linux-kernel - [v2.6.34-stable 020/165] locks: fix checking of fcntl

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Message-ID: <1345060109-9187-21-git-send-email-paul.gortmaker@windriver.com>
Date:	Wed, 15 Aug 2012 15:46:04 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	<stable@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:	"J. Bruce Fields" <bfields@...ldses.org>,
	"J. Bruce Fields" <bfields@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [v2.6.34-stable 020/165] locks: fix checking of fcntl_setlease argument

From: "J. Bruce Fields" <bfields@...ldses.org>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 0ec4f431eb56d633da3a55da67d5c4b88886ccc7 upstream.

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 8d657eb3b438 "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. ]

Signed-off-by: J. Bruce Fields <bfields@...hat.com>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 fs/locks.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index ab24d49..8cedfbf 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -291,7 +291,7 @@ 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:
@@ -444,7 +444,7 @@ 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;
@@ -462,7 +462,7 @@ 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;
-- 
1.7.12.rc2

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