locks: only validate the lock vs. f_mode in F_SETLK codepaths
v2: replace missing break in switch statement (as pointed out by Dave
Jones)
commit bce7560d4946 (locks: consolidate checks for compatible
filp->f_mode values in setlk handlers) introduced a regression in the
F_GETLK handler.
flock64_to_posix_lock is a shared codepath between F_GETLK and F_SETLK,
but the f_mode checks should only be applicable to the F_SETLK codepaths
according to POSIX.
Instead of just reverting the patch, add a new function to do this
checking and have the F_SETLK handlers call it.
Cc: Dave Jones <davej@redhat.com>
Reported-and-Tested-by: Reuben Farrelly <reuben@reub.net>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
diff --git a/fs/locks.c b/fs/locks.c
index e663aea..e390bd9 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -389,18 +389,6 @@
fl->fl_ops = NULL;
fl->fl_lmops = NULL;
- /* Ensure that fl->fl_filp has compatible f_mode */
- switch (l->l_type) {
- case F_RDLCK:
- if (!(filp->f_mode & FMODE_READ))
- return -EBADF;
- break;
- case F_WRLCK:
- if (!(filp->f_mode & FMODE_WRITE))
- return -EBADF;
- break;
- }
-
return assign_type(fl, l->l_type);
}
@@ -2034,6 +2022,22 @@
return error;
}
+/* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
+static int
+check_fmode_for_setlk(struct file_lock *fl)
+{
+ switch (fl->fl_type) {
+ case F_RDLCK:
+ if (!(fl->fl_file->f_mode & FMODE_READ))
+ return -EBADF;
+ break;
+ case F_WRLCK:
+ if (!(fl->fl_file->f_mode & FMODE_WRITE))
+ return -EBADF;
+ }
+ return 0;
+}
+
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
@@ -2071,6 +2075,10 @@
if (error)
goto out;
+ error = check_fmode_for_setlk(file_lock);
+ if (error)
+ goto out;
+
/*
* If the cmd is requesting file-private locks, then set the
* FL_OFDLCK flag and override the owner.
@@ -2206,6 +2214,10 @@
if (error)
goto out;
+ error = check_fmode_for_setlk(file_lock);
+ if (error)
+ goto out;
+
/*
* If the cmd is requesting file-private locks, then set the
* FL_OFDLCK flag and override the owner.
