fix some minor bugs:

bug0 (user entry encrypted with empty key and decrypted with different one - uninitialized authkey used)
----------------------------------------
% cd 
% rm -f keys
% auth/keyfs -p keys
% cd /mnt/keys
% mkdir user
Password: <something>
keyfs: warning: bad status in key file
1 keys read

bug1 (user entries encrypted with different keys - no difference exists between empty and uninitialized authkey)
----------------------------------------
% cd 
% echo -n > keys
% auth/keyfs -p keys
% cd /mnt/keys
% mkdir user
Password: <enter>
1 keys read
% mkdir user2
Password: <something>
keyfs: warning: bad status in key file
keyfs: warning: bad status in key file
2 keys read

bug2 (suicide on invalid status string)
----------------------------------------
% cd 
% echo -n > keys
% auth/keyfs -p keys
Password: 
0 keys read
% cd /mnt/keys
% mkdir user
1 keys read
% cd user
% echo die, babe > status
keyfs 2701: suicide: sys: trap: fault read addr=0x0 pc=0x00003986

bug3 (walk to ".." from user directory not implemented)
----------------------------------------
% cd
% auth/keyfs -p keys
Password: 
1 keys read
% cd /mnt/keys/user
% cd ..
Can't cd ..: '..' file not found

bug4 (Remove does not clunk fids in some cases)
----------------------------------------
% pwd
/mnt/keys/user
% rm key key
rm: key: permission denied
rm: key: 'key' fid in use

bug5 (memory leak)
----------------------------------------
allocated at installuser: 'u->name = strdup(name);', Wstat
leaked at Clunk

Notes:
Mon Feb 7 23:08:48 EST 2005 rsc
    I applied this.  I agree with all your changes,
    but I don't understand why they would fix the
    suicide on bogus status write bug.  
    What am I missing?
    
    Thanks.
    Russ

Mon Feb 7 23:18:04 EST 2005 rsc
    By the way, thanks for sending such excellent bug descriptions
    with the patches.
    


Reference: /n/sources/patch/applied/keyfs
Date: Tue Feb  8 05:09:25 CET 2005
Reviewed-by: rsc

--- /sys/src/cmd/auth/keyfs.c	Tue Feb  8 05:09:25 2005
+++ /sys/src/cmd/auth/keyfs.c	Tue Feb  8 05:09:24 2005
@@ -31,7 +31,6 @@
 enum{
 	Sok,
 	Sdisabled,
-	Stempdisabled,
 	Smax,
 };
 
@@ -149,6 +148,13 @@
 	if(pipe(p) < 0)
 		error("can't make pipe: %r");
 
+	if(usepass) {
+		getpass(authkey, nil, 0, 0);
+	} else {
+		if(!getauthkey(authkey))
+			print("keyfs: warning: can't read /dev/key\n");
+	}
+
 	switch(rfork(RFPROC|RFNAMEG|RFNOTEG|RFNOWAIT|RFENVG|RFFDG)){
 	case 0:
 		close(p[0]);
@@ -252,6 +258,11 @@
 				break;
 
 			case Quser:
+				if(strcmp(name, "..") == 0) {
+					qtype = Qroot;
+					user = 0;
+					goto Accept;
+				}
 				max = Qmax;
 				for(j = Quser + 1; j < Qmax; j++)
 					if(strcmp(name, qinfo[j]) == 0){
@@ -298,8 +309,10 @@
 Clunk(Fid *f)
 {
 	f->busy = 0;
-	if(f->user && --f->user->ref == 0 && f->user->removed)
+	if(f->user && --f->user->ref == 0 && f->user->removed) {
+		free(f->user->name);
 		free(f->user);
+	}
 	f->user = 0;
 	return 0;
 }
@@ -559,8 +572,10 @@
 		f->user->warnings = 0;
 	else if(f->qtype == Quser)
 		removeuser(f->user);
-	else
+	else {
+		Clunk(f);
 		return "permission denied";
+	}
 	Clunk(f);
 	writeusers();
 	return 0;
@@ -765,15 +780,6 @@
 	uchar *p, *buf, *ep;
 	User *u;
 	Dir *d;
-
-	if(usepass) {
-		if(*authkey == 0)
-			getpass(authkey, nil, 0, 0);
-	} else {
-		if(!getauthkey(authkey))
-			print("keyfs: warning: can't read /dev/key\n");
-	}
-
 
 	/* read file into an array */
 	fd = open(userkeys, OREAD);