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Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull rseq fixes from Ingo Molnar: "Various rseq ABI fixes and cleanups: use get_user()/put_user(), validate parameters and use proper uapi types, etc" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rseq/selftests: cleanup: Update comment above rseq_prepare_unload rseq: Remove unused types_32_64.h uapi header rseq: uapi: Declare rseq_cs field as union, update includes rseq: uapi: Update uapi comments rseq: Use get_user/put_user rather than __get_user/__put_user rseq: Use __u64 for rseq_cs fields, validate user inputs
This commit is contained in:
Linus Torvalds
commit
ae4ea3975d
@ -10,13 +10,8 @@
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* Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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*/
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#ifdef __KERNEL__
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# include <linux/types.h>
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#else
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# include <stdint.h>
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#endif
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#include <linux/types_32_64.h>
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#include <linux/types.h>
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#include <asm/byteorder.h>
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enum rseq_cpu_id_state {
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RSEQ_CPU_ID_UNINITIALIZED = -1,
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@ -52,10 +47,10 @@ struct rseq_cs {
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__u32 version;
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/* enum rseq_cs_flags */
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__u32 flags;
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LINUX_FIELD_u32_u64(start_ip);
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__u64 start_ip;
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/* Offset from start_ip. */
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LINUX_FIELD_u32_u64(post_commit_offset);
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LINUX_FIELD_u32_u64(abort_ip);
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__u64 post_commit_offset;
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__u64 abort_ip;
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} __attribute__((aligned(4 * sizeof(__u64))));
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/*
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@ -67,28 +62,30 @@ struct rseq_cs {
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struct rseq {
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/*
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* Restartable sequences cpu_id_start field. Updated by the
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* kernel, and read by user-space with single-copy atomicity
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* semantics. Aligned on 32-bit. Always contains a value in the
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* range of possible CPUs, although the value may not be the
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* actual current CPU (e.g. if rseq is not initialized). This
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* CPU number value should always be compared against the value
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* of the cpu_id field before performing a rseq commit or
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* returning a value read from a data structure indexed using
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* the cpu_id_start value.
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* kernel. Read by user-space with single-copy atomicity
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* semantics. This field should only be read by the thread which
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* registered this data structure. Aligned on 32-bit. Always
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* contains a value in the range of possible CPUs, although the
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* value may not be the actual current CPU (e.g. if rseq is not
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* initialized). This CPU number value should always be compared
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* against the value of the cpu_id field before performing a rseq
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* commit or returning a value read from a data structure indexed
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* using the cpu_id_start value.
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*/
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__u32 cpu_id_start;
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/*
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* Restartable sequences cpu_id field. Updated by the kernel,
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* and read by user-space with single-copy atomicity semantics.
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* Aligned on 32-bit. Values RSEQ_CPU_ID_UNINITIALIZED and
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* RSEQ_CPU_ID_REGISTRATION_FAILED have a special semantic: the
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* former means "rseq uninitialized", and latter means "rseq
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* initialization failed". This value is meant to be read within
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* rseq critical sections and compared with the cpu_id_start
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* value previously read, before performing the commit instruction,
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* or read and compared with the cpu_id_start value before returning
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* a value loaded from a data structure indexed using the
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* cpu_id_start value.
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* Restartable sequences cpu_id field. Updated by the kernel.
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* Read by user-space with single-copy atomicity semantics. This
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* field should only be read by the thread which registered this
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* data structure. Aligned on 32-bit. Values
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* RSEQ_CPU_ID_UNINITIALIZED and RSEQ_CPU_ID_REGISTRATION_FAILED
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* have a special semantic: the former means "rseq uninitialized",
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* and latter means "rseq initialization failed". This value is
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* meant to be read within rseq critical sections and compared
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* with the cpu_id_start value previously read, before performing
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* the commit instruction, or read and compared with the
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* cpu_id_start value before returning a value loaded from a data
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* structure indexed using the cpu_id_start value.
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*/
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__u32 cpu_id;
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/*
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@ -105,27 +102,44 @@ struct rseq {
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* targeted by the rseq_cs. Also needs to be set to NULL by user-space
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* before reclaiming memory that contains the targeted struct rseq_cs.
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*
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* Read and set by the kernel with single-copy atomicity semantics.
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* Set by user-space with single-copy atomicity semantics. Aligned
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* on 64-bit.
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* Read and set by the kernel. Set by user-space with single-copy
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* atomicity semantics. This field should only be updated by the
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* thread which registered this data structure. Aligned on 64-bit.
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*/
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LINUX_FIELD_u32_u64(rseq_cs);
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union {
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__u64 ptr64;
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#ifdef __LP64__
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__u64 ptr;
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#else
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struct {
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#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
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__u32 padding; /* Initialized to zero. */
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__u32 ptr32;
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#else /* LITTLE */
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__u32 ptr32;
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__u32 padding; /* Initialized to zero. */
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#endif /* ENDIAN */
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} ptr;
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#endif
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} rseq_cs;
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/*
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* - RSEQ_DISABLE flag:
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* Restartable sequences flags field.
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*
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* This field should only be updated by the thread which
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* registered this data structure. Read by the kernel.
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* Mainly used for single-stepping through rseq critical sections
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* with debuggers.
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*
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* Fallback fast-track flag for single-stepping.
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* Set by user-space if lack of progress is detected.
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* Cleared by user-space after rseq finish.
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* Read by the kernel.
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* - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
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* Inhibit instruction sequence block restart and event
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* counter increment on preemption for this thread.
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* Inhibit instruction sequence block restart on preemption
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* for this thread.
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* - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
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* Inhibit instruction sequence block restart and event
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* counter increment on signal delivery for this thread.
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* Inhibit instruction sequence block restart on signal
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* delivery for this thread.
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* - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
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* Inhibit instruction sequence block restart and event
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* counter increment on migration for this thread.
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* Inhibit instruction sequence block restart on migration for
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* this thread.
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*/
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__u32 flags;
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} __attribute__((aligned(4 * sizeof(__u64))));
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@ -1,50 +0,0 @@
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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
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#ifndef _UAPI_LINUX_TYPES_32_64_H
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#define _UAPI_LINUX_TYPES_32_64_H
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/*
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* linux/types_32_64.h
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*
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* Integer type declaration for pointers across 32-bit and 64-bit systems.
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*
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* Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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*/
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#ifdef __KERNEL__
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# include <linux/types.h>
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#else
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# include <stdint.h>
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#endif
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#include <asm/byteorder.h>
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#ifdef __BYTE_ORDER
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# if (__BYTE_ORDER == __BIG_ENDIAN)
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# define LINUX_BYTE_ORDER_BIG_ENDIAN
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# else
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# define LINUX_BYTE_ORDER_LITTLE_ENDIAN
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# endif
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#else
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# ifdef __BIG_ENDIAN
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# define LINUX_BYTE_ORDER_BIG_ENDIAN
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# else
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# define LINUX_BYTE_ORDER_LITTLE_ENDIAN
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# endif
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#endif
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#ifdef __LP64__
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# define LINUX_FIELD_u32_u64(field) __u64 field
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# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) field = (intptr_t)v
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#else
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# ifdef LINUX_BYTE_ORDER_BIG_ENDIAN
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# define LINUX_FIELD_u32_u64(field) __u32 field ## _padding, field
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# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) \
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field ## _padding = 0, field = (intptr_t)v
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# else
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# define LINUX_FIELD_u32_u64(field) __u32 field, field ## _padding
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# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) \
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field = (intptr_t)v, field ## _padding = 0
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# endif
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#endif
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#endif /* _UAPI_LINUX_TYPES_32_64_H */
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@ -85,9 +85,9 @@ static int rseq_update_cpu_id(struct task_struct *t)
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{
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u32 cpu_id = raw_smp_processor_id();
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if (__put_user(cpu_id, &t->rseq->cpu_id_start))
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if (put_user(cpu_id, &t->rseq->cpu_id_start))
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return -EFAULT;
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if (__put_user(cpu_id, &t->rseq->cpu_id))
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if (put_user(cpu_id, &t->rseq->cpu_id))
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return -EFAULT;
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trace_rseq_update(t);
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return 0;
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@ -100,14 +100,14 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t)
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/*
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* Reset cpu_id_start to its initial state (0).
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*/
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if (__put_user(cpu_id_start, &t->rseq->cpu_id_start))
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if (put_user(cpu_id_start, &t->rseq->cpu_id_start))
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return -EFAULT;
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/*
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* Reset cpu_id to RSEQ_CPU_ID_UNINITIALIZED, so any user coming
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* in after unregistration can figure out that rseq needs to be
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* registered again.
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*/
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if (__put_user(cpu_id, &t->rseq->cpu_id))
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if (put_user(cpu_id, &t->rseq->cpu_id))
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return -EFAULT;
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return 0;
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}
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@ -115,29 +115,36 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t)
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static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
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{
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struct rseq_cs __user *urseq_cs;
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unsigned long ptr;
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u64 ptr;
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u32 __user *usig;
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u32 sig;
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int ret;
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ret = __get_user(ptr, &t->rseq->rseq_cs);
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if (ret)
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return ret;
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if (copy_from_user(&ptr, &t->rseq->rseq_cs.ptr64, sizeof(ptr)))
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return -EFAULT;
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if (!ptr) {
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memset(rseq_cs, 0, sizeof(*rseq_cs));
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return 0;
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}
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urseq_cs = (struct rseq_cs __user *)ptr;
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if (ptr >= TASK_SIZE)
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return -EINVAL;
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urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
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if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
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return -EFAULT;
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if (rseq_cs->version > 0)
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return -EINVAL;
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if (rseq_cs->start_ip >= TASK_SIZE ||
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rseq_cs->start_ip + rseq_cs->post_commit_offset >= TASK_SIZE ||
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rseq_cs->abort_ip >= TASK_SIZE ||
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rseq_cs->version > 0)
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return -EINVAL;
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/* Check for overflow. */
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if (rseq_cs->start_ip + rseq_cs->post_commit_offset < rseq_cs->start_ip)
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return -EINVAL;
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/* Ensure that abort_ip is not in the critical section. */
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if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
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return -EINVAL;
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usig = (u32 __user *)(rseq_cs->abort_ip - sizeof(u32));
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usig = (u32 __user *)(unsigned long)(rseq_cs->abort_ip - sizeof(u32));
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ret = get_user(sig, usig);
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if (ret)
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return ret;
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@ -146,7 +153,7 @@ static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
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printk_ratelimited(KERN_WARNING
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"Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
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sig, current->rseq_sig, current->pid, usig);
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return -EPERM;
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return -EINVAL;
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}
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return 0;
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}
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@ -157,7 +164,7 @@ static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
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int ret;
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/* Get thread flags. */
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ret = __get_user(flags, &t->rseq->flags);
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ret = get_user(flags, &t->rseq->flags);
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if (ret)
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return ret;
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@ -195,9 +202,11 @@ static int clear_rseq_cs(struct task_struct *t)
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* of code outside of the rseq assembly block. This performs
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* a lazy clear of the rseq_cs field.
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*
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* Set rseq_cs to NULL with single-copy atomicity.
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* Set rseq_cs to NULL.
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*/
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return __put_user(0UL, &t->rseq->rseq_cs);
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if (clear_user(&t->rseq->rseq_cs.ptr64, sizeof(t->rseq->rseq_cs.ptr64)))
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return -EFAULT;
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return 0;
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}
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/*
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@ -133,17 +133,27 @@ static inline uint32_t rseq_current_cpu(void)
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return cpu;
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}
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static inline void rseq_clear_rseq_cs(void)
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{
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#ifdef __LP64__
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__rseq_abi.rseq_cs.ptr = 0;
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#else
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__rseq_abi.rseq_cs.ptr.ptr32 = 0;
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#endif
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}
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/*
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* rseq_prepare_unload() should be invoked by each thread using rseq_finish*()
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* at least once between their last rseq_finish*() and library unload of the
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* library defining the rseq critical section (struct rseq_cs). This also
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* applies to use of rseq in code generated by JIT: rseq_prepare_unload()
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* should be invoked at least once by each thread using rseq_finish*() before
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* reclaim of the memory holding the struct rseq_cs.
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* rseq_prepare_unload() should be invoked by each thread executing a rseq
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* critical section at least once between their last critical section and
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* library unload of the library defining the rseq critical section
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* (struct rseq_cs). This also applies to use of rseq in code generated by
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* JIT: rseq_prepare_unload() should be invoked at least once by each
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* thread executing a rseq critical section before reclaim of the memory
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* holding the struct rseq_cs.
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*/
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static inline void rseq_prepare_unload(void)
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{
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__rseq_abi.rseq_cs = 0;
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rseq_clear_rseq_cs();
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}
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#endif /* RSEQ_H_ */
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