On Wed, Dec 11, 2013 at 05:56:16PM -0500, J. Bruce Fields wrote:
> On Wed, Dec 11, 2013 at 02:07:41PM -0500, Jeff Layton wrote:
> > On Wed, 11 Dec 2013 10:19:31 -0500
> > "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> ...
> > > + if (l->l_len > 0)
> > > + fl->fl_end = fl->fl_start + l->l_len - 1;
> > > + else if (l->l_len < 0) {
> > > + fl->fl_end = start - 1;
> >
> > Erm... I think this is not quite right...
> >
> > "start" is uninitialized here. I think this should be:
> >
> > fl->fl_end = fl->fl_start - 1
> >
> > With that too, we can get rid of the local "start" variable. I think
> > this may explain why I'm tripping over the BUG() in locks_remove_file.
>
> Yep.
>
> One other bug: I think l_start < 0 is actually fine in the
> SEEK_CUR/SEEK_END cases.
>
> With that fixed and another comment (though I don't know how much it
> helps), it looks like the below.
Alternatively, maybe we could simplify? (On top of the previous):
commit d4bf5cb021a3ac1ec07530ebda904e262cc89d11
Author: J. Bruce Fields <bfields@xxxxxxxxxx>
Date: Wed Dec 11 17:42:32 2013 -0500
locks: simplify overflow checking
Or maybe we don't actually care about indicating overflow in the 32-bit
case: sure we could fail if e.g. f_pos+start or f_pos+start+len would
exceed 32-bits, but do we really need to?
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
diff --git a/fs/locks.c b/fs/locks.c
index 39f2ca9..efbf577 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -344,8 +344,8 @@ static int assign_type(struct file_lock *fl, long type)
return 0;
}
-static int flock_to_posix_lock_common(struct file *filp, struct file_lock *fl,
- struct flock64 *l, loff_t offset_max)
+static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
+ struct flock64 *l)
{
switch (l->l_whence) {
case SEEK_SET:
@@ -360,12 +360,12 @@ static int flock_to_posix_lock_common(struct file *filp, struct file_lock *fl,
default:
return -EINVAL;
}
- if (l->l_start > offset_max - fl->fl_start)
+ if (l->l_start > OFFSET_MAX - fl->fl_start)
return -EOVERFLOW;
fl->fl_start += l->l_start;
if (fl->fl_start < 0)
return -EINVAL;
- if (l->l_len > offset_max - fl->fl_start)
+ if (l->l_len > OFFSET_MAX - fl->fl_start)
return -EOVERFLOW;
if (fl->fl_start + l->l_len < 0)
return -EINVAL;
@@ -403,22 +403,9 @@ static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
.l_len = l->l_len,
};
- /*
- * The use of OFFT_OFFSET_MAX here ensures we return -EOVERFLOW
- * if the start or end of the lock could not be represented as
- * an off_t, following SUSv3.
- */
- return flock_to_posix_lock_common(filp, fl, &ll, OFFT_OFFSET_MAX);
+ return flock64_to_posix_lock(filp, fl, &ll);
}
-#if BITS_PER_LONG == 32
-static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
- struct flock64 *l)
-{
- return flock_to_posix_lock_common(filp, fl, l, OFFSET_MAX);
-}
-#endif
-
/* default lease lock manager operations */
static void lease_break_callback(struct file_lock *fl)
{
--
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