diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/syscall.c | 66 |
1 files changed, 54 insertions, 12 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0c9276b54c88..b3ce516e5a20 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -355,6 +355,18 @@ static int bpf_map_release(struct inode *inode, struct file *filp) return 0; } +static fmode_t map_get_sys_perms(struct bpf_map *map, struct fd f) +{ + fmode_t mode = f.file->f_mode; + + /* Our file permissions may have been overridden by global + * map permissions facing syscall side. + */ + if (READ_ONCE(map->frozen)) + mode &= ~FMODE_CAN_WRITE; + return mode; +} + #ifdef CONFIG_PROC_FS static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp) { @@ -376,14 +388,16 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp) "max_entries:\t%u\n" "map_flags:\t%#x\n" "memlock:\t%llu\n" - "map_id:\t%u\n", + "map_id:\t%u\n" + "frozen:\t%u\n", map->map_type, map->key_size, map->value_size, map->max_entries, map->map_flags, map->pages * 1ULL << PAGE_SHIFT, - map->id); + map->id, + READ_ONCE(map->frozen)); if (owner_prog_type) { seq_printf(m, "owner_prog_type:\t%u\n", @@ -727,8 +741,7 @@ static int map_lookup_elem(union bpf_attr *attr) map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); - - if (!(f.file->f_mode & FMODE_CAN_READ)) { + if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) { err = -EPERM; goto err_put; } @@ -857,8 +870,7 @@ static int map_update_elem(union bpf_attr *attr) map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); - - if (!(f.file->f_mode & FMODE_CAN_WRITE)) { + if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) { err = -EPERM; goto err_put; } @@ -969,8 +981,7 @@ static int map_delete_elem(union bpf_attr *attr) map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); - - if (!(f.file->f_mode & FMODE_CAN_WRITE)) { + if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) { err = -EPERM; goto err_put; } @@ -1021,8 +1032,7 @@ static int map_get_next_key(union bpf_attr *attr) map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); - - if (!(f.file->f_mode & FMODE_CAN_READ)) { + if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) { err = -EPERM; goto err_put; } @@ -1089,8 +1099,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) map = __bpf_map_get(f); if (IS_ERR(map)) return PTR_ERR(map); - - if (!(f.file->f_mode & FMODE_CAN_WRITE)) { + if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) { err = -EPERM; goto err_put; } @@ -1132,6 +1141,36 @@ err_put: return err; } +#define BPF_MAP_FREEZE_LAST_FIELD map_fd + +static int map_freeze(const union bpf_attr *attr) +{ + int err = 0, ufd = attr->map_fd; + struct bpf_map *map; + struct fd f; + + if (CHECK_ATTR(BPF_MAP_FREEZE)) + return -EINVAL; + + f = fdget(ufd); + map = __bpf_map_get(f); + if (IS_ERR(map)) + return PTR_ERR(map); + if (READ_ONCE(map->frozen)) { + err = -EBUSY; + goto err_put; + } + if (!capable(CAP_SYS_ADMIN)) { + err = -EPERM; + goto err_put; + } + + WRITE_ONCE(map->frozen, true); +err_put: + fdput(f); + return err; +} + static const struct bpf_prog_ops * const bpf_prog_types[] = { #define BPF_PROG_TYPE(_id, _name) \ [_id] = & _name ## _prog_ops, @@ -2735,6 +2774,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_MAP_GET_NEXT_KEY: err = map_get_next_key(&attr); break; + case BPF_MAP_FREEZE: + err = map_freeze(&attr); + break; case BPF_PROG_LOAD: err = bpf_prog_load(&attr, uattr); break; |