Fix: A potential bug of null pointer dereference

[thirdparty/binutils-gdb.git] / bfd / elflink.c

diff --git a/bfd/elflink.c b/bfd/elflink.c
index f10faa5f8bde8028248b6c07fb2327d1276df15f..99f4cdd5527139f3af9f75e5e932b05fd0986046 100644 (file)
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -2651,7 +2651,7 @@ elf_link_read_relocs_from_section (bfd *abfd,
     return false;
 
   /* Read the relocations.  */
-  if (bfd_bread (external_relocs, shdr->sh_size, abfd) != shdr->sh_size)
+  if (bfd_read (external_relocs, shdr->sh_size, abfd) != shdr->sh_size)
     return false;
 
   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
@@ -3586,10 +3586,19 @@ elf_link_is_defined_archive_symbol (bfd * abfd, carsym * symdef)
       abfd = abfd->plugin_dummy_bfd;
       hdr = &elf_tdata (abfd)->symtab_hdr;
     }
-  else if ((abfd->flags & DYNAMIC) == 0 || elf_dynsymtab (abfd) == 0)
-    hdr = &elf_tdata (abfd)->symtab_hdr;
   else
-    hdr = &elf_tdata (abfd)->dynsymtab_hdr;
+    {
+      if (elf_use_dt_symtab_p (abfd))
+       {
+         bfd_set_error (bfd_error_wrong_format);
+         return false;
+       }
+
+      if ((abfd->flags & DYNAMIC) == 0 || elf_dynsymtab (abfd) == 0)
+       hdr = &elf_tdata (abfd)->symtab_hdr;
+      else
+       hdr = &elf_tdata (abfd)->dynsymtab_hdr;
+    }
 
   symcount = hdr->sh_size / get_elf_backend_data (abfd)->s->sizeof_sym;
 
@@ -4233,6 +4242,12 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
   htab = elf_hash_table (info);
   bed = get_elf_backend_data (abfd);
 
+  if (elf_use_dt_symtab_p (abfd))
+    {
+      bfd_set_error (bfd_error_wrong_format);
+      return false;
+    }
+
   if ((abfd->flags & DYNAMIC) == 0)
     dynamic = false;
   else
@@ -5302,10 +5317,14 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
                  else
                    _bfd_error_handler
                      /* xgettext:c-format */
-                     (_("warning: alignment %u of symbol `%s' in %pB"
-                        " is smaller than %u in %pB"),
+                     (_("warning: alignment %u of normal symbol `%s' in %pB"
+                        " is smaller than %u used by the common definition in %pB"),
                       1 << normal_align, name, normal_bfd,
                       1 << common_align, common_bfd);
+
+                 /* PR 30499: make sure that users understand that this warning is serious.  */
+                 _bfd_error_handler
+                   (_("warning: NOTE: alignment discrepancies can cause real problems.  Investigation is advised."));
                }
            }
 
@@ -5317,12 +5336,18 @@ elf_link_add_object_symbols (bfd *abfd, struct bfd_link_info *info)
              if (h->size != 0
                  && h->size != isym->st_size
                  && ! size_change_ok)
-               _bfd_error_handler
-                 /* xgettext:c-format */
-                 (_("warning: size of symbol `%s' changed"
-                    " from %" PRIu64 " in %pB to %" PRIu64 " in %pB"),
-                  name, (uint64_t) h->size, old_bfd,
-                  (uint64_t) isym->st_size, abfd);
+               {
+                 _bfd_error_handler
+                   /* xgettext:c-format */
+                   (_("warning: size of symbol `%s' changed"
+                      " from %" PRIu64 " in %pB to %" PRIu64 " in %pB"),
+                    name, (uint64_t) h->size, old_bfd,
+                    (uint64_t) isym->st_size, abfd);
+
+                 /* PR 30499: make sure that users understand that this warning is serious.  */
+                 _bfd_error_handler
+                   (_("warning: NOTE: size discrepancies can cause real problems.  Investigation is advised."));
+               }
 
              h->size = isym->st_size;
            }
@@ -10166,7 +10191,7 @@ elf_link_swap_symbols_out (struct elf_final_link_info *flinfo)
   pos = hdr->sh_offset + hdr->sh_size;
   amt = bed->s->sizeof_sym * flinfo->output_bfd->symcount;
   if (bfd_seek (flinfo->output_bfd, pos, SEEK_SET) == 0
-      && bfd_bwrite (symbuf, amt, flinfo->output_bfd) == amt)
+      && bfd_write (symbuf, amt, flinfo->output_bfd) == amt)
     {
       hdr->sh_size += amt;
       ret = true;
@@ -13049,7 +13074,7 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
                                                               off, true);
 
              if (bfd_seek (abfd, symtab_shndx_hdr->sh_offset, SEEK_SET) != 0
-                 || (bfd_bwrite (flinfo.symshndxbuf, amt, abfd) != amt))
+                 || (bfd_write (flinfo.symshndxbuf, amt, abfd) != amt))
                {
                  ret = false;
                  goto return_local_hash_table;
@@ -13685,7 +13710,7 @@ elf_gc_mark_debug_section (asection *sec ATTRIBUTE_UNUSED,
       /* Return the local debug definition section.  */
       asection *isec = bfd_section_from_elf_index (sec->owner,
                                                   sym->st_shndx);
-      if ((isec->flags & SEC_DEBUGGING) != 0)
+      if (isec != NULL && (isec->flags & SEC_DEBUGGING) != 0)
        return isec;
     }