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| author | Miklos Szeredi <miklos@szeredi.hu> | 2015-12-04 19:18:48 +0100 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-12-06 12:28:23 -0500 |
| commit | acff81ec2c79492b180fade3c2894425cd35a545 (patch) | |
| tree | da3c7514877f6881b8be76e203614917227be52a | |
| parent | 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8 (diff) | |
| download | lwn-acff81ec2c79492b180fade3c2894425cd35a545.tar.gz lwn-acff81ec2c79492b180fade3c2894425cd35a545.zip | |
ovl: fix permission checking for setattr
[Al Viro] The bug is in being too enthusiastic about optimizing ->setattr()
away - instead of "copy verbatim with metadata" + "chmod/chown/utimes"
(with the former being always safe and the latter failing in case of
insufficient permissions) it tries to combine these two. Note that copyup
itself will have to do ->setattr() anyway; _that_ is where the elevated
capabilities are right. Having these two ->setattr() (one to set verbatim
copy of metadata, another to do what overlayfs ->setattr() had been asked
to do in the first place) combined is where it breaks.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/overlayfs/inode.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index ec0c2a050043..961284936917 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -49,13 +49,13 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) if (err) goto out; - upperdentry = ovl_dentry_upper(dentry); - if (upperdentry) { + err = ovl_copy_up(dentry); + if (!err) { + upperdentry = ovl_dentry_upper(dentry); + mutex_lock(&upperdentry->d_inode->i_mutex); err = notify_change(upperdentry, attr, NULL); mutex_unlock(&upperdentry->d_inode->i_mutex); - } else { - err = ovl_copy_up_last(dentry, attr, false); } ovl_drop_write(dentry); out: |