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ovl: pass an explicit reference of creators creds to callers

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ovl_setup_cred_for_create() decrements one refcount of new creds and
ovl_revert_creds() in callers decrements the last refcount.

In preparation to revert_creds_light() back to caller creds, pass an
explicit reference of the creators creds to the callers and drop the
refcount explicitly in the callers after ovl_revert_creds().

Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
This commit is contained in:
Amir Goldstein 2024-11-14 09:36:35 +01:00
parent fc5a1d2287
commit 711747e204
1 changed files with 22 additions and 12 deletions
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34
fs/overlayfs/dir.c
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@ -553,15 +553,17 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
goto out_dput;
}
static int ovl_setup_cred_for_create(struct dentry *dentry, struct inode *inode,
umode_t mode, const struct cred *old_cred)
static const struct cred *ovl_setup_cred_for_create(struct dentry *dentry,
struct inode *inode,
umode_t mode,
const struct cred *old_cred)
{
int err;
struct cred *override_cred;
override_cred = prepare_creds();
if (!override_cred)
return -ENOMEM;
return ERR_PTR(-ENOMEM);
override_cred->fsuid = inode->i_uid;
override_cred->fsgid = inode->i_gid;
@ -569,19 +571,18 @@ static int ovl_setup_cred_for_create(struct dentry *dentry, struct inode *inode,
old_cred, override_cred);
if (err) {
put_cred(override_cred);
return err;
return ERR_PTR(err);
}
put_cred(override_creds(override_cred));
put_cred(override_cred);
return 0;
return override_cred;
}
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;
const struct cred *old_cred, *new_cred = NULL;
struct dentry *parent = dentry->d_parent;
old_cred = ovl_override_creds(dentry->d_sb);
@ -610,9 +611,13 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
* create a new inode, so just use the ovl mounter's
* fs{u,g}id.
*/
err = ovl_setup_cred_for_create(dentry, inode, attr->mode, old_cred);
if (err)
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 (!ovl_dentry_is_whiteout(dentry))
@ -622,6 +627,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
out_revert_creds:
ovl_revert_creds(old_cred);
put_cred(new_cred);
return err;
}
@ -1306,7 +1312,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
struct inode *inode, umode_t mode)
{
const struct cred *old_cred;
const struct cred *old_cred, *new_cred = NULL;
struct path realparentpath;
struct file *realfile;
struct dentry *newdentry;
@ -1315,9 +1321,12 @@ static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
int err;
old_cred = ovl_override_creds(dentry->d_sb);
err = ovl_setup_cred_for_create(dentry, inode, mode, old_cred);
if (err)
new_cred = ovl_setup_cred_for_create(dentry, inode, mode, old_cred);
err = PTR_ERR(new_cred);
if (IS_ERR(new_cred)) {
new_cred = NULL;
goto out_revert_creds;
}
ovl_path_upper(dentry->d_parent, &realparentpath);
realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath,
@ -1338,6 +1347,7 @@ static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
}
out_revert_creds:
ovl_revert_creds(old_cred);
put_cred(new_cred);
return err;
}