NAME

cr_canseeothergids — determine if subjects may see entities in a disjoint group set

SYNOPSIS

int
cr_canseeothergids(struct ucred *u1, struct ucred *u2);

DESCRIPTION

This function checks if a subject associated to credentials u1 is denied seeing a subject or object associated to credentials u2 by a policy that requires both credentials to have at least one group in common. For this determination, the real and supplementary group IDs are used, but not the effective group IDs, as per realgroupmember(9).

This policy is active if and only if the sysctl(8) variable security.bsd.see_other_gids is set to zero.

As usual, the superuser (effective user ID 0) is exempt from this policy provided that the sysctl(8) variable security.bsd.suser_enabled is non-zero and no active MAC policy explicitly denies the exemption (see priv_check_cred(9)).

RETURN VALUES

The cr_canseeothergids() function returns 0 if the policy is disabled, the credentials share at least one common group, or if u1 has privilege exempting it from the policy. Otherwise, it returns ESRCH.

SEE ALSO

cr_bsd_visible(9), priv_check_cred(9), realgroupmember(9)