From: Nick Clifton <nickc@redhat.com>
Date: Wed, 28 Feb 2018 10:13:54 +0000 (+0000)
Subject: Fix potential integer overflow when reading corrupt dwarf1 debug information.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=eef104664efb52965d85a28bc3fc7c77e52e48e2;p=binutils-gdb.git

Fix potential integer overflow when reading corrupt dwarf1 debug information.

	PR 22894
	* dwarf1.c (parse_die): Check the length of form blocks before
	advancing the data pointer.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 446b978a7a8..76a6499f6a2 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2018-02-28  Nick Clifton  <nickc@redhat.com>
+
+	PR 22894
+	* dwarf1.c (parse_die): Check the length of form blocks before
+	advancing the data pointer.
+
 2018-02-28  Alan Modra  <amodra@gmail.com>
 
 	PR 22887
diff --git a/bfd/dwarf1.c b/bfd/dwarf1.c
index 71bc57bfdf8..f272ea83115 100644
--- a/bfd/dwarf1.c
+++ b/bfd/dwarf1.c
@@ -213,6 +213,7 @@ parse_die (bfd *	     abfd,
   /* Then the attributes.  */
   while (xptr + 2 <= aDiePtrEnd)
     {
+      unsigned int   block_len;
       unsigned short attr;
 
       /* Parse the attribute based on its form.  This section
@@ -255,12 +256,24 @@ parse_die (bfd *	     abfd,
 	  break;
 	case FORM_BLOCK2:
 	  if (xptr + 2 <= aDiePtrEnd)
-	    xptr += bfd_get_16 (abfd, xptr);
+	    {
+	      block_len = bfd_get_16 (abfd, xptr);
+	      if (xptr + block_len > aDiePtrEnd
+		  || xptr + block_len < xptr)
+		return FALSE;
+	      xptr += block_len;
+	    }
 	  xptr += 2;
 	  break;
 	case FORM_BLOCK4:
 	  if (xptr + 4 <= aDiePtrEnd)
-	    xptr += bfd_get_32 (abfd, xptr);
+	    {
+	      block_len = bfd_get_32 (abfd, xptr);
+	      if (xptr + block_len > aDiePtrEnd
+		  || xptr + block_len < xptr)
+		return FALSE;
+	      xptr += block_len;
+	    }
 	  xptr += 4;
 	  break;
 	case FORM_STRING: