summaryrefslogtreecommitdiff
path: root/fs/inode.c
diff options
context:
space:
mode:
authorDarrick J. Wong <darrick.wong@oracle.com>2019-07-01 18:25:34 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2019-07-01 18:25:34 +0300
commit5aca284210ce827f780ea2f4f9c6ab8d6e2d6648 (patch)
tree485c43c3dd95105dccf7fcc32934112a76ea2129 /fs/inode.c
parentd1fdb6d8f6a4109a4263176c84b899076a5f8008 (diff)
downloadlinux-5aca284210ce827f780ea2f4f9c6ab8d6e2d6648.tar.xz
vfs: create a generic checking and prep function for FS_IOC_SETFLAGS
Create a generic function to check incoming FS_IOC_SETFLAGS flag values and later prepare the inode for updates so that we can standardize the implementations that follow ext4's flag values. Note that the efivarfs implementation no longer fails a no-op SETFLAGS without CAP_LINUX_IMMUTABLE since that's the behavior in ext*. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: David Sterba <dsterba@suse.com> Reviewed-by: Bob Peterson <rpeterso@redhat.com>
Diffstat (limited to 'fs/inode.c')
-rw-r--r--fs/inode.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/fs/inode.c b/fs/inode.c
index df6542ec3b88..8072a09fd0b9 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2170,3 +2170,27 @@ struct timespec64 current_time(struct inode *inode)
return timespec64_trunc(now, inode->i_sb->s_time_gran);
}
EXPORT_SYMBOL(current_time);
+
+/*
+ * Generic function to check FS_IOC_SETFLAGS values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
+ unsigned int flags)
+{
+ /*
+ * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+ * the relevant capability.
+ *
+ * This test looks nicer. Thanks to Pauline Middelink
+ */
+ if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
+ !capable(CAP_LINUX_IMMUTABLE))
+ return -EPERM;
+
+ return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_setflags_prepare);