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78 lines
2.5 KiB
Diff
78 lines
2.5 KiB
Diff
From 8642dafaef21aa6747cec01df1977e9c52eb4679 Mon Sep 17 00:00:00 2001
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From: Alan Modra <amodra@gmail.com>
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Date: Fri, 4 Sep 2020 19:19:18 +0930
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Subject: [PATCH] PR26574, heap buffer overflow in
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_bfd_elf_slurp_secondary_reloc_section
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A horribly fuzzed object with section headers inside the ELF header.
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Disallow that, and crazy reloc sizes.
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PR 26574
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* elfcode.h (elf_object_p): Sanity check section header offset.
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* elf.c (_bfd_elf_slurp_secondary_reloc_section): Sanity check
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sh_entsize.
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---
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bfd/elf.c | 4 +++-
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bfd/elfcode.h | 8 ++++----
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3 files changed, 14 insertions(+), 5 deletions(-)
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diff --git a/bfd/elf.c b/bfd/elf.c
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index ac2095f787d..5a02f8dc309 100644
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--- a/bfd/elf.c
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+++ b/bfd/elf.c
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@@ -12576,7 +12576,9 @@ _bfd_elf_slurp_secondary_reloc_section (bfd * abfd,
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Elf_Internal_Shdr * hdr = & elf_section_data (relsec)->this_hdr;
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if (hdr->sh_type == SHT_SECONDARY_RELOC
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- && hdr->sh_info == (unsigned) elf_section_data (sec)->this_idx)
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+ && hdr->sh_info == (unsigned) elf_section_data (sec)->this_idx
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+ && (hdr->sh_entsize == ebd->s->sizeof_rel
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+ || hdr->sh_entsize == ebd->s->sizeof_rela))
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{
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bfd_byte * native_relocs;
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bfd_byte * native_reloc;
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diff --git a/bfd/elfcode.h b/bfd/elfcode.h
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index 2ed2f135c34..606ff64fd4d 100644
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--- a/bfd/elfcode.h
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+++ b/bfd/elfcode.h
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@@ -571,7 +571,7 @@ elf_object_p (bfd *abfd)
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/* If this is a relocatable file and there is no section header
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table, then we're hosed. */
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- if (i_ehdrp->e_shoff == 0 && i_ehdrp->e_type == ET_REL)
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+ if (i_ehdrp->e_shoff < sizeof (x_ehdr) && i_ehdrp->e_type == ET_REL)
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goto got_wrong_format_error;
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/* As a simple sanity check, verify that what BFD thinks is the
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@@ -581,7 +581,7 @@ elf_object_p (bfd *abfd)
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goto got_wrong_format_error;
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/* Further sanity check. */
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- if (i_ehdrp->e_shoff == 0 && i_ehdrp->e_shnum != 0)
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+ if (i_ehdrp->e_shoff < sizeof (x_ehdr) && i_ehdrp->e_shnum != 0)
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goto got_wrong_format_error;
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ebd = get_elf_backend_data (abfd);
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@@ -618,7 +618,7 @@ elf_object_p (bfd *abfd)
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&& ebd->elf_osabi != ELFOSABI_NONE)
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goto got_wrong_format_error;
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- if (i_ehdrp->e_shoff != 0)
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+ if (i_ehdrp->e_shoff >= sizeof (x_ehdr))
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{
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file_ptr where = (file_ptr) i_ehdrp->e_shoff;
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@@ -819,7 +819,7 @@ elf_object_p (bfd *abfd)
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}
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}
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- if (i_ehdrp->e_shstrndx != 0 && i_ehdrp->e_shoff != 0)
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+ if (i_ehdrp->e_shstrndx != 0 && i_ehdrp->e_shoff >= sizeof (x_ehdr))
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{
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unsigned int num_sec;
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--
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2.27.0
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