Instead write a proper compat syscall that calls common helpers.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/fcntl.c | 118 +++++++++++++++++++++++++++++++++++--------------------------
fs/locks.c | 2 +-
2 files changed, 68 insertions(+), 52 deletions(-)
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 671ac43c65df..9d909b029063 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -505,76 +505,92 @@ convert_fcntl_cmd(unsigned int cmd)
return 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
+ * -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)
+{
+ if (flock.l_start > COMPAT_OFF_T_MAX)
+ return -EOVERFLOW;
+ if (flock.l_len > COMPAT_OFF_T_MAX)
+ flock.l_len = COMPAT_OFF_T_MAX;
+ return 0;
+}
+
COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
- mm_segment_t old_fs;
- struct flock f;
- long ret;
- unsigned int conv_cmd;
+ struct fd f = fdget_raw(fd);
+ struct flock flock;
+ long err = -EBADF;
+
+ if (!f.file)
+ return err;
+
+ if (unlikely(f.file->f_mode & FMODE_PATH)) {
+ if (!check_fcntl_cmd(cmd))
+ goto out_put;
+ }
+
+ err = security_file_fcntl(f.file, cmd, arg);
+ if (err)
+ goto out_put;
switch (cmd) {
case F_GETLK:
+ err = get_compat_flock(&flock, compat_ptr(arg));
+ if (err)
+ break;
+ err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
+ if (err)
+ break;
+ err = fixup_compat_flock(&flock);
+ if (err)
+ return err;
+ err = put_compat_flock(&flock, compat_ptr(arg));
+ break;
+ case F_GETLK64:
+ case F_OFD_GETLK:
+ err = get_compat_flock64(&flock, compat_ptr(arg));
+ if (err)
+ break;
+ err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
+ if (err)
+ break;
+ err = fixup_compat_flock(&flock);
+ if (err)
+ return err;
+ err = put_compat_flock64(&flock, compat_ptr(arg));
+ break;
case F_SETLK:
case F_SETLKW:
- ret = get_compat_flock(&f, compat_ptr(arg));
- if (ret != 0)
+ err = get_compat_flock(&flock, compat_ptr(arg));
+ if (err)
break;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- ret = sys_fcntl(fd, cmd, (unsigned long)&f);
- set_fs(old_fs);
- if (cmd == F_GETLK && ret == 0) {
- /* 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
- * -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
- */
-
- if (f.l_start > COMPAT_OFF_T_MAX)
- ret = -EOVERFLOW;
- if (f.l_len > COMPAT_OFF_T_MAX)
- f.l_len = COMPAT_OFF_T_MAX;
- if (ret == 0)
- ret = put_compat_flock(&f, compat_ptr(arg));
- }
+ err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
-
- case F_GETLK64:
case F_SETLK64:
case F_SETLKW64:
- case F_OFD_GETLK:
case F_OFD_SETLK:
case F_OFD_SETLKW:
- ret = get_compat_flock64(&f, compat_ptr(arg));
- if (ret != 0)
+ err = get_compat_flock64(&flock, compat_ptr(arg));
+ if (err)
break;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- conv_cmd = convert_fcntl_cmd(cmd);
- ret = sys_fcntl(fd, conv_cmd, (unsigned long)&f);
- set_fs(old_fs);
- if ((conv_cmd == F_GETLK || conv_cmd == F_OFD_GETLK) && ret == 0) {
- /* need to return lock information - see above for commentary */
- if (f.l_start > COMPAT_LOFF_T_MAX)
- ret = -EOVERFLOW;
- if (f.l_len > COMPAT_LOFF_T_MAX)
- f.l_len = COMPAT_LOFF_T_MAX;
- if (ret == 0)
- ret = put_compat_flock64(&f, compat_ptr(arg));
- }
+ err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
-
default:
- ret = sys_fcntl(fd, cmd, arg);
+ err = do_fcntl(fd, cmd, arg, f.file);
break;
}
- return ret;
+out_put:
+ fdput(f);
+ return err;
}
COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
diff --git a/fs/locks.c b/fs/locks.c
index 054f6fb7641e..8b4e78e4c054 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2325,7 +2325,7 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
if (error)
goto out;
- flock.l_type = file_lock.fl_type;
+ flock->l_type = file_lock.fl_type;
if (file_lock.fl_type != F_UNLCK)
posix_lock_to_flock64(flock, &file_lock);
--
2.11.0
