[binutils-gdb] readelf info leaks from one object to the next

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=066f8fbede55e781c6241c445e0940f8368d0ef9

commit 066f8fbede55e781c6241c445e0940f8368d0ef9
Author: Alan Modra <amodra@gmail.com>
Date:   Fri Jun 11 12:49:02 2021 +0930

    readelf info leaks from one object to the next
    
    A number of filedata entries were not cleared.  Make sure they are
    all cleared out, except the ones needed for archive handling.
    
            * readelf.c (struct filedata): Move archive_file_offset and
            archive_file_size earlier.
            (free_filedata): Clear using memset.

Diff:
---
 binutils/ChangeLog |  6 ++++++
 binutils/readelf.c | 30 +++++-------------------------
 2 files changed, 11 insertions(+), 25 deletions(-)

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index bd91a3911d2..e84f5d36dec 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,9 @@
+2021-06-11  Alan Modra  <amodra@gmail.com>
+
+	* readelf.c (struct filedata): Move archive_file_offset and
+	archive_file_size earlier.
+	(free_filedata): Clear using memset.
+
 2021-06-11  Alan Modra  <amodra@gmail.com>
 
 	* readelf.c (GET_ELF_SYMBOLS): Delete.  Replace with..
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 52d5302d07b..1456c03a073 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -263,12 +263,13 @@ typedef struct filedata
   FILE *               handle;
   bfd_size_type        file_size;
   Elf_Internal_Ehdr    file_header;
+  unsigned long        archive_file_offset;
+  unsigned long        archive_file_size;
+  /* Everything below this point is cleared out by free_filedata.  */
   Elf_Internal_Shdr *  section_headers;
   Elf_Internal_Phdr *  program_headers;
   char *               string_table;
   unsigned long        string_table_length;
-  unsigned long        archive_file_offset;
-  unsigned long        archive_file_size;
   unsigned long        dynamic_addr;
   bfd_size_type        dynamic_size;
   size_t               dynamic_nent;
@@ -21191,35 +21192,14 @@ static void
 free_filedata (Filedata *filedata)
 {
   free (filedata->program_interpreter);
-  filedata->program_interpreter = NULL;
-
   free (filedata->program_headers);
-  filedata->program_headers = NULL;
-
   free (filedata->section_headers);
-  filedata->section_headers = NULL;
-
   free (filedata->string_table);
-  filedata->string_table = NULL;
-  filedata->string_table_length = 0;
-
   free (filedata->dump.dump_sects);
-  filedata->dump.dump_sects = NULL;
-  filedata->dump.num_dump_sects = 0;
-
   free (filedata->dynamic_strings);
-  filedata->dynamic_strings = NULL;
-  filedata->dynamic_strings_length = 0;
-
   free (filedata->dynamic_symbols);
-  filedata->dynamic_symbols = NULL;
-  filedata->num_dynamic_syms = 0;
-
   free (filedata->dynamic_syminfo);
-  filedata->dynamic_syminfo = NULL;
-
   free (filedata->dynamic_section);
-  filedata->dynamic_section = NULL;
 
   while (filedata->symtab_shndx_list != NULL)
     {
@@ -21229,7 +21209,6 @@ free_filedata (Filedata *filedata)
     }
 
   free (filedata->section_headers_groups);
-  filedata->section_headers_groups = NULL;
 
   if (filedata->section_groups)
     {
@@ -21247,8 +21226,9 @@ free_filedata (Filedata *filedata)
 	}
 
       free (filedata->section_groups);
-      filedata->section_groups = NULL;
     }
+  memset (&filedata->section_headers, 0,
+	  sizeof (Filedata) - offsetof (Filedata, section_headers));
 }
 
 static void