Add a comment to these operations that cannot use the _light version
of override_creds()/revert_creds(), because during the critical
section the struct cred .usage counter might be modified.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
---
fs/overlayfs/copy_up.c | 6 +++++-
fs/overlayfs/dir.c | 3 +++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index a5ef2005a2cc..7dec275e08cd 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -718,8 +718,12 @@ static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
if (err < 0)
return err;
- if (cc->new)
+ if (cc->new) {
+ /* Do not use the _light version, the credentials
+ * ->usage might be modified.
+ */
cc->old = override_creds(cc->new);
+ }
return 0;
}
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index ab65e98a1def..851945904385 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -584,6 +584,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
const struct cred *old_cred;
struct dentry *parent = dentry->d_parent;
+ /* Do not use the _light version, cred->usage might be modified */
old_cred = ovl_override_creds(dentry->d_sb);
/*
@@ -1159,6 +1160,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
goto out;
}
+ /* Do not use the _light version, cred->usage might be modified */
old_cred = ovl_override_creds(old->d_sb);
if (!list_empty(&list)) {
@@ -1314,6 +1316,7 @@ static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
int flags = file->f_flags | OVL_OPEN_FLAGS;
int err;
+ /* Do not use the _light version, cred->usage might be modified */
old_cred = ovl_override_creds(dentry->d_sb);
err = ovl_setup_cred_for_create(dentry, inode, mode, old_cred);
if (err)
--
2.46.0
