From: Andrey Konovalov <andreyknvl@google.com> To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Will Deacon <will.deacon@arm.com>, Mark Rutland <mark.rutland@arm.com>, Andrew Morton <akpm@linux-foundation.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Kees Cook <keescook@chromium.org>, Yishai Hadas <yishaih@mellanox.com>, Felix Kuehling <Felix.Kuehling@amd.com>, Alexander Deucher <Alexander.Deucher@amd.com>, Christian Koenig <Christian.Koenig@amd.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, Jens Wiklander <jens.wiklander@linaro.org>, Alex Williamson <alex.williamson@redhat.com>, Leon Romanovsky <leon@kernel.org>, Luc Van Oostenryck <luc.vanoostenryck@gmail.com>, Dave Martin <Dave.Martin@arm.com>, Khalid Aziz <khalid.aziz@oracle.com>, enh <enh@google.com>, Jason Gunthorpe <jgg@ziepe.ca>, Christoph Hellwig <hch@infradead.org>, Dmitry Vyukov <dvyukov@google.com>, Kostya Serebryany <kcc@google.com>, Evgeniy Stepanov <eugenis@google.com>, Lee Smith <Lee.Smith@arm.com>, Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>, Jacob Bramley <Jacob.Bramley@arm.com>, Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>, Robin Murphy <robin.murphy@arm.com>, Kevin Brodsky <kevin.brodsky@arm.com>, Szabolcs Nagy <Szabolcs.Nagy@arm.com> Subject: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Date: Wed, 12 Jun 2019 13:43:20 +0200 Message-ID: <a7a2933bea5fe57e504891b7eec7e9432e5e1c1a.1560339705.git.andreyknvl@google.com> (raw) In-Reply-To: <cover.1560339705.git.andreyknvl@google.com> From: Catalin Marinas <catalin.marinas@arm.com> It is not desirable to relax the ABI to allow tagged user addresses into the kernel indiscriminately. This patch introduces a prctl() interface for enabling or disabling the tagged ABI with a global sysctl control for preventing applications from enabling the relaxed ABI (meant for testing user-space prctl() return error checking without reconfiguring the kernel). The ABI properties are inherited by threads of the same application and fork()'ed children but cleared on execve(). The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle MTE-specific settings like imprecise vs precise exceptions. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> --- arch/arm64/include/asm/processor.h | 6 +++ arch/arm64/include/asm/thread_info.h | 1 + arch/arm64/include/asm/uaccess.h | 3 +- arch/arm64/kernel/process.c | 67 ++++++++++++++++++++++++++++ include/uapi/linux/prctl.h | 5 +++ kernel/sys.c | 16 +++++++ 6 files changed, 97 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index fcd0e691b1ea..fee457456aa8 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void); /* PR_PAC_RESET_KEYS prctl */ #define PAC_RESET_KEYS(tsk, arg) ptrauth_prctl_reset_keys(tsk, arg) +/* PR_TAGGED_ADDR prctl */ +long set_tagged_addr_ctrl(unsigned long arg); +long get_tagged_addr_ctrl(void); +#define SET_TAGGED_ADDR_CTRL(arg) set_tagged_addr_ctrl(arg) +#define GET_TAGGED_ADDR_CTRL() get_tagged_addr_ctrl() + /* * For CONFIG_GCC_PLUGIN_STACKLEAK * diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index f1d032be628a..354a31d2b737 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -99,6 +99,7 @@ void arch_release_task_struct(struct task_struct *tsk); #define TIF_SVE 23 /* Scalable Vector Extension in use */ #define TIF_SVE_VL_INHERIT 24 /* Inherit sve_vl_onexec across exec */ #define TIF_SSBD 25 /* Wants SSB mitigation */ +#define TIF_TAGGED_ADDR 26 /* Allow tagged user addresses */ #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index df729afca0ba..995b9ea11a89 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -73,7 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si { unsigned long ret, limit = current_thread_info()->addr_limit; - addr = untagged_addr(addr); + if (test_thread_flag(TIF_TAGGED_ADDR)) + addr = untagged_addr(addr); __chk_user_ptr(addr); asm volatile( diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 3767fb21a5b8..69d0be1fc708 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -30,6 +30,7 @@ #include <linux/kernel.h> #include <linux/mm.h> #include <linux/stddef.h> +#include <linux/sysctl.h> #include <linux/unistd.h> #include <linux/user.h> #include <linux/delay.h> @@ -323,6 +324,7 @@ void flush_thread(void) fpsimd_flush_thread(); tls_thread_flush(); flush_ptrace_hw_breakpoint(current); + clear_thread_flag(TIF_TAGGED_ADDR); } void release_thread(struct task_struct *dead_task) @@ -552,3 +554,68 @@ void arch_setup_new_exec(void) ptrauth_thread_init_user(current); } + +/* + * Control the relaxed ABI allowing tagged user addresses into the kernel. + */ +static unsigned int tagged_addr_prctl_allowed = 1; + +long set_tagged_addr_ctrl(unsigned long arg) +{ + if (!tagged_addr_prctl_allowed) + return -EINVAL; + if (is_compat_task()) + return -EINVAL; + if (arg & ~PR_TAGGED_ADDR_ENABLE) + return -EINVAL; + + if (arg & PR_TAGGED_ADDR_ENABLE) + set_thread_flag(TIF_TAGGED_ADDR); + else + clear_thread_flag(TIF_TAGGED_ADDR); + + return 0; +} + +long get_tagged_addr_ctrl(void) +{ + if (!tagged_addr_prctl_allowed) + return -EINVAL; + if (is_compat_task()) + return -EINVAL; + + if (test_thread_flag(TIF_TAGGED_ADDR)) + return PR_TAGGED_ADDR_ENABLE; + + return 0; +} + +/* + * Global sysctl to disable the tagged user addresses support. This control + * only prevents the tagged address ABI enabling via prctl() and does not + * disable it for tasks that already opted in to the relaxed ABI. + */ +static int zero; +static int one = 1; + +static struct ctl_table tagged_addr_sysctl_table[] = { + { + .procname = "tagged_addr", + .mode = 0644, + .data = &tagged_addr_prctl_allowed, + .maxlen = sizeof(int), + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, + { } +}; + +static int __init tagged_addr_init(void) +{ + if (!register_sysctl("abi", tagged_addr_sysctl_table)) + return -EINVAL; + return 0; +} + +core_initcall(tagged_addr_init); diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 094bb03b9cc2..2e927b3e9d6c 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -229,4 +229,9 @@ struct prctl_mm_map { # define PR_PAC_APDBKEY (1UL << 3) # define PR_PAC_APGAKEY (1UL << 4) +/* Tagged user address controls for arm64 */ +#define PR_SET_TAGGED_ADDR_CTRL 55 +#define PR_GET_TAGGED_ADDR_CTRL 56 +# define PR_TAGGED_ADDR_ENABLE (1UL << 0) + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 2969304c29fe..ec48396b4943 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -124,6 +124,12 @@ #ifndef PAC_RESET_KEYS # define PAC_RESET_KEYS(a, b) (-EINVAL) #endif +#ifndef SET_TAGGED_ADDR_CTRL +# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL) +#endif +#ifndef GET_TAGGED_ADDR_CTRL +# define GET_TAGGED_ADDR_CTRL() (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2492,6 +2498,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = PAC_RESET_KEYS(me, arg2); break; + case PR_SET_TAGGED_ADDR_CTRL: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = SET_TAGGED_ADDR_CTRL(arg2); + break; + case PR_GET_TAGGED_ADDR_CTRL: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error = GET_TAGGED_ADDR_CTRL(); + break; default: error = -EINVAL; break; -- 2.22.0.rc2.383.gf4fbbf30c2-goog
next prev parent reply index Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov 2019-06-12 14:26 ` Vincenzo Frascino 2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov 2019-06-12 14:28 ` Vincenzo Frascino 2019-06-12 11:43 ` Andrey Konovalov [this message] 2019-06-12 14:30 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Vincenzo Frascino 2019-06-12 14:55 ` Catalin Marinas 2019-06-13 11:02 ` Dave Martin 2019-06-13 15:26 ` Catalin Marinas 2019-06-14 5:13 ` Kees Cook 2019-06-18 9:18 ` Dave Martin 2019-06-13 11:16 ` Dave Martin 2019-06-13 15:35 ` Catalin Marinas 2019-06-13 15:45 ` Vincenzo Frascino 2019-06-13 15:57 ` Catalin Marinas 2019-06-13 16:15 ` Vincenzo Frascino 2019-06-17 13:56 ` Catalin Marinas 2019-06-17 16:56 ` Szabolcs Nagy 2019-06-17 16:57 ` Evgenii Stepanov 2019-06-17 17:18 ` Catalin Marinas 2019-06-17 21:59 ` Evgenii Stepanov 2019-06-19 14:45 ` Andrey Konovalov 2019-06-19 15:29 ` Catalin Marinas 2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov 2019-06-12 14:31 ` Vincenzo Frascino 2019-06-19 15:55 ` Khalid Aziz 2019-06-19 16:46 ` Khalid Aziz 2019-06-24 14:22 ` Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov 2019-06-12 14:33 ` Vincenzo Frascino 2019-06-19 16:41 ` Khalid Aziz 2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov 2019-06-12 14:34 ` Vincenzo Frascino 2019-06-19 16:48 ` Khalid Aziz 2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov 2019-06-12 14:35 ` Vincenzo Frascino 2019-06-19 20:01 ` Khalid Aziz 2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov 2019-06-12 14:40 ` Vincenzo Frascino 2019-06-12 11:43 ` [PATCH v17 09/15] drm/amdgpu, " Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov 2019-06-19 20:05 ` Khalid Aziz 2019-06-12 11:43 ` [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register Andrey Konovalov 2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov 2019-06-12 14:41 ` Vincenzo Frascino 2019-06-12 15:58 ` Auger Eric 2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov 2019-06-12 12:30 ` Szabolcs Nagy
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