ceph: add additional offset check in ceph_write_iter()

If the offset is larger or equal to both real file size and
max file size, then return -EFBIG.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 2c54d2674db6..b9cd9d271dcb 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1384,12 +1384,12 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
         struct ceph_file_info *fi = file->private_data;
         struct inode *inode = file_inode(file);
         struct ceph_inode_info *ci = ceph_inode(inode);
-        struct ceph_osd_client *osdc =
-                &ceph_sb_to_client(inode->i_sb)->client->osdc;
+        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
         struct ceph_cap_flush *prealloc_cf;
         ssize_t count, written = 0;
         int err, want, got;
         loff_t pos;
+        loff_t limit = max(i_size_read(inode), fsc->max_file_size);
 
         if (ceph_snap(inode) != CEPH_NOSNAP)
                 return -EROFS;
@@ -1415,6 +1415,13 @@ retry_snap:
                 goto out;
 
         pos = iocb->ki_pos;
+        if (unlikely(pos >= limit)) {
+                err = -EFBIG;
+                goto out;
+        } else {
+                iov_iter_truncate(from, limit - pos);
+        }
+
         count = iov_iter_count(from);
         if (ceph_quota_is_max_bytes_exceeded(inode, pos + count)) {
                 err = -EDQUOT;
@@ -1436,7 +1443,7 @@ retry_snap:
         }
 
         /* FIXME: not complete since it doesn't account for being at quota */
-        if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL)) {
+        if (ceph_osdmap_flag(&fsc->client->osdc, CEPH_OSDMAP_FULL)) {
                 err = -ENOSPC;
                 goto out;
         }
@@ -1526,7 +1533,7 @@ retry_snap:
         }
 
         if (written >= 0) {
-                if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_NEARFULL))
+                if (ceph_osdmap_flag(&fsc->client->osdc, CEPH_OSDMAP_NEARFULL))
                         iocb->ki_flags |= IOCB_DSYNC;
                 written = generic_write_sync(iocb, written);
         }