[PATCH] Increase the default RLIMIT_MEMLOCK

[Josselin Mouette <joss@debian.org>]

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Hi,

Currently, the default value for RLIMIT_MEMLOCK (defined in
include/linux/resource.h) is 32 KiB, because this value is enough for
GnuPG.

However this value is not enough for gnome-keyring-daemon, which will
store both SSH and GnuPG keys, plus user passwords for various kinds of
resources. Upstream authors recommend to provide a limit of at least 256
KiB for RLIMIT_MEMLOCK for the keys to remain securely in memory.

Given the amount of memory in current machines, I think 256 KiB is still
a very reasonable value. What do you think of increasing this default
value in the kernel?

Cheers,
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--- include/linux/resource.h.orig	2008-04-27 21:15:47.000000000 +0200
+++ include/linux/resource.h	2008-04-27 21:23:06.000000000 +0200
@@ -58,10 +58,11 @@
 #define _STK_LIM	(8*1024*1024)
 
 /*
- * GPG wants 32kB of mlocked memory, to make sure pass phrases
- * and other sensitive information are never written to disk.
+ * The biggest widespread mlocked memory consumer is 
+ * gnome-keyring-manager. It needs 256kB to make sure SSH/GPG 
+ * passphrases and network passwords are never written to disk.
  */
-#define MLOCK_LIMIT	(8 * PAGE_SIZE)
+#define MLOCK_LIMIT	(64 * PAGE_SIZE)
 
 /*
  * Due to binary compatibility, the actual resource numbers

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