname),
attr->file_flags);
}
#ifdef CONFIG_CGROUP_BPF
@ -1392,20 +1454,26 @@ static int bpf_prog_get_fd_by_id(const union bpf_attr *attr)
return fd;
}
#define BPF_MAP_GET_FD_BY_ID_LAST_FIELD map_id
#define BPF_MAP_GET_FD_BY_ID_LAST_FIELD open_flags
static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
{
struct bpf_map *map;
u32 id = attr->map_id;
int f_flags;
int fd;
if (CHECK_ATTR(BPF_MAP_GET_FD_BY_ID))
if (CHECK_ATTR(BPF_MAP_GET_FD_BY_ID) ||
attr->open_flags & ~BPF_OBJ_FLAG_MASK)
return -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
f_flags = bpf_get_file_flag(attr->open_flags);
if (f_flags < 0)
return f_flags;
spin_lock_bh(&map_idr_lock);
map = idr_find(&map_idr, id);
if (map)
@ -1417,7 +1485,7 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
if (IS_ERR(map))
return PTR_ERR(map);
fd = bpf_map_new_fd(map);
fd = bpf_map_new_fd(map, f_flags);
if (fd < 0)
bpf_map_put(map);

2
net/netfilter/xt_bpf.c
View File

@ -56,7 +56,7 @@ static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
int retval, fd;
set_fs(KERNEL_DS);
fd = bpf_obj_get_user(path);
fd = bpf_obj_get_user(path, 0);
set_fs(oldfs);
if (fd < 0)
return fd;