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2021-01-30x86/boot/compressed: Disable relocation relaxationArvind Sankar1-0/+2
commit 09e43968db40c33a73e9ddbfd937f46d5c334924 upstream. The x86-64 psABI [0] specifies special relocation types (R_X86_64_[REX_]GOTPCRELX) for indirection through the Global Offset Table, semantically equivalent to R_X86_64_GOTPCREL, which the linker can take advantage of for optimization (relaxation) at link time. This is supported by LLD and binutils versions 2.26 onwards. The compressed kernel is position-independent code, however, when using LLD or binutils versions before 2.27, it must be linked without the -pie option. In this case, the linker may optimize certain instructions into a non-position-independent form, by converting foo@GOTPCREL(%rip) to $foo. This potential issue has been present with LLD and binutils-2.26 for a long time, but it has never manifested itself before now: - LLD and binutils-2.26 only relax movq foo@GOTPCREL(%rip), %reg to leaq foo(%rip), %reg which is still position-independent, rather than mov $foo, %reg which is permitted by the psABI when -pie is not enabled. - GCC happens to only generate GOTPCREL relocations on mov instructions. - CLang does generate GOTPCREL relocations on non-mov instructions, but when building the compressed kernel, it uses its integrated assembler (due to the redefinition of KBUILD_CFLAGS dropping -no-integrated-as), which has so far defaulted to not generating the GOTPCRELX relocations. Nick Desaulniers reports [1,2]: "A recent change [3] to a default value of configuration variable (ENABLE_X86_RELAX_RELOCATIONS OFF -> ON) in LLVM now causes Clang's integrated assembler to emit R_X86_64_GOTPCRELX/R_X86_64_REX_GOTPCRELX relocations. LLD will relax instructions with these relocations based on whether the image is being linked as position independent or not. When not, then LLD will relax these instructions to use absolute addressing mode (R_RELAX_GOT_PC_NOPIC). This causes kernels built with Clang and linked with LLD to fail to boot." Patch series [4] is a solution to allow the compressed kernel to be linked with -pie unconditionally, but even if merged is unlikely to be backported. As a simple solution that can be applied to stable as well, prevent the assembler from generating the relaxed relocation types using the -mrelax-relocations=no option. For ease of backporting, do this unconditionally. [0] https://gitlab.com/x86-psABIs/x86-64-ABI/-/blob/master/x86-64-ABI/linker-optimization.tex#L65 [1] https://lore.kernel.org/lkml/20200807194100.3570838-1-ndesaulniers@google.com/ [2] https://github.com/ClangBuiltLinux/linux/issues/1121 [3] https://reviews.llvm.org/rGc41a18cf61790fc898dcda1055c3efbf442c14c0 [4] https://lore.kernel.org/lkml/20200731202738.2577854-1-nivedita@alum.mit.edu/ Reported-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200812004308.1448603-1-nivedita@alum.mit.edu [nc: Backport to 4.9] Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20x86/boot: Correct relocation destination on old linkersArvind Sankar2-2/+4
[ Upstream commit 5214028dd89e49ba27007c3ee475279e584261f0 ] For the 32-bit kernel, as described in 6d92bc9d483a ("x86/build: Build compressed x86 kernels as PIE"), pre-2.26 binutils generates R_386_32 relocations in PIE mode. Since the startup code does not perform relocation, any reloc entry with R_386_32 will remain as 0 in the executing code. Commit 974f221c84b0 ("x86/boot: Move compressed kernel to the end of the decompression buffer") added a new symbol _end but did not mark it hidden, which doesn't give the correct offset on older linkers. This causes the compressed kernel to be copied beyond the end of the decompression buffer, rather than flush against it. This region of memory may be reserved or already allocated for other purposes by the bootloader. Mark _end as hidden to fix. This changes the relocation from R_386_32 to R_386_RELATIVE even on the pre-2.26 binutils. For 64-bit, this is not strictly necessary, as the 64-bit kernel is only built as PIE if the linker supports -z noreloc-overflow, which implies binutils-2.27+, but for consistency, mark _end as hidden here too. The below illustrates the before/after impact of the patch using binutils-2.25 and gcc-4.6.4 (locally compiled from source) and QEMU. Disassembly before patch: 48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax 4e: 2d 00 00 00 00 sub $0x0,%eax 4f: R_386_32 _end Disassembly after patch: 48: 8b 86 60 02 00 00 mov 0x260(%esi),%eax 4e: 2d 00 f0 76 00 sub $0x76f000,%eax 4f: R_386_RELATIVE *ABS* Dump from extract_kernel before patch: early console in extract_kernel input_data: 0x0207c098 <--- this is at output + init_size input_len: 0x0074fef1 output: 0x01000000 output_len: 0x00fa63d0 kernel_total_size: 0x0107c000 needed_size: 0x0107c000 Dump from extract_kernel after patch: early console in extract_kernel input_data: 0x0190d098 <--- this is at output + init_size - _end input_len: 0x0074fef1 output: 0x01000000 output_len: 0x00fa63d0 kernel_total_size: 0x0107c000 needed_size: 0x0107c000 Fixes: 974f221c84b0 ("x86/boot: Move compressed kernel to the end of the decompression buffer") Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200207214926.3564079-1-nivedita@alum.mit.edu Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-24x86/boot: Use unsigned comparison for addressesArvind Sankar2-3/+3
[ Upstream commit 81a34892c2c7c809f9c4e22c5ac936ae673fb9a2 ] The load address is compared with LOAD_PHYSICAL_ADDR using a signed comparison currently (using jge instruction). When loading a 64-bit kernel using the new efi32_pe_entry() point added by: 97aa276579b2 ("efi/x86: Add true mixed mode entry point into .compat section") using Qemu with -m 3072, the firmware actually loads us above 2Gb, resulting in a very early crash. Use the JAE instruction to perform a unsigned comparison instead, as physical addresses should be considered unsigned. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200301230436.2246909-6-nivedita@alum.mit.edu Link: https://lore.kernel.org/r/20200308080859.21568-14-ardb@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-23x86/efistub: Disable paging at mixed mode entryArd Biesheuvel1-0/+5
commit 4911ee401b7ceff8f38e0ac597cbf503d71e690c upstream. The EFI mixed mode entry code goes through the ordinary startup_32() routine before jumping into the kernel's EFI boot code in 64-bit mode. The 32-bit startup code must be entered with paging disabled, but this is not documented as a requirement for the EFI handover protocol, and so we should disable paging explicitly when entering the kernel from 32-bit EFI firmware. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: <stable@vger.kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Hans de Goede <hdegoede@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224132909.102540-4-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-06x86, boot: Remove multiple copy of static function sanitize_boot_params()Zhenzhong Duan2-1/+1
[ Upstream commit 8c5477e8046ca139bac250386c08453da37ec1ae ] Kernel build warns: 'sanitize_boot_params' defined but not used [-Wunused-function] at below files: arch/x86/boot/compressed/cmdline.c arch/x86/boot/compressed/error.c arch/x86/boot/compressed/early_serial_console.c arch/x86/boot/compressed/acpi.c That's becausethey each include misc.h which includes a definition of sanitize_boot_params() via bootparam_utils.h. Remove the inclusion from misc.h and have the c file including bootparam_utils.h directly. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1563283092-1189-1-git-send-email-zhenzhong.duan@oracle.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-02-27x86/boot: Disable the address-of-packed-member compiler warningMatthias Kaehlcke1-0/+1
commit 20c6c189045539d29f4854d92b7ea9c329e1edfc upstream. The clang warning 'address-of-packed-member' is disabled for the general kernel code, also disable it for the x86 boot code. This suppresses a bunch of warnings like this when building with clang: ./arch/x86/include/asm/processor.h:535:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may result in an unaligned pointer value [-Waddress-of-packed-member] return this_cpu_read_stable(cpu_tss.x86_tss.sp0); ^~~~~~~~~~~~~~~~~~~ ./arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable' #define this_cpu_read_stable(var) percpu_stable_op("mov", var) ^~~ ./arch/x86/include/asm/percpu.h:228:16: note: expanded from macro 'percpu_stable_op' : "p" (&(var))); ^~~ Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Cc: Doug Anderson <dianders@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170725215053.135586-1-mka@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05x86/boot: Fix if_changed build flip/flop bugKees Cook1-2/+6
[ Upstream commit 92a4728608a8fd228c572bc8ff50dd98aa0ddf2a ] Dirk Gouders reported that two consecutive "make" invocations on an already compiled tree will show alternating behaviors: $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h LD arch/x86/boot/compressed/vmlinux ZOFFSET arch/x86/boot/zoffset.h AS arch/x86/boot/header.o LD arch/x86/boot/setup.elf OBJCOPY arch/x86/boot/setup.bin OBJCOPY arch/x86/boot/vmlinux.bin BUILD arch/x86/boot/bzImage Setup is 15644 bytes (padded to 15872 bytes). System is 6663 kB CRC 3eb90f40 Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules He bisected it back to: commit 98f78525371b ("x86/boot: Refuse to build with data relocations") The root cause was the use of the "if_changed" kbuild function multiple times for the same target. It was designed to only be used once per target, otherwise it will effectively always trigger, flipping back and forth between the two commands getting recorded by "if_changed". Instead, this patch merges the two commands into a single function to get stable build artifacts (i.e. .vmlinux.cmd), and a single build behavior. Bisected-and-Reported-by: Dirk Gouders <dirk@gouders.net> Fix-Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180724230827.GA37823@beast Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22efi: Avoid potential crashes, fix the 'struct efi_pci_io_protocol_32' ↵Ard Biesheuvel1-2/+4
definition for mixed mode commit 0b3225ab9407f557a8e20f23f37aa7236c10a9b1 upstream. Mixed mode allows a kernel built for x86_64 to interact with 32-bit EFI firmware, but requires us to define all struct definitions carefully when it comes to pointer sizes. 'struct efi_pci_io_protocol_32' currently uses a 'void *' for the 'romimage' field, which will be interpreted as a 64-bit field on such kernels, potentially resulting in bogus memory references and subsequent crashes. Tested-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: <stable@vger.kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180504060003.19618-13-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-13x86/boot: Declare error() as noreturnKees Cook1-1/+3
[ Upstream commit 60854a12d281e2fa25662fa32ac8022bbff17432 ] The compressed boot function error() is used to halt execution, but it wasn't marked with "noreturn". This fixes that in preparation for supporting kernel FORTIFY_SOURCE, which uses the noreturn annotation on panic, and calls error(). GCC would warn about a noreturn function calling a non-noreturn function: arch/x86/boot/compressed/misc.c: In function ‘fortify_panic’: arch/x86/boot/compressed/misc.c:416:1: warning: ‘noreturn’ function does return } ^ Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/20170506045116.GA2879@beast Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-28x86/boot/64: Verify alignment of the LOAD segmentH.J. Lu1-0/+4
commit c55b8550fa57ba4f5e507be406ff9fc2845713e8 upstream. Since the x86-64 kernel must be aligned to 2MB, refuse to boot the kernel if the alignment of the LOAD segment isn't a multiple of 2MB. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/CAMe9rOrR7xSJgUfiCoZLuqWUwymRxXPoGBW38%2BpN%3D9g%2ByKNhZw@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-24x86/KASLR: Fix kexec kernel boot crash when KASLR randomization failsBaoquan He1-2/+9
[ Upstream commit da63b6b20077469bd6bd96e07991ce145fc4fbc4 ] Dave found that a kdump kernel with KASLR enabled will reset to the BIOS immediately if physical randomization failed to find a new position for the kernel. A kernel with the 'nokaslr' option works in this case. The reason is that KASLR will install a new page table for the identity mapping, while it missed building it for the original kernel location if KASLR physical randomization fails. This only happens in the kexec/kdump kernel, because the identity mapping has been built for kexec/kdump in the 1st kernel for the whole memory by calling init_pgtable(). Here if physical randomizaiton fails, it won't build the identity mapping for the original area of the kernel but change to a new page table '_pgtable'. Then the kernel will triple fault immediately caused by no identity mappings. The normal kernel won't see this bug, because it comes here via startup_32() and CR3 will be set to _pgtable already. In startup_32() the identity mapping is built for the 0~4G area. In KASLR we just append to the existing area instead of entirely overwriting it for on-demand identity mapping building. So the identity mapping for the original area of kernel is still there. To fix it we just switch to the new identity mapping page table when physical KASLR succeeds. Otherwise we keep the old page table unchanged just like "nokaslr" does. Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Dave Young <dyoung@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1493278940-5885-1-git-send-email-bhe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05KPTI: Rename to PAGE_TABLE_ISOLATIONKees Cook1-1/+1
This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05kaiser: do not set _PAGE_NX on pgd_noneHugh Dickins1-0/+1
native_pgd_clear() uses native_set_pgd(), so native_set_pgd() must avoid setting the _PAGE_NX bit on an otherwise pgd_none() entry: usually that just generated a warning on exit, but sometimes more mysterious and damaging failures (our production machines could not complete booting). The original fix to this just avoided adding _PAGE_NX to an empty entry; but eventually more problems surfaced with kexec, and EFI mapping expected to be a problem too. So now instead change native_set_pgd() to update shadow only if _PAGE_USER: A few places (kernel/machine_kexec_64.c, platform/efi/efi_64.c for sure) use set_pgd() to set up a temporary internal virtual address space, with physical pages remapped at what Kaiser regards as userspace addresses: Kaiser then assumes a shadow pgd follows, which it will try to corrupt. This appears to be responsible for the recent kexec and kdump failures; though it's unclear how those did not manifest as a problem before. Ah, the shadow pgd will only be assumed to "follow" if the requested pgd is on an even-numbered page: so I suppose it was going wrong 50% of the time all along. What we need is a flag to set_pgd(), to tell it we're dealing with userspace. Er, isn't that what the pgd's _PAGE_USER bit is saying? Add a test for that. But we cannot do the same for pgd_clear() (which may be called to clear corrupted entries - set aside the question of "corrupt in which pgd?" until later), so there just rely on pgd_clear() not being called in the problematic cases - with a WARN_ON_ONCE() which should fire half the time if it is. But this is getting too big for an inline function: move it into arch/x86/mm/kaiser.c (which then demands a boot/compressed mod); and de-void and de-space native_get_shadow/normal_pgd() while here. Also make an unnecessary change to KASLR's init_trampoline(): it was using set_pgd() to assign a pgd-value to a global variable (not in a pg directory page), which was rather scary given Kaiser's previous set_pgd() implementation: not a problem now, but too scary to leave as was, it could easily blow up if we have to change set_pgd() again. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-05x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bugBaoquan He3-7/+2
commit 8eabf42ae5237e6b699aeac687b5b629e3537c8d upstream. Kernel text KASLR is separated into physical address and virtual address randomization. And for virtual address randomization, we only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE. So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR, but not the original kernel loading address 'output'. The bug will cause kernel boot failure if kernel is loaded at a different position than the address, 16M, which is decided at compiled time. Kexec/kdump is such practical case. To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial value. Tested-by: Dave Young <dyoung@redhat.com> Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately") Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-07x86/boot: Use CROSS_COMPILE prefix for readelfRob Landley1-1/+1
commit 3780578761921f094179c6289072a74b2228c602 upstream. The boot code Makefile contains a straight 'readelf' invocation. This causes build warnings in cross compile environments, when there is no unprefixed readelf accessible via $PATH. Add the missing $(CROSS_COMPILE) prefix. [ tglx: Rewrote changelog ] Fixes: 98f78525371b ("x86/boot: Refuse to build with data relocations") Signed-off-by: Rob Landley <rob@landley.net> Acked-by: Kees Cook <keescook@chromium.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Paul Bolle <pebolle@tiscali.nl> Cc: "H.J. Lu" <hjl.tools@gmail.com> Link: http://lkml.kernel.org/r/ced18878-693a-9576-a024-113ef39a22c0@landley.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-21x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as wellH.J. Lu1-3/+2
Since the bootloader may load the compressed x86 kernel at any address, it should always be built as PIE, not just when CONFIG_RELOCATABLE=y. Otherwise, linker in binutils 2.27 will optimize GOT load into the absolute address when building the compressed x86 kernel as a non-PIE executable. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org [ Small wording changes. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-13Merge tag 'efi-next' of ↵Ingo Molnar3-44/+10
git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into efi/core Pull EFI updates from Matt Fleming: "* Refactor the EFI memory map code into architecture neutral files and allow drivers to permanently reserve EFI boot services regions on x86, as well as ARM/arm64 - Matt Fleming * Add ARM support for the EFI esrt driver - Ard Biesheuvel * Make the EFI runtime services and efivar API interruptible by swapping spinlocks for semaphores - Sylvain Chouleur * Provide the EFI identity mapping for kexec which allows kexec to work on SGI/UV platforms with requiring the "noefi" kernel command line parameter - Alex Thorlton * Add debugfs node to dump EFI page tables on arm64 - Ard Biesheuvel * Merge the EFI test driver being carried out of tree until now in the FWTS project - Ivan Hu * Expand the list of flags for classifying EFI regions as "RAM" on arm64 so we align with the UEFI spec - Ard Biesheuvel * Optimise out the EFI mixed mode if it's unsupported (CONFIG_X86_32) or disabled (CONFIG_EFI_MIXED=n) and switch the early EFI boot services function table for direct calls, alleviating us from having to maintain the custom function table - Lukas Wunner * Miscellaneous cleanups and fixes" Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-09x86/efi: Allow invocation of arbitrary boot servicesLukas Wunner3-19/+8
We currently allow invocation of 8 boot services with efi_call_early(). Not included are LocateHandleBuffer and LocateProtocol in particular. For graphics output or to retrieve PCI ROMs and Apple device properties, we're thus forced to use the LocateHandle + AllocatePool + LocateHandle combo, which is cumbersome and needs more code. The ARM folks allow invocation of the full set of boot services but are restricted to our 8 boot services in functions shared across arches. Thus, rather than adding just LocateHandleBuffer and LocateProtocol to struct efi_config, let's rework efi_call_early() to allow invocation of arbitrary boot services by selecting the 64 bit vs 32 bit code path in the macro itself. When compiling for 32 bit or for 64 bit without mixed mode, the unused code path is optimized away and the binary code is the same as before. But on 64 bit with mixed mode enabled, this commit adds one compare instruction to each invocation of a boot service and, depending on the code path selected, two jump instructions. (Most of the time gcc arranges the jumps in the 32 bit code path.) The result is a minuscule performance penalty and the binary code becomes slightly larger and more difficult to read when disassembled. This isn't a hot path, so these drawbacks are arguably outweighed by the attainable simplification of the C code. We have some overhead anyway for thunking or conversion between calling conventions. The 8 boot services can consequently be removed from struct efi_config. No functional change intended (for now). Example -- invocation of free_pool before (64 bit code path): 0x2d4 movq %ds:efi_early, %rdx ; efi_early 0x2db movq %ss:arg_0-0x20(%rsp), %rsi 0x2e0 xorl %eax, %eax 0x2e2 movq %ds:0x28(%rdx), %rdi ; efi_early->free_pool 0x2e6 callq *%ds:0x58(%rdx) ; efi_early->call() Example -- invocation of free_pool after (64 / 32 bit mixed code path): 0x0dc movq %ds:efi_early, %rax ; efi_early 0x0e3 cmpb $0, %ds:0x28(%rax) ; !efi_early->is64 ? 0x0e7 movq %ds:0x20(%rax), %rdx ; efi_early->call() 0x0eb movq %ds:0x10(%rax), %rax ; efi_early->boot_services 0x0ef je $0x150 0x0f1 movq %ds:0x48(%rax), %rdi ; free_pool (64 bit) 0x0f5 xorl %eax, %eax 0x0f7 callq *%rdx ... 0x150 movl %ds:0x30(%rax), %edi ; free_pool (32 bit) 0x153 jmp $0x0f5 Size of eboot.o text section: CONFIG_X86_32: 6464 before, 6318 after CONFIG_X86_64 && !CONFIG_EFI_MIXED: 7670 before, 7573 after CONFIG_X86_64 && CONFIG_EFI_MIXED: 7670 before, 8319 after Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-09x86/efi: Remove unused find_bits() functionLukas Wunner1-23/+0
Left behind by commit fc37206427ce ("efi/libstub: Move Graphics Output Protocol handling to generic code"). Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-09x86/efi: Initialize status to ensure garbage is not returned on small sizeColin Ian King1-2/+2
Although very unlikey, if size is too small or zero, then we end up with status not being set and returning garbage. Instead, initializing status to EFI_INVALID_PARAMETER to indicate that size is invalid in the calls to setup_uga32 and setup_uga64. Signed-off-by: Colin Ian King <colin.king@canonical.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05x86/efi: Use efi_exit_boot_services()Jeffrey Hugo1-69/+67
The eboot code directly calls ExitBootServices. This is inadvisable as the UEFI spec details a complex set of errors, race conditions, and API interactions that the caller of ExitBootServices must get correct. The eboot code attempts allocations after calling ExitBootSerives which is not permitted per the spec. Call the efi_exit_boot_services() helper intead, which handles the allocation scenario properly. Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-09-05efi/libstub: Allocate headspace in efi_get_memory_map()Jeffrey Hugo1-7/+13
efi_get_memory_map() allocates a buffer to store the memory map that it retrieves. This buffer may need to be reused by the client after ExitBootServices() is called, at which point allocations are not longer permitted. To support this usecase, provide the allocated buffer size back to the client, and allocate some additional headroom to account for any reasonable growth in the map that is likely to happen between the call to efi_get_memory_map() and the client reusing the buffer. Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Leif Lindholm <leif.lindholm@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
2016-07-26Merge branch 'x86-boot-for-linus' of ↵Linus Torvalds5-182/+190
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Ingo Molnar: "The main changes: - add initial commits to randomize kernel memory section virtual addresses, enabled via a new kernel option: RANDOMIZE_MEMORY (Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu) - enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees Cook) - EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar) - misc cleanups/fixes" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Simplify EBDA-vs-BIOS reservation logic x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does x86/boot: Reorganize and clean up the BIOS area reservation code x86/mm: Do not reference phys addr beyond kernel x86/mm: Add memory hotplug support for KASLR memory randomization x86/mm: Enable KASLR for vmalloc memory regions x86/mm: Enable KASLR for physical mapping memory regions x86/mm: Implement ASLR for kernel memory regions x86/mm: Separate variable for trampoline PGD x86/mm: Add PUD VA support for physical mapping x86/mm: Update physical mapping variable names x86/mm: Refactor KASLR entropy functions x86/KASLR: Fix boot crash with certain memory configurations x86/boot/64: Add forgotten end of function marker x86/KASLR: Allow randomization below the load address x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G x86/KASLR: Randomize virtual address separately x86/KASLR: Clarify identity map interface x86/boot: Refuse to build with data relocations x86/KASLR, x86/power: Remove x86 hibernation restrictions
2016-07-08x86/mm: Enable KASLR for physical mapping memory regionsThomas Garnier1-0/+3
Add the physical mapping in the list of randomized memory regions. The physical memory mapping holds most allocations from boot and heap allocators. Knowing the base address and physical memory size, an attacker can deduce the PDE virtual address for the vDSO memory page. This attack was demonstrated at CanSecWest 2016, in the following presentation: "Getting Physical: Extreme Abuse of Intel Based Paged Systems": https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/blob/master/Presentation/CanSec2016_Presentation.pdf (See second part of the presentation). The exploits used against Linux worked successfully against 4.6+ but fail with KASLR memory enabled: https://github.com/n3k/CansecWest2016_Getting_Physical_Extreme_Abuse_of_Intel_Based_Paging_Systems/tree/master/Demos/Linux/exploits Similar research was done at Google leading to this patch proposal. Variants exists to overwrite /proc or /sys objects ACLs leading to elevation of privileges. These variants were tested against 4.6+. The page offset used by the compressed kernel retains the static value since it is not yet randomized during this boot stage. Signed-off-by: Thomas Garnier <thgarnie@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Alexander Kuleshov <kuleshovmail@gmail.com> Cc: Alexander Popov <alpopov@ptsecurity.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1466556426-32664-7-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-08x86/mm: Refactor KASLR entropy functionsThomas Garnier1-71/+5
Move the KASLR entropy functions into arch/x86/lib to be used in early kernel boot for KASLR memory randomization. Signed-off-by: Thomas Garnier <thgarnie@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Alexander Kuleshov <kuleshovmail@gmail.com> Cc: Alexander Popov <alpopov@ptsecurity.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Joerg Roedel <jroedel@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1466556426-32664-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-08x86/KASLR: Fix boot crash with certain memory configurationsBaoquan He1-0/+2
Ye Xiaolong reported this boot crash: | | XZ-compressed data is corrupt | | -- System halted | Fix the bug in mem_avoid_overlap() of finding the earliest overlap. Reported-and-tested-by: Ye Xiaolong <xiaolong.ye@intel.com> Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-27x86/efi: Remove unused variable 'efi'Colin Ian King1-2/+0
Remove unused variable 'efi', it is never used. This fixes the following clang build warning: arch/x86/boot/compressed/eboot.c:803:2: warning: Value stored to 'efi' is never read Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1466839230-12781-4-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/KASLR: Allow randomization below the load addressYinghai Lu1-2/+9
Currently the kernel image physical address randomization's lower boundary is the original kernel load address. For bootloaders that load kernels into very high memory (e.g. kexec), this means randomization takes place in a very small window at the top of memory, ignoring the large region of physical memory below the load address. Since mem_avoid[] is already correctly tracking the regions that must be avoided, this patch changes the minimum address to whatever is less: 512M (to conservatively avoid unknown things in lower memory) or the load address. Now, for example, if the kernel is loaded at 8G, [512M, 8G) will be added to the list of possible physical memory positions. Signed-off-by: Yinghai Lu <yinghai@kernel.org> [ Rewrote the changelog, refactored the code to use min(). ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1464216334-17200-6-git-send-email-keescook@chromium.org [ Edited the changelog some more, plus the code comment as well. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/KASLR: Extend kernel image physical address randomization to addresses ↵Kees Cook1-46/+69
larger than 4G We want the physical address to be randomized anywhere between 16MB and the top of physical memory (up to 64TB). This patch exchanges the prior slots[] array for the new slot_areas[] array, and lifts the limitation of KERNEL_IMAGE_SIZE on the physical address offset for 64-bit. As before, process_e820_entry() walks memory and populates slot_areas[], splitting on any detected mem_avoid collisions. Finally, since the slots[] array and its associated functions are not needed any more, so they are removed. Based on earlier patches by Baoquan He. Originally-from: Baoquan He <bhe@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1464216334-17200-5-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/KASLR: Randomize virtual address separatelyBaoquan He3-48/+64
The current KASLR implementation randomizes the physical and virtual addresses of the kernel together (both are offset by the same amount). It calculates the delta of the physical address where vmlinux was linked to load and where it is finally loaded. If the delta is not equal to 0 (i.e. the kernel was relocated), relocation handling needs be done. On 64-bit, this patch randomizes both the physical address where kernel is decompressed and the virtual address where kernel text is mapped and will execute from. We now have two values being chosen, so the function arguments are reorganized to pass by pointer so they can be directly updated. Since relocation handling only depends on the virtual address, we must check the virtual delta, not the physical delta for processing kernel relocations. This also populates the page table for the new virtual address range. 32-bit does not support a separate virtual address, so it continues to use the physical offset for its virtual offset. Additionally updates the sanity checks done on the resulting kernel addresses since they are potentially separate now. [kees: rewrote changelog, limited virtual split to 64-bit only, update checks] [kees: fix CONFIG_RANDOMIZE_BASE=n boot failure] Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1464216334-17200-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/KASLR: Clarify identity map interfaceKees Cook3-10/+22
This extracts the call to prepare_level4() into a top-level function that the user of the pagetable.c interface must call to initialize the new page tables. For clarity and to match the "finalize" function, it has been renamed to initialize_identity_maps(). This function also gains the initialization of mapping_info so we don't have to do it each time in add_identity_map(). Additionally add copyright notice to the top, to make it clear that the bulk of the pagetable.c code was written by Yinghai, and that I just added bugs later. :) Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1464216334-17200-3-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/boot: Refuse to build with data relocationsKees Cook1-0/+18
The compressed kernel is built with -fPIC/-fPIE so that it can run in any location a bootloader happens to put it. However, since ELF relocation processing is not happening (and all the relocation information has already been stripped at link time), none of the code can use data relocations (e.g. static assignments of pointers). This is already noted in a warning comment at the top of misc.c, but this adds an explicit check for the condition during the linking stage to block any such bugs from appearing. If this was in place with the earlier bug in pagetable.c, the build would fail like this: ... CC arch/x86/boot/compressed/pagetable.o DATAREL arch/x86/boot/compressed/vmlinux error: arch/x86/boot/compressed/pagetable.o has data relocations! make[2]: *** [arch/x86/boot/compressed/vmlinux] Error 1 ... A clean build shows: ... CC arch/x86/boot/compressed/pagetable.o DATAREL arch/x86/boot/compressed/vmlinux LD arch/x86/boot/compressed/vmlinux ... Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1464216334-17200-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-26x86/KASLR, x86/power: Remove x86 hibernation restrictionsKees Cook1-7/+0
With the following fix: 70595b479ce1 ("x86/power/64: Fix crash whan the hibernation code passes control to the image kernel") ... there is no longer a problem with hibernation resuming a KASLR-booted kernel image, so remove the restriction. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Len Brown <len.brown@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux PM list <linux-pm@vger.kernel.org> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20160613221002.GA29719@www.outflux.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-27Merge branch 'kbuild' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: - new option CONFIG_TRIM_UNUSED_KSYMS which does a two-pass build and unexports symbols which are not used in the current config [Nicolas Pitre] - several kbuild rule cleanups [Masahiro Yamada] - warning option adjustments for gcov etc [Arnd Bergmann] - a few more small fixes * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (31 commits) kbuild: move -Wunused-const-variable to W=1 warning level kbuild: fix if_change and friends to consider argument order kbuild: fix adjust_autoksyms.sh for modules that need only one symbol kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same line gcov: disable -Wmaybe-uninitialized warning gcov: disable tree-loop-im to reduce stack usage gcov: disable for COMPILE_TEST Kbuild: disable 'maybe-uninitialized' warning for CONFIG_PROFILE_ALL_BRANCHES Kbuild: change CC_OPTIMIZE_FOR_SIZE definition kbuild: forbid kernel directory to contain spaces and colons kbuild: adjust ksym_dep_filter for some cmd_* renames kbuild: Fix dependencies for final vmlinux link kbuild: better abstract vmlinux sequential prerequisites kbuild: fix call to adjust_autoksyms.sh when output directory specified kbuild: Get rid of KBUILD_STR kbuild: rename cmd_as_s_S to cmd_cpp_s_S kbuild: rename cmd_cc_i_c to cmd_cpp_i_c kbuild: drop redundant "PHONY += FORCE" kbuild: delete unnecessary "@:" kbuild: mark help target as PHONY ...
2016-05-17Merge branch 'x86-boot-for-linus' of ↵Linus Torvalds14-527/+835
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Ingo Molnar: "The biggest changes in this cycle were: - prepare for more KASLR related changes, by restructuring, cleaning up and fixing the existing boot code. (Kees Cook, Baoquan He, Yinghai Lu) - simplifly/concentrate subarch handling code, eliminate paravirt_enabled() usage. (Luis R Rodriguez)" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits) x86/KASLR: Clarify purpose of each get_random_long() x86/KASLR: Add virtual address choosing function x86/KASLR: Return earliest overlap when avoiding regions x86/KASLR: Add 'struct slot_area' to manage random_addr slots x86/boot: Add missing file header comments x86/KASLR: Initialize mapping_info every time x86/boot: Comment what finalize_identity_maps() does x86/KASLR: Build identity mappings on demand x86/boot: Split out kernel_ident_mapping_init() x86/boot: Clean up indenting for asm/boot.h x86/KASLR: Improve comments around the mem_avoid[] logic x86/boot: Simplify pointer casting in choose_random_location() x86/KASLR: Consolidate mem_avoid[] entries x86/boot: Clean up pointer casting x86/boot: Warn on future overlapping memcpy() use x86/boot: Extract error reporting functions x86/boot: Correctly bounds-check relocations x86/KASLR: Clean up unused code from old 'run_size' and rename it to 'kernel_total_size' x86/boot: Fix "run_size" calculation x86/boot: Calculate decompression size during boot not build ...
2016-05-10x86/KASLR: Clarify purpose of each get_random_long()Kees Cook1-4/+5
KASLR will be calling get_random_long() twice, but the debug output won't distinguishing between them. This patch adds a report on when it is fetching the physical vs virtual address. With this, once the virtual offset is separate, the report changes from: KASLR using RDTSC... KASLR using RDTSC... into: Physical KASLR using RDTSC... Virtual KASLR using RDTSC... Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-7-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/KASLR: Add virtual address choosing functionBaoquan He1-4/+28
To support randomizing the kernel virtual address separately from the physical address, this patch adds find_random_virt_addr() to choose a slot anywhere between LOAD_PHYSICAL_ADDR and KERNEL_IMAGE_SIZE. Since this address is virtual, not physical, we can place the kernel anywhere in this region, as long as it is aligned and (in the case of kernel being larger than the slot size) placed with enough room to load the entire kernel image. For clarity and readability, find_random_addr() is renamed to find_random_phys_addr() and has "size" renamed to "image_size" to match find_random_virt_addr(). Signed-off-by: Baoquan He <bhe@redhat.com> [ Rewrote changelog, refactored slot calculation for readability. ] [ Renamed find_random_phys_addr() and size argument. ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-6-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/KASLR: Return earliest overlap when avoiding regionsKees Cook1-9/+20
In preparation for being able to detect where to split up contiguous memory regions that overlap with memory regions to avoid, we need to pass back what the earliest overlapping region was. This modifies the overlap checker to return that information. Based on a separate mem_min_overlap() implementation by Baoquan He. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-5-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/KASLR: Add 'struct slot_area' to manage random_addr slotsBaoquan He1-0/+29
In order to support KASLR moving the kernel anywhere in physical memory (which could be up to 64TB), we need to handle counting the potential randomization locations in a more efficient manner. In the worst case with 64TB, there could be roughly 32 * 1024 * 1024 randomization slots if CONFIG_PHYSICAL_ALIGN is 0x1000000. Currently the starting address of candidate positions is stored into the slots[] array, one at a time. This method would cost too much memory and it's also very inefficient to get and save the slot information into the slot array one by one. This patch introduces 'struct slot_area' to manage each contiguous region of randomization slots. Each slot_area will contain the starting address and how many available slots are in this area. As with the original code, the slot_areas[] will avoid the mem_avoid[] regions. Since setup_data is a linked list, it could contain an unknown number of memory regions to be avoided, which could cause us to fragment the contiguous memory that the slot_area array is tracking. In normal operation this level of fragmentation will be extremely rare, but we choose a suitably large value (100) for the array. If setup_data forces the slot_area array to become highly fragmented and there are more slots available beyond the first 100 found, the rest will be ignored for KASLR selection. The function store_slot_info() is used to calculate the number of slots available in the passed-in memory region and stores it into slot_areas[] after adjusting for alignment and size requirements. Signed-off-by: Baoquan He <bhe@redhat.com> [ Rewrote changelog, squashed with new functions. ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/boot: Add missing file header commentsKees Cook1-1/+1
There were some files with missing header comments. Since they are included from both compressed and regular kernels, make note of that. Also corrects a typo in the mem_avoid comments. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-3-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/KASLR: Initialize mapping_info every timeKees Cook1-11/+5
As it turns out, mapping_info DOES need to be initialized every time, because pgt_data address could be changed during kernel relocation. So it can not be build time assigned. Without this, page tables were not being corrected updated, which could cause reboots when a physical address beyond 2G was chosen. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462825332-10505-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10x86/boot: Comment what finalize_identity_maps() doesBorislav Petkov1-0/+2
So it is not really obvious that finalize_identity_maps() doesn't do any finalization but it *actually* writes CR3 with the ident PGD. Comment that at the call site. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: bhe@redhat.com Cc: dyoung@redhat.com Cc: jkosina@suse.cz Cc: linux-tip-commits@vger.kernel.org Cc: luto@kernel.org Cc: vgoyal@redhat.com Cc: yinghai@kernel.org Link: http://lkml.kernel.org/r/20160507100541.GA24613@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07x86/KASLR: Build identity mappings on demandKees Cook5-2/+168
Currently KASLR only supports relocation in a small physical range (from 16M to 1G), due to using the initial kernel page table identity mapping. To support ranges above this, we need to have an identity mapping for the desired memory range before we can decompress (and later run) the kernel. 32-bit kernels already have the needed identity mapping. This patch adds identity mappings for the needed memory ranges on 64-bit kernels. This happens in two possible boot paths: If loaded via startup_32(), we need to set up the needed identity map. If loaded from a 64-bit bootloader, the bootloader will have already set up an identity mapping, and we'll start via the compressed kernel's startup_64(). In this case, the bootloader's page tables need to be avoided while selecting the new uncompressed kernel location. If not, the decompressor could overwrite them during decompression. To accomplish this, we could walk the pagetable and find every page that is used, and add them to mem_avoid, but this needs extra code and will require increasing the size of the mem_avoid array. Instead, we can create a new set of page tables for our own identity mapping instead. The pages for the new page table will come from the _pagetable section of the compressed kernel, which means they are already contained by in mem_avoid array. To do this, we reuse the code from the uncompressed kernel's identity mapping routines. The _pgtable will be shared by both the 32-bit and 64-bit paths to reduce init_size, as now the compressed kernel's _rodata to _end will contribute to init_size. To handle the possible mappings, we need to increase the existing page table buffer size: When booting via startup_64(), we need to cover the old VO, params, cmdline and uncompressed kernel. In an extreme case we could have them all beyond the 512G boundary, which needs (2+2)*4 pages with 2M mappings. And we'll need 2 for first 2M for VGA RAM. One more is needed for level4. This gets us to 19 pages total. When booting via startup_32(), KASLR could move the uncompressed kernel above 4G, so we need to create extra identity mappings, which should only need (2+2) pages at most when it is beyond the 512G boundary. So 19 pages is sufficient for this case as well. The resulting BOOT_*PGT_SIZE defines use the "_SIZE" suffix on their names to maintain logical consistency with the existing BOOT_HEAP_SIZE and BOOT_STACK_SIZE defines. This patch is based on earlier patches from Yinghai Lu and Baoquan He. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462572095-11754-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07x86/KASLR: Improve comments around the mem_avoid[] logicKees Cook1-48/+78
This attempts to improve the comments that describe how the memory range used for decompression is avoided. Additionally uses an enum instead of raw numbers for the mem_avoid[] indexing. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/20160506194459.GA16480@www.outflux.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-07x86/boot: Simplify pointer casting in choose_random_location()Borislav Petkov3-17/+13
Pass them down as 'unsigned long' directly and get rid of more casting and assignments. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: bhe@redhat.com Cc: dyoung@redhat.com Cc: linux-tip-commits@vger.kernel.org Cc: luto@kernel.org Cc: vgoyal@redhat.com Cc: yinghai@kernel.org Link: http://lkml.kernel.org/r/20160506115015.GI24044@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-06x86/KASLR: Consolidate mem_avoid[] entriesYinghai Lu1-16/+61
The mem_avoid[] array is used to track positions that should be avoided (like the compressed kernel, decompression code, etc) when selecting a memory position for the randomly relocated kernel. Since ZO is now at the end of the decompression buffer and the decompression code (and its heap and stack) are at the front, we can safely consolidate the decompression entry, the heap entry, and the stack entry. The boot_params memory, however, could be elsewhere, so it should be explicitly included. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Baoquan He <bhe@redhat.com> [ Rwrote changelog, cleaned up code comments. ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462486436-3707-3-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-06x86/boot: Clean up pointer castingKees Cook2-11/+19
Currently extract_kernel() defines the input and output buffer pointers as "unsigned char *" since that's effectively what they are. It passes these to the decompressor routine and to the ELF parser, which both logically deal with buffer pointers too. There is some casting ("unsigned long") done to validate the numerical value of the pointers, but it is relatively limited. However, choose_random_location() operates almost exclusively on the numerical representation of these pointers, so it ended up carrying a lot of "unsigned long" casts. With the future physical/virtual split these casts were going to multiply, so this attempts to solve the problem by doing all the casting in choose_random_location()'s entry and return instead of through-out the code. Adjusts argument names to be more meaningful, and changes one us of "choice" to "output" to make the future physical/virtual split more clear (i.e. "choice" should be strictly a function return value and not used as an intermediate). Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462486436-3707-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-03x86/boot: Warn on future overlapping memcpy() useKees Cook1-3/+13
If an overlapping memcpy() is ever attempted, we should at least report it, in case it might lead to problems, so it could be changed to a memmove() call instead. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Lasse Collin <lasse.collin@tukaani.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1462229461-3370-3-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-03x86/boot: Extract error reporting functionsKees Cook7-19/+34
Currently to use warn(), a caller would need to include misc.h. However, this means they would get the (unavailable during compressed boot) gcc built-in memcpy family of functions. But since string.c is defining these memcpy functions for use by misc.c, we end up in a weird circular dependency. To break this loop, move the error reporting functions outside of misc.c with their own header so that they can be independently included by other sources. Since the screen-writing routines use memmove(), keep the low-level *_putstr() functions in misc.c. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Lasse Collin <lasse.collin@tukaani.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1462229461-3370-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-29x86/boot: Correctly bounds-check relocationsYinghai Lu2-2/+2
Relocation handling performs bounds checking on the resulting calculated addresses. The existing code uses output_len (VO size plus relocs size) as the max address. This is not right since the max_addr check should stop at the end of VO and exclude bss, brk, etc, which follows. The valid range should be VO [_text, __bss_start] in the loaded physical address space. This patch adds an export for __bss_start in voffset.h and uses it to set the correct limit for max_addr. Signed-off-by: Yinghai Lu <yinghai@kernel.org> [ Rewrote the changelog. ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1461888548-32439-7-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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