1 files changed, 41 insertions, 19 deletions

diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 1a2be6e639b5..f468a5b44508 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -171,6 +171,9 @@ long arch_ptrace(struct task_struct *child, long request,
 		if ((addr & (sizeof(unsigned long)-1)) ||
 		     addr >= sizeof(struct pt_regs))
 			break;
+		if (addr == PT_IAOQ0 || addr == PT_IAOQ1) {
+			data |= 3; /* ensure userspace privilege */
+		}
 		if ((addr >= PT_GR1 && addr <= PT_GR31) ||
 				addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
 				(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
@@ -232,16 +235,18 @@ long arch_ptrace(struct task_struct *child, long request,
 
 static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
 {
-	if (offset < 0)
-		return sizeof(struct pt_regs);
-	else if (offset <= 32*4)	/* gr[0..31] */
-		return offset * 2 + 4;
-	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
-		return offset + 32*4;
-	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
-		return offset * 2 + 4 - 32*8;
+	compat_ulong_t pos;
+
+	if (offset < 32*4)	/* gr[0..31] */
+		pos = offset * 2 + 4;
+	else if (offset < 32*4+32*8)	/* fr[0] ... fr[31] */
+		pos = (offset - 32*4) + PT_FR0;
+	else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */
+		pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4;
 	else
-		return sizeof(struct pt_regs);
+		pos = sizeof(struct pt_regs);
+
+	return pos;
 }
 
 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
@@ -285,9 +290,12 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 			addr = translate_usr_offset(addr);
 			if (addr >= sizeof(struct pt_regs))
 				break;
+			if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) {
+				data |= 3; /* ensure userspace privilege */
+			}
 			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
 				/* Special case, fp regs are 64 bits anyway */
-				*(__u64 *) ((char *) task_regs(child) + addr) = data;
+				*(__u32 *) ((char *) task_regs(child) + addr) = data;
 				ret = 0;
 			}
 			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
@@ -312,15 +320,29 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 long do_syscall_trace_enter(struct pt_regs *regs)
 {
-	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
-	    tracehook_report_syscall_entry(regs)) {
+	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+		int rc = tracehook_report_syscall_entry(regs);
+
 		/*
-		 * Tracing decided this syscall should not happen or the
-		 * debugger stored an invalid system call number. Skip
-		 * the system call and the system call restart handling.
+		 * As tracesys_next does not set %r28 to -ENOSYS
+		 * when %r20 is set to -1, initialize it here.
 		 */
-		regs->gr[20] = -1UL;
-		goto out;
+		regs->gr[28] = -ENOSYS;
+
+		if (rc) {
+			/*
+			 * A nonzero return code from
+			 * tracehook_report_syscall_entry() tells us
+			 * to prevent the syscall execution.  Skip
+			 * the syscall call and the syscall restart handling.
+			 *
+			 * Note that the tracer may also just change
+			 * regs->gr[20] to an invalid syscall number,
+			 * that is handled by tracesys_next.
+			 */
+			regs->gr[20] = -1UL;
+			return -1;
+		}
 	}
 
 	/* Do the secure computing check after ptrace. */
@@ -344,7 +366,6 @@ long do_syscall_trace_enter(struct pt_regs *regs)
 			regs->gr[24] & 0xffffffff,
 			regs->gr[23] & 0xffffffff);
 
-out:
 	/*
 	 * Sign extend the syscall number to 64bit since it may have been
 	 * modified by a compat ptrace call
@@ -487,7 +508,8 @@ static void set_reg(struct pt_regs *regs, int num, unsigned long val)
 			return;
 	case RI(iaoq[0]):
 	case RI(iaoq[1]):
-			regs->iaoq[num - RI(iaoq[0])] = val;
+			/* set 2 lowest bits to ensure userspace privilege: */
+			regs->iaoq[num - RI(iaoq[0])] = val | 3;
 			return;
 	case RI(sar):	regs->sar = val;
 			return;