If the real user ID, effective user ID, or saved set-user-ID previously had the value 0 and, as a result of the changes to the user IDs, all three of these IDs have a nonzero value, then the permitted and effective capability sets are cleared (i.e., all capabilities are permanently dropped).

If the effective user ID is changed from 0 to a nonzero value, then the effective capability set is cleared (i.e., the effective capabilities are dropped, but those in the permitted set can be raised again).

If the effective user ID is changed from a nonzero value to 0, then the permitted capability set is copied into the effective capability set (i.e., all permitted capabilities become effective).

If the file-system user ID is changed from 0 to a nonzero value, then the following file-related capabilities are cleared from the effective capability set: CAP_CHOWN, CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH, CAP_FOWNER, CAP_FSETID, CAP_LINUX_IMMUTABLE (since Linux 2.6.30), CAP_MAC_OVERRIDE, and CAP_MKNOD (since Linux 2.6.30). Conversely, if the file-system user ID is changed from a nonzero value to 0, then any of these capabilities that are enabled in the permitted set are enabled in the effective set. These manipulations are done to maintain the traditional semantics for manipulations of the Linux-specific file-system user ID.