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2024-05-14arch: make execmem setup available regardless of CONFIG_MODULESMike Rapoport (IBM)
execmem does not depend on modules, on the contrary modules use execmem. To make execmem available when CONFIG_MODULES=n, for instance for kprobes, split execmem_params initialization out from arch/*/kernel/module.c and compile it when CONFIG_EXECMEM=y Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2024-05-14mm/execmem, arch: convert remaining overrides of module_alloc to execmemMike Rapoport (IBM)
Extend execmem parameters to accommodate more complex overrides of module_alloc() by architectures. This includes specification of a fallback range required by arm, arm64 and powerpc, EXECMEM_MODULE_DATA type required by powerpc, support for allocation of KASAN shadow required by s390 and x86 and support for late initialization of execmem required by arm64. The core implementation of execmem_alloc() takes care of suppressing warnings when the initial allocation fails but there is a fallback range defined. Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Song Liu <song@kernel.org> Tested-by: Liviu Dudau <liviu@dudau.co.uk> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-12-10x86/paravirt: Switch mixed paravirt/alternative calls to alternativesJuergen Gross
Instead of stacking alternative and paravirt patching, use the new ALT_FLAG_CALL flag to switch those mixed calls to pure alternative handling. Eliminate the need to be careful regarding the sequence of alternative and paravirt patching. [ bp: Touch up commit message. ] Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20231210062138.2417-5-jgross@suse.com
2023-07-10x86/alternative: Rename apply_ibt_endbr()Peter Zijlstra
The current name doesn't reflect what it does very well. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lkml.kernel.org/r/20230622144321.427441595%40infradead.org
2023-03-09module: replace module_layout with module_memorySong Liu
module_layout manages different types of memory (text, data, rodata, etc.) in one allocation, which is problematic for some reasons: 1. It is hard to enable CONFIG_STRICT_MODULE_RWX. 2. It is hard to use huge pages in modules (and not break strict rwx). 3. Many archs uses module_layout for arch-specific data, but it is not obvious how these data are used (are they RO, RX, or RW?) Improve the scenario by replacing 2 (or 3) module_layout per module with up to 7 module_memory per module: MOD_TEXT, MOD_DATA, MOD_RODATA, MOD_RO_AFTER_INIT, MOD_INIT_TEXT, MOD_INIT_DATA, MOD_INIT_RODATA, and allocating them separately. This adds slightly more entries to mod_tree (from up to 3 entries per module, to up to 7 entries per module). However, this at most adds a small constant overhead to __module_address(), which is expected to be fast. Various archs use module_layout for different data. These data are put into different module_memory based on their location in module_layout. IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT; data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc. module_memory simplifies quite some of the module code. For example, ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a different allocator for the data. kernel/module/strict_rwx.c is also much cleaner with module_memory. Signed-off-by: Song Liu <song@kernel.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-02-23Merge tag 'livepatching-for-6.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching Pull livepatching updates from Petr Mladek: - Allow reloading a livepatched module by clearing livepatch-specific relocations in the livepatch module. Otherwise, the repeated load would fail on consistency checks. * tag 'livepatching-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: livepatch,x86: Clear relocation targets on a module removal x86/module: remove unused code in __apply_relocate_add
2023-02-03livepatch,x86: Clear relocation targets on a module removalSong Liu
Josh reported a bug: When the object to be patched is a module, and that module is rmmod'ed and reloaded, it fails to load with: module: x86/modules: Skipping invalid relocation target, existing value is nonzero for type 2, loc 00000000ba0302e9, val ffffffffa03e293c livepatch: failed to initialize patch 'livepatch_nfsd' for module 'nfsd' (-8) livepatch: patch 'livepatch_nfsd' failed for module 'nfsd', refusing to load module 'nfsd' The livepatch module has a relocation which references a symbol in the _previous_ loading of nfsd. When apply_relocate_add() tries to replace the old relocation with a new one, it sees that the previous one is nonzero and it errors out. He also proposed three different solutions. We could remove the error check in apply_relocate_add() introduced by commit eda9cec4c9a1 ("x86/module: Detect and skip invalid relocations"). However the check is useful for detecting corrupted modules. We could also deny the patched modules to be removed. If it proved to be a major drawback for users, we could still implement a different approach. The solution would also complicate the existing code a lot. We thus decided to reverse the relocation patching (clear all relocation targets on x86_64). The solution is not universal and is too much arch-specific, but it may prove to be simpler in the end. Reported-by: Josh Poimboeuf <jpoimboe@redhat.com> Originally-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Song Liu <song@kernel.org> Acked-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230125185401.279042-2-song@kernel.org
2023-02-03x86/module: remove unused code in __apply_relocate_addSong Liu
This "#if 0" block has been untouched for many years. Remove it to clean up the code. Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Song Liu <song@kernel.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230125185401.279042-1-song@kernel.org
2022-12-14Merge tag 'x86_core_for_v6.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 core updates from Borislav Petkov: - Add the call depth tracking mitigation for Retbleed which has been long in the making. It is a lighterweight software-only fix for Skylake-based cores where enabling IBRS is a big hammer and causes a significant performance impact. What it basically does is, it aligns all kernel functions to 16 bytes boundary and adds a 16-byte padding before the function, objtool collects all functions' locations and when the mitigation gets applied, it patches a call accounting thunk which is used to track the call depth of the stack at any time. When that call depth reaches a magical, microarchitecture-specific value for the Return Stack Buffer, the code stuffs that RSB and avoids its underflow which could otherwise lead to the Intel variant of Retbleed. This software-only solution brings a lot of the lost performance back, as benchmarks suggest: https://lore.kernel.org/all/20220915111039.092790446@infradead.org/ That page above also contains a lot more detailed explanation of the whole mechanism - Implement a new control flow integrity scheme called FineIBT which is based on the software kCFI implementation and uses hardware IBT support where present to annotate and track indirect branches using a hash to validate them - Other misc fixes and cleanups * tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (80 commits) x86/paravirt: Use common macro for creating simple asm paravirt functions x86/paravirt: Remove clobber bitmask from .parainstructions x86/debug: Include percpu.h in debugreg.h to get DECLARE_PER_CPU() et al x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit x86/Kconfig: Enable kernel IBT by default x86,pm: Force out-of-line memcpy() objtool: Fix weak hole vs prefix symbol objtool: Optimize elf_dirty_reloc_sym() x86/cfi: Add boot time hash randomization x86/cfi: Boot time selection of CFI scheme x86/ibt: Implement FineIBT objtool: Add --cfi to generate the .cfi_sites section x86: Add prefix symbols for function padding objtool: Add option to generate prefix symbols objtool: Avoid O(bloody terrible) behaviour -- an ode to libelf objtool: Slice up elf_create_section_symbol() kallsyms: Revert "Take callthunks into account" x86: Unconfuse CONFIG_ and X86_FEATURE_ namespaces x86/retpoline: Fix crash printing warning x86/paravirt: Fix a !PARAVIRT build warning ...
2022-12-12Merge tag 'random-6.2-rc1-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/crng/random Pull random number generator updates from Jason Donenfeld: - Replace prandom_u32_max() and various open-coded variants of it, there is now a new family of functions that uses fast rejection sampling to choose properly uniformly random numbers within an interval: get_random_u32_below(ceil) - [0, ceil) get_random_u32_above(floor) - (floor, U32_MAX] get_random_u32_inclusive(floor, ceil) - [floor, ceil] Coccinelle was used to convert all current users of prandom_u32_max(), as well as many open-coded patterns, resulting in improvements throughout the tree. I'll have a "late" 6.1-rc1 pull for you that removes the now unused prandom_u32_max() function, just in case any other trees add a new use case of it that needs to converted. According to linux-next, there may be two trivial cases of prandom_u32_max() reintroductions that are fixable with a 's/.../.../'. So I'll have for you a final conversion patch doing that alongside the removal patch during the second week. This is a treewide change that touches many files throughout. - More consistent use of get_random_canary(). - Updates to comments, documentation, tests, headers, and simplification in configuration. - The arch_get_random*_early() abstraction was only used by arm64 and wasn't entirely useful, so this has been replaced by code that works in all relevant contexts. - The kernel will use and manage random seeds in non-volatile EFI variables, refreshing a variable with a fresh seed when the RNG is initialized. The RNG GUID namespace is then hidden from efivarfs to prevent accidental leakage. These changes are split into random.c infrastructure code used in the EFI subsystem, in this pull request, and related support inside of EFISTUB, in Ard's EFI tree. These are co-dependent for full functionality, but the order of merging doesn't matter. - Part of the infrastructure added for the EFI support is also used for an improvement to the way vsprintf initializes its siphash key, replacing an sleep loop wart. - The hardware RNG framework now always calls its correct random.c input function, add_hwgenerator_randomness(), rather than sometimes going through helpers better suited for other cases. - The add_latent_entropy() function has long been called from the fork handler, but is a no-op when the latent entropy gcc plugin isn't used, which is fine for the purposes of latent entropy. But it was missing out on the cycle counter that was also being mixed in beside the latent entropy variable. So now, if the latent entropy gcc plugin isn't enabled, add_latent_entropy() will expand to a call to add_device_randomness(NULL, 0), which adds a cycle counter, without the absent latent entropy variable. - The RNG is now reseeded from a delayed worker, rather than on demand when used. Always running from a worker allows it to make use of the CPU RNG on platforms like S390x, whose instructions are too slow to do so from interrupts. It also has the effect of adding in new inputs more frequently with more regularity, amounting to a long term transcript of random values. Plus, it helps a bit with the upcoming vDSO implementation (which isn't yet ready for 6.2). - The jitter entropy algorithm now tries to execute on many different CPUs, round-robining, in hopes of hitting even more memory latencies and other unpredictable effects. It also will mix in a cycle counter when the entropy timer fires, in addition to being mixed in from the main loop, to account more explicitly for fluctuations in that timer firing. And the state it touches is now kept within the same cache line, so that it's assured that the different execution contexts will cause latencies. * tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits) random: include <linux/once.h> in the right header random: align entropy_timer_state to cache line random: mix in cycle counter when jitter timer fires random: spread out jitter callback to different CPUs random: remove extraneous period and add a missing one in comments efi: random: refresh non-volatile random seed when RNG is initialized vsprintf: initialize siphash key using notifier random: add back async readiness notifier random: reseed in delayed work rather than on-demand random: always mix cycle counter in add_latent_entropy() hw_random: use add_hwgenerator_randomness() for early entropy random: modernize documentation comment on get_random_bytes() random: adjust comment to account for removed function random: remove early archrandom abstraction random: use random.trust_{bootloader,cpu} command line option only stackprotector: actually use get_random_canary() stackprotector: move get_random_canary() into stackprotector.h treewide: use get_random_u32_inclusive() when possible treewide: use get_random_u32_{above,below}() instead of manual loop treewide: use get_random_u32_below() instead of deprecated function ...
2022-11-22x86/alternative: Consistently patch SMP locks in vmlinux and modulesJulian Pidancet
alternatives_smp_module_add() restricts patching of SMP lock prefixes to the text address range passed as an argument. For vmlinux, patching all the instructions located between the _text and _etext symbols is allowed. That includes the .text section but also other sections such as .text.hot and .text.unlikely. As per the comment inside the 'struct smp_alt_module' definition, the original purpose of this restriction is to avoid patching the init code because in the case when one boots with a single CPU, the LOCK prefixes to the locking primitives are removed. Later on, when other CPUs are onlined, those LOCK prefixes get added back in but by that time the .init code is very likely removed so patching that would be a bad idea. For modules, the current code only allows patching instructions located inside the .text segment, excluding other sections such as .text.hot or .text.unlikely, which may need patching. Make patching of the kernel core and modules more consistent by allowing all text sections of modules except .init.text to be patched in module_finalize(). For that, use mod->core_layout.base/mod->core_layout.text_size as the address range allowed to be patched, which include all the code sections except the init code. [ bp: Massage and expand commit message. ] Signed-off-by: Julian Pidancet <julian.pidancet@oracle.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20221027204906.511277-1-julian.pidancet@oracle.com
2022-11-18treewide: use get_random_u32_inclusive() when possibleJason A. Donenfeld
These cases were done with this Coccinelle: @@ expression H; expression L; @@ - (get_random_u32_below(H) + L) + get_random_u32_inclusive(L, H + L - 1) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - + E - - E ) @@ expression H; expression L; expression E; @@ get_random_u32_inclusive(L, H - - E - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - - E + F - + E ) @@ expression H; expression L; expression E; expression F; @@ get_random_u32_inclusive(L, H - + E + F - - E ) And then subsequently cleaned up by hand, with several automatic cases rejected if it didn't make sense contextually. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-18treewide: use get_random_u32_below() instead of deprecated functionJason A. Donenfeld
This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs Reviewed-by: SeongJae Park <sj@kernel.org> # for damon Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-01x86/ibt: Implement FineIBTPeter Zijlstra
Implement an alternative CFI scheme that merges both the fine-grained nature of kCFI but also takes full advantage of the coarse grained hardware CFI as provided by IBT. To contrast: kCFI is a pure software CFI scheme and relies on being able to read text -- specifically the instruction *before* the target symbol, and does the hash validation *before* doing the call (otherwise control flow is compromised already). FineIBT is a software and hardware hybrid scheme; by ensuring every branch target starts with a hash validation it is possible to place the hash validation after the branch. This has several advantages: o the (hash) load is avoided; no memop; no RX requirement. o IBT WAIT-FOR-ENDBR state is a speculation stop; by placing the hash validation in the immediate instruction after the branch target there is a minimal speculation window and the whole is a viable defence against SpectreBHB. o Kees feels obliged to mention it is slightly more vulnerable when the attacker can write code. Obviously this patch relies on kCFI, but additionally it also relies on the padding from the call-depth-tracking patches. It uses this padding to place the hash-validation while the call-sites are re-written to modify the indirect target to be 16 bytes in front of the original target, thus hitting this new preamble. Notably, there is no hardware that needs call-depth-tracking (Skylake) and supports IBT (Tigerlake and onwards). Suggested-by: Joao Moreira (Intel) <joao@overdrivepizza.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20221027092842.634714496@infradead.org
2022-10-17x86/modules: Add call patchingThomas Gleixner
As for the builtins create call thunks and patch the call sites to call the thunk on Intel SKL CPUs for retbleed mitigation. Note, that module init functions are ignored for sake of simplicity because loading modules is not something which is done in high frequent loops and the attacker has not really a handle on when this happens in order to launch a matching attack. The depth tracking will still work for calls into the builtins and because the call is not accounted it will underflow faster and overstuff, but that's mitigated by the saturating counter and the side effect is only temporary. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220915111147.575673066@infradead.org
2022-10-17x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc()Thomas Gleixner
Instead of resetting permissions all over the place when freeing module memory tell the vmalloc code to do so. Avoids the exercise for the next upcoming user. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220915111143.406703869@infradead.org
2022-10-11treewide: use prandom_u32_max() when possible, part 1Jason A. Donenfeld
Rather than incurring a division or requesting too many random bytes for the given range, use the prandom_u32_max() function, which only takes the minimum required bytes from the RNG and avoids divisions. This was done mechanically with this coccinelle script: @basic@ expression E; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u64; @@ ( - ((T)get_random_u32() % (E)) + prandom_u32_max(E) | - ((T)get_random_u32() & ((E) - 1)) + prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2) | - ((u64)(E) * get_random_u32() >> 32) + prandom_u32_max(E) | - ((T)get_random_u32() & ~PAGE_MASK) + prandom_u32_max(PAGE_SIZE) ) @multi_line@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; identifier RAND; expression E; @@ - RAND = get_random_u32(); ... when != RAND - RAND %= (E); + RAND = prandom_u32_max(E); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Add one to the literal. @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1: print("Skipping 0x%x for cleanup elsewhere" % (value)) cocci.include_match(False) elif value & (value + 1) != 0: print("Skipping 0x%x because it's not a power of two minus one" % (value)) cocci.include_match(False) elif literal.startswith('0x'): coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1)) else: coccinelle.RESULT = cocci.make_expr("%d" % (value + 1)) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; expression add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + prandom_u32_max(RESULT) @collapse_ret@ type T; identifier VAR; expression E; @@ { - T VAR; - VAR = (E); - return VAR; + return E; } @drop_var@ type T; identifier VAR; @@ { - T VAR; ... when != VAR } Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Yury Norov <yury.norov@gmail.com> Reviewed-by: KP Singh <kpsingh@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390 Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-08-01Merge tag 'locking-core-2022-08-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "This was a fairly quiet cycle for the locking subsystem: - lockdep: Fix a handful of the more complex lockdep_init_map_*() primitives that can lose the lock_type & cause false reports. No such mishap was observed in the wild. - jump_label improvements: simplify the cross-arch support of initial NOP patching by making it arch-specific code (used on MIPS only), and remove the s390 initial NOP patching that was superfluous" * tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Fix lockdep_init_map_*() confusion jump_label: make initial NOP patching the special case jump_label: mips: move module NOP patching into arch code jump_label: s390: avoid pointless initial NOP patching
2022-06-27x86: Undo return-thunk damagePeter Zijlstra
Introduce X86_FEATURE_RETHUNK for those afflicted with needing this. [ bp: Do only INT3 padding - simpler. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-06-24jump_label: mips: move module NOP patching into arch codeArd Biesheuvel
MIPS is the only remaining architecture that needs to patch jump label NOP encodings to initialize them at load time. So let's move the module patching part of that from generic code into arch/mips, and drop it from the others. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220615154142.1574619-3-ardb@kernel.org
2022-03-27Merge tag 'x86_core_for_5.18_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 CET-IBT (Control-Flow-Integrity) support from Peter Zijlstra: "Add support for Intel CET-IBT, available since Tigerlake (11th gen), which is a coarse grained, hardware based, forward edge Control-Flow-Integrity mechanism where any indirect CALL/JMP must target an ENDBR instruction or suffer #CP. Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation is limited to 2 instructions (and typically fewer) on branch targets not starting with ENDBR. CET-IBT also limits speculation of the next sequential instruction after the indirect CALL/JMP [1]. CET-IBT is fundamentally incompatible with retpolines, but provides, as described above, speculation limits itself" [1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html * tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits) kvm/emulate: Fix SETcc emulation for ENDBR x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0 x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0 kbuild: Fixup the IBT kbuild changes x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy x86: Remove toolchain check for X32 ABI capability x86/alternative: Use .ibt_endbr_seal to seal indirect calls objtool: Find unused ENDBR instructions objtool: Validate IBT assumptions objtool: Add IBT/ENDBR decoding objtool: Read the NOENDBR annotation x86: Annotate idtentry_df() x86,objtool: Move the ASM_REACHABLE annotation to objtool.h x86: Annotate call_on_stack() objtool: Rework ASM_REACHABLE x86: Mark __invalid_creds() __noreturn exit: Mark do_group_exit() __noreturn x86: Mark stop_this_cpu() __noreturn objtool: Ignore extra-symbol code objtool: Rename --duplicate to --lto ...
2022-03-24kasan, x86, arm64, s390: rename functions for modules shadowAndrey Konovalov
Rename kasan_free_shadow to kasan_free_module_shadow and kasan_module_alloc to kasan_alloc_module_shadow. These functions are used to allocate/free shadow memory for kernel modules when KASAN_VMALLOC is not enabled. The new names better reflect their purpose. Also reword the comment next to their declaration to improve clarity. Link: https://lkml.kernel.org/r/36db32bde765d5d0b856f77d2d806e838513fe84.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-15x86/alternative: Use .ibt_endbr_seal to seal indirect callsPeter Zijlstra
Objtool's --ibt option generates .ibt_endbr_seal which lists superfluous ENDBR instructions. That is those instructions for which the function is never indirectly called. Overwrite these ENDBR instructions with a NOP4 such that these function can never be indirect called, reducing the number of viable ENDBR targets in the kernel. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
2022-03-08x86/module: Fix the paravirt vs alternative orderPeter Zijlstra
Ever since commit 4e6292114c74 ("x86/paravirt: Add new features for paravirt patching") there is an ordering dependency between patching paravirt ops and patching alternatives, the module loader still violates this. Fixes: 4e6292114c74 ("x86/paravirt: Add new features for paravirt patching") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220303112825.068773913@infradead.org
2022-01-15mm: defer kmemleak object creation of module_alloc()Kefeng Wang
Yongqiang reports a kmemleak panic when module insmod/rmmod with KASAN enabled(without KASAN_VMALLOC) on x86[1]. When the module area allocates memory, it's kmemleak_object is created successfully, but the KASAN shadow memory of module allocation is not ready, so when kmemleak scan the module's pointer, it will panic due to no shadow memory with KASAN check. module_alloc __vmalloc_node_range kmemleak_vmalloc kmemleak_scan update_checksum kasan_module_alloc kmemleak_ignore Note, there is no problem if KASAN_VMALLOC enabled, the modules area entire shadow memory is preallocated. Thus, the bug only exits on ARCH which supports dynamic allocation of module area per module load, for now, only x86/arm64/s390 are involved. Add a VM_DEFER_KMEMLEAK flags, defer vmalloc'ed object register of kmemleak in module_alloc() to fix this issue. [1] https://lore.kernel.org/all/6d41e2b9-4692-5ec4-b1cd-cbe29ae89739@huawei.com/ [wangkefeng.wang@huawei.com: fix build] Link: https://lkml.kernel.org/r/20211125080307.27225-1-wangkefeng.wang@huawei.com [akpm@linux-foundation.org: simplify ifdefs, per Andrey] Link: https://lkml.kernel.org/r/CA+fCnZcnwJHUQq34VuRxpdoY6_XbJCDJ-jopksS5Eia4PijPzw@mail.gmail.com Link: https://lkml.kernel.org/r/20211124142034.192078-1-wangkefeng.wang@huawei.com Fixes: 793213a82de4 ("s390/kasan: dynamic shadow mem allocation for modules") Fixes: 39d114ddc682 ("arm64: add KASAN support") Fixes: bebf56a1b176 ("kasan: enable instrumentation of global variables") Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-28x86/alternative: Implement .retpoline_sites supportPeter Zijlstra
Rewrite retpoline thunk call sites to be indirect calls for spectre_v2=off. This ensures spectre_v2=off is as near to a RETPOLINE=n build as possible. This is the replacement for objtool writing alternative entries to ensure the same and achieves feature-parity with the previous approach. One noteworthy feature is that it relies on the thunks to be in machine order to compute the register index. Specifically, this does not yet address the Jcc __x86_indirect_thunk_* calls generated by clang, a future patch will add this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/r/20211026120310.232495794@infradead.org
2021-01-28x86/build: Treat R_386_PLT32 relocation as R_386_PC32Fangrui Song
This is similar to commit b21ebf2fb4cd ("x86: Treat R_X86_64_PLT32 as R_X86_64_PC32") but for i386. As far as the kernel is concerned, R_386_PLT32 can be treated the same as R_386_PC32. R_386_PLT32/R_X86_64_PLT32 are PC-relative relocation types which can only be used by branches. If the referenced symbol is defined externally, a PLT will be used. R_386_PC32/R_X86_64_PC32 are PC-relative relocation types which can be used by address taking operations and branches. If the referenced symbol is defined externally, a copy relocation/canonical PLT entry will be created in the executable. On x86-64, there is no PIC vs non-PIC PLT distinction and an R_X86_64_PLT32 relocation is produced for both `call/jmp foo` and `call/jmp foo@PLT` with newer (2018) GNU as/LLVM integrated assembler. This avoids canonical PLT entries (st_shndx=0, st_value!=0). On i386, there are 2 types of PLTs, PIC and non-PIC. Currently, the GCC/GNU as convention is to use R_386_PC32 for non-PIC PLT and R_386_PLT32 for PIC PLT. Copy relocations/canonical PLT entries are possible ABI issues but GCC/GNU as will likely keep the status quo because (1) the ABI is legacy (2) the change will drop a GNU ld diagnostic for non-default visibility ifunc in shared objects. clang-12 -fno-pic (since [1]) can emit R_386_PLT32 for compiler generated function declarations, because preventing canonical PLT entries is weighed over the rare ifunc diagnostic. Further info for the more interested: https://github.com/ClangBuiltLinux/linux/issues/1210 https://sourceware.org/bugzilla/show_bug.cgi?id=27169 https://github.com/llvm/llvm-project/commit/a084c0388e2a59b9556f2de0083333232da3f1d6 [1] [ bp: Massage commit message. ] Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Link: https://lkml.kernel.org/r/20210127205600.1227437-1-maskray@google.com
2020-06-09mm: don't include asm/pgtable.h if linux/mm.h is already includedMike Rapoport
Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h> in the files that include <linux/mm.h>. The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include <linux/mm.h>") ; do sed -i -e '/include <asm\/pgtable.h>/ d' $f done Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-08x86/module: Use text_mutex in apply_relocate_add()Josh Poimboeuf
Now that the livepatch code no longer needs the text_mutex for changing module permissions, move its usage down to apply_relocate_add(). Note the s390 version of apply_relocate_add() doesn't need to use the text_mutex because it already uses s390_kernel_write_lock, which accomplishes the same task. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08x86/module: Use text_poke() for late relocationsPeter Zijlstra
Because of late module patching, a livepatch module needs to be able to apply some of its relocations well after it has been loaded. Instead of playing games with module_{dis,en}able_ro(), use existing text poking mechanisms to apply relocations after module loading. So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first two also have STRICT_MODULE_RWX. This will allow removal of the last module_disable_ro() usage in livepatch. The ultimate goal is to completely disallow making executable mappings writable. [ jpoimboe: Split up patches. Use mod state to determine whether memcpy() can be used. Implement text_poke() for UML. ] Cc: x86@kernel.org Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-30x86/modules: Avoid breaking W^X while loading modulesNadav Amit
When modules and BPF filters are loaded, there is a time window in which some memory is both writable and executable. An attacker that has already found another vulnerability (e.g., a dangling pointer) might be able to exploit this behavior to overwrite kernel code. Prevent having writable executable PTEs in this stage. In addition, avoiding having W+X mappings can also slightly simplify the patching of modules code on initialization (e.g., by alternatives and static-key), as would be done in the next patch. This was actually the main motivation for this patch. To avoid having W+X mappings, set them initially as RW (NX) and after they are set as RO set them as X as well. Setting them as executable is done as a separate step to avoid one core in which the old PTE is cached (hence writable), and another which sees the updated PTE (executable), which would break the W^X protection. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Nadav Amit <namit@vmware.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <akpm@linux-foundation.org> Cc: <ard.biesheuvel@linaro.org> Cc: <deneen.t.dock@intel.com> Cc: <kernel-hardening@lists.openwall.com> Cc: <kristen@linux.intel.com> Cc: <linux_dti@icloud.com> Cc: <will.deacon@arm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jessica Yu <jeyu@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Rik van Riel <riel@surriel.com> Link: https://lkml.kernel.org/r/20190426001143.4983-12-namit@vmware.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-27x86: Add support for 64-bit place relative relocationsArd Biesheuvel
Add support for R_X86_64_PC64 relocations, which operate on 64-bit quantities holding a relative symbol reference. Also remove the definition of R_X86_64_NUM: given that it is currently unused, it is unclear what the new value should be. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jessica Yu <jeyu@kernel.org> Link: https://lkml.kernel.org/r/20180919065144.25010-5-ard.biesheuvel@linaro.org
2018-02-22x86: Treat R_X86_64_PLT32 as R_X86_64_PC32H.J. Lu
On i386, there are 2 types of PLTs, PIC and non-PIC. PIE and shared objects must use PIC PLT. To use PIC PLT, you need to load _GLOBAL_OFFSET_TABLE_ into EBX first. There is no need for that on x86-64 since x86-64 uses PC-relative PLT. On x86-64, for 32-bit PC-relative branches, we can generate PLT32 relocation, instead of PC32 relocation, which can also be used as a marker for 32-bit PC-relative branches. Linker can always reduce PLT32 relocation to PC32 if function is defined locally. Local functions should use PC32 relocation. As far as Linux kernel is concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32 since Linux kernel doesn't use PLT. R_X86_64_PLT32 for 32-bit PC-relative branches has been enabled in binutils master branch which will become binutils 2.31. [ hjl is working on having better documentation on this all, but a few more notes from him: "PLT32 relocation is used as marker for PC-relative branches. Because of EBX, it looks odd to generate PLT32 relocation on i386 when EBX doesn't have GOT. As for symbol resolution, PLT32 and PC32 relocations are almost interchangeable. But when linker sees PLT32 relocation against a protected symbol, it can resolved locally at link-time since it is used on a branch instruction. Linker can't do that for PC32 relocation" but for the kernel use, the two are basically the same, and this commit gets things building and working with the current binutils master - Linus ] Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-05x86/module: Detect and skip invalid relocationsJosh Poimboeuf
There have been some cases where external tooling (e.g., kpatch-build) creates a corrupt relocation which targets the wrong address. This is a silent failure which can corrupt memory in unexpected places. On x86, the bytes of data being overwritten by relocations are always initialized to zero beforehand. Use that knowledge to add sanity checks to detect such cases before they corrupt memory. Signed-off-by: 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: jeyu@kernel.org Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/37450d6c6225e54db107fba447ce9e56e5f758e9.1509713553.git.jpoimboe@redhat.com [ Restructured the messages, as it's unclear whether the relocation or the target is corrupted. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-26x86/unwind: Add the ORC unwinderJosh Poimboeuf
Add the new ORC unwinder which is enabled by CONFIG_ORC_UNWINDER=y. It plugs into the existing x86 unwinder framework. It relies on objtool to generate the needed .orc_unwind and .orc_unwind_ip sections. For more details on why ORC is used instead of DWARF, see Documentation/x86/orc-unwinder.txt - but the short version is that it's a simplified, fundamentally more robust debugninfo data structure, which also allows up to two orders of magnitude faster lookups than the DWARF unwinder - which matters to profiling workloads like perf. Thanks to Andy Lutomirski for the performance improvement ideas: splitting the ORC unwind table into two parallel arrays and creating a fast lookup table to search a subset of the unwind table. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.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: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/0a6cbfb40f8da99b7a45a1a8302dc6aef16ec812.1500938583.git.jpoimboe@redhat.com [ Extended the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-08mm, vmalloc: use __GFP_HIGHMEM implicitlyMichal Hocko
__vmalloc* allows users to provide gfp flags for the underlying allocation. This API is quite popular $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l 77 The only problem is that many people are not aware that they really want to give __GFP_HIGHMEM along with other flags because there is really no reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages which are mapped to the kernel vmalloc space. About half of users don't use this flag, though. This signals that we make the API unnecessarily too complex. This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM are simplified and drop the flag. Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Cristopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-29x86/asm: Stop depending on ptrace.h in alternative.hAndy Lutomirski
alternative.h pulls in ptrace.h, which means that alternatives can't be used in anything referenced from ptrace.h, which is a mess. Break the dependency by pulling text patching helpers into their own header. Signed-off-by: Andy Lutomirski <luto@kernel.org> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03x86/mm/KASLR: Propagate KASLR status to kernel properBorislav Petkov
Commit: e2b32e678513 ("x86, kaslr: randomize module base load address") made module base address randomization unconditional and didn't regard disabled KKASLR due to CONFIG_HIBERNATION and command line option "nokaslr". For more info see (now reverted) commit: f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation") In order to propagate KASLR status to kernel proper, we need a single bit in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the top-down allocated bits for bits supposed to be used by the bootloader. Originally-From: Jiri Kosina <jkosina@suse.cz> Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-16Revert "x86/mm/ASLR: Propagate base load address calculation"Borislav Petkov
This reverts commit: f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation") The main reason for the revert is that the new boot flag does not work at all currently, and in order to make this work, we need non-trivial changes to the x86 boot code which we didn't manage to get done in time for merging. And even if we did, they would've been too risky so instead of rushing things and break booting 4.1 on boxes left and right, we will be very strict and conservative and will take our time with this to fix and test it properly. Reported-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: H. Peter Anvin <hpa@linux.intel.com Cc: Jiri Kosina <jkosina@suse.cz> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Junjie Mao <eternal.n08@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt.fleming@intel.com> Link: http://lkml.kernel.org/r/20150316100628.GD22995@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-21Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull misc x86 fixes from Ingo Molnar: "This contains: - EFI fixes - a boot printout fix - ASLR/kASLR fixes - intel microcode driver fixes - other misc fixes Most of the linecount comes from an EFI revert" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch x86/microcode/intel: Handle truncated microcode images more robustly x86/microcode/intel: Guard against stack overflow in the loader x86, mm/ASLR: Fix stack randomization on 64-bit systems x86/mm/init: Fix incorrect page size in init_memory_mapping() printks x86/mm/ASLR: Propagate base load address calculation Documentation/x86: Fix path in zero-page.txt x86/apic: Fix the devicetree build in certain configs Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes" x86/efi: Avoid triple faults during EFI mixed mode calls
2015-02-20x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarchJiri Kosina
Commit f47233c2d34 ("x86/mm/ASLR: Propagate base load address calculation") causes PAGE_SIZE redefinition warnings for UML subarch builds. This is caused by added includes that were leftovers from previous patch versions are are not actually needed (especially page_types.h inlcude in module.c). Drop those stray includes. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@suse.de> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1502201017240.28769@pobox.suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-19x86/mm/ASLR: Propagate base load address calculationJiri Kosina
Commit: e2b32e678513 ("x86, kaslr: randomize module base load address") makes the base address for module to be unconditionally randomized in case when CONFIG_RANDOMIZE_BASE is defined and "nokaslr" option isn't present on the commandline. This is not consistent with how choose_kernel_location() decides whether it will randomize kernel load base. Namely, CONFIG_HIBERNATION disables kASLR (unless "kaslr" option is explicitly specified on kernel commandline), which makes the state space larger than what module loader is looking at. IOW CONFIG_HIBERNATION && CONFIG_RANDOMIZE_BASE is a valid config option, kASLR wouldn't be applied by default in that case, but module loader is not aware of that. Instead of fixing the logic in module.c, this patch takes more generic aproach. It introduces a new bootparam setup data_type SETUP_KASLR and uses that to pass the information whether kaslr has been applied during kernel decompression, and sets a global 'kaslr_enabled' variable accordingly, so that any kernel code (module loading, livepatching, ...) can make decisions based on its value. x86 module loader is converted to make use of this flag. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Kees Cook <keescook@chromium.org> Cc: "H. Peter Anvin" <hpa@linux.intel.com> Link: https://lkml.kernel.org/r/alpine.LNX.2.00.1502101411280.10719@pobox.suse.cz [ Always dump correct kaslr status when panicking ] Signed-off-by: Borislav Petkov <bp@suse.de>
2015-02-13kasan: enable instrumentation of global variablesAndrey Ryabinin
This feature let us to detect accesses out of bounds of global variables. This will work as for globals in kernel image, so for globals in modules. Currently this won't work for symbols in user-specified sections (e.g. __init, __read_mostly, ...) The idea of this is simple. Compiler increases each global variable by redzone size and add constructors invoking __asan_register_globals() function. Information about global variable (address, size, size with redzone ...) passed to __asan_register_globals() so we could poison variable's redzone. This patch also forces module_alloc() to return 8*PAGE_SIZE aligned address making shadow memory handling ( kasan_module_alloc()/kasan_module_free() ) more simple. Such alignment guarantees that each shadow page backing modules address space correspond to only one module_alloc() allocation. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13mm: vmalloc: pass additional vm_flags to __vmalloc_node_range()Andrey Ryabinin
For instrumenting global variables KASan will shadow memory backing memory for modules. So on module loading we will need to allocate memory for shadow and map it at address in shadow that corresponds to the address allocated in module_alloc(). __vmalloc_node_range() could be used for this purpose, except it puts a guard hole after allocated area. Guard hole in shadow memory should be a problem because at some future point we might need to have a shadow memory at address occupied by guard hole. So we could fail to allocate shadow for module_alloc(). Now we have VM_NO_GUARD flag disabling guard page, so we need to pass into __vmalloc_node_range(). Add new parameter 'vm_flags' to __vmalloc_node_range() function. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-24x86, kaslr: fix module lock ordering problemKees Cook
There was a potential lock ordering problem with the module kASLR patch ("x86, kaslr: randomize module base load address"). This patch removes the usage of the module_mutex and creates a new mutex to protect the module base address offset value. Chain exists of: text_mutex --> kprobe_insn_slots.mutex --> module_mutex [ 0.515561] Possible unsafe locking scenario: [ 0.515561] [ 0.515561] CPU0 CPU1 [ 0.515561] ---- ---- [ 0.515561] lock(module_mutex); [ 0.515561] lock(kprobe_insn_slots.mutex); [ 0.515561] lock(module_mutex); [ 0.515561] lock(text_mutex); [ 0.515561] [ 0.515561] *** DEADLOCK *** Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andy Honig <ahonig@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-02-25x86, kaslr: randomize module base load addressKees Cook
Randomize the load address of modules in the kernel to make kASLR effective for modules. Modules can only be loaded within a particular range of virtual address space. This patch adds 10 bits of entropy to the load address by adding 1-1024 * PAGE_SIZE to the beginning range where modules are loaded. The single base offset was chosen because randomizing each module load ends up wasting/fragmenting memory too much. Prior approaches to minimizing fragmentation while doing randomization tend to result in worse entropy than just doing a single base address offset. Example kASLR boot without this change, with a single module loaded: ---[ Modules ]--- 0xffffffffc0000000-0xffffffffc0001000 4K ro GLB x pte 0xffffffffc0001000-0xffffffffc0002000 4K ro GLB NX pte 0xffffffffc0002000-0xffffffffc0004000 8K RW GLB NX pte 0xffffffffc0004000-0xffffffffc0200000 2032K pte 0xffffffffc0200000-0xffffffffff000000 1006M pmd ---[ End Modules ]--- Example kASLR boot after this change, same module loaded: ---[ Modules ]--- 0xffffffffc0000000-0xffffffffc0200000 2M pmd 0xffffffffc0200000-0xffffffffc03bf000 1788K pte 0xffffffffc03bf000-0xffffffffc03c0000 4K ro GLB x pte 0xffffffffc03c0000-0xffffffffc03c1000 4K ro GLB NX pte 0xffffffffc03c1000-0xffffffffc03c3000 8K RW GLB NX pte 0xffffffffc03c3000-0xffffffffc0400000 244K pte 0xffffffffc0400000-0xffffffffff000000 1004M pmd ---[ End Modules ]--- Signed-off-by: Andy Honig <ahonig@google.com> Link: http://lkml.kernel.org/r/20140226005916.GA27083@www.outflux.net Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-11-13mm/arch: use NUMA_NO_NODEJianguo Wu
Use more appropriate NUMA_NO_NODE instead of -1 in all archs' module_alloc() Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-24Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree from Jiri Kosina: "Trivial updates all over the place as usual." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (29 commits) Fix typo in include/linux/clk.h . pci: hotplug: Fix typo in pci iommu: Fix typo in iommu video: Fix typo in drivers/video Documentation: Add newline at end-of-file to files lacking one arm,unicore32: Remove obsolete "select MISC_DEVICES" module.c: spelling s/postition/position/g cpufreq: Fix typo in cpufreq driver trivial: typo in comment in mksysmap mach-omap2: Fix typo in debug message and comment scsi: aha152x: Fix sparse warning and make printing pointer address more portable. Change email address for Steve Glendinning Btrfs: fix typo in convert_extent_bit via: Remove bogus if check netprio_cgroup.c: fix comment typo backlight: fix memory leak on obscure error path Documentation: asus-laptop.txt references an obsolete Kconfig item Documentation: ManagementStyle: fixed typo mm/vmscan: cleanup comment error in balance_pgdat mm: cleanup on the comments of zone_reclaim_stat ...
2012-07-20module.c: spelling s/postition/position/gGeert Uytterhoeven
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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