Allow readelf to issue warnings if checking is enabled and there are discrepancies...

	PR binutils/25809
	* readelf.c (process_program_headers): Warn if the PT_DYNAMIC
	segment doesn't match the .dynamic section and checks are
	enabled.
	(struct filedata): Add dynamic_symtab_section and
	dynamic_strtab_section fields.
	(process_section_headers): Set dynamic_symtab_section to the
	.dynsym section.  Set dynamic_strtab_section to the .dynstr
	section.
	(process_dynamic_section): Warn if the .dynsym section doesn't
	match DT_SYMTAB and DT_SYMENT or the .dynstr section doesn't
	DT_STRTAB and DT_STRSZ.  But only if checks are enabled.

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index bc0c99907bfa9a4825d562940d9aa674cc906858..76de37e449a6dd27b6cd63cd2a8b2f79482adc78 100644 (file)
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,18 @@
+2020-05-19  H.J. Lu  <hjl.tools@gmail.com>
+
+       PR binutils/25809
+       * readelf.c (process_program_headers): Warn if the PT_DYNAMIC
+       segment doesn't match the .dynamic section and checks are
+       enabled.
+       (struct filedata): Add dynamic_symtab_section and
+       dynamic_strtab_section fields.
+       (process_section_headers): Set dynamic_symtab_section to the
+       .dynsym section.  Set dynamic_strtab_section to the .dynstr
+       section.
+       (process_dynamic_section): Warn if the .dynsym section doesn't
+       match DT_SYMTAB and DT_SYMENT or the .dynstr section doesn't
+       DT_STRTAB and DT_STRSZ.  But only if checks are enabled.
+
 2020-05-19  Alan Modra  <amodra@gmail.com>
 
        * ar.c (map_over_members, get_pos_bfd, delete_members, move_members),

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 6bf6d5294ccfc746c9c0d66bfc058969b7f6571e..87bb574129fb5b67f2ddc1dde9f6fe45ed7da381 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -267,8 +267,10 @@ typedef struct filedata
   bfd_size_type        dynamic_size;
   size_t               dynamic_nent;
   Elf_Internal_Dyn *   dynamic_section;
+  Elf_Internal_Shdr *  dynamic_strtab_section;
   char *               dynamic_strings;
   unsigned long        dynamic_strings_length;
+  Elf_Internal_Shdr *  dynamic_symtab_section;
   unsigned long        num_dynamic_syms;
   Elf_Internal_Sym *   dynamic_symbols;
   bfd_vma              version_info[16];
@@ -5363,13 +5365,13 @@ process_program_headers (Filedata * filedata)
              filedata->dynamic_addr = sec->sh_offset;
              filedata->dynamic_size = sec->sh_size;
 
-             if (filedata->dynamic_addr < segment->p_offset
-                 || filedata->dynamic_addr > segment->p_offset + segment->p_filesz)
-               warn (_("the .dynamic section is not contained"
-                       " within the dynamic segment\n"));
-             else if (filedata->dynamic_addr > segment->p_offset)
-               warn (_("the .dynamic section is not the first section"
-                       " in the dynamic segment.\n"));
+             /* The PT_DYNAMIC segment, which is used by the run-time
+                loader,  should exactly match the .dynamic section.  */
+             if (do_checks
+                 && (filedata->dynamic_addr != segment->p_offset
+                     || filedata->dynamic_size != segment->p_filesz))
+               warn (_("\
+the .dynamic section is not the same as the dynamic segment\n"));
            }
 
          /* PR binutils/17512: Avoid corrupt dynamic section info in the
@@ -6319,6 +6321,7 @@ process_section_headers (Filedata * filedata)
          CHECK_ENTSIZE (section, i, Sym);
          filedata->dynamic_symbols
            = GET_ELF_SYMBOLS (filedata, section, &filedata->num_dynamic_syms);
+         filedata->dynamic_symtab_section = section;
          break;
 
        case SHT_STRTAB:
@@ -6335,6 +6338,7 @@ process_section_headers (Filedata * filedata)
                                     1, section->sh_size, _("dynamic strings"));
              filedata->dynamic_strings_length
                = filedata->dynamic_strings == NULL ? 0 : section->sh_size;
+             filedata->dynamic_strtab_section = section;
            }
          break;
 
@@ -10341,6 +10345,18 @@ process_dynamic_section (Filedata * filedata)
                  section.sh_size = (num_of_syms
                                     * filedata->dynamic_info[DT_SYMENT]);
                  section.sh_entsize = filedata->dynamic_info[DT_SYMENT];
+
+                 if (do_checks
+                     && filedata->dynamic_symtab_section != NULL
+                     && ((filedata->dynamic_symtab_section->sh_offset
+                          != section.sh_offset)
+                         || (filedata->dynamic_symtab_section->sh_size
+                             != section.sh_size)
+                         || (filedata->dynamic_symtab_section->sh_entsize
+                             != section.sh_entsize)))
+                   warn (_("\
+the .dynsym section doesn't match the DT_SYMTAB and DT_SYMENT tags\n"));
+
                  section.sh_name = filedata->string_table_length;
                  filedata->dynamic_symbols
                    = GET_ELF_SYMBOLS (filedata, &section,
@@ -10378,6 +10394,15 @@ process_dynamic_section (Filedata * filedata)
            offset = offset_from_vma (filedata,
                                      filedata->dynamic_info[DT_STRTAB],
                                      str_tab_len);
+           if (do_checks
+               && filedata->dynamic_strtab_section
+               && ((filedata->dynamic_strtab_section->sh_offset
+                    != (file_ptr) offset)
+                   || (filedata->dynamic_strtab_section->sh_size
+                       != str_tab_len)))
+             warn (_("\
+the .dynstr section doesn't match the DT_STRTAB and DT_STRSZ tags\n"));
+
            filedata->dynamic_strings
              = (char *) get_data (NULL, filedata, offset, 1, str_tab_len,
                                   _("dynamic string table"));