diff options
Diffstat (limited to 'pkg/sentry/platform/safecopy')
| -rw-r--r-- | pkg/sentry/platform/safecopy/BUILD | 31 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/LICENSE | 27 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/atomic_amd64.s | 136 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/atomic_arm64.s | 126 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/memclr_amd64.s | 147 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/memclr_arm64.s | 74 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/memcpy_amd64.s | 250 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/memcpy_arm64.s | 78 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/safecopy.go | 144 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/safecopy_test.go | 617 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/safecopy_unsafe.go | 335 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/sighandler_amd64.s | 133 | ||||
| -rw-r--r-- | pkg/sentry/platform/safecopy/sighandler_arm64.s | 143 |
13 files changed, 0 insertions, 2241 deletions
diff --git a/pkg/sentry/platform/safecopy/BUILD b/pkg/sentry/platform/safecopy/BUILD deleted file mode 100644 index 6769cd0a5..000000000 --- a/pkg/sentry/platform/safecopy/BUILD +++ /dev/null @@ -1,31 +0,0 @@ -load("//tools/go_stateify:defs.bzl", "go_library") -load("@io_bazel_rules_go//go:def.bzl", "go_test") - -package(licenses = ["notice"]) - -go_library( - name = "safecopy", - srcs = [ - "atomic_amd64.s", - "atomic_arm64.s", - "memclr_amd64.s", - "memclr_arm64.s", - "memcpy_amd64.s", - "memcpy_arm64.s", - "safecopy.go", - "safecopy_unsafe.go", - "sighandler_amd64.s", - "sighandler_arm64.s", - ], - importpath = "gvisor.dev/gvisor/pkg/sentry/platform/safecopy", - visibility = ["//pkg/sentry:internal"], - deps = ["//pkg/syserror"], -) - -go_test( - name = "safecopy_test", - srcs = [ - "safecopy_test.go", - ], - embed = [":safecopy"], -) diff --git a/pkg/sentry/platform/safecopy/LICENSE b/pkg/sentry/platform/safecopy/LICENSE deleted file mode 100644 index 6a66aea5e..000000000 --- a/pkg/sentry/platform/safecopy/LICENSE +++ /dev/null @@ -1,27 +0,0 @@ -Copyright (c) 2009 The Go Authors. All rights reserved. - -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions are -met: - - * Redistributions of source code must retain the above copyright -notice, this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above -copyright notice, this list of conditions and the following disclaimer -in the documentation and/or other materials provided with the -distribution. - * Neither the name of Google Inc. nor the names of its -contributors may be used to endorse or promote products derived from -this software without specific prior written permission. - -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/pkg/sentry/platform/safecopy/atomic_amd64.s b/pkg/sentry/platform/safecopy/atomic_amd64.s deleted file mode 100644 index a0cd78f33..000000000 --- a/pkg/sentry/platform/safecopy/atomic_amd64.s +++ /dev/null @@ -1,136 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -#include "textflag.h" - -// handleSwapUint32Fault returns the value stored in DI. Control is transferred -// to it when swapUint32 below receives SIGSEGV or SIGBUS, with the signal -// number stored in DI. -// -// It must have the same frame configuration as swapUint32 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleSwapUint32Fault(SB), NOSPLIT, $0-24 - MOVL DI, sig+20(FP) - RET - -// swapUint32 atomically stores new into *addr and returns (the previous *addr -// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the -// value of old is unspecified, and sig is the number of the signal that was -// received. -// -// Preconditions: addr must be aligned to a 4-byte boundary. -// -//func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32) -TEXT ·swapUint32(SB), NOSPLIT, $0-24 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleSwapUint32Fault will store a different value in this address. - MOVL $0, sig+20(FP) - - MOVQ addr+0(FP), DI - MOVL new+8(FP), AX - XCHGL AX, 0(DI) - MOVL AX, old+16(FP) - RET - -// handleSwapUint64Fault returns the value stored in DI. Control is transferred -// to it when swapUint64 below receives SIGSEGV or SIGBUS, with the signal -// number stored in DI. -// -// It must have the same frame configuration as swapUint64 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleSwapUint64Fault(SB), NOSPLIT, $0-28 - MOVL DI, sig+24(FP) - RET - -// swapUint64 atomically stores new into *addr and returns (the previous *addr -// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the -// value of old is unspecified, and sig is the number of the signal that was -// received. -// -// Preconditions: addr must be aligned to a 8-byte boundary. -// -//func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32) -TEXT ·swapUint64(SB), NOSPLIT, $0-28 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleSwapUint64Fault will store a different value in this address. - MOVL $0, sig+24(FP) - - MOVQ addr+0(FP), DI - MOVQ new+8(FP), AX - XCHGQ AX, 0(DI) - MOVQ AX, old+16(FP) - RET - -// handleCompareAndSwapUint32Fault returns the value stored in DI. Control is -// transferred to it when swapUint64 below receives SIGSEGV or SIGBUS, with the -// signal number stored in DI. -// -// It must have the same frame configuration as compareAndSwapUint32 so that it -// can undo any potential call frame set up by the assembler. -TEXT handleCompareAndSwapUint32Fault(SB), NOSPLIT, $0-24 - MOVL DI, sig+20(FP) - RET - -// compareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns -// (the value previously stored at addr, 0). If a SIGSEGV or SIGBUS signal is -// received during the operation, the value of prev is unspecified, and sig is -// the number of the signal that was received. -// -// Preconditions: addr must be aligned to a 4-byte boundary. -// -//func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32) -TEXT ·compareAndSwapUint32(SB), NOSPLIT, $0-24 - // Store 0 as the returned signal number. If we run to completion, this is - // the value the caller will see; if a signal is received, - // handleCompareAndSwapUint32Fault will store a different value in this - // address. - MOVL $0, sig+20(FP) - - MOVQ addr+0(FP), DI - MOVL old+8(FP), AX - MOVL new+12(FP), DX - LOCK - CMPXCHGL DX, 0(DI) - MOVL AX, prev+16(FP) - RET - -// handleLoadUint32Fault returns the value stored in DI. Control is transferred -// to it when LoadUint32 below receives SIGSEGV or SIGBUS, with the signal -// number stored in DI. -// -// It must have the same frame configuration as loadUint32 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleLoadUint32Fault(SB), NOSPLIT, $0-16 - MOVL DI, sig+12(FP) - RET - -// loadUint32 atomically loads *addr and returns it. If a SIGSEGV or SIGBUS -// signal is received, the value returned is unspecified, and sig is the number -// of the signal that was received. -// -// Preconditions: addr must be aligned to a 4-byte boundary. -// -//func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32) -TEXT ·loadUint32(SB), NOSPLIT, $0-16 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleLoadUint32Fault will store a different value in this address. - MOVL $0, sig+12(FP) - - MOVQ addr+0(FP), AX - MOVL (AX), BX - MOVL BX, val+8(FP) - RET diff --git a/pkg/sentry/platform/safecopy/atomic_arm64.s b/pkg/sentry/platform/safecopy/atomic_arm64.s deleted file mode 100644 index d58ed71f7..000000000 --- a/pkg/sentry/platform/safecopy/atomic_arm64.s +++ /dev/null @@ -1,126 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "textflag.h" - -// handleSwapUint32Fault returns the value stored in R1. Control is transferred -// to it when swapUint32 below receives SIGSEGV or SIGBUS, with the signal -// number stored in R1. -// -// It must have the same frame configuration as swapUint32 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleSwapUint32Fault(SB), NOSPLIT, $0-24 - MOVW R1, sig+20(FP) - RET - -// See the corresponding doc in safecopy_unsafe.go -// -// The code is derived from Go source runtime/internal/atomic.Xchg. -// -//func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32) -TEXT ·swapUint32(SB), NOSPLIT, $0-24 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleSwapUint32Fault will store a different value in this address. - MOVW $0, sig+20(FP) -again: - MOVD addr+0(FP), R0 - MOVW new+8(FP), R1 - LDAXRW (R0), R2 - STLXRW R1, (R0), R3 - CBNZ R3, again - MOVW R2, old+16(FP) - RET - -// handleSwapUint64Fault returns the value stored in R1. Control is transferred -// to it when swapUint64 below receives SIGSEGV or SIGBUS, with the signal -// number stored in R1. -// -// It must have the same frame configuration as swapUint64 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleSwapUint64Fault(SB), NOSPLIT, $0-28 - MOVW R1, sig+24(FP) - RET - -// See the corresponding doc in safecopy_unsafe.go -// -// The code is derived from Go source runtime/internal/atomic.Xchg64. -// -//func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32) -TEXT ·swapUint64(SB), NOSPLIT, $0-28 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleSwapUint64Fault will store a different value in this address. - MOVW $0, sig+24(FP) -again: - MOVD addr+0(FP), R0 - MOVD new+8(FP), R1 - LDAXR (R0), R2 - STLXR R1, (R0), R3 - CBNZ R3, again - MOVD R2, old+16(FP) - RET - -// handleCompareAndSwapUint32Fault returns the value stored in R1. Control is -// transferred to it when compareAndSwapUint32 below receives SIGSEGV or SIGBUS, -// with the signal number stored in R1. -// -// It must have the same frame configuration as compareAndSwapUint32 so that it -// can undo any potential call frame set up by the assembler. -TEXT handleCompareAndSwapUint32Fault(SB), NOSPLIT, $0-24 - MOVW R1, sig+20(FP) - RET - -// See the corresponding doc in safecopy_unsafe.go -// -// The code is derived from Go source runtime/internal/atomic.Cas. -// -//func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32) -TEXT ·compareAndSwapUint32(SB), NOSPLIT, $0-24 - // Store 0 as the returned signal number. If we run to completion, this is - // the value the caller will see; if a signal is received, - // handleCompareAndSwapUint32Fault will store a different value in this - // address. - MOVW $0, sig+20(FP) - - MOVD addr+0(FP), R0 - MOVW old+8(FP), R1 - MOVW new+12(FP), R2 -again: - LDAXRW (R0), R3 - CMPW R1, R3 - BNE done - STLXRW R2, (R0), R4 - CBNZ R4, again -done: - MOVW R3, prev+16(FP) - RET - -// handleLoadUint32Fault returns the value stored in DI. Control is transferred -// to it when LoadUint32 below receives SIGSEGV or SIGBUS, with the signal -// number stored in DI. -// -// It must have the same frame configuration as loadUint32 so that it can undo -// any potential call frame set up by the assembler. -TEXT handleLoadUint32Fault(SB), NOSPLIT, $0-16 - MOVW R1, sig+12(FP) - RET - -// loadUint32 atomically loads *addr and returns it. If a SIGSEGV or SIGBUS -// signal is received, the value returned is unspecified, and sig is the number -// of the signal that was received. -// -// Preconditions: addr must be aligned to a 4-byte boundary. -// -//func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32) -TEXT ·loadUint32(SB), NOSPLIT, $0-16 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleLoadUint32Fault will store a different value in this address. - MOVW $0, sig+12(FP) - - MOVD addr+0(FP), R0 - LDARW (R0), R1 - MOVW R1, val+8(FP) - RET diff --git a/pkg/sentry/platform/safecopy/memclr_amd64.s b/pkg/sentry/platform/safecopy/memclr_amd64.s deleted file mode 100644 index 64cf32f05..000000000 --- a/pkg/sentry/platform/safecopy/memclr_amd64.s +++ /dev/null @@ -1,147 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "textflag.h" - -// handleMemclrFault returns (the value stored in AX, the value stored in DI). -// Control is transferred to it when memclr below receives SIGSEGV or SIGBUS, -// with the faulting address stored in AX and the signal number stored in DI. -// -// It must have the same frame configuration as memclr so that it can undo any -// potential call frame set up by the assembler. -TEXT handleMemclrFault(SB), NOSPLIT, $0-28 - MOVQ AX, addr+16(FP) - MOVL DI, sig+24(FP) - RET - -// memclr sets the n bytes following ptr to zeroes. If a SIGSEGV or SIGBUS -// signal is received during the write, it returns the address that caused the -// fault and the number of the signal that was received. Otherwise, it returns -// an unspecified address and a signal number of 0. -// -// Data is written in order, such that if a fault happens at address p, it is -// safe to assume that all data before p-maxRegisterSize has already been -// successfully written. -// -// The code is derived from runtime.memclrNoHeapPointers. -// -// func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) -TEXT ·memclr(SB), NOSPLIT, $0-28 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleMemclrFault will store a different value in this address. - MOVL $0, sig+24(FP) - - MOVQ ptr+0(FP), DI - MOVQ n+8(FP), BX - XORQ AX, AX - - // MOVOU seems always faster than REP STOSQ. -tail: - TESTQ BX, BX - JEQ _0 - CMPQ BX, $2 - JBE _1or2 - CMPQ BX, $4 - JBE _3or4 - CMPQ BX, $8 - JB _5through7 - JE _8 - CMPQ BX, $16 - JBE _9through16 - PXOR X0, X0 - CMPQ BX, $32 - JBE _17through32 - CMPQ BX, $64 - JBE _33through64 - CMPQ BX, $128 - JBE _65through128 - CMPQ BX, $256 - JBE _129through256 - // TODO: use branch table and BSR to make this just a single dispatch - // TODO: for really big clears, use MOVNTDQ, even without AVX2. - -loop: - MOVOU X0, 0(DI) - MOVOU X0, 16(DI) - MOVOU X0, 32(DI) - MOVOU X0, 48(DI) - MOVOU X0, 64(DI) - MOVOU X0, 80(DI) - MOVOU X0, 96(DI) - MOVOU X0, 112(DI) - MOVOU X0, 128(DI) - MOVOU X0, 144(DI) - MOVOU X0, 160(DI) - MOVOU X0, 176(DI) - MOVOU X0, 192(DI) - MOVOU X0, 208(DI) - MOVOU X0, 224(DI) - MOVOU X0, 240(DI) - SUBQ $256, BX - ADDQ $256, DI - CMPQ BX, $256 - JAE loop - JMP tail - -_1or2: - MOVB AX, (DI) - MOVB AX, -1(DI)(BX*1) - RET -_0: - RET -_3or4: - MOVW AX, (DI) - MOVW AX, -2(DI)(BX*1) - RET -_5through7: - MOVL AX, (DI) - MOVL AX, -4(DI)(BX*1) - RET -_8: - // We need a separate case for 8 to make sure we clear pointers atomically. - MOVQ AX, (DI) - RET -_9through16: - MOVQ AX, (DI) - MOVQ AX, -8(DI)(BX*1) - RET -_17through32: - MOVOU X0, (DI) - MOVOU X0, -16(DI)(BX*1) - RET -_33through64: - MOVOU X0, (DI) - MOVOU X0, 16(DI) - MOVOU X0, -32(DI)(BX*1) - MOVOU X0, -16(DI)(BX*1) - RET -_65through128: - MOVOU X0, (DI) - MOVOU X0, 16(DI) - MOVOU X0, 32(DI) - MOVOU X0, 48(DI) - MOVOU X0, -64(DI)(BX*1) - MOVOU X0, -48(DI)(BX*1) - MOVOU X0, -32(DI)(BX*1) - MOVOU X0, -16(DI)(BX*1) - RET -_129through256: - MOVOU X0, (DI) - MOVOU X0, 16(DI) - MOVOU X0, 32(DI) - MOVOU X0, 48(DI) - MOVOU X0, 64(DI) - MOVOU X0, 80(DI) - MOVOU X0, 96(DI) - MOVOU X0, 112(DI) - MOVOU X0, -128(DI)(BX*1) - MOVOU X0, -112(DI)(BX*1) - MOVOU X0, -96(DI)(BX*1) - MOVOU X0, -80(DI)(BX*1) - MOVOU X0, -64(DI)(BX*1) - MOVOU X0, -48(DI)(BX*1) - MOVOU X0, -32(DI)(BX*1) - MOVOU X0, -16(DI)(BX*1) - RET diff --git a/pkg/sentry/platform/safecopy/memclr_arm64.s b/pkg/sentry/platform/safecopy/memclr_arm64.s deleted file mode 100644 index 7361b9067..000000000 --- a/pkg/sentry/platform/safecopy/memclr_arm64.s +++ /dev/null @@ -1,74 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "textflag.h" - -// handleMemclrFault returns (the value stored in R0, the value stored in R1). -// Control is transferred to it when memclr below receives SIGSEGV or SIGBUS, -// with the faulting address stored in R0 and the signal number stored in R1. -// -// It must have the same frame configuration as memclr so that it can undo any -// potential call frame set up by the assembler. -TEXT handleMemclrFault(SB), NOSPLIT, $0-28 - MOVD R0, addr+16(FP) - MOVW R1, sig+24(FP) - RET - -// See the corresponding doc in safecopy_unsafe.go -// -// The code is derived from runtime.memclrNoHeapPointers. -// -// func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) -TEXT ·memclr(SB), NOSPLIT, $0-28 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleMemclrFault will store a different value in this address. - MOVW $0, sig+24(FP) - MOVD ptr+0(FP), R0 - MOVD n+8(FP), R1 - - // If size is less than 16 bytes, use tail_zero to zero what remains - CMP $16, R1 - BLT tail_zero - // Get buffer offset into 16 byte aligned address for better performance - ANDS $15, R0, ZR - BNE unaligned_to_16 -aligned_to_16: - LSR $4, R1, R2 -zero_by_16: - STP.P (ZR, ZR), 16(R0) // Store pair with post index. - SUBS $1, R2, R2 - BNE zero_by_16 - ANDS $15, R1, R1 - BEQ end - - // Zero buffer with size=R1 < 16 -tail_zero: - TBZ $3, R1, tail_zero_4 - MOVD.P ZR, 8(R0) -tail_zero_4: - TBZ $2, R1, tail_zero_2 - MOVW.P ZR, 4(R0) -tail_zero_2: - TBZ $1, R1, tail_zero_1 - MOVH.P ZR, 2(R0) -tail_zero_1: - TBZ $0, R1, end - MOVB ZR, (R0) -end: - RET - -unaligned_to_16: - MOVD R0, R2 -head_loop: - MOVBU.P ZR, 1(R0) - ANDS $15, R0, ZR - BNE head_loop - // Adjust length for what remains - SUB R2, R0, R3 - SUB R3, R1 - // If size is less than 16 bytes, use tail_zero to zero what remains - CMP $16, R1 - BLT tail_zero - B aligned_to_16 diff --git a/pkg/sentry/platform/safecopy/memcpy_amd64.s b/pkg/sentry/platform/safecopy/memcpy_amd64.s deleted file mode 100644 index 129691d68..000000000 --- a/pkg/sentry/platform/safecopy/memcpy_amd64.s +++ /dev/null @@ -1,250 +0,0 @@ -// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. -// Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved. -// Portions Copyright 2009 The Go Authors. All rights reserved. -// -// Permission is hereby granted, free of charge, to any person obtaining a copy -// of this software and associated documentation files (the "Software"), to deal -// in the Software without restriction, including without limitation the rights -// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell -// copies of the Software, and to permit persons to whom the Software is -// furnished to do so, subject to the following conditions: -// -// The above copyright notice and this permission notice shall be included in -// all copies or substantial portions of the Software. -// -// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR -// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, -// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE -// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER -// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, -// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN -// THE SOFTWARE. - -#include "textflag.h" - -// handleMemcpyFault returns (the value stored in AX, the value stored in DI). -// Control is transferred to it when memcpy below receives SIGSEGV or SIGBUS, -// with the faulting address stored in AX and the signal number stored in DI. -// -// It must have the same frame configuration as memcpy so that it can undo any -// potential call frame set up by the assembler. -TEXT handleMemcpyFault(SB), NOSPLIT, $0-36 - MOVQ AX, addr+24(FP) - MOVL DI, sig+32(FP) - RET - -// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received -// during the copy, it returns the address that caused the fault and the number -// of the signal that was received. Otherwise, it returns an unspecified address -// and a signal number of 0. -// -// Data is copied in order, such that if a fault happens at address p, it is -// safe to assume that all data before p-maxRegisterSize has already been -// successfully copied. -// -// The code is derived from the forward copying part of runtime.memmove. -// -// func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) -TEXT ·memcpy(SB), NOSPLIT, $0-36 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleMemcpyFault will store a different value in this address. - MOVL $0, sig+32(FP) - - MOVQ to+0(FP), DI - MOVQ from+8(FP), SI - MOVQ n+16(FP), BX - - // REP instructions have a high startup cost, so we handle small sizes - // with some straightline code. The REP MOVSQ instruction is really fast - // for large sizes. The cutover is approximately 2K. -tail: - // move_129through256 or smaller work whether or not the source and the - // destination memory regions overlap because they load all data into - // registers before writing it back. move_256through2048 on the other - // hand can be used only when the memory regions don't overlap or the copy - // direction is forward. - TESTQ BX, BX - JEQ move_0 - CMPQ BX, $2 - JBE move_1or2 - CMPQ BX, $4 - JBE move_3or4 - CMPQ BX, $8 - JB move_5through7 - JE move_8 - CMPQ BX, $16 - JBE move_9through16 - CMPQ BX, $32 - JBE move_17through32 - CMPQ BX, $64 - JBE move_33through64 - CMPQ BX, $128 - JBE move_65through128 - CMPQ BX, $256 - JBE move_129through256 - // TODO: use branch table and BSR to make this just a single dispatch - -/* - * forward copy loop - */ - CMPQ BX, $2048 - JLS move_256through2048 - - // Check alignment - MOVL SI, AX - ORL DI, AX - TESTL $7, AX - JEQ fwdBy8 - - // Do 1 byte at a time - MOVQ BX, CX - REP; MOVSB - RET - -fwdBy8: - // Do 8 bytes at a time - MOVQ BX, CX - SHRQ $3, CX - ANDQ $7, BX - REP; MOVSQ - JMP tail - -move_1or2: - MOVB (SI), AX - MOVB AX, (DI) - MOVB -1(SI)(BX*1), CX - MOVB CX, -1(DI)(BX*1) - RET -move_0: - RET -move_3or4: - MOVW (SI), AX - MOVW AX, (DI) - MOVW -2(SI)(BX*1), CX - MOVW CX, -2(DI)(BX*1) - RET -move_5through7: - MOVL (SI), AX - MOVL AX, (DI) - MOVL -4(SI)(BX*1), CX - MOVL CX, -4(DI)(BX*1) - RET -move_8: - // We need a separate case for 8 to make sure we write pointers atomically. - MOVQ (SI), AX - MOVQ AX, (DI) - RET -move_9through16: - MOVQ (SI), AX - MOVQ AX, (DI) - MOVQ -8(SI)(BX*1), CX - MOVQ CX, -8(DI)(BX*1) - RET -move_17through32: - MOVOU (SI), X0 - MOVOU X0, (DI) - MOVOU -16(SI)(BX*1), X1 - MOVOU X1, -16(DI)(BX*1) - RET -move_33through64: - MOVOU (SI), X0 - MOVOU X0, (DI) - MOVOU 16(SI), X1 - MOVOU X1, 16(DI) - MOVOU -32(SI)(BX*1), X2 - MOVOU X2, -32(DI)(BX*1) - MOVOU -16(SI)(BX*1), X3 - MOVOU X3, -16(DI)(BX*1) - RET -move_65through128: - MOVOU (SI), X0 - MOVOU X0, (DI) - MOVOU 16(SI), X1 - MOVOU X1, 16(DI) - MOVOU 32(SI), X2 - MOVOU X2, 32(DI) - MOVOU 48(SI), X3 - MOVOU X3, 48(DI) - MOVOU -64(SI)(BX*1), X4 - MOVOU X4, -64(DI)(BX*1) - MOVOU -48(SI)(BX*1), X5 - MOVOU X5, -48(DI)(BX*1) - MOVOU -32(SI)(BX*1), X6 - MOVOU X6, -32(DI)(BX*1) - MOVOU -16(SI)(BX*1), X7 - MOVOU X7, -16(DI)(BX*1) - RET -move_129through256: - MOVOU (SI), X0 - MOVOU X0, (DI) - MOVOU 16(SI), X1 - MOVOU X1, 16(DI) - MOVOU 32(SI), X2 - MOVOU X2, 32(DI) - MOVOU 48(SI), X3 - MOVOU X3, 48(DI) - MOVOU 64(SI), X4 - MOVOU X4, 64(DI) - MOVOU 80(SI), X5 - MOVOU X5, 80(DI) - MOVOU 96(SI), X6 - MOVOU X6, 96(DI) - MOVOU 112(SI), X7 - MOVOU X7, 112(DI) - MOVOU -128(SI)(BX*1), X8 - MOVOU X8, -128(DI)(BX*1) - MOVOU -112(SI)(BX*1), X9 - MOVOU X9, -112(DI)(BX*1) - MOVOU -96(SI)(BX*1), X10 - MOVOU X10, -96(DI)(BX*1) - MOVOU -80(SI)(BX*1), X11 - MOVOU X11, -80(DI)(BX*1) - MOVOU -64(SI)(BX*1), X12 - MOVOU X12, -64(DI)(BX*1) - MOVOU -48(SI)(BX*1), X13 - MOVOU X13, -48(DI)(BX*1) - MOVOU -32(SI)(BX*1), X14 - MOVOU X14, -32(DI)(BX*1) - MOVOU -16(SI)(BX*1), X15 - MOVOU X15, -16(DI)(BX*1) - RET -move_256through2048: - SUBQ $256, BX - MOVOU (SI), X0 - MOVOU X0, (DI) - MOVOU 16(SI), X1 - MOVOU X1, 16(DI) - MOVOU 32(SI), X2 - MOVOU X2, 32(DI) - MOVOU 48(SI), X3 - MOVOU X3, 48(DI) - MOVOU 64(SI), X4 - MOVOU X4, 64(DI) - MOVOU 80(SI), X5 - MOVOU X5, 80(DI) - MOVOU 96(SI), X6 - MOVOU X6, 96(DI) - MOVOU 112(SI), X7 - MOVOU X7, 112(DI) - MOVOU 128(SI), X8 - MOVOU X8, 128(DI) - MOVOU 144(SI), X9 - MOVOU X9, 144(DI) - MOVOU 160(SI), X10 - MOVOU X10, 160(DI) - MOVOU 176(SI), X11 - MOVOU X11, 176(DI) - MOVOU 192(SI), X12 - MOVOU X12, 192(DI) - MOVOU 208(SI), X13 - MOVOU X13, 208(DI) - MOVOU 224(SI), X14 - MOVOU X14, 224(DI) - MOVOU 240(SI), X15 - MOVOU X15, 240(DI) - CMPQ BX, $256 - LEAQ 256(SI), SI - LEAQ 256(DI), DI - JGE move_256through2048 - JMP tail diff --git a/pkg/sentry/platform/safecopy/memcpy_arm64.s b/pkg/sentry/platform/safecopy/memcpy_arm64.s deleted file mode 100644 index e7e541565..000000000 --- a/pkg/sentry/platform/safecopy/memcpy_arm64.s +++ /dev/null @@ -1,78 +0,0 @@ -// Copyright 2014 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "textflag.h" - -// handleMemcpyFault returns (the value stored in R0, the value stored in R1). -// Control is transferred to it when memcpy below receives SIGSEGV or SIGBUS, -// with the faulting address stored in R0 and the signal number stored in R1. -// -// It must have the same frame configuration as memcpy so that it can undo any -// potential call frame set up by the assembler. -TEXT handleMemcpyFault(SB), NOSPLIT, $0-36 - MOVD R0, addr+24(FP) - MOVW R1, sig+32(FP) - RET - -// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received -// during the copy, it returns the address that caused the fault and the number -// of the signal that was received. Otherwise, it returns an unspecified address -// and a signal number of 0. -// -// Data is copied in order, such that if a fault happens at address p, it is -// safe to assume that all data before p-maxRegisterSize has already been -// successfully copied. -// -// The code is derived from the Go source runtime.memmove. -// -// func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) -TEXT ·memcpy(SB), NOSPLIT, $-8-36 - // Store 0 as the returned signal number. If we run to completion, - // this is the value the caller will see; if a signal is received, - // handleMemcpyFault will store a different value in this address. - MOVW $0, sig+32(FP) - - MOVD to+0(FP), R3 - MOVD from+8(FP), R4 - MOVD n+16(FP), R5 - CMP $0, R5 - BNE check - RET - -check: - AND $~7, R5, R7 // R7 is N&~7. - SUB R7, R5, R6 // R6 is N&7. - - // Copying forward proceeds by copying R7/8 words then copying R6 bytes. - // R3 and R4 are advanced as we copy. - - // (There may be implementations of armv8 where copying by bytes until - // at least one of source or dest is word aligned is a worthwhile - // optimization, but the on the one tested so far (xgene) it did not - // make a significance difference.) - - CMP $0, R7 // Do we need to do any word-by-word copying? - BEQ noforwardlarge - ADD R3, R7, R9 // R9 points just past where we copy by word. - -forwardlargeloop: - MOVD.P 8(R4), R8 // R8 is just a scratch register. - MOVD.P R8, 8(R3) - CMP R3, R9 - BNE forwardlargeloop - -noforwardlarge: - CMP $0, R6 // Do we need to do any byte-by-byte copying? - BNE forwardtail - RET - -forwardtail: - ADD R3, R6, R9 // R9 points just past the destination memory. - -forwardtailloop: - MOVBU.P 1(R4), R8 - MOVBU.P R8, 1(R3) - CMP R3, R9 - BNE forwardtailloop - RET diff --git a/pkg/sentry/platform/safecopy/safecopy.go b/pkg/sentry/platform/safecopy/safecopy.go deleted file mode 100644 index 2fb7e5809..000000000 --- a/pkg/sentry/platform/safecopy/safecopy.go +++ /dev/null @@ -1,144 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// Package safecopy provides an efficient implementation of functions to access -// memory that may result in SIGSEGV or SIGBUS being sent to the accessor. -package safecopy - -import ( - "fmt" - "reflect" - "runtime" - "syscall" - - "gvisor.dev/gvisor/pkg/syserror" -) - -// SegvError is returned when a safecopy function receives SIGSEGV. -type SegvError struct { - // Addr is the address at which the SIGSEGV occurred. - Addr uintptr -} - -// Error implements error.Error. -func (e SegvError) Error() string { - return fmt.Sprintf("SIGSEGV at %#x", e.Addr) -} - -// BusError is returned when a safecopy function receives SIGBUS. -type BusError struct { - // Addr is the address at which the SIGBUS occurred. - Addr uintptr -} - -// Error implements error.Error. -func (e BusError) Error() string { - return fmt.Sprintf("SIGBUS at %#x", e.Addr) -} - -// AlignmentError is returned when a safecopy function is passed an address -// that does not meet alignment requirements. -type AlignmentError struct { - // Addr is the invalid address. - Addr uintptr - - // Alignment is the required alignment. - Alignment uintptr -} - -// Error implements error.Error. -func (e AlignmentError) Error() string { - return fmt.Sprintf("address %#x is not aligned to a %d-byte boundary", e.Addr, e.Alignment) -} - -var ( - // The begin and end addresses below are for the functions that are - // checked by the signal handler. - memcpyBegin uintptr - memcpyEnd uintptr - memclrBegin uintptr - memclrEnd uintptr - swapUint32Begin uintptr - swapUint32End uintptr - swapUint64Begin uintptr - swapUint64End uintptr - compareAndSwapUint32Begin uintptr - compareAndSwapUint32End uintptr - loadUint32Begin uintptr - loadUint32End uintptr - - // savedSigSegVHandler is a pointer to the SIGSEGV handler that was - // configured before we replaced it with our own. We still call into it - // when we get a SIGSEGV that is not interesting to us. - savedSigSegVHandler uintptr - - // same a above, but for SIGBUS signals. - savedSigBusHandler uintptr -) - -// signalHandler is our replacement signal handler for SIGSEGV and SIGBUS -// signals. -func signalHandler() - -// FindEndAddress returns the end address (one byte beyond the last) of the -// function that contains the specified address (begin). -func FindEndAddress(begin uintptr) uintptr { - f := runtime.FuncForPC(begin) - if f != nil { - for p := begin; ; p++ { - g := runtime.FuncForPC(p) - if f != g { - return p - } - } - } - return begin -} - -// initializeAddresses initializes the addresses used by the signal handler. -func initializeAddresses() { - // The following functions are written in assembly language, so they won't - // be inlined by the existing compiler/linker. Tests will fail if this - // assumption is violated. - memcpyBegin = reflect.ValueOf(memcpy).Pointer() - memcpyEnd = FindEndAddress(memcpyBegin) - memclrBegin = reflect.ValueOf(memclr).Pointer() - memclrEnd = FindEndAddress(memclrBegin) - swapUint32Begin = reflect.ValueOf(swapUint32).Pointer() - swapUint32End = FindEndAddress(swapUint32Begin) - swapUint64Begin = reflect.ValueOf(swapUint64).Pointer() - swapUint64End = FindEndAddress(swapUint64Begin) - compareAndSwapUint32Begin = reflect.ValueOf(compareAndSwapUint32).Pointer() - compareAndSwapUint32End = FindEndAddress(compareAndSwapUint32Begin) - loadUint32Begin = reflect.ValueOf(loadUint32).Pointer() - loadUint32End = FindEndAddress(loadUint32Begin) -} - -func init() { - initializeAddresses() - if err := ReplaceSignalHandler(syscall.SIGSEGV, reflect.ValueOf(signalHandler).Pointer(), &savedSigSegVHandler); err != nil { - panic(fmt.Sprintf("Unable to set handler for SIGSEGV: %v", err)) - } - if err := ReplaceSignalHandler(syscall.SIGBUS, reflect.ValueOf(signalHandler).Pointer(), &savedSigBusHandler); err != nil { - panic(fmt.Sprintf("Unable to set handler for SIGBUS: %v", err)) - } - syserror.AddErrorUnwrapper(func(e error) (syscall.Errno, bool) { - switch e.(type) { - case SegvError, BusError, AlignmentError: - return syscall.EFAULT, true - default: - return 0, false - } - }) -} diff --git a/pkg/sentry/platform/safecopy/safecopy_test.go b/pkg/sentry/platform/safecopy/safecopy_test.go deleted file mode 100644 index 5818f7f9b..000000000 --- a/pkg/sentry/platform/safecopy/safecopy_test.go +++ /dev/null @@ -1,617 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package safecopy - -import ( - "bytes" - "fmt" - "io/ioutil" - "math/rand" - "os" - "runtime/debug" - "syscall" - "testing" - "unsafe" -) - -// Size of a page in bytes. Cloned from usermem.PageSize to avoid a circular -// dependency. -const pageSize = 4096 - -func initRandom(b []byte) { - for i := range b { - b[i] = byte(rand.Intn(256)) - } -} - -func randBuf(size int) []byte { - b := make([]byte, size) - initRandom(b) - return b -} - -func TestCopyInSuccess(t *testing.T) { - // Test that CopyIn does not return an error when all pages are accessible. - const bufLen = 8192 - a := randBuf(bufLen) - b := make([]byte, bufLen) - - n, err := CopyIn(b, unsafe.Pointer(&a[0])) - if n != bufLen { - t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen) - } - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if !bytes.Equal(a, b) { - t.Errorf("Buffers are not equal when they should be: %v %v", a, b) - } -} - -func TestCopyOutSuccess(t *testing.T) { - // Test that CopyOut does not return an error when all pages are - // accessible. - const bufLen = 8192 - a := randBuf(bufLen) - b := make([]byte, bufLen) - - n, err := CopyOut(unsafe.Pointer(&b[0]), a) - if n != bufLen { - t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen) - } - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if !bytes.Equal(a, b) { - t.Errorf("Buffers are not equal when they should be: %v %v", a, b) - } -} - -func TestCopySuccess(t *testing.T) { - // Test that Copy does not return an error when all pages are accessible. - const bufLen = 8192 - a := randBuf(bufLen) - b := make([]byte, bufLen) - - n, err := Copy(unsafe.Pointer(&b[0]), unsafe.Pointer(&a[0]), bufLen) - if n != bufLen { - t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen) - } - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if !bytes.Equal(a, b) { - t.Errorf("Buffers are not equal when they should be: %v %v", a, b) - } -} - -func TestZeroOutSuccess(t *testing.T) { - // Test that ZeroOut does not return an error when all pages are - // accessible. - const bufLen = 8192 - a := make([]byte, bufLen) - b := randBuf(bufLen) - - n, err := ZeroOut(unsafe.Pointer(&b[0]), bufLen) - if n != bufLen { - t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen) - } - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if !bytes.Equal(a, b) { - t.Errorf("Buffers are not equal when they should be: %v %v", a, b) - } -} - -func TestSwapUint32Success(t *testing.T) { - // Test that SwapUint32 does not return an error when the page is - // accessible. - before := uint32(rand.Int31()) - after := uint32(rand.Int31()) - val := before - - old, err := SwapUint32(unsafe.Pointer(&val), after) - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if old != before { - t.Errorf("Unexpected old value: got %v, want %v", old, before) - } - if val != after { - t.Errorf("Unexpected new value: got %v, want %v", val, after) - } -} - -func TestSwapUint32AlignmentError(t *testing.T) { - // Test that SwapUint32 returns an AlignmentError when passed an unaligned - // address. - data := new(struct{ val uint64 }) - addr := uintptr(unsafe.Pointer(&data.val)) + 1 - want := AlignmentError{Addr: addr, Alignment: 4} - if _, err := SwapUint32(unsafe.Pointer(addr), 1); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } -} - -func TestSwapUint64Success(t *testing.T) { - // Test that SwapUint64 does not return an error when the page is - // accessible. - before := uint64(rand.Int63()) - after := uint64(rand.Int63()) - // "The first word in ... an allocated struct or slice can be relied upon - // to be 64-bit aligned." - sync/atomic docs - data := new(struct{ val uint64 }) - data.val = before - - old, err := SwapUint64(unsafe.Pointer(&data.val), after) - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if old != before { - t.Errorf("Unexpected old value: got %v, want %v", old, before) - } - if data.val != after { - t.Errorf("Unexpected new value: got %v, want %v", data.val, after) - } -} - -func TestSwapUint64AlignmentError(t *testing.T) { - // Test that SwapUint64 returns an AlignmentError when passed an unaligned - // address. - data := new(struct{ val1, val2 uint64 }) - addr := uintptr(unsafe.Pointer(&data.val1)) + 1 - want := AlignmentError{Addr: addr, Alignment: 8} - if _, err := SwapUint64(unsafe.Pointer(addr), 1); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } -} - -func TestCompareAndSwapUint32Success(t *testing.T) { - // Test that CompareAndSwapUint32 does not return an error when the page is - // accessible. - before := uint32(rand.Int31()) - after := uint32(rand.Int31()) - val := before - - old, err := CompareAndSwapUint32(unsafe.Pointer(&val), before, after) - if err != nil { - t.Errorf("Unexpected error: %v", err) - } - if old != before { - t.Errorf("Unexpected old value: got %v, want %v", old, before) - } - if val != after { - t.Errorf("Unexpected new value: got %v, want %v", val, after) - } -} - -func TestCompareAndSwapUint32AlignmentError(t *testing.T) { - // Test that CompareAndSwapUint32 returns an AlignmentError when passed an - // unaligned address. - data := new(struct{ val uint64 }) - addr := uintptr(unsafe.Pointer(&data.val)) + 1 - want := AlignmentError{Addr: addr, Alignment: 4} - if _, err := CompareAndSwapUint32(unsafe.Pointer(addr), 0, 1); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } -} - -// withSegvErrorTestMapping calls fn with a two-page mapping. The first page -// contains random data, and the second page generates SIGSEGV when accessed. -func withSegvErrorTestMapping(t *testing.T, fn func(m []byte)) { - mapping, err := syscall.Mmap(-1, 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE) - if err != nil { - t.Fatalf("Mmap failed: %v", err) - } - defer syscall.Munmap(mapping) - if err := syscall.Mprotect(mapping[pageSize:], syscall.PROT_NONE); err != nil { - t.Fatalf("Mprotect failed: %v", err) - } - initRandom(mapping[:pageSize]) - - fn(mapping) -} - -// withBusErrorTestMapping calls fn with a two-page mapping. The first page -// contains random data, and the second page generates SIGBUS when accessed. -func withBusErrorTestMapping(t *testing.T, fn func(m []byte)) { - f, err := ioutil.TempFile("", "sigbus_test") - if err != nil { - t.Fatalf("TempFile failed: %v", err) - } - defer f.Close() - if err := f.Truncate(pageSize); err != nil { - t.Fatalf("Truncate failed: %v", err) - } - mapping, err := syscall.Mmap(int(f.Fd()), 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED) - if err != nil { - t.Fatalf("Mmap failed: %v", err) - } - defer syscall.Munmap(mapping) - initRandom(mapping[:pageSize]) - - fn(mapping) -} - -func TestCopyInSegvError(t *testing.T) { - // Test that CopyIn returns a SegvError when reaching a page that signals - // SIGSEGV. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - dst := randBuf(pageSize) - n, err := CopyIn(dst, src) - if n != bytesBeforeFault { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopyInBusError(t *testing.T) { - // Test that CopyIn returns a BusError when reaching a page that signals - // SIGBUS. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) { - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - dst := randBuf(pageSize) - n, err := CopyIn(dst, src) - if n != bytesBeforeFault { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopyOutSegvError(t *testing.T) { - // Test that CopyOut returns a SegvError when reaching a page that signals - // SIGSEGV. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - src := randBuf(pageSize) - n, err := CopyOut(dst, src) - if n != bytesBeforeFault { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopyOutBusError(t *testing.T) { - // Test that CopyOut returns a BusError when reaching a page that signals - // SIGBUS. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - src := randBuf(pageSize) - n, err := CopyOut(dst, src) - if n != bytesBeforeFault { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopySourceSegvError(t *testing.T) { - // Test that Copy returns a SegvError when copying from a page that signals - // SIGSEGV. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - dst := randBuf(pageSize) - n, err := Copy(unsafe.Pointer(&dst[0]), src, pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopySourceBusError(t *testing.T) { - // Test that Copy returns a BusError when copying from a page that signals - // SIGBUS. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) { - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - dst := randBuf(pageSize) - n, err := Copy(unsafe.Pointer(&dst[0]), src, pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopyDestinationSegvError(t *testing.T) { - // Test that Copy returns a SegvError when copying to a page that signals - // SIGSEGV. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - src := randBuf(pageSize) - n, err := Copy(dst, unsafe.Pointer(&src[0]), pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestCopyDestinationBusError(t *testing.T) { - // Test that Copy returns a BusError when copying to a page that signals - // SIGBUS. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) { - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - src := randBuf(pageSize) - n, err := Copy(dst, unsafe.Pointer(&src[0]), pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault) - } - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) { - t.Errorf("Buffers are not equal when they should be: %v %v", got, want) - } - }) - }) - } -} - -func TestZeroOutSegvError(t *testing.T) { - // Test that ZeroOut returns a SegvError when reaching a page that signals - // SIGSEGV. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting write %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) { - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - n, err := ZeroOut(dst, pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected write length: got %v, want %v", n, bytesBeforeFault) - } - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], make([]byte, bytesBeforeFault); !bytes.Equal(got, want) { - t.Errorf("Non-zero bytes in written part of mapping: %v", got) - } - }) - }) - } -} - -func TestZeroOutBusError(t *testing.T) { - // Test that ZeroOut returns a BusError when reaching a page that signals - // SIGBUS. - for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ { - t.Run(fmt.Sprintf("starting write %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) { - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault)) - n, err := ZeroOut(dst, pageSize) - if n != uintptr(bytesBeforeFault) { - t.Errorf("Unexpected write length: got %v, want %v", n, bytesBeforeFault) - } - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - if got, want := mapping[pageSize-bytesBeforeFault:pageSize], make([]byte, bytesBeforeFault); !bytes.Equal(got, want) { - t.Errorf("Non-zero bytes in written part of mapping: %v", got) - } - }) - }) - } -} - -func TestSwapUint32SegvError(t *testing.T) { - // Test that SwapUint32 returns a SegvError when reaching a page that - // signals SIGSEGV. - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := SwapUint32(unsafe.Pointer(secondPage), 1) - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func TestSwapUint32BusError(t *testing.T) { - // Test that SwapUint32 returns a BusError when reaching a page that - // signals SIGBUS. - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := SwapUint32(unsafe.Pointer(secondPage), 1) - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func TestSwapUint64SegvError(t *testing.T) { - // Test that SwapUint64 returns a SegvError when reaching a page that - // signals SIGSEGV. - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := SwapUint64(unsafe.Pointer(secondPage), 1) - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func TestSwapUint64BusError(t *testing.T) { - // Test that SwapUint64 returns a BusError when reaching a page that - // signals SIGBUS. - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := SwapUint64(unsafe.Pointer(secondPage), 1) - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func TestCompareAndSwapUint32SegvError(t *testing.T) { - // Test that CompareAndSwapUint32 returns a SegvError when reaching a page - // that signals SIGSEGV. - withSegvErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := CompareAndSwapUint32(unsafe.Pointer(secondPage), 0, 1) - if want := (SegvError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func TestCompareAndSwapUint32BusError(t *testing.T) { - // Test that CompareAndSwapUint32 returns a BusError when reaching a page - // that signals SIGBUS. - withBusErrorTestMapping(t, func(mapping []byte) { - secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize - _, err := CompareAndSwapUint32(unsafe.Pointer(secondPage), 0, 1) - if want := (BusError{secondPage}); err != want { - t.Errorf("Unexpected error: got %v, want %v", err, want) - } - }) -} - -func testCopy(dst, src []byte) (panicked bool) { - defer func() { - if r := recover(); r != nil { - panicked = true - } - }() - debug.SetPanicOnFault(true) - copy(dst, src) - return -} - -func TestSegVOnMemmove(t *testing.T) { - // Test that SIGSEGVs received by runtime.memmove when *not* doing - // CopyIn or CopyOut work gets propagated to the runtime. - const bufLen = pageSize - a, err := syscall.Mmap(-1, 0, bufLen, syscall.PROT_NONE, syscall.MAP_ANON|syscall.MAP_PRIVATE) - if err != nil { - t.Fatalf("Mmap failed: %v", err) - - } - defer syscall.Munmap(a) - b := randBuf(bufLen) - - if !testCopy(b, a) { - t.Fatalf("testCopy didn't panic when it should have") - } - - if !testCopy(a, b) { - t.Fatalf("testCopy didn't panic when it should have") - } -} - -func TestSigbusOnMemmove(t *testing.T) { - // Test that SIGBUS received by runtime.memmove when *not* doing - // CopyIn or CopyOut work gets propagated to the runtime. - const bufLen = pageSize - f, err := ioutil.TempFile("", "sigbus_test") - if err != nil { - t.Fatalf("TempFile failed: %v", err) - } - os.Remove(f.Name()) - defer f.Close() - - a, err := syscall.Mmap(int(f.Fd()), 0, bufLen, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED) - if err != nil { - t.Fatalf("Mmap failed: %v", err) - - } - defer syscall.Munmap(a) - b := randBuf(bufLen) - - if !testCopy(b, a) { - t.Fatalf("testCopy didn't panic when it should have") - } - - if !testCopy(a, b) { - t.Fatalf("testCopy didn't panic when it should have") - } -} diff --git a/pkg/sentry/platform/safecopy/safecopy_unsafe.go b/pkg/sentry/platform/safecopy/safecopy_unsafe.go deleted file mode 100644 index eef028e68..000000000 --- a/pkg/sentry/platform/safecopy/safecopy_unsafe.go +++ /dev/null @@ -1,335 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package safecopy - -import ( - "fmt" - "syscall" - "unsafe" -) - -// maxRegisterSize is the maximum register size used in memcpy and memclr. It -// is used to decide by how much to rewind the copy (for memcpy) or zeroing -// (for memclr) before proceeding. -const maxRegisterSize = 16 - -// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received -// during the copy, it returns the address that caused the fault and the number -// of the signal that was received. Otherwise, it returns an unspecified address -// and a signal number of 0. -// -// Data is copied in order, such that if a fault happens at address p, it is -// safe to assume that all data before p-maxRegisterSize has already been -// successfully copied. -// -//go:noescape -func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) - -// memclr sets the n bytes following ptr to zeroes. If a SIGSEGV or SIGBUS -// signal is received during the write, it returns the address that caused the -// fault and the number of the signal that was received. Otherwise, it returns -// an unspecified address and a signal number of 0. -// -// Data is written in order, such that if a fault happens at address p, it is -// safe to assume that all data before p-maxRegisterSize has already been -// successfully written. -// -//go:noescape -func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32) - -// swapUint32 atomically stores new into *ptr and returns (the previous *ptr -// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the -// value of old is unspecified, and sig is the number of the signal that was -// received. -// -// Preconditions: ptr must be aligned to a 4-byte boundary. -// -//go:noescape -func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32) - -// swapUint64 atomically stores new into *ptr and returns (the previous *ptr -// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the -// value of old is unspecified, and sig is the number of the signal that was -// received. -// -// Preconditions: ptr must be aligned to a 8-byte boundary. -// -//go:noescape -func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32) - -// compareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns -// (the value previously stored at ptr, 0). If a SIGSEGV or SIGBUS signal is -// received during the operation, the value of prev is unspecified, and sig is -// the number of the signal that was received. -// -// Preconditions: ptr must be aligned to a 4-byte boundary. -// -//go:noescape -func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32) - -// LoadUint32 is like sync/atomic.LoadUint32, but operates with user memory. It -// may fail with SIGSEGV or SIGBUS if it is received while reading from ptr. -// -// Preconditions: ptr must be aligned to a 4-byte boundary. -// -//go:noescape -func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32) - -// CopyIn copies len(dst) bytes from src to dst. It returns the number of bytes -// copied and an error if SIGSEGV or SIGBUS is received while reading from src. -func CopyIn(dst []byte, src unsafe.Pointer) (int, error) { - toCopy := uintptr(len(dst)) - if len(dst) == 0 { - return 0, nil - } - - fault, sig := memcpy(unsafe.Pointer(&dst[0]), src, toCopy) - if sig == 0 { - return len(dst), nil - } - - faultN, srcN := uintptr(fault), uintptr(src) - if faultN < srcN || faultN >= srcN+toCopy { - panic(fmt.Sprintf("CopyIn raised signal %d at %#x, which is outside source [%#x, %#x)", sig, faultN, srcN, srcN+toCopy)) - } - - // memcpy might have ended the copy up to maxRegisterSize bytes before - // fault, if an instruction caused a memory access that straddled two - // pages, and the second one faulted. Try to copy up to the fault. - var done int - if faultN-srcN > maxRegisterSize { - done = int(faultN - srcN - maxRegisterSize) - } - n, err := CopyIn(dst[done:int(faultN-srcN)], unsafe.Pointer(srcN+uintptr(done))) - done += n - if err != nil { - return done, err - } - return done, errorFromFaultSignal(fault, sig) -} - -// CopyOut copies len(src) bytes from src to dst. If returns the number of -// bytes done and an error if SIGSEGV or SIGBUS is received while writing to -// dst. -func CopyOut(dst unsafe.Pointer, src []byte) (int, error) { - toCopy := uintptr(len(src)) - if toCopy == 0 { - return 0, nil - } - - fault, sig := memcpy(dst, unsafe.Pointer(&src[0]), toCopy) - if sig == 0 { - return len(src), nil - } - - faultN, dstN := uintptr(fault), uintptr(dst) - if faultN < dstN || faultN >= dstN+toCopy { - panic(fmt.Sprintf("CopyOut raised signal %d at %#x, which is outside destination [%#x, %#x)", sig, faultN, dstN, dstN+toCopy)) - } - - // memcpy might have ended the copy up to maxRegisterSize bytes before - // fault, if an instruction caused a memory access that straddled two - // pages, and the second one faulted. Try to copy up to the fault. - var done int - if faultN-dstN > maxRegisterSize { - done = int(faultN - dstN - maxRegisterSize) - } - n, err := CopyOut(unsafe.Pointer(dstN+uintptr(done)), src[done:int(faultN-dstN)]) - done += n - if err != nil { - return done, err - } - return done, errorFromFaultSignal(fault, sig) -} - -// Copy copies toCopy bytes from src to dst. It returns the number of bytes -// copied and an error if SIGSEGV or SIGBUS is received while reading from src -// or writing to dst. -// -// Data is copied in order; if [src, src+toCopy) and [dst, dst+toCopy) overlap, -// the resulting contents of dst are unspecified. -func Copy(dst, src unsafe.Pointer, toCopy uintptr) (uintptr, error) { - if toCopy == 0 { - return 0, nil - } - - fault, sig := memcpy(dst, src, toCopy) - if sig == 0 { - return toCopy, nil - } - - // Did the fault occur while reading from src or writing to dst? - faultN, srcN, dstN := uintptr(fault), uintptr(src), uintptr(dst) - faultAfterSrc := ^uintptr(0) - if faultN >= srcN { - faultAfterSrc = faultN - srcN - } - faultAfterDst := ^uintptr(0) - if faultN >= dstN { - faultAfterDst = faultN - dstN - } - if faultAfterSrc >= toCopy && faultAfterDst >= toCopy { - panic(fmt.Sprintf("Copy raised signal %d at %#x, which is outside source [%#x, %#x) and destination [%#x, %#x)", sig, faultN, srcN, srcN+toCopy, dstN, dstN+toCopy)) - } - faultedAfter := faultAfterSrc - if faultedAfter > faultAfterDst { - faultedAfter = faultAfterDst - } - - // memcpy might have ended the copy up to maxRegisterSize bytes before - // fault, if an instruction caused a memory access that straddled two - // pages, and the second one faulted. Try to copy up to the fault. - var done uintptr - if faultedAfter > maxRegisterSize { - done = faultedAfter - maxRegisterSize - } - n, err := Copy(unsafe.Pointer(dstN+done), unsafe.Pointer(srcN+done), faultedAfter-done) - done += n - if err != nil { - return done, err - } - return done, errorFromFaultSignal(fault, sig) -} - -// ZeroOut writes toZero zero bytes to dst. It returns the number of bytes -// written and an error if SIGSEGV or SIGBUS is received while writing to dst. -func ZeroOut(dst unsafe.Pointer, toZero uintptr) (uintptr, error) { - if toZero == 0 { - return 0, nil - } - - fault, sig := memclr(dst, toZero) - if sig == 0 { - return toZero, nil - } - - faultN, dstN := uintptr(fault), uintptr(dst) - if faultN < dstN || faultN >= dstN+toZero { - panic(fmt.Sprintf("ZeroOut raised signal %d at %#x, which is outside destination [%#x, %#x)", sig, faultN, dstN, dstN+toZero)) - } - - // memclr might have ended the write up to maxRegisterSize bytes before - // fault, if an instruction caused a memory access that straddled two - // pages, and the second one faulted. Try to write up to the fault. - var done uintptr - if faultN-dstN > maxRegisterSize { - done = faultN - dstN - maxRegisterSize - } - n, err := ZeroOut(unsafe.Pointer(dstN+done), faultN-dstN-done) - done += n - if err != nil { - return done, err - } - return done, errorFromFaultSignal(fault, sig) -} - -// SwapUint32 is equivalent to sync/atomic.SwapUint32, except that it returns -// an error if SIGSEGV or SIGBUS is received while accessing ptr, or if ptr is -// not aligned to a 4-byte boundary. -func SwapUint32(ptr unsafe.Pointer, new uint32) (uint32, error) { - if addr := uintptr(ptr); addr&3 != 0 { - return 0, AlignmentError{addr, 4} - } - old, sig := swapUint32(ptr, new) - return old, errorFromFaultSignal(ptr, sig) -} - -// SwapUint64 is equivalent to sync/atomic.SwapUint64, except that it returns -// an error if SIGSEGV or SIGBUS is received while accessing ptr, or if ptr is -// not aligned to an 8-byte boundary. -func SwapUint64(ptr unsafe.Pointer, new uint64) (uint64, error) { - if addr := uintptr(ptr); addr&7 != 0 { - return 0, AlignmentError{addr, 8} - } - old, sig := swapUint64(ptr, new) - return old, errorFromFaultSignal(ptr, sig) -} - -// CompareAndSwapUint32 is equivalent to atomicbitops.CompareAndSwapUint32, -// except that it returns an error if SIGSEGV or SIGBUS is received while -// accessing ptr, or if ptr is not aligned to a 4-byte boundary. -func CompareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (uint32, error) { - if addr := uintptr(ptr); addr&3 != 0 { - return 0, AlignmentError{addr, 4} - } - prev, sig := compareAndSwapUint32(ptr, old, new) - return prev, errorFromFaultSignal(ptr, sig) -} - -// LoadUint32 is like sync/atomic.LoadUint32, but operates with user memory. It -// may fail with SIGSEGV or SIGBUS if it is received while reading from ptr. -// -// Preconditions: ptr must be aligned to a 4-byte boundary. -func LoadUint32(ptr unsafe.Pointer) (uint32, error) { - if addr := uintptr(ptr); addr&3 != 0 { - return 0, AlignmentError{addr, 4} - } - val, sig := loadUint32(ptr) - return val, errorFromFaultSignal(ptr, sig) -} - -func errorFromFaultSignal(addr unsafe.Pointer, sig int32) error { - switch sig { - case 0: - return nil - case int32(syscall.SIGSEGV): - return SegvError{uintptr(addr)} - case int32(syscall.SIGBUS): - return BusError{uintptr(addr)} - default: - panic(fmt.Sprintf("safecopy got unexpected signal %d at address %#x", sig, addr)) - } -} - -// ReplaceSignalHandler replaces the existing signal handler for the provided -// signal with the one that handles faults in safecopy-protected functions. -// -// It stores the value of the previously set handler in previous. -// -// This function will be called on initialization in order to install safecopy -// handlers for appropriate signals. These handlers will call the previous -// handler however, and if this is function is being used externally then the -// same courtesy is expected. -func ReplaceSignalHandler(sig syscall.Signal, handler uintptr, previous *uintptr) error { - var sa struct { - handler uintptr - flags uint64 - restorer uintptr - mask uint64 - } - const maskLen = 8 - - // Get the existing signal handler information, and save the current - // handler. Once we replace it, we will use this pointer to fall back to - // it when we receive other signals. - if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 { - return e - } - - // Fail if there isn't a previous handler. - if sa.handler == 0 { - return fmt.Errorf("previous handler for signal %x isn't set", sig) - } - - *previous = sa.handler - - // Install our own handler. - sa.handler = handler - if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 { - return e - } - - return nil -} diff --git a/pkg/sentry/platform/safecopy/sighandler_amd64.s b/pkg/sentry/platform/safecopy/sighandler_amd64.s deleted file mode 100644 index 475ae48e9..000000000 --- a/pkg/sentry/platform/safecopy/sighandler_amd64.s +++ /dev/null @@ -1,133 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -#include "textflag.h" - -// The signals handled by sigHandler. -#define SIGBUS 7 -#define SIGSEGV 11 - -// Offsets to the registers in context->uc_mcontext.gregs[]. -#define REG_RDI 0x68 -#define REG_RAX 0x90 -#define REG_IP 0xa8 - -// Offset to the si_addr field of siginfo. -#define SI_CODE 0x08 -#define SI_ADDR 0x10 - -// signalHandler is the signal handler for SIGSEGV and SIGBUS signals. It must -// not be set up as a handler to any other signals. -// -// If the instruction causing the signal is within a safecopy-protected -// function, the signal is handled such that execution resumes in the -// appropriate fault handling stub with AX containing the faulting address and -// DI containing the signal number. Otherwise control is transferred to the -// previously configured signal handler (savedSigSegvHandler or -// savedSigBusHandler). -// -// This function cannot be written in go because it runs whenever a signal is -// received by the thread (preempting whatever was running), which includes when -// garbage collector has stopped or isn't expecting any interactions (like -// barriers). -// -// The arguments are the following: -// DI - The signal number. -// SI - Pointer to siginfo_t structure. -// DX - Pointer to ucontext structure. -TEXT ·signalHandler(SB),NOSPLIT,$0 - // Check if the signal is from the kernel. - MOVQ $0x0, CX - CMPL CX, SI_CODE(SI) - JGE original_handler - - // Check if RIP is within the area we care about. - MOVQ REG_IP(DX), CX - CMPQ CX, ·memcpyBegin(SB) - JB not_memcpy - CMPQ CX, ·memcpyEnd(SB) - JAE not_memcpy - - // Modify the context such that execution will resume in the fault - // handler. - LEAQ handleMemcpyFault(SB), CX - JMP handle_fault - -not_memcpy: - CMPQ CX, ·memclrBegin(SB) - JB not_memclr - CMPQ CX, ·memclrEnd(SB) - JAE not_memclr - - LEAQ handleMemclrFault(SB), CX - JMP handle_fault - -not_memclr: - CMPQ CX, ·swapUint32Begin(SB) - JB not_swapuint32 - CMPQ CX, ·swapUint32End(SB) - JAE not_swapuint32 - - LEAQ handleSwapUint32Fault(SB), CX - JMP handle_fault - -not_swapuint32: - CMPQ CX, ·swapUint64Begin(SB) - JB not_swapuint64 - CMPQ CX, ·swapUint64End(SB) - JAE not_swapuint64 - - LEAQ handleSwapUint64Fault(SB), CX - JMP handle_fault - -not_swapuint64: - CMPQ CX, ·compareAndSwapUint32Begin(SB) - JB not_casuint32 - CMPQ CX, ·compareAndSwapUint32End(SB) - JAE not_casuint32 - - LEAQ handleCompareAndSwapUint32Fault(SB), CX - JMP handle_fault - -not_casuint32: - CMPQ CX, ·loadUint32Begin(SB) - JB not_loaduint32 - CMPQ CX, ·loadUint32End(SB) - JAE not_loaduint32 - - LEAQ handleLoadUint32Fault(SB), CX - JMP handle_fault - -not_loaduint32: -original_handler: - // Jump to the previous signal handler, which is likely the golang one. - XORQ CX, CX - MOVQ ·savedSigBusHandler(SB), AX - CMPL DI, $SIGSEGV - CMOVQEQ ·savedSigSegVHandler(SB), AX - JMP AX - -handle_fault: - // Entered with the address of the fault handler in RCX; store it in - // RIP. - MOVQ CX, REG_IP(DX) - - // Store the faulting address in RAX. - MOVQ SI_ADDR(SI), CX - MOVQ CX, REG_RAX(DX) - - // Store the signal number in EDI. - MOVL DI, REG_RDI(DX) - - RET diff --git a/pkg/sentry/platform/safecopy/sighandler_arm64.s b/pkg/sentry/platform/safecopy/sighandler_arm64.s deleted file mode 100644 index 53e4ac2c1..000000000 --- a/pkg/sentry/platform/safecopy/sighandler_arm64.s +++ /dev/null @@ -1,143 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -#include "textflag.h" - -// The signals handled by sigHandler. -#define SIGBUS 7 -#define SIGSEGV 11 - -// Offsets to the registers in context->uc_mcontext.gregs[]. -#define REG_R0 0xB8 -#define REG_R1 0xC0 -#define REG_PC 0x1B8 - -// Offset to the si_addr field of siginfo. -#define SI_CODE 0x08 -#define SI_ADDR 0x10 - -// signalHandler is the signal handler for SIGSEGV and SIGBUS signals. It must -// not be set up as a handler to any other signals. -// -// If the instruction causing the signal is within a safecopy-protected -// function, the signal is handled such that execution resumes in the -// appropriate fault handling stub with R0 containing the faulting address and -// R1 containing the signal number. Otherwise control is transferred to the -// previously configured signal handler (savedSigSegvHandler or -// savedSigBusHandler). -// -// This function cannot be written in go because it runs whenever a signal is -// received by the thread (preempting whatever was running), which includes when -// garbage collector has stopped or isn't expecting any interactions (like -// barriers). -// -// The arguments are the following: -// R0 - The signal number. -// R1 - Pointer to siginfo_t structure. -// R2 - Pointer to ucontext structure. -TEXT ·signalHandler(SB),NOSPLIT,$0 - // Check if the signal is from the kernel, si_code > 0 means a kernel signal. - MOVD SI_CODE(R1), R7 - CMPW $0x0, R7 - BLE original_handler - - // Check if PC is within the area we care about. - MOVD REG_PC(R2), R7 - MOVD ·memcpyBegin(SB), R8 - CMP R8, R7 - BLO not_memcpy - MOVD ·memcpyEnd(SB), R8 - CMP R8, R7 - BHS not_memcpy - - // Modify the context such that execution will resume in the fault handler. - MOVD $handleMemcpyFault(SB), R7 - B handle_fault - -not_memcpy: - MOVD ·memclrBegin(SB), R8 - CMP R8, R7 - BLO not_memclr - MOVD ·memclrEnd(SB), R8 - CMP R8, R7 - BHS not_memclr - - MOVD $handleMemclrFault(SB), R7 - B handle_fault - -not_memclr: - MOVD ·swapUint32Begin(SB), R8 - CMP R8, R7 - BLO not_swapuint32 - MOVD ·swapUint32End(SB), R8 - CMP R8, R7 - BHS not_swapuint32 - - MOVD $handleSwapUint32Fault(SB), R7 - B handle_fault - -not_swapuint32: - MOVD ·swapUint64Begin(SB), R8 - CMP R8, R7 - BLO not_swapuint64 - MOVD ·swapUint64End(SB), R8 - CMP R8, R7 - BHS not_swapuint64 - - MOVD $handleSwapUint64Fault(SB), R7 - B handle_fault - -not_swapuint64: - MOVD ·compareAndSwapUint32Begin(SB), R8 - CMP R8, R7 - BLO not_casuint32 - MOVD ·compareAndSwapUint32End(SB), R8 - CMP R8, R7 - BHS not_casuint32 - - MOVD $handleCompareAndSwapUint32Fault(SB), R7 - B handle_fault - -not_casuint32: - MOVD ·loadUint32Begin(SB), R8 - CMP R8, R7 - BLO not_loaduint32 - MOVD ·loadUint32End(SB), R8 - CMP R8, R7 - BHS not_loaduint32 - - MOVD $handleLoadUint32Fault(SB), R7 - B handle_fault - -not_loaduint32: -original_handler: - // Jump to the previous signal handler, which is likely the golang one. - MOVD ·savedSigBusHandler(SB), R7 - MOVD ·savedSigSegVHandler(SB), R8 - CMPW $SIGSEGV, R0 - CSEL EQ, R8, R7, R7 - B (R7) - -handle_fault: - // Entered with the address of the fault handler in R7; store it in PC. - MOVD R7, REG_PC(R2) - - // Store the faulting address in R0. - MOVD SI_ADDR(R1), R7 - MOVD R7, REG_R0(R2) - - // Store the signal number in R1. - MOVW R0, REG_R1(R2) - - RET |