linux/fs/affs/super.c
Mikulas Patocka 01d6e08711 affs: fix remount failure when there are no options changed
Commit c8f33d0bec ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: c8f33d0bec ("affs: kstrdup() memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v4.1+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 16:50:24 -07:00

653 lines
16 KiB
C

/*
* linux/fs/affs/inode.c
*
* (c) 1996 Hans-Joachim Widmaier - Rewritten
*
* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
*
* (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
*
* (C) 1991 Linus Torvalds - minix filesystem
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/statfs.h>
#include <linux/parser.h>
#include <linux/magic.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include "affs.h"
static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
static int affs_remount (struct super_block *sb, int *flags, char *data);
static void
affs_commit_super(struct super_block *sb, int wait)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
struct buffer_head *bh = sbi->s_root_bh;
struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
lock_buffer(bh);
secs_to_datestamp(ktime_get_real_seconds(), &tail->disk_change);
affs_fix_checksum(sb, bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
if (wait)
sync_dirty_buffer(bh);
}
static void
affs_put_super(struct super_block *sb)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
pr_debug("%s()\n", __func__);
cancel_delayed_work_sync(&sbi->sb_work);
}
static int
affs_sync_fs(struct super_block *sb, int wait)
{
affs_commit_super(sb, wait);
return 0;
}
static void flush_superblock(struct work_struct *work)
{
struct affs_sb_info *sbi;
struct super_block *sb;
sbi = container_of(work, struct affs_sb_info, sb_work.work);
sb = sbi->sb;
spin_lock(&sbi->work_lock);
sbi->work_queued = 0;
spin_unlock(&sbi->work_lock);
affs_commit_super(sb, 1);
}
void affs_mark_sb_dirty(struct super_block *sb)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
unsigned long delay;
if (sb->s_flags & MS_RDONLY)
return;
spin_lock(&sbi->work_lock);
if (!sbi->work_queued) {
delay = msecs_to_jiffies(dirty_writeback_interval * 10);
queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
sbi->work_queued = 1;
}
spin_unlock(&sbi->work_lock);
}
static struct kmem_cache * affs_inode_cachep;
static struct inode *affs_alloc_inode(struct super_block *sb)
{
struct affs_inode_info *i;
i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
if (!i)
return NULL;
i->vfs_inode.i_version = 1;
i->i_lc = NULL;
i->i_ext_bh = NULL;
i->i_pa_cnt = 0;
return &i->vfs_inode;
}
static void affs_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
}
static void affs_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, affs_i_callback);
}
static void init_once(void *foo)
{
struct affs_inode_info *ei = (struct affs_inode_info *) foo;
sema_init(&ei->i_link_lock, 1);
sema_init(&ei->i_ext_lock, 1);
inode_init_once(&ei->vfs_inode);
}
static int __init init_inodecache(void)
{
affs_inode_cachep = kmem_cache_create("affs_inode_cache",
sizeof(struct affs_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
if (affs_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(affs_inode_cachep);
}
static const struct super_operations affs_sops = {
.alloc_inode = affs_alloc_inode,
.destroy_inode = affs_destroy_inode,
.write_inode = affs_write_inode,
.evict_inode = affs_evict_inode,
.put_super = affs_put_super,
.sync_fs = affs_sync_fs,
.statfs = affs_statfs,
.remount_fs = affs_remount,
.show_options = generic_show_options,
};
enum {
Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
};
static const match_table_t tokens = {
{Opt_bs, "bs=%u"},
{Opt_mode, "mode=%o"},
{Opt_mufs, "mufs"},
{Opt_notruncate, "nofilenametruncate"},
{Opt_prefix, "prefix=%s"},
{Opt_protect, "protect"},
{Opt_reserved, "reserved=%u"},
{Opt_root, "root=%u"},
{Opt_setgid, "setgid=%u"},
{Opt_setuid, "setuid=%u"},
{Opt_verbose, "verbose"},
{Opt_volume, "volume=%s"},
{Opt_ignore, "grpquota"},
{Opt_ignore, "noquota"},
{Opt_ignore, "quota"},
{Opt_ignore, "usrquota"},
{Opt_err, NULL},
};
static int
parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
/* Fill in defaults */
*uid = current_uid();
*gid = current_gid();
*reserved = 2;
*root = -1;
*blocksize = -1;
volume[0] = ':';
volume[1] = 0;
*mount_opts = 0;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token, n, option;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_bs:
if (match_int(&args[0], &n))
return 0;
if (n != 512 && n != 1024 && n != 2048
&& n != 4096) {
pr_warn("Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
return 0;
}
*blocksize = n;
break;
case Opt_mode:
if (match_octal(&args[0], &option))
return 0;
*mode = option & 0777;
affs_set_opt(*mount_opts, SF_SETMODE);
break;
case Opt_mufs:
affs_set_opt(*mount_opts, SF_MUFS);
break;
case Opt_notruncate:
affs_set_opt(*mount_opts, SF_NO_TRUNCATE);
break;
case Opt_prefix:
*prefix = match_strdup(&args[0]);
if (!*prefix)
return 0;
affs_set_opt(*mount_opts, SF_PREFIX);
break;
case Opt_protect:
affs_set_opt(*mount_opts, SF_IMMUTABLE);
break;
case Opt_reserved:
if (match_int(&args[0], reserved))
return 0;
break;
case Opt_root:
if (match_int(&args[0], root))
return 0;
break;
case Opt_setgid:
if (match_int(&args[0], &option))
return 0;
*gid = make_kgid(current_user_ns(), option);
if (!gid_valid(*gid))
return 0;
affs_set_opt(*mount_opts, SF_SETGID);
break;
case Opt_setuid:
if (match_int(&args[0], &option))
return 0;
*uid = make_kuid(current_user_ns(), option);
if (!uid_valid(*uid))
return 0;
affs_set_opt(*mount_opts, SF_SETUID);
break;
case Opt_verbose:
affs_set_opt(*mount_opts, SF_VERBOSE);
break;
case Opt_volume: {
char *vol = match_strdup(&args[0]);
if (!vol)
return 0;
strlcpy(volume, vol, 32);
kfree(vol);
break;
}
case Opt_ignore:
/* Silently ignore the quota options */
break;
default:
pr_warn("Unrecognized mount option \"%s\" or missing value\n",
p);
return 0;
}
}
return 1;
}
/* This function definitely needs to be split up. Some fine day I'll
* hopefully have the guts to do so. Until then: sorry for the mess.
*/
static int affs_fill_super(struct super_block *sb, void *data, int silent)
{
struct affs_sb_info *sbi;
struct buffer_head *root_bh = NULL;
struct buffer_head *boot_bh;
struct inode *root_inode = NULL;
s32 root_block;
int size, blocksize;
u32 chksum;
int num_bm;
int i, j;
kuid_t uid;
kgid_t gid;
int reserved;
unsigned long mount_flags;
int tmp_flags; /* fix remount prototype... */
u8 sig[4];
int ret;
save_mount_options(sb, data);
pr_debug("read_super(%s)\n", data ? (const char *)data : "no options");
sb->s_magic = AFFS_SUPER_MAGIC;
sb->s_op = &affs_sops;
sb->s_flags |= MS_NODIRATIME;
sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
sbi->sb = sb;
mutex_init(&sbi->s_bmlock);
spin_lock_init(&sbi->symlink_lock);
spin_lock_init(&sbi->work_lock);
INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
&blocksize,&sbi->s_prefix,
sbi->s_volume, &mount_flags)) {
pr_err("Error parsing options\n");
return -EINVAL;
}
/* N.B. after this point s_prefix must be released */
sbi->s_flags = mount_flags;
sbi->s_mode = i;
sbi->s_uid = uid;
sbi->s_gid = gid;
sbi->s_reserved= reserved;
/* Get the size of the device in 512-byte blocks.
* If we later see that the partition uses bigger
* blocks, we will have to change it.
*/
size = i_size_read(sb->s_bdev->bd_inode) >> 9;
pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
affs_set_blocksize(sb, PAGE_SIZE);
/* Try to find root block. Its location depends on the block size. */
i = bdev_logical_block_size(sb->s_bdev);
j = PAGE_SIZE;
if (blocksize > 0) {
i = j = blocksize;
size = size / (blocksize / 512);
}
for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
sbi->s_root_block = root_block;
if (root_block < 0)
sbi->s_root_block = (reserved + size - 1) / 2;
pr_debug("setting blocksize to %d\n", blocksize);
affs_set_blocksize(sb, blocksize);
sbi->s_partition_size = size;
/* The root block location that was calculated above is not
* correct if the partition size is an odd number of 512-
* byte blocks, which will be rounded down to a number of
* 1024-byte blocks, and if there were an even number of
* reserved blocks. Ideally, all partition checkers should
* report the real number of blocks of the real blocksize,
* but since this just cannot be done, we have to try to
* find the root block anyways. In the above case, it is one
* block behind the calculated one. So we check this one, too.
*/
for (num_bm = 0; num_bm < 2; num_bm++) {
pr_debug("Dev %s, trying root=%u, bs=%d, "
"size=%d, reserved=%d\n",
sb->s_id,
sbi->s_root_block + num_bm,
blocksize, size, reserved);
root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
if (!root_bh)
continue;
if (!affs_checksum_block(sb, root_bh) &&
be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
sbi->s_hashsize = blocksize / 4 - 56;
sbi->s_root_block += num_bm;
goto got_root;
}
affs_brelse(root_bh);
root_bh = NULL;
}
}
if (!silent)
pr_err("No valid root block on device %s\n", sb->s_id);
return -EINVAL;
/* N.B. after this point bh must be released */
got_root:
/* Keep super block in cache */
sbi->s_root_bh = root_bh;
root_block = sbi->s_root_block;
/* Find out which kind of FS we have */
boot_bh = sb_bread(sb, 0);
if (!boot_bh) {
pr_err("Cannot read boot block\n");
return -EINVAL;
}
memcpy(sig, boot_bh->b_data, 4);
brelse(boot_bh);
chksum = be32_to_cpu(*(__be32 *)sig);
/* Dircache filesystems are compatible with non-dircache ones
* when reading. As long as they aren't supported, writing is
* not recommended.
*/
if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
|| chksum == MUFS_DCOFS) && !(sb->s_flags & MS_RDONLY)) {
pr_notice("Dircache FS - mounting %s read only\n", sb->s_id);
sb->s_flags |= MS_RDONLY;
}
switch (chksum) {
case MUFS_FS:
case MUFS_INTLFFS:
case MUFS_DCFFS:
affs_set_opt(sbi->s_flags, SF_MUFS);
/* fall thru */
case FS_INTLFFS:
case FS_DCFFS:
affs_set_opt(sbi->s_flags, SF_INTL);
break;
case MUFS_FFS:
affs_set_opt(sbi->s_flags, SF_MUFS);
break;
case FS_FFS:
break;
case MUFS_OFS:
affs_set_opt(sbi->s_flags, SF_MUFS);
/* fall thru */
case FS_OFS:
affs_set_opt(sbi->s_flags, SF_OFS);
sb->s_flags |= MS_NOEXEC;
break;
case MUFS_DCOFS:
case MUFS_INTLOFS:
affs_set_opt(sbi->s_flags, SF_MUFS);
case FS_DCOFS:
case FS_INTLOFS:
affs_set_opt(sbi->s_flags, SF_INTL);
affs_set_opt(sbi->s_flags, SF_OFS);
sb->s_flags |= MS_NOEXEC;
break;
default:
pr_err("Unknown filesystem on device %s: %08X\n",
sb->s_id, chksum);
return -EINVAL;
}
if (affs_test_opt(mount_flags, SF_VERBOSE)) {
u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
pr_notice("Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
len > 31 ? 31 : len,
AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
sig, sig[3] + '0', blocksize);
}
sb->s_flags |= MS_NODEV | MS_NOSUID;
sbi->s_data_blksize = sb->s_blocksize;
if (affs_test_opt(sbi->s_flags, SF_OFS))
sbi->s_data_blksize -= 24;
tmp_flags = sb->s_flags;
ret = affs_init_bitmap(sb, &tmp_flags);
if (ret)
return ret;
sb->s_flags = tmp_flags;
/* set up enough so that it can read an inode */
root_inode = affs_iget(sb, root_block);
if (IS_ERR(root_inode))
return PTR_ERR(root_inode);
if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL))
sb->s_d_op = &affs_intl_dentry_operations;
else
sb->s_d_op = &affs_dentry_operations;
sb->s_root = d_make_root(root_inode);
if (!sb->s_root) {
pr_err("AFFS: Get root inode failed\n");
return -ENOMEM;
}
pr_debug("s_flags=%lX\n", sb->s_flags);
return 0;
}
static int
affs_remount(struct super_block *sb, int *flags, char *data)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
int blocksize;
kuid_t uid;
kgid_t gid;
int mode;
int reserved;
int root_block;
unsigned long mount_flags;
int res = 0;
char *new_opts;
char volume[32];
char *prefix = NULL;
new_opts = kstrdup(data, GFP_KERNEL);
if (data && !new_opts)
return -ENOMEM;
pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data);
sync_filesystem(sb);
*flags |= MS_NODIRATIME;
memcpy(volume, sbi->s_volume, 32);
if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
&blocksize, &prefix, volume,
&mount_flags)) {
kfree(prefix);
kfree(new_opts);
return -EINVAL;
}
flush_delayed_work(&sbi->sb_work);
if (new_opts)
replace_mount_options(sb, new_opts);
sbi->s_flags = mount_flags;
sbi->s_mode = mode;
sbi->s_uid = uid;
sbi->s_gid = gid;
/* protect against readers */
spin_lock(&sbi->symlink_lock);
if (prefix) {
kfree(sbi->s_prefix);
sbi->s_prefix = prefix;
}
memcpy(sbi->s_volume, volume, 32);
spin_unlock(&sbi->symlink_lock);
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
return 0;
if (*flags & MS_RDONLY)
affs_free_bitmap(sb);
else
res = affs_init_bitmap(sb, flags);
return res;
}
static int
affs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
int free;
u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
pr_debug("%s() partsize=%d, reserved=%d\n",
__func__, AFFS_SB(sb)->s_partition_size,
AFFS_SB(sb)->s_reserved);
free = affs_count_free_blocks(sb);
buf->f_type = AFFS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
buf->f_bfree = free;
buf->f_bavail = free;
buf->f_fsid.val[0] = (u32)id;
buf->f_fsid.val[1] = (u32)(id >> 32);
buf->f_namelen = AFFSNAMEMAX;
return 0;
}
static struct dentry *affs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
}
static void affs_kill_sb(struct super_block *sb)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
kill_block_super(sb);
if (sbi) {
affs_free_bitmap(sb);
affs_brelse(sbi->s_root_bh);
kfree(sbi->s_prefix);
mutex_destroy(&sbi->s_bmlock);
kfree(sbi);
}
}
static struct file_system_type affs_fs_type = {
.owner = THIS_MODULE,
.name = "affs",
.mount = affs_mount,
.kill_sb = affs_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("affs");
static int __init init_affs_fs(void)
{
int err = init_inodecache();
if (err)
goto out1;
err = register_filesystem(&affs_fs_type);
if (err)
goto out;
return 0;
out:
destroy_inodecache();
out1:
return err;
}
static void __exit exit_affs_fs(void)
{
unregister_filesystem(&affs_fs_type);
destroy_inodecache();
}
MODULE_DESCRIPTION("Amiga filesystem support for Linux");
MODULE_LICENSE("GPL");
module_init(init_affs_fs)
module_exit(exit_affs_fs)