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authorAlan Modra <amodra@gmail.com>2023-04-12 11:00:42 +0930
committerAlan Modra <amodra@gmail.com>2023-04-12 14:13:46 +0930
commit93c6e8c3c14bf81020ca7571fe752250a34f5bc9 (patch)
tree4e5b252048ff1dc9da4da78862aef9e16bf8e765 /bfd
parent32011d23a879283d845993e9358f64a6e8aefa98 (diff)
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PR30326, uninitialised value in objdump compare_relocs
This is a fuzzing PR, with a testcase involving a SHF_ALLOC and SHF_COMPRESSED SHT_RELA section, ie. a compressed dynamic reloc section. BFD doesn't handle compressed relocation sections, with most of the code reading relocs using sh_size (often no bfd section is created) but in the case of SHF_ALLOC dynamic relocs we had some code using the bfd section size. This led to a mismatch, sh_size is compressed, size is uncompressed, and from that some uninitialised memory. Consistently using sh_size is enough to fix this PR, but I've also added tests to exclude SHF_COMPRESSED reloc sections from consideration. PR 30362 * elf.c (bfd_section_from_shdr): Exclude reloc sections with SHF_COMPRESSED flag from normal reloc processing. (_bfd_elf_get_dynamic_reloc_upper_bound): Similarly exclude SHF_COMPRESSED sections from consideration. Use sh_size when sizing to match slurp_relocs. (_bfd_elf_canonicalize_dynamic_reloc): Likewise. (_bfd_elf_get_synthetic_symtab): Use NUM_SHDR_ENTRIES to size plt relocs. * elf32-arm.c (elf32_arm_get_synthetic_symtab): Likewise. * elf32-ppc.c (ppc_elf_get_synthetic_symtab): Likewise. * elf64-ppc.c (ppc64_elf_get_synthetic_symtab): Likewise. * elfxx-mips.c (_bfd_mips_elf_get_synthetic_symtab): Likewise.
Diffstat (limited to 'bfd')
-rw-r--r--bfd/elf.c17
-rw-r--r--bfd/elf32-arm.c2
-rw-r--r--bfd/elf32-ppc.c2
-rw-r--r--bfd/elf64-ppc.c2
-rw-r--r--bfd/elfxx-mips.c2
5 files changed, 14 insertions, 11 deletions
diff --git a/bfd/elf.c b/bfd/elf.c
index 0e2ae6d..fa7c25a 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -2381,6 +2381,7 @@ bfd_section_from_shdr (bfd *abfd, unsigned int shindex)
its sh_link points to the null section. */
if (((abfd->flags & (DYNAMIC | EXEC_P)) != 0
&& (hdr->sh_flags & SHF_ALLOC) != 0)
+ || (hdr->sh_flags & SHF_COMPRESSED) != 0
|| hdr->sh_type == SHT_RELR
|| hdr->sh_link == SHN_UNDEF
|| hdr->sh_link != elf_onesymtab (abfd)
@@ -8728,15 +8729,16 @@ _bfd_elf_get_dynamic_reloc_upper_bound (bfd *abfd)
for (s = abfd->sections; s != NULL; s = s->next)
if (elf_section_data (s)->this_hdr.sh_link == elf_dynsymtab (abfd)
&& (elf_section_data (s)->this_hdr.sh_type == SHT_REL
- || elf_section_data (s)->this_hdr.sh_type == SHT_RELA))
+ || elf_section_data (s)->this_hdr.sh_type == SHT_RELA)
+ && (elf_section_data (s)->this_hdr.sh_flags & SHF_COMPRESSED) == 0)
{
- ext_rel_size += s->size;
- if (ext_rel_size < s->size)
+ ext_rel_size += elf_section_data (s)->this_hdr.sh_size;
+ if (ext_rel_size < elf_section_data (s)->this_hdr.sh_size)
{
bfd_set_error (bfd_error_file_truncated);
return -1;
}
- count += s->size / elf_section_data (s)->this_hdr.sh_entsize;
+ count += NUM_SHDR_ENTRIES (&elf_section_data (s)->this_hdr);
if (count > LONG_MAX / sizeof (arelent *))
{
bfd_set_error (bfd_error_file_too_big);
@@ -8785,14 +8787,15 @@ _bfd_elf_canonicalize_dynamic_reloc (bfd *abfd,
{
if (elf_section_data (s)->this_hdr.sh_link == elf_dynsymtab (abfd)
&& (elf_section_data (s)->this_hdr.sh_type == SHT_REL
- || elf_section_data (s)->this_hdr.sh_type == SHT_RELA))
+ || elf_section_data (s)->this_hdr.sh_type == SHT_RELA)
+ && (elf_section_data (s)->this_hdr.sh_flags & SHF_COMPRESSED) == 0)
{
arelent *p;
long count, i;
if (! (*slurp_relocs) (abfd, s, syms, true))
return -1;
- count = s->size / elf_section_data (s)->this_hdr.sh_entsize;
+ count = NUM_SHDR_ENTRIES (&elf_section_data (s)->this_hdr);
p = s->relocation;
for (i = 0; i < count; i++)
*storage++ = p++;
@@ -12936,7 +12939,7 @@ _bfd_elf_get_synthetic_symtab (bfd *abfd,
if (! (*slurp_relocs) (abfd, relplt, dynsyms, true))
return -1;
- count = relplt->size / hdr->sh_entsize;
+ count = NUM_SHDR_ENTRIES (hdr);
size = count * sizeof (asymbol);
p = relplt->relocation;
for (i = 0; i < count; i++, p += bed->s->int_rels_per_ext_rel)
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index e07e122..7041366 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -20067,7 +20067,7 @@ elf32_arm_get_synthetic_symtab (bfd *abfd,
plt->flags |= SEC_IN_MEMORY;
}
- count = relplt->size / hdr->sh_entsize;
+ count = NUM_SHDR_ENTRIES (hdr);
size = count * sizeof (asymbol);
p = relplt->relocation;
for (i = 0; i < count; i++, p += elf32_arm_size_info.int_rels_per_ext_rel)
diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c
index bb77ba2..2cff158 100644
--- a/bfd/elf32-ppc.c
+++ b/bfd/elf32-ppc.c
@@ -1920,7 +1920,7 @@ ppc_elf_get_synthetic_symtab (bfd *abfd, long symcount, asymbol **syms,
}
}
- count = relplt->size / sizeof (Elf32_External_Rela);
+ count = NUM_SHDR_ENTRIES (&elf_section_data (relplt)->this_hdr);
/* If the stubs are those for -shared/-pie then we might have
multiple stubs for each plt entry. If that is the case then
there is no way to associate stubs with their plt entries short
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 069bd75..daa6dee 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -2576,7 +2576,7 @@ ppc64_elf_get_synthetic_symtab (bfd *abfd,
if (!(*slurp_relocs) (abfd, relplt, dyn_syms, true))
goto free_contents_and_exit_err;
- plt_count = relplt->size / sizeof (Elf64_External_Rela);
+ plt_count = NUM_SHDR_ENTRIES (&elf_section_data (relplt)->this_hdr);
size += plt_count * sizeof (asymbol);
p = relplt->relocation;
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index d34a755..751deed 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -16595,7 +16595,7 @@ _bfd_mips_elf_get_synthetic_symtab (bfd *abfd,
/* Calculating the exact amount of space required for symbols would
require two passes over the PLT, so just pessimise assuming two
PLT slots per relocation. */
- count = relplt->size / hdr->sh_entsize;
+ count = NUM_SHDR_ENTRIES (hdr);
counti = count * bed->s->int_rels_per_ext_rel;
size = 2 * count * sizeof (asymbol);
size += count * (sizeof (mipssuffix) +