Commit d1fc98ba authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fixes from Peter Anvin:
 "A pile of fixes related to the VDSO, EFI and 32-bit badsys handling.

  It turns out that removing the section headers from the VDSO breaks
  gdb, so this puts back most of them.  A very simple typo broke
  rt_sigreturn on some versions of glibc, with obviously disastrous
  results.  The rest is pretty much fixes for the corresponding fallout.

  The EFI fixes fixes an arithmetic overflow on 32-bit systems and
  quiets some build warnings.

  Finally, when invoking an invalid system call number on x86-32, we
  bypass a bunch of handling, which can make the audit code oops"

* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi-pstore: Fix an overflow on 32-bit builds
  x86/vdso: Error out in vdso2c if DT_RELA is present
  x86/vdso: Move DISABLE_BRANCH_PROFILING into the vdso makefile
  x86_32, signal: Fix vdso rt_sigreturn
  x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)
  x86/vdso: Create .build-id links for unstripped vdso files
  x86/vdso: Remove some redundant in-memory section headers
  x86/vdso: Improve the fake section headers
  x86/vdso2c: Use better macros for ELF bitness
  x86/vdso: Discard the __bug_table section
  efi: Fix compiler warnings (unused, const, type)
parents c9a60666 ba3f35c7

arch/x86/kernel/entry_32.S

+8 −2
Original line number Diff line number Diff line
@@ -423,9 +423,10 @@ sysenter_past_esp: 
	jnz sysenter_audit

sysenter_do_call:

	cmpl $(NR_syscalls), %eax

	jae syscall_badsys

	jae sysenter_badsys

	call *sys_call_table(,%eax,4)

	movl %eax,PT_EAX(%esp)

sysenter_after_call:

	LOCKDEP_SYS_EXIT

	DISABLE_INTERRUPTS(CLBR_ANY)

	TRACE_IRQS_OFF
@@ -675,7 +676,12 @@ END(syscall_fault) 


syscall_badsys:

	movl $-ENOSYS,PT_EAX(%esp)

	jmp resume_userspace

	jmp syscall_exit

END(syscall_badsys)



sysenter_badsys:

	movl $-ENOSYS,PT_EAX(%esp)

	jmp sysenter_after_call

END(syscall_badsys)

	CFI_ENDPROC

arch/x86/kernel/signal.c

+1 −1
Original line number Diff line number Diff line
@@ -363,7 +363,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, 


		/* Set up to return from userspace.  */

		restorer = current->mm->context.vdso +

			selected_vdso32->sym___kernel_sigreturn;

			selected_vdso32->sym___kernel_rt_sigreturn;

		if (ksig->ka.sa.sa_flags & SA_RESTORER)

			restorer = ksig->ka.sa.sa_restorer;

		put_user_ex(restorer, &frame->pretcode);

arch/x86/vdso/Makefile

+18 −6
Original line number Diff line number Diff line
@@ -11,7 +11,6 @@ VDSO32-$(CONFIG_COMPAT) := y 


# files to link into the vdso

vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vdso-fakesections.o

vobjs-nox32 := vdso-fakesections.o



# files to link into kernel

obj-y				+= vma.o
@@ -67,7 +66,8 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso2c FORCE 
#

CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \

       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \

       -fno-omit-frame-pointer -foptimize-sibling-calls

       -fno-omit-frame-pointer -foptimize-sibling-calls \

       -DDISABLE_BRANCH_PROFILING



$(vobjs): KBUILD_CFLAGS += $(CFL)
@@ -134,7 +134,7 @@ override obj-dirs = $(dir $(obj)) $(obj)/vdso32/ 


targets += vdso32/vdso32.lds

targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)

targets += vdso32/vclock_gettime.o

targets += vdso32/vclock_gettime.o vdso32/vdso-fakesections.o



$(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
@@ -150,11 +150,13 @@ KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic 
KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)

KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)

KBUILD_CFLAGS_32 += -fno-omit-frame-pointer

KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING

$(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)



$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \

				 $(obj)/vdso32/vdso32.lds \

				 $(obj)/vdso32/vclock_gettime.o \

				 $(obj)/vdso32/vdso-fakesections.o \

				 $(obj)/vdso32/note.o \

				 $(obj)/vdso32/%.o

	$(call if_changed,vdso)
@@ -169,14 +171,24 @@ quiet_cmd_vdso = VDSO $@ 
		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'



VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \

	-Wl,-Bsymbolic $(LTO_CFLAGS)

	$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)

GCOV_PROFILE := n



#

# Install the unstripped copies of vdso*.so.

# Install the unstripped copies of vdso*.so.  If our toolchain supports

# build-id, install .build-id links as well.

#

quiet_cmd_vdso_install = INSTALL $(@:install_%=%)

      cmd_vdso_install = cp $< $(MODLIB)/vdso/$(@:install_%=%)

define cmd_vdso_install

	cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \

	if readelf -n $< |grep -q 'Build ID'; then \

	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \

	  first=`echo $$buildid | cut -b-2`; \

	  last=`echo $$buildid | cut -b3-`; \

	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \

	  ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \

	fi

endef



vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)

arch/x86/vdso/vclock_gettime.c

+0 −3
Original line number Diff line number Diff line
@@ -11,9 +11,6 @@ 
 * Check with readelf after changing.

 */



/* Disable profiling for userspace code: */

#define DISABLE_BRANCH_PROFILING



#include <uapi/linux/time.h>

#include <asm/vgtod.h>

#include <asm/hpet.h>

arch/x86/vdso/vdso-fakesections.c

+15 −26
Original line number Diff line number Diff line
@@ -2,31 +2,20 @@ 
 * Copyright 2014 Andy Lutomirski

 * Subject to the GNU Public License, v.2

 *

 * Hack to keep broken Go programs working.

 *

 * The Go runtime had a couple of bugs: it would read the section table to try

 * to figure out how many dynamic symbols there were (it shouldn't have looked

 * at the section table at all) and, if there were no SHT_SYNDYM section table

 * entry, it would use an uninitialized value for the number of symbols.  As a

 * workaround, we supply a minimal section table.  vdso2c will adjust the

 * in-memory image so that "vdso_fake_sections" becomes the section table.

 *

 * The bug was introduced by:

 * https://code.google.com/p/go/source/detail?r=56ea40aac72b (2012-08-31)

 * and is being addressed in the Go runtime in this issue:

 * https://code.google.com/p/go/issues/detail?id=8197

 * String table for loadable section headers.  See vdso2c.h for why

 * this exists.

 */



#ifndef __x86_64__

#error This hack is specific to the 64-bit vDSO

#endif



#include <linux/elf.h>



extern const __visible struct elf64_shdr vdso_fake_sections[];

const __visible struct elf64_shdr vdso_fake_sections[] = {

	{

		.sh_type = SHT_DYNSYM,

		.sh_entsize = sizeof(Elf64_Sym),

	}

};
 
const char fake_shstrtab[] __attribute__((section(".fake_shstrtab"))) =

	".hash\0"

	".dynsym\0"

	".dynstr\0"

	".gnu.version\0"

	".gnu.version_d\0"

	".dynamic\0"

	".rodata\0"

	".fake_shstrtab\0"  /* Yay, self-referential code. */

	".note\0"

	".eh_frame_hdr\0"

	".eh_frame\0"

	".text";

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