[PATCH v3] fs/fcntl: restore checking against COMPAT_LOFF_T_MAX for F_GETLK64

From: Vitaly Lipatov
Date: Tue Nov 14 2017 - 11:57:05 EST


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@xxxxxxxxxxx>
---
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
+ * off_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_LOFF_T_MAX);
if (err)
return err;
err = put_compat_flock64(&flock, compat_ptr(arg));
--
2.10.4