(( Resending my last from a client that (hopefully) won't mangle the email.
   Sorry about the noise, folks. ))


Hello OpenBSD Community -

OpenBSD should have the ability to prevent users from seeing each other's 
processes even if this ability is disabled by default. 
In addition to the small security benefit this provides, it also affords each 
user a much greater amount of privacy. Linux and 
FreeBSD already support similar features ( 
https://www.cyberciti.biz/faq/linux-hide-processes-from-other-users/  && 
https://www.cyberciti.biz/faq/freebsd-disable-ps-sockstat-command-information-leakage/
 ) and the implementation itself is fairly 
trivial.

Below is a patch which implements basic process hiding for non-superusers and 
is activated with a sysctl knob. Similar to that of 
FreeBSD it is called "kern.see_other_uids¨. The idea is that if process spying 
is a security or privacy concern for you, you 
would add "kern.see_other_uids=0" to sysctl.conf and reboot (assuming 
securelevel > 0).

I look forward to your comments.

Thanks and cheers all -
Ian Walker



Index: sys/kern/kern_sysctl.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sysctl.c,v
retrieving revision 1.320
diff -u -p -u -r1.320 kern_sysctl.c
--- sys/kern/kern_sysctl.c    11 Nov 2016 18:59:09 -0000    1.320
+++ sys/kern/kern_sysctl.c    4 Dec 2016 20:43:53 -0000
@@ -263,6 +263,7 @@ size_t disknameslen;
 struct diskstats *diskstats = NULL;
 size_t diskstatslen;
 int securelevel;
+int seeotheruids = 1; /* on by default */
 
 /*
  * kernel related system variables.
@@ -632,6 +633,13 @@ kern_sysctl(int *name, u_int namelen, vo
         dnsjackport = port;
         return 0;
     }
+    case KERN_SEEOTHERUIDS: {
+        if (securelevel > 0)
+            return (sysctl_rdint(oldp, oldlenp, newp,
+                seeotheruids));
+        return (sysctl_int(oldp, oldlenp, newp, newlen,
+            &seeotheruids));
+    }
     default:
         return (EOPNOTSUPP);
     }
@@ -1427,7 +1435,8 @@ sysctl_doproc(int *name, u_int namelen,
     int arg, buflen, doingzomb, elem_size, elem_count;
     int error, needed, op;
     int dothreads = 0;
-    int show_pointers;
+    int is_suser, show_pointers, show_otheruids;
+    uid_t euid;
 
     dp = where;
     buflen = where != NULL ? *sizep : 0;
@@ -1444,7 +1453,10 @@ sysctl_doproc(int *name, u_int namelen,
     dothreads = op & KERN_PROC_SHOW_THREADS;
     op &= ~KERN_PROC_SHOW_THREADS;
 
-    show_pointers = suser(curproc, 0) == 0;
+    is_suser = suser(curproc, 0) == 0;
+    show_pointers = is_suser;
+    show_otheruids = seeotheruids || is_suser;
+    euid = curproc->p_ucred->cr_uid;
 
     if (where != NULL)
         kproc = malloc(sizeof(*kproc), M_TEMP, M_WAITOK);
@@ -1461,6 +1473,9 @@ again:
          * Skip embryonic processes.
          */
         if (pr->ps_flags & PS_EMBRYO)
+            continue;
+
+        if (!show_otheruids && pr->ps_ucred->cr_uid != euid)
             continue;
 
         /*
Index: sys/sys/sysctl.h
===================================================================
RCS file: /cvs/src/sys/sys/sysctl.h,v
retrieving revision 1.170
diff -u -p -u -r1.170 sysctl.h
--- sys/sys/sysctl.h    7 Nov 2016 00:26:32 -0000    1.170
+++ sys/sys/sysctl.h    4 Dec 2016 20:43:55 -0000
@@ -184,7 +184,8 @@ struct ctlname {
 #define    KERN_GLOBAL_PTRACE    81    /* allow ptrace globally */
 #define    KERN_CONSBUFSIZE    82    /* int: console message buffer size */
 #define    KERN_CONSBUF        83    /* console message buffer */
-#define    KERN_MAXID        84    /* number of valid kern ids */
+#define    KERN_SEEOTHERUIDS    84    /* see other users' proceesses */
+#define    KERN_MAXID        85    /* number of valid kern ids */
 
 #define    CTL_KERN_NAMES { \
     { 0, 0 }, \
@@ -269,6 +270,9 @@ struct ctlname {
     { "proc_nobroadcastkill", CTLTYPE_NODE }, \
     { "proc_vmmap", CTLTYPE_NODE }, \
     { "global_ptrace", CTLTYPE_INT }, \
+    { "gap", 0 }, \
+    { "gap", 0 }, \
+    { "see_other_uids", CTLTYPE_INT }, \
 }
 
 /*

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