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[PATCH net-next v5 0/8] netconsole: Add support for CPU population

by Breno Leitao

The current implementation of netconsole sends all log messages in parallel, which can lead to an intermixed and interleaved output on the receiving side. This makes it challenging to demultiplex the messages and attribute them to their originating CPUs. As a result, users and developers often struggle to effectively analyze and debug the parallel log output received through netconsole. Example of a message got from produciton hosts: ------------[ cut here ]------------ ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 2 PID: 1613668 at lib/refcount.c:22 refcount_warn_saturate+0x5e/0xe0 refcount_t: addition on 0; use-after-free. WARNING: CPU: 26 PID: 4139916 at lib/refcount.c:25 refcount_warn_saturate+0x7d/0xe0 Modules linked in: bpf_preload(E) vhost_net(E) tun(E) vhost(E) This series of patches introduces a new feature to the netconsole subsystem that allows the automatic population of the CPU number in the userdata field for each log message. This enhancement provides several benefits: * Improved demultiplexing of parallel log output: When multiple CPUs are sending messages concurrently, the added CPU number in the userdata makes it easier to differentiate and attribute the messages to their originating CPUs. * Better visibility into message sources: The CPU number information gives users and developers more insight into which specific CPU a particular log message came from, which can be valuable for debugging and analysis. The changes in this series are as follows Patches:: Patch "consolidate send buffers into netconsole_target struct" ================================================= Move the static buffers to netconsole target, from static declaration in send_msg_no_fragmentation() and send_msg_fragmented(). Patch "netconsole: Rename userdata to extradata" ================================================= Create the a concept of extradata, which encompasses the concept of userdata and the upcoming sysdatao Sysdata is a new concept being added, which is basically fields that are populated by the kernel. At this time only the CPU#, but, there is a desire to add current task name, kernel release version, etc. Patch "netconsole: Helper to count number of used entries" =========================================================== Create a simple helper to count number of entries in extradata. I am separating this in a function since it will need to count userdata and sysdata. For instance, when the user adds an extra userdata, we need to check if there is space, counting the previous data entries (from userdata and cpu data) Patch "Introduce configfs helpers for sysdata features" ====================================================== Create the concept of sysdata feature in the netconsole target, and create the configfs helpers to enable the bit in nt->sysdata Patch "Include sysdata in extradata entry count" ================================================ Add the concept of sysdata when counting for available space in the buffer. This will protect users from creating new userdata/sysdata if there is no more space Patch "netconsole: add support for sysdata and CPU population" =============================================================== This is the core patch. Basically add a new option to enable automatic CPU number population in the netconsole userdata Provides a new "cpu_nr" sysfs attribute to control this feature Patch "netconsole: selftest: test CPU number auto-population" ============================================================= Expands the existing netconsole selftest to verify the CPU number auto-population functionality Ensures the received netconsole messages contain the expected "cpu=<CPU>" entry in the message. Test different permutation with userdata Patch "netconsole: docs: Add documentation for CPU number auto-population" ============================================================================= Updates the netconsole documentation to explain the new CPU number auto-population feature Provides instructions on how to enable and use the feature I believe these changes will be a valuable addition to the netconsole subsystem, enhancing its usefulness for kernel developers and users. PS: This patchset is on top of the patch that created netcons_fragmented_msg selftest: https://lore.kernel.org/all/20250203-netcons_frag_msgs-v1-1-5bc6bedf2ac0@de… Signed-off-by: Breno Leitao <leitao(a)debian.org> --- Changes in v5: - Fixed a kernel doc syntax syntax (Simon) - Link to v4: https://lore.kernel.org/r/20250204-netcon_cpu-v4-0-9480266ef556@debian.org Changes in v4: - Fixed Kernel doc for netconsole_target (Simon) - Fixed a typo in disable_sysdata_feature (Simon) - Improved sysdata_cpu_nr_show() to return !! in a bit-wise operation - Link to v3: https://lore.kernel.org/r/20250124-netcon_cpu-v3-0-12a0d286ba1d@debian.org Changes in v3: - Moved the buffer into netconsole_target, avoiding static functions in the send path (Jakub). - Fix a documentation error (Randy Dunlap) - Created a function that handle all the extradata, consolidating it in a single place (Jakub) - Split the patch even more, trying to simplify the review. - Link to v2: https://lore.kernel.org/r/20250115-netcon_cpu-v2-0-95971b44dc56@debian.org Changes in v2: - Create the concept of extradata and sysdata. This will make the design easier to understand, and the code easier to read. * Basically extradata encompasses userdata and the new sysdata. Userdata originates from user, and sysdata originates in kernel. - Improved the test to send from a very specific CPU, which can be checked to be correct on the other side, as suggested by Jakub. - Fixed a bug where CPU # was populated at the wrong place - Link to v1: https://lore.kernel.org/r/20241113-netcon_cpu-v1-0-d187bf7c0321@debian.org --- Breno Leitao (8): netconsole: consolidate send buffers into netconsole_target struct netconsole: Rename userdata to extradata netconsole: Helper to count number of used entries netconsole: Introduce configfs helpers for sysdata features netconsole: Include sysdata in extradata entry count netconsole: add support for sysdata and CPU population netconsole: selftest: test for sysdata CPU netconsole: docs: Add documentation for CPU number auto-population Documentation/networking/netconsole.rst | 45 ++++ drivers/net/netconsole.c | 261 ++++++++++++++++----- tools/testing/selftests/drivers/net/Makefile | 1 + .../selftests/drivers/net/lib/sh/lib_netcons.sh | 17 ++ .../selftests/drivers/net/netcons_sysdata.sh | 167 +++++++++++++ 5 files changed, 427 insertions(+), 64 deletions(-) --- base-commit: 09717c28b76c30b1dc8c261c855ffb2406abab2e change-id: 20241108-netcon_cpu-ce3917e88f4b Best regards, -- Breno Leitao <leitao(a)debian.org>

7 months, 1 week

3
12
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[RFC PATCH v2 0/4] PMU partitioning driver support

by Colton Lewis

This series introduces support in the ARM PMUv3 driver for partitioning PMU counters into two separate ranges by taking advantage of the MDCR_EL2.HPMN register field. The advantage of a partitioned PMU would be to allow KVM guests direct access to a subset of PMU functionality, greatly reducing the overhead of performance monitoring in guests. While this feature could be accepted on its own merits, practically there is a lot more to be done before it will be fully useful, so I'm sending as an RFC for now. v2: * Rebase to v6.14-rc1, and take into account Oliver's debug cleanup changing some KVM handling of MDCR_EL2. * Reorder patches to put related things closer together for easier reading. * Ensure driver compiles for 32-bit ARM by defining 32-bit access to MDCR_EL2 correctly, which is called HDCR there. These will not be called due to the below requirement for VHE mode but a functionally correct definition seemed preferable to making it a no op. * Rename parameter to reserved_host_counters to better reflect underlying hardware semantics and ensure host counters are easier to preserve. * Document parameter with MODULE_PARM_DESC * Restrict partitioning to VHE mode only. Using HPMN restricts the host counters to EL2 access only. Trying to make this work for the driver running at EL1 would require hypercalls for every access of those registers and a lot of additional handling at the KVM level. This would defeat the whole purpose of having the feature at all. Define has_vhe() on 32-bit arm to always return false. * While Rob asked about making the parameter configurable at run time rather than boot time through sysfs, that is potentially very tricky because it is only safe to reprogram HPMN when we are certain no one, host or guest, is using any counters that might change ownership. If this is determined to be worthwhile, it should come after getting the core infrastructure right. * While Marc asked about reusing the sysreg masks instead of redefining them for MDCR_EL2, that doesn't work because sysreg masks are only defined for arm64. I'm not sure how to avoid the duplication. * Wrap code for determining if a counter index belongs to the host or guest partition in functions * Typo fixes and additional testing v1: https://lore.kernel.org/kvm/20250127222031.3078945-1-coltonlewis@google.com/ Colton Lewis (4): perf: arm_pmuv3: Generalize counter bitmasks perf: arm_pmuv3: Introduce module param to partition the PMU perf: arm_pmuv3: Keep out of guest counter partition KVM: arm64: Make guests see only counters they can access arch/arm/include/asm/arm_pmuv3.h | 13 ++ arch/arm64/include/asm/arm_pmuv3.h | 10 ++ arch/arm64/kvm/debug.c | 3 +- arch/arm64/kvm/pmu-emul.c | 8 +- drivers/perf/arm_pmuv3.c | 117 ++++++++++++++++-- include/linux/perf/arm_pmu.h | 2 + include/linux/perf/arm_pmuv3.h | 34 ++++- .../selftests/kvm/arm64/vpmu_counter_access.c | 2 +- 8 files changed, 168 insertions(+), 21 deletions(-) base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b -- 2.48.1.502.g6dc24dfdaf-goog

7 months, 1 week

2
8
0 0

[PATCH RFC net-next v1 0/5] Device memory TCP TX

by Mina Almasry

The TX path had been dropped from the Device Memory TCP patch series post RFCv1 [1], to make that series slightly easier to review. This series rebases the implementation of the TX path on top of the net_iov/netmem framework agreed upon and merged. The motivation for the feature is thoroughly described in the docs & cover letter of the original proposal, so I don't repeat the lengthy descriptions here, but they are available in [1]. Sending this series as RFC as the winder closure is immenient. I plan on reposting as non-RFC once the tree re-opens, addressing any feedback I receive in the meantime. Full outline on usage of the TX path is detailed in the documentation added in the first patch. Test example is available via the kselftest included in the series as well. The series is relatively small, as the TX path for this feature largely piggybacks on the existing MSG_ZEROCOPY implementation. Patch Overview: --------------- 1. Documentation & tests to give high level overview of the feature being added. 2. Add netmem refcounting needed for the TX path. 3. Devmem TX netlink API. 4. Devmem TX net stack implementation. Testing: -------- Testing is very similar to devmem TCP RX path. The ncdevmem test used for the RX path is now augemented with client functionality to test TX path. * Test Setup: Kernel: net-next with this RFC and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Performance results are not included with this version, unfortunately. I'm having issues running the dma-buf exporter driver against the upstream kernel on my test setup. The issues are specific to that dma-buf exporter and do not affect this patch series. I plan to follow up this series with perf fixes if the tests point to issues once they're up and running. Special thanks to Stan who took a stab at rebasing the TX implementation on top of the netmem/net_iov framework merged. Parts of his proposal [2] that are reused as-is are forked off into their own patches to give full credit. [1] https://lore.kernel.org/netdev/20240909054318.1809580-1-almasrymina@google.… [2] https://lore.kernel.org/netdev/20240913150913.1280238-2-sdf@fomichev.me/T/#… Cc: sdf(a)fomichev.me Cc: asml.silence(a)gmail.com Cc: dw(a)davidwei.uk Mina Almasry (4): net: add devmem TCP TX documentation selftests: ncdevmem: Implement devmem TCP TX net: add get_netmem/put_netmem support net: devmem: Implement TX path Stanislav Fomichev (1): net: devmem TCP tx netlink api Documentation/netlink/specs/netdev.yaml | 12 + Documentation/networking/devmem.rst | 140 +++++++++- include/linux/skbuff.h | 13 +- include/linux/skbuff_ref.h | 4 +- include/net/netmem.h | 3 + include/net/sock.h | 2 + include/uapi/linux/netdev.h | 1 + include/uapi/linux/uio.h | 5 + net/core/datagram.c | 40 ++- net/core/devmem.c | 101 ++++++- net/core/devmem.h | 51 +++- net/core/netdev-genl-gen.c | 13 + net/core/netdev-genl-gen.h | 1 + net/core/netdev-genl.c | 67 ++++- net/core/skbuff.c | 38 ++- net/core/sock.c | 9 + net/ipv4/tcp.c | 36 ++- net/vmw_vsock/virtio_transport_common.c | 4 +- tools/include/uapi/linux/netdev.h | 1 + .../selftests/drivers/net/hw/ncdevmem.c | 261 +++++++++++++++++- 20 files changed, 764 insertions(+), 38 deletions(-) -- 2.47.1.613.gc27f4b7a9f-goog

7 months, 1 week

5
25
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[PATCH v10 00/27] 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) In case you're building your own rootfs using toolchain, please make sure you pick following patch to ensure that vDSO compiled with lpad and shadow stack. "arch/riscv: compile vdso with landing pad" Branch where above patch can be picked https://github.com/deepak0414/linux-riscv-cfi/tree/vdso_user_cfi_v6.12-rc1 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 vDSO related Opens (in the flux) ================================= I am listing these opens for laying out plan and what to expect in future patch sets. And of course for the sake of discussion. Shadow stack and landing pad enabling in vDSO ---------------------------------------------- vDSO must have shadow stack and landing pad support compiled in for task to have shadow stack and landing pad support. This patch series doesn't enable that (yet). Enabling shadow stack support in vDSO should be straight forward (intend to do that in next versions of patch set). Enabling landing pad support in vDSO requires some collaboration with toolchain folks to follow a single label scheme for all object binaries. This is necessary to ensure that all indirect call-sites are setting correct label and target landing pads are decorated with same label scheme. How many vDSOs --------------- Shadow stack instructions are carved out of zimop (may be operations) and if CPU doesn't implement zimop, they're illegal instructions. Kernel could be running on a CPU which may or may not implement zimop. And thus kernel will have to carry 2 different vDSOs and expose the appropriate one depending on whether CPU implements zimop or not. 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/ --- changelog --------- 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. --- --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Clément Léger (1): riscv: Add Firmware Feature SBI extensions definitions Deepak Gupta (24): 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 mmu: teach pte_mkwrite to manufacture shadow stack PTEs riscv mmu: 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/traps: Introduce software check exception 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: enable kernel access to shadow stack memory via FWFT sbi call riscv: kernel command line option to opt out of user cfi 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 Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 176 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 20 + arch/riscv/Makefile | 7 +- arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 13 + 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 | 25 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 2 + arch/riscv/include/asm/sbi.h | 26 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 89 ++++ arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 22 + arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/asm-offsets.c | 8 + arch/riscv/kernel/cpufeature.c | 13 + arch/riscv/kernel/entry.S | 31 +- arch/riscv/kernel/head.S | 12 + arch/riscv/kernel/process.c | 26 +- arch/riscv/kernel/ptrace.c | 83 ++++ arch/riscv/kernel/signal.c | 142 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 43 ++ arch/riscv/kernel/usercfi.c | 524 +++++++++++++++++++++ arch/riscv/kernel/vdso/Makefile | 8 + arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 17 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 1 + 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 | 10 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 84 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 78 +++ tools/testing/selftests/riscv/cfi/shadowstack.c | 375 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 37 ++ 54 files changed, 2189 insertions(+), 29 deletions(-) --- base-commit: 39a803b754d5224a3522016b564113ee1e4091b2 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - debug

7 months, 1 week

1
27
0 0

[PATCH v5 0/2] scanf: convert self-test to KUnit

by Tamir Duberstein

This is one of just 3 remaining "Test Module" kselftests (the others being bitmap and printf), the rest having been converted to KUnit. In addition to the enclosed patch, please consider this an RFC on the removal of the "Test Module" kselftest machinery. I tested this using: $ tools/testing/kunit/kunit.py run --arch arm64 --make_options LLVM=1 scanf Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v5: - Remove extraneous trailing newlines from failure messages. - Replace `pr_debug` with `kunit_printk`. - Use static char arrays instead of kmalloc. - Drop KUnit boilerplate from CONFIG_SCANF_KUNIT_TEST help text. - Drop arch changes. - Link to v4: https://lore.kernel.org/r/20250207-scanf-kunit-convert-v4-0-a23e2afaede8@gm… Changes in v4: - Bake `test` into various macros, greatly reducing diff noise. - Revert control flow changes. - Link to v3: https://lore.kernel.org/r/20250204-scanf-kunit-convert-v3-0-386d7c3ee714@gm… Changes in v3: - Reduce diff noise in lib/Makefile. (Petr Mladek) - Split `scanf_test` into a few test cases. New output: : =================== scanf (10 subtests) ==================== : [PASSED] numbers_simple : ====================== numbers_list ======================= : [PASSED] delim=" " : [PASSED] delim=":" : [PASSED] delim="," : [PASSED] delim="-" : [PASSED] delim="/" : ================== [PASSED] numbers_list =================== : ============ numbers_list_field_width_typemax ============= : [PASSED] delim=" " : [PASSED] delim=":" : [PASSED] delim="," : [PASSED] delim="-" : [PASSED] delim="/" : ======== [PASSED] numbers_list_field_width_typemax ========= : =========== numbers_list_field_width_val_width ============ : [PASSED] delim=" " : [PASSED] delim=":" : [PASSED] delim="," : [PASSED] delim="-" : [PASSED] delim="/" : ======= [PASSED] numbers_list_field_width_val_width ======== : [PASSED] numbers_slice : [PASSED] numbers_prefix_overflow : [PASSED] test_simple_strtoull : [PASSED] test_simple_strtoll : [PASSED] test_simple_strtoul : [PASSED] test_simple_strtol : ====================== [PASSED] scanf ====================== : ============================================================ : Testing complete. Ran 22 tests: passed: 22 : Elapsed time: 5.517s total, 0.001s configuring, 5.440s building, 0.067s running - Link to v2: https://lore.kernel.org/r/20250203-scanf-kunit-convert-v2-1-277a618d804e@gm… Changes in v2: - Rename lib/{test_scanf.c => scanf_kunit.c}. (Andy Shevchenko) - Link to v1: https://lore.kernel.org/r/20250131-scanf-kunit-convert-v1-1-0976524f0eba@gm… --- Tamir Duberstein (2): scanf: convert self-test to KUnit scanf: break kunit into test cases MAINTAINERS | 2 +- lib/Kconfig.debug | 12 +- lib/Makefile | 2 +- lib/{test_scanf.c => scanf_kunit.c} | 278 ++++++++++++++++------------------- tools/testing/selftests/lib/Makefile | 2 +- tools/testing/selftests/lib/config | 1 - tools/testing/selftests/lib/scanf.sh | 4 - 7 files changed, 138 insertions(+), 163 deletions(-) --- base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3 change-id: 20250131-scanf-kunit-convert-f70dc33bb34c Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

7 months, 1 week

2
5
0 0

[PATCH v6 3/3] rseq/selftests: Add test for mm_cid compaction

by Gabriele Monaco

A task in the kernel (task_mm_cid_work) runs somewhat periodically to compact the mm_cid for each process. Add a test to validate that it runs correctly and timely. The test spawns 1 thread pinned to each CPU, then each thread, including the main one, runs in short bursts for some time. During this period, the mm_cids should be spanning all numbers between 0 and nproc. At the end of this phase, a thread with high enough mm_cid (>= nproc/2) is selected to be the new leader, all other threads terminate. After some time, the only running thread should see 0 as mm_cid, if that doesn't happen, the compaction mechanism didn't work and the test fails. The test never fails if only 1 core is available, in which case, we cannot test anything as the only available mm_cid is 0. Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Signed-off-by: Gabriele Monaco <gmonaco(a)redhat.com> --- tools/testing/selftests/rseq/.gitignore | 1 + tools/testing/selftests/rseq/Makefile | 2 +- .../selftests/rseq/mm_cid_compaction_test.c | 200 ++++++++++++++++++ 3 files changed, 202 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/rseq/mm_cid_compaction_test.c diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore index 16496de5f6ce4..2c89f97e4f737 100644 --- a/tools/testing/selftests/rseq/.gitignore +++ b/tools/testing/selftests/rseq/.gitignore @@ -3,6 +3,7 @@ basic_percpu_ops_test basic_percpu_ops_mm_cid_test basic_test basic_rseq_op_test +mm_cid_compaction_test param_test param_test_benchmark param_test_compare_twice diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile index 5a3432fceb586..ce1b38f46a355 100644 --- a/tools/testing/selftests/rseq/Makefile +++ b/tools/testing/selftests/rseq/Makefile @@ -16,7 +16,7 @@ OVERRIDE_TARGETS = 1 TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \ param_test_benchmark param_test_compare_twice param_test_mm_cid \ - param_test_mm_cid_benchmark param_test_mm_cid_compare_twice + param_test_mm_cid_benchmark param_test_mm_cid_compare_twice mm_cid_compaction_test TEST_GEN_PROGS_EXTENDED = librseq.so diff --git a/tools/testing/selftests/rseq/mm_cid_compaction_test.c b/tools/testing/selftests/rseq/mm_cid_compaction_test.c new file mode 100644 index 0000000000000..7ddde3b657dd6 --- /dev/null +++ b/tools/testing/selftests/rseq/mm_cid_compaction_test.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: LGPL-2.1 +#define _GNU_SOURCE +#include <assert.h> +#include <pthread.h> +#include <sched.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <stddef.h> + +#include "../kselftest.h" +#include "rseq.h" + +#define VERBOSE 0 +#define printf_verbose(fmt, ...) \ + do { \ + if (VERBOSE) \ + printf(fmt, ##__VA_ARGS__); \ + } while (0) + +/* 0.5 s */ +#define RUNNER_PERIOD 500000 +/* Number of runs before we terminate or get the token */ +#define THREAD_RUNS 5 + +/* + * Number of times we check that the mm_cid were compacted. + * Checks are repeated every RUNNER_PERIOD. + */ +#define MM_CID_COMPACT_TIMEOUT 10 + +struct thread_args { + int cpu; + int num_cpus; + pthread_mutex_t *token; + pthread_barrier_t *barrier; + pthread_t *tinfo; + struct thread_args *args_head; +}; + +static void __noreturn *thread_runner(void *arg) +{ + struct thread_args *args = arg; + int i, ret, curr_mm_cid; + cpu_set_t cpumask; + + CPU_ZERO(&cpumask); + CPU_SET(args->cpu, &cpumask); + ret = pthread_setaffinity_np(pthread_self(), sizeof(cpumask), &cpumask); + if (ret) { + errno = ret; + perror("Error: failed to set affinity"); + abort(); + } + pthread_barrier_wait(args->barrier); + + for (i = 0; i < THREAD_RUNS; i++) + usleep(RUNNER_PERIOD); + curr_mm_cid = rseq_current_mm_cid(); + /* + * We select one thread with high enough mm_cid to be the new leader. + * All other threads (including the main thread) will terminate. + * After some time, the mm_cid of the only remaining thread should + * converge to 0, if not, the test fails. + */ + if (curr_mm_cid >= args->num_cpus / 2 && + !pthread_mutex_trylock(args->token)) { + printf_verbose( + "cpu%d has mm_cid=%d and will be the new leader.\n", + sched_getcpu(), curr_mm_cid); + for (i = 0; i < args->num_cpus; i++) { + if (args->tinfo[i] == pthread_self()) + continue; + ret = pthread_join(args->tinfo[i], NULL); + if (ret) { + errno = ret; + perror("Error: failed to join thread"); + abort(); + } + } + pthread_barrier_destroy(args->barrier); + free(args->tinfo); + free(args->token); + free(args->barrier); + free(args->args_head); + + for (i = 0; i < MM_CID_COMPACT_TIMEOUT; i++) { + curr_mm_cid = rseq_current_mm_cid(); + printf_verbose("run %d: mm_cid=%d on cpu%d.\n", i, + curr_mm_cid, sched_getcpu()); + if (curr_mm_cid == 0) + exit(EXIT_SUCCESS); + usleep(RUNNER_PERIOD); + } + exit(EXIT_FAILURE); + } + printf_verbose("cpu%d has mm_cid=%d and is going to terminate.\n", + sched_getcpu(), curr_mm_cid); + pthread_exit(NULL); +} + +int test_mm_cid_compaction(void) +{ + cpu_set_t affinity; + int i, j, ret = 0, num_threads; + pthread_t *tinfo; + pthread_mutex_t *token; + pthread_barrier_t *barrier; + struct thread_args *args; + + sched_getaffinity(0, sizeof(affinity), &affinity); + num_threads = CPU_COUNT(&affinity); + tinfo = calloc(num_threads, sizeof(*tinfo)); + if (!tinfo) { + perror("Error: failed to allocate tinfo"); + return -1; + } + args = calloc(num_threads, sizeof(*args)); + if (!args) { + perror("Error: failed to allocate args"); + ret = -1; + goto out_free_tinfo; + } + token = malloc(sizeof(*token)); + if (!token) { + perror("Error: failed to allocate token"); + ret = -1; + goto out_free_args; + } + barrier = malloc(sizeof(*barrier)); + if (!barrier) { + perror("Error: failed to allocate barrier"); + ret = -1; + goto out_free_token; + } + if (num_threads == 1) { + fprintf(stderr, "Cannot test on a single cpu. " + "Skipping mm_cid_compaction test.\n"); + /* only skipping the test, this is not a failure */ + goto out_free_barrier; + } + pthread_mutex_init(token, NULL); + ret = pthread_barrier_init(barrier, NULL, num_threads); + if (ret) { + errno = ret; + perror("Error: failed to initialise barrier"); + goto out_free_barrier; + } + for (i = 0, j = 0; i < CPU_SETSIZE && j < num_threads; i++) { + if (!CPU_ISSET(i, &affinity)) + continue; + args[j].num_cpus = num_threads; + args[j].tinfo = tinfo; + args[j].token = token; + args[j].barrier = barrier; + args[j].cpu = i; + args[j].args_head = args; + if (!j) { + /* The first thread is the main one */ + tinfo[0] = pthread_self(); + ++j; + continue; + } + ret = pthread_create(&tinfo[j], NULL, thread_runner, &args[j]); + if (ret) { + errno = ret; + perror("Error: failed to create thread"); + abort(); + } + ++j; + } + printf_verbose("Started %d threads.\n", num_threads); + + /* Also main thread will terminate if it is not selected as leader */ + thread_runner(&args[0]); + + /* only reached in case of errors */ +out_free_barrier: + free(barrier); +out_free_token: + free(token); +out_free_args: + free(args); +out_free_tinfo: + free(tinfo); + + return ret; +} + +int main(int argc, char **argv) +{ + if (!rseq_mm_cid_available()) { + fprintf(stderr, "Error: rseq_mm_cid unavailable\n"); + return -1; + } + if (test_mm_cid_compaction()) + return -1; + return 0; +} -- 2.48.1

7 months, 1 week

1
0
0 0

[PATCH v2 0/2] printf: convert self-test to KUnit

by Tamir Duberstein

This is one of just 3 remaining "Test Module" kselftests (the others being bitmap and scanf), the rest having been converted to KUnit. I tested this using: $ tools/testing/kunit/kunit.py run --arch arm64 --make_options LLVM=1 printf I have also sent out a series converting scanf[0]. Link: https://lore.kernel.org/all/20250204-scanf-kunit-convert-v3-0-386d7c3ee714@… [0] Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v2: - Incorporate code review from prior work[0] by Arpitha Raghunandan. - Link to v1: https://lore.kernel.org/r/20250204-printf-kunit-convert-v1-0-ecf1b846a4de@g… Link: https://lore.kernel.org/lkml/20200817043028.76502-1-98.arpi@gmail.com/t/#u [0] --- Tamir Duberstein (2): printf: convert self-test to KUnit printf: break kunit into test cases Documentation/core-api/printk-formats.rst | 2 +- MAINTAINERS | 2 +- arch/m68k/configs/amiga_defconfig | 1 - arch/m68k/configs/apollo_defconfig | 1 - arch/m68k/configs/atari_defconfig | 1 - arch/m68k/configs/bvme6000_defconfig | 1 - arch/m68k/configs/hp300_defconfig | 1 - arch/m68k/configs/mac_defconfig | 1 - arch/m68k/configs/multi_defconfig | 1 - arch/m68k/configs/mvme147_defconfig | 1 - arch/m68k/configs/mvme16x_defconfig | 1 - arch/m68k/configs/q40_defconfig | 1 - arch/m68k/configs/sun3_defconfig | 1 - arch/m68k/configs/sun3x_defconfig | 1 - arch/powerpc/configs/ppc64_defconfig | 1 - lib/Kconfig.debug | 20 +- lib/Makefile | 2 +- lib/{test_printf.c => printf_kunit.c} | 400 ++++++++++++------------------ tools/testing/selftests/lib/config | 1 - tools/testing/selftests/lib/printf.sh | 4 - 20 files changed, 182 insertions(+), 262 deletions(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20250131-printf-kunit-convert-fd4012aa2ec6 Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

7 months, 1 week

3
7
0 0

[PATCH v5 0/7] ptrace: introduce PTRACE_SET_SYSCALL_INFO API

by Dmitry V. Levin

PTRACE_SET_SYSCALL_INFO is a generic ptrace API that complements PTRACE_GET_SYSCALL_INFO by letting the ptracer modify details of system calls the tracee is blocked in. This API allows ptracers to obtain and modify system call details in a straightforward and architecture-agnostic way, providing a consistent way of manipulating the system call number and arguments across architectures. As in case of PTRACE_GET_SYSCALL_INFO, PTRACE_SET_SYSCALL_INFO also does not aim to address numerous architecture-specific system call ABI peculiarities, like differences in the number of system call arguments for such system calls as pread64 and preadv. The current implementation supports changing only those bits of system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. Support of changing additional details returned by PTRACE_GET_SYSCALL_INFO, such as instruction pointer and stack pointer, could be added later if needed, by using struct ptrace_syscall_info.flags to specify the additional details that should be set. Currently, "flags" and "reserved" fields of struct ptrace_syscall_info must be initialized with zeroes; "arch", "instruction_pointer", and "stack_pointer" fields are currently ignored. PTRACE_SET_SYSCALL_INFO currently supports only PTRACE_SYSCALL_INFO_ENTRY, PTRACE_SYSCALL_INFO_EXIT, and PTRACE_SYSCALL_INFO_SECCOMP operations. Other operations could be added later if needed. Ideally, PTRACE_SET_SYSCALL_INFO should have been introduced along with PTRACE_GET_SYSCALL_INFO, but it didn't happen. The last straw that convinced me to implement PTRACE_SET_SYSCALL_INFO was apparent failure to provide an API of changing the first system call argument on riscv architecture [1]. ptrace(2) man page: long ptrace(enum __ptrace_request request, pid_t pid, void *addr, void *data); ... PTRACE_SET_SYSCALL_INFO Modify information about the system call that caused the stop. The "data" argument is a pointer to struct ptrace_syscall_info that specifies the system call information to be set. The "addr" argument should be set to sizeof(struct ptrace_syscall_info)). [1] https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@gmail.com/ Notes: v5: * ptrace: Extend the commit message to say that the new API does not aim to address numerous architecture-specific syscall ABI peculiarities * selftests: Add a workaround for s390 16-bit syscall numbers * Add more Acked-by * v4: https://lore.kernel.org/all/20250203065849.GA14120@strace.io/ v4: * Split out syscall_set_return_value() for hexagon into a separate patch * s390: Change the style of syscall_set_arguments() implementation as requested * Add more Reviewed-by * v3: https://lore.kernel.org/all/20250128091445.GA8257@strace.io/ v3: * powerpc: Submit syscall_set_return_value() fix for "sc" case separately * mips: Do not introduce erroneous argument truncation on mips n32, add a detailed description to the commit message of the mips_get_syscall_arg() change * ptrace: Add explicit padding to the end of struct ptrace_syscall_info, simplify obtaining of user ptrace_syscall_info, do not introduce PTRACE_SYSCALL_INFO_SIZE_VER0 * ptrace: Change the return type of ptrace_set_syscall_info_* functions from "unsigned long" to "int" * ptrace: Add -ERANGE check to ptrace_set_syscall_info_exit(), add comments to -ERANGE checks * ptrace: Update comments about supported syscall stops * selftests: Extend set_syscall_info test, fix for mips n32 * Add Tested-by and Reviewed-by v2: * Add patch to fix syscall_set_return_value() on powerpc * Add patch to fix mips_get_syscall_arg() on mips * Add syscall_set_return_value() implementation on hexagon * Add syscall_set_return_value() invocation to syscall_set_nr() on arm and arm64. * Fix syscall_set_nr() and mips_set_syscall_arg() on mips * Add a comment to syscall_set_nr() on arc, powerpc, s390, sh, and sparc * Remove redundant ptrace_syscall_info.op assignments in ptrace_get_syscall_info_* * Minor style tweaks in ptrace_get_syscall_info_op() * Remove syscall_set_return_value() invocation from ptrace_set_syscall_info_entry() * Skip syscall_set_arguments() invocation in case of syscall number -1 in ptrace_set_syscall_info_entry() * Split ptrace_syscall_info.reserved into ptrace_syscall_info.reserved and ptrace_syscall_info.flags * Use __kernel_ulong_t instead of unsigned long in set_syscall_info test Dmitry V. Levin (7): mips: fix mips_get_syscall_arg() for o32 hexagon: add syscall_set_return_value() syscall.h: add syscall_set_arguments() syscall.h: introduce syscall_set_nr() ptrace_get_syscall_info: factor out ptrace_get_syscall_info_op ptrace: introduce PTRACE_SET_SYSCALL_INFO request selftests/ptrace: add a test case for PTRACE_SET_SYSCALL_INFO arch/arc/include/asm/syscall.h | 25 + arch/arm/include/asm/syscall.h | 37 ++ arch/arm64/include/asm/syscall.h | 29 + arch/csky/include/asm/syscall.h | 13 + arch/hexagon/include/asm/syscall.h | 21 + arch/loongarch/include/asm/syscall.h | 15 + arch/m68k/include/asm/syscall.h | 7 + arch/microblaze/include/asm/syscall.h | 7 + arch/mips/include/asm/syscall.h | 70 ++- arch/nios2/include/asm/syscall.h | 16 + arch/openrisc/include/asm/syscall.h | 13 + arch/parisc/include/asm/syscall.h | 19 + arch/powerpc/include/asm/syscall.h | 20 + arch/riscv/include/asm/syscall.h | 16 + arch/s390/include/asm/syscall.h | 21 + arch/sh/include/asm/syscall_32.h | 24 + arch/sparc/include/asm/syscall.h | 22 + arch/um/include/asm/syscall-generic.h | 19 + arch/x86/include/asm/syscall.h | 43 ++ arch/xtensa/include/asm/syscall.h | 18 + include/asm-generic/syscall.h | 30 + include/uapi/linux/ptrace.h | 7 +- kernel/ptrace.c | 179 +++++- tools/testing/selftests/ptrace/Makefile | 2 +- .../selftests/ptrace/set_syscall_info.c | 519 ++++++++++++++++++ 25 files changed, 1145 insertions(+), 47 deletions(-) create mode 100644 tools/testing/selftests/ptrace/set_syscall_info.c -- ldv

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[PATCH v9 00/26] 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) In case you're building your own rootfs using toolchain, please make sure you pick following patch to ensure that vDSO compiled with lpad and shadow stack. "arch/riscv: compile vdso with landing pad" Branch where above patch can be picked https://github.com/deepak0414/linux-riscv-cfi/tree/vdso_user_cfi_v6.12-rc1 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 vDSO related Opens (in the flux) ================================= I am listing these opens for laying out plan and what to expect in future patch sets. And of course for the sake of discussion. Shadow stack and landing pad enabling in vDSO ---------------------------------------------- vDSO must have shadow stack and landing pad support compiled in for task to have shadow stack and landing pad support. This patch series doesn't enable that (yet). Enabling shadow stack support in vDSO should be straight forward (intend to do that in next versions of patch set). Enabling landing pad support in vDSO requires some collaboration with toolchain folks to follow a single label scheme for all object binaries. This is necessary to ensure that all indirect call-sites are setting correct label and target landing pads are decorated with same label scheme. How many vDSOs --------------- Shadow stack instructions are carved out of zimop (may be operations) and if CPU doesn't implement zimop, they're illegal instructions. Kernel could be running on a CPU which may or may not implement zimop. And thus kernel will have to carry 2 different vDSOs and expose the appropriate one depending on whether CPU implements zimop or not. 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/ --- changelog --------- 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 v9: - EDITME: describe what is new in this series revision. - EDITME: use bulletpoints and terse descriptions. - Link to v8: https://lore.kernel.org/r/20241111-v5_user_cfi_series-v8-0-dce14aa30207@riv… Changes in v8: - EDITME: describe what is new in this series revision. - EDITME: use bulletpoints and terse descriptions. - Link to v7: https://lore.kernel.org/r/20241029-v5_user_cfi_series-v7-0-2727ce9936cb@riv… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Clément Léger (1): riscv: Add Firmware Feature SBI extensions definitions Deepak Gupta (24): mm: helper `is_shadow_stack_vma` to check shadow stack vma 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 mmu: teach pte_mkwrite to manufacture shadow stack PTEs riscv mmu: 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/traps: Introduce software check exception 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: enable kernel access to shadow stack memory via FWFT sbi call riscv: kernel command line option to opt out of user cfi 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 Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 176 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 20 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/cpufeature.h | 13 + 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 | 25 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 2 + arch/riscv/include/asm/sbi.h | 26 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 89 ++++ arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 22 + arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/asm-offsets.c | 8 + arch/riscv/kernel/cpufeature.c | 2 + arch/riscv/kernel/entry.S | 31 +- arch/riscv/kernel/head.S | 12 + arch/riscv/kernel/process.c | 26 +- arch/riscv/kernel/ptrace.c | 83 ++++ arch/riscv/kernel/signal.c | 142 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 43 ++ arch/riscv/kernel/usercfi.c | 524 +++++++++++++++++++++ arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 17 + include/linux/cpu.h | 4 + include/uapi/linux/elf.h | 1 + include/uapi/linux/prctl.h | 27 ++ kernel/sys.c | 30 ++ mm/gup.c | 2 +- mm/mmap.c | 2 +- mm/vma.h | 10 +- tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 10 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 84 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 78 +++ tools/testing/selftests/riscv/cfi/shadowstack.c | 375 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 37 ++ 49 files changed, 2106 insertions(+), 33 deletions(-) --- base-commit: 39a803b754d5224a3522016b564113ee1e4091b2 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - debug

7 months, 1 week

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Re: [PATCH 0/6] KUnit test moves / renames

by Stephen Rothwell

Hi all, On Mon, 10 Feb 2025 04:43:28 +0530 Shuah Khan <skhan(a)linuxfoundation.org> wrote: > > On Sun, Feb 9, 2025, 2:44 AM Kees Cook <kees(a)kernel.org> wrote: > > > On Fri, Oct 11, 2024 at 07:53:43AM -0600, Shuah Khan wrote: > > > On 10/11/24 01:25, David Gow wrote: > > > > As discussed in [1], the KUnit test naming scheme has changed to avoid > > > > name conflicts (and tab-completion woes) with the files being tested. > > > > These renames and moves have caused a nasty set of merge conflicts, so > > > > this series collates and rebases them all to be applied via > > > > mm-nonmm-unstable alongside any lib/ changes[2]. > > > > Shall I carry this in the hardening tree? I didn't see it land in the > > merge window, and I still don't see it in -next? > > > > My thinking was that this series would go through Andrew's tree to avoid > conflicts. Please take it through yours. If they have been rebased onto mm-nonmm-unstable, then they really need to go through Andrew' tree (since mm-nonmm-unstable gets rebased often). -- Cheers, Stephen Rothwell

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