libdwfl: Fix assert and set in.d_size in dwfl_link_map_report.

When reading the phdrs from a core file segment fails we would try to read
them from the exec. This fallback path contained a faulty assert that the
requested size of the phdrs was still setup. But the core file reading
callback might have reset the d_size value to zero on error. So explicitly
set the number of bytes we want to read again instead of asserting the size.

https://bugzilla.redhat.com/show_bug.cgi?id=1365812

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

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index bdfc92f..3332db7 100644 (file)
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,7 @@
+2016-08-12  Mark Wielaard  <mjw@redhat.com>
+
+       * link_map.c (dwfl_link_map_report): Fix assert, set in.d_size.
+
 2016-04-14  Mark Wielaard  <mjw@redhat.com>
 
        * dwfl_module_getsrc_file.c (dwfl_module_getsrc_file): Free match

diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c
index 28d7382..794668f 100644 (file)
--- a/libdwfl/link_map.c
+++ b/libdwfl/link_map.c
@@ -1,5 +1,5 @@
 /* Report modules by examining dynamic linker data structures.
-   Copyright (C) 2008-2015 Red Hat, Inc.
+   Copyright (C) 2008-2016 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -843,7 +843,10 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
                }
              off_t off = ehdr->e_phoff;
              assert (in.d_buf == NULL);
-             assert (in.d_size == phnum * phent);
+             /* Note this in the !in_ok path.  That means memory_callback
+                failed.  But the callback might still have reset the d_size
+                value (to zero).  So explicitly set it here again.  */
+             in.d_size = phnum * phent;
              in.d_buf = malloc (in.d_size);
              if (unlikely (in.d_buf == NULL))
                {