locks: fix checking of fcntl_setlease argument

The only checks of the long argument passed to fcntl(fd,F_SETLEASE,.)
are done after converting the long to an int.  Thus some illegal values
may be let through and cause problems in later code.

[ They actually *don't* cause problems in mainline, as of Dave Jones's
  commit 8d657eb3b4 "Remove easily user-triggerable BUG from
  generic_setlease", but we should fix this anyway.  And this patch will
  be necessary to fix real bugs on earlier kernels. ]

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
J. Bruce Fields 2012-07-23 15:17:17 -04:00 committed by Linus Torvalds
parent a66d2c8f7e
commit 0ec4f431eb

View File

@ -308,7 +308,7 @@ static int flock_make_lock(struct file *filp, struct file_lock **lock,
return 0;
}
static int assign_type(struct file_lock *fl, int type)
static int assign_type(struct file_lock *fl, long type)
{
switch (type) {
case F_RDLCK:
@ -445,7 +445,7 @@ static const struct lock_manager_operations lease_manager_ops = {
/*
* Initialize a lease, use the default lock manager operations
*/
static int lease_init(struct file *filp, int type, struct file_lock *fl)
static int lease_init(struct file *filp, long type, struct file_lock *fl)
{
if (assign_type(fl, type) != 0)
return -EINVAL;
@ -463,7 +463,7 @@ static int lease_init(struct file *filp, int type, struct file_lock *fl)
}
/* Allocate a file_lock initialised to this type of lease */
static struct file_lock *lease_alloc(struct file *filp, int type)
static struct file_lock *lease_alloc(struct file *filp, long type)
{
struct file_lock *fl = locks_alloc_lock();
int error = -ENOMEM;