From: Mark Brown <broonie@kernel.org> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>, Andrew Morton <akpm@linux-foundation.org>, Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, James Morse <james.morse@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>, Eric Biederman <ebiederm@xmission.com>, Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>, "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>, Deepak Gupta <debug@rivosinc.com>, Ard Biesheuvel <ardb@kernel.org>, Szabolcs Nagy <Szabolcs.Nagy@arm.com> Cc: "H.J. Lu" <hjl.tools@gmail.com>, Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown <broonie@kernel.org> Subject: [PATCH v2 01/35] prctl: arch-agnostic prctl for shadow stack Date: Mon, 24 Jul 2023 13:45:48 +0100 [thread overview] Message-ID: <20230724-arm64-gcs-v2-1-dc2c1d44c2eb@kernel.org> (raw) In-Reply-To: <20230724-arm64-gcs-v2-0-dc2c1d44c2eb@kernel.org> Three architectures (x86, aarch64, riscv) have announced support for shadow stacks with fairly similar functionality. While x86 is using arch_prctl() to control the functionality neither arm64 nor riscv uses that interface so this patch adds arch-agnostic prctl() support to get and set status of shadow stacks and lock the current configuation to prevent further changes, with support for turning on and off individual subfeatures so applications can limit their exposure to features that they do not need. The features are: - PR_SHADOW_STACK_ENABLE: Tracking and enforcement of shadow stacks, including allocation of a shadow stack if one is not already allocated. - PR_SHADOW_STACK_WRITE: Writes to specific addresses in the shadow stack. - PR_SHADOW_STACK_PUSH: Push additional values onto the shadow stack. These features are expected to be inherited by new threads and cleared on exec(), unknown features should be rejected for enable but accepted for locking (in order to allow for future proofing). This is based on a patch originally written by Deepak Gupta but modified fairly heavily, support for indirect landing pads is removed, additional modes added and the locking interface reworked. The set status prctl() is also reworked to just set flags, if setting/reading the shadow stack pointer is required this could be a separate prctl. Signed-off-by: Mark Brown <broonie@kernel.org> --- include/linux/mm.h | 4 ++++ include/uapi/linux/prctl.h | 22 ++++++++++++++++++++++ kernel/sys.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 56 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 97eddc83d19c..c57c5030ef6c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3947,4 +3947,8 @@ static inline void accept_memory(phys_addr_t start, phys_addr_t end) #endif +int arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status); +int arch_set_shadow_stack_status(struct task_struct *t, unsigned long status); +int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status); + #endif /* _LINUX_MM_H */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 3c36aeade991..0de3d6ee18e0 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -305,4 +305,26 @@ struct prctl_mm_map { # define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc # define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f +/* + * Get the current shadow stack configuration for the current thread, + * this will be the value configured via PR_SET_SHADOW_STACK_STATUS. + */ +#define PR_GET_SHADOW_STACK_STATUS 71 + +/* + * Set the current shadow stack configuration. Enabling the shadow + * stack will cause a shadow stack to be allocated for the thread. + */ +#define PR_SET_SHADOW_STACK_STATUS 72 +# define PR_SHADOW_STACK_ENABLE (1UL << 0) +# define PR_SHADOW_STACK_WRITE (1UL << 1) +# define PR_SHADOW_STACK_PUSH (1UL << 2) + +/* + * Prevent further changes to the specified shadow stack + * configuration. All bits may be locked via this call, including + * undefined bits. + */ +#define PR_LOCK_SHADOW_STACK_STATUS 73 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 2410e3999ebe..b26423a614a9 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2302,6 +2302,21 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, return -EINVAL; } +int __weak arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status) +{ + return -EINVAL; +} + +int __weak arch_set_shadow_stack_status(struct task_struct *t, unsigned long status) +{ + return -EINVAL; +} + +int __weak arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status) +{ + return -EINVAL; +} + #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) #ifdef CONFIG_ANON_VMA_NAME @@ -2720,6 +2735,21 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_RISCV_V_GET_CONTROL: error = RISCV_V_GET_CONTROL(); break; + case PR_GET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_get_shadow_stack_status(me, (unsigned long __user *) arg2); + break; + case PR_SET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_set_shadow_stack_status(me, arg2); + break; + case PR_LOCK_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_lock_shadow_stack_status(me, arg2); + break; default: error = -EINVAL; break; -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Mark Brown <broonie@kernel.org> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>, Andrew Morton <akpm@linux-foundation.org>, Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, James Morse <james.morse@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>, Eric Biederman <ebiederm@xmission.com>, Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>, "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>, Deepak Gupta <debug@rivosinc.com>, Ard Biesheuvel <ardb@kernel.org>, Szabolcs Nagy <Szabolcs.Nagy@arm.com> Cc: "H.J. Lu" <hjl.tools@gmail.com>, Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown <broonie@kernel.org> Subject: [PATCH v2 01/35] prctl: arch-agnostic prctl for shadow stack Date: Mon, 24 Jul 2023 13:45:48 +0100 [thread overview] Message-ID: <20230724-arm64-gcs-v2-1-dc2c1d44c2eb@kernel.org> (raw) In-Reply-To: <20230724-arm64-gcs-v2-0-dc2c1d44c2eb@kernel.org> Three architectures (x86, aarch64, riscv) have announced support for shadow stacks with fairly similar functionality. While x86 is using arch_prctl() to control the functionality neither arm64 nor riscv uses that interface so this patch adds arch-agnostic prctl() support to get and set status of shadow stacks and lock the current configuation to prevent further changes, with support for turning on and off individual subfeatures so applications can limit their exposure to features that they do not need. The features are: - PR_SHADOW_STACK_ENABLE: Tracking and enforcement of shadow stacks, including allocation of a shadow stack if one is not already allocated. - PR_SHADOW_STACK_WRITE: Writes to specific addresses in the shadow stack. - PR_SHADOW_STACK_PUSH: Push additional values onto the shadow stack. These features are expected to be inherited by new threads and cleared on exec(), unknown features should be rejected for enable but accepted for locking (in order to allow for future proofing). This is based on a patch originally written by Deepak Gupta but modified fairly heavily, support for indirect landing pads is removed, additional modes added and the locking interface reworked. The set status prctl() is also reworked to just set flags, if setting/reading the shadow stack pointer is required this could be a separate prctl. Signed-off-by: Mark Brown <broonie@kernel.org> --- include/linux/mm.h | 4 ++++ include/uapi/linux/prctl.h | 22 ++++++++++++++++++++++ kernel/sys.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 56 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 97eddc83d19c..c57c5030ef6c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3947,4 +3947,8 @@ static inline void accept_memory(phys_addr_t start, phys_addr_t end) #endif +int arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status); +int arch_set_shadow_stack_status(struct task_struct *t, unsigned long status); +int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status); + #endif /* _LINUX_MM_H */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 3c36aeade991..0de3d6ee18e0 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -305,4 +305,26 @@ struct prctl_mm_map { # define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc # define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f +/* + * Get the current shadow stack configuration for the current thread, + * this will be the value configured via PR_SET_SHADOW_STACK_STATUS. + */ +#define PR_GET_SHADOW_STACK_STATUS 71 + +/* + * Set the current shadow stack configuration. Enabling the shadow + * stack will cause a shadow stack to be allocated for the thread. + */ +#define PR_SET_SHADOW_STACK_STATUS 72 +# define PR_SHADOW_STACK_ENABLE (1UL << 0) +# define PR_SHADOW_STACK_WRITE (1UL << 1) +# define PR_SHADOW_STACK_PUSH (1UL << 2) + +/* + * Prevent further changes to the specified shadow stack + * configuration. All bits may be locked via this call, including + * undefined bits. + */ +#define PR_LOCK_SHADOW_STACK_STATUS 73 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 2410e3999ebe..b26423a614a9 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2302,6 +2302,21 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, return -EINVAL; } +int __weak arch_get_shadow_stack_status(struct task_struct *t, unsigned long __user *status) +{ + return -EINVAL; +} + +int __weak arch_set_shadow_stack_status(struct task_struct *t, unsigned long status) +{ + return -EINVAL; +} + +int __weak arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status) +{ + return -EINVAL; +} + #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) #ifdef CONFIG_ANON_VMA_NAME @@ -2720,6 +2735,21 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_RISCV_V_GET_CONTROL: error = RISCV_V_GET_CONTROL(); break; + case PR_GET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_get_shadow_stack_status(me, (unsigned long __user *) arg2); + break; + case PR_SET_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_set_shadow_stack_status(me, arg2); + break; + case PR_LOCK_SHADOW_STACK_STATUS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = arch_lock_shadow_stack_status(me, arg2); + break; default: error = -EINVAL; break; -- 2.30.2 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2023-07-24 12:47 UTC|newest] Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-24 12:45 [PATCH v2 00/35] arm64/gcs: Provide support for GCS in userspace Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` Mark Brown [this message] 2023-07-24 12:45 ` [PATCH v2 01/35] prctl: arch-agnostic prctl for shadow stack Mark Brown 2023-07-24 12:45 ` [PATCH v2 02/35] arm64: Document boot requirements for Guarded Control Stacks Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 03/35] arm64/gcs: Document the ABI " Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 04/35] arm64/sysreg: Add new system registers for GCS Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 05/35] arm64/sysreg: Add definitions for architected GCS caps Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 06/35] arm64/gcs: Add manual encodings of GCS instructions Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 07/35] arm64/gcs: Provide copy_to_user_gcs() Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 08/35] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 09/35] arm64/mm: Allocate PIE slots for EL0 guarded control stack Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 10/35] mm: Define VM_SHADOW_STACK for arm64 when we support GCS Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 11/35] arm64/mm: Map pages for guarded control stack Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:45 ` [PATCH v2 12/35] KVM: arm64: Manage GCS registers for guests Mark Brown 2023-07-24 12:45 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 13/35] arm64/el2_setup: Allow GCS usage at EL0 and EL1 Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 14/35] arm64/idreg: Add overrride for GCS Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 15/35] arm64/hwcap: Add hwcap " Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 16/35] arm64/traps: Handle GCS exceptions Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 17/35] arm64/mm: Handle GCS data aborts Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 18/35] arm64/gcs: Context switch GCS registers for EL0 Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 19/35] arm64/gcs: Allocate a new GCS for threads with GCS enabled Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 20/35] arm64/gcs: Implement shadow stack prctl() interface Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 21/35] arm64/mm: Implement map_shadow_stack() Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 22/35] arm64/signal: Set up and restore the GCS context for signal handlers Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 23/35] arm64/signal: Expose GCS state in signal frames Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 24/35] arm64/ptrace: Expose GCS via ptrace and core files Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 25/35] arm64: Add Kconfig for Guarded Control Stack (GCS) Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 26/35] kselftest/arm64: Verify the GCS hwcap Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 27/35] kselftest/arm64: Add GCS as a detected feature in the signal tests Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 28/35] kselftest/arm64: Add framework support for GCS to signal handling tests Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 29/35] kselftest/arm64: Allow signals tests to specify an expected si_code Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 30/35] kselftest/arm64: Always run signals tests with GCS enabled Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 31/35] kselftest/arm64: Add very basic GCS test program Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 32/35] kselftest/arm64: Add a GCS test program built with the system libc Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 33/35] kselftest/arm64: Add test coverage for GCS mode locking Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 34/35] selftests/arm64: Add GCS signal tests Mark Brown 2023-07-24 12:46 ` Mark Brown 2023-07-24 12:46 ` [PATCH v2 35/35] kselftest/arm64: Enable GCS for the FP stress tests Mark Brown 2023-07-24 12:46 ` Mark Brown
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