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From ad32986fdf9da1c8748e47b8b45100398223dba8 Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Tue, 4 Apr 2017 11:23:36 +0100
Subject: [PATCH] Fix null pointer dereferences when using a link built with
clang.
PR binutils/21342
* elflink.c (_bfd_elf_define_linkage_sym): Prevent null pointer
dereference.
(bfd_elf_final_link): Only initialize the extended symbol index
section if there are extended symbol tables to list.
---
bfd/elflink.c | 35 +++++++++++++++++++++--------------
2 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 776357f..9bf75c8 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -119,15 +119,18 @@ _bfd_elf_define_linkage_sym (bfd *abfd,
defined in shared libraries can't be overridden, because we
lose the link to the bfd which is via the symbol section. */
h->root.type = bfd_link_hash_new;
+ bh = &h->root;
}
+ else
+ bh = NULL;
- bh = &h->root;
bed = get_elf_backend_data (abfd);
if (!_bfd_generic_link_add_one_symbol (info, abfd, name, BSF_GLOBAL,
sec, 0, NULL, FALSE, bed->collect,
&bh))
return NULL;
h = (struct elf_link_hash_entry *) bh;
+ BFD_ASSERT (h != NULL);
h->def_regular = 1;
h->non_elf = 0;
h->root.linker_def = 1;
@@ -12038,24 +12041,28 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
{
/* Finish up and write out the symbol string table (.strtab)
section. */
- Elf_Internal_Shdr *symstrtab_hdr;
+ Elf_Internal_Shdr *symstrtab_hdr = NULL;
file_ptr off = symtab_hdr->sh_offset + symtab_hdr->sh_size;
- symtab_shndx_hdr = & elf_symtab_shndx_list (abfd)->hdr;
- if (symtab_shndx_hdr != NULL && symtab_shndx_hdr->sh_name != 0)
+ if (elf_symtab_shndx_list (abfd))
{
- symtab_shndx_hdr->sh_type = SHT_SYMTAB_SHNDX;
- symtab_shndx_hdr->sh_entsize = sizeof (Elf_External_Sym_Shndx);
- symtab_shndx_hdr->sh_addralign = sizeof (Elf_External_Sym_Shndx);
- amt = bfd_get_symcount (abfd) * sizeof (Elf_External_Sym_Shndx);
- symtab_shndx_hdr->sh_size = amt;
+ symtab_shndx_hdr = & elf_symtab_shndx_list (abfd)->hdr;
- off = _bfd_elf_assign_file_position_for_section (symtab_shndx_hdr,
- off, TRUE);
+ if (symtab_shndx_hdr != NULL && symtab_shndx_hdr->sh_name != 0)
+ {
+ symtab_shndx_hdr->sh_type = SHT_SYMTAB_SHNDX;
+ symtab_shndx_hdr->sh_entsize = sizeof (Elf_External_Sym_Shndx);
+ symtab_shndx_hdr->sh_addralign = sizeof (Elf_External_Sym_Shndx);
+ amt = bfd_get_symcount (abfd) * sizeof (Elf_External_Sym_Shndx);
+ symtab_shndx_hdr->sh_size = amt;
- if (bfd_seek (abfd, symtab_shndx_hdr->sh_offset, SEEK_SET) != 0
- || (bfd_bwrite (flinfo.symshndxbuf, amt, abfd) != amt))
- return FALSE;
+ off = _bfd_elf_assign_file_position_for_section (symtab_shndx_hdr,
+ off, TRUE);
+
+ if (bfd_seek (abfd, symtab_shndx_hdr->sh_offset, SEEK_SET) != 0
+ || (bfd_bwrite (flinfo.symshndxbuf, amt, abfd) != amt))
+ return FALSE;
+ }
}
symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
--
2.9.3
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