[PATCH v2 00/29] vmlinux.lds.h: Refactor EXCEPTION_TABLE and NOTES

Kees Cook
2019-10-11T00:05:40Z

Arch maintainers: please send Acks (if you haven't already) for your
respective linker script changes; the intention is for this series to
land via -tip.

v1: https://lore.kernel.org/lkml/20190926175602.33098-1-keescook@chromium.org
v2: clean up commit messages, rename RO_EXCEPTION_TABLE (bp)

This series works to move the linker sections for NOTES and
EXCEPTION_TABLE into the RO_DATA area, where they belong on most
(all?) architectures. The problem being addressed was the discovery
by Rick Edgecombe that the exception table was accidentally marked
executable while he was developing his execute-only-memory series. When
permissions were flipped from readable-and-executable to only-executable,
the exception table became unreadable, causing things to explode rather
badly. :)

Roughly speaking, the steps are:

- regularize the linker names for PT_NOTE and PT_LOAD program headers
(to "note" and "text" respectively)
- regularize restoration of linker section to program header assignment
(when PT_NOTE exists)
- move NOTES into RO_DATA
- finish macro naming conversions for RO_DATA and RW_DATA
- move EXCEPTION_TABLE into RO_DATA on architectures where this is clear
- clean up some x86-specific reporting of kernel memory resources
- switch x86 linker fill byte from x90 (NOP) to 0xcc (INT3), just because
I finally realized what that trailing ": 0x9090" meant -- and we should
trap, not slide, if execution lands in section padding

Thanks!

-Kees

Kees Cook (29):
powerpc: Rename "notes" PT_NOTE to "note"
powerpc: Remove PT_NOTE workaround
powerpc: Rename PT_LOAD identifier "kernel" to "text"
alpha: Rename PT_LOAD identifier "kernel" to "text"
ia64: Rename PT_LOAD identifier "code" to "text"
s390: Move RO_DATA into "text" PT_LOAD Program Header
x86: Restore "text" Program Header with dummy section
vmlinux.lds.h: Provide EMIT_PT_NOTE to indicate export of .notes
vmlinux.lds.h: Move Program Header restoration into NOTES macro
vmlinux.lds.h: Move NOTES into RO_DATA
vmlinux.lds.h: Replace RODATA with RO_DATA
vmlinux.lds.h: Replace RO_DATA_SECTION with RO_DATA
vmlinux.lds.h: Replace RW_DATA_SECTION with RW_DATA
vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
x86: Actually use _etext for end of text segment
x86: Move EXCEPTION_TABLE to RO_DATA segment
alpha: Move EXCEPTION_TABLE to RO_DATA segment
arm64: Move EXCEPTION_TABLE to RO_DATA segment
c6x: Move EXCEPTION_TABLE to RO_DATA segment
h8300: Move EXCEPTION_TABLE to RO_DATA segment
ia64: Move EXCEPTION_TABLE to RO_DATA segment
microblaze: Move EXCEPTION_TABLE to RO_DATA segment
parisc: Move EXCEPTION_TABLE to RO_DATA segment
powerpc: Move EXCEPTION_TABLE to RO_DATA segment
xtensa: Move EXCEPTION_TABLE to RO_DATA segment
x86/mm: Remove redundant &s on addresses
x86/mm: Report which part of kernel image is freed
x86/mm: Report actual image regions in /proc/iomem
x86: Use INT3 instead of NOP for linker fill bytes

arch/alpha/kernel/vmlinux.lds.S | 18 +++++-----
arch/arc/kernel/vmlinux.lds.S | 6 ++--
arch/arm/kernel/vmlinux-xip.lds.S | 4 +--
arch/arm/kernel/vmlinux.lds.S | 4 +--
arch/arm64/kernel/vmlinux.lds.S | 9 ++---
arch/c6x/kernel/vmlinux.lds.S | 8 ++---
arch/csky/kernel/vmlinux.lds.S | 5 ++-
arch/h8300/kernel/vmlinux.lds.S | 9 ++---
arch/hexagon/kernel/vmlinux.lds.S | 5 ++-
arch/ia64/kernel/vmlinux.lds.S | 20 +++++------
arch/m68k/kernel/vmlinux-nommu.lds | 4 +--
arch/m68k/kernel/vmlinux-std.lds | 2 +-
arch/m68k/kernel/vmlinux-sun3.lds | 2 +-
arch/microblaze/kernel/vmlinux.lds.S | 8 ++---
arch/mips/kernel/vmlinux.lds.S | 15 ++++----
arch/nds32/kernel/vmlinux.lds.S | 5 ++-
arch/nios2/kernel/vmlinux.lds.S | 5 ++-
arch/openrisc/kernel/vmlinux.lds.S | 7 ++--
arch/parisc/kernel/vmlinux.lds.S | 11 +++---
arch/powerpc/kernel/vmlinux.lds.S | 37 ++++---------------
arch/riscv/kernel/vmlinux.lds.S | 5 ++-
arch/s390/kernel/vmlinux.lds.S | 12 +++----
arch/sh/kernel/vmlinux.lds.S | 3 +-
arch/sparc/kernel/vmlinux.lds.S | 3 +-
arch/um/include/asm/common.lds.S | 3 +-
arch/unicore32/kernel/vmlinux.lds.S | 5 ++-
arch/x86/include/asm/processor.h | 2 +-
arch/x86/include/asm/sections.h | 1 -
arch/x86/kernel/setup.c | 12 ++++++-
arch/x86/kernel/vmlinux.lds.S | 16 ++++-----
arch/x86/mm/init.c | 8 ++---
arch/x86/mm/init_64.c | 16 +++++----
arch/x86/mm/pti.c | 2 +-
arch/xtensa/kernel/vmlinux.lds.S | 8 ++---
include/asm-generic/vmlinux.lds.h | 53 ++++++++++++++++++++--------
35 files changed, 159 insertions(+), 174 deletions(-)

--
2.17.1

Kees Cook (29):
powerpc: Rename "notes" PT_NOTE to "note"
powerpc: Remove PT_NOTE workaround
powerpc: Rename PT_LOAD identifier "kernel" to "text"
alpha: Rename PT_LOAD identifier "kernel" to "text"
ia64: Rename PT_LOAD identifier "code" to "text"
s390: Move RO_DATA into "text" PT_LOAD Program Header
x86: Restore "text" Program Header with dummy section
vmlinux.lds.h: Provide EMIT_PT_NOTE to indicate export of .notes
vmlinux.lds.h: Move Program Header restoration into NOTES macro
vmlinux.lds.h: Move NOTES into RO_DATA
vmlinux.lds.h: Replace RODATA with RO_DATA
vmlinux.lds.h: Replace RO_DATA_SECTION with RO_DATA
vmlinux.lds.h: Replace RW_DATA_SECTION with RW_DATA
vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
x86: Actually use _etext for end of text segment
x86: Move EXCEPTION_TABLE to RO_DATA segment
alpha: Move EXCEPTION_TABLE to RO_DATA segment
arm64: Move EXCEPTION_TABLE to RO_DATA segment
c6x: Move EXCEPTION_TABLE to RO_DATA segment
h8300: Move EXCEPTION_TABLE to RO_DATA segment
ia64: Move EXCEPTION_TABLE to RO_DATA segment
microblaze: Move EXCEPTION_TABLE to RO_DATA segment
parisc: Move EXCEPTION_TABLE to RO_DATA segment
powerpc: Move EXCEPTION_TABLE to RO_DATA segment
xtensa: Move EXCEPTION_TABLE to RO_DATA segment
x86/mm: Remove redundant &s on addresses
x86/mm: Report which part of kernel image is freed
x86/mm: Report actual image regions in /proc/iomem
x86: Use INT3 instead of NOP for linker fill bytes

arch/alpha/kernel/vmlinux.lds.S | 18 +++++-----
arch/arc/kernel/vmlinux.lds.S | 6 ++--
arch/arm/kernel/vmlinux-xip.lds.S | 4 +--
arch/arm/kernel/vmlinux.lds.S | 4 +--
arch/arm64/kernel/vmlinux.lds.S | 10 +++---
arch/c6x/kernel/vmlinux.lds.S | 8 ++---
arch/csky/kernel/vmlinux.lds.S | 5 ++-
arch/h8300/kernel/vmlinux.lds.S | 9 ++---
arch/hexagon/kernel/vmlinux.lds.S | 5 ++-
arch/ia64/kernel/vmlinux.lds.S | 20 +++++------
arch/m68k/kernel/vmlinux-nommu.lds | 4 +--
arch/m68k/kernel/vmlinux-std.lds | 2 +-
arch/m68k/kernel/vmlinux-sun3.lds | 2 +-
arch/microblaze/kernel/vmlinux.lds.S | 8 ++---
arch/mips/kernel/vmlinux.lds.S | 15 ++++----
arch/nds32/kernel/vmlinux.lds.S | 5 ++-
arch/nios2/kernel/vmlinux.lds.S | 5 ++-
arch/openrisc/kernel/vmlinux.lds.S | 7 ++--
arch/parisc/kernel/vmlinux.lds.S | 11 +++---
arch/powerpc/kernel/vmlinux.lds.S | 37 ++++---------------
arch/riscv/kernel/vmlinux.lds.S | 5 ++-
arch/s390/kernel/vmlinux.lds.S | 12 +++----
arch/sh/kernel/vmlinux.lds.S | 3 +-
arch/sparc/kernel/vmlinux.lds.S | 3 +-
arch/um/include/asm/common.lds.S | 3 +-
arch/unicore32/kernel/vmlinux.lds.S | 5 ++-
arch/x86/include/asm/processor.h | 2 +-
arch/x86/include/asm/sections.h | 1 -
arch/x86/kernel/setup.c | 12 ++++++-
arch/x86/kernel/vmlinux.lds.S | 16 ++++-----
arch/x86/mm/init.c | 8 ++---
arch/x86/mm/init_64.c | 16 +++++----
arch/x86/mm/pti.c | 2 +-
arch/xtensa/kernel/vmlinux.lds.S | 8 ++---
include/asm-generic/vmlinux.lds.h | 53 ++++++++++++++++++++--------
35 files changed, 159 insertions(+), 175 deletions(-)

--
2.17.1