@@ -571,7 +571,12 @@ static int ovl_setup_cred_for_create(struct dentry *dentry, struct inode *inode,
put_cred(override_cred);
return err;
}
- put_cred(override_creds(override_cred));
+
+ /*
+ * We must be called with creator creds already, otherwise we risk
+ * leaking creds.
+ */
+ WARN_ON_ONCE(override_creds(override_cred) != ovl_creds(dentry->d_sb));
put_cred(override_cred);
return 0;
@@ -65,12 +65,12 @@ const struct cred *ovl_override_creds(struct super_block *sb)
{
struct ovl_fs *ofs = OVL_FS(sb);
- return override_creds(ofs->creator_cred);
+ return override_creds_light(ofs->creator_cred);
}
void ovl_revert_creds(const struct cred *old_cred)
{
- revert_creds(old_cred);
+ revert_creds_light(old_cred);
}
/*
Use override_creds_light() in ovl_override_creds() and revert_creds_light() in ovl_revert_creds_light(). The _light() functions do not change the 'usage' of the credentials in question, as they refer to the credentials associated with the mounter, which have a longer lifetime. In ovl_setup_cred_for_create(), do not need to modify the mounter credentials (returned by override_creds()) 'usage' counter. Add a warning to verify that we are indeed working with the mounter credentials (stored in the superblock). Failure in this assumption means that creds may leak. Suggested-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> --- fs/overlayfs/dir.c | 7 ++++++- fs/overlayfs/util.c | 4 ++-- 2 files changed, 8 insertions(+), 3 deletions(-)