kernel/git/stable/linux.git/fs/overlayfs, branch linux-5.5.y

ovl: fix value of i_ino for lower hardlink corner case

2020-04-21T07:06:31+00:00

commit 300b124fcf6ad2cd99a7b721e0f096785e0a3134 upstream. Commit 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more cases"), relaxed the condition nfs_export=on in order to set the value of i_ino to xino map of real ino. Specifically, it also relaxed the pre-condition that index=on for consistent i_ino. This opened the corner case of lower hardlink in ovl_get_inode(), which calls ovl_fill_inode() with ino=0 and then ovl_init_inode() is called to set i_ino to lower real ino without the xino mapping. Pass the correct values of ino;fsid in this case to ovl_fill_inode(), so it can initialize i_ino correctly. Fixes: 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more ...") Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix lseek overflow on 32bit

2020-02-11T12:36:55+00:00

commit a4ac9d45c0cd14a2adc872186431c79804b77dbf upstream. ovl_lseek() is using ssize_t to return the value from vfs_llseek(). On a 32-bit kernel ssize_t is a 32-bit signed int, which overflows above 2 GB. Assign the return value of vfs_llseek() to loff_t to fix this. Reported-by: Boris Gjenero Fixes: 9e46b840c705 ("ovl: support stacked SEEK_HOLE/SEEK_DATA") Cc: # v4.19 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

2020-02-11T12:36:55+00:00

commit 4c37e71b713ecffe81f8e6273c6835e54306d412 upstream. The WARN_ON() that child entry is always on overlay st_dev became wrong when we allowed this function to update d_ino in non-samefs setup with xino enabled. It is not true in case of xino bits overflow on a non-dir inode. Leave the WARN_ON() only for directories, where assertion is still true. Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino") Cc: # v4.17+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

Merge tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2019-12-14T19:13:54+00:00

Pull overlayfs fixes from Miklos Szeredi: "Fix some bugs and documentation" * tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: docs: filesystems: overlayfs: Fix restview warnings docs: filesystems: overlayfs: Rename overlayfs.txt to .rst ovl: relax WARN_ON() on rename to self ovl: fix corner case of non-unique st_dev;st_ino ovl: don't use a temp buf for encoding real fh ovl: make sure that real fid is 32bit aligned in memory ovl: fix lookup failure on multi lower squashfs

ovl: relax WARN_ON() on rename to self

2019-12-10T15:00:55+00:00

In ovl_rename(), if new upper is hardlinked to old upper underneath overlayfs before upper dirs are locked, user will get an ESTALE error and a WARN_ON will be printed. Changes to underlying layers while overlayfs is mounted may result in unexpected behavior, but it shouldn't crash the kernel and it shouldn't trigger WARN_ON() either, so relax this WARN_ON(). Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com Fixes: 804032fabb3b ("ovl: don't check rename to self") Cc: # v4.9+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix corner case of non-unique st_dev;st_ino

2019-12-10T15:00:55+00:00

On non-samefs overlay without xino, non pure upper inodes should use a pseudo_dev assigned to each unique lower fs and pure upper inodes use the real upper st_dev. It is fine for an overlay pure upper inode to use the same st_dev;st_ino values as the real upper inode, because the content of those two different filesystem objects is always the same. In this case, however: - two filesystems, A and B - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B Non pure upper overlay inode, whose origin is in layer 1 will have the same st_dev;st_ino values as the real lower inode. This may result with a false positive results of 'diff' between the real lower and copied up overlay inode. Fix this by using the upper st_dev;st_ino values in this case. This breaks the property of constant st_dev;st_ino across copy up of this case. This breakage will be fixed by a later patch. Fixes: 5148626b806a ("ovl: allocate anon bdev per unique lower fs") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: don't use a temp buf for encoding real fh

2019-12-10T15:00:55+00:00

We can allocate maximum fh size and encode into it directly. Suggested-by: Al Viro Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: make sure that real fid is 32bit aligned in memory

2019-12-10T15:00:55+00:00

Seprate on-disk encoding from in-memory and on-wire resresentation of overlay file handle. In-memory and on-wire we only ever pass around pointers to struct ovl_fh, which encapsulates at offset 3 the on-disk format struct ovl_fb. struct ovl_fb encapsulates at offset 21 the real file handle. That makes sure that the real file handle is always 32bit aligned in-memory when passed down to the underlying filesystem. On-disk format remains the same and store/load are done into correctly aligned buffer. New nfs exported file handles are exported with aligned real fid. Old nfs file handles are copied to an aligned buffer before being decoded. Reported-by: Al Viro Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix lookup failure on multi lower squashfs

2019-12-10T15:00:55+00:00

In the past, overlayfs required that lower fs have non null uuid in order to support nfs export and decode copy up origin file handles. Commit 9df085f3c9a2 ("ovl: relax requirement for non null uuid of lower fs") relaxed this requirement for nfs export support, as long as uuid (even if null) is unique among all lower fs. However, said commit unintentionally also relaxed the non null uuid requirement for decoding copy up origin file handles, regardless of the unique uuid requirement. Amend this mistake by disabling decoding of copy up origin file handle from lower fs with a conflicting uuid. We still encode copy up origin file handles from those fs, because file handles like those already exist in the wild and because they might provide useful information in the future. There is an unhandled corner case described by Miklos this way: - two filesystems, A and B, both have null uuid - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B In this case bad_uuid won't be set for B, because the check only involves the list of lower fs. Hence we'll try to decode a layer 2 origin on layer 1 and fail. We will deal with this corner case later. Reported-by: Colin Ian King Tested-by: Colin Ian King Link: https://lore.kernel.org/lkml/20191106234301.283006-1-colin.king@canonical.com/ Fixes: 9df085f3c9a2 ("ovl: relax requirement for non null uuid ...") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

new helper: lookup_positive_unlocked()

2019-11-15T18:49:04+00:00

Most of the callers of lookup_one_len_unlocked() treat negatives are ERR_PTR(-ENOENT). Provide a helper that would do just that. Note that a pinned positive dentry remains positive - it's ->d_inode is stable, etc.; a pinned _negative_ dentry can become positive at any point as long as you are not holding its parent at least shared. So using lookup_one_len_unlocked() needs to be careful; lookup_positive_unlocked() is safer and that's what the callers end up open-coding anyway. Signed-off-by: Al Viro