[PATCH] Add TAINT_USER and ability to set taint flags from userspace

Allow taint flags to be set from userspace by writing to
/proc/sys/kernel/tainted, and add a new taint flag, TAINT_USER, to be used
when userspace has potentially done something dangerous that might
compromise the kernel.  This will allow support personnel to ask further
questions about what may have caused the user taint flag to have been set.

For example, they might examine the logs of the realtime JVM to see if the
Java program has used the really silly, stupid, dangerous, and
completely-non-portable direct access to physical memory feature which MUST
be implemented according to the Real-Time Specification for Java (RTSJ).
Sigh.  What were those silly people at Sun thinking?

[akpm@osdl.org: build fix]
[bunk@stusta.de: cleanup]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/panic.c b/kernel/panic.c
index 525e365f7239..623d1828259a 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -150,6 +150,7 @@ EXPORT_SYMBOL(panic);
  *  'R' - User forced a module unload.
  *  'M' - Machine had a machine check experience.
  *  'B' - System has hit bad_page.
+ *  'U' - Userspace-defined naughtiness.
  *
  *      The string is overwritten by the next call to print_taint().
  */
@@ -158,13 +159,14 @@ const char *print_tainted(void)
 {
         static char buf[20];
         if (tainted) {
-                snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c",
+                snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c",
                         tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
                         tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
                         tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
                         tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
                         tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
-                        tainted & TAINT_BAD_PAGE ? 'B' : ' ');
+                        tainted & TAINT_BAD_PAGE ? 'B' : ' ',
+                        tainted & TAINT_USER ? 'U' : ' ');
         }
         else
                 snprintf(buf, sizeof(buf), "Not tainted");