This will make it easier to implement a sane compat fcntl syscall.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/fcntl.c | 26 ++++++++++++++----
fs/locks.c | 77 +++++++++++++++---------------------------------------
include/linux/fs.h | 8 +++---
3 files changed, 46 insertions(+), 65 deletions(-)
diff --git a/fs/fcntl.c b/fs/fcntl.c
index f4e7267d117f..671ac43c65df 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -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) {
@@ -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() */
@@ -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:
/*
@@ -384,6 +392,7 @@ SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
unsigned long, arg)
{
struct fd f = fdget_raw(fd);
+ struct flock64 flock;
long err = -EBADF;
if (!f.file)
@@ -401,14 +410,21 @@ 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(filp, 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);
diff --git a/fs/locks.c b/fs/locks.c
index af2031a1fcff..054f6fb7641e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2086,26 +2086,22 @@ 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;
@@ -2117,15 +2113,12 @@ 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:
@@ -2218,26 +2211,16 @@ 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.
*/
@@ -2246,7 +2229,7 @@ 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;
@@ -2261,7 +2244,7 @@ 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;
@@ -2270,7 +2253,7 @@ 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;
@@ -2315,26 +2298,22 @@ 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;
@@ -2348,11 +2327,7 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
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:
@@ -2363,26 +2338,16 @@ 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.
*/
@@ -2391,7 +2356,7 @@ 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;
@@ -2406,7 +2371,7 @@ 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;
@@ -2415,7 +2380,7 @@ 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;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 803e5a9b2654..aa4affb38c39 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -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);
--
2.11.0
