[binutils-gdb] PR22205, .debug_line file table NULL filename

[Alan Modra <amodra at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a54018b72d75abf2e74bf36016702da06399c1d9

commit a54018b72d75abf2e74bf36016702da06399c1d9
Author: Alan Modra <amodra@gmail.com>
Date:   Tue Sep 26 09:38:26 2017 +0930

    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:
---
 bfd/ChangeLog |  7 +++++++
 bfd/dwarf2.c  | 35 +++++++++++++----------------------
 2 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 5c4cc2b..78f95d1 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,12 @@
 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
 	* dwarf2.c (decode_line_info): Ensure line_ptr stays within
 	bounds in inner loop.
diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 2c45790..225b4a9 100644
--- 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 =