mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Deepa Dinamani](/assets/img/avatar_default.png)
CURRENT_TIME macro is not appropriate for filesystems as it doesn't use the right granularity for filesystem timestamps. Use current_time() instead. CURRENT_TIME is also not y2038 safe. This is also in preparation for the patch that transitions vfs timestamps to use 64 bit time and hence make them y2038 safe. As part of the effort current_time() will be extended to do range checks. Hence, it is necessary for all file system timestamps to use current_time(). Also, current_time() will be transitioned along with vfs to be y2038 safe. Note that whenever a single call to current_time() is used to change timestamps in different inodes, it is because they share the same time granularity. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Felipe Balbi <balbi@kernel.org> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
384 lines
7.4 KiB
C
384 lines
7.4 KiB
C
/*
|
|
* Minimal file system backend for holding eBPF maps and programs,
|
|
* used by bpf(2) object pinning.
|
|
*
|
|
* Authors:
|
|
*
|
|
* Daniel Borkmann <daniel@iogearbox.net>
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* version 2 as published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/magic.h>
|
|
#include <linux/major.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/kdev_t.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/bpf.h>
|
|
|
|
enum bpf_type {
|
|
BPF_TYPE_UNSPEC = 0,
|
|
BPF_TYPE_PROG,
|
|
BPF_TYPE_MAP,
|
|
};
|
|
|
|
static void *bpf_any_get(void *raw, enum bpf_type type)
|
|
{
|
|
switch (type) {
|
|
case BPF_TYPE_PROG:
|
|
raw = bpf_prog_inc(raw);
|
|
break;
|
|
case BPF_TYPE_MAP:
|
|
raw = bpf_map_inc(raw, true);
|
|
break;
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
break;
|
|
}
|
|
|
|
return raw;
|
|
}
|
|
|
|
static void bpf_any_put(void *raw, enum bpf_type type)
|
|
{
|
|
switch (type) {
|
|
case BPF_TYPE_PROG:
|
|
bpf_prog_put(raw);
|
|
break;
|
|
case BPF_TYPE_MAP:
|
|
bpf_map_put_with_uref(raw);
|
|
break;
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
|
|
{
|
|
void *raw;
|
|
|
|
*type = BPF_TYPE_MAP;
|
|
raw = bpf_map_get_with_uref(ufd);
|
|
if (IS_ERR(raw)) {
|
|
*type = BPF_TYPE_PROG;
|
|
raw = bpf_prog_get(ufd);
|
|
}
|
|
|
|
return raw;
|
|
}
|
|
|
|
static const struct inode_operations bpf_dir_iops;
|
|
|
|
static const struct inode_operations bpf_prog_iops = { };
|
|
static const struct inode_operations bpf_map_iops = { };
|
|
|
|
static struct inode *bpf_get_inode(struct super_block *sb,
|
|
const struct inode *dir,
|
|
umode_t mode)
|
|
{
|
|
struct inode *inode;
|
|
|
|
switch (mode & S_IFMT) {
|
|
case S_IFDIR:
|
|
case S_IFREG:
|
|
break;
|
|
default:
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
inode = new_inode(sb);
|
|
if (!inode)
|
|
return ERR_PTR(-ENOSPC);
|
|
|
|
inode->i_ino = get_next_ino();
|
|
inode->i_atime = current_time(inode);
|
|
inode->i_mtime = inode->i_atime;
|
|
inode->i_ctime = inode->i_atime;
|
|
|
|
inode_init_owner(inode, dir, mode);
|
|
|
|
return inode;
|
|
}
|
|
|
|
static int bpf_inode_type(const struct inode *inode, enum bpf_type *type)
|
|
{
|
|
*type = BPF_TYPE_UNSPEC;
|
|
if (inode->i_op == &bpf_prog_iops)
|
|
*type = BPF_TYPE_PROG;
|
|
else if (inode->i_op == &bpf_map_iops)
|
|
*type = BPF_TYPE_MAP;
|
|
else
|
|
return -EACCES;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR);
|
|
if (IS_ERR(inode))
|
|
return PTR_ERR(inode);
|
|
|
|
inode->i_op = &bpf_dir_iops;
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
inc_nlink(inode);
|
|
inc_nlink(dir);
|
|
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,
|
|
umode_t mode, const struct inode_operations *iops)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);
|
|
if (IS_ERR(inode))
|
|
return PTR_ERR(inode);
|
|
|
|
inode->i_op = iops;
|
|
inode->i_private = dentry->d_fsdata;
|
|
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,
|
|
dev_t devt)
|
|
{
|
|
enum bpf_type type = MINOR(devt);
|
|
|
|
if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||
|
|
dentry->d_fsdata == NULL)
|
|
return -EPERM;
|
|
|
|
switch (type) {
|
|
case BPF_TYPE_PROG:
|
|
return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);
|
|
case BPF_TYPE_MAP:
|
|
return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);
|
|
default:
|
|
return -EPERM;
|
|
}
|
|
}
|
|
|
|
static struct dentry *
|
|
bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags)
|
|
{
|
|
if (strchr(dentry->d_name.name, '.'))
|
|
return ERR_PTR(-EPERM);
|
|
return simple_lookup(dir, dentry, flags);
|
|
}
|
|
|
|
static const struct inode_operations bpf_dir_iops = {
|
|
.lookup = bpf_lookup,
|
|
.mknod = bpf_mkobj,
|
|
.mkdir = bpf_mkdir,
|
|
.rmdir = simple_rmdir,
|
|
.rename = simple_rename,
|
|
.link = simple_link,
|
|
.unlink = simple_unlink,
|
|
};
|
|
|
|
static int bpf_obj_do_pin(const struct filename *pathname, void *raw,
|
|
enum bpf_type type)
|
|
{
|
|
struct dentry *dentry;
|
|
struct inode *dir;
|
|
struct path path;
|
|
umode_t mode;
|
|
dev_t devt;
|
|
int ret;
|
|
|
|
dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
|
|
if (IS_ERR(dentry))
|
|
return PTR_ERR(dentry);
|
|
|
|
mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());
|
|
devt = MKDEV(UNNAMED_MAJOR, type);
|
|
|
|
ret = security_path_mknod(&path, dentry, mode, devt);
|
|
if (ret)
|
|
goto out;
|
|
|
|
dir = d_inode(path.dentry);
|
|
if (dir->i_op != &bpf_dir_iops) {
|
|
ret = -EPERM;
|
|
goto out;
|
|
}
|
|
|
|
dentry->d_fsdata = raw;
|
|
ret = vfs_mknod(dir, dentry, mode, devt);
|
|
dentry->d_fsdata = NULL;
|
|
out:
|
|
done_path_create(&path, dentry);
|
|
return ret;
|
|
}
|
|
|
|
int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
|
|
{
|
|
struct filename *pname;
|
|
enum bpf_type type;
|
|
void *raw;
|
|
int ret;
|
|
|
|
pname = getname(pathname);
|
|
if (IS_ERR(pname))
|
|
return PTR_ERR(pname);
|
|
|
|
raw = bpf_fd_probe_obj(ufd, &type);
|
|
if (IS_ERR(raw)) {
|
|
ret = PTR_ERR(raw);
|
|
goto out;
|
|
}
|
|
|
|
ret = bpf_obj_do_pin(pname, raw, type);
|
|
if (ret != 0)
|
|
bpf_any_put(raw, type);
|
|
out:
|
|
putname(pname);
|
|
return ret;
|
|
}
|
|
|
|
static void *bpf_obj_do_get(const struct filename *pathname,
|
|
enum bpf_type *type)
|
|
{
|
|
struct inode *inode;
|
|
struct path path;
|
|
void *raw;
|
|
int ret;
|
|
|
|
ret = kern_path(pathname->name, LOOKUP_FOLLOW, &path);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
inode = d_backing_inode(path.dentry);
|
|
ret = inode_permission(inode, MAY_WRITE);
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = bpf_inode_type(inode, type);
|
|
if (ret)
|
|
goto out;
|
|
|
|
raw = bpf_any_get(inode->i_private, *type);
|
|
if (!IS_ERR(raw))
|
|
touch_atime(&path);
|
|
|
|
path_put(&path);
|
|
return raw;
|
|
out:
|
|
path_put(&path);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
int bpf_obj_get_user(const char __user *pathname)
|
|
{
|
|
enum bpf_type type = BPF_TYPE_UNSPEC;
|
|
struct filename *pname;
|
|
int ret = -ENOENT;
|
|
void *raw;
|
|
|
|
pname = getname(pathname);
|
|
if (IS_ERR(pname))
|
|
return PTR_ERR(pname);
|
|
|
|
raw = bpf_obj_do_get(pname, &type);
|
|
if (IS_ERR(raw)) {
|
|
ret = PTR_ERR(raw);
|
|
goto out;
|
|
}
|
|
|
|
if (type == BPF_TYPE_PROG)
|
|
ret = bpf_prog_new_fd(raw);
|
|
else if (type == BPF_TYPE_MAP)
|
|
ret = bpf_map_new_fd(raw);
|
|
else
|
|
goto out;
|
|
|
|
if (ret < 0)
|
|
bpf_any_put(raw, type);
|
|
out:
|
|
putname(pname);
|
|
return ret;
|
|
}
|
|
|
|
static void bpf_evict_inode(struct inode *inode)
|
|
{
|
|
enum bpf_type type;
|
|
|
|
truncate_inode_pages_final(&inode->i_data);
|
|
clear_inode(inode);
|
|
|
|
if (!bpf_inode_type(inode, &type))
|
|
bpf_any_put(inode->i_private, type);
|
|
}
|
|
|
|
static const struct super_operations bpf_super_ops = {
|
|
.statfs = simple_statfs,
|
|
.drop_inode = generic_delete_inode,
|
|
.evict_inode = bpf_evict_inode,
|
|
};
|
|
|
|
static int bpf_fill_super(struct super_block *sb, void *data, int silent)
|
|
{
|
|
static struct tree_descr bpf_rfiles[] = { { "" } };
|
|
struct inode *inode;
|
|
int ret;
|
|
|
|
ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles);
|
|
if (ret)
|
|
return ret;
|
|
|
|
sb->s_op = &bpf_super_ops;
|
|
|
|
inode = sb->s_root->d_inode;
|
|
inode->i_op = &bpf_dir_iops;
|
|
inode->i_mode &= ~S_IALLUGO;
|
|
inode->i_mode |= S_ISVTX | S_IRWXUGO;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct dentry *bpf_mount(struct file_system_type *type, int flags,
|
|
const char *dev_name, void *data)
|
|
{
|
|
return mount_nodev(type, flags, data, bpf_fill_super);
|
|
}
|
|
|
|
static struct file_system_type bpf_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "bpf",
|
|
.mount = bpf_mount,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
static int __init bpf_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = sysfs_create_mount_point(fs_kobj, "bpf");
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = register_filesystem(&bpf_fs_type);
|
|
if (ret)
|
|
sysfs_remove_mount_point(fs_kobj, "bpf");
|
|
|
|
return ret;
|
|
}
|
|
fs_initcall(bpf_init);
|