File backtrace-powerpc.patch of Package glibc.34926

From d93769405996dfc11d216ddbe415946617b5a494 Mon Sep 17 00:00:00 2001
From: Andreas Schwab <schwab@suse.de>
Date: Mon, 20 Jan 2020 17:01:50 +0100
Subject: [PATCH] Fix array overflow in backtrace on PowerPC (bug 25423)

When unwinding through a signal frame the backtrace function on PowerPC
didn't check array bounds when storing the frame address.  Fixes commit
d400dcac5e ("PowerPC: fix backtrace to handle signal trampolines").
---
 debug/tst-backtrace5.c                | 12 ++++++++++++
 sysdeps/powerpc/powerpc32/backtrace.c |  2 ++
 sysdeps/powerpc/powerpc64/backtrace.c |  2 ++
 3 files changed, 16 insertions(+)

Index: glibc-2.22/debug/tst-backtrace5.c
===================================================================
--- glibc-2.22.orig/debug/tst-backtrace5.c
+++ glibc-2.22/debug/tst-backtrace5.c
@@ -92,6 +92,18 @@ handle_signal (int signum)
       }
   /* Symbol names are not available for static functions, so we do not
      check do_test.  */
+
+  /* Check that backtrace does not return more than what fits in the array
+     (bug 25423).  */
+  for (int j = 0; j < NUM_FUNCTIONS; j++)
+    {
+      n = backtrace (addresses, j);
+      if (n > j)
+	{
+	  FAIL ();
+	  return;
+	}
+    }
 }
 
 NO_INLINE int
Index: glibc-2.22/sysdeps/powerpc/powerpc32/backtrace.c
===================================================================
--- glibc-2.22.orig/sysdeps/powerpc/powerpc32/backtrace.c
+++ glibc-2.22/sysdeps/powerpc/powerpc32/backtrace.c
@@ -113,7 +113,11 @@ __backtrace (void **array, int size)
           gregset = &sigframe->uc.uc_mcontext.uc_regs->gregs;
         }
       if (gregset)
-	array[++count] = (void*)((*gregset)[PT_NIP]);
+	{
+	  if (count + 1 == size)
+	    break;
+	  array[++count] = (void*)((*gregset)[PT_NIP]);
+	}
     }
 
   /* It's possible the second-last stack frame can't return
Index: glibc-2.22/sysdeps/powerpc/powerpc64/backtrace.c
===================================================================
--- glibc-2.22.orig/sysdeps/powerpc/powerpc64/backtrace.c
+++ glibc-2.22/sysdeps/powerpc/powerpc64/backtrace.c
@@ -85,6 +85,8 @@ __backtrace (void **array, int size)
       if (is_sigtramp_address ((unsigned long)current->return_address))
         {
 	  struct signal_frame_64 *sigframe = (struct signal_frame_64*) current;
+	  if (count + 1 == size)
+	    break;
           array[++count] = (void*)sigframe->uc.uc_mcontext.gp_regs[PT_NIP];
 	}
     }