1 files changed, 25 insertions, 19 deletions

diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c
index 5b20c2874d51..e92e40527d6d 100644
--- a/arch/tile/kernel/ptrace.c
+++ b/arch/tile/kernel/ptrace.c
@@ -45,19 +45,20 @@ void ptrace_disable(struct task_struct *child)
         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 }
 
-long arch_ptrace(struct task_struct *child, long request, long addr, long data)
+long arch_ptrace(struct task_struct *child, long request,
+                 unsigned long addr, unsigned long data)
 {
         unsigned long __user *datap = (long __user __force *)data;
         unsigned long tmp;
-        int i;
         long ret = -EIO;
-        unsigned long *childregs;
         char *childreg;
+        struct pt_regs copyregs;
+        int ex1_offset;
 
         switch (request) {
 
         case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
-                if (addr < 0 || addr >= PTREGS_SIZE)
+                if (addr >= PTREGS_SIZE)
                         break;
                 childreg = (char *)task_pt_regs(child) + addr;
 #ifdef CONFIG_COMPAT
@@ -76,9 +77,19 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 break;
 
         case PTRACE_POKEUSR:  /* Write register in pt_regs. */
-                if (addr < 0 || addr >= PTREGS_SIZE)
+                if (addr >= PTREGS_SIZE)
                         break;
                 childreg = (char *)task_pt_regs(child) + addr;
+
+                /* Guard against overwrites of the privilege level. */
+                ex1_offset = PTREGS_OFFSET_EX1;
+#if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)
+                if (is_compat_task())   /* point at low word */
+                        ex1_offset += sizeof(compat_long_t);
+#endif
+                if (addr == ex1_offset)
+                        data = PL_ICS_EX1(USER_PL, EX1_ICS(data));
+
 #ifdef CONFIG_COMPAT
                 if (is_compat_task()) {
                         if (addr & (sizeof(compat_long_t)-1))
@@ -95,24 +106,19 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                 break;
 
         case PTRACE_GETREGS:  /* Get all registers from the child. */
-                if (!access_ok(VERIFY_WRITE, datap, PTREGS_SIZE))
-                        break;
-                childregs = (long *)task_pt_regs(child);
-                for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) {
-                        ret = __put_user(childregs[i], &datap[i]);
-                        if (ret != 0)
-                                break;
+                if (copy_to_user(datap, task_pt_regs(child),
+                                 sizeof(struct pt_regs)) == 0) {
+                        ret = 0;
                 }
                 break;
 
         case PTRACE_SETREGS:  /* Set all registers in the child. */
-                if (!access_ok(VERIFY_READ, datap, PTREGS_SIZE))
-                        break;
-                childregs = (long *)task_pt_regs(child);
-                for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) {
-                        ret = __get_user(childregs[i], &datap[i]);
-                        if (ret != 0)
-                                break;
+                if (copy_from_user(&copyregs, datap,
+                                   sizeof(struct pt_regs)) == 0) {
+                        copyregs.ex1 =
+                                PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));
+                        *task_pt_regs(child) = copyregs;
+                        ret = 0;
                 }
                 break;