From bb0d2b8ad29630b580ac903f989e704e23462357 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Fri, 29 Jul 2016 12:05:23 +0200 Subject: [PATCH] ovl: fix sgid on directory When creating directory in workdir, the group/sgid inheritance from the parent dir was omitted completely. Fix this by calling inode_init_owner() on overlay inode and using the resulting uid/gid/mode to create the file. Unfortunately the sgid bit can be stripped off due to umask, so need to reset the mode in this case in workdir before moving the directory in place. Reported-by: Eryu Guan Signed-off-by: Miklos Szeredi --- fs/overlayfs/dir.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 7195306e9f84..8beeed34dad6 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -357,6 +357,21 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, if (err) goto out_dput2; + /* + * mode could have been mutilated due to umask (e.g. sgid directory) + */ + if (!S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { + struct iattr attr = { + .ia_valid = ATTR_MODE, + .ia_mode = stat->mode, + }; + inode_lock(newdentry->d_inode); + err = notify_change(newdentry, &attr, NULL); + inode_unlock(newdentry->d_inode); + if (err) + goto out_cleanup; + } + if (S_ISDIR(stat->mode)) { err = ovl_set_opaque(newdentry); if (err) @@ -397,7 +412,6 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, const struct cred *old_cred; struct cred *override_cred; struct kstat stat = { - .mode = mode, .rdev = rdev, }; @@ -410,12 +424,15 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, if (err) goto out_iput; + inode_init_owner(inode, dentry->d_parent->d_inode, mode); + stat.mode = inode->i_mode; + old_cred = ovl_override_creds(dentry->d_sb); err = -ENOMEM; override_cred = prepare_creds(); if (override_cred) { - override_cred->fsuid = old_cred->fsuid; - override_cred->fsgid = old_cred->fsgid; + override_cred->fsuid = inode->i_uid; + override_cred->fsgid = inode->i_gid; put_cred(override_creds(override_cred)); put_cred(override_cred); @@ -427,8 +444,14 @@ static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, link, hardlink); } revert_creds(old_cred); - if (!err) + if (!err) { + struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); + + WARN_ON(inode->i_mode != realinode->i_mode); + WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); + WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); inode = NULL; + } out_iput: iput(inode); out: -- 2.30.2