o Merge contents of struct pcred into struct ucred. Specifically, add the

  real uid, saved uid, real gid, and saved gid to ucred, as well as the
  pcred->pc_uidinfo, which was associated with the real uid, only rename
  it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
  corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
  original macro that pointed.
  p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
  p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
  cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
  cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
  we figure out locking and optimizations; generally speaking, this
  means moving to a structure like this:
        newcred = crdup(oldcred);
        ...
        p->p_ucred = newcred;
        crfree(oldcred);
  It's not race-free, but better than nothing.  There are also races
  in sys_process.c, all inter-process authorization, fork, exec, and
  exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
  remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
  use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
  pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
  allocation.
o Clean up ktrcanset() to take into account changes, and move to using
  suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
  calls to better document current behavior.  In a couple of places,
  current behavior is a little questionable and we need to check
  POSIX.1 to make sure it's "right".  More commenting work still
  remains to be done.
o Update credential management calls, such as crfree(), to take into
  account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
      change_euid()
      change_egid()
      change_ruid()
      change_rgid()
      change_svuid()
      change_svgid()
  In each case, the call now acts on a credential not a process, and as
  such no longer requires more complicated process locking/etc.  They
  now assume the caller will do any necessary allocation of an
  exclusive credential reference.  Each is commented to document its
  reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
  and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
  questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
  processes and pcreds.  Note that this authorization, as well as
  CANSIGIO(), needs to be updated to use the p_cansignal() and
  p_cansched() centralized authorization routines, as they currently
  do not take into account some desirable restrictions that are handled
  by the centralized routines, as well as being inconsistent with other
  similar authorization instances.
o Update libkvm to take these changes into account.

Obtained from:	TrustedBSD Project
Reviewed by:	green, bde, jhb, freebsd-arch, freebsd-audit

1 files changed, 12 insertions, 3 deletions

diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h
index c48df00cc37e..356cca284946 100644
--- a/sys/sys/ucred.h
+++ b/sys/sys/ucred.h
@@ -50,9 +50,14 @@
 struct ucred {
 	u_int	cr_ref;			/* reference count */
 	uid_t	cr_uid;			/* effective user id */
+	uid_t	cr_ruid;		/* real user id */
+	uid_t	cr_svuid;		/* saved user id */
 	short	cr_ngroups;		/* number of groups */
 	gid_t	cr_groups[NGROUPS];	/* groups */
-	struct	uidinfo *cr_uidinfo;	/* per uid resource consumption */
+	gid_t	cr_rgid;		/* real group id */
+	gid_t	cr_svgid;		/* saved user id */
+	struct	uidinfo *cr_uidinfo;	/* per euid resource consumption */
+	struct	uidinfo *cr_ruidinfo;	/* per ruid resource consumption */
 	struct	prison *cr_prison;	/* jail(4) */
 	struct	mtx cr_mtx;		/* protect refcount */
 };
@@ -77,8 +82,12 @@ struct xucred {
 
 struct proc;
 
-void		change_euid __P((struct proc *p, uid_t euid));
-void		change_ruid __P((struct proc *p, uid_t ruid));
+void		change_egid __P((struct ucred *newcred, gid_t egid));
+void		change_euid __P((struct ucred *newcred, uid_t euid));
+void		change_rgid __P((struct ucred *newcred, gid_t rgid));
+void		change_ruid __P((struct ucred *newcred, uid_t ruid));
+void		change_svgid __P((struct ucred *newcred, gid_t svgid));
+void		change_svuid __P((struct ucred *newcred, uid_t svuid));
 struct ucred	*crcopy __P((struct ucred *cr));
 struct ucred	*crdup __P((struct ucred *cr));
 void		crfree __P((struct ucred *cr));