[PATCH] uml: increase granularity of host capability checking

This change enables SKAS0/SKAS3 to work with all combinations of /proc/mm and
PTRACE_FAULTINFO being available or not.

Also it changes the initialization of proc_mm and ptrace_faultinfo slightly,
to ease forcing SKAS0 on a patched host.  Forcing UML to run without /proc/mm
or PTRACE_FAULTINFO by cmdline parameter can be implemented with a setup
resetting the related variable.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c
index cbabab104ac3..3d1b227226e6 100644
--- a/arch/um/kernel/skas/process_kern.c
+++ b/arch/um/kernel/skas/process_kern.c
@@ -129,7 +129,9 @@ int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp,
         return(0);
 }
 
-int new_mm(int from)
+extern void map_stub_pages(int fd, unsigned long code,
+                           unsigned long data, unsigned long stack);
+int new_mm(int from, unsigned long stack)
 {
         struct proc_mm_op copy;
         int n, fd;
@@ -148,6 +150,9 @@ int new_mm(int from)
                                "err = %d\n", -n);
         }
 
+        if(!ptrace_faultinfo)
+                map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack);
+
         return(fd);
 }