From: Mark Wielaard <mjw@redhat.com>
Date: Tue, 1 Dec 2015 23:21:07 +0000 (+0100)
Subject: libdw: Don't use a FDE if it doesn't actually cover a real code range.
X-Git-Tag: elfutils-0.165~34
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e04da0e6bab6c6cca2d6e1657d18666f50d2ecfa;p=thirdparty%2Felfutils.git

libdw: Don't use a FDE if it doesn't actually cover a real code range.

If the FDE end <= start then it doesn't actually cover a valid code range.
Don't use and cache such FDEs (it will cause memory leaks if there is
another FDE that has the same start address and a valid code range).

Such FDEs have been seen in the backtrace.ppc.exec testfile.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
---

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index b176ade6f..738e2236d 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,8 @@
+2015-12-01  Mark Wielaard  <mjw@redhat.com>
+
+	* fde.c (intern_fde): Don't intern an fde that doesn't cover a
+	valid code range.
+
 2015-12-01  Mark Wielaard  <mjw@redhat.com>
 
 	* dwarf_end.c (dwarf_end): Call cu_free on fake_loc_cu if it exists.
diff --git a/libdw/fde.c b/libdw/fde.c
index c8475f3e6..2a59d3e12 100644
--- a/libdw/fde.c
+++ b/libdw/fde.c
@@ -90,6 +90,13 @@ intern_fde (Dwarf_CFI *cache, const Dwarf_FDE *entry)
     }
   fde->end += fde->start;
 
+  /* Make sure the fde actually covers a real code range.  */
+  if (fde->start >= fde->end)
+    {
+      free (fde);
+      return (void *) -1;
+    }
+
   fde->cie = cie;
 
   if (cie->sized_augmentation_data)