PM/libsys: extend getepinfo, add getsockcred(3)

The service-only getepinfo(2) PM call returns information about a
given endpoint.  This patch extends that call so that it returns
enough information to allow correctly filling a sockcred structure.
A new getsockcred(3) function is added to libsys to fill an actual
sockcred structure with the obtained information.  However, for the
caller's convenience, the groups list is kept separate.

Change-Id: I9f1a6d1a221c77eabaa3498ff4ec9a5fb922e4fd

minix/include/minix/ipc.h

@@ -1398,8 +1398,10 @@ _ASSERT_MSG_SIZE(mess_lsys_pci_busc_get_bar);
 
 typedef struct {
 	endpoint_t endpt;
+	vir_bytes groups;
+	int ngroups;
 
-	uint8_t padding[52];
+	uint8_t padding[44];
 } mess_lsys_pm_getepinfo;
 _ASSERT_MSG_SIZE(mess_lsys_pm_getepinfo);
 
@@ -1713,9 +1715,12 @@ _ASSERT_MSG_SIZE(mess_pm_lexec_exec_new);
 
 typedef struct {
 	uid_t uid;
+	uid_t euid;
 	gid_t gid;
+	gid_t egid;
+	int ngroups;
 
-	uint8_t padding[48];
+	uint8_t padding[36];
 } mess_pm_lsys_getepinfo;
 _ASSERT_MSG_SIZE(mess_pm_lsys_getepinfo);
 

minix/include/minix/syslib.h

@@ -17,6 +17,7 @@
 /* Forward declaration */
 struct rs_pci;
 struct rusage;
+struct sockcred;
 
 #define SYSTASK SYSTEM
 
@@ -270,6 +271,8 @@ pid_t getepinfo(endpoint_t proc_ep, uid_t *uidp, gid_t *gidp);
 pid_t getnpid(endpoint_t proc_ep);
 uid_t getnuid(endpoint_t proc_ep);
 gid_t getngid(endpoint_t proc_ep);
+int getsockcred(endpoint_t proc_ep, struct sockcred * sockcred, gid_t * groups,
+	int ngroups);
 int socketpath(endpoint_t endpt, char *path, size_t size, int what, dev_t *dev,
 	ino_t *ino);
 #define SPATH_CHECK	0	/* check user permissions on socket path */

minix/lib/libsys/getepinfo.c

@@ -2,7 +2,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include <sys/ucred.h>
+#include <sys/socket.h>
 
 pid_t
 getepinfo(endpoint_t proc_ep, uid_t *uid, gid_t *gid)
@@ -12,14 +12,16 @@ getepinfo(endpoint_t proc_ep, uid_t *uid, gid_t *gid)
 
 	memset(&m, 0, sizeof(m));
 	m.m_lsys_pm_getepinfo.endpt = proc_ep;
+	m.m_lsys_pm_getepinfo.groups = (vir_bytes)NULL;
+	m.m_lsys_pm_getepinfo.ngroups = 0;
 
 	if ((r = _taskcall(PM_PROC_NR, PM_GETEPINFO, &m)) < 0)
 		return r;
 
 	if (uid != NULL)
-		*uid = m.m_pm_lsys_getepinfo.uid;
+		*uid = m.m_pm_lsys_getepinfo.euid;
 	if (gid != NULL)
-		*gid = m.m_pm_lsys_getepinfo.gid;
+		*gid = m.m_pm_lsys_getepinfo.egid;
 	return (pid_t) r;
 }
 
@@ -52,3 +54,27 @@ getngid(endpoint_t proc_ep)
 
 	return gid;
 }
+
+int
+getsockcred(endpoint_t proc_ep, struct sockcred * sockcred, gid_t * groups,
+	int ngroups)
+{
+	message m;
+	int r;
+
+	memset(&m, 0, sizeof(m));
+	m.m_lsys_pm_getepinfo.endpt = proc_ep;
+	m.m_lsys_pm_getepinfo.groups = (vir_bytes)groups;
+	m.m_lsys_pm_getepinfo.ngroups = ngroups;
+
+	if ((r = _taskcall(PM_PROC_NR, PM_GETEPINFO, &m)) < 0)
+		return r;
+
+	sockcred->sc_uid = m.m_pm_lsys_getepinfo.uid;
+	sockcred->sc_euid = m.m_pm_lsys_getepinfo.euid;
+	sockcred->sc_gid = m.m_pm_lsys_getepinfo.gid;
+	sockcred->sc_egid = m.m_pm_lsys_getepinfo.egid;
+	sockcred->sc_ngroups = m.m_pm_lsys_getepinfo.ngroups;
+
+	return OK;
+}

minix/servers/pm/misc.c

@@ -170,15 +170,25 @@ int do_getepinfo(void)
 {
   struct mproc *rmp;
   endpoint_t ep;
-  int slot;
+  int r, slot, ngroups;
 
   ep = m_in.m_lsys_pm_getepinfo.endpt;
   if (pm_isokendpt(ep, &slot) != OK)
 	return(ESRCH);
-
   rmp = &mproc[slot];
-  mp->mp_reply.m_pm_lsys_getepinfo.uid = rmp->mp_effuid;
+
-  mp->mp_reply.m_pm_lsys_getepinfo.gid = rmp->mp_effgid;
+  mp->mp_reply.m_pm_lsys_getepinfo.uid = rmp->mp_realuid;
+  mp->mp_reply.m_pm_lsys_getepinfo.euid = rmp->mp_effuid;
+  mp->mp_reply.m_pm_lsys_getepinfo.gid = rmp->mp_realgid;
+  mp->mp_reply.m_pm_lsys_getepinfo.egid = rmp->mp_effgid;
+  mp->mp_reply.m_pm_lsys_getepinfo.ngroups = ngroups = rmp->mp_ngroups;
+  if (ngroups > m_in.m_lsys_pm_getepinfo.ngroups)
+	ngroups = m_in.m_lsys_pm_getepinfo.ngroups;
+  if (ngroups > 0) {
+	if ((r = sys_datacopy(SELF, (vir_bytes)rmp->mp_sgroups, who_e,
+	    m_in.m_lsys_pm_getepinfo.groups, ngroups * sizeof(gid_t))) != OK)
+		return(r);
+  }
   return(rmp->mp_pid);
 }