kernel.git/fs/overlayfs/super.c, branch linux-4.13.y

ovl: add NULL check in ovl_alloc_inode

2017-11-02T08:54:46Z

commit b3885bd6edb41b91a0e3976469f72ae31bfb8d95 upstream. This was detected by fault injection test Signed-off-by: Hirofumi Nakagawa Fixes: 13cf199d0088 ("ovl: allocate an ovl_inode struct") Signed-off-by: Greg Kroah-Hartman

ovl: fix regression caused by exclusive upper/work dir protection

2017-10-12T09:56:16Z

commit 85fdee1eef1a9e48ad5716916677e0c5fbc781e3 upstream. Enforcing exclusive ownership on upper/work dirs caused a docker regression: https://github.com/moby/moby/issues/34672. Euan spotted the regression and pointed to the offending commit. Vivek has brought the regression to my attention and provided this reproducer: Terminal 1: mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ Terminal 2: unshare -m Terminal 1: umount merged mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ mount: /root/overlay-testing/merged: none already mounted or mount point busy To fix the regression, I replaced the error with an alarming warning. With index feature enabled, mount does fail, but logs a suggestion to override exclusive dir protection by disabling index. Note that index=off mount does take the inuse locks, so a concurrent index=off will issue the warning and a concurrent index=on mount will fail. Documentation was updated to reflect this change. Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") Reported-by: Euan Kemp Reported-by: Vivek Goyal Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix xattr get and set with selinux

2017-07-20T09:08:21Z

inode_doinit_with_dentry() in SELinux wants to read the upper inode's xattr to get security label, and ovl_xattr_get() calls ovl_dentry_real(), which depends on dentry->d_inode, but d_inode is null and not initialized yet at this point resulting in an Oops. Fix by getting the upperdentry info from the inode directly in this case. Reported-by: Eryu Guan Fixes: 09d8b586731b ("ovl: move __upperdentry to ovl_inode") Signed-off-by: Miklos Szeredi

ovl: remove unneeded check for IS_ERR()

2017-07-13T20:06:46Z

ovl_workdir_create() returns a valid index dentry or NULL. Reported-by: Dan Carpenter Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix random return value on mount

2017-07-13T20:06:45Z

On failure to prepare_creds(), mount fails with a random return value, as err was last set to an integer cast of a valid lower mnt pointer or set to 0 if inodes index feature is enabled. Reported-by: Dan Carpenter Fixes: 3fe6e52f0626 ("ovl: override creds with the ones from ...") Cc: # v4.7 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: cleanup orphan index entries

2017-07-04T20:03:19Z

index entry should live only as long as there are upper or lower hardlinks. Cleanup orphan index entries on mount and when dropping the last overlay inode nlink. When about to cleanup or link up to orphan index and the index inode nlink > 1, admit that something went wrong and adjust overlay nlink to index inode nlink - 1 to prevent it from dropping below zero. This could happen when adding lower hardlinks underneath a mounted overlay and then trying to unlink them. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: add flag for upper in ovl_entry

2017-07-04T20:03:18Z

For rename, we need to ensure that an upper alias exists for hard links before attempting the operation. Introduce a flag in ovl_entry to track the state of the upper alias. Signed-off-by: Miklos Szeredi

ovl: cleanup bad and stale index entries on mount

2017-07-04T20:03:17Z

Bad index entries are entries whose name does not match the origin file handle stored in trusted.overlay.origin xattr. Bad index entries could be a result of a system power off in the middle of copy up. Stale index entries are entries whose origin file handle is stale. Stale index entries could be a result of copying layers or removing lower entries while the overlay is not mounted. The case of copying layers should be detected earlier by the verification of upper root dir origin and index dir origin. Both bad and stale index entries are detected and removed on mount. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: verify index dir matches upper dir

2017-07-04T20:03:17Z

An index dir contains persistent hardlinks to files in upper dir. Therefore, we must never mount an existing index dir with a differnt upper dir. Store the upper root dir file handle in index dir inode when index dir is created and verify the file handle before using an existing index dir on mount. Add an 'is_upper' flag to the overlay file handle encoding and set it when encoding the upper root file handle. This is not critical for index dir verification, but it is good practice towards a standard overlayfs file handle format for NFS export. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: verify upper root dir matches lower root dir

2017-07-04T20:03:17Z

When inodes index feature is enabled, verify that the file handle stored in upper root dir matches the lower root dir or fail to mount. If upper root dir has no stored file handle, encode and store the lower root dir file handle in overlay.origin xattr. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi