linux-stable/fs/befs/linuxvfs.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/befs/linuxvfs.c
*
* Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/nls.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <linux/parser.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/exportfs.h>
#include <linux/seq_file.h>
#include "befs.h"
#include "btree.h"
#include "inode.h"
#include "datastream.h"
#include "super.h"
#include "io.h"
MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
MODULE_AUTHOR("Will Dyson");
MODULE_LICENSE("GPL");
/* The units the vfs expects inode->i_blocks to be in */
#define VFS_BLOCK_SIZE 512
static int befs_readdir(struct file *, struct dir_context *);
static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
static int befs_readpage(struct file *file, struct page *page);
static sector_t befs_bmap(struct address_space *mapping, sector_t block);
static struct dentry *befs_lookup(struct inode *, struct dentry *,
unsigned int);
static struct inode *befs_iget(struct super_block *, unsigned long);
static struct inode *befs_alloc_inode(struct super_block *sb);
static void befs_free_inode(struct inode *inode);
static void befs_destroy_inodecache(void);
static int befs_symlink_readpage(struct file *, struct page *);
static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
char **out, int *out_len);
static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
char **out, int *out_len);
static void befs_put_super(struct super_block *);
static int befs_remount(struct super_block *, int *, char *);
static int befs_statfs(struct dentry *, struct kstatfs *);
static int befs_show_options(struct seq_file *, struct dentry *);
static int parse_options(char *, struct befs_mount_options *);
static struct dentry *befs_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type);
static struct dentry *befs_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type);
static struct dentry *befs_get_parent(struct dentry *child);
static const struct super_operations befs_sops = {
.alloc_inode = befs_alloc_inode, /* allocate a new inode */
.free_inode = befs_free_inode, /* deallocate an inode */
.put_super = befs_put_super, /* uninit super */
.statfs = befs_statfs, /* statfs */
.remount_fs = befs_remount,
.show_options = befs_show_options,
};
/* slab cache for befs_inode_info objects */
static struct kmem_cache *befs_inode_cachep;
static const struct file_operations befs_dir_operations = {
.read = generic_read_dir,
.iterate_shared = befs_readdir,
.llseek = generic_file_llseek,
};
static const struct inode_operations befs_dir_inode_operations = {
.lookup = befs_lookup,
};
static const struct address_space_operations befs_aops = {
.readpage = befs_readpage,
.bmap = befs_bmap,
};
static const struct address_space_operations befs_symlink_aops = {
.readpage = befs_symlink_readpage,
};
static const struct export_operations befs_export_operations = {
.fh_to_dentry = befs_fh_to_dentry,
.fh_to_parent = befs_fh_to_parent,
.get_parent = befs_get_parent,
};
/*
* Called by generic_file_read() to read a page of data
*
* In turn, simply calls a generic block read function and
* passes it the address of befs_get_block, for mapping file
* positions to disk blocks.
*/
static int
befs_readpage(struct file *file, struct page *page)
{
return block_read_full_page(page, befs_get_block);
}
static sector_t
befs_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping, block, befs_get_block);
}
/*
* Generic function to map a file position (block) to a
* disk offset (passed back in bh_result).
*
* Used by many higher level functions.
*
* Calls befs_fblock2brun() in datastream.c to do the real work.
*/
static int
befs_get_block(struct inode *inode, sector_t block,
struct buffer_head *bh_result, int create)
{
struct super_block *sb = inode->i_sb;
befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
befs_block_run run = BAD_IADDR;
int res;
ulong disk_off;
befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
(unsigned long)inode->i_ino, (long)block);
if (create) {
befs_error(sb, "befs_get_block() was asked to write to "
"block %ld in inode %lu", (long)block,
(unsigned long)inode->i_ino);
return -EPERM;
}
res = befs_fblock2brun(sb, ds, block, &run);
if (res != BEFS_OK) {
befs_error(sb,
"<--- %s for inode %lu, block %ld ERROR",
__func__, (unsigned long)inode->i_ino,
(long)block);
return -EFBIG;
}
disk_off = (ulong) iaddr2blockno(sb, &run);
map_bh(bh_result, inode->i_sb, disk_off);
befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
__func__, (unsigned long)inode->i_ino, (long)block,
(unsigned long)disk_off);
return 0;
}
static struct dentry *
befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
struct inode *inode;
struct super_block *sb = dir->i_sb;
const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
befs_off_t offset;
int ret;
int utfnamelen;
char *utfname;
const char *name = dentry->d_name.name;
befs_debug(sb, "---> %s name %pd inode %ld", __func__,
dentry, dir->i_ino);
/* Convert to UTF-8 */
if (BEFS_SB(sb)->nls) {
ret =
befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
if (ret < 0) {
befs_debug(sb, "<--- %s ERROR", __func__);
return ERR_PTR(ret);
}
ret = befs_btree_find(sb, ds, utfname, &offset);
kfree(utfname);
} else {
ret = befs_btree_find(sb, ds, name, &offset);
}
if (ret == BEFS_BT_NOT_FOUND) {
befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
inode = NULL;
} else if (ret != BEFS_OK || offset == 0) {
befs_error(sb, "<--- %s Error", __func__);
inode = ERR_PTR(-ENODATA);
} else {
inode = befs_iget(dir->i_sb, (ino_t) offset);
}
befs_debug(sb, "<--- %s", __func__);
return d_splice_alias(inode, dentry);
}
static int
befs_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
befs_off_t value;
int result;
size_t keysize;
char keybuf[BEFS_NAME_LEN + 1];
befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
__func__, file, inode->i_ino, ctx->pos);
while (1) {
result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
keybuf, &keysize, &value);
if (result == BEFS_ERR) {
befs_debug(sb, "<--- %s ERROR", __func__);
befs_error(sb, "IO error reading %pD (inode %lu)",
file, inode->i_ino);
return -EIO;
} else if (result == BEFS_BT_END) {
befs_debug(sb, "<--- %s END", __func__);
return 0;
} else if (result == BEFS_BT_EMPTY) {
befs_debug(sb, "<--- %s Empty directory", __func__);
return 0;
}
/* Convert to NLS */
if (BEFS_SB(sb)->nls) {
char *nlsname;
int nlsnamelen;
result =
befs_utf2nls(sb, keybuf, keysize, &nlsname,
&nlsnamelen);
if (result < 0) {
befs_debug(sb, "<--- %s ERROR", __func__);
return result;
}
if (!dir_emit(ctx, nlsname, nlsnamelen,
(ino_t) value, DT_UNKNOWN)) {
kfree(nlsname);
return 0;
}
kfree(nlsname);
} else {
if (!dir_emit(ctx, keybuf, keysize,
(ino_t) value, DT_UNKNOWN))
return 0;
}
ctx->pos++;
}
}
static struct inode *
befs_alloc_inode(struct super_block *sb)
{
struct befs_inode_info *bi;
bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
if (!bi)
return NULL;
return &bi->vfs_inode;
}
static void befs_free_inode(struct inode *inode)
{
kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
}
static void init_once(void *foo)
{
struct befs_inode_info *bi = (struct befs_inode_info *) foo;
inode_init_once(&bi->vfs_inode);
}
static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
{
struct buffer_head *bh;
befs_inode *raw_inode;
struct befs_sb_info *befs_sb = BEFS_SB(sb);
struct befs_inode_info *befs_ino;
struct inode *inode;
befs_debug(sb, "---> %s inode = %lu", __func__, ino);
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
befs_ino = BEFS_I(inode);
/* convert from vfs's inode number to befs's inode number */
befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
befs_debug(sb, " real inode number [%u, %hu, %hu]",
befs_ino->i_inode_num.allocation_group,
befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
bh = sb_bread(sb, inode->i_ino);
if (!bh) {
befs_error(sb, "unable to read inode block - "
"inode = %lu", inode->i_ino);
goto unacquire_none;
}
raw_inode = (befs_inode *) bh->b_data;
befs_dump_inode(sb, raw_inode);
if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
befs_error(sb, "Bad inode: %lu", inode->i_ino);
goto unacquire_bh;
}
inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
/*
* set uid and gid. But since current BeOS is single user OS, so
* you can change by "uid" or "gid" options.
*/
inode->i_uid = befs_sb->mount_opts.use_uid ?
befs_sb->mount_opts.uid :
make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
inode->i_gid = befs_sb->mount_opts.use_gid ?
befs_sb->mount_opts.gid :
make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
set_nlink(inode, 1);
/*
* BEFS's time is 64 bits, but current VFS is 32 bits...
* BEFS don't have access time. Nor inode change time. VFS
* doesn't have creation time.
* Also, the lower 16 bits of the last_modified_time and
* create_time are just a counter to help ensure uniqueness
* for indexing purposes. (PFD, page 54)
*/
inode->i_mtime.tv_sec =
fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
inode->i_mtime.tv_nsec = 0; /* lower 16 bits are not a time */
inode->i_ctime = inode->i_mtime;
inode->i_atime = inode->i_mtime;
befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
inode->i_size = 0;
inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
BEFS_SYMLINK_LEN);
} else {
int num_blks;
befs_ino->i_data.ds =
fsds_to_cpu(sb, &raw_inode->data.datastream);
num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
inode->i_blocks =
num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
inode->i_size = befs_ino->i_data.ds.size;
}
inode->i_mapping->a_ops = &befs_aops;
if (S_ISREG(inode->i_mode)) {
inode->i_fop = &generic_ro_fops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &befs_dir_inode_operations;
inode->i_fop = &befs_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
inode->i_op = &page_symlink_inode_operations;
inode_nohighmem(inode);
inode->i_mapping->a_ops = &befs_symlink_aops;
} else {
inode->i_link = befs_ino->i_data.symlink;
inode->i_op = &simple_symlink_inode_operations;
}
} else {
befs_error(sb, "Inode %lu is not a regular file, "
"directory or symlink. THAT IS WRONG! BeFS has no "
"on disk special files", inode->i_ino);
goto unacquire_bh;
}
brelse(bh);
befs_debug(sb, "<--- %s", __func__);
unlock_new_inode(inode);
return inode;
unacquire_bh:
brelse(bh);
unacquire_none:
iget_failed(inode);
befs_debug(sb, "<--- %s - Bad inode", __func__);
return ERR_PTR(-EIO);
}
/* Initialize the inode cache. Called at fs setup.
*
* Taken from NFS implementation by Al Viro.
*/
static int __init
befs_init_inodecache(void)
{
befs: Define usercopy region in befs_inode_cache slab cache befs symlink pathnames, stored in struct befs_inode_info.i_data.symlink and therefore contained in the befs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/befs/linuxvfs.c: befs_alloc_inode(...): ... bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL); ... return &bi->vfs_inode; befs_iget(...): ... strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink, BEFS_SYMLINK_LEN); ... inode->i_link = befs_ino->i_data.symlink; example usage trace: readlink_copy+0x43/0x70 vfs_readlink+0x62/0x110 SyS_readlinkat+0x100/0x130 fs/namei.c: readlink_copy(..., link): ... copy_to_user(..., link, len); (inlined in vfs_readlink) generic_readlink(dentry, ...): struct inode *inode = d_inode(dentry); const char *link = inode->i_link; ... readlink_copy(..., link); In support of usercopy hardening, this patch defines a region in the befs_inode_cache slab cache in which userspace copy operations are allowed. This region is known as the slab cache's usercopy region. Slab caches can now check that each dynamically sized copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor <dave@nullcore.net> [kees: adjust commit log, provide usage trace] Cc: Luis de Bethencourt <luisbg@kernel.org> Cc: Salah Triki <salah.triki@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Luis de Bethencourt <luisbg@kernel.org>
2017-06-11 02:50:32 +00:00
befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
sizeof(struct befs_inode_info), 0,
(SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
SLAB_ACCOUNT),
offsetof(struct befs_inode_info,
i_data.symlink),
sizeof_field(struct befs_inode_info,
i_data.symlink),
init_once);
if (befs_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
/* Called at fs teardown.
*
* Taken from NFS implementation by Al Viro.
*/
static void
befs_destroy_inodecache(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(befs_inode_cachep);
}
/*
* The inode of symbolic link is different to data stream.
* The data stream become link name. Unless the LONG_SYMLINK
* flag is set.
*/
static int befs_symlink_readpage(struct file *unused, struct page *page)
{
struct inode *inode = page->mapping->host;
struct super_block *sb = inode->i_sb;
struct befs_inode_info *befs_ino = BEFS_I(inode);
befs_data_stream *data = &befs_ino->i_data.ds;
befs_off_t len = data->size;
char *link = page_address(page);
if (len == 0 || len > PAGE_SIZE) {
befs_error(sb, "Long symlink with illegal length");
goto fail;
}
befs_debug(sb, "Follow long symlink");
if (befs_read_lsymlink(sb, data, link, len) != len) {
befs_error(sb, "Failed to read entire long symlink");
goto fail;
}
link[len - 1] = '\0';
SetPageUptodate(page);
unlock_page(page);
return 0;
fail:
SetPageError(page);
unlock_page(page);
return -EIO;
}
/*
* UTF-8 to NLS charset convert routine
*
* Uses uni2char() / char2uni() rather than the nls tables directly
*/
static int
befs_utf2nls(struct super_block *sb, const char *in,
int in_len, char **out, int *out_len)
{
struct nls_table *nls = BEFS_SB(sb)->nls;
int i, o;
unicode_t uni;
int unilen, utflen;
char *result;
/* The utf8->nls conversion won't make the final nls string bigger
* than the utf one, but if the string is pure ascii they'll have the
* same width and an extra char is needed to save the additional \0
*/
int maxlen = in_len + 1;
befs_debug(sb, "---> %s", __func__);
if (!nls) {
befs_error(sb, "%s called with no NLS table loaded", __func__);
return -EINVAL;
}
*out = result = kmalloc(maxlen, GFP_NOFS);
if (!*out)
return -ENOMEM;
for (i = o = 0; i < in_len; i += utflen, o += unilen) {
/* convert from UTF-8 to Unicode */
utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
if (utflen < 0)
goto conv_err;
/* convert from Unicode to nls */
if (uni > MAX_WCHAR_T)
goto conv_err;
unilen = nls->uni2char(uni, &result[o], in_len - o);
if (unilen < 0)
goto conv_err;
}
result[o] = '\0';
*out_len = o;
befs_debug(sb, "<--- %s", __func__);
return o;
conv_err:
befs_error(sb, "Name using character set %s contains a character that "
"cannot be converted to unicode.", nls->charset);
befs_debug(sb, "<--- %s", __func__);
kfree(result);
return -EILSEQ;
}
/**
* befs_nls2utf - Convert NLS string to utf8 encodeing
* @sb: Superblock
* @in: Input string buffer in NLS format
* @in_len: Length of input string in bytes
* @out: The output string in UTF-8 format
* @out_len: Length of the output buffer
*
* Converts input string @in, which is in the format of the loaded NLS map,
* into a utf8 string.
*
* The destination string @out is allocated by this function and the caller is
* responsible for freeing it with kfree()
*
* On return, *@out_len is the length of @out in bytes.
*
* On success, the return value is the number of utf8 characters written to
* the output buffer @out.
*
* On Failure, a negative number coresponding to the error code is returned.
*/
static int
befs_nls2utf(struct super_block *sb, const char *in,
int in_len, char **out, int *out_len)
{
struct nls_table *nls = BEFS_SB(sb)->nls;
int i, o;
wchar_t uni;
int unilen, utflen;
char *result;
/*
* There are nls characters that will translate to 3-chars-wide UTF-8
* characters, an additional byte is needed to save the final \0
* in special cases
*/
int maxlen = (3 * in_len) + 1;
befs_debug(sb, "---> %s\n", __func__);
if (!nls) {
befs_error(sb, "%s called with no NLS table loaded.",
__func__);
return -EINVAL;
}
*out = result = kmalloc(maxlen, GFP_NOFS);
if (!*out) {
*out_len = 0;
return -ENOMEM;
}
for (i = o = 0; i < in_len; i += unilen, o += utflen) {
/* convert from nls to unicode */
unilen = nls->char2uni(&in[i], in_len - i, &uni);
if (unilen < 0)
goto conv_err;
/* convert from unicode to UTF-8 */
utflen = utf32_to_utf8(uni, &result[o], 3);
if (utflen <= 0)
goto conv_err;
}
result[o] = '\0';
*out_len = o;
befs_debug(sb, "<--- %s", __func__);
return i;
conv_err:
befs_error(sb, "Name using character set %s contains a character that "
"cannot be converted to unicode.", nls->charset);
befs_debug(sb, "<--- %s", __func__);
kfree(result);
return -EILSEQ;
}
static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
uint32_t generation)
{
/* No need to handle i_generation */
return befs_iget(sb, ino);
}
/*
* Map a NFS file handle to a corresponding dentry
*/
static struct dentry *befs_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
befs_nfs_get_inode);
}
/*
* Find the parent for a file specified by NFS handle
*/
static struct dentry *befs_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
befs_nfs_get_inode);
}
static struct dentry *befs_get_parent(struct dentry *child)
{
struct inode *parent;
struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));
parent = befs_iget(child->d_sb,
(unsigned long)befs_ino->i_parent.start);
if (IS_ERR(parent))
return ERR_CAST(parent);
return d_obtain_alias(parent);
}
enum {
Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
};
static const match_table_t befs_tokens = {
{Opt_uid, "uid=%d"},
{Opt_gid, "gid=%d"},
{Opt_charset, "iocharset=%s"},
{Opt_debug, "debug"},
{Opt_err, NULL}
};
static int
parse_options(char *options, struct befs_mount_options *opts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
kuid_t uid;
kgid_t gid;
/* Initialize options */
opts->uid = GLOBAL_ROOT_UID;
opts->gid = GLOBAL_ROOT_GID;
opts->use_uid = 0;
opts->use_gid = 0;
opts->iocharset = NULL;
opts->debug = 0;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, befs_tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
return 0;
uid = INVALID_UID;
if (option >= 0)
uid = make_kuid(current_user_ns(), option);
if (!uid_valid(uid)) {
pr_err("Invalid uid %d, "
"using default\n", option);
break;
}
opts->uid = uid;
opts->use_uid = 1;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
gid = INVALID_GID;
if (option >= 0)
gid = make_kgid(current_user_ns(), option);
if (!gid_valid(gid)) {
pr_err("Invalid gid %d, "
"using default\n", option);
break;
}
opts->gid = gid;
opts->use_gid = 1;
break;
case Opt_charset:
kfree(opts->iocharset);
opts->iocharset = match_strdup(&args[0]);
if (!opts->iocharset) {
pr_err("allocation failure for "
"iocharset string\n");
return 0;
}
break;
case Opt_debug:
opts->debug = 1;
break;
default:
pr_err("Unrecognized mount option \"%s\" "
"or missing value\n", p);
return 0;
}
}
return 1;
}
static int befs_show_options(struct seq_file *m, struct dentry *root)
{
struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
struct befs_mount_options *opts = &befs_sb->mount_opts;
if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
seq_printf(m, ",uid=%u",
from_kuid_munged(&init_user_ns, opts->uid));
if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
seq_printf(m, ",gid=%u",
from_kgid_munged(&init_user_ns, opts->gid));
if (opts->iocharset)
seq_printf(m, ",charset=%s", opts->iocharset);
if (opts->debug)
seq_puts(m, ",debug");
return 0;
}
/* This function has the responsibiltiy of getting the
* filesystem ready for unmounting.
* Basically, we free everything that we allocated in
* befs_read_inode
*/
static void
befs_put_super(struct super_block *sb)
{
kfree(BEFS_SB(sb)->mount_opts.iocharset);
BEFS_SB(sb)->mount_opts.iocharset = NULL;
unload_nls(BEFS_SB(sb)->nls);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
}
/* Allocate private field of the superblock, fill it.
*
* Finish filling the public superblock fields
* Make the root directory
* Load a set of NLS translations if needed.
*/
static int
befs_fill_super(struct super_block *sb, void *data, int silent)
{
struct buffer_head *bh;
struct befs_sb_info *befs_sb;
befs_super_block *disk_sb;
struct inode *root;
long ret = -EINVAL;
const unsigned long sb_block = 0;
const off_t x86_sb_off = 512;
int blocksize;
sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
if (sb->s_fs_info == NULL)
goto unacquire_none;
befs_sb = BEFS_SB(sb);
if (!parse_options((char *) data, &befs_sb->mount_opts)) {
if (!silent)
befs_error(sb, "cannot parse mount options");
goto unacquire_priv_sbp;
}
befs_debug(sb, "---> %s", __func__);
if (!sb_rdonly(sb)) {
befs_warning(sb,
"No write support. Marking filesystem read-only");
Rename superblock flags (MS_xyz -> SB_xyz) This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27 21:05:09 +00:00
sb->s_flags |= SB_RDONLY;
}
/*
* Set dummy blocksize to read super block.
* Will be set to real fs blocksize later.
*
* Linux 2.4.10 and later refuse to read blocks smaller than
* the logical block size for the device. But we also need to read at
* least 1k to get the second 512 bytes of the volume.
*/
blocksize = sb_min_blocksize(sb, 1024);
if (!blocksize) {
if (!silent)
befs_error(sb, "unable to set blocksize");
goto unacquire_priv_sbp;
}
bh = sb_bread(sb, sb_block);
if (!bh) {
if (!silent)
befs_error(sb, "unable to read superblock");
goto unacquire_priv_sbp;
}
/* account for offset of super block on x86 */
disk_sb = (befs_super_block *) bh->b_data;
befs: annotate fs32 on tests for superblock endianness Does compile-time byteswapping rather than runtime. Noticed by sparse: fs/befs/super.c:29:6: warning: cast to restricted __le32 fs/befs/super.c:29:6: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/super.c:31:11: warning: cast to restricted __be32 fs/befs/super.c:31:11: warning: cast from restricted fs32 fs/befs/linuxvfs.c:811:7: warning: cast to restricted __le32 fs/befs/linuxvfs.c:811:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 fs/befs/linuxvfs.c:812:7: warning: cast to restricted __be32 fs/befs/linuxvfs.c:812:7: warning: cast from restricted fs32 Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: "Sergey S. Kostyliov" <rathamahata@php4.ru> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 05:04:03 +00:00
if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
(disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
befs_debug(sb, "Using PPC superblock location");
} else {
befs_debug(sb, "Using x86 superblock location");
disk_sb =
(befs_super_block *) ((void *) bh->b_data + x86_sb_off);
}
if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
(befs_check_sb(sb) != BEFS_OK))
goto unacquire_bh;
befs_dump_super_block(sb, disk_sb);
brelse(bh);
if (befs_sb->num_blocks > ~((sector_t)0)) {
if (!silent)
befs_error(sb, "blocks count: %llu is larger than the host can use",
befs_sb->num_blocks);
goto unacquire_priv_sbp;
}
/*
* set up enough so that it can read an inode
* Fill in kernel superblock fields from private sb
*/
sb->s_magic = BEFS_SUPER_MAGIC;
/* Set real blocksize of fs */
sb_set_blocksize(sb, (ulong) befs_sb->block_size);
sb->s_op = &befs_sops;
sb->s_export_op = &befs_export_operations;
root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto unacquire_priv_sbp;
}
sb->s_root = d_make_root(root);
if (!sb->s_root) {
if (!silent)
befs_error(sb, "get root inode failed");
goto unacquire_priv_sbp;
}
/* load nls library */
if (befs_sb->mount_opts.iocharset) {
befs_debug(sb, "Loading nls: %s",
befs_sb->mount_opts.iocharset);
befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
if (!befs_sb->nls) {
befs_warning(sb, "Cannot load nls %s"
" loading default nls",
befs_sb->mount_opts.iocharset);
befs_sb->nls = load_nls_default();
}
/* load default nls if none is specified in mount options */
} else {
befs_debug(sb, "Loading default nls");
befs_sb->nls = load_nls_default();
}
return 0;
unacquire_bh:
brelse(bh);
unacquire_priv_sbp:
kfree(befs_sb->mount_opts.iocharset);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
unacquire_none:
return ret;
}
static int
befs_remount(struct super_block *sb, int *flags, char *data)
{
fs: push sync_filesystem() down to the file system's remount_fs() Previously, the no-op "mount -o mount /dev/xxx" operation when the file system is already mounted read-write causes an implied, unconditional syncfs(). This seems pretty stupid, and it's certainly documented or guaraunteed to do this, nor is it particularly useful, except in the case where the file system was mounted rw and is getting remounted read-only. However, it's possible that there might be some file systems that are actually depending on this behavior. In most file systems, it's probably fine to only call sync_filesystem() when transitioning from read-write to read-only, and there are some file systems where this is not needed at all (for example, for a pseudo-filesystem or something like romfs). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Evgeniy Dushistov <dushistov@mail.ru> Cc: Jan Kara <jack@suse.cz> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Anders Larsen <al@alarsen.net> Cc: Phillip Lougher <phillip@squashfs.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: xfs@oss.sgi.com Cc: linux-btrfs@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: codalist@coda.cs.cmu.edu Cc: linux-ext4@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: fuse-devel@lists.sourceforge.net Cc: cluster-devel@redhat.com Cc: linux-mtd@lists.infradead.org Cc: jfs-discussion@lists.sourceforge.net Cc: linux-nfs@vger.kernel.org Cc: linux-nilfs@vger.kernel.org Cc: linux-ntfs-dev@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Cc: reiserfs-devel@vger.kernel.org
2014-03-13 14:14:33 +00:00
sync_filesystem(sb);
Rename superblock flags (MS_xyz -> SB_xyz) This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27 21:05:09 +00:00
if (!(*flags & SB_RDONLY))
return -EINVAL;
return 0;
}
static int
befs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
befs_debug(sb, "---> %s", __func__);
buf->f_type = BEFS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = BEFS_SB(sb)->num_blocks;
buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
buf->f_bavail = buf->f_bfree;
buf->f_files = 0; /* UNKNOWN */
buf->f_ffree = 0; /* UNKNOWN */
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
buf->f_namelen = BEFS_NAME_LEN;
befs_debug(sb, "<--- %s", __func__);
return 0;
}
static struct dentry *
befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
}
static struct file_system_type befs_fs_type = {
.owner = THIS_MODULE,
.name = "befs",
.mount = befs_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
fs: Limit sys_mount to only request filesystem modules. Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Kees Cook <keescook@chromium.org> Reported-by: Kees Cook <keescook@google.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-03 03:39:14 +00:00
MODULE_ALIAS_FS("befs");
static int __init
init_befs_fs(void)
{
int err;
pr_info("version: %s\n", BEFS_VERSION);
err = befs_init_inodecache();
if (err)
goto unacquire_none;
err = register_filesystem(&befs_fs_type);
if (err)
goto unacquire_inodecache;
return 0;
unacquire_inodecache:
befs_destroy_inodecache();
unacquire_none:
return err;
}
static void __exit
exit_befs_fs(void)
{
befs_destroy_inodecache();
unregister_filesystem(&befs_fs_type);
}
/*
* Macros that typecheck the init and exit functions,
* ensures that they are called at init and cleanup,
* and eliminates warnings about unused functions.
*/
module_init(init_befs_fs)
module_exit(exit_befs_fs)