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ovl: port ovl_create_tmpfile() to new ovl_override_creator_creds cleanup guard 

This clearly indicates the double-credential override and makes the code
a lot easier to grasp with one glance.

Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-prepare-v2-2-bd1c97a36d7b@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 10:34:39 +01:00
parent f37b334728
commit 8d7fc461e4
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 25 additions and 25 deletions
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50
fs/overlayfs/dir.c
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@ -1381,7 +1381,6 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
static int ovl_create_tmpfile(struct file *file, struct dentry *dentry, static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
struct inode *inode, umode_t mode) struct inode *inode, umode_t mode)
{ {
const struct cred *new_cred __free(put_cred) = NULL;
struct path realparentpath; struct path realparentpath;
struct file *realfile; struct file *realfile;
struct ovl_file *of; struct ovl_file *of;
@ -1390,33 +1389,34 @@ static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
int flags = file->f_flags | OVL_OPEN_FLAGS; int flags = file->f_flags | OVL_OPEN_FLAGS;
int err; int err;
scoped_class(override_creds_ovl, old_cred, dentry->d_sb) { with_ovl_creds(dentry->d_sb) {
new_cred = ovl_setup_cred_for_create(dentry, inode, mode, old_cred); scoped_class(ovl_override_creator_creds, cred, dentry, inode, mode) {
if (IS_ERR(new_cred)) if (IS_ERR(cred))
return PTR_ERR(new_cred); return PTR_ERR(cred);
ovl_path_upper(dentry->d_parent, &realparentpath); ovl_path_upper(dentry->d_parent, &realparentpath);
realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath, realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath,
mode, current_cred()); mode, current_cred());
err = PTR_ERR_OR_ZERO(realfile); err = PTR_ERR_OR_ZERO(realfile);
pr_debug("tmpfile/open(%pd2, 0%o) = %i\n", realparentpath.dentry, mode, err); pr_debug("tmpfile/open(%pd2, 0%o) = %i\n", realparentpath.dentry, mode, err);
if (err) if (err)
return err; return err;
of = ovl_file_alloc(realfile); of = ovl_file_alloc(realfile);
if (!of) { if (!of) {
fput(realfile); fput(realfile);
return -ENOMEM; return -ENOMEM;
} }
/* ovl_instantiate() consumes the newdentry reference on success */ /* ovl_instantiate() consumes the newdentry reference on success */
newdentry = dget(realfile->f_path.dentry); newdentry = dget(realfile->f_path.dentry);
err = ovl_instantiate(dentry, inode, newdentry, false, file); err = ovl_instantiate(dentry, inode, newdentry, false, file);
if (!err) { if (!err) {
file->private_data = of; file->private_data = of;
} else { } else {
dput(newdentry); dput(newdentry);
ovl_file_free(of); ovl_file_free(of);
}
} }
} }
return err; return err;