[PATCH] fix keysize/keybits handling of mount

[Marc Mutz <Marc@Mutz.com>]

Hi Astor!

The -k resp. parameter to mount was not working (the 'k' was missing
from the list of option characters in getopt). I removed that switch. It
should really be something you can stuff into /etc/fstab and therefore
it needs to be an option to be supplied via '-o'. So now there is a
keysize= option you can put into the options column of fstab(5) or
specify on the command line via '-o'. Additionally, it error()'s if
someone gives the keysize option w/o giving the encryption option, too.
Please check that if clause carfully. I don't know what I was doing
there... 

This patch is completely untested, I did not even check if it compiles,
but I modelled this option along the offset option, so there should be
no big mistakes.

It's relative to a util-linux2.10r, patched with the util-linux patch
from 2.2.18.4pre1.

Please consider applying (after testing :-).

Marc

-- 
Marc Mutz <Marc@Mutz.com>     http://EncryptionHOWTO.sourceforge.net/
University of Bielefeld, Dep. of Mathematics / Dep. of Physics

PGP-keyID's:   0xd46ce9ab (RSA), 0x7ae55b9e (DSS/DH)
--- util-linux-2.10r/mount/mount.c.orig	Mon Jan 15 18:59:53 2001
+++ util-linux-2.10r/mount/mount.c	Wed Jan 31 19:19:00 2001
@@ -113,9 +113,6 @@
 /* Contains the fd no. to read the passphrase from, if any */
 static int pfd = -1;
 
-/* Contains the preferred keysize in bits we want to use */
-static int keysz = 0;
-
 /* Map from -o and fstab option strings to the flag argument to mount(2).  */
 struct opt_map {
   const char *opt;		/* option name */
@@ -192,7 +189,7 @@
 };
 
 static char *opt_loopdev, *opt_vfstype, *opt_offset, *opt_encryption,
-  *opt_speed;
+  *opt_keysize, *opt_speed;
 
 static struct string_opt_map {
   char *tag;
@@ -203,6 +200,7 @@
   { "vfs=",	1, &opt_vfstype },
   { "offset=",	0, &opt_offset },
   { "encryption=", 0, &opt_encryption },
+  { "keysize=", 0, &opt_keysize },
   { "speed=", 0, &opt_speed },
   { NULL, 0, NULL }
 };
@@ -536,7 +534,7 @@
 static int
 loop_check(char **spec, char **type, int *flags,
 	   int *loop, char **loopdev, char **loopfile) {
-  int looptype, offset;
+  int looptype, offset, keysize;
 
   /*
    * In the case of a loop mount, either type is of the form lo@/dev/loop5
@@ -561,6 +559,9 @@
       *type = opt_vfstype;
   }
 
+  if (*opt_keysize && !*opt_encryption)
+    error(_("mount: you cannot specify a keysize without specifying encryption"));
+
   *loop = ((*flags & MS_LOOP) || *loopdev || opt_offset || opt_encryption);
   *loopfile = *spec;
 
@@ -579,8 +580,9 @@
       if (verbose)
 	printf(_("mount: going to use the loop device %s\n"), *loopdev);
       offset = opt_offset ? strtoul(opt_offset, NULL, 0) : 0;
+      keysize = opt_keysize ? strtoul(opt_keysize, NULL, 0) : 0;
       if (set_loop (*loopdev, *loopfile, offset, opt_encryption, pfd, 
-		    keysz, &loopro)) {
+		    keysize, &loopro)) {
 	if (verbose)
 	  printf(_("mount: failed setting up loop device\n"));
 	return EX_FAIL;
@@ -1294,7 +1296,6 @@
 	{ "rw", 0, 0, 'w' },
 	{ "options", 1, 0, 'o' },
 	{ "pass-fd", 1, 0, 'p' },
-	{ "keybits", 1, 0, 'k' },
 	{ "types", 1, 0, 't' },
 	{ "bind", 0, 0, 128 },
 	{ "replace", 0, 0, 129 },
@@ -1341,7 +1342,6 @@
 	char *options = NULL, *spec, *node;
 	char *volumelabel = NULL;
 	char *passfd = NULL;
-	char *keysize = NULL;
 	char *uuid = NULL;
 	string_list types = NULL;
 	struct mntentchn *mc;
@@ -1377,9 +1377,6 @@
 		case 'h':		/* help */
 			usage (stdout, 0);
 			break;
-		case 'k':
-			keysize = optarg;
-			break;
 		case 'l':
 			list_with_volumelabel = 1;
 			break;
@@ -1485,8 +1482,6 @@
 
 	if (passfd && sscanf(passfd,"%d",&pfd) != 1)
 	        die (EX_USAGE, _("mount: argument to --pass-fd or -p must be a number"));
-	if (keysize && sscanf(keysize,"%d",&keysz) != 1)
-	        die (EX_USAGE, _("mount: argument to --keybits or -k must be a number"));
 
 	switch (argc+specseen) {
 	case 0: