nm: Don't leak duplicate Dwarf local names.

Badly formed DWARF can have duplicate local names. In which case we do
want to detect those so we don't leak the memory.

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

diff --git a/src/ChangeLog b/src/ChangeLog
index be7768f..ffc1b29 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2015-12-02  Mark Wielaard  <mjw@redhat.com>
 
+       * nm.c (get_local_names): Check for duplicates in local_root tree.
+
+2015-12-02  Mark Wielaard  <mjw@redhat.com>
+
        * unstrip.c (struct data_list): New.
        (new_data_list): Likewise.
        (record_new_data): Likewise.

diff --git a/src/nm.c b/src/nm.c
index 15d9da4..69623fe 100644 (file)
--- a/src/nm.c
+++ b/src/nm.c
@@ -708,11 +708,16 @@ get_local_names (Dwarf *dbg)
            newp->lowpc = lowpc;
            newp->highpc = highpc;
 
-           /* Since we cannot deallocate individual memory we do not test
-              for duplicates in the tree.  This should not happen anyway.  */
-           if (tsearch (newp, &local_root, local_compare) == NULL)
-             error (EXIT_FAILURE, errno,
-                    gettext ("cannot create search tree"));
+          /* Check whether a similar local_name is already in the
+             cache.  That should not happen.  But if it does, we
+             don't want to leak memory.  */
+           struct local_name **tres = tsearch (newp, &local_root,
+                                               local_compare);
+           if (tres == NULL)
+              error (EXIT_FAILURE, errno,
+                     gettext ("cannot create search tree"));
+           else if (*tres != newp)
+             free (newp);
          }
        while (dwarf_siblingof (die, die) == 0);
     }