Re: [PATCH 00/42] x86: updated patches for kaslr and setup_data etc for v4.3

[Baoquan He]

On 02/08/16 at 08:31pm, Kees Cook wrote:
> On Sat, Feb 6, 2016 at 3:50 AM, Baoquan He <bhe@xxxxxxxxxx> wrote:
> > Hi,
> >
> > Recently people using big box servers are also very interested in kaslr and want
> > to have it to enhance security. So allowing kaslr be able to randomize above 4G
> > makes much sense for different kinds of system. I would like to repost patches
> > realted to kaslr in this patchset, and leave the rest to Yinghai. Or I can try
> > to understand and adjust the rest with yh and reviewers' help, then post. But
> > firstly I will focus on kaslr and try to make it merge into Linus's tree.
> >
> > Since this patchset includes too many issues and people usually like reviewing
> > post which takes care of one main issue in one thread, I will start from below
> > thread. It mainly includes kaslr above 4G support and bug fixes and several clean
> > up patch.
> >
> > x86, boot: kaslr cleanup and 64bit kaslr support
> > https://lwn.net/Articles/637115/
> >
> > The following patch lists is taken from yh's cover letter of above patch thread.
> >
> > **************************
> > My plan is split them into
> > 1) kaslr above 4G support
> >   x86, boot: Split kernel_ident_mapping_init to another file
> >   x86, 64bit: Set ident_mapping for kaslr
> >   x86, boot: Add checking for memcpy
> >   x86, boot: Move z_extract_offset calculation to header.S
> >   x86, boot: Simplify run_size calculation
> >   x86, kaslr: Kill not used run_size related code.
> >   x86, kaslr: Use output_run_size
> >   x86, kaslr: Fix a bug that relocation can not be handled when kernel is loaded above 2G
> >   x86, kaslr: Introduce struct slot_area to manage randomization slot info
> >   x86, kaslr: Add two functions which will be used later
> >   x86, kaslr: Introduce fetch_random_virt_offset to randomize the kernel text mapping address
> >   x86, kaslr: Randomize physical and virtual address of kernel separately
> >   x86, kaslr: Add support of kernel physical address randomization above 4G
> >   x86, kaslr: Remove useless codes
> > 2) allow kaslr to choose slots below loaded address
> >   x86, kaslr: Consolidate mem_avoid array filling
> >   x86, kaslr: Allow random address could be below loaded address
> > 3) Make data from decompress_kernel stage live longer (bug fix)
> >   x86, boot: Make data from decompress_kernel stage live longer
> > 4) Get correct max_addr for relocs pointer (improvement)
> >   x86, kaslr: Get correct max_addr for relocs pointer
> >
> > The 2) could be added into 1) post. I take it out because the mem_avoid issue is very
> > complicated, can be discussed in a separate thread. And 1) post only focus the kaslr
> > above 4G support.
> >
> > That's all I plan to do. Suggestion or comments are welcome.
> 
> That sounds great, thanks! Please check the rest of the thread where I
> asked a number of questions that remain unanswered. If we can get some
> clarification on those points, I think it would help move this along
> more quickly.

Hi Kees,

Thanks for your suggestion. I am trying to understand all patches and
make some adjustment, meanwhile adjust patch log with my understanding.
And your questions help me understand it deeper. I will post after
updating. Hope you, Yinghai and other experts can help review and give
precious comments and suggestions.

Thanks
Baoquan

> 
> -Kees
> 
> >
> > Thanks
> > Baoquan
> >
> > ----- Original Message -----
> > From: "Kees Cook" <keescook@xxxxxxxxxxxx>
> > To: "Yinghai Lu" <yinghai@xxxxxxxxxx>
> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>, "Baoquan He" <bhe@xxxxxxxxxx>, "LKML" <linux-kernel@xxxxxxxxxxxxxxx>
> > Sent: Saturday, October 3, 2015 4:16:40 AM
> > Subject: Re: [PATCH 00/42] x86: updated patches for kaslr and setup_data etc for v4.3
> >
> > Hi,
> >
> > Has there been any more work on these series of patches? I asked many
> > questions in my earlier review, but nothing was answered.
> >
> > Thanks,
> >
> > -Kees
> >
> > On Tue, Jul 7, 2015 at 4:21 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >> On Tue, Jul 7, 2015 at 1:19 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> >>> Those patches are rebased on v4.2-rc1 that I sent before but were rejected
> >>> by Ingo on changelog.
> >>>
> >>> Kees Cook said that he would like to give a try to make improvement on changelog
> >>> to get things moving.
> >>
> >> Thanks for working on this! I think it might be best to split this
> >> long series into shorter ones. It seems like there are several areas:
> >>
> >> - fixing kASLR
> >> - extended kASLR above 4G
> >> - setup_data cleanup
> >> - various other cleanups
> >>
> >> It might make sense to keep them separate for easier review?
> >>
> >> -Kees
> >>
> >>>
> >>> First part are kaslr related:
> >>> 1. First put compressed kernel ZO near end of the buffer before decompressing
> >>> so we can find the ZO position easily for kaslr buffer searchin
> >>> 2. kill run_size calculation shell scripts.
> >>> 3. create new ident mapping for kasl 64bit, so we can cover
> >>>    above 4G random kernel base
> >>> 4. 7 patches from He that support random random, as I already used his patches
> >>>    to test the ident mapping code.
> >>> 5. some debug patches for boot/kaslr.
> >>>
> >>> Second part are setup_data related:
> >>> Now setup_data is reserved via memblock and e820 and different
> >>> handlers have different ways, and it is confusing.
> >>> 1. SETUP_E820_EXT: is consumed early and will not copy or access again.
> >>>         have memory wasted.
> >>> 2. SETUP_EFI: is accessed via ioremap every time at early stage.
> >>>         have memory wasted.
> >>> 3. SETUP_DTB: is copied locally.
> >>>         have memory wasted.
> >>> 4. SETUP_PCI: is accessed via ioremap for every pci devices, even run-time.
> >>> Also setup_data is exported to debugfs for debug purpose.
> >>> Here will convert to let every handler to decide how to handle it.
> >>> and will not reserve the setup_data generally, so will not
> >>> waste memory and also make memblock/e820 keep page aligned.
> >>> 1. not touch E820 anymore.
> >>> 2. copy SETUP_EFI to __initdata variable and access it without ioremap.
> >>> 3. SETUP_DTB: reserver and copy to local and free.
> >>> 4. SETUP_PCI: reverve localy and convert to list, to avoid keeping ioremap.
> >>> 5. export SETUP_PCI via sysfs.
> >>>
> >>> Third part are some small cleanup patches.
> >>>
> >>> put those patches at
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-x86-v4.3-next
> >>>
> >>> Thanks
> >>>
> >>> Yinghai
> >>>
> >>>
> >>> Baoquan He (7):
> >>>   x86, kaslr: Fix a bug that relocation can not be handled when kernel is loaded above 2G
> >>>   x86, kaslr: Introduce struct slot_area to manage randomization slot info
> >>>   x86, kaslr: Add two functions which will be used later
> >>>   x86, kaslr: Introduce fetch_random_virt_offset to randomize the kernel text mapping address
> >>>   x86, kaslr: Randomize physical and virtual address of kernel separately
> >>>   x86, kaslr: Add support of kernel physical address randomization above 4G
> >>>   x86, kaslr: Remove useless codes
> >>>
> >>> Yinghai Lu (35):
> >>>   x86, kasl: Remove not needed parameter for choose_kernel_location
> >>>   x86, boot: Move compressed kernel to end of buffer before decompressing
> >>>   x86, boot: Fix run_size calculation
> >>>   x86, kaslr: Kill not needed and wrong run_size calculation code.
> >>>   x86, kaslr: rename output_size to output_run_size
> >>>   x86, kaslr: Consolidate mem_avoid array filling
> >>>   x86, boot: Move z_extract_offset calculation to header.S
> >>>   x86, kaslr: Get correct max_addr for relocs pointer
> >>>   x86, boot: Split kernel_ident_mapping_init to another file
> >>>   x86, 64bit: Set ident_mapping for kaslr
> >>>   x86, boot: Add checking for memcpy
> >>>   x86, kaslr: Allow random address could be below loaded address
> >>>   x86, boot: Add printf support for early console in compressed/misc.c
> >>>   x86, boot: Add more debug printout in compressed/misc.c
> >>>   x86, setup: Check early serial console per string instead of one char
> >>>   x86, setup: Use puts() instead of printf() in edd code
> >>>   x86: Setup early console as early as possible in x86_start_kernel()
> >>>   x86, boot: print compression suffix in decompress stage
> >>>   x86: remove not needed clear_page calling
> >>>   x86: restore end_of_ram to E820_RAM
> >>>   x86, boot: Allow 64bit EFI kernel to be loaded above 4G
> >>>   x86: Find correct 64 bit ramdisk address for microcode early update
> >>>   x86: Kill E820_RESERVED_KERN
> >>>   x86, efi: Copy SETUP_EFI data and access directly
> >>>   x86, of: Let add_dtb reserve setup_data locally
> >>>   x86, boot: Add add_pci handler for SETUP_PCI
> >>>   x86: Kill not used setup_data handling code
> >>>   x86, boot, PCI: Convert SETUP_PCI data to list
> >>>   x86, boot, PCI: Copy SETUP_PCI rom to kernel space
> >>>   x86, boot, PCI: Export SETUP_PCI data via sysfs
> >>>   x86: Fix typo in mark_rodata_ro
> >>>   x86, 64bit: add pfn_range_is_highmapped()
> >>>   x86, 64bit: remove highmap for not needed ranges
> >>>   x86, 64bit: Add __pa_high/__va_high
> >>>   x86: fix msr print again
> >>>
> >>>  Documentation/x86/boot.txt                  |  19 ++
> >>>  arch/x86/boot/Makefile                      |  13 +-
> >>>  arch/x86/boot/compressed/Makefile           |  21 +-
> >>>  arch/x86/boot/compressed/aslr.c             | 258 ++++++++++++++++-------
> >>>  arch/x86/boot/compressed/eboot.c            |  15 +-
> >>>  arch/x86/boot/compressed/head_32.S          |  14 +-
> >>>  arch/x86/boot/compressed/head_64.S          |  22 +-
> >>>  arch/x86/boot/compressed/misc.c             | 129 +++++++++---
> >>>  arch/x86/boot/compressed/misc.h             |  41 +++-
> >>>  arch/x86/boot/compressed/misc_pgt.c         |  91 ++++++++
> >>>  arch/x86/boot/compressed/mkpiggy.c          |  28 +--
> >>>  arch/x86/boot/compressed/printf.c           |   5 +
> >>>  arch/x86/boot/compressed/string.c           |  28 ++-
> >>>  arch/x86/boot/compressed/vmlinux.lds.S      |   1 +
> >>>  arch/x86/boot/edd.c                         |   4 +-
> >>>  arch/x86/boot/header.S                      |  34 ++-
> >>>  arch/x86/boot/tty.c                         |  14 +-
> >>>  arch/x86/include/asm/boot.h                 |  19 ++
> >>>  arch/x86/include/asm/efi.h                  |   2 +-
> >>>  arch/x86/include/asm/page.h                 |   5 +
> >>>  arch/x86/include/asm/pci.h                  |   4 +
> >>>  arch/x86/include/asm/pgtable_64.h           |   2 +
> >>>  arch/x86/include/asm/processor.h            |   1 -
> >>>  arch/x86/include/asm/prom.h                 |   9 +-
> >>>  arch/x86/include/asm/setup.h                |   5 +
> >>>  arch/x86/include/uapi/asm/bootparam.h       |   1 +
> >>>  arch/x86/include/uapi/asm/e820.h            |   8 -
> >>>  arch/x86/kernel/asm-offsets.c               |   2 +
> >>>  arch/x86/kernel/cpu/common.c                |  61 +++---
> >>>  arch/x86/kernel/cpu/microcode/amd_early.c   |  10 +-
> >>>  arch/x86/kernel/cpu/microcode/intel_early.c |   8 +-
> >>>  arch/x86/kernel/devicetree.c                |  39 ++--
> >>>  arch/x86/kernel/e820.c                      |  18 +-
> >>>  arch/x86/kernel/head.c                      |  26 +++
> >>>  arch/x86/kernel/head32.c                    |   1 +
> >>>  arch/x86/kernel/head64.c                    |  21 +-
> >>>  arch/x86/kernel/kdebugfs.c                  | 142 -------------
> >>>  arch/x86/kernel/setup.c                     |  79 ++-----
> >>>  arch/x86/kernel/tboot.c                     |   3 +-
> >>>  arch/x86/kernel/vmlinux.lds.S               |   1 +
> >>>  arch/x86/mm/ident_map.c                     |  74 +++++++
> >>>  arch/x86/mm/init_64.c                       | 173 +++++++--------
> >>>  arch/x86/mm/pageattr.c                      |  16 +-
> >>>  arch/x86/pci/common.c                       | 313 ++++++++++++++++++++++++++--
> >>>  arch/x86/platform/efi/efi.c                 |  13 +-
> >>>  arch/x86/platform/efi/efi_64.c              |  10 +-
> >>>  arch/x86/platform/efi/quirks.c              |  23 +-
> >>>  arch/x86/tools/calc_run_size.sh             |  42 ----
> >>>  drivers/tty/serial/8250/8250_early.c        |  17 ++
> >>>  kernel/printk/printk.c                      |  11 +-
> >>>  50 files changed, 1235 insertions(+), 661 deletions(-)
> >>>  create mode 100644 arch/x86/boot/compressed/misc_pgt.c
> >>>  create mode 100644 arch/x86/boot/compressed/printf.c
> >>>  create mode 100644 arch/x86/mm/ident_map.c
> >>>  delete mode 100644 arch/x86/tools/calc_run_size.sh
> >>>
> >>> --
> >>> 1.8.4.5
> >>>
> >>
> >>
> >>
> >> --
> >> Kees Cook
> >> Chrome OS Security
> >
> >
> >
> > --
> > Kees Cook
> > Chrome OS Security
> > --
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> 
> 
> 
> -- 
> Kees Cook
> Chrome OS & Brillo Security