Pen. Code, § 4573

(a) Except when otherwise authorized by law, or when authorized by the person in charge of the prison or other institution referred to in this section or by an officer of the institution empowered by the person in charge of the institution to give the authorization, any person, who knowingly brings or sends into, or knowingly assists in bringing into, or sending into, any state prison, prison road camp, prison forestry camp, or other prison camp or prison farm or any other place where prisoners of the state are located under the custody of prison officials, officers or employees, or into any county, city and county, or city jail, road camp, farm or other place where prisoners or inmates are located under custody of any sheriff, chief of police, peace officer, probation officer or employees, or within the grounds belonging to the institution, any controlled substance, the possession of which is prohibited by Division 10 (commencing with Section 11000) of the Health and Safety Code, any device, contrivance, instrument, or paraphernalia intended to be used for unlawfully injecting or consuming a controlled substance, is guilty of a felony punishable by imprisonment pursuant to subdivision (h) of Section 1170 for two, three, or four years.

(b) The prohibitions and sanctions addressed in this section shall be clearly and prominently posted outside of, and at the entrance to, the grounds of all detention facilities under the jurisdiction of, or operated by, the state or any city, county, or city and county.