diff options
Diffstat (limited to 'pkg/sentry/usermem')
| -rw-r--r-- | pkg/sentry/usermem/access_type.go | 128 | ||||
| -rw-r--r-- | pkg/sentry/usermem/addr.go | 108 | ||||
| -rwxr-xr-x | pkg/sentry/usermem/addr_range.go | 62 | ||||
| -rw-r--r-- | pkg/sentry/usermem/addr_range_seq_unsafe.go | 277 | ||||
| -rw-r--r-- | pkg/sentry/usermem/bytes_io.go | 126 | ||||
| -rw-r--r-- | pkg/sentry/usermem/bytes_io_unsafe.go | 47 | ||||
| -rw-r--r-- | pkg/sentry/usermem/usermem.go | 587 | ||||
| -rw-r--r-- | pkg/sentry/usermem/usermem_arm64.go | 53 | ||||
| -rwxr-xr-x | pkg/sentry/usermem/usermem_state_autogen.go | 49 | ||||
| -rw-r--r-- | pkg/sentry/usermem/usermem_unsafe.go | 27 | ||||
| -rw-r--r-- | pkg/sentry/usermem/usermem_x86.go | 38 |
11 files changed, 1502 insertions, 0 deletions
diff --git a/pkg/sentry/usermem/access_type.go b/pkg/sentry/usermem/access_type.go new file mode 100644 index 000000000..9c1742a59 --- /dev/null +++ b/pkg/sentry/usermem/access_type.go @@ -0,0 +1,128 @@ +// 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 usermem + +import ( + "syscall" +) + +// AccessType specifies memory access types. This is used for +// setting mapping permissions, as well as communicating faults. +// +// +stateify savable +type AccessType struct { + // Read is read access. + Read bool + + // Write is write access. + Write bool + + // Execute is executable access. + Execute bool +} + +// String returns a pretty representation of access. This looks like the +// familiar r-x, rw-, etc. and can be relied on as such. +func (a AccessType) String() string { + bits := [3]byte{'-', '-', '-'} + if a.Read { + bits[0] = 'r' + } + if a.Write { + bits[1] = 'w' + } + if a.Execute { + bits[2] = 'x' + } + return string(bits[:]) +} + +// Any returns true iff at least one of Read, Write or Execute is true. +func (a AccessType) Any() bool { + return a.Read || a.Write || a.Execute +} + +// Prot returns the system prot (syscall.PROT_READ, etc.) for this access. +func (a AccessType) Prot() int { + var prot int + if a.Read { + prot |= syscall.PROT_READ + } + if a.Write { + prot |= syscall.PROT_WRITE + } + if a.Execute { + prot |= syscall.PROT_EXEC + } + return prot +} + +// SupersetOf returns true iff the access types in a are a superset of the +// access types in other. +func (a AccessType) SupersetOf(other AccessType) bool { + if !a.Read && other.Read { + return false + } + if !a.Write && other.Write { + return false + } + if !a.Execute && other.Execute { + return false + } + return true +} + +// Intersect returns the access types set in both a and other. +func (a AccessType) Intersect(other AccessType) AccessType { + return AccessType{ + Read: a.Read && other.Read, + Write: a.Write && other.Write, + Execute: a.Execute && other.Execute, + } +} + +// Union returns the access types set in either a or other. +func (a AccessType) Union(other AccessType) AccessType { + return AccessType{ + Read: a.Read || other.Read, + Write: a.Write || other.Write, + Execute: a.Execute || other.Execute, + } +} + +// Effective returns the set of effective access types allowed by a, even if +// some types are not explicitly allowed. +func (a AccessType) Effective() AccessType { + // In Linux, Write and Execute access generally imply Read access. See + // mm/mmap.c:protection_map. + // + // The notable exception is get_user_pages, which only checks against + // the original vma flags. That said, most user memory accesses do not + // use GUP. + if a.Write || a.Execute { + a.Read = true + } + return a +} + +// Convenient access types. +var ( + NoAccess = AccessType{} + Read = AccessType{Read: true} + Write = AccessType{Write: true} + Execute = AccessType{Execute: true} + ReadWrite = AccessType{Read: true, Write: true} + AnyAccess = AccessType{Read: true, Write: true, Execute: true} +) diff --git a/pkg/sentry/usermem/addr.go b/pkg/sentry/usermem/addr.go new file mode 100644 index 000000000..e79210804 --- /dev/null +++ b/pkg/sentry/usermem/addr.go @@ -0,0 +1,108 @@ +// 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 usermem + +import ( + "fmt" +) + +// Addr represents a generic virtual address. +// +// +stateify savable +type Addr uintptr + +// AddLength adds the given length to start and returns the result. ok is true +// iff adding the length did not overflow the range of Addr. +// +// Note: This function is usually used to get the end of an address range +// defined by its start address and length. Since the resulting end is +// exclusive, end == 0 is technically valid, and corresponds to a range that +// extends to the end of the address space, but ok will be false. This isn't +// expected to ever come up in practice. +func (v Addr) AddLength(length uint64) (end Addr, ok bool) { + end = v + Addr(length) + // The second half of the following check is needed in case uintptr is + // smaller than 64 bits. + ok = end >= v && length <= uint64(^Addr(0)) + return +} + +// RoundDown returns the address rounded down to the nearest page boundary. +func (v Addr) RoundDown() Addr { + return v & ^Addr(PageSize-1) +} + +// RoundUp returns the address rounded up to the nearest page boundary. ok is +// true iff rounding up did not wrap around. +func (v Addr) RoundUp() (addr Addr, ok bool) { + addr = Addr(v + PageSize - 1).RoundDown() + ok = addr >= v + return +} + +// MustRoundUp is equivalent to RoundUp, but panics if rounding up wraps +// around. +func (v Addr) MustRoundUp() Addr { + addr, ok := v.RoundUp() + if !ok { + panic(fmt.Sprintf("usermem.Addr(%d).RoundUp() wraps", v)) + } + return addr +} + +// HugeRoundDown returns the address rounded down to the nearest huge page +// boundary. +func (v Addr) HugeRoundDown() Addr { + return v & ^Addr(HugePageSize-1) +} + +// HugeRoundUp returns the address rounded up to the nearest huge page boundary. +// ok is true iff rounding up did not wrap around. +func (v Addr) HugeRoundUp() (addr Addr, ok bool) { + addr = Addr(v + HugePageSize - 1).HugeRoundDown() + ok = addr >= v + return +} + +// PageOffset returns the offset of v into the current page. +func (v Addr) PageOffset() uint64 { + return uint64(v & Addr(PageSize-1)) +} + +// IsPageAligned returns true if v.PageOffset() == 0. +func (v Addr) IsPageAligned() bool { + return v.PageOffset() == 0 +} + +// AddrRange is a range of Addrs. +// +// type AddrRange <generated by go_generics> + +// ToRange returns [v, v+length). +func (v Addr) ToRange(length uint64) (AddrRange, bool) { + end, ok := v.AddLength(length) + return AddrRange{v, end}, ok +} + +// IsPageAligned returns true if ar.Start.IsPageAligned() and +// ar.End.IsPageAligned(). +func (ar AddrRange) IsPageAligned() bool { + return ar.Start.IsPageAligned() && ar.End.IsPageAligned() +} + +// String implements fmt.Stringer.String. +func (ar AddrRange) String() string { + return fmt.Sprintf("[%#x, %#x)", ar.Start, ar.End) +} diff --git a/pkg/sentry/usermem/addr_range.go b/pkg/sentry/usermem/addr_range.go new file mode 100755 index 000000000..152ed1434 --- /dev/null +++ b/pkg/sentry/usermem/addr_range.go @@ -0,0 +1,62 @@ +package usermem + +// A Range represents a contiguous range of T. +// +// +stateify savable +type AddrRange struct { + // Start is the inclusive start of the range. + Start Addr + + // End is the exclusive end of the range. + End Addr +} + +// WellFormed returns true if r.Start <= r.End. All other methods on a Range +// require that the Range is well-formed. +func (r AddrRange) WellFormed() bool { + return r.Start <= r.End +} + +// Length returns the length of the range. +func (r AddrRange) Length() Addr { + return r.End - r.Start +} + +// Contains returns true if r contains x. +func (r AddrRange) Contains(x Addr) bool { + return r.Start <= x && x < r.End +} + +// Overlaps returns true if r and r2 overlap. +func (r AddrRange) Overlaps(r2 AddrRange) bool { + return r.Start < r2.End && r2.Start < r.End +} + +// IsSupersetOf returns true if r is a superset of r2; that is, the range r2 is +// contained within r. +func (r AddrRange) IsSupersetOf(r2 AddrRange) bool { + return r.Start <= r2.Start && r.End >= r2.End +} + +// Intersect returns a range consisting of the intersection between r and r2. +// If r and r2 do not overlap, Intersect returns a range with unspecified +// bounds, but for which Length() == 0. +func (r AddrRange) Intersect(r2 AddrRange) AddrRange { + if r.Start < r2.Start { + r.Start = r2.Start + } + if r.End > r2.End { + r.End = r2.End + } + if r.End < r.Start { + r.End = r.Start + } + return r +} + +// CanSplitAt returns true if it is legal to split a segment spanning the range +// r at x; that is, splitting at x would produce two ranges, both of which have +// non-zero length. +func (r AddrRange) CanSplitAt(x Addr) bool { + return r.Contains(x) && r.Start < x +} diff --git a/pkg/sentry/usermem/addr_range_seq_unsafe.go b/pkg/sentry/usermem/addr_range_seq_unsafe.go new file mode 100644 index 000000000..c09337c15 --- /dev/null +++ b/pkg/sentry/usermem/addr_range_seq_unsafe.go @@ -0,0 +1,277 @@ +// 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 usermem + +import ( + "bytes" + "fmt" + "reflect" + "unsafe" +) + +// An AddrRangeSeq represents a sequence of AddrRanges. +// +// AddrRangeSeqs are immutable and may be copied by value. The zero value of +// AddrRangeSeq represents an empty sequence. +// +// An AddrRangeSeq may contain AddrRanges with a length of 0. This is necessary +// since zero-length AddrRanges are significant to MM bounds checks. +type AddrRangeSeq struct { + // If length is 0, then the AddrRangeSeq represents no AddrRanges. + // Invariants: data == 0; offset == 0; limit == 0. + // + // If length is 1, then the AddrRangeSeq represents the single + // AddrRange{offset, offset+limit}. Invariants: data == 0. + // + // Otherwise, length >= 2, and the AddrRangeSeq represents the `length` + // AddrRanges in the array of AddrRanges starting at address `data`, + // starting at `offset` bytes into the first AddrRange and limited to the + // following `limit` bytes. (AddrRanges after `limit` are still iterated, + // but are truncated to a length of 0.) Invariants: data != 0; offset <= + // data[0].Length(); limit > 0; offset+limit <= the combined length of all + // AddrRanges in the array. + data unsafe.Pointer + length int + offset Addr + limit Addr +} + +// AddrRangeSeqOf returns an AddrRangeSeq representing the single AddrRange ar. +func AddrRangeSeqOf(ar AddrRange) AddrRangeSeq { + return AddrRangeSeq{ + length: 1, + offset: ar.Start, + limit: ar.Length(), + } +} + +// AddrRangeSeqFromSlice returns an AddrRangeSeq representing all AddrRanges in +// slice. +// +// Whether the returned AddrRangeSeq shares memory with slice is unspecified; +// clients should avoid mutating slices passed to AddrRangeSeqFromSlice. +// +// Preconditions: The combined length of all AddrRanges in slice <= +// math.MaxInt64. +func AddrRangeSeqFromSlice(slice []AddrRange) AddrRangeSeq { + var limit int64 + for _, ar := range slice { + len64 := int64(ar.Length()) + if len64 < 0 { + panic(fmt.Sprintf("Length of AddrRange %v overflows int64", ar)) + } + sum := limit + len64 + if sum < limit { + panic(fmt.Sprintf("Total length of AddrRanges %v overflows int64", slice)) + } + limit = sum + } + return addrRangeSeqFromSliceLimited(slice, limit) +} + +// Preconditions: The combined length of all AddrRanges in slice <= limit. +// limit >= 0. If len(slice) != 0, then limit > 0. +func addrRangeSeqFromSliceLimited(slice []AddrRange, limit int64) AddrRangeSeq { + switch len(slice) { + case 0: + return AddrRangeSeq{} + case 1: + return AddrRangeSeq{ + length: 1, + offset: slice[0].Start, + limit: Addr(limit), + } + default: + return AddrRangeSeq{ + data: unsafe.Pointer(&slice[0]), + length: len(slice), + limit: Addr(limit), + } + } +} + +// IsEmpty returns true if ars.NumRanges() == 0. +// +// Note that since AddrRangeSeq may contain AddrRanges with a length of zero, +// an AddrRange representing 0 bytes (AddrRangeSeq.NumBytes() == 0) is not +// necessarily empty. +func (ars AddrRangeSeq) IsEmpty() bool { + return ars.length == 0 +} + +// NumRanges returns the number of AddrRanges in ars. +func (ars AddrRangeSeq) NumRanges() int { + return ars.length +} + +// NumBytes returns the number of bytes represented by ars. +func (ars AddrRangeSeq) NumBytes() int64 { + return int64(ars.limit) +} + +// Head returns the first AddrRange in ars. +// +// Preconditions: !ars.IsEmpty(). +func (ars AddrRangeSeq) Head() AddrRange { + if ars.length == 0 { + panic("empty AddrRangeSeq") + } + if ars.length == 1 { + return AddrRange{ars.offset, ars.offset + ars.limit} + } + ar := *(*AddrRange)(ars.data) + ar.Start += ars.offset + if ar.Length() > ars.limit { + ar.End = ar.Start + ars.limit + } + return ar +} + +// Tail returns an AddrRangeSeq consisting of all AddrRanges in ars after the +// first. +// +// Preconditions: !ars.IsEmpty(). +func (ars AddrRangeSeq) Tail() AddrRangeSeq { + if ars.length == 0 { + panic("empty AddrRangeSeq") + } + if ars.length == 1 { + return AddrRangeSeq{} + } + return ars.externalTail() +} + +// Preconditions: ars.length >= 2. +func (ars AddrRangeSeq) externalTail() AddrRangeSeq { + headLen := (*AddrRange)(ars.data).Length() - ars.offset + var tailLimit int64 + if ars.limit > headLen { + tailLimit = int64(ars.limit - headLen) + } + var extSlice []AddrRange + extSliceHdr := (*reflect.SliceHeader)(unsafe.Pointer(&extSlice)) + extSliceHdr.Data = uintptr(ars.data) + extSliceHdr.Len = ars.length + extSliceHdr.Cap = ars.length + return addrRangeSeqFromSliceLimited(extSlice[1:], tailLimit) +} + +// DropFirst returns an AddrRangeSeq equivalent to ars, but with the first n +// bytes omitted. If n > ars.NumBytes(), DropFirst returns an empty +// AddrRangeSeq. +// +// If !ars.IsEmpty() and ars.Head().Length() == 0, DropFirst will always omit +// at least ars.Head(), even if n == 0. This guarantees that the basic pattern +// of: +// +// for !ars.IsEmpty() { +// n, err = doIOWith(ars.Head()) +// if err != nil { +// return err +// } +// ars = ars.DropFirst(n) +// } +// +// works even in the presence of zero-length AddrRanges. +// +// Preconditions: n >= 0. +func (ars AddrRangeSeq) DropFirst(n int) AddrRangeSeq { + if n < 0 { + panic(fmt.Sprintf("invalid n: %d", n)) + } + return ars.DropFirst64(int64(n)) +} + +// DropFirst64 is equivalent to DropFirst but takes an int64. +func (ars AddrRangeSeq) DropFirst64(n int64) AddrRangeSeq { + if n < 0 { + panic(fmt.Sprintf("invalid n: %d", n)) + } + if Addr(n) > ars.limit { + return AddrRangeSeq{} + } + // Handle initial empty AddrRange. + switch ars.length { + case 0: + return AddrRangeSeq{} + case 1: + if ars.limit == 0 { + return AddrRangeSeq{} + } + default: + if rawHeadLen := (*AddrRange)(ars.data).Length(); ars.offset == rawHeadLen { + ars = ars.externalTail() + } + } + for n != 0 { + // Calling ars.Head() here is surprisingly expensive, so inline getting + // the head's length. + var headLen Addr + if ars.length == 1 { + headLen = ars.limit + } else { + headLen = (*AddrRange)(ars.data).Length() - ars.offset + } + if Addr(n) < headLen { + // Dropping ends partway through the head AddrRange. + ars.offset += Addr(n) + ars.limit -= Addr(n) + return ars + } + n -= int64(headLen) + ars = ars.Tail() + } + return ars +} + +// TakeFirst returns an AddrRangeSeq equivalent to ars, but iterating at most n +// bytes. TakeFirst never removes AddrRanges from ars; AddrRanges beyond the +// first n bytes are reduced to a length of zero, but will still be iterated. +// +// Preconditions: n >= 0. +func (ars AddrRangeSeq) TakeFirst(n int) AddrRangeSeq { + if n < 0 { + panic(fmt.Sprintf("invalid n: %d", n)) + } + return ars.TakeFirst64(int64(n)) +} + +// TakeFirst64 is equivalent to TakeFirst but takes an int64. +func (ars AddrRangeSeq) TakeFirst64(n int64) AddrRangeSeq { + if n < 0 { + panic(fmt.Sprintf("invalid n: %d", n)) + } + if ars.limit > Addr(n) { + ars.limit = Addr(n) + } + return ars +} + +// String implements fmt.Stringer.String. +func (ars AddrRangeSeq) String() string { + // This is deliberately chosen to be the same as fmt's automatic stringer + // for []AddrRange. + var buf bytes.Buffer + buf.WriteByte('[') + var sep string + for !ars.IsEmpty() { + buf.WriteString(sep) + sep = " " + buf.WriteString(ars.Head().String()) + ars = ars.Tail() + } + buf.WriteByte(']') + return buf.String() +} diff --git a/pkg/sentry/usermem/bytes_io.go b/pkg/sentry/usermem/bytes_io.go new file mode 100644 index 000000000..f98d82168 --- /dev/null +++ b/pkg/sentry/usermem/bytes_io.go @@ -0,0 +1,126 @@ +// 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 usermem + +import ( + "gvisor.googlesource.com/gvisor/pkg/sentry/context" + "gvisor.googlesource.com/gvisor/pkg/sentry/safemem" + "gvisor.googlesource.com/gvisor/pkg/syserror" +) + +const maxInt = int(^uint(0) >> 1) + +// BytesIO implements IO using a byte slice. Addresses are interpreted as +// offsets into the slice. Reads and writes beyond the end of the slice return +// EFAULT. +type BytesIO struct { + Bytes []byte +} + +// CopyOut implements IO.CopyOut. +func (b *BytesIO) CopyOut(ctx context.Context, addr Addr, src []byte, opts IOOpts) (int, error) { + rngN, rngErr := b.rangeCheck(addr, len(src)) + if rngN == 0 { + return 0, rngErr + } + return copy(b.Bytes[int(addr):], src[:rngN]), rngErr +} + +// CopyIn implements IO.CopyIn. +func (b *BytesIO) CopyIn(ctx context.Context, addr Addr, dst []byte, opts IOOpts) (int, error) { + rngN, rngErr := b.rangeCheck(addr, len(dst)) + if rngN == 0 { + return 0, rngErr + } + return copy(dst[:rngN], b.Bytes[int(addr):]), rngErr +} + +// ZeroOut implements IO.ZeroOut. +func (b *BytesIO) ZeroOut(ctx context.Context, addr Addr, toZero int64, opts IOOpts) (int64, error) { + if toZero > int64(maxInt) { + return 0, syserror.EINVAL + } + rngN, rngErr := b.rangeCheck(addr, int(toZero)) + if rngN == 0 { + return 0, rngErr + } + zeroSlice := b.Bytes[int(addr) : int(addr)+rngN] + for i := range zeroSlice { + zeroSlice[i] = 0 + } + return int64(rngN), rngErr +} + +// CopyOutFrom implements IO.CopyOutFrom. +func (b *BytesIO) CopyOutFrom(ctx context.Context, ars AddrRangeSeq, src safemem.Reader, opts IOOpts) (int64, error) { + dsts, rngErr := b.blocksFromAddrRanges(ars) + n, err := src.ReadToBlocks(dsts) + if err != nil { + return int64(n), err + } + return int64(n), rngErr +} + +// CopyInTo implements IO.CopyInTo. +func (b *BytesIO) CopyInTo(ctx context.Context, ars AddrRangeSeq, dst safemem.Writer, opts IOOpts) (int64, error) { + srcs, rngErr := b.blocksFromAddrRanges(ars) + n, err := dst.WriteFromBlocks(srcs) + if err != nil { + return int64(n), err + } + return int64(n), rngErr +} + +func (b *BytesIO) rangeCheck(addr Addr, length int) (int, error) { + if length == 0 { + return 0, nil + } + if length < 0 { + return 0, syserror.EINVAL + } + max := Addr(len(b.Bytes)) + if addr >= max { + return 0, syserror.EFAULT + } + end, ok := addr.AddLength(uint64(length)) + if !ok || end > max { + return int(max - addr), syserror.EFAULT + } + return length, nil +} + +func (b *BytesIO) blocksFromAddrRanges(ars AddrRangeSeq) (safemem.BlockSeq, error) { + blocks := make([]safemem.Block, 0, ars.NumRanges()) + for !ars.IsEmpty() { + ar := ars.Head() + n, err := b.rangeCheck(ar.Start, int(ar.Length())) + if n != 0 { + blocks = append(blocks, safemem.BlockFromSafeSlice(b.Bytes[int(ar.Start):int(ar.Start)+n])) + } + if err != nil { + return safemem.BlockSeqFromSlice(blocks), err + } + ars = ars.Tail() + } + return safemem.BlockSeqFromSlice(blocks), nil +} + +// BytesIOSequence returns an IOSequence representing the given byte slice. +func BytesIOSequence(buf []byte) IOSequence { + return IOSequence{ + IO: &BytesIO{buf}, + Addrs: AddrRangeSeqOf(AddrRange{0, Addr(len(buf))}), + } +} diff --git a/pkg/sentry/usermem/bytes_io_unsafe.go b/pkg/sentry/usermem/bytes_io_unsafe.go new file mode 100644 index 000000000..bb49d2ff3 --- /dev/null +++ b/pkg/sentry/usermem/bytes_io_unsafe.go @@ -0,0 +1,47 @@ +// 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 usermem + +import ( + "sync/atomic" + "unsafe" + + "gvisor.googlesource.com/gvisor/pkg/atomicbitops" + "gvisor.googlesource.com/gvisor/pkg/sentry/context" +) + +// SwapUint32 implements IO.SwapUint32. +func (b *BytesIO) SwapUint32(ctx context.Context, addr Addr, new uint32, opts IOOpts) (uint32, error) { + if _, rngErr := b.rangeCheck(addr, 4); rngErr != nil { + return 0, rngErr + } + return atomic.SwapUint32((*uint32)(unsafe.Pointer(&b.Bytes[int(addr)])), new), nil +} + +// CompareAndSwapUint32 implements IO.CompareAndSwapUint32. +func (b *BytesIO) CompareAndSwapUint32(ctx context.Context, addr Addr, old, new uint32, opts IOOpts) (uint32, error) { + if _, rngErr := b.rangeCheck(addr, 4); rngErr != nil { + return 0, rngErr + } + return atomicbitops.CompareAndSwapUint32((*uint32)(unsafe.Pointer(&b.Bytes[int(addr)])), old, new), nil +} + +// LoadUint32 implements IO.LoadUint32. +func (b *BytesIO) LoadUint32(ctx context.Context, addr Addr, opts IOOpts) (uint32, error) { + if _, err := b.rangeCheck(addr, 4); err != nil { + return 0, err + } + return atomic.LoadUint32((*uint32)(unsafe.Pointer(&b.Bytes[int(addr)]))), nil +} diff --git a/pkg/sentry/usermem/usermem.go b/pkg/sentry/usermem/usermem.go new file mode 100644 index 000000000..31e4d6ada --- /dev/null +++ b/pkg/sentry/usermem/usermem.go @@ -0,0 +1,587 @@ +// 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 usermem governs access to user memory. +package usermem + +import ( + "errors" + "io" + "strconv" + + "gvisor.googlesource.com/gvisor/pkg/binary" + "gvisor.googlesource.com/gvisor/pkg/sentry/context" + "gvisor.googlesource.com/gvisor/pkg/sentry/safemem" + "gvisor.googlesource.com/gvisor/pkg/syserror" +) + +// IO provides access to the contents of a virtual memory space. +// +// FIXME(b/38173783): Implementations of IO cannot expect ctx to contain any +// meaningful data. +type IO interface { + // CopyOut copies len(src) bytes from src to the memory mapped at addr. It + // returns the number of bytes copied. If the number of bytes copied is < + // len(src), it returns a non-nil error explaining why. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. + // + // Postconditions: CopyOut does not retain src. + CopyOut(ctx context.Context, addr Addr, src []byte, opts IOOpts) (int, error) + + // CopyIn copies len(dst) bytes from the memory mapped at addr to dst. + // It returns the number of bytes copied. If the number of bytes copied is + // < len(dst), it returns a non-nil error explaining why. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. + // + // Postconditions: CopyIn does not retain dst. + CopyIn(ctx context.Context, addr Addr, dst []byte, opts IOOpts) (int, error) + + // ZeroOut sets toZero bytes to 0, starting at addr. It returns the number + // of bytes zeroed. If the number of bytes zeroed is < toZero, it returns a + // non-nil error explaining why. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. toZero >= 0. + ZeroOut(ctx context.Context, addr Addr, toZero int64, opts IOOpts) (int64, error) + + // CopyOutFrom copies ars.NumBytes() bytes from src to the memory mapped at + // ars. It returns the number of bytes copied, which may be less than the + // number of bytes read from src if copying fails. CopyOutFrom may return a + // partial copy without an error iff src.ReadToBlocks returns a partial + // read without an error. + // + // CopyOutFrom calls src.ReadToBlocks at most once. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. src.ReadToBlocks must not block + // on mm.MemoryManager.activeMu or any preceding locks in the lock order. + CopyOutFrom(ctx context.Context, ars AddrRangeSeq, src safemem.Reader, opts IOOpts) (int64, error) + + // CopyInTo copies ars.NumBytes() bytes from the memory mapped at ars to + // dst. It returns the number of bytes copied. CopyInTo may return a + // partial copy without an error iff dst.WriteFromBlocks returns a partial + // write without an error. + // + // CopyInTo calls dst.WriteFromBlocks at most once. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. dst.WriteFromBlocks must not + // block on mm.MemoryManager.activeMu or any preceding locks in the lock + // order. + CopyInTo(ctx context.Context, ars AddrRangeSeq, dst safemem.Writer, opts IOOpts) (int64, error) + + // TODO(jamieliu): The requirement that CopyOutFrom/CopyInTo call src/dst + // at most once, which is unnecessary in most cases, forces implementations + // to gather safemem.Blocks into a single slice to pass to src/dst. Add + // CopyOutFromIter/CopyInToIter, which relaxes this restriction, to avoid + // this allocation. + + // SwapUint32 atomically sets the uint32 value at addr to new and + // returns the previous value. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. addr must be aligned to a 4-byte + // boundary. + SwapUint32(ctx context.Context, addr Addr, new uint32, opts IOOpts) (uint32, error) + + // CompareAndSwapUint32 atomically compares the uint32 value at addr to + // old; if they are equal, the value in memory is replaced by new. In + // either case, the previous value stored in memory is returned. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. addr must be aligned to a 4-byte + // boundary. + CompareAndSwapUint32(ctx context.Context, addr Addr, old, new uint32, opts IOOpts) (uint32, error) + + // LoadUint32 atomically loads the uint32 value at addr and returns it. + // + // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or + // any following locks in the lock order. addr must be aligned to a 4-byte + // boundary. + LoadUint32(ctx context.Context, addr Addr, opts IOOpts) (uint32, error) +} + +// IOOpts contains options applicable to all IO methods. +type IOOpts struct { + // If IgnorePermissions is true, application-defined memory protections set + // by mmap(2) or mprotect(2) will be ignored. (Memory protections required + // by the target of the mapping are never ignored.) + IgnorePermissions bool + + // If AddressSpaceActive is true, the IO implementation may assume that it + // has an active AddressSpace and can therefore use AddressSpace copying + // without performing activation. See mm/io.go for details. + AddressSpaceActive bool +} + +// IOReadWriter is an io.ReadWriter that reads from / writes to addresses +// starting at addr in IO. The preconditions that apply to IO.CopyIn and +// IO.CopyOut also apply to IOReadWriter.Read and IOReadWriter.Write +// respectively. +type IOReadWriter struct { + Ctx context.Context + IO IO + Addr Addr + Opts IOOpts +} + +// Read implements io.Reader.Read. +// +// Note that an address space does not have an "end of file", so Read can only +// return io.EOF if IO.CopyIn returns io.EOF. Attempts to read unmapped or +// unreadable memory, or beyond the end of the address space, should return +// EFAULT. +func (rw *IOReadWriter) Read(dst []byte) (int, error) { + n, err := rw.IO.CopyIn(rw.Ctx, rw.Addr, dst, rw.Opts) + end, ok := rw.Addr.AddLength(uint64(n)) + if ok { + rw.Addr = end + } else { + // Disallow wraparound. + rw.Addr = ^Addr(0) + if err != nil { + err = syserror.EFAULT + } + } + return n, err +} + +// Writer implements io.Writer.Write. +func (rw *IOReadWriter) Write(src []byte) (int, error) { + n, err := rw.IO.CopyOut(rw.Ctx, rw.Addr, src, rw.Opts) + end, ok := rw.Addr.AddLength(uint64(n)) + if ok { + rw.Addr = end + } else { + // Disallow wraparound. + rw.Addr = ^Addr(0) + if err != nil { + err = syserror.EFAULT + } + } + return n, err +} + +// CopyObjectOut copies a fixed-size value or slice of fixed-size values from +// src to the memory mapped at addr in uio. It returns the number of bytes +// copied. +// +// CopyObjectOut must use reflection to encode src; performance-sensitive +// clients should do encoding manually and use uio.CopyOut directly. +// +// Preconditions: As for IO.CopyOut. +func CopyObjectOut(ctx context.Context, uio IO, addr Addr, src interface{}, opts IOOpts) (int, error) { + w := &IOReadWriter{ + Ctx: ctx, + IO: uio, + Addr: addr, + Opts: opts, + } + // Allocate a byte slice the size of the object being marshaled. This + // adds an extra reflection call, but avoids needing to grow the slice + // during encoding, which can result in many heap-allocated slices. + b := make([]byte, 0, binary.Size(src)) + return w.Write(binary.Marshal(b, ByteOrder, src)) +} + +// CopyObjectIn copies a fixed-size value or slice of fixed-size values from +// the memory mapped at addr in uio to dst. It returns the number of bytes +// copied. +// +// CopyObjectIn must use reflection to decode dst; performance-sensitive +// clients should use uio.CopyIn directly and do decoding manually. +// +// Preconditions: As for IO.CopyIn. +func CopyObjectIn(ctx context.Context, uio IO, addr Addr, dst interface{}, opts IOOpts) (int, error) { + r := &IOReadWriter{ + Ctx: ctx, + IO: uio, + Addr: addr, + Opts: opts, + } + buf := make([]byte, binary.Size(dst)) + if _, err := io.ReadFull(r, buf); err != nil { + return 0, err + } + binary.Unmarshal(buf, ByteOrder, dst) + return int(r.Addr - addr), nil +} + +// copyStringIncrement is the maximum number of bytes that are copied from +// virtual memory at a time by CopyStringIn. +const copyStringIncrement = 64 + +// CopyStringIn copies a NUL-terminated string of unknown length from the +// memory mapped at addr in uio and returns it as a string (not including the +// trailing NUL). If the length of the string, including the terminating NUL, +// would exceed maxlen, CopyStringIn returns the string truncated to maxlen and +// ENAMETOOLONG. +// +// Preconditions: As for IO.CopyFromUser. maxlen >= 0. +func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpts) (string, error) { + buf := make([]byte, maxlen) + var done int + for done < maxlen { + start, ok := addr.AddLength(uint64(done)) + if !ok { + // Last page of kernel memory. The application can't use this + // anyway. + return stringFromImmutableBytes(buf[:done]), syserror.EFAULT + } + // Read up to copyStringIncrement bytes at a time. + readlen := copyStringIncrement + if readlen > maxlen-done { + readlen = maxlen - done + } + end, ok := start.AddLength(uint64(readlen)) + if !ok { + return stringFromImmutableBytes(buf[:done]), syserror.EFAULT + } + // Shorten the read to avoid crossing page boundaries, since faulting + // in a page unnecessarily is expensive. This also ensures that partial + // copies up to the end of application-mappable memory succeed. + if start.RoundDown() != end.RoundDown() { + end = end.RoundDown() + } + n, err := uio.CopyIn(ctx, start, buf[done:done+int(end-start)], opts) + // Look for the terminating zero byte, which may have occurred before + // hitting err. + for i, c := range buf[done : done+n] { + if c == 0 { + return stringFromImmutableBytes(buf[:done+i]), nil + } + } + done += n + if err != nil { + return stringFromImmutableBytes(buf[:done]), err + } + } + return stringFromImmutableBytes(buf), syserror.ENAMETOOLONG +} + +// CopyOutVec copies bytes from src to the memory mapped at ars in uio. The +// maximum number of bytes copied is ars.NumBytes() or len(src), whichever is +// less. CopyOutVec returns the number of bytes copied; if this is less than +// the maximum, it returns a non-nil error explaining why. +// +// Preconditions: As for IO.CopyOut. +func CopyOutVec(ctx context.Context, uio IO, ars AddrRangeSeq, src []byte, opts IOOpts) (int, error) { + var done int + for !ars.IsEmpty() && done < len(src) { + ar := ars.Head() + cplen := len(src) - done + if Addr(cplen) >= ar.Length() { + cplen = int(ar.Length()) + } + n, err := uio.CopyOut(ctx, ar.Start, src[done:done+cplen], opts) + done += n + if err != nil { + return done, err + } + ars = ars.DropFirst(n) + } + return done, nil +} + +// CopyInVec copies bytes from the memory mapped at ars in uio to dst. The +// maximum number of bytes copied is ars.NumBytes() or len(dst), whichever is +// less. CopyInVec returns the number of bytes copied; if this is less than the +// maximum, it returns a non-nil error explaining why. +// +// Preconditions: As for IO.CopyIn. +func CopyInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dst []byte, opts IOOpts) (int, error) { + var done int + for !ars.IsEmpty() && done < len(dst) { + ar := ars.Head() + cplen := len(dst) - done + if Addr(cplen) >= ar.Length() { + cplen = int(ar.Length()) + } + n, err := uio.CopyIn(ctx, ar.Start, dst[done:done+cplen], opts) + done += n + if err != nil { + return done, err + } + ars = ars.DropFirst(n) + } + return done, nil +} + +// ZeroOutVec writes zeroes to the memory mapped at ars in uio. The maximum +// number of bytes written is ars.NumBytes() or toZero, whichever is less. +// ZeroOutVec returns the number of bytes written; if this is less than the +// maximum, it returns a non-nil error explaining why. +// +// Preconditions: As for IO.ZeroOut. +func ZeroOutVec(ctx context.Context, uio IO, ars AddrRangeSeq, toZero int64, opts IOOpts) (int64, error) { + var done int64 + for !ars.IsEmpty() && done < toZero { + ar := ars.Head() + cplen := toZero - done + if Addr(cplen) >= ar.Length() { + cplen = int64(ar.Length()) + } + n, err := uio.ZeroOut(ctx, ar.Start, cplen, opts) + done += n + if err != nil { + return done, err + } + ars = ars.DropFirst64(n) + } + return done, nil +} + +func isASCIIWhitespace(b byte) bool { + // Compare Linux include/linux/ctype.h, lib/ctype.c. + // 9 => horizontal tab '\t' + // 10 => line feed '\n' + // 11 => vertical tab '\v' + // 12 => form feed '\c' + // 13 => carriage return '\r' + return b == ' ' || (b >= 9 && b <= 13) +} + +// CopyInt32StringsInVec copies up to len(dsts) whitespace-separated decimal +// strings from the memory mapped at ars in uio and converts them to int32 +// values in dsts. It returns the number of bytes read. +// +// CopyInt32StringsInVec shares the following properties with Linux's +// kernel/sysctl.c:proc_dointvec(write=1): +// +// - If any read value overflows the range of int32, or any invalid characters +// are encountered during the read, CopyInt32StringsInVec returns EINVAL. +// +// - If, upon reaching the end of ars, fewer than len(dsts) values have been +// read, CopyInt32StringsInVec returns no error if at least 1 value was read +// and EINVAL otherwise. +// +// - Trailing whitespace after the last successfully read value is counted in +// the number of bytes read. +// +// Unlike proc_dointvec(): +// +// - CopyInt32StringsInVec does not implicitly limit ars.NumBytes() to +// PageSize-1; callers that require this must do so explicitly. +// +// - CopyInt32StringsInVec returns EINVAL if ars.NumBytes() == 0. +// +// Preconditions: As for CopyInVec. +func CopyInt32StringsInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dsts []int32, opts IOOpts) (int64, error) { + if len(dsts) == 0 { + return 0, nil + } + + buf := make([]byte, ars.NumBytes()) + n, cperr := CopyInVec(ctx, uio, ars, buf, opts) + buf = buf[:n] + + var i, j int + for ; j < len(dsts); j++ { + // Skip leading whitespace. + for i < len(buf) && isASCIIWhitespace(buf[i]) { + i++ + } + if i == len(buf) { + break + } + + // Find the end of the value to be parsed (next whitespace or end of string). + nextI := i + 1 + for nextI < len(buf) && !isASCIIWhitespace(buf[nextI]) { + nextI++ + } + + // Parse a single value. + val, err := strconv.ParseInt(string(buf[i:nextI]), 10, 32) + if err != nil { + return int64(i), syserror.EINVAL + } + dsts[j] = int32(val) + + i = nextI + } + + // Skip trailing whitespace. + for i < len(buf) && isASCIIWhitespace(buf[i]) { + i++ + } + + if cperr != nil { + return int64(i), cperr + } + if j == 0 { + return int64(i), syserror.EINVAL + } + return int64(i), nil +} + +// CopyInt32StringInVec is equivalent to CopyInt32StringsInVec, but copies at +// most one int32. +func CopyInt32StringInVec(ctx context.Context, uio IO, ars AddrRangeSeq, dst *int32, opts IOOpts) (int64, error) { + dsts := [1]int32{*dst} + n, err := CopyInt32StringsInVec(ctx, uio, ars, dsts[:], opts) + *dst = dsts[0] + return n, err +} + +// IOSequence holds arguments to IO methods. +type IOSequence struct { + IO IO + Addrs AddrRangeSeq + Opts IOOpts +} + +// NumBytes returns s.Addrs.NumBytes(). +// +// Note that NumBytes() may return 0 even if !s.Addrs.IsEmpty(), since +// s.Addrs may contain a non-zero number of zero-length AddrRanges. +// Many clients of +// IOSequence currently do something like: +// +// if ioseq.NumBytes() == 0 { +// return 0, nil +// } +// if f.availableBytes == 0 { +// return 0, syserror.ErrWouldBlock +// } +// return ioseq.CopyOutFrom(..., reader) +// +// In such cases, using s.Addrs.IsEmpty() will cause them to have the wrong +// behavior for zero-length I/O. However, using s.NumBytes() == 0 instead means +// that we will return success for zero-length I/O in cases where Linux would +// return EFAULT due to a failed access_ok() check, so in the long term we +// should move checks for ErrWouldBlock etc. into the body of +// reader.ReadToBlocks and use s.Addrs.IsEmpty() instead. +func (s IOSequence) NumBytes() int64 { + return s.Addrs.NumBytes() +} + +// DropFirst returns a copy of s with s.Addrs.DropFirst(n). +// +// Preconditions: As for AddrRangeSeq.DropFirst. +func (s IOSequence) DropFirst(n int) IOSequence { + return IOSequence{s.IO, s.Addrs.DropFirst(n), s.Opts} +} + +// DropFirst64 returns a copy of s with s.Addrs.DropFirst64(n). +// +// Preconditions: As for AddrRangeSeq.DropFirst64. +func (s IOSequence) DropFirst64(n int64) IOSequence { + return IOSequence{s.IO, s.Addrs.DropFirst64(n), s.Opts} +} + +// TakeFirst returns a copy of s with s.Addrs.TakeFirst(n). +// +// Preconditions: As for AddrRangeSeq.TakeFirst. +func (s IOSequence) TakeFirst(n int) IOSequence { + return IOSequence{s.IO, s.Addrs.TakeFirst(n), s.Opts} +} + +// TakeFirst64 returns a copy of s with s.Addrs.TakeFirst64(n). +// +// Preconditions: As for AddrRangeSeq.TakeFirst64. +func (s IOSequence) TakeFirst64(n int64) IOSequence { + return IOSequence{s.IO, s.Addrs.TakeFirst64(n), s.Opts} +} + +// CopyOut invokes CopyOutVec over s.Addrs. +// +// As with CopyOutVec, if s.NumBytes() < len(src), the copy will be truncated +// to s.NumBytes(), and a nil error will be returned. +// +// Preconditions: As for CopyOutVec. +func (s IOSequence) CopyOut(ctx context.Context, src []byte) (int, error) { + return CopyOutVec(ctx, s.IO, s.Addrs, src, s.Opts) +} + +// CopyIn invokes CopyInVec over s.Addrs. +// +// As with CopyInVec, if s.NumBytes() < len(dst), the copy will be truncated to +// s.NumBytes(), and a nil error will be returned. +// +// Preconditions: As for CopyInVec. +func (s IOSequence) CopyIn(ctx context.Context, dst []byte) (int, error) { + return CopyInVec(ctx, s.IO, s.Addrs, dst, s.Opts) +} + +// ZeroOut invokes ZeroOutVec over s.Addrs. +// +// As with ZeroOutVec, if s.NumBytes() < toZero, the write will be truncated +// to s.NumBytes(), and a nil error will be returned. +// +// Preconditions: As for ZeroOutVec. +func (s IOSequence) ZeroOut(ctx context.Context, toZero int64) (int64, error) { + return ZeroOutVec(ctx, s.IO, s.Addrs, toZero, s.Opts) +} + +// CopyOutFrom invokes s.CopyOutFrom over s.Addrs. +// +// Preconditions: As for IO.CopyOutFrom. +func (s IOSequence) CopyOutFrom(ctx context.Context, src safemem.Reader) (int64, error) { + return s.IO.CopyOutFrom(ctx, s.Addrs, src, s.Opts) +} + +// CopyInTo invokes s.CopyInTo over s.Addrs. +// +// Preconditions: As for IO.CopyInTo. +func (s IOSequence) CopyInTo(ctx context.Context, dst safemem.Writer) (int64, error) { + return s.IO.CopyInTo(ctx, s.Addrs, dst, s.Opts) +} + +// Reader returns an io.Reader that reads from s. Reads beyond the end of s +// return io.EOF. The preconditions that apply to s.CopyIn also apply to the +// returned io.Reader.Read. +func (s IOSequence) Reader(ctx context.Context) io.Reader { + return &ioSequenceReadWriter{ctx, s} +} + +// Writer returns an io.Writer that writes to s. Writes beyond the end of s +// return ErrEndOfIOSequence. The preconditions that apply to s.CopyOut also +// apply to the returned io.Writer.Write. +func (s IOSequence) Writer(ctx context.Context) io.Writer { + return &ioSequenceReadWriter{ctx, s} +} + +// ErrEndOfIOSequence is returned by IOSequence.Writer().Write() when +// attempting to write beyond the end of the IOSequence. +var ErrEndOfIOSequence = errors.New("write beyond end of IOSequence") + +type ioSequenceReadWriter struct { + ctx context.Context + s IOSequence +} + +// Read implements io.Reader.Read. +func (rw *ioSequenceReadWriter) Read(dst []byte) (int, error) { + n, err := rw.s.CopyIn(rw.ctx, dst) + rw.s = rw.s.DropFirst(n) + if err == nil && rw.s.NumBytes() == 0 { + err = io.EOF + } + return n, err +} + +// Write implements io.Writer.Write. +func (rw *ioSequenceReadWriter) Write(src []byte) (int, error) { + n, err := rw.s.CopyOut(rw.ctx, src) + rw.s = rw.s.DropFirst(n) + if err == nil && n < len(src) { + err = ErrEndOfIOSequence + } + return n, err +} diff --git a/pkg/sentry/usermem/usermem_arm64.go b/pkg/sentry/usermem/usermem_arm64.go new file mode 100644 index 000000000..fdfc30a66 --- /dev/null +++ b/pkg/sentry/usermem/usermem_arm64.go @@ -0,0 +1,53 @@ +// Copyright 2019 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. + +// +build arm64 + +package usermem + +import ( + "encoding/binary" + "syscall" +) + +const ( + // PageSize is the system page size. + // arm64 support 4K/16K/64K page size, + // which can be get by syscall.Getpagesize(). + // Currently, only 4K page size is supported. + PageSize = 1 << PageShift + + // HugePageSize is the system huge page size. + HugePageSize = 1 << HugePageShift + + // PageShift is the binary log of the system page size. + PageShift = 12 + + // HugePageShift is the binary log of the system huge page size. + // Should be calculated by "PageShift + (PageShift - 3)" + // when multiple page size support is ready. + HugePageShift = 21 +) + +var ( + // ByteOrder is the native byte order (little endian). + ByteOrder = binary.LittleEndian +) + +func init() { + // Make sure the page size is 4K on arm64 platform. + if size := syscall.Getpagesize(); size != PageSize { + panic("Only 4K page size is supported on arm64!") + } +} diff --git a/pkg/sentry/usermem/usermem_state_autogen.go b/pkg/sentry/usermem/usermem_state_autogen.go new file mode 100755 index 000000000..bc728eab3 --- /dev/null +++ b/pkg/sentry/usermem/usermem_state_autogen.go @@ -0,0 +1,49 @@ +// automatically generated by stateify. + +package usermem + +import ( + "gvisor.googlesource.com/gvisor/pkg/state" +) + +func (x *AccessType) beforeSave() {} +func (x *AccessType) save(m state.Map) { + x.beforeSave() + m.Save("Read", &x.Read) + m.Save("Write", &x.Write) + m.Save("Execute", &x.Execute) +} + +func (x *AccessType) afterLoad() {} +func (x *AccessType) load(m state.Map) { + m.Load("Read", &x.Read) + m.Load("Write", &x.Write) + m.Load("Execute", &x.Execute) +} + +func (x *Addr) save(m state.Map) { + m.SaveValue("", (uintptr)(*x)) +} + +func (x *Addr) load(m state.Map) { + m.LoadValue("", new(uintptr), func(y interface{}) { *x = (Addr)(y.(uintptr)) }) +} + +func (x *AddrRange) beforeSave() {} +func (x *AddrRange) save(m state.Map) { + x.beforeSave() + m.Save("Start", &x.Start) + m.Save("End", &x.End) +} + +func (x *AddrRange) afterLoad() {} +func (x *AddrRange) load(m state.Map) { + m.Load("Start", &x.Start) + m.Load("End", &x.End) +} + +func init() { + state.Register("usermem.AccessType", (*AccessType)(nil), state.Fns{Save: (*AccessType).save, Load: (*AccessType).load}) + state.Register("usermem.Addr", (*Addr)(nil), state.Fns{Save: (*Addr).save, Load: (*Addr).load}) + state.Register("usermem.AddrRange", (*AddrRange)(nil), state.Fns{Save: (*AddrRange).save, Load: (*AddrRange).load}) +} diff --git a/pkg/sentry/usermem/usermem_unsafe.go b/pkg/sentry/usermem/usermem_unsafe.go new file mode 100644 index 000000000..876783e78 --- /dev/null +++ b/pkg/sentry/usermem/usermem_unsafe.go @@ -0,0 +1,27 @@ +// Copyright 2019 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 usermem + +import ( + "unsafe" +) + +// stringFromImmutableBytes is equivalent to string(bs), except that it never +// copies even if escape analysis can't prove that bs does not escape. This is +// only valid if bs is never mutated after stringFromImmutableBytes returns. +func stringFromImmutableBytes(bs []byte) string { + // Compare strings.Builder.String(). + return *(*string)(unsafe.Pointer(&bs)) +} diff --git a/pkg/sentry/usermem/usermem_x86.go b/pkg/sentry/usermem/usermem_x86.go new file mode 100644 index 000000000..8059b72d2 --- /dev/null +++ b/pkg/sentry/usermem/usermem_x86.go @@ -0,0 +1,38 @@ +// 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. + +// +build amd64 i386 + +package usermem + +import "encoding/binary" + +const ( + // PageSize is the system page size. + PageSize = 1 << PageShift + + // HugePageSize is the system huge page size. + HugePageSize = 1 << HugePageShift + + // PageShift is the binary log of the system page size. + PageShift = 12 + + // HugePageShift is the binary log of the system huge page size. + HugePageShift = 21 +) + +var ( + // ByteOrder is the native byte order (little endian). + ByteOrder = binary.LittleEndian +) |