Revision c715b72c1ba406f133217b509044c38d8e714a37 authored by Kees Cook on 18 August 2017, 22:16:31 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC
Moving the x86_64 and arm64 PIE base from 0x555555554000 to 0x000100000000
broke AddressSanitizer.  This is a partial revert of:

  eab09532d400 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE")
  02445990a96e ("arm64: move ELF_ET_DYN_BASE to 4GB / 4MB")

The AddressSanitizer tool has hard-coded expectations about where
executable mappings are loaded.

The motivation for changing the PIE base in the above commits was to
avoid the Stack-Clash CVEs that allowed executable mappings to get too
close to heap and stack.  This was mainly a problem on 32-bit, but the
64-bit bases were moved too, in an effort to proactively protect those
systems (proofs of concept do exist that show 64-bit collisions, but
other recent changes to fix stack accounting and setuid behaviors will
minimize the impact).

The new 32-bit PIE base is fine for ASan (since it matches the ET_EXEC
base), so only the 64-bit PIE base needs to be reverted to let x86 and
arm64 ASan binaries run again.  Future changes to the 64-bit PIE base on
these architectures can be made optional once a more dynamic method for
dealing with AddressSanitizer is found.  (e.g.  always loading PIE into
the mmap region for marked binaries.)

Link: http://lkml.kernel.org/r/20170807201542.GA21271@beast
Fixes: eab09532d400 ("binfmt_elf: use ELF_ET_DYN_BASE only for PIE")
Fixes: 02445990a96e ("arm64: move ELF_ET_DYN_BASE to 4GB / 4MB")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Kostya Serebryany <kcc@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 704b862
Raw File
Makefile.headersinst
# ==========================================================================
# Installing headers
#
# All headers under include/uapi, include/generated/uapi,
# arch/<arch>/include/uapi and arch/<arch>/include/generated/uapi are
# exported.
# They are preprocessed to remove __KERNEL__ section of the file.
#
# ==========================================================================

PHONY := __headers
__headers:

include scripts/Kbuild.include

srcdir        := $(srctree)/$(obj)

# When make is run under a fakechroot environment, the function
# $(wildcard $(srcdir)/*/.) doesn't only return directories, but also regular
# files. So, we are using a combination of sort/dir/wildcard which works
# with fakechroot.
subdirs       := $(patsubst $(srcdir)/%/,%,\
		 $(filter-out $(srcdir)/,\
		 $(sort $(dir $(wildcard $(srcdir)/*/)))))

# Recursion
__headers: $(subdirs)

.PHONY: $(subdirs)
$(subdirs):
	$(Q)$(MAKE) $(hdr-inst)=$(obj)/$@ dst=$(dst)/$@

# Skip header install/check for include/uapi and arch/$(hdr-arch)/include/uapi.
# We have only sub-directories there.
skip-inst := $(if $(filter %/uapi,$(obj)),1)

ifeq ($(skip-inst),)

# Kbuild file is optional
kbuild-file := $(srctree)/$(obj)/Kbuild
-include $(kbuild-file)

installdir    := $(INSTALL_HDR_PATH)/$(dst)
gendir        := $(objtree)/$(subst include/,include/generated/,$(obj))
header-files  := $(notdir $(wildcard $(srcdir)/*.h))
header-files  += $(notdir $(wildcard $(srcdir)/*.agh))
header-files  := $(filter-out $(no-export-headers), $(header-files))
genhdr-files  := $(notdir $(wildcard $(gendir)/*.h))
genhdr-files  := $(filter-out $(header-files), $(genhdr-files))

# files used to track state of install/check
install-file  := $(installdir)/.install
check-file    := $(installdir)/.check

# all headers files for this dir
all-files     := $(header-files) $(genhdr-files)
output-files  := $(addprefix $(installdir)/, $(all-files))

ifneq ($(mandatory-y),)
missing       := $(filter-out $(all-files),$(mandatory-y))
ifneq ($(missing),)
$(error Some mandatory headers ($(missing)) are missing in $(obj))
endif
endif

# Work out what needs to be removed
oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
unwanted      := $(filter-out $(all-files),$(oldheaders))

# Prefix unwanted with full paths to $(INSTALL_HDR_PATH)
unwanted-file := $(addprefix $(installdir)/, $(unwanted))

printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))

quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                            file$(if $(word 2, $(all-files)),s))
      cmd_install = \
        $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-files); \
        $(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-files); \
        touch $@

quiet_cmd_remove = REMOVE  $(unwanted)
      cmd_remove = rm -f $(unwanted-file)

quiet_cmd_check = CHECK   $(printdir) ($(words $(all-files)) files)
# Headers list can be pretty long, xargs helps to avoid
# the "Argument list too long" error.
      cmd_check = for f in $(all-files); do                          \
                  echo "$(installdir)/$${f}"; done                      \
                  | xargs                                            \
                  $(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \
	          touch $@

ifndef HDRCHECK
# Rules for installing headers
__headers: $(install-file)
	@:

targets += $(install-file)
$(install-file): scripts/headers_install.sh \
		 $(addprefix $(srcdir)/,$(header-files)) \
		 $(addprefix $(gendir)/,$(genhdr-files)) FORCE
	$(if $(unwanted),$(call cmd,remove),)
	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
	$(call if_changed,install)

else
__headers: $(check-file)
	@:

targets += $(check-file)
$(check-file): scripts/headers_check.pl $(output-files) FORCE
	$(call if_changed,check)

endif

targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard \
             $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

ifneq ($(cmd_files),)
	include $(cmd_files)
endif

endif # skip-inst

.PHONY: $(PHONY)
PHONY += FORCE
FORCE: ;
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