linux-kernel - [PATCH v2] fs/fcntl: restore checking against COMPAT_LOFF_T_MAX for F

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Message-Id: <20171114134715.21649-1-lav@etersoft.ru>
Date:   Tue, 14 Nov 2017 16:47:15 +0300
From:   Vitaly Lipatov <lav@...rsoft.ru>
To:     lav@...rsoft.ru, wine-patches <wine-patches@...ehq.org>
Cc:     Jeff Layton <jlayton@...chiereds.net>,
        "J. Bruce Fields" <bfields@...ldses.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] fs/fcntl: restore checking against COMPAT_LOFF_T_MAX for F_GETLK64

for fcntl64 with F_GETLK64 we need use checking against COMPAT_LOFF_T_MAX.

Fixes: 94073ad77fff2 "fs/locks: don't mess with the address limit in compat_fcntl64"

Signed-off-by: Vitaly Lipatov <lav@...rsoft.ru>
---
 fs/fcntl.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 30f47d0..e9443d9 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -590,17 +590,17 @@ convert_fcntl_cmd(unsigned int cmd)
  * GETLK was successful and we need to return the data, but it needs to fit in
  * the compat structure.
  * l_start shouldn't be too big, unless the original start + end is greater than
- * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
+ * COMPAT_OFF_T_MAX/COMPAT_LOFF_T_MAX, in which case the app was asking for trouble, so we return
  * -EOVERFLOW in that case.  l_len could be too big, in which case we just
  * truncate it, and only allow the app to see that part of the conflicting lock
  * that might make sense to it anyway
  */
-static int fixup_compat_flock(struct flock *flock)
+static int fixup_compat_flock(struct flock *flock, loff_t off_t_max)
 {
-	if (flock->l_start > COMPAT_OFF_T_MAX)
+	if (flock->l_start > off_t_max)
 		return -EOVERFLOW;
-	if (flock->l_len > COMPAT_OFF_T_MAX)
-		flock->l_len = COMPAT_OFF_T_MAX;
+	if (flock->l_len > off_t_max)
+		flock->l_len = off_t_max;
 	return 0;
 }
 
@@ -631,7 +631,7 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
 		err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
 		if (err)
 			break;
-		err = fixup_compat_flock(&flock);
+		err = fixup_compat_flock(&flock, COMPAT_OFF_T_MAX);
 		if (err)
 			return err;
 		err = put_compat_flock(&flock, compat_ptr(arg));
@@ -644,7 +644,7 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
 		err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
 		if (err)
 			break;
-		err = fixup_compat_flock(&flock);
+		err = fixup_compat_flock(&flock, COMPAT_OFF_T_MAX);
 		if (err)
 			return err;
 		err = put_compat_flock64(&flock, compat_ptr(arg));
-- 
2.10.4