Date: Mon, 2 Mar 2020 21:02:15 -0800 From: Kees Cook <keescook@...omium.org> To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Thomas Garnier <thgarnie@...omium.org> Cc: kernel-hardening@...ts.openwall.com, kristen@...ux.intel.com, Herbert Xu <herbert@...dor.apana.org.au>, "David S. Miller" <davem@...emloft.net>, "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org, Andy Lutomirski <luto@...nel.org>, Juergen Gross <jgross@...e.com>, Thomas Hellstrom <thellstrom@...are.com>, "VMware, Inc." <pv-drivers@...are.com>, "Rafael J. Wysocki" <rjw@...ysocki.net>, Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>, Rasmus Villemoes <linux@...musvillemoes.dk>, Peter Zijlstra <peterz@...radead.org>, Miguel Ojeda <miguel.ojeda.sandonis@...il.com>, Will Deacon <will@...nel.org>, Ard Biesheuvel <ardb@...nel.org>, Masami Hiramatsu <mhiramat@...nel.org>, Jiri Slaby <jslaby@...e.cz>, Boris Ostrovsky <boris.ostrovsky@...cle.com>, Josh Poimboeuf <jpoimboe@...hat.com>, Cao jin <caoj.fnst@...fujitsu.com>, Allison Randal <allison@...utok.net>, linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org, virtualization@...ts.linux-foundation.org, linux-pm@...r.kernel.org Subject: Re: [PATCH v11 00/11] x86: PIE support to extend KASLR randomization On Thu, Feb 27, 2020 at 04:00:45PM -0800, Thomas Garnier wrote: > Minor changes based on feedback and rebase from v10. > > Splitting the previous serie in two. This part contains assembly code > changes required for PIE but without any direct dependencies with the > rest of the patchset. > > Note: Using objtool to detect non-compliant PIE relocations is not yet > possible as this patchset only includes the simplest PIE changes. > Additional changes are needed in kvm, xen and percpu code. > > Changes: > - patch v11 (assembly); > - Fix comments on x86/entry/64. > - Remove KASLR PIE explanation on all commits. > - Add note on objtool not being possible at this stage of the patchset. This moves us closer to PIE in a clean first step. I think these patches look good to go, and unblock the work in kvm, xen, and percpu code. Can one of the x86 maintainers pick this series up? Thanks! -Kees > - patch v10 (assembly): > - Swap rax for rdx on entry/64 changes based on feedback. > - Addressed feedback from Borislav Petkov on boot, paravirt, alternatives > and globally. > - Rebased the patchset and ensure it works with large kaslr (not included). > - patch v9 (assembly): > - Moved to relative reference for sync_core based on feedback. > - x86/crypto had multiple algorithms deleted, removed PIE changes to them. > - fix typo on comment end line. > - patch v8 (assembly): > - Fix issues in crypto changes (thanks to Eric Biggers). > - Remove unnecessary jump table change. > - Change author and signoff to chromium email address. > - patch v7 (assembly): > - Split patchset and reorder changes. > - patch v6: > - Rebase on latest changes in jump tables and crypto. > - Fix wording on couple commits. > - Revisit checkpatch warnings. > - Moving to @chromium.org. > - patch v5: > - Adapt new crypto modules for PIE. > - Improve per-cpu commit message. > - Fix xen 32-bit build error with .quad. > - Remove extra code for ftrace. > - patch v4: > - Simplify early boot by removing global variables. > - Modify the mcount location script for __mcount_loc intead of the address > read in the ftrace implementation. > - Edit commit description to explain better where the kernel can be located. > - Streamlined the testing done on each patch proposal. Always testing > hibernation, suspend, ftrace and kprobe to ensure no regressions. > - patch v3: > - Update on message to describe longer term PIE goal. > - Minor change on ftrace if condition. > - Changed code using xchgq. > - patch v2: > - Adapt patch to work post KPTI and compiler changes > - Redo all performance testing with latest configs and compilers > - Simplify mov macro on PIE (MOVABS now) > - Reduce GOT footprint > - patch v1: > - Simplify ftrace implementation. > - Use gcc mstack-protector-guard-reg=%gs with PIE when possible. > - rfc v3: > - Use --emit-relocs instead of -pie to reduce dynamic relocation space on > mapped memory. It also simplifies the relocation process. > - Move the start the module section next to the kernel. Remove the need for > -mcmodel=large on modules. Extends module space from 1 to 2G maximum. > - Support for XEN PVH as 32-bit relocations can be ignored with > --emit-relocs. > - Support for GOT relocations previously done automatically with -pie. > - Remove need for dynamic PLT in modules. > - Support dymamic GOT for modules. > - rfc v2: > - Add support for global stack cookie while compiler default to fs without > mcmodel=kernel > - Change patch 7 to correctly jump out of the identity mapping on kexec load > preserve. > > These patches make some of the changes necessary to build the kernel as > Position Independent Executable (PIE) on x86_64. Another patchset will > add the PIE option and larger architecture changes. PIE allows the kernel to be > placed below the 0xffffffff80000000 increasing the range of KASLR. > > The patches: > - 1, 3-11: Change in assembly code to be PIE compliant. > - 2: Add a new _ASM_MOVABS macro to fetch a symbol address generically. > > diffstat: > crypto/aegis128-aesni-asm.S | 6 +- > crypto/aesni-intel_asm.S | 8 +-- > crypto/aesni-intel_avx-x86_64.S | 3 - > crypto/camellia-aesni-avx-asm_64.S | 42 +++++++-------- > crypto/camellia-aesni-avx2-asm_64.S | 44 ++++++++-------- > crypto/camellia-x86_64-asm_64.S | 8 +-- > crypto/cast5-avx-x86_64-asm_64.S | 50 ++++++++++-------- > crypto/cast6-avx-x86_64-asm_64.S | 44 +++++++++------- > crypto/des3_ede-asm_64.S | 96 ++++++++++++++++++++++++------------ > crypto/ghash-clmulni-intel_asm.S | 4 - > crypto/glue_helper-asm-avx.S | 4 - > crypto/glue_helper-asm-avx2.S | 6 +- > crypto/sha256-avx2-asm.S | 18 ++++-- > entry/entry_64.S | 16 ++++-- > include/asm/alternative.h | 6 +- > include/asm/asm.h | 1 > include/asm/bug.h | 2 > include/asm/paravirt_types.h | 32 ++++++++++-- > include/asm/pm-trace.h | 2 > include/asm/processor.h | 6 +- > kernel/acpi/wakeup_64.S | 31 ++++++----- > kernel/head_64.S | 15 +++-- > kernel/relocate_kernel_64.S | 2 > power/hibernate_asm_64.S | 4 - > 24 files changed, 268 insertions(+), 182 deletions(-) > > Patchset is based on next-20200227. > > -- Kees Cook
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