Security patch 3 of 3

This one removes singlestepping_tt() and singlestepping_skas() and
Inserts singlestepping() instead.
Now SKAS mode should be OK, with the exception of the vsyscall page.

I have tested in tt and skas mode.

Bodo

--- linux-2.6.9-rc2-orig/arch/um/kernel/skas/process.c	2004-10-01
15:34:49.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/skas/process.c	2004-10-01
18:23:35.481627322 +0200
 <at>  <at>  -185,10 +185,10  <at>  <at> 
 		local_using_sysemu = get_using_sysemu();

 		if (local_using_sysemu)
-			op = singlestepping_skas() ? PTRACE_SINGLESTEP :
+			op = singlestepping(NULL) ? PTRACE_SINGLESTEP :
 				PTRACE_SYSEMU;
 		else
-			op = singlestepping_skas() ? PTRACE_SINGLESTEP :
+			op = singlestepping(NULL) ? PTRACE_SINGLESTEP :
 				PTRACE_SYSCALL;

 		err = ptrace(op, pid, 0, 0);
--- linux-2.6.9-rc2-orig/arch/um/kernel/skas/include/skas.h
2004-10-01 15:34:49.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/skas/include/skas.h	2004-10-01
18:25:13.728391472 +0200
 <at>  <at>  -28,7 +28,6  <at>  <at> 
 extern int protect(int fd, unsigned long addr, unsigned long len, 
 		   int r, int w, int x, int must_succeed);
 extern void user_signal(int sig, union uml_pt_regs *regs);
-extern int singlestepping_skas(void);
 extern int new_mm(int from);
 extern void start_userspace(int cpu);

--- linux-2.6.9-rc2-orig/arch/um/kernel/skas/syscall_kern.c
2004-09-13 07:32:54.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/skas/syscall_kern.c	2004-10-01
18:28:35.139107179 +0200
 <at>  <at>  -4,6 +4,7  <at>  <at> 
  */

 #include "linux/sys.h"
+#include "linux/ptrace.h"
 #include "asm/errno.h"
 #include "asm/unistd.h"
 #include "asm/ptrace.h"
 <at>  <at>  -27,6 +28,12  <at>  <at> 
 		res = -ENOSYS;
 	else res = EXECUTE_SYSCALL(syscall, regs);

+	if(current->thread.singlestep_syscall){
+		current->thread.singlestep_syscall = 0;
+		current->ptrace &= ~PT_DTRACE;
+		force_sig(SIGTRAP, current);
+	}
+
 	return(res);
 }

--- linux-2.6.9-rc2-orig/arch/um/kernel/skas/process_kern.c
2004-10-01 15:34:49.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/skas/process_kern.c	2004-10-01
18:30:21.989449538 +0200
 <at>  <at>  -79,14 +79,6  <at>  <at> 

 late_initcall(make_proc_sysemu);

-int singlestepping_skas(void)
-{
-	int ret = current->ptrace & PT_DTRACE;
-
-	current->ptrace &= ~PT_DTRACE;
-	return(ret);
-}
-
 void *switch_to_skas(void *prev, void *next)
 {
 	struct task_struct *from, *to;
--- linux-2.6.9-rc2-orig/arch/um/kernel/tt/tracer.c	2004-09-29
14:49:59.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/tt/tracer.c	2004-10-01
18:33:30.732258690 +0200
 <at>  <at>  -367,7 +367,7  <at>  <at> 
 			}

 			if(tracing){
-				if(singlestepping_tt(task))
+				if(singlestepping(task))
 					cont_type = PTRACE_SINGLESTEP;
 				else cont_type = PTRACE_SYSCALL;
 			}
--- linux-2.6.9-rc2-orig/arch/um/kernel/tt/include/tt.h	2004-09-13
07:32:54.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/tt/include/tt.h	2004-10-01
18:34:01.584160234 +0200
 <at>  <at>  -24,7 +24,6  <at>  <at> 
 extern int set_user_mode(void *task);
 extern void set_tracing(void *t, int tracing);
 extern int is_tracing(void *task);
-extern int singlestepping_tt(void *t);
 extern void clear_singlestep(void *t);
 extern void syscall_handler(int sig, union uml_pt_regs *regs);
 extern void exit_kernel(int pid, void *task);
--- linux-2.6.9-rc2-orig/arch/um/kernel/tt/process_kern.c
2004-10-01 18:17:49.961726497 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/tt/process_kern.c	2004-10-01
18:36:17.124761361 +0200
 <at>  <at>  -524,15 +524,6  <at>  <at> 
 		      -err);
 }

-int singlestepping_tt(void *t)
-{
-	struct task_struct *task = t;
-
-	if(task->thread.singlestep_syscall)
-		return(0);
-	return(task->ptrace & PT_DTRACE);
-}
-
 void clear_singlestep(void *t)
 {
 	struct task_struct *task = t;
--- linux-2.6.9-rc2-orig/arch/um/kernel/process_kern.c	2004-09-29
14:49:59.000000000 +0200
+++ linux-2.6.9-rc2/arch/um/kernel/process_kern.c	2004-10-01
18:42:27.756512307 +0200
 <at>  <at>  -19,6 +19,7  <at>  <at> 
 #include "linux/capability.h"
 #include "linux/vmalloc.h"
 #include "linux/spinlock.h"
+#include "linux/ptrace.h"
 #include "asm/unistd.h"
 #include "asm/mman.h"
 #include "asm/segment.h"
 <at>  <at>  -400,6 +401,15  <at>  <at> 
 	return(current_thread->cpu);
 }

+int singlestepping(void * t)
+{
+	struct task_struct *task = t ? t : current;
+
+	if (task->thread.singlestep_syscall)
+		return(0);
+	return(task->ptrace & PT_DTRACE);
+}
+
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
  * Emacs will notice this stuff at the end of the file and
automatically

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