- Linux-kselftest-mirror - lists.linaro.org

[PATCH] selftests/futex: skip tests if shmget unsupported

by Carlos Llamas

On systems where the shmget() syscall is not supported, tests like anon_page and shared_waitv will fail. Skip these tests in such cases to allow the rest of the test suite to run. Signed-off-by: Carlos Llamas <cmllamas(a)google.com> --- tools/testing/selftests/futex/functional/futex_wait.c | 2 ++ tools/testing/selftests/futex/functional/futex_waitv.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 152ca4612886..1269642bb662 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -71,6 +71,8 @@ TEST(anon_page) /* Testing an anon page shared memory */ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) { + if (errno == ENOSYS) + ksft_exit_skip("shmget syscall not supported\n"); perror("shmget"); exit(1); } diff --git a/tools/testing/selftests/futex/functional/futex_waitv.c b/tools/testing/selftests/futex/functional/futex_waitv.c index c684b10eb76e..3bc4e5dc70e7 100644 --- a/tools/testing/selftests/futex/functional/futex_waitv.c +++ b/tools/testing/selftests/futex/functional/futex_waitv.c @@ -86,6 +86,8 @@ TEST(shared_waitv) int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) { + if (errno == ENOSYS) + ksft_exit_skip("shmget syscall not supported\n"); perror("shmget"); exit(1); } -- 2.51.0.869.ge66316f041-goog

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[PATCH v20 00/28] riscv control-flow integrity for usermode

by Deepak Gupta

Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ To: Thomas Gleixner <tglx(a)linutronix.de> To: Ingo Molnar <mingo(a)redhat.com> To: Borislav Petkov <bp(a)alien8.de> To: Dave Hansen <dave.hansen(a)linux.intel.com> To: x86(a)kernel.org To: H. Peter Anvin <hpa(a)zytor.com> To: Andrew Morton <akpm(a)linux-foundation.org> To: Liam R. Howlett <Liam.Howlett(a)oracle.com> To: Vlastimil Babka <vbabka(a)suse.cz> To: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> To: Paul Walmsley <paul.walmsley(a)sifive.com> To: Palmer Dabbelt <palmer(a)dabbelt.com> To: Albert Ou <aou(a)eecs.berkeley.edu> To: Conor Dooley <conor(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Arnd Bergmann <arnd(a)arndb.de> To: Christian Brauner <brauner(a)kernel.org> To: Peter Zijlstra <peterz(a)infradead.org> To: Oleg Nesterov <oleg(a)redhat.com> To: Eric Biederman <ebiederm(a)xmission.com> To: Kees Cook <kees(a)kernel.org> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> To: Jann Horn <jannh(a)google.com> To: Conor Dooley <conor+dt(a)kernel.org> To: Miguel Ojeda <ojeda(a)kernel.org> To: Alex Gaynor <alex.gaynor(a)gmail.com> To: Boqun Feng <boqun.feng(a)gmail.com> To: Gary Guo <gary(a)garyguo.net> To: Björn Roy Baron <bjorn3_gh(a)protonmail.com> To: Benno Lossin <benno.lossin(a)proton.me> To: Andreas Hindborg <a.hindborg(a)kernel.org> To: Alice Ryhl <aliceryhl(a)google.com> To: Trevor Gross <tmgross(a)umich.edu> Cc: linux-kernel(a)vger.kernel.org Cc: linux-fsdevel(a)vger.kernel.org Cc: linux-mm(a)kvack.org Cc: linux-riscv(a)lists.infradead.org Cc: devicetree(a)vger.kernel.org Cc: linux-arch(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Cc: alistair.francis(a)wdc.com Cc: richard.henderson(a)linaro.org Cc: jim.shu(a)sifive.com Cc: andybnac(a)gmail.com Cc: kito.cheng(a)sifive.com Cc: charlie(a)rivosinc.com Cc: atishp(a)rivosinc.com Cc: evan(a)rivosinc.com Cc: cleger(a)rivosinc.com Cc: alexghiti(a)rivosinc.com Cc: samitolvanen(a)google.com Cc: broonie(a)kernel.org Cc: rick.p.edgecombe(a)intel.com Cc: rust-for-linux(a)vger.kernel.org changelog --------- v20: - rebased on v6.18-rc1. - Added two vDSO support. If `CONFIG_RISCV_USER_CFI` is selected two vDSOs are compiled (one for hardware prior to RVA23 and one for RVA23 onwards). Kernel exposes RVA23 vDSO if hardware/cpu implements zimop else exposes existing vDSO to userspace. - default selection for `CONFIG_RISCV_USER_CFI` is "Yes". - replaced "__ASSEMBLY__" with "__ASSEMBLER__" v19: - riscv_nousercfi was `int`. changed it to unsigned long. Thanks to Alex Ghiti for reporting it. It was a bug. - ELP is cleared on trap entry only when CONFIG_64BIT. - restore ssp back on return to usermode was being done before `riscv_v_context_nesting_end` on trap exit path. If kernel shadow stack were enabled this would result in kernel operating on user shadow stack and panic (as I found in my testing of kcfi patch series). So fixed that. v18: - rebased on 6.16-rc1 - uprobe handling clears ELP in sstatus image in pt_regs - vdso was missing shadow stack elf note for object files. added that. Additional asm file for vdso needed the elf marker flag. toolchain should complain if `-fcf-protection=full` and marker is missing for object generated from asm file. Asked toolchain folks to fix this. Although no reason to gate the merge on that. - Split up compile options for march and fcf-protection in vdso Makefile - CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu Added `arch/riscv/configs/hardening.config` fragment which selects CONFIG_RISCV_USER_CFI v17: - fixed warnings due to empty macros in usercfi.h (reported by alexg) - fixed prefixes in commit titles reported by alexg - took below uprobe with fcfi v2 patch from Zong Li and squashed it with "riscv/traps: Introduce software check exception and uprobe handling" https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ v16: - If FWFT is not implemented or returns error for shadow stack activation, then no_usercfi is set to disable shadow stack. Although this should be picked up by extension validation and activation. Fixed this bug for zicfilp and zicfiss both. Thanks to Charlie Jenkins for reporting this. - If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by Charlie Jenkins. - Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to keep it off till we have more hardware availibility with RVA23 profile and zimop/zcmop implemented. Else this will start breaking people's workflow - Includes the fix if "!RV64 and !SBI" then definitions for FWFT in asm-offsets.c error. v15: - Toolchain has been updated to include `-fcf-protection` flag. This exists for x86 as well. Updated kernel patches to compile vDSO and selftest to compile with `fcf-protection=full` flag. - selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. - Patch to enable shadow stack for kernel wasn't hidden behind CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. v14: - rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. - Took Radim's suggestions on bitfields. - Placed cfi_state at the end of thread_info block so that current situation is not disturbed with respect to member fields of thread_info in single cacheline. v13: - cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses riscv_has_extension_unlikely() - uses nops(count) to create nop slide - RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it - changed ternaries to simply use implicit casting to convert to bool. - kernel command line allows to disable zicfilp and zicfiss independently. updated kernel-parameters.txt. - ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace kselftest. - cosmetic and grammatical changes to documentation. v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- Changes in v20: - Link to v19: https://lore.kernel.org/r/20250731-v5_user_cfi_series-v19-0-09b468d7beab@ri… Changes in v19: - Link to v18: https://lore.kernel.org/r/20250711-v5_user_cfi_series-v18-0-a8ee62f9f38e@ri… Changes in v18: - Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@ri… Changes in v17: - Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@ri… Changes in v16: - Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@ri… Changes in v15: - changelog posted just below cover letter - Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@ri… Changes in v14: - changelog posted just below cover letter - Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@ri… Changes in v13: - changelog posted just below cover letter - Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@ri… Changes in v12: - changelog posted just below cover letter - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - changelog posted just below cover letter - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Deepak Gupta (26): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv/mm: manufacture shadow stack pte riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs riscv/mm: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception and uprobe handling riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: kernel command line option to opt out of user cfi riscv: enable kernel access to shadow stack memory via FWFT sbi call arch/riscv: dual vdso creation logic and select vdso based on hw riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad and shadow stack note Documentation/admin-guide/kernel-parameters.txt | 8 + Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 179 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 21 + arch/riscv/Makefile | 8 +- arch/riscv/configs/hardening.config | 4 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 12 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 26 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 95 ++++ arch/riscv/include/asm/vdso.h | 7 +- arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 34 ++ arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 2 + arch/riscv/kernel/asm-offsets.c | 10 + arch/riscv/kernel/cpufeature.c | 27 + arch/riscv/kernel/entry.S | 38 ++ arch/riscv/kernel/head.S | 27 + arch/riscv/kernel/process.c | 27 +- arch/riscv/kernel/ptrace.c | 95 ++++ arch/riscv/kernel/signal.c | 148 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 54 ++ arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ arch/riscv/kernel/vdso.c | 7 + arch/riscv/kernel/vdso/Makefile | 40 +- arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/gen_vdso_offsets.sh | 4 +- arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/note.S | 3 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- arch/riscv/kernel/vdso_cfi/Makefile | 25 + arch/riscv/kernel/vdso_cfi/vdso-cfi.S | 11 + arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 16 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 2 + include/uapi/linux/prctl.h | 27 + kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 16 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + 62 files changed, 2468 insertions(+), 41 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - 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[PATCH v21 00/28] riscv control-flow integrity for usermode

by Deepak Gupta

v21: fixed build errors. Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ To: Thomas Gleixner <tglx(a)linutronix.de> To: Ingo Molnar <mingo(a)redhat.com> To: Borislav Petkov <bp(a)alien8.de> To: Dave Hansen <dave.hansen(a)linux.intel.com> To: x86(a)kernel.org To: H. Peter Anvin <hpa(a)zytor.com> To: Andrew Morton <akpm(a)linux-foundation.org> To: Liam R. Howlett <Liam.Howlett(a)oracle.com> To: Vlastimil Babka <vbabka(a)suse.cz> To: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> To: Paul Walmsley <paul.walmsley(a)sifive.com> To: Palmer Dabbelt <palmer(a)dabbelt.com> To: Albert Ou <aou(a)eecs.berkeley.edu> To: Conor Dooley <conor(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Arnd Bergmann <arnd(a)arndb.de> To: Christian Brauner <brauner(a)kernel.org> To: Peter Zijlstra <peterz(a)infradead.org> To: Oleg Nesterov <oleg(a)redhat.com> To: Eric Biederman <ebiederm(a)xmission.com> To: Kees Cook <kees(a)kernel.org> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> To: Jann Horn <jannh(a)google.com> To: Conor Dooley <conor+dt(a)kernel.org> To: Miguel Ojeda <ojeda(a)kernel.org> To: Alex Gaynor <alex.gaynor(a)gmail.com> To: Boqun Feng <boqun.feng(a)gmail.com> To: Gary Guo <gary(a)garyguo.net> To: Björn Roy Baron <bjorn3_gh(a)protonmail.com> To: Benno Lossin <benno.lossin(a)proton.me> To: Andreas Hindborg <a.hindborg(a)kernel.org> To: Alice Ryhl <aliceryhl(a)google.com> To: Trevor Gross <tmgross(a)umich.edu> Cc: linux-kernel(a)vger.kernel.org Cc: linux-fsdevel(a)vger.kernel.org Cc: linux-mm(a)kvack.org Cc: linux-riscv(a)lists.infradead.org Cc: devicetree(a)vger.kernel.org Cc: linux-arch(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Cc: alistair.francis(a)wdc.com Cc: richard.henderson(a)linaro.org Cc: jim.shu(a)sifive.com Cc: andybnac(a)gmail.com Cc: kito.cheng(a)sifive.com Cc: charlie(a)rivosinc.com Cc: atishp(a)rivosinc.com Cc: evan(a)rivosinc.com Cc: cleger(a)rivosinc.com Cc: alexghiti(a)rivosinc.com Cc: samitolvanen(a)google.com Cc: broonie(a)kernel.org Cc: rick.p.edgecombe(a)intel.com Cc: rust-for-linux(a)vger.kernel.org changelog --------- v21: - Fixing build errors due to changes in arch/riscv/include/asm/vdso.h Using #ifdef instead of IS_ENABLED in arch/riscv/include/asm/vdso.h vdso-cfi-offsets.h should be included only when CONFIG_RISCV_USER_CFI is selected. v20: - rebased on v6.18-rc1. - Added two vDSO support. If `CONFIG_RISCV_USER_CFI` is selected two vDSOs are compiled (one for hardware prior to RVA23 and one for RVA23 onwards). Kernel exposes RVA23 vDSO if hardware/cpu implements zimop else exposes existing vDSO to userspace. - default selection for `CONFIG_RISCV_USER_CFI` is "Yes". - replaced "__ASSEMBLY__" with "__ASSEMBLER__" v19: - riscv_nousercfi was `int`. changed it to unsigned long. Thanks to Alex Ghiti for reporting it. It was a bug. - ELP is cleared on trap entry only when CONFIG_64BIT. - restore ssp back on return to usermode was being done before `riscv_v_context_nesting_end` on trap exit path. If kernel shadow stack were enabled this would result in kernel operating on user shadow stack and panic (as I found in my testing of kcfi patch series). So fixed that. v18: - rebased on 6.16-rc1 - uprobe handling clears ELP in sstatus image in pt_regs - vdso was missing shadow stack elf note for object files. added that. Additional asm file for vdso needed the elf marker flag. toolchain should complain if `-fcf-protection=full` and marker is missing for object generated from asm file. Asked toolchain folks to fix this. Although no reason to gate the merge on that. - Split up compile options for march and fcf-protection in vdso Makefile - CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu Added `arch/riscv/configs/hardening.config` fragment which selects CONFIG_RISCV_USER_CFI v17: - fixed warnings due to empty macros in usercfi.h (reported by alexg) - fixed prefixes in commit titles reported by alexg - took below uprobe with fcfi v2 patch from Zong Li and squashed it with "riscv/traps: Introduce software check exception and uprobe handling" https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ v16: - If FWFT is not implemented or returns error for shadow stack activation, then no_usercfi is set to disable shadow stack. Although this should be picked up by extension validation and activation. Fixed this bug for zicfilp and zicfiss both. Thanks to Charlie Jenkins for reporting this. - If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by Charlie Jenkins. - Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to keep it off till we have more hardware availibility with RVA23 profile and zimop/zcmop implemented. Else this will start breaking people's workflow - Includes the fix if "!RV64 and !SBI" then definitions for FWFT in asm-offsets.c error. v15: - Toolchain has been updated to include `-fcf-protection` flag. This exists for x86 as well. Updated kernel patches to compile vDSO and selftest to compile with `fcf-protection=full` flag. - selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. - Patch to enable shadow stack for kernel wasn't hidden behind CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. v14: - rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. - Took Radim's suggestions on bitfields. - Placed cfi_state at the end of thread_info block so that current situation is not disturbed with respect to member fields of thread_info in single cacheline. v13: - cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses riscv_has_extension_unlikely() - uses nops(count) to create nop slide - RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it - changed ternaries to simply use implicit casting to convert to bool. - kernel command line allows to disable zicfilp and zicfiss independently. updated kernel-parameters.txt. - ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace kselftest. - cosmetic and grammatical changes to documentation. v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- Changes in v21: - Link to v20: https://lore.kernel.org/r/20251013-v5_user_cfi_series-v20-0-b9de4be9912e@ri… Changes in v20: - Link to v19: https://lore.kernel.org/r/20250731-v5_user_cfi_series-v19-0-09b468d7beab@ri… Changes in v19: - Link to v18: https://lore.kernel.org/r/20250711-v5_user_cfi_series-v18-0-a8ee62f9f38e@ri… Changes in v18: - Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@ri… Changes in v17: - Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@ri… Changes in v16: - Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@ri… Changes in v15: - changelog posted just below cover letter - Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@ri… Changes in v14: - changelog posted just below cover letter - Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@ri… Changes in v13: - changelog posted just below cover letter - Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@ri… Changes in v12: - changelog posted just below cover letter - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - changelog posted just below cover letter - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Deepak Gupta (26): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv/mm: manufacture shadow stack pte riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs riscv/mm: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception and uprobe handling riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: kernel command line option to opt out of user cfi riscv: enable kernel access to shadow stack memory via FWFT sbi call arch/riscv: dual vdso creation logic and select vdso based on hw riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad and shadow stack note Documentation/admin-guide/kernel-parameters.txt | 8 + Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 179 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 21 + arch/riscv/Makefile | 8 +- arch/riscv/configs/hardening.config | 4 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 12 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 26 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 95 ++++ arch/riscv/include/asm/vdso.h | 13 +- arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 34 ++ arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 2 + arch/riscv/kernel/asm-offsets.c | 10 + arch/riscv/kernel/cpufeature.c | 27 + arch/riscv/kernel/entry.S | 38 ++ arch/riscv/kernel/head.S | 27 + arch/riscv/kernel/process.c | 27 +- arch/riscv/kernel/ptrace.c | 95 ++++ arch/riscv/kernel/signal.c | 148 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 54 ++ arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ arch/riscv/kernel/vdso.c | 7 + arch/riscv/kernel/vdso/Makefile | 40 +- arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/gen_vdso_offsets.sh | 4 +- arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/note.S | 3 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- arch/riscv/kernel/vdso_cfi/Makefile | 25 + arch/riscv/kernel/vdso_cfi/vdso-cfi.S | 11 + arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 16 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 2 + include/uapi/linux/prctl.h | 27 + kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 16 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + 62 files changed, 2474 insertions(+), 41 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - debug

1 week, 1 day

2
30
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[PATCH v2 00/19] rust: replace `kernel::c_str!` with C-Strings

by Tamir Duberstein

This series depends on step 3[0]. Subsystem maintainers: I would appreciate your `Acked-by`s so that this can be taken through Miguel's tree (where the previous series must go). Link: https://lore.kernel.org/all/20250925-cstr-core-v16-0-5cdcb3470ec2@gmail.com/ [0] Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v2: - Rebase. - Add two patches to address new code. - Drop incorrectly applied Acked-by tags from Danilo. - Link to v1: https://lore.kernel.org/r/20250710-core-cstr-cstrings-v1-0-027420ea799e@gma… --- Tamir Duberstein (19): drivers: net: replace `kernel::c_str!` with C-Strings gpu: nova-core: replace `kernel::c_str!` with C-Strings rust: auxiliary: replace `kernel::c_str!` with C-Strings rust: clk: replace `kernel::c_str!` with C-Strings rust: configfs: replace `kernel::c_str!` with C-Strings rust: cpufreq: replace `kernel::c_str!` with C-Strings rust: device: replace `kernel::c_str!` with C-Strings rust: firmware: replace `kernel::c_str!` with C-Strings rust: kunit: replace `kernel::c_str!` with C-Strings rust: macros: replace `kernel::c_str!` with C-Strings rust: miscdevice: replace `kernel::c_str!` with C-Strings rust: net: replace `kernel::c_str!` with C-Strings rust: pci: replace `kernel::c_str!` with C-Strings rust: platform: replace `kernel::c_str!` with C-Strings rust: seq_file: replace `kernel::c_str!` with C-Strings rust: str: replace `kernel::c_str!` with C-Strings rust: sync: replace `kernel::c_str!` with C-Strings rust: io: replace `kernel::c_str!` with C-Strings rust: regulator: replace `kernel::c_str!` with C-Strings drivers/block/rnull.rs | 2 +- drivers/cpufreq/rcpufreq_dt.rs | 5 ++--- drivers/gpu/drm/nova/driver.rs | 10 +++++----- drivers/gpu/nova-core/driver.rs | 6 +++--- drivers/net/phy/ax88796b_rust.rs | 7 +++---- drivers/net/phy/qt2025.rs | 5 ++--- rust/kernel/clk.rs | 6 ++---- rust/kernel/configfs.rs | 9 +++++---- rust/kernel/cpufreq.rs | 3 +-- rust/kernel/device.rs | 4 +--- rust/kernel/device/property.rs | 6 +++--- rust/kernel/firmware.rs | 6 +++--- rust/kernel/io/mem.rs | 7 +++---- rust/kernel/kunit.rs | 11 ++++------- rust/kernel/net/phy.rs | 6 ++---- rust/kernel/platform.rs | 6 +++--- rust/kernel/regulator.rs | 9 +++------ rust/kernel/seq_file.rs | 4 ++-- rust/kernel/str.rs | 5 ++--- rust/kernel/sync.rs | 5 ++--- rust/kernel/sync/completion.rs | 2 +- rust/kernel/workqueue.rs | 8 ++++---- rust/macros/kunit.rs | 10 +++++----- rust/macros/module.rs | 2 +- samples/rust/rust_configfs.rs | 5 ++--- samples/rust/rust_driver_auxiliary.rs | 4 ++-- samples/rust/rust_driver_faux.rs | 4 ++-- samples/rust/rust_driver_pci.rs | 4 ++-- samples/rust/rust_driver_platform.rs | 30 ++++++++++++++---------------- samples/rust/rust_misc_device.rs | 3 +-- scripts/rustdoc_test_gen.rs | 4 ++-- 31 files changed, 88 insertions(+), 110 deletions(-) --- base-commit: f3f6b3664302e16ef1c6b91034a72df5564d6b8a change-id: 20250710-core-cstr-cstrings-1faaa632f0fd prerequisite-change-id: 20250201-cstr-core-d4b9b69120cf:v16 prerequisite-patch-id: e0ca756f740ab0ce7478bbf6510948ba89529a2f prerequisite-patch-id: 6d8dbdf864f79fc0c2820e702a7cb87753649ca0 prerequisite-patch-id: 7d4d1d036043a85dcbaf0d09ea85768120efe094 Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

1 week, 1 day

7
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[PATCH v2 0/3] arm64/sme: Support disabling streaming mode via ptrace on SME only systems

by Mark Brown

Currently it is not possible to disable streaming mode via ptrace on SME only systems, the interface for doing this is to write via NT_ARM_SVE but such writes will be rejected on a system without SVE support. Enable this functionality by allowing userspace to write SVE_PT_REGS_FPSIMD format data via NT_ARM_SVE with the vector length set to 0 on SME only systems. Such writes currently error since we require that a vector length is specified which should minimise the risk that existing software is relying on current behaviour. Reads are not supported since I am not aware of any use case for this and there is some risk that an existing userspace application may be confused if it reads NT_ARM_SVE on a system without SVE. Existing kernels will return FPSIMD formatted register state from NT_ARM_SVE if full SVE state is not stored, for example if the task has not used SVE. Returning a vector length of 0 would create a risk that software could try to do things like allocate space for register state with zero sizes, while returning a vector length of 128 bits would look like SVE is supported. It seems safer to just not make the changes to add read support. It remains possible for userspace to detect a SME only system via the ptrace interface only since reads of NT_ARM_SSVE and NT_ARM_ZA will suceed while reads of NT_ARM_SVE will fail. Read/write access to the FPSIMD registers in non-streaming mode is available via REGSET_FPR. The aim is is to make a minimally invasive change, no operation that would previously have succeeded will be affected, and we use a previously defined interface in new circumstances rather than define completely new ABI. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v2: - Rebase onto v6.18-rc1 - Link to v1: https://lore.kernel.org/r/20250820-arm64-sme-ptrace-sme-only-v1-0-f7c22b287… --- Mark Brown (3): arm64/sme: Support disabling streaming mode via ptrace on SME only systems kselftst/arm64: Test NT_ARM_SVE FPSIMD format writes on non-SVE systems kselftest/arm64: Cover disabling streaming mode without SVE in fp-ptrace Documentation/arch/arm64/sve.rst | 5 +++ arch/arm64/kernel/ptrace.c | 40 +++++++++++++++--- tools/testing/selftests/arm64/fp/fp-ptrace.c | 5 +-- tools/testing/selftests/arm64/fp/sve-ptrace.c | 61 +++++++++++++++++++++++++++ 4 files changed, 100 insertions(+), 11 deletions(-) --- base-commit: cb6649f6217c0331b885cf787f1d175963e2a1d2 change-id: 20250717-arm64-sme-ptrace-sme-only-1fb850600ea0 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 week, 2 days

1
3
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[PATCH] selftests/futex: add newline to ksft_exit_fail_msg()

by Carlos Llamas

This was missed in commit e5c04d0f3ea0 ("selftests/futex: Refactor futex_wait with kselftest_harness.h") while replacing previous perror() calls, which automatically append the newline character. Fixes: e5c04d0f3ea0 ("selftests/futex: Refactor futex_wait with kselftest_harness.h") Signed-off-by: Carlos Llamas <cmllamas(a)google.com> --- tools/testing/selftests/futex/functional/futex_wait.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 152ca4612886..4cd87f2a3422 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -108,14 +108,14 @@ TEST(file_backed) /* Testing a file backed shared memory */ fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); if (fd < 0) - ksft_exit_fail_msg("open"); + ksft_exit_fail_msg("open\n"); if (ftruncate(fd, sizeof(f_private))) - ksft_exit_fail_msg("ftruncate"); + ksft_exit_fail_msg("ftruncate\n"); shm = mmap(NULL, sizeof(f_private), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (shm == MAP_FAILED) - ksft_exit_fail_msg("mmap"); + ksft_exit_fail_msg("mmap\n"); memcpy(shm, &f_private, sizeof(f_private)); -- 2.51.0.869.ge66316f041-goog

1 week, 2 days

1
0
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[PATCH v2 0/7] iommufd: Add MSI mapping support with nested SMMU (Part-2 RMR)

by Nicolin Chen

[ Background ] On ARM GIC systems and others, the target address of the MSI is translated by the IOMMU. For GIC, the MSI address page is called "ITS" page. When the IOMMU is disabled, the MSI address is programmed to the physical location of the GIC ITS page (e.g. 0x20200000). When the IOMMU is enabled, the ITS page is behind the IOMMU, so the MSI address is programmed to an allocated IO virtual address (a.k.a IOVA), e.g. 0xFFFF0000, which must be mapped to the physical ITS page: IOVA (0xFFFF0000) ===> PA (0x20200000). When a 2-stage translation is enabled, IOVA will be still used to program the MSI address, though the mappings will be in two stages: IOVA (0xFFFF0000) ===> IPA (e.g. 0x80900000) ===> PA (0x20200000) (IPA stands for Intermediate Physical Address). If the device that generates MSI is attached to an IOMMU_DOMAIN_DMA, the IOVA is dynamically allocated from the top of the IOVA space. If attached to an IOMMU_DOMAIN_UNMANAGED (e.g. a VFIO passthrough device), the IOVA is fixed to an MSI window reported by the IOMMU driver via IOMMU_RESV_SW_MSI, which is hardwired to MSI_IOVA_BASE (IOVA==0x8000000) for ARM IOMMUs. So far, this IOMMU_RESV_SW_MSI works well as kernel is entirely in charge of the IOMMU translation (1-stage translation), since the IOVA for the ITS page is fixed and known by kernel. However, with virtual machine enabling a nested IOMMU translation (2-stage), a guest kernel directly controls the stage-1 translation with an IOMMU_DOMAIN_DMA, mapping a vITS page (at an IPA 0x80900000) onto its own IOVA space (e.g. 0xEEEE0000). Then, the host kernel can't know that guest-level IOVA to program the MSI address. There have been two approaches to solve this problem: 1. Create an identity mapping in the stage-1. VMM could insert a few RMRs (Reserved Memory Regions) in guest's IORT. Then the guest kernel would fetch these RMR entries from the IORT and create an IOMMU_RESV_DIRECT region per iommu group for a direct mapping. Eventually, the mappings would look like: IOVA (0x8000000) === IPA (0x8000000) ===> 0x20200000 This requires an IOMMUFD ioctl for kernel and VMM to agree on the IPA. 2. Forward the guest-level MSI IOVA captured by VMM to the host-level GIC driver, to program the correct MSI IOVA. Forward the VMM-defined vITS page location (IPA) to the kernel for the stage-2 mapping. Eventually: IOVA (0xFFFF0000) ===> IPA (0x80900000) ===> PA (0x20200000) This requires a VFIO ioctl (for IOVA) and an IOMMUFD ioctl (for IPA). Worth mentioning that when Eric Auger was working on the same topic with the VFIO iommu uAPI, he had the approach (2) first, and then switched to the approach (1), suggested by Jean-Philippe for reduction of complexity. The approach (1) basically feels like the existing VFIO passthrough that has a 1-stage mapping for the unmanaged domain, yet only by shifting the MSI mapping from stage 1 (guest-has-no-iommu case) to stage 2 (guest-has- iommu case). So, it could reuse the existing IOMMU_RESV_SW_MSI piece, by sharing the same idea of "VMM leaving everything to the kernel". The approach (2) is an ideal solution, yet it requires additional effort for kernel to be aware of the 1-stage gIOVA(s) and 2-stage IPAs for vITS page(s), which demands VMM to closely cooperate. * It also brings some complicated use cases to the table where the host or/and guest system(s) has/have multiple ITS pages. [ Execution ] The iommu core rework (part-1) for iommufd_sw_msi is merged. So, now the IOMMU_RESV_SW_MSI can be used as an ABI. VMM can take this hard coded MSI window and create a direct stage-1 mapping using RMR in the guest's IORT. However, a proper uAPI must be defined for kernel and VMM to agree on wrt this virtual MSI window. Moreover, some use cases might want to map the IOVAs in IOMMU_RESV_SW_MSI for something else. This requires kernel to provide an interface to shift the software MSI window to a different region: https://lore.kernel.org/all/20250909154600.910110-1-shyamsaini@linux.micros… This series, as a follow-up series, introduces a pair of iommufd options for user space to configure the software MSI window. [ Future Plan ] Part-3 and beyond will continue the effort of supporting the approach (2) for a complete vITS-to-pITS mapping: 1) Map the phsical ITS page (potentially via IOMMUFD_CMD_IOAS_MAP_MSI) 2) Convey the IOVAs per-irq (potentially via VFIO_IRQ_SET_ACTION_PREPARE) Note that the set_option uAPI in this series might not fit since this requires it is an array of MSI IOVAs.) This series is on github: https://github.com/nicolinc/iommufd/commits/iommufd_msi_p2-v2 Pairing QEMU branch for testing (approach 1): https://github.com/nicolinc/qemu/commits/wip/for_iommufd_msi_p2-v2-rmr Changelog v2 * Rebase on v6.18-rc1 * Update commit logs and kdocs * Add a patch fixing iommufd_device_is_attached() * Add sanity check for overflow and cover it in the selftest v1 (containing part-1 that is now merged) https://lore.kernel.org/all/cover.1739005085.git.nicolinc@nvidia.com/ Thanks! Nicolin Nicolin Chen (7): iommufd/device: Move sw_msi_start from igroup to idev iommufd: Pass in idev to iopt_table_enforce_dev_resv_regions iommufd/device: Make iommufd_device_is_attached non-static iommufd: Add IOMMU_OPTION_SW_MSI_START/SIZE ioctls iommufd/selftest: Add MOCK_FLAGS_DEVICE_NO_ATTACH iommufd/selftest: Add a testing reserved region iommufd/selftest: Add coverage for IOMMU_OPTION_SW_MSI_START/SIZE drivers/iommu/iommufd/iommufd_private.h | 7 +- drivers/iommu/iommufd/iommufd_test.h | 4 + include/uapi/linux/iommufd.h | 21 +++- drivers/iommu/iommufd/device.c | 43 +++---- drivers/iommu/iommufd/driver.c | 4 +- drivers/iommu/iommufd/io_pagetable.c | 18 ++- drivers/iommu/iommufd/ioas.c | 113 ++++++++++++++++++ drivers/iommu/iommufd/main.c | 4 + drivers/iommu/iommufd/selftest.c | 35 +++++- tools/testing/selftests/iommu/iommufd.c | 105 ++++++++++++++++ .../selftests/iommu/iommufd_fail_nth.c | 21 ++++ 11 files changed, 339 insertions(+), 36 deletions(-) -- 2.43.0

1 week, 2 days

2
9
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[PATCH 0/2] HID: multitouch: fix sticky-fingers quirks

by Benjamin Tissoires

According to Peter, we've had for a very long time an issue on some mutltiouch touchpads where the fingers were stuck in a scrolling mode, or 3 fingers gesture mode. I was unable to debug it because it was rather hard to reproduce. Recently, some people raised the issue again on libinput, and this time added a recording of the actual bug. It turns out that the sticky finger quirk that was introduced back in 2017 was only checking the last report, and that those missing releases also happen when moving from 3 to 1 finger (only 1 is released instead of 2). This solution seems to me to be the most sensible, because we could also add the NSMU quirk to win8 multitouch touchpads, but this would involve a lot more computations at each report for rather annoying corner cases. Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/1194 Signed-off-by: Benjamin Tissoires <bentiss(a)kernel.org> --- Benjamin Tissoires (2): HID: multitouch: fix sticky fingers selftests/hid: add tests for missing release on the Dell Synaptics drivers/hid/hid-multitouch.c | 27 ++++++----- .../testing/selftests/hid/tests/test_multitouch.py | 55 ++++++++++++++++++++++ 2 files changed, 69 insertions(+), 13 deletions(-) --- base-commit: 54ba6d9b1393a0061600c0e49c8ebef65d60a8b2 change-id: 20250926-fix-sticky-fingers-8ae88436ae82 Best regards, -- Benjamin Tissoires <bentiss(a)kernel.org>

1 week, 2 days

2
3
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[PATCH 6.1 00/15] genetlink: Test Netlink subsystem of Linux v6.1

by Yana Bashlykova

This series adds comprehensive testing infrastructure for Netlink and Generic Netlink The implementation includes both kernel module and userspace tests to verify correct Generic Netlink and Netlink behaviors under various conditions. Yana Bashlykova (15): genetlink: add sysfs test module for Generic Netlink genetlink: add TEST_GENL family for netlink testing genetlink: add PARALLEL_GENL test family genetlink: add test case for duplicate genl family registration genetlink: add test case for family with invalid ops genetlink: add netlink notifier support genetlink: add THIRD_GENL family genetlink: verify unregister fails for non-registered family genetlink: add LARGE_GENL stress test family selftests: net: genetlink: add packet capture test infrastructure selftests: net: genetlink: add /proc/net/netlink test selftests: net: genetlink: add Generic Netlink controller tests selftests: net: genetlink: add large family ID resolution test selftests: net: genetlink: add Netlink and Generic Netlink test suite selftests: net: genetlink: fix expectation for large family resolution drivers/net/Kconfig | 2 + drivers/net/Makefile | 2 + drivers/net/genetlink/Kconfig | 8 + drivers/net/genetlink/Makefile | 3 + .../net-pf-16-proto-16-family-PARALLEL_GENL.c | 1921 ++++++ tools/testing/selftests/net/Makefile | 6 + tools/testing/selftests/net/genetlink.c | 5152 +++++++++++++++++ 7 files changed, 7094 insertions(+) create mode 100644 drivers/net/genetlink/Kconfig create mode 100644 drivers/net/genetlink/Makefile create mode 100644 drivers/net/genetlink/net-pf-16-proto-16-family-PARALLEL_GENL.c create mode 100644 tools/testing/selftests/net/genetlink.c -- 2.34.1

1 week, 2 days

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[PATCH v3 0/2] selftests/fchmodat2: Error handling and general cleanups

by Mark Brown

I looked at the fchmodat2() tests since I've been experiencing some random intermittent segfaults with them in my test systems, while doing so I noticed these two issues. Unfortunately I didn't figure out the original yet, unless I managed to fix it unwittingly. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v3: - Rebase onto v6.18-rc1. - Link to v2: https://lore.kernel.org/r/20250812-selftests-fchmodat2-v2-0-f2d5380e94c3@ke… Changes in v2: - Rebase onto v6.17-rc1. - Link to v1: https://lore.kernel.org/r/20250714-selftests-fchmodat2-v1-0-b74f3ee0d09c@ke… --- Mark Brown (2): selftests/fchmodat2: Clean up temporary files and directories selftests/fchmodat2: Use ksft_finished() tools/testing/selftests/fchmodat2/fchmodat2_test.c | 166 ++++++++++++++------- 1 file changed, 112 insertions(+), 54 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20250711-selftests-fchmodat2-c30374c376f8 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 week, 2 days

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