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ovl: port ovl_create_or_link() to cred guard

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Use the scoped ovl cred guard.

Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-3-b31603935724@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner
2025-11-17 10:33:34 +01:00
parent 87809f12e0
commit 8c9531edcf
1 changed files with 32 additions and 40 deletions
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72
fs/overlayfs/dir.c
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@@ -618,52 +618,44 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct ovl_cattr *attr, bool origin)
{
int err;
const struct cred *old_cred, *new_cred = NULL;
const struct cred *new_cred __free(put_cred) = NULL;
struct dentry *parent = dentry->d_parent;
old_cred = ovl_override_creds(dentry->d_sb);
/*
* When linking a file with copy up origin into a new parent, mark the
* new parent dir "impure".
*/
if (origin) {
err = ovl_set_impure(parent, ovl_dentry_upper(parent));
if (err)
goto out_revert_creds;
}
if (!attr->hardlink) {
scoped_class(override_creds_ovl, old_cred, dentry->d_sb) {
/*
* In the creation cases(create, mkdir, mknod, symlink),
* ovl should transfer current's fs{u,g}id to underlying
* fs. Because underlying fs want to initialize its new
* inode owner using current's fs{u,g}id. And in this
* case, the @inode is a new inode that is initialized
* in inode_init_owner() to current's fs{u,g}id. So use
* the inode's i_{u,g}id to override the cred's fs{u,g}id.
*
* But in the other hardlink case, ovl_link() does not
* create a new inode, so just use the ovl mounter's
* fs{u,g}id.
* When linking a file with copy up origin into a new parent, mark the
* new parent dir "impure".
*/
new_cred = ovl_setup_cred_for_create(dentry, inode, attr->mode,
old_cred);
err = PTR_ERR(new_cred);
if (IS_ERR(new_cred)) {
new_cred = NULL;
goto out_revert_creds;
if (origin) {
err = ovl_set_impure(parent, ovl_dentry_upper(parent));
if (err)
return err;
}
if (!attr->hardlink) {
/*
* In the creation cases(create, mkdir, mknod, symlink),
* ovl should transfer current's fs{u,g}id to underlying
* fs. Because underlying fs want to initialize its new
* inode owner using current's fs{u,g}id. And in this
* case, the @inode is a new inode that is initialized
* in inode_init_owner() to current's fs{u,g}id. So use
* the inode's i_{u,g}id to override the cred's fs{u,g}id.
*
* But in the other hardlink case, ovl_link() does not
* create a new inode, so just use the ovl mounter's
* fs{u,g}id.
*/
new_cred = ovl_setup_cred_for_create(dentry, inode, attr->mode, old_cred);
if (IS_ERR(new_cred))
return PTR_ERR(new_cred);
}
if (!ovl_dentry_is_whiteout(dentry))
return ovl_create_upper(dentry, inode, attr);
return ovl_create_over_whiteout(dentry, inode, attr);
}
if (!ovl_dentry_is_whiteout(dentry))
err = ovl_create_upper(dentry, inode, attr);
else
err = ovl_create_over_whiteout(dentry, inode, attr);
out_revert_creds:
ovl_revert_creds(old_cred);
put_cred(new_cred);
return err;
}