California Code, Penal Code - PEN § 16750

(a) As used in Section 25400, “lawful possession of the firearm” means that the person who has possession or custody of the firearm either lawfully owns the firearm or has the permission of the lawful owner or a person who otherwise has apparent authority to possess or have custody of the firearm. A person who takes a firearm without the permission of the lawful owner or without the permission of a person who has lawful custody of the firearm does not have lawful possession of the firearm.

(b) As used in Article 2 (commencing with Section 25850), Article 3 (commencing with Section 25900), and Article 4 (commencing with Section 26000) of Chapter 3 of Division 5 of Title 4, Chapter 6 (commencing with Section 26350) of Division 5 of Title 4, and Chapter 7 (commencing with Section 26400) of Division 5 of Title 4, “lawful possession of the firearm” means that the person who has possession or custody of the firearm either lawfully acquired and lawfully owns the firearm or has the permission of the lawful owner or person who otherwise has apparent authority to possess or have custody of the firearm. A person who takes a firearm without the permission of the lawful owner or without the permission of a person who has lawful custody of the firearm does not have lawful possession of the firearm.