tmp_suning_uos_patched/fs/ioctl.c
Guo Xuenan 05c073b1ad fs: fix an infinite loop in iomap_fiemap
[ Upstream commit 49df34221804cfd6384135b28b03c9461a31d024 ]

when get fiemap starting from MAX_LFS_FILESIZE, (maxbytes - *len) < start
will always true , then *len set zero. because of start offset is beyond
file size, for erofs filesystem it will always return iomap.length with
zero,iomap iterate will enter infinite loop. it is necessary cover this
corner case to avoid this situation.

------------[ cut here ]------------
WARNING: CPU: 7 PID: 905 at fs/iomap/iter.c:35 iomap_iter+0x97f/0xc70
Modules linked in: xfs erofs
CPU: 7 PID: 905 Comm: iomap Tainted: G        W         5.17.0-rc8 #27
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:iomap_iter+0x97f/0xc70
Code: 85 a1 fc ff ff e8 71 be 9c ff 0f 1f 44 00 00 e9 92 fc ff ff e8 62 be 9c ff 0f 0b b8 fb ff ff ff e9 fc f8 ff ff e8 51 be 9c ff <0f> 0b e9 2b fc ff ff e8 45 be 9c ff 0f 0b e9 e1 fb ff ff e8 39 be
RSP: 0018:ffff888060a37ab0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888060a37bb0 RCX: 0000000000000000
RDX: ffff88807e19a900 RSI: ffffffff81a7da7f RDI: ffff888060a37be0
RBP: 7fffffffffffffff R08: 0000000000000000 R09: ffff888060a37c20
R10: ffff888060a37c67 R11: ffffed100c146f8c R12: 7fffffffffffffff
R13: 0000000000000000 R14: ffff888060a37bd8 R15: ffff888060a37c20
FS:  00007fd3cca01540(0000) GS:ffff888108780000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020010820 CR3: 0000000054b92000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 iomap_fiemap+0x1c9/0x2f0
 erofs_fiemap+0x64/0x90 [erofs]
 do_vfs_ioctl+0x40d/0x12e0
 __x64_sys_ioctl+0xaa/0x1c0
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
 </TASK>
---[ end trace 0000000000000000 ]---
watchdog: BUG: soft lockup - CPU#7 stuck for 26s! [iomap:905]

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[djwong: fix some typos]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-25 09:17:54 +02:00

854 lines
21 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ioctl.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/compat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/falloc.h>
#include <linux/sched/signal.h>
#include <linux/fiemap.h>
#include "internal.h"
#include <asm/ioctls.h>
/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))
/**
* vfs_ioctl - call filesystem specific ioctl methods
* @filp: open file to invoke ioctl method on
* @cmd: ioctl command to execute
* @arg: command-specific argument for ioctl
*
* Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
* returns -ENOTTY.
*
* Returns 0 on success, -errno on error.
*/
long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int error = -ENOTTY;
if (!filp->f_op->unlocked_ioctl)
goto out;
error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -ENOTTY;
out:
return error;
}
EXPORT_SYMBOL(vfs_ioctl);
static int ioctl_fibmap(struct file *filp, int __user *p)
{
struct inode *inode = file_inode(filp);
struct super_block *sb = inode->i_sb;
int error, ur_block;
sector_t block;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
error = get_user(ur_block, p);
if (error)
return error;
if (ur_block < 0)
return -EINVAL;
block = ur_block;
error = bmap(inode, &block);
if (block > INT_MAX) {
error = -ERANGE;
pr_warn_ratelimited("[%s/%d] FS: %s File: %pD4 would truncate fibmap result\n",
current->comm, task_pid_nr(current),
sb->s_id, filp);
}
if (error)
ur_block = 0;
else
ur_block = block;
if (put_user(ur_block, p))
error = -EFAULT;
return error;
}
/**
* fiemap_fill_next_extent - Fiemap helper function
* @fieinfo: Fiemap context passed into ->fiemap
* @logical: Extent logical start offset, in bytes
* @phys: Extent physical start offset, in bytes
* @len: Extent length, in bytes
* @flags: FIEMAP_EXTENT flags that describe this extent
*
* Called from file system ->fiemap callback. Will populate extent
* info as passed in via arguments and copy to user memory. On
* success, extent count on fieinfo is incremented.
*
* Returns 0 on success, -errno on error, 1 if this was the last
* extent that will fit in user array.
*/
#define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC)
#define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED)
#define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
u64 phys, u64 len, u32 flags)
{
struct fiemap_extent extent;
struct fiemap_extent __user *dest = fieinfo->fi_extents_start;
/* only count the extents */
if (fieinfo->fi_extents_max == 0) {
fieinfo->fi_extents_mapped++;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
return 1;
if (flags & SET_UNKNOWN_FLAGS)
flags |= FIEMAP_EXTENT_UNKNOWN;
if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
flags |= FIEMAP_EXTENT_ENCODED;
if (flags & SET_NOT_ALIGNED_FLAGS)
flags |= FIEMAP_EXTENT_NOT_ALIGNED;
memset(&extent, 0, sizeof(extent));
extent.fe_logical = logical;
extent.fe_physical = phys;
extent.fe_length = len;
extent.fe_flags = flags;
dest += fieinfo->fi_extents_mapped;
if (copy_to_user(dest, &extent, sizeof(extent)))
return -EFAULT;
fieinfo->fi_extents_mapped++;
if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
return 1;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
EXPORT_SYMBOL(fiemap_fill_next_extent);
/**
* fiemap_prep - check validity of requested flags for fiemap
* @inode: Inode to operate on
* @fieinfo: Fiemap context passed into ->fiemap
* @start: Start of the mapped range
* @len: Length of the mapped range, can be truncated by this function.
* @supported_flags: Set of fiemap flags that the file system understands
*
* This function must be called from each ->fiemap instance to validate the
* fiemap request against the file system parameters.
*
* Returns 0 on success, or a negative error on failure.
*/
int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 *len, u32 supported_flags)
{
u64 maxbytes = inode->i_sb->s_maxbytes;
u32 incompat_flags;
int ret = 0;
if (*len == 0)
return -EINVAL;
if (start >= maxbytes)
return -EFBIG;
/*
* Shrink request scope to what the fs can actually handle.
*/
if (*len > maxbytes || (maxbytes - *len) < start)
*len = maxbytes - start;
supported_flags |= FIEMAP_FLAG_SYNC;
supported_flags &= FIEMAP_FLAGS_COMPAT;
incompat_flags = fieinfo->fi_flags & ~supported_flags;
if (incompat_flags) {
fieinfo->fi_flags = incompat_flags;
return -EBADR;
}
if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
ret = filemap_write_and_wait(inode->i_mapping);
return ret;
}
EXPORT_SYMBOL(fiemap_prep);
static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap)
{
struct fiemap fiemap;
struct fiemap_extent_info fieinfo = { 0, };
struct inode *inode = file_inode(filp);
int error;
if (!inode->i_op->fiemap)
return -EOPNOTSUPP;
if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap)))
return -EFAULT;
if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
return -EINVAL;
fieinfo.fi_flags = fiemap.fm_flags;
fieinfo.fi_extents_max = fiemap.fm_extent_count;
fieinfo.fi_extents_start = ufiemap->fm_extents;
error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start,
fiemap.fm_length);
fiemap.fm_flags = fieinfo.fi_flags;
fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
error = -EFAULT;
return error;
}
static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
u64 off, u64 olen, u64 destoff)
{
struct fd src_file = fdget(srcfd);
loff_t cloned;
int ret;
if (!src_file.file)
return -EBADF;
ret = -EXDEV;
if (src_file.file->f_path.mnt != dst_file->f_path.mnt)
goto fdput;
cloned = vfs_clone_file_range(src_file.file, off, dst_file, destoff,
olen, 0);
if (cloned < 0)
ret = cloned;
else if (olen && cloned != olen)
ret = -EINVAL;
else
ret = 0;
fdput:
fdput(src_file);
return ret;
}
static long ioctl_file_clone_range(struct file *file,
struct file_clone_range __user *argp)
{
struct file_clone_range args;
if (copy_from_user(&args, argp, sizeof(args)))
return -EFAULT;
return ioctl_file_clone(file, args.src_fd, args.src_offset,
args.src_length, args.dest_offset);
}
#ifdef CONFIG_BLOCK
static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
{
return (offset >> inode->i_blkbits);
}
static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
{
return (blk << inode->i_blkbits);
}
/**
* __generic_block_fiemap - FIEMAP for block based inodes (no locking)
* @inode: the inode to map
* @fieinfo: the fiemap info struct that will be passed back to userspace
* @start: where to start mapping in the inode
* @len: how much space to map
* @get_block: the fs's get_block function
*
* This does FIEMAP for block based inodes. Basically it will just loop
* through get_block until we hit the number of extents we want to map, or we
* go past the end of the file and hit a hole.
*
* If it is possible to have data blocks beyond a hole past @inode->i_size, then
* please do not use this function, it will stop at the first unmapped block
* beyond i_size.
*
* If you use this function directly, you need to do your own locking. Use
* generic_block_fiemap if you want the locking done for you.
*/
static int __generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, loff_t start,
loff_t len, get_block_t *get_block)
{
struct buffer_head map_bh;
sector_t start_blk, last_blk;
loff_t isize = i_size_read(inode);
u64 logical = 0, phys = 0, size = 0;
u32 flags = FIEMAP_EXTENT_MERGED;
bool past_eof = false, whole_file = false;
int ret = 0;
ret = fiemap_prep(inode, fieinfo, start, &len, FIEMAP_FLAG_SYNC);
if (ret)
return ret;
/*
* Either the i_mutex or other appropriate locking needs to be held
* since we expect isize to not change at all through the duration of
* this call.
*/
if (len >= isize) {
whole_file = true;
len = isize;
}
/*
* Some filesystems can't deal with being asked to map less than
* blocksize, so make sure our len is at least block length.
*/
if (logical_to_blk(inode, len) == 0)
len = blk_to_logical(inode, 1);
start_blk = logical_to_blk(inode, start);
last_blk = logical_to_blk(inode, start + len - 1);
do {
/*
* we set b_size to the total size we want so it will map as
* many contiguous blocks as possible at once
*/
memset(&map_bh, 0, sizeof(struct buffer_head));
map_bh.b_size = len;
ret = get_block(inode, start_blk, &map_bh, 0);
if (ret)
break;
/* HOLE */
if (!buffer_mapped(&map_bh)) {
start_blk++;
/*
* We want to handle the case where there is an
* allocated block at the front of the file, and then
* nothing but holes up to the end of the file properly,
* to make sure that extent at the front gets properly
* marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof &&
blk_to_logical(inode, start_blk) >= isize)
past_eof = 1;
/*
* First hole after going past the EOF, this is our
* last extent
*/
if (past_eof && size) {
flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
} else if (size) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size, flags);
size = 0;
}
/* if we have holes up to/past EOF then we're done */
if (start_blk > last_blk || past_eof || ret)
break;
} else {
/*
* We have gone over the length of what we wanted to
* map, and it wasn't the entire file, so add the extent
* we got last time and exit.
*
* This is for the case where say we want to map all the
* way up to the second to the last block in a file, but
* the last block is a hole, making the second to last
* block FIEMAP_EXTENT_LAST. In this case we want to
* see if there is a hole after the second to last block
* so we can mark it properly. If we found data after
* we exceeded the length we were requesting, then we
* are good to go, just add the extent to the fieinfo
* and break
*/
if (start_blk > last_blk && !whole_file) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
break;
}
/*
* if size != 0 then we know we already have an extent
* to add, so add it.
*/
if (size) {
ret = fiemap_fill_next_extent(fieinfo, logical,
phys, size,
flags);
if (ret)
break;
}
logical = blk_to_logical(inode, start_blk);
phys = blk_to_logical(inode, map_bh.b_blocknr);
size = map_bh.b_size;
flags = FIEMAP_EXTENT_MERGED;
start_blk += logical_to_blk(inode, size);
/*
* If we are past the EOF, then we need to make sure as
* soon as we find a hole that the last extent we found
* is marked with FIEMAP_EXTENT_LAST
*/
if (!past_eof && logical + size >= isize)
past_eof = true;
}
cond_resched();
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
}
} while (1);
/* If ret is 1 then we just hit the end of the extent array */
if (ret == 1)
ret = 0;
return ret;
}
/**
* generic_block_fiemap - FIEMAP for block based inodes
* @inode: The inode to map
* @fieinfo: The mapping information
* @start: The initial block to map
* @len: The length of the extect to attempt to map
* @get_block: The block mapping function for the fs
*
* Calls __generic_block_fiemap to map the inode, after taking
* the inode's mutex lock.
*/
int generic_block_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len, get_block_t *get_block)
{
int ret;
inode_lock(inode);
ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
inode_unlock(inode);
return ret;
}
EXPORT_SYMBOL(generic_block_fiemap);
#endif /* CONFIG_BLOCK */
/*
* This provides compatibility with legacy XFS pre-allocation ioctls
* which predate the fallocate syscall.
*
* Only the l_start, l_len and l_whence fields of the 'struct space_resv'
* are used here, rest are ignored.
*/
static int ioctl_preallocate(struct file *filp, int mode, void __user *argp)
{
struct inode *inode = file_inode(filp);
struct space_resv sr;
if (copy_from_user(&sr, argp, sizeof(sr)))
return -EFAULT;
switch (sr.l_whence) {
case SEEK_SET:
break;
case SEEK_CUR:
sr.l_start += filp->f_pos;
break;
case SEEK_END:
sr.l_start += i_size_read(inode);
break;
default:
return -EINVAL;
}
return vfs_fallocate(filp, mode | FALLOC_FL_KEEP_SIZE, sr.l_start,
sr.l_len);
}
/* on ia32 l_start is on a 32-bit boundary */
#if defined CONFIG_COMPAT && defined(CONFIG_X86_64)
/* just account for different alignment */
static int compat_ioctl_preallocate(struct file *file, int mode,
struct space_resv_32 __user *argp)
{
struct inode *inode = file_inode(file);
struct space_resv_32 sr;
if (copy_from_user(&sr, argp, sizeof(sr)))
return -EFAULT;
switch (sr.l_whence) {
case SEEK_SET:
break;
case SEEK_CUR:
sr.l_start += file->f_pos;
break;
case SEEK_END:
sr.l_start += i_size_read(inode);
break;
default:
return -EINVAL;
}
return vfs_fallocate(file, mode | FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
}
#endif
static int file_ioctl(struct file *filp, unsigned int cmd, int __user *p)
{
switch (cmd) {
case FIBMAP:
return ioctl_fibmap(filp, p);
case FS_IOC_RESVSP:
case FS_IOC_RESVSP64:
return ioctl_preallocate(filp, 0, p);
case FS_IOC_UNRESVSP:
case FS_IOC_UNRESVSP64:
return ioctl_preallocate(filp, FALLOC_FL_PUNCH_HOLE, p);
case FS_IOC_ZERO_RANGE:
return ioctl_preallocate(filp, FALLOC_FL_ZERO_RANGE, p);
}
return -ENOIOCTLCMD;
}
static int ioctl_fionbio(struct file *filp, int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = O_NONBLOCK;
#ifdef __sparc__
/* SunOS compatibility item. */
if (O_NONBLOCK != O_NDELAY)
flag |= O_NDELAY;
#endif
spin_lock(&filp->f_lock);
if (on)
filp->f_flags |= flag;
else
filp->f_flags &= ~flag;
spin_unlock(&filp->f_lock);
return error;
}
static int ioctl_fioasync(unsigned int fd, struct file *filp,
int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = on ? FASYNC : 0;
/* Did FASYNC state change ? */
if ((flag ^ filp->f_flags) & FASYNC) {
if (filp->f_op->fasync)
/* fasync() adjusts filp->f_flags */
error = filp->f_op->fasync(fd, filp, on);
else
error = -ENOTTY;
}
return error < 0 ? error : 0;
}
static int ioctl_fsfreeze(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
/* If filesystem doesn't support freeze feature, return. */
if (sb->s_op->freeze_fs == NULL && sb->s_op->freeze_super == NULL)
return -EOPNOTSUPP;
/* Freeze */
if (sb->s_op->freeze_super)
return sb->s_op->freeze_super(sb);
return freeze_super(sb);
}
static int ioctl_fsthaw(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
/* Thaw */
if (sb->s_op->thaw_super)
return sb->s_op->thaw_super(sb);
return thaw_super(sb);
}
static int ioctl_file_dedupe_range(struct file *file,
struct file_dedupe_range __user *argp)
{
struct file_dedupe_range *same = NULL;
int ret;
unsigned long size;
u16 count;
if (get_user(count, &argp->dest_count)) {
ret = -EFAULT;
goto out;
}
size = offsetof(struct file_dedupe_range __user, info[count]);
if (size > PAGE_SIZE) {
ret = -ENOMEM;
goto out;
}
same = memdup_user(argp, size);
if (IS_ERR(same)) {
ret = PTR_ERR(same);
same = NULL;
goto out;
}
same->dest_count = count;
ret = vfs_dedupe_file_range(file, same);
if (ret)
goto out;
ret = copy_to_user(argp, same, size);
if (ret)
ret = -EFAULT;
out:
kfree(same);
return ret;
}
/*
* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
* It's just a simple helper for sys_ioctl and compat_sys_ioctl.
*
* When you add any new common ioctls to the switches above and below,
* please ensure they have compatible arguments in compat mode.
*/
static int do_vfs_ioctl(struct file *filp, unsigned int fd,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct inode *inode = file_inode(filp);
switch (cmd) {
case FIOCLEX:
set_close_on_exec(fd, 1);
return 0;
case FIONCLEX:
set_close_on_exec(fd, 0);
return 0;
case FIONBIO:
return ioctl_fionbio(filp, argp);
case FIOASYNC:
return ioctl_fioasync(fd, filp, argp);
case FIOQSIZE:
if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||
S_ISLNK(inode->i_mode)) {
loff_t res = inode_get_bytes(inode);
return copy_to_user(argp, &res, sizeof(res)) ?
-EFAULT : 0;
}
return -ENOTTY;
case FIFREEZE:
return ioctl_fsfreeze(filp);
case FITHAW:
return ioctl_fsthaw(filp);
case FS_IOC_FIEMAP:
return ioctl_fiemap(filp, argp);
case FIGETBSZ:
/* anon_bdev filesystems may not have a block size */
if (!inode->i_sb->s_blocksize)
return -EINVAL;
return put_user(inode->i_sb->s_blocksize, (int __user *)argp);
case FICLONE:
return ioctl_file_clone(filp, arg, 0, 0, 0);
case FICLONERANGE:
return ioctl_file_clone_range(filp, argp);
case FIDEDUPERANGE:
return ioctl_file_dedupe_range(filp, argp);
case FIONREAD:
if (!S_ISREG(inode->i_mode))
return vfs_ioctl(filp, cmd, arg);
return put_user(i_size_read(inode) - filp->f_pos,
(int __user *)argp);
default:
if (S_ISREG(inode->i_mode))
return file_ioctl(filp, cmd, argp);
break;
}
return -ENOIOCTLCMD;
}
SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
struct fd f = fdget(fd);
int error;
if (!f.file)
return -EBADF;
error = security_file_ioctl(f.file, cmd, arg);
if (error)
goto out;
error = do_vfs_ioctl(f.file, fd, cmd, arg);
if (error == -ENOIOCTLCMD)
error = vfs_ioctl(f.file, cmd, arg);
out:
fdput(f);
return error;
}
#ifdef CONFIG_COMPAT
/**
* compat_ptr_ioctl - generic implementation of .compat_ioctl file operation
*
* This is not normally called as a function, but instead set in struct
* file_operations as
*
* .compat_ioctl = compat_ptr_ioctl,
*
* On most architectures, the compat_ptr_ioctl() just passes all arguments
* to the corresponding ->ioctl handler. The exception is arch/s390, where
* compat_ptr() clears the top bit of a 32-bit pointer value, so user space
* pointers to the second 2GB alias the first 2GB, as is the case for
* native 32-bit s390 user space.
*
* The compat_ptr_ioctl() function must therefore be used only with ioctl
* functions that either ignore the argument or pass a pointer to a
* compatible data type.
*
* If any ioctl command handled by fops->unlocked_ioctl passes a plain
* integer instead of a pointer, or any of the passed data types
* is incompatible between 32-bit and 64-bit architectures, a proper
* handler is required instead of compat_ptr_ioctl.
*/
long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
if (!file->f_op->unlocked_ioctl)
return -ENOIOCTLCMD;
return file->f_op->unlocked_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
EXPORT_SYMBOL(compat_ptr_ioctl);
COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
struct fd f = fdget(fd);
int error;
if (!f.file)
return -EBADF;
/* RED-PEN how should LSM module know it's handling 32bit? */
error = security_file_ioctl(f.file, cmd, arg);
if (error)
goto out;
switch (cmd) {
/* FICLONE takes an int argument, so don't use compat_ptr() */
case FICLONE:
error = ioctl_file_clone(f.file, arg, 0, 0, 0);
break;
#if defined(CONFIG_X86_64)
/* these get messy on amd64 due to alignment differences */
case FS_IOC_RESVSP_32:
case FS_IOC_RESVSP64_32:
error = compat_ioctl_preallocate(f.file, 0, compat_ptr(arg));
break;
case FS_IOC_UNRESVSP_32:
case FS_IOC_UNRESVSP64_32:
error = compat_ioctl_preallocate(f.file, FALLOC_FL_PUNCH_HOLE,
compat_ptr(arg));
break;
case FS_IOC_ZERO_RANGE_32:
error = compat_ioctl_preallocate(f.file, FALLOC_FL_ZERO_RANGE,
compat_ptr(arg));
break;
#endif
/*
* everything else in do_vfs_ioctl() takes either a compatible
* pointer argument or no argument -- call it with a modified
* argument.
*/
default:
error = do_vfs_ioctl(f.file, fd, cmd,
(unsigned long)compat_ptr(arg));
if (error != -ENOIOCTLCMD)
break;
if (f.file->f_op->compat_ioctl)
error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -ENOTTY;
break;
}
out:
fdput(f);
return error;
}
#endif