diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/internal')
7 files changed, 675 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/internal/chacha20/asm_s390x.s b/vendor/golang.org/x/crypto/internal/chacha20/asm_s390x.s new file mode 100644 index 0000000..98427c5 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/asm_s390x.s @@ -0,0 +1,283 @@ +// Copyright 2018 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. + +// +build s390x,!gccgo,!appengine + +#include "go_asm.h" +#include "textflag.h" + +// This is an implementation of the ChaCha20 encryption algorithm as +// specified in RFC 7539. It uses vector instructions to compute +// 4 keystream blocks in parallel (256 bytes) which are then XORed +// with the bytes in the input slice. + +GLOBL ·constants<>(SB), RODATA|NOPTR, $32 +// BSWAP: swap bytes in each 4-byte element +DATA ·constants<>+0x00(SB)/4, $0x03020100 +DATA ·constants<>+0x04(SB)/4, $0x07060504 +DATA ·constants<>+0x08(SB)/4, $0x0b0a0908 +DATA ·constants<>+0x0c(SB)/4, $0x0f0e0d0c +// J0: [j0, j1, j2, j3] +DATA ·constants<>+0x10(SB)/4, $0x61707865 +DATA ·constants<>+0x14(SB)/4, $0x3320646e +DATA ·constants<>+0x18(SB)/4, $0x79622d32 +DATA ·constants<>+0x1c(SB)/4, $0x6b206574 + +// EXRL targets: +TEXT ·mvcSrcToBuf(SB), NOFRAME|NOSPLIT, $0 + MVC $1, (R1), (R8) + RET + +TEXT ·mvcBufToDst(SB), NOFRAME|NOSPLIT, $0 + MVC $1, (R8), (R9) + RET + +#define BSWAP V5 +#define J0 V6 +#define KEY0 V7 +#define KEY1 V8 +#define NONCE V9 +#define CTR V10 +#define M0 V11 +#define M1 V12 +#define M2 V13 +#define M3 V14 +#define INC V15 +#define X0 V16 +#define X1 V17 +#define X2 V18 +#define X3 V19 +#define X4 V20 +#define X5 V21 +#define X6 V22 +#define X7 V23 +#define X8 V24 +#define X9 V25 +#define X10 V26 +#define X11 V27 +#define X12 V28 +#define X13 V29 +#define X14 V30 +#define X15 V31 + +#define NUM_ROUNDS 20 + +#define ROUND4(a0, a1, a2, a3, b0, b1, b2, b3, c0, c1, c2, c3, d0, d1, d2, d3) \ + VAF a1, a0, a0 \ + VAF b1, b0, b0 \ + VAF c1, c0, c0 \ + VAF d1, d0, d0 \ + VX a0, a2, a2 \ + VX b0, b2, b2 \ + VX c0, c2, c2 \ + VX d0, d2, d2 \ + VERLLF $16, a2, a2 \ + VERLLF $16, b2, b2 \ + VERLLF $16, c2, c2 \ + VERLLF $16, d2, d2 \ + VAF a2, a3, a3 \ + VAF b2, b3, b3 \ + VAF c2, c3, c3 \ + VAF d2, d3, d3 \ + VX a3, a1, a1 \ + VX b3, b1, b1 \ + VX c3, c1, c1 \ + VX d3, d1, d1 \ + VERLLF $12, a1, a1 \ + VERLLF $12, b1, b1 \ + VERLLF $12, c1, c1 \ + VERLLF $12, d1, d1 \ + VAF a1, a0, a0 \ + VAF b1, b0, b0 \ + VAF c1, c0, c0 \ + VAF d1, d0, d0 \ + VX a0, a2, a2 \ + VX b0, b2, b2 \ + VX c0, c2, c2 \ + VX d0, d2, d2 \ + VERLLF $8, a2, a2 \ + VERLLF $8, b2, b2 \ + VERLLF $8, c2, c2 \ + VERLLF $8, d2, d2 \ + VAF a2, a3, a3 \ + VAF b2, b3, b3 \ + VAF c2, c3, c3 \ + VAF d2, d3, d3 \ + VX a3, a1, a1 \ + VX b3, b1, b1 \ + VX c3, c1, c1 \ + VX d3, d1, d1 \ + VERLLF $7, a1, a1 \ + VERLLF $7, b1, b1 \ + VERLLF $7, c1, c1 \ + VERLLF $7, d1, d1 + +#define PERMUTE(mask, v0, v1, v2, v3) \ + VPERM v0, v0, mask, v0 \ + VPERM v1, v1, mask, v1 \ + VPERM v2, v2, mask, v2 \ + VPERM v3, v3, mask, v3 + +#define ADDV(x, v0, v1, v2, v3) \ + VAF x, v0, v0 \ + VAF x, v1, v1 \ + VAF x, v2, v2 \ + VAF x, v3, v3 + +#define XORV(off, dst, src, v0, v1, v2, v3) \ + VLM off(src), M0, M3 \ + PERMUTE(BSWAP, v0, v1, v2, v3) \ + VX v0, M0, M0 \ + VX v1, M1, M1 \ + VX v2, M2, M2 \ + VX v3, M3, M3 \ + VSTM M0, M3, off(dst) + +#define SHUFFLE(a, b, c, d, t, u, v, w) \ + VMRHF a, c, t \ // t = {a[0], c[0], a[1], c[1]} + VMRHF b, d, u \ // u = {b[0], d[0], b[1], d[1]} + VMRLF a, c, v \ // v = {a[2], c[2], a[3], c[3]} + VMRLF b, d, w \ // w = {b[2], d[2], b[3], d[3]} + VMRHF t, u, a \ // a = {a[0], b[0], c[0], d[0]} + VMRLF t, u, b \ // b = {a[1], b[1], c[1], d[1]} + VMRHF v, w, c \ // c = {a[2], b[2], c[2], d[2]} + VMRLF v, w, d // d = {a[3], b[3], c[3], d[3]} + +// func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32, buf *[256]byte, len *int) +TEXT ·xorKeyStreamVX(SB), NOSPLIT, $0 + MOVD $·constants<>(SB), R1 + MOVD dst+0(FP), R2 // R2=&dst[0] + LMG src+24(FP), R3, R4 // R3=&src[0] R4=len(src) + MOVD key+48(FP), R5 // R5=key + MOVD nonce+56(FP), R6 // R6=nonce + MOVD counter+64(FP), R7 // R7=counter + MOVD buf+72(FP), R8 // R8=buf + MOVD len+80(FP), R9 // R9=len + + // load BSWAP and J0 + VLM (R1), BSWAP, J0 + + // set up tail buffer + ADD $-1, R4, R12 + MOVBZ R12, R12 + CMPUBEQ R12, $255, aligned + MOVD R4, R1 + AND $~255, R1 + MOVD $(R3)(R1*1), R1 + EXRL $·mvcSrcToBuf(SB), R12 + MOVD $255, R0 + SUB R12, R0 + MOVD R0, (R9) // update len + +aligned: + // setup + MOVD $95, R0 + VLM (R5), KEY0, KEY1 + VLL R0, (R6), NONCE + VZERO M0 + VLEIB $7, $32, M0 + VSRLB M0, NONCE, NONCE + + // initialize counter values + VLREPF (R7), CTR + VZERO INC + VLEIF $1, $1, INC + VLEIF $2, $2, INC + VLEIF $3, $3, INC + VAF INC, CTR, CTR + VREPIF $4, INC + +chacha: + VREPF $0, J0, X0 + VREPF $1, J0, X1 + VREPF $2, J0, X2 + VREPF $3, J0, X3 + VREPF $0, KEY0, X4 + VREPF $1, KEY0, X5 + VREPF $2, KEY0, X6 + VREPF $3, KEY0, X7 + VREPF $0, KEY1, X8 + VREPF $1, KEY1, X9 + VREPF $2, KEY1, X10 + VREPF $3, KEY1, X11 + VLR CTR, X12 + VREPF $1, NONCE, X13 + VREPF $2, NONCE, X14 + VREPF $3, NONCE, X15 + + MOVD $(NUM_ROUNDS/2), R1 + +loop: + ROUND4(X0, X4, X12, X8, X1, X5, X13, X9, X2, X6, X14, X10, X3, X7, X15, X11) + ROUND4(X0, X5, X15, X10, X1, X6, X12, X11, X2, X7, X13, X8, X3, X4, X14, X9) + + ADD $-1, R1 + BNE loop + + // decrement length + ADD $-256, R4 + BLT tail + +continue: + // rearrange vectors + SHUFFLE(X0, X1, X2, X3, M0, M1, M2, M3) + ADDV(J0, X0, X1, X2, X3) + SHUFFLE(X4, X5, X6, X7, M0, M1, M2, M3) + ADDV(KEY0, X4, X5, X6, X7) + SHUFFLE(X8, X9, X10, X11, M0, M1, M2, M3) + ADDV(KEY1, X8, X9, X10, X11) + VAF CTR, X12, X12 + SHUFFLE(X12, X13, X14, X15, M0, M1, M2, M3) + ADDV(NONCE, X12, X13, X14, X15) + + // increment counters + VAF INC, CTR, CTR + + // xor keystream with plaintext + XORV(0*64, R2, R3, X0, X4, X8, X12) + XORV(1*64, R2, R3, X1, X5, X9, X13) + XORV(2*64, R2, R3, X2, X6, X10, X14) + XORV(3*64, R2, R3, X3, X7, X11, X15) + + // increment pointers + MOVD $256(R2), R2 + MOVD $256(R3), R3 + + CMPBNE R4, $0, chacha + CMPUBEQ R12, $255, return + EXRL $·mvcBufToDst(SB), R12 // len was updated during setup + +return: + VSTEF $0, CTR, (R7) + RET + +tail: + MOVD R2, R9 + MOVD R8, R2 + MOVD R8, R3 + MOVD $0, R4 + JMP continue + +// func hasVectorFacility() bool +TEXT ·hasVectorFacility(SB), NOSPLIT, $24-1 + MOVD $x-24(SP), R1 + XC $24, 0(R1), 0(R1) // clear the storage + MOVD $2, R0 // R0 is the number of double words stored -1 + WORD $0xB2B01000 // STFLE 0(R1) + XOR R0, R0 // reset the value of R0 + MOVBZ z-8(SP), R1 + AND $0x40, R1 + BEQ novector + +vectorinstalled: + // check if the vector instruction has been enabled + VLEIB $0, $0xF, V16 + VLGVB $0, V16, R1 + CMPBNE R1, $0xF, novector + MOVB $1, ret+0(FP) // have vx + RET + +novector: + MOVB $0, ret+0(FP) // no vx + RET diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go new file mode 100644 index 0000000..523751f --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go @@ -0,0 +1,236 @@ +// Copyright 2016 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. + +// Package ChaCha20 implements the core ChaCha20 function as specified +// in https://tools.ietf.org/html/rfc7539#section-2.3. +package chacha20 + +import ( + "crypto/cipher" + "encoding/binary" + + "golang.org/x/crypto/internal/subtle" +) + +// assert that *Cipher implements cipher.Stream +var _ cipher.Stream = (*Cipher)(nil) + +// Cipher is a stateful instance of ChaCha20 using a particular key +// and nonce. A *Cipher implements the cipher.Stream interface. +type Cipher struct { + key [8]uint32 + counter uint32 // incremented after each block + nonce [3]uint32 + buf [bufSize]byte // buffer for unused keystream bytes + len int // number of unused keystream bytes at end of buf +} + +// New creates a new ChaCha20 stream cipher with the given key and nonce. +// The initial counter value is set to 0. +func New(key [8]uint32, nonce [3]uint32) *Cipher { + return &Cipher{key: key, nonce: nonce} +} + +// XORKeyStream XORs each byte in the given slice with a byte from the +// cipher's key stream. Dst and src must overlap entirely or not at all. +// +// If len(dst) < len(src), XORKeyStream will panic. It is acceptable +// to pass a dst bigger than src, and in that case, XORKeyStream will +// only update dst[:len(src)] and will not touch the rest of dst. +// +// Multiple calls to XORKeyStream behave as if the concatenation of +// the src buffers was passed in a single run. That is, Cipher +// maintains state and does not reset at each XORKeyStream call. +func (s *Cipher) XORKeyStream(dst, src []byte) { + if len(dst) < len(src) { + panic("chacha20: output smaller than input") + } + if subtle.InexactOverlap(dst[:len(src)], src) { + panic("chacha20: invalid buffer overlap") + } + + // xor src with buffered keystream first + if s.len != 0 { + buf := s.buf[len(s.buf)-s.len:] + if len(src) < len(buf) { + buf = buf[:len(src)] + } + td, ts := dst[:len(buf)], src[:len(buf)] // BCE hint + for i, b := range buf { + td[i] = ts[i] ^ b + } + s.len -= len(buf) + if s.len != 0 { + return + } + s.buf = [len(s.buf)]byte{} // zero the empty buffer + src = src[len(buf):] + dst = dst[len(buf):] + } + + if len(src) == 0 { + return + } + if haveAsm { + s.xorKeyStreamAsm(dst, src) + return + } + + // set up a 64-byte buffer to pad out the final block if needed + // (hoisted out of the main loop to avoid spills) + rem := len(src) % 64 // length of final block + fin := len(src) - rem // index of final block + if rem > 0 { + copy(s.buf[len(s.buf)-64:], src[fin:]) + } + + // qr calculates a quarter round + qr := func(a, b, c, d uint32) (uint32, uint32, uint32, uint32) { + a += b + d ^= a + d = (d << 16) | (d >> 16) + c += d + b ^= c + b = (b << 12) | (b >> 20) + a += b + d ^= a + d = (d << 8) | (d >> 24) + c += d + b ^= c + b = (b << 7) | (b >> 25) + return a, b, c, d + } + + // ChaCha20 constants + const ( + j0 = 0x61707865 + j1 = 0x3320646e + j2 = 0x79622d32 + j3 = 0x6b206574 + ) + + // pre-calculate most of the first round + s1, s5, s9, s13 := qr(j1, s.key[1], s.key[5], s.nonce[0]) + s2, s6, s10, s14 := qr(j2, s.key[2], s.key[6], s.nonce[1]) + s3, s7, s11, s15 := qr(j3, s.key[3], s.key[7], s.nonce[2]) + + n := len(src) + src, dst = src[:n:n], dst[:n:n] // BCE hint + for i := 0; i < n; i += 64 { + // calculate the remainder of the first round + s0, s4, s8, s12 := qr(j0, s.key[0], s.key[4], s.counter) + + // execute the second round + x0, x5, x10, x15 := qr(s0, s5, s10, s15) + x1, x6, x11, x12 := qr(s1, s6, s11, s12) + x2, x7, x8, x13 := qr(s2, s7, s8, s13) + x3, x4, x9, x14 := qr(s3, s4, s9, s14) + + // execute the remaining 18 rounds + for i := 0; i < 9; i++ { + x0, x4, x8, x12 = qr(x0, x4, x8, x12) + x1, x5, x9, x13 = qr(x1, x5, x9, x13) + x2, x6, x10, x14 = qr(x2, x6, x10, x14) + x3, x7, x11, x15 = qr(x3, x7, x11, x15) + + x0, x5, x10, x15 = qr(x0, x5, x10, x15) + x1, x6, x11, x12 = qr(x1, x6, x11, x12) + x2, x7, x8, x13 = qr(x2, x7, x8, x13) + x3, x4, x9, x14 = qr(x3, x4, x9, x14) + } + + x0 += j0 + x1 += j1 + x2 += j2 + x3 += j3 + + x4 += s.key[0] + x5 += s.key[1] + x6 += s.key[2] + x7 += s.key[3] + x8 += s.key[4] + x9 += s.key[5] + x10 += s.key[6] + x11 += s.key[7] + + x12 += s.counter + x13 += s.nonce[0] + x14 += s.nonce[1] + x15 += s.nonce[2] + + // increment the counter + s.counter += 1 + if s.counter == 0 { + panic("chacha20: counter overflow") + } + + // pad to 64 bytes if needed + in, out := src[i:], dst[i:] + if i == fin { + // src[fin:] has already been copied into s.buf before + // the main loop + in, out = s.buf[len(s.buf)-64:], s.buf[len(s.buf)-64:] + } + in, out = in[:64], out[:64] // BCE hint + + // XOR the key stream with the source and write out the result + xor(out[0:], in[0:], x0) + xor(out[4:], in[4:], x1) + xor(out[8:], in[8:], x2) + xor(out[12:], in[12:], x3) + xor(out[16:], in[16:], x4) + xor(out[20:], in[20:], x5) + xor(out[24:], in[24:], x6) + xor(out[28:], in[28:], x7) + xor(out[32:], in[32:], x8) + xor(out[36:], in[36:], x9) + xor(out[40:], in[40:], x10) + xor(out[44:], in[44:], x11) + xor(out[48:], in[48:], x12) + xor(out[52:], in[52:], x13) + xor(out[56:], in[56:], x14) + xor(out[60:], in[60:], x15) + } + // copy any trailing bytes out of the buffer and into dst + if rem != 0 { + s.len = 64 - rem + copy(dst[fin:], s.buf[len(s.buf)-64:]) + } +} + +// Advance discards bytes in the key stream until the next 64 byte block +// boundary is reached and updates the counter accordingly. If the key +// stream is already at a block boundary no bytes will be discarded and +// the counter will be unchanged. +func (s *Cipher) Advance() { + s.len -= s.len % 64 + if s.len == 0 { + s.buf = [len(s.buf)]byte{} + } +} + +// XORKeyStream crypts bytes from in to out using the given key and counters. +// In and out must overlap entirely or not at all. Counter contains the raw +// ChaCha20 counter bytes (i.e. block counter followed by nonce). +func XORKeyStream(out, in []byte, counter *[16]byte, key *[32]byte) { + s := Cipher{ + key: [8]uint32{ + binary.LittleEndian.Uint32(key[0:4]), + binary.LittleEndian.Uint32(key[4:8]), + binary.LittleEndian.Uint32(key[8:12]), + binary.LittleEndian.Uint32(key[12:16]), + binary.LittleEndian.Uint32(key[16:20]), + binary.LittleEndian.Uint32(key[20:24]), + binary.LittleEndian.Uint32(key[24:28]), + binary.LittleEndian.Uint32(key[28:32]), + }, + nonce: [3]uint32{ + binary.LittleEndian.Uint32(counter[4:8]), + binary.LittleEndian.Uint32(counter[8:12]), + binary.LittleEndian.Uint32(counter[12:16]), + }, + counter: binary.LittleEndian.Uint32(counter[0:4]), + } + s.XORKeyStream(out, in) +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go new file mode 100644 index 0000000..91520d1 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_noasm.go @@ -0,0 +1,16 @@ +// Copyright 2018 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. + +// +build !s390x gccgo appengine + +package chacha20 + +const ( + bufSize = 64 + haveAsm = false +) + +func (*Cipher) xorKeyStreamAsm(dst, src []byte) { + panic("not implemented") +} diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go new file mode 100644 index 0000000..0c1c671 --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_s390x.go @@ -0,0 +1,30 @@ +// Copyright 2018 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. + +// +build s390x,!gccgo,!appengine + +package chacha20 + +var haveAsm = hasVectorFacility() + +const bufSize = 256 + +// hasVectorFacility reports whether the machine supports the vector +// facility (vx). +// Implementation in asm_s390x.s. +func hasVectorFacility() bool + +// xorKeyStreamVX is an assembly implementation of XORKeyStream. It must only +// be called when the vector facility is available. +// Implementation in asm_s390x.s. +//go:noescape +func xorKeyStreamVX(dst, src []byte, key *[8]uint32, nonce *[3]uint32, counter *uint32, buf *[256]byte, len *int) + +func (c *Cipher) xorKeyStreamAsm(dst, src []byte) { + xorKeyStreamVX(dst, src, &c.key, &c.nonce, &c.counter, &c.buf, &c.len) +} + +// EXRL targets, DO NOT CALL! +func mvcSrcToBuf() +func mvcBufToDst() diff --git a/vendor/golang.org/x/crypto/internal/chacha20/xor.go b/vendor/golang.org/x/crypto/internal/chacha20/xor.go new file mode 100644 index 0000000..9c5ba0b --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/chacha20/xor.go @@ -0,0 +1,43 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found src the LICENSE file. + +package chacha20 + +import ( + "runtime" +) + +// Platforms that have fast unaligned 32-bit little endian accesses. +const unaligned = runtime.GOARCH == "386" || + runtime.GOARCH == "amd64" || + runtime.GOARCH == "arm64" || + runtime.GOARCH == "ppc64le" || + runtime.GOARCH == "s390x" + +// xor reads a little endian uint32 from src, XORs it with u and +// places the result in little endian byte order in dst. +func xor(dst, src []byte, u uint32) { + _, _ = src[3], dst[3] // eliminate bounds checks + if unaligned { + // The compiler should optimize this code into + // 32-bit unaligned little endian loads and stores. + // TODO: delete once the compiler does a reliably + // good job with the generic code below. + // See issue #25111 for more details. + v := uint32(src[0]) + v |= uint32(src[1]) << 8 + v |= uint32(src[2]) << 16 + v |= uint32(src[3]) << 24 + v ^= u + dst[0] = byte(v) + dst[1] = byte(v >> 8) + dst[2] = byte(v >> 16) + dst[3] = byte(v >> 24) + } else { + dst[0] = src[0] ^ byte(u) + dst[1] = src[1] ^ byte(u>>8) + dst[2] = src[2] ^ byte(u>>16) + dst[3] = src[3] ^ byte(u>>24) + } +} diff --git a/vendor/golang.org/x/crypto/internal/subtle/aliasing.go b/vendor/golang.org/x/crypto/internal/subtle/aliasing.go new file mode 100644 index 0000000..f38797b --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/subtle/aliasing.go @@ -0,0 +1,32 @@ +// Copyright 2018 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. + +// +build !appengine + +// Package subtle implements functions that are often useful in cryptographic +// code but require careful thought to use correctly. +package subtle // import "golang.org/x/crypto/internal/subtle" + +import "unsafe" + +// AnyOverlap reports whether x and y share memory at any (not necessarily +// corresponding) index. The memory beyond the slice length is ignored. +func AnyOverlap(x, y []byte) bool { + return len(x) > 0 && len(y) > 0 && + uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) && + uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1])) +} + +// InexactOverlap reports whether x and y share memory at any non-corresponding +// index. The memory beyond the slice length is ignored. Note that x and y can +// have different lengths and still not have any inexact overlap. +// +// InexactOverlap can be used to implement the requirements of the crypto/cipher +// AEAD, Block, BlockMode and Stream interfaces. +func InexactOverlap(x, y []byte) bool { + if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] { + return false + } + return AnyOverlap(x, y) +} diff --git a/vendor/golang.org/x/crypto/internal/subtle/aliasing_appengine.go b/vendor/golang.org/x/crypto/internal/subtle/aliasing_appengine.go new file mode 100644 index 0000000..0cc4a8a --- /dev/null +++ b/vendor/golang.org/x/crypto/internal/subtle/aliasing_appengine.go @@ -0,0 +1,35 @@ +// Copyright 2018 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. + +// +build appengine + +// Package subtle implements functions that are often useful in cryptographic +// code but require careful thought to use correctly. +package subtle // import "golang.org/x/crypto/internal/subtle" + +// This is the Google App Engine standard variant based on reflect +// because the unsafe package and cgo are disallowed. + +import "reflect" + +// AnyOverlap reports whether x and y share memory at any (not necessarily +// corresponding) index. The memory beyond the slice length is ignored. +func AnyOverlap(x, y []byte) bool { + return len(x) > 0 && len(y) > 0 && + reflect.ValueOf(&x[0]).Pointer() <= reflect.ValueOf(&y[len(y)-1]).Pointer() && + reflect.ValueOf(&y[0]).Pointer() <= reflect.ValueOf(&x[len(x)-1]).Pointer() +} + +// InexactOverlap reports whether x and y share memory at any non-corresponding +// index. The memory beyond the slice length is ignored. Note that x and y can +// have different lengths and still not have any inexact overlap. +// +// InexactOverlap can be used to implement the requirements of the crypto/cipher +// AEAD, Block, BlockMode and Stream interfaces. +func InexactOverlap(x, y []byte) bool { + if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] { + return false + } + return AnyOverlap(x, y) +} |