PR22205, .debug_line file table NULL filename

The PR22200 fuzzer testcase found one way to put NULLs into .debug_line
file tables.  PR22205 finds another.  This patch gives up on trying to
prevent NULL files in the file table and instead just copes with them.
Arguably, this is better than giving up and showing no info from
.debug_line.  I've also fixed a case where the fairly recent DWARF5
support in handling broken DWARG could result in uninitialized memory
reads, and made a small tidy.

	PR 22205
	* dwarf2.c (concat_filename): Return "<unknown>" on NULL filename.
	(read_formatted_entries): Init "fe".
	(decode_line_info <DW_LNE_define_file>): Use line_info_add_file_name.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 5c4cc2bccd10ee609a660c45e2ff24df6762f78f..78f95d102c4b4e7320aef589f5f0e1cd81fc3acf 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2017-09-26  Alan Modra  <amodra@gmail.com>
+
+       PR 22205
+       * dwarf2.c (concat_filename): Return "<unknown>" on NULL filename.
+       (read_formatted_entries): Init "fe".
+       (decode_line_info <DW_LNE_define_file>): Use line_info_add_file_name.
+
 2017-09-26  Alan Modra  <amodra@gmail.com>
 
        PR 22204

diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 2c457909356b4a4d2f44ca117cbca7d3e5c42980..225b4a9e54e80bff2a31ccb46273409a17f6356b 100644 (file)
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -1597,6 +1597,8 @@ concat_filename (struct line_info_table *table, unsigned int file)
     }
 
   filename = table->files[file - 1].name;
+  if (filename == NULL)
+    return strdup ("<unknown>");
 
   if (!IS_ABSOLUTE_PATH (filename))
     {
@@ -1945,6 +1947,7 @@ read_formatted_entries (struct comp_unit *unit, bfd_byte **bufp,
       bfd_byte *format = format_header_data;
       struct fileinfo fe;
 
+      memset (&fe, 0, sizeof fe);
       for (formati = 0; formati < format_count; formati++)
        {
          bfd_vma content_type, form;
@@ -2268,6 +2271,7 @@ decode_line_info (struct comp_unit *unit, struct dwarf2_debug *stash)
       unsigned int discriminator = 0;
       int is_stmt = lh.default_is_stmt;
       int end_sequence = 0;
+      unsigned int dir, xtime, size;
       /* eraxxon@alumni.rice.edu: Against the DWARF2 specs, some
         compilers generate address sequences that are wildly out of
         order using DW_LNE_set_address (e.g. Intel C++ 6.0 compiler
@@ -2342,31 +2346,18 @@ decode_line_info (struct comp_unit *unit, struct dwarf2_debug *stash)
                case DW_LNE_define_file:
                  cur_file = read_string (abfd, line_ptr, line_end, &bytes_read);
                  line_ptr += bytes_read;
-                 if ((table->num_files % FILE_ALLOC_CHUNK) == 0)
-                   {
-                     struct fileinfo *tmp;
-
-                     amt = table->num_files + FILE_ALLOC_CHUNK;
-                     amt *= sizeof (struct fileinfo);
-                     tmp = (struct fileinfo *) bfd_realloc (table->files, amt);
-                     if (tmp == NULL)
-                       goto line_fail;
-                     table->files = tmp;
-                   }
-                 table->files[table->num_files].name = cur_file;
-                 table->files[table->num_files].dir =
-                   _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
-                                          FALSE, line_end);
+                 dir = _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
+                                              FALSE, line_end);
                  line_ptr += bytes_read;
-                 table->files[table->num_files].time =
-                   _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
-                                          FALSE, line_end);
+                 xtime = _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
+                                                FALSE, line_end);
                  line_ptr += bytes_read;
-                 table->files[table->num_files].size =
-                   _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
-                                          FALSE, line_end);
+                 size = _bfd_safe_read_leb128 (abfd, line_ptr, &bytes_read,
+                                               FALSE, line_end);
                  line_ptr += bytes_read;
-                 table->num_files++;
+                 if (!line_info_add_file_name (table, cur_file, dir,
+                                               xtime, size))
+                   goto line_fail;
                  break;
                case DW_LNE_set_discriminator:
                  discriminator =