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| author |   Amir Goldstein <amir73il@gmail.com> | 2018-11-14 16:01:34 +0200 |
|---|---|---|
| committer |   Miklos Szeredi <mszeredi@redhat.com> | 2018-11-19 16:21:29 +0100 |
| commit | 91ff20f34e94424e586f57f4f593beae16504f86 (patch) | |
| tree | 0ced724127ec90e38c993af075847ea37b00f52e /fs/overlayfs | |
| parent | Linux 4.20-rc3 (diff) | |
| download | linux-dev-91ff20f34e94424e586f57f4f593beae16504f86.tar.xz linux-dev-91ff20f34e94424e586f57f4f593beae16504f86.zip | |
ovl: fix missing override creds in link of a metacopy upper
Theodore Ts'o reported a v4.19 regression with docker-dropbox:
https://marc.info/?l=linux-fsdevel&m=154070089431116&w=2
"I was rebuilding my dropbox Docker container, and it failed in 4.19
with the following error:
...
dpkg: error: error creating new backup file \
'/var/lib/dpkg/status-old': Invalid cross-device link"
The problem did not reproduce with metacopy feature disabled.
The error was caused by insufficient credentials to set
"trusted.overlay.redirect" xattr on link of a metacopy file.
Reproducer:
echo Y > /sys/module/overlay/parameters/redirect_dir
echo Y > /sys/module/overlay/parameters/metacopy
cd /tmp
mkdir l u w m
chmod 777 l u
touch l/foo
ln l/foo l/link
chmod 666 l/foo
mount -t overlay none -olowerdir=l,upperdir=u,workdir=w m
su fsgqa
ln m/foo m/bar
[ 21.455823] overlayfs: failed to set redirect (-1)
ln: failed to create hard link 'm/bar' => 'm/foo':\
Invalid cross-device link
Reported-by: Theodore Y. Ts'o <tytso@mit.edu>
Reported-by: Maciej Zięba <maciekz82@gmail.com>
Fixes: 4120fe64dce4 ("ovl: Set redirect on upper inode when it is linked")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/dir.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index c6289147c787..82c129bfe58d 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -651,6 +651,18 @@ static int ovl_symlink(struct inode *dir, struct dentry *dentry, return ovl_create_object(dentry, S_IFLNK, 0, link); } +static int ovl_set_link_redirect(struct dentry *dentry) +{ + const struct cred *old_cred; + int err; + + old_cred = ovl_override_creds(dentry->d_sb); + err = ovl_set_redirect(dentry, false); + revert_creds(old_cred); + + return err; +} + static int ovl_link(struct dentry *old, struct inode *newdir, struct dentry *new) { @@ -670,7 +682,7 @@ static int ovl_link(struct dentry *old, struct inode *newdir, goto out_drop_write; if (ovl_is_metacopy_dentry(old)) { - err = ovl_set_redirect(old, false); + err = ovl_set_link_redirect(old); if (err) goto out_drop_write; } |