linux/fs/omfs/inode.c
Christian Brauner 21cb47be6f
inode: make init and permission helpers idmapped mount aware
The inode_owner_or_capable() helper determines whether the caller is the
owner of the inode or is capable with respect to that inode. Allow it to
handle idmapped mounts. If the inode is accessed through an idmapped
mount it according to the mount's user namespace. Afterwards the checks
are identical to non-idmapped mounts. If the initial user namespace is
passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Similarly, allow the inode_init_owner() helper to handle idmapped
mounts. It initializes a new inode on idmapped mounts by mapping the
fsuid and fsgid of the caller from the mount's user namespace. If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:16 +01:00

627 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Optimized MPEG FS - inode and super operations.
* Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/cred.h>
#include <linux/parser.h>
#include <linux/buffer_head.h>
#include <linux/vmalloc.h>
#include <linux/writeback.h>
#include <linux/seq_file.h>
#include <linux/crc-itu-t.h>
#include "omfs.h"
MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
MODULE_LICENSE("GPL");
struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
if (block >= sbi->s_num_blocks)
return NULL;
return sb_bread(sb, clus_to_blk(sbi, block));
}
struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
{
struct inode *inode;
u64 new_block;
int err;
int len;
struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
inode = new_inode(dir->i_sb);
if (!inode)
return ERR_PTR(-ENOMEM);
err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
&new_block, &len);
if (err)
goto fail;
inode->i_ino = new_block;
inode_init_owner(&init_user_ns, inode, NULL, mode);
inode->i_mapping->a_ops = &omfs_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
switch (mode & S_IFMT) {
case S_IFDIR:
inode->i_op = &omfs_dir_inops;
inode->i_fop = &omfs_dir_operations;
inode->i_size = sbi->s_sys_blocksize;
inc_nlink(inode);
break;
case S_IFREG:
inode->i_op = &omfs_file_inops;
inode->i_fop = &omfs_file_operations;
inode->i_size = 0;
break;
}
insert_inode_hash(inode);
mark_inode_dirty(inode);
return inode;
fail:
make_bad_inode(inode);
iput(inode);
return ERR_PTR(err);
}
/*
* Update the header checksums for a dirty inode based on its contents.
* Caller is expected to hold the buffer head underlying oi and mark it
* dirty.
*/
static void omfs_update_checksums(struct omfs_inode *oi)
{
int xor, i, ofs = 0, count;
u16 crc = 0;
unsigned char *ptr = (unsigned char *) oi;
count = be32_to_cpu(oi->i_head.h_body_size);
ofs = sizeof(struct omfs_header);
crc = crc_itu_t(crc, ptr + ofs, count);
oi->i_head.h_crc = cpu_to_be16(crc);
xor = ptr[0];
for (i = 1; i < OMFS_XOR_COUNT; i++)
xor ^= ptr[i];
oi->i_head.h_check_xor = xor;
}
static int __omfs_write_inode(struct inode *inode, int wait)
{
struct omfs_inode *oi;
struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
struct buffer_head *bh, *bh2;
u64 ctime;
int i;
int ret = -EIO;
int sync_failed = 0;
/* get current inode since we may have written sibling ptrs etc. */
bh = omfs_bread(inode->i_sb, inode->i_ino);
if (!bh)
goto out;
oi = (struct omfs_inode *) bh->b_data;
oi->i_head.h_self = cpu_to_be64(inode->i_ino);
if (S_ISDIR(inode->i_mode))
oi->i_type = OMFS_DIR;
else if (S_ISREG(inode->i_mode))
oi->i_type = OMFS_FILE;
else {
printk(KERN_WARNING "omfs: unknown file type: %d\n",
inode->i_mode);
goto out_brelse;
}
oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
sizeof(struct omfs_header));
oi->i_head.h_version = 1;
oi->i_head.h_type = OMFS_INODE_NORMAL;
oi->i_head.h_magic = OMFS_IMAGIC;
oi->i_size = cpu_to_be64(inode->i_size);
ctime = inode->i_ctime.tv_sec * 1000LL +
((inode->i_ctime.tv_nsec + 999)/1000);
oi->i_ctime = cpu_to_be64(ctime);
omfs_update_checksums(oi);
mark_buffer_dirty(bh);
if (wait) {
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh))
sync_failed = 1;
}
/* if mirroring writes, copy to next fsblock */
for (i = 1; i < sbi->s_mirrors; i++) {
bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
if (!bh2)
goto out_brelse;
memcpy(bh2->b_data, bh->b_data, bh->b_size);
mark_buffer_dirty(bh2);
if (wait) {
sync_dirty_buffer(bh2);
if (buffer_req(bh2) && !buffer_uptodate(bh2))
sync_failed = 1;
}
brelse(bh2);
}
ret = (sync_failed) ? -EIO : 0;
out_brelse:
brelse(bh);
out:
return ret;
}
static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
}
int omfs_sync_inode(struct inode *inode)
{
return __omfs_write_inode(inode, 1);
}
/*
* called when an entry is deleted, need to clear the bits in the
* bitmaps.
*/
static void omfs_evict_inode(struct inode *inode)
{
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (inode->i_nlink)
return;
if (S_ISREG(inode->i_mode)) {
inode->i_size = 0;
omfs_shrink_inode(inode);
}
omfs_clear_range(inode->i_sb, inode->i_ino, 2);
}
struct inode *omfs_iget(struct super_block *sb, ino_t ino)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
struct omfs_inode *oi;
struct buffer_head *bh;
u64 ctime;
unsigned long nsecs;
struct inode *inode;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
bh = omfs_bread(inode->i_sb, ino);
if (!bh)
goto iget_failed;
oi = (struct omfs_inode *)bh->b_data;
/* check self */
if (ino != be64_to_cpu(oi->i_head.h_self))
goto fail_bh;
inode->i_uid = sbi->s_uid;
inode->i_gid = sbi->s_gid;
ctime = be64_to_cpu(oi->i_ctime);
nsecs = do_div(ctime, 1000) * 1000L;
inode->i_atime.tv_sec = ctime;
inode->i_mtime.tv_sec = ctime;
inode->i_ctime.tv_sec = ctime;
inode->i_atime.tv_nsec = nsecs;
inode->i_mtime.tv_nsec = nsecs;
inode->i_ctime.tv_nsec = nsecs;
inode->i_mapping->a_ops = &omfs_aops;
switch (oi->i_type) {
case OMFS_DIR:
inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
inode->i_op = &omfs_dir_inops;
inode->i_fop = &omfs_dir_operations;
inode->i_size = sbi->s_sys_blocksize;
inc_nlink(inode);
break;
case OMFS_FILE:
inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
inode->i_fop = &omfs_file_operations;
inode->i_size = be64_to_cpu(oi->i_size);
break;
}
brelse(bh);
unlock_new_inode(inode);
return inode;
fail_bh:
brelse(bh);
iget_failed:
iget_failed(inode);
return ERR_PTR(-EIO);
}
static void omfs_put_super(struct super_block *sb)
{
struct omfs_sb_info *sbi = OMFS_SB(sb);
kfree(sbi->s_imap);
kfree(sbi);
sb->s_fs_info = NULL;
}
static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *s = dentry->d_sb;
struct omfs_sb_info *sbi = OMFS_SB(s);
u64 id = huge_encode_dev(s->s_bdev->bd_dev);
buf->f_type = OMFS_MAGIC;
buf->f_bsize = sbi->s_blocksize;
buf->f_blocks = sbi->s_num_blocks;
buf->f_files = sbi->s_num_blocks;
buf->f_namelen = OMFS_NAMELEN;
buf->f_fsid = u64_to_fsid(id);
buf->f_bfree = buf->f_bavail = buf->f_ffree =
omfs_count_free(s);
return 0;
}
/*
* Display the mount options in /proc/mounts.
*/
static int omfs_show_options(struct seq_file *m, struct dentry *root)
{
struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
umode_t cur_umask = current_umask();
if (!uid_eq(sbi->s_uid, current_uid()))
seq_printf(m, ",uid=%u",
from_kuid_munged(&init_user_ns, sbi->s_uid));
if (!gid_eq(sbi->s_gid, current_gid()))
seq_printf(m, ",gid=%u",
from_kgid_munged(&init_user_ns, sbi->s_gid));
if (sbi->s_dmask == sbi->s_fmask) {
if (sbi->s_fmask != cur_umask)
seq_printf(m, ",umask=%o", sbi->s_fmask);
} else {
if (sbi->s_dmask != cur_umask)
seq_printf(m, ",dmask=%o", sbi->s_dmask);
if (sbi->s_fmask != cur_umask)
seq_printf(m, ",fmask=%o", sbi->s_fmask);
}
return 0;
}
static const struct super_operations omfs_sops = {
.write_inode = omfs_write_inode,
.evict_inode = omfs_evict_inode,
.put_super = omfs_put_super,
.statfs = omfs_statfs,
.show_options = omfs_show_options,
};
/*
* For Rio Karma, there is an on-disk free bitmap whose location is
* stored in the root block. For ReplayTV, there is no such free bitmap
* so we have to walk the tree. Both inodes and file data are allocated
* from the same map. This array can be big (300k) so we allocate
* in units of the blocksize.
*/
static int omfs_get_imap(struct super_block *sb)
{
unsigned int bitmap_size, array_size;
int count;
struct omfs_sb_info *sbi = OMFS_SB(sb);
struct buffer_head *bh;
unsigned long **ptr;
sector_t block;
bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
if (sbi->s_bitmap_ino == ~0ULL)
goto out;
sbi->s_imap_size = array_size;
sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
if (!sbi->s_imap)
goto nomem;
block = clus_to_blk(sbi, sbi->s_bitmap_ino);
if (block >= sbi->s_num_blocks)
goto nomem;
ptr = sbi->s_imap;
for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
bh = sb_bread(sb, block++);
if (!bh)
goto nomem_free;
*ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
if (!*ptr) {
brelse(bh);
goto nomem_free;
}
if (count < sb->s_blocksize)
memset((void *)*ptr + count, 0xff,
sb->s_blocksize - count);
brelse(bh);
ptr++;
}
out:
return 0;
nomem_free:
for (count = 0; count < array_size; count++)
kfree(sbi->s_imap[count]);
kfree(sbi->s_imap);
nomem:
sbi->s_imap = NULL;
sbi->s_imap_size = 0;
return -ENOMEM;
}
enum {
Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask, Opt_err
};
static const match_table_t tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_dmask, "dmask=%o"},
{Opt_fmask, "fmask=%o"},
{Opt_err, NULL},
};
static int parse_options(char *options, struct omfs_sb_info *sbi)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
return 0;
sbi->s_uid = make_kuid(current_user_ns(), option);
if (!uid_valid(sbi->s_uid))
return 0;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
sbi->s_gid = make_kgid(current_user_ns(), option);
if (!gid_valid(sbi->s_gid))
return 0;
break;
case Opt_umask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_fmask = sbi->s_dmask = option;
break;
case Opt_dmask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_dmask = option;
break;
case Opt_fmask:
if (match_octal(&args[0], &option))
return 0;
sbi->s_fmask = option;
break;
default:
return 0;
}
}
return 1;
}
static int omfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct buffer_head *bh, *bh2;
struct omfs_super_block *omfs_sb;
struct omfs_root_block *omfs_rb;
struct omfs_sb_info *sbi;
struct inode *root;
int ret = -EINVAL;
sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
sbi->s_uid = current_uid();
sbi->s_gid = current_gid();
sbi->s_dmask = sbi->s_fmask = current_umask();
if (!parse_options((char *) data, sbi))
goto end;
sb->s_maxbytes = 0xffffffff;
sb->s_time_gran = NSEC_PER_MSEC;
sb->s_time_min = 0;
sb->s_time_max = U64_MAX / MSEC_PER_SEC;
sb_set_blocksize(sb, 0x200);
bh = sb_bread(sb, 0);
if (!bh)
goto end;
omfs_sb = (struct omfs_super_block *)bh->b_data;
if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
if (!silent)
printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
omfs_sb->s_magic);
goto out_brelse_bh;
}
sb->s_magic = OMFS_MAGIC;
sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
mutex_init(&sbi->s_bitmap_lock);
if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
(unsigned long long)sbi->s_num_blocks);
goto out_brelse_bh;
}
if (sbi->s_sys_blocksize > PAGE_SIZE) {
printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
sbi->s_sys_blocksize);
goto out_brelse_bh;
}
if (sbi->s_blocksize < sbi->s_sys_blocksize ||
sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
printk(KERN_ERR "omfs: block size (%d) is out of range\n",
sbi->s_blocksize);
goto out_brelse_bh;
}
/*
* Use sys_blocksize as the fs block since it is smaller than a
* page while the fs blocksize can be larger.
*/
sb_set_blocksize(sb, sbi->s_sys_blocksize);
/*
* ...and the difference goes into a shift. sys_blocksize is always
* a power of two factor of blocksize.
*/
sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
get_bitmask_order(sbi->s_sys_blocksize);
bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
if (!bh2)
goto out_brelse_bh;
omfs_rb = (struct omfs_root_block *)bh2->b_data;
sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
printk(KERN_ERR "omfs: block count discrepancy between "
"super and root blocks (%llx, %llx)\n",
(unsigned long long)sbi->s_num_blocks,
(unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
goto out_brelse_bh2;
}
if (sbi->s_bitmap_ino != ~0ULL &&
sbi->s_bitmap_ino > sbi->s_num_blocks) {
printk(KERN_ERR "omfs: free space bitmap location is corrupt "
"(%llx, total blocks %llx)\n",
(unsigned long long) sbi->s_bitmap_ino,
(unsigned long long) sbi->s_num_blocks);
goto out_brelse_bh2;
}
if (sbi->s_clustersize < 1 ||
sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
printk(KERN_ERR "omfs: cluster size out of range (%d)",
sbi->s_clustersize);
goto out_brelse_bh2;
}
ret = omfs_get_imap(sb);
if (ret)
goto out_brelse_bh2;
sb->s_op = &omfs_sops;
root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto out_brelse_bh2;
}
sb->s_root = d_make_root(root);
if (!sb->s_root) {
ret = -ENOMEM;
goto out_brelse_bh2;
}
printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
ret = 0;
out_brelse_bh2:
brelse(bh2);
out_brelse_bh:
brelse(bh);
end:
if (ret)
kfree(sbi);
return ret;
}
static struct dentry *omfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, omfs_fill_super);
}
static struct file_system_type omfs_fs_type = {
.owner = THIS_MODULE,
.name = "omfs",
.mount = omfs_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("omfs");
static int __init init_omfs_fs(void)
{
return register_filesystem(&omfs_fs_type);
}
static void __exit exit_omfs_fs(void)
{
unregister_filesystem(&omfs_fs_type);
}
module_init(init_omfs_fs);
module_exit(exit_omfs_fs);