Unaligned memory access issues (#891553)

This commit is contained in:
Mark Wielaard 2013-01-10 11:06:19 +01:00
parent 2a5e99f3ec
commit 091b5a9425
3 changed files with 200 additions and 11 deletions

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@ -1,10 +0,0 @@
diff --git a/tests/run-elflint-self.sh b/tests/run-elflint-self.sh
index 8aca9e1..d449416 100755
--- a/tests/run-elflint-self.sh
+++ b/tests/run-elflint-self.sh
@@ -51,4 +51,4 @@ runtest ../libebl/libebl_sh.so
runtest ../libebl/libebl_sparc.so
runtest ../libebl/libebl_x86_64.so
-exit $status
+test $status == 0 || echo "binutils PR ld/13621 workaround"

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@ -0,0 +1,194 @@
--- a/libdw/ChangeLog 2012-08-27 20:29:31.000000000 +0200
+++ b/libdw/ChangeLog 2013-01-10 10:59:28.039026230 +0100
@@ -1,3 +1,9 @@
+2013-01-07 Roland McGrath <roland@hack.frob.com>
+
+ * memory-access.h
+ [ALLOW_UNALIGNED] (read_8ubyte_unaligned_noncvt): New macro.
+ [!ALLOW_UNALIGNED] (read_8ubyte_unaligned_noncvt): New inline function.
+
2012-08-24 Mark Wielaard <mjw@redhat.com>
* dwarf_begin_elf.c (check_section): Only probe for dwz multi files
--- a/libdw/memory-access.h 2012-08-27 20:27:31.000000000 +0200
+++ b/libdw/memory-access.h 2013-01-10 10:56:07.171152555 +0100
@@ -1,5 +1,5 @@
/* Unaligned memory access functionality.
- Copyright (C) 2000-2010 Red Hat, Inc.
+ Copyright (C) 2000-2013 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 2001.
@@ -147,6 +147,8 @@
? (int32_t) bswap_32 (*((const int32_t *) (Addr))) \
: *((const int32_t *) (Addr)))
+# define read_8ubyte_unaligned_noncvt(Addr) \
+ *((const uint64_t *) (Addr))
# define read_8ubyte_unaligned(Dbg, Addr) \
(unlikely ((Dbg)->other_byte_order) \
? bswap_64 (*((const uint64_t *) (Addr))) \
@@ -223,6 +225,12 @@
}
static inline uint64_t
+read_8ubyte_unaligned_noncvt (const void *p)
+{
+ const union unaligned *up = p;
+ return up->u8;
+}
+static inline uint64_t
read_8ubyte_unaligned_1 (bool other_byte_order, const void *p)
{
const union unaligned *up = p;
--- a/libdwfl/ChangeLog 2013-01-10 10:59:53.882008409 +0100
+++ b/libdwfl/ChangeLog 2013-01-10 10:57:48.451130775 +0100
@@ -1,3 +1,9 @@
+2013-01-07 Roland McGrath <roland@hack.frob.com>
+
+ * link_map.c (auxv_format_probe): Handle unaligned 64-bit data, but
+ still assume the data is at least 32-bit aligned anyway.
+ (dwfl_link_map_report): Handle unaligned auxv data.
+
2012-08-01 Petr Machata <pmachata@redhat.com>
* offline.c (process_archive_member): Ignore entry "/SYM64/".
--- a/libdwfl/link_map.c 2012-08-27 20:27:31.000000000 +0200
+++ b/libdwfl/link_map.c 2013-01-10 10:56:07.207002831 +0100
@@ -1,5 +1,5 @@
/* Report modules by examining dynamic linker data structures.
- Copyright (C) 2008-2010 Red Hat, Inc.
+ Copyright (C) 2008-2013 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -28,6 +28,7 @@
#include <config.h>
#include "libdwflP.h"
+#include "../libdw/memory-access.h"
#include <byteswap.h>
#include <endian.h>
@@ -66,15 +67,22 @@
inline bool check64 (size_t i)
{
- if (u->a64[i].a_type == BE64 (PROBE_TYPE)
- && u->a64[i].a_un.a_val == BE64 (PROBE_VAL64))
+ /* The AUXV pointer might not even be naturally aligned for 64-bit
+ data, because note payloads in a core file are not aligned.
+ But we assume the data is 32-bit aligned. */
+
+ uint64_t type = read_8ubyte_unaligned_noncvt (&u->a64[i].a_type);
+ uint64_t val = read_8ubyte_unaligned_noncvt (&u->a64[i].a_un.a_val);
+
+ if (type == BE64 (PROBE_TYPE)
+ && val == BE64 (PROBE_VAL64))
{
*elfdata = ELFDATA2MSB;
return true;
}
- if (u->a64[i].a_type == LE64 (PROBE_TYPE)
- && u->a64[i].a_un.a_val == LE64 (PROBE_VAL64))
+ if (type == LE64 (PROBE_TYPE)
+ && val == LE64 (PROBE_VAL64))
{
*elfdata = ELFDATA2LSB;
return true;
@@ -618,29 +626,32 @@
GElf_Xword phent = 0;
GElf_Xword phnum = 0;
-#define AUXV_SCAN(NN, BL) do \
- { \
- const Elf##NN##_auxv_t *av = auxv; \
- for (size_t i = 0; i < auxv_size / sizeof av[0]; ++i) \
- { \
- Elf##NN##_Addr val = BL##NN (av[i].a_un.a_val); \
- if (av[i].a_type == BL##NN (AT_ENTRY)) \
- entry = val; \
- else if (av[i].a_type == BL##NN (AT_PHDR)) \
- phdr = val; \
- else if (av[i].a_type == BL##NN (AT_PHNUM)) \
- phnum = val; \
- else if (av[i].a_type == BL##NN (AT_PHENT)) \
- phent = val; \
- else if (av[i].a_type == BL##NN (AT_PAGESZ)) \
- { \
- if (val > 1 \
- && (dwfl->segment_align == 0 \
- || val < dwfl->segment_align)) \
- dwfl->segment_align = val; \
- } \
- } \
- } \
+#define READ_AUXV32(ptr) read_4ubyte_unaligned_noncvt (ptr)
+#define READ_AUXV64(ptr) read_8ubyte_unaligned_noncvt (ptr)
+#define AUXV_SCAN(NN, BL) do \
+ { \
+ const Elf##NN##_auxv_t *av = auxv; \
+ for (size_t i = 0; i < auxv_size / sizeof av[0]; ++i) \
+ { \
+ uint##NN##_t type = READ_AUXV##NN (&av[i].a_type); \
+ uint##NN##_t val = BL##NN (READ_AUXV##NN (&av[i].a_un.a_val)); \
+ if (type == BL##NN (AT_ENTRY)) \
+ entry = val; \
+ else if (type == BL##NN (AT_PHDR)) \
+ phdr = val; \
+ else if (type == BL##NN (AT_PHNUM)) \
+ phnum = val; \
+ else if (type == BL##NN (AT_PHENT)) \
+ phent = val; \
+ else if (type == BL##NN (AT_PAGESZ)) \
+ { \
+ if (val > 1 \
+ && (dwfl->segment_align == 0 \
+ || val < dwfl->segment_align)) \
+ dwfl->segment_align = val; \
+ } \
+ } \
+ } \
while (0)
if (elfclass == ELFCLASS32)
--- a/libelf/ChangeLog 2013-01-10 10:59:53.884010033 +0100
+++ b/libelf/ChangeLog 2013-01-10 10:58:57.505003982 +0100
@@ -1,3 +1,13 @@
+2013-01-07 Roland McGrath <roland@hack.frob.com>
+
+ * elf_getarsym.c (elf_getarsym): Copy FILE_DATA into stack space if it
+ would be unaligned and !ALLOW_UNALIGNED.
+
+2013-01-07 Roland McGrath <roland@hack.frob.com>
+
+ * elf_getarsym.c (read_number_entries): Use memcpy instead of pointer
+ dereference so as not to assume the field is naturally aligned.
+
2012-08-16 Roland McGrath <roland@hack.frob.com>
* elf.h: Update from glibc.
--- a/libelf/elf_getarsym.c 2013-01-10 10:59:53.888006636 +0100
+++ b/libelf/elf_getarsym.c 2013-01-10 10:56:07.210254028 +0100
@@ -57,7 +57,9 @@
size_t w = index64_p ? 8 : 4;
if (elf->map_address != NULL)
- u = *(union u *) (elf->map_address + *offp);
+ /* Use memcpy instead of pointer dereference so as not to assume the
+ field is naturally aligned within the file. */
+ memcpy (&u, elf->map_address + *offp, sizeof u);
else if ((size_t) pread_retry (elf->fildes, &u, w, *offp) != w)
return -1;
@@ -241,6 +243,9 @@
else
{
file_data = (void *) (elf->map_address + off);
+ if (!ALLOW_UNALIGNED
+ && ((uintptr_t) file_data & -(uintptr_t) n) != 0)
+ file_data = memcpy (alloca (sz), elf->map_address + off, sz);
str_data = (char *) (elf->map_address + off + sz);
}

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@ -1,7 +1,7 @@
Name: elfutils
Summary: A collection of utilities and DSOs to handle compiled objects
Version: 0.155
%global baserelease 1
%global baserelease 2
URL: https://fedorahosted.org/elfutils/
%global source_url http://fedorahosted.org/releases/e/l/elfutils/%{version}/
License: GPLv3+ and (GPLv2+ or LGPLv3+)
@ -46,6 +46,7 @@ Source: %{?source_url}%{name}-%{version}.tar.bz2
Patch1: %{?source_url}elfutils-robustify.patch
Patch2: %{?source_url}elfutils-portability.patch
Patch3: elfutils-0.155-binutils-pr-ld-13621.patch
Patch4: elfutils-0.155-mem-align.patch
%if !%{compat}
Release: %{baserelease}%{?dist}
@ -211,6 +212,7 @@ sed -i.scanf-m -e 's/%m/%a/g' src/addr2line.c tests/line2addr.c
%endif
%patch3 -p1 -b .binutils-pr-ld-13621
%patch4 -p1 -b .mem-align
find . -name \*.sh ! -perm -0100 -print | xargs chmod +x
@ -327,6 +329,9 @@ rm -rf ${RPM_BUILD_ROOT}
%{_libdir}/libelf.a
%changelog
* Thu Jan 10 2013 Mark Wielaard <mjw@redhat.com> - 0.155-2
- #891553 - unaligned memory access issues.
* Mon Aug 27 2012 Mark Wielaard <mjw@redhat.com> - 0.155-1
- Update to 0.155.
- #844270 - eu-nm invalid %N$ use detected.