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fs/locks: pass kernel struct flock to fcntl_getlk/setlk
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This will make it easier to implement a sane compat fcntl syscall.

[ jlayton: fix undeclared identifiers in 32-bit fcntl64 syscall handler ]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
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Christoph Hellwig authored and Jeff Layton committed May 27, 2017
1 parent 80b79dd commit a75d30c
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Showing 3 changed files with 48 additions and 66 deletions.
27 changes: 22 additions & 5 deletions fs/fcntl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,8 @@ static int f_getowner_uids(struct file *filp, unsigned long arg)
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
struct file *filp)
{
void __user *argp = (void __user *)arg;
struct flock flock;
long err = -EINVAL;

switch (cmd) {
Expand Down Expand Up @@ -273,7 +275,11 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
case F_OFD_GETLK:
#endif
case F_GETLK:
err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
if (copy_from_user(&flock, argp, sizeof(flock)))
return -EFAULT;
err = fcntl_getlk(filp, cmd, &flock);
if (!err && copy_to_user(argp, &flock, sizeof(flock)))
return -EFAULT;
break;
#if BITS_PER_LONG != 32
/* 32-bit arches must use fcntl64() */
Expand All @@ -283,7 +289,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
/* Fallthrough */
case F_SETLK:
case F_SETLKW:
err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
if (copy_from_user(&flock, argp, sizeof(flock)))
return -EFAULT;
err = fcntl_setlk(fd, filp, cmd, &flock);
break;
case F_GETOWN:
/*
Expand Down Expand Up @@ -383,7 +391,9 @@ SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
unsigned long, arg)
{
void __user *argp = (void __user *)arg;
struct fd f = fdget_raw(fd);
struct flock64 flock;
long err = -EBADF;

if (!f.file)
Expand All @@ -401,14 +411,21 @@ SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
switch (cmd) {
case F_GETLK64:
case F_OFD_GETLK:
err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
err = -EFAULT;
if (copy_from_user(&flock, argp, sizeof(flock)))
break;
err = fcntl_getlk64(f.file, cmd, &flock);
if (!err && copy_to_user(argp, &flock, sizeof(flock)))
err = -EFAULT;
break;
case F_SETLK64:
case F_SETLKW64:
case F_OFD_SETLK:
case F_OFD_SETLKW:
err = fcntl_setlk64(fd, f.file, cmd,
(struct flock64 __user *) arg);
err = -EFAULT;
if (copy_from_user(&flock, argp, sizeof(flock)))
break;
err = fcntl_setlk64(fd, f.file, cmd, &flock);
break;
default:
err = do_fcntl(fd, cmd, arg, f.file);
Expand Down
79 changes: 22 additions & 57 deletions fs/locks.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2084,26 +2084,22 @@ static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
{
struct file_lock file_lock;
struct flock flock;
int error;

error = -EFAULT;
if (copy_from_user(&flock, l, sizeof(flock)))
goto out;
error = -EINVAL;
if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
goto out;

error = flock_to_posix_lock(filp, &file_lock, &flock);
error = flock_to_posix_lock(filp, &file_lock, flock);
if (error)
goto out;

if (cmd == F_OFD_GETLK) {
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_GETLK;
Expand All @@ -2115,15 +2111,12 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
if (error)
goto out;

flock.l_type = file_lock.fl_type;
flock->l_type = file_lock.fl_type;
if (file_lock.fl_type != F_UNLCK) {
error = posix_lock_to_flock(&flock, &file_lock);
error = posix_lock_to_flock(flock, &file_lock);
if (error)
goto rel_priv;
}
error = -EFAULT;
if (!copy_to_user(l, &flock, sizeof(flock)))
error = 0;
rel_priv:
locks_release_private(&file_lock);
out:
Expand Down Expand Up @@ -2216,26 +2209,16 @@ check_fmode_for_setlk(struct file_lock *fl)
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
struct flock __user *l)
struct flock *flock)
{
struct file_lock *file_lock = locks_alloc_lock();
struct flock flock;
struct inode *inode;
struct inode *inode = locks_inode(filp);
struct file *f;
int error;

if (file_lock == NULL)
return -ENOLCK;

inode = locks_inode(filp);

/*
* This might block, so we do it before checking the inode.
*/
error = -EFAULT;
if (copy_from_user(&flock, l, sizeof(flock)))
goto out;

/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
Expand All @@ -2244,7 +2227,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
goto out;
}

error = flock_to_posix_lock(filp, file_lock, &flock);
error = flock_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;

Expand All @@ -2259,7 +2242,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
switch (cmd) {
case F_OFD_SETLK:
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_SETLK;
Expand All @@ -2268,7 +2251,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
break;
case F_OFD_SETLKW:
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_SETLKW;
Expand Down Expand Up @@ -2313,26 +2296,22 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
{
struct file_lock file_lock;
struct flock64 flock;
int error;

error = -EFAULT;
if (copy_from_user(&flock, l, sizeof(flock)))
goto out;
error = -EINVAL;
if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
goto out;

error = flock64_to_posix_lock(filp, &file_lock, &flock);
error = flock64_to_posix_lock(filp, &file_lock, flock);
if (error)
goto out;

if (cmd == F_OFD_GETLK) {
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_GETLK64;
Expand All @@ -2344,13 +2323,9 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
if (error)
goto out;

flock.l_type = file_lock.fl_type;
flock->l_type = file_lock.fl_type;
if (file_lock.fl_type != F_UNLCK)
posix_lock_to_flock64(&flock, &file_lock);

error = -EFAULT;
if (!copy_to_user(l, &flock, sizeof(flock)))
error = 0;
posix_lock_to_flock64(flock, &file_lock);

locks_release_private(&file_lock);
out:
Expand All @@ -2361,26 +2336,16 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
struct flock64 __user *l)
struct flock64 *flock)
{
struct file_lock *file_lock = locks_alloc_lock();
struct flock64 flock;
struct inode *inode;
struct inode *inode = locks_inode(filp);
struct file *f;
int error;

if (file_lock == NULL)
return -ENOLCK;

/*
* This might block, so we do it before checking the inode.
*/
error = -EFAULT;
if (copy_from_user(&flock, l, sizeof(flock)))
goto out;

inode = locks_inode(filp);

/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
Expand All @@ -2389,7 +2354,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
goto out;
}

error = flock64_to_posix_lock(filp, file_lock, &flock);
error = flock64_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;

Expand All @@ -2404,7 +2369,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
switch (cmd) {
case F_OFD_SETLK:
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_SETLK64;
Expand All @@ -2413,7 +2378,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
break;
case F_OFD_SETLKW:
error = -EINVAL;
if (flock.l_pid != 0)
if (flock->l_pid != 0)
goto out;

cmd = F_SETLKW64;
Expand Down
8 changes: 4 additions & 4 deletions include/linux/fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1038,14 +1038,14 @@ static inline struct inode *locks_inode(const struct file *f)
}

#ifdef CONFIG_FILE_LOCKING
extern int fcntl_getlk(struct file *, unsigned int, struct flock __user *);
extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
struct flock __user *);
struct flock *);

#if BITS_PER_LONG == 32
extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 __user *);
extern int fcntl_getlk64(struct file *, unsigned int, struct flock64 *);
extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
struct flock64 __user *);
struct flock64 *);
#endif

extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
Expand Down

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