From: Nick Clifton <nickc@redhat.com>
Date: Thu, 3 Sep 2020 14:52:53 +0000 (+0100)
Subject: Import a patch from mainline to fix a spurious overflow error when decoding negative... 
X-Git-Tag: binutils-2_35_1~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1f1ded87c9250deb986067eac6d53663f3f69e09;p=thirdparty%2Fbinutils-gdb.git

Import a patch from mainline to fix a spurious overflow error when decoding negative LEB128 values.

	PR 26548
	* dwarf.c (read_leb128): When checking for overflow of a signed
	read, use a signed shift.
---

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 2e7fecee8ca..0ccacc63e5d 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,12 @@
+2020-09-03  Nick Clifton  <nickc@redhat.com>
+
+	Import from mainline:
+	2020-08-28  Nick Clifton  <nickc@redhat.com>
+
+	PR 26548
+	* dwarf.c (read_leb128): When checking for overflow of a signed
+	read, use a signed shift.
+
 2020-08-25  Nick Clifton  <nickc@redhat.com>
 
 	Backport from the mainline:
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index bdabd9c4baa..cc13fe067f0 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -345,20 +345,34 @@ read_leb128 (unsigned char *data,
   while (data < end)
     {
       unsigned char byte = *data++;
+      bfd_boolean cont = (byte & 0x80) ? TRUE : FALSE;
+
+      byte &= 0x7f;
       num_read++;
 
       if (shift < sizeof (result) * 8)
 	{
-	  result |= ((dwarf_vma) (byte & 0x7f)) << shift;
-	  if ((result >> shift) != (byte & 0x7f))
-	    /* Overflow.  */
-	    status |= 2;
+	  result |= ((dwarf_vma) byte) << shift;
+	  if (sign)
+	    {
+	      if ((((dwarf_signed_vma) result >> shift) & 0x7f) != byte)
+		/* Overflow.  */
+		status |= 2;
+	    }
+	  else if ((result >> shift) != byte)
+	    {
+	      /* Overflow.  */
+	      status |= 2;
+	    }
+
 	  shift += 7;
 	}
-      else if ((byte & 0x7f) != 0)
-	status |= 2;
+      else if (byte != 0)
+	{
+	  status |= 2;
+	}
 
-      if ((byte & 0x80) == 0)
+      if (!cont)
 	{
 	  status &= ~1;
 	  if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40))