From: Chenbo Feng
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
Acked-by: Alexei Starovoitov
---
include/linux/bpf.h | 6 ++--
include/uapi/linux/bpf.h | 6
kernel/bpf/arraymap.c| 6 +++-
kernel/bpf/devmap.c | 5 ++-
kernel/bpf/hashtab.c | 5 +--
kernel/bpf/inode.c | 15 ++---
kernel/bpf/lpm_trie.c| 3 +-
kernel/bpf/sockmap.c | 5 ++-
kernel/bpf/stackmap.c| 5 ++-
kernel/bpf/syscall.c | 80 +++-
10 files changed, 114 insertions(+), 22 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4373125de1f3..efbde1639970 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -308,11 +308,11 @@ 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);
@@ -331,6 +331,8 @@ 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
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6db9e1d679cd..9cb50a228c39 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -217,6 +217,10 @@ 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 */
@@ -259,6 +263,7 @@ 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 */
@@ -286,6 +291,7 @@ union bpf_attr {
__u32 map_id;
};
__u32 next_id;
+ __u32 open_flags;
};
struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 68d866628be0..988c04c91e10 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -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);
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index e093d9a2c4dd..e5d3de7cff2e 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -50,6 +50,9 @@
#include
#include
+#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);
diff --git a/kernel/bpf/hashtab.c
