I guess you are using a PMOS transistor as the pass transistors as the design is LDO. One for the easily method is to use a current mirror circuit that mirror the current in the pass transistor with a certain current ratio. Then, this current is used to compare with the reference voltage (current limit) through a resistor or using a opamp to change the gate voltage of pass transistor. (Please consider the current limit loop stability beside the normal operation loop stability)
The only concern is the VDS differences between the pass transistor and the current mirror transistor. Some people used another opamp to make the same VDS voltage on the current mirror transistor.
Side effects: There are bandwidth limited issue.
More simply method is sense resistor in current path or part of current path.
Have a good time designing....