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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:23:18 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:23:18 +0000
commit43a123c1ae6613b3efeed291fa552ecd909d3acf (patch)
treefd92518b7024bc74031f78a1cf9e454b65e73665 /src/crypto/rand
parentInitial commit. (diff)
downloadgolang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz
golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/crypto/rand')
-rw-r--r--src/crypto/rand/example_test.go28
-rw-r--r--src/crypto/rand/rand.go44
-rw-r--r--src/crypto/rand/rand_batched_test.go75
-rw-r--r--src/crypto/rand/rand_getentropy.go14
-rw-r--r--src/crypto/rand/rand_getrandom.go48
-rw-r--r--src/crypto/rand/rand_js.go28
-rw-r--r--src/crypto/rand/rand_plan9.go87
-rw-r--r--src/crypto/rand/rand_test.go43
-rw-r--r--src/crypto/rand/rand_unix.go87
-rw-r--r--src/crypto/rand/rand_windows.go26
-rw-r--r--src/crypto/rand/util.go99
-rw-r--r--src/crypto/rand/util_test.go149
12 files changed, 728 insertions, 0 deletions
diff --git a/src/crypto/rand/example_test.go b/src/crypto/rand/example_test.go
new file mode 100644
index 0000000..ed18647
--- /dev/null
+++ b/src/crypto/rand/example_test.go
@@ -0,0 +1,28 @@
+// Copyright 2011 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 rand_test
+
+import (
+ "bytes"
+ "crypto/rand"
+ "fmt"
+)
+
+// This example reads 10 cryptographically secure pseudorandom numbers from
+// rand.Reader and writes them to a byte slice.
+func ExampleRead() {
+ c := 10
+ b := make([]byte, c)
+ _, err := rand.Read(b)
+ if err != nil {
+ fmt.Println("error:", err)
+ return
+ }
+ // The slice should now contain random bytes instead of only zeroes.
+ fmt.Println(bytes.Equal(b, make([]byte, c)))
+
+ // Output:
+ // false
+}
diff --git a/src/crypto/rand/rand.go b/src/crypto/rand/rand.go
new file mode 100644
index 0000000..af85b96
--- /dev/null
+++ b/src/crypto/rand/rand.go
@@ -0,0 +1,44 @@
+// Copyright 2010 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 rand implements a cryptographically secure
+// random number generator.
+package rand
+
+import "io"
+
+// Reader is a global, shared instance of a cryptographically
+// secure random number generator.
+//
+// On Linux, FreeBSD, Dragonfly and Solaris, Reader uses getrandom(2) if
+// available, /dev/urandom otherwise.
+// On OpenBSD and macOS, Reader uses getentropy(2).
+// On other Unix-like systems, Reader reads from /dev/urandom.
+// On Windows systems, Reader uses the RtlGenRandom API.
+// On Wasm, Reader uses the Web Crypto API.
+var Reader io.Reader
+
+// Read is a helper function that calls Reader.Read using io.ReadFull.
+// On return, n == len(b) if and only if err == nil.
+func Read(b []byte) (n int, err error) {
+ return io.ReadFull(Reader, b)
+}
+
+// batched returns a function that calls f to populate a []byte by chunking it
+// into subslices of, at most, readMax bytes.
+func batched(f func([]byte) error, readMax int) func([]byte) error {
+ return func(out []byte) error {
+ for len(out) > 0 {
+ read := len(out)
+ if read > readMax {
+ read = readMax
+ }
+ if err := f(out[:read]); err != nil {
+ return err
+ }
+ out = out[read:]
+ }
+ return nil
+ }
+}
diff --git a/src/crypto/rand/rand_batched_test.go b/src/crypto/rand/rand_batched_test.go
new file mode 100644
index 0000000..02f4893
--- /dev/null
+++ b/src/crypto/rand/rand_batched_test.go
@@ -0,0 +1,75 @@
+// 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.
+
+//go:build unix
+
+package rand
+
+import (
+ "bytes"
+ "errors"
+ prand "math/rand"
+ "testing"
+)
+
+func TestBatched(t *testing.T) {
+ fillBatched := batched(func(p []byte) error {
+ for i := range p {
+ p[i] = byte(i)
+ }
+ return nil
+ }, 5)
+
+ p := make([]byte, 13)
+ if err := fillBatched(p); err != nil {
+ t.Fatalf("batched function returned error: %s", err)
+ }
+ expected := []byte{0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2}
+ if !bytes.Equal(expected, p) {
+ t.Errorf("incorrect batch result: got %x, want %x", p, expected)
+ }
+}
+
+func TestBatchedBuffering(t *testing.T) {
+ backingStore := make([]byte, 1<<23)
+ prand.Read(backingStore)
+ backingMarker := backingStore[:]
+ output := make([]byte, len(backingStore))
+ outputMarker := output[:]
+
+ fillBatched := batched(func(p []byte) error {
+ n := copy(p, backingMarker)
+ backingMarker = backingMarker[n:]
+ return nil
+ }, 731)
+
+ for len(outputMarker) > 0 {
+ max := 9200
+ if max > len(outputMarker) {
+ max = len(outputMarker)
+ }
+ howMuch := prand.Intn(max + 1)
+ if err := fillBatched(outputMarker[:howMuch]); err != nil {
+ t.Fatalf("batched function returned error: %s", err)
+ }
+ outputMarker = outputMarker[howMuch:]
+ }
+ if !bytes.Equal(backingStore, output) {
+ t.Error("incorrect batch result")
+ }
+}
+
+func TestBatchedError(t *testing.T) {
+ b := batched(func(p []byte) error { return errors.New("failure") }, 5)
+ if b(make([]byte, 13)) == nil {
+ t.Fatal("batched function should have returned an error")
+ }
+}
+
+func TestBatchedEmpty(t *testing.T) {
+ b := batched(func(p []byte) error { return errors.New("failure") }, 5)
+ if b(make([]byte, 0)) != nil {
+ t.Fatal("empty slice should always return successful")
+ }
+}
diff --git a/src/crypto/rand/rand_getentropy.go b/src/crypto/rand/rand_getentropy.go
new file mode 100644
index 0000000..68f921b
--- /dev/null
+++ b/src/crypto/rand/rand_getentropy.go
@@ -0,0 +1,14 @@
+// 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.
+
+//go:build (darwin && !ios) || openbsd
+
+package rand
+
+import "internal/syscall/unix"
+
+func init() {
+ // getentropy(2) returns a maximum of 256 bytes per call
+ altGetRandom = batched(unix.GetEntropy, 256)
+}
diff --git a/src/crypto/rand/rand_getrandom.go b/src/crypto/rand/rand_getrandom.go
new file mode 100644
index 0000000..478aa5c
--- /dev/null
+++ b/src/crypto/rand/rand_getrandom.go
@@ -0,0 +1,48 @@
+// 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.
+
+//go:build linux || freebsd || dragonfly || solaris
+
+package rand
+
+import (
+ "internal/syscall/unix"
+ "runtime"
+ "syscall"
+)
+
+func init() {
+ var maxGetRandomRead int
+ switch runtime.GOOS {
+ case "linux", "android":
+ // Per the manpage:
+ // When reading from the urandom source, a maximum of 33554431 bytes
+ // is returned by a single call to getrandom() on systems where int
+ // has a size of 32 bits.
+ maxGetRandomRead = (1 << 25) - 1
+ case "freebsd", "dragonfly", "solaris", "illumos":
+ maxGetRandomRead = 1 << 8
+ default:
+ panic("no maximum specified for GetRandom")
+ }
+ altGetRandom = batched(getRandom, maxGetRandomRead)
+}
+
+// If the kernel is too old to support the getrandom syscall(),
+// unix.GetRandom will immediately return ENOSYS and we will then fall back to
+// reading from /dev/urandom in rand_unix.go. unix.GetRandom caches the ENOSYS
+// result so we only suffer the syscall overhead once in this case.
+// If the kernel supports the getrandom() syscall, unix.GetRandom will block
+// until the kernel has sufficient randomness (as we don't use GRND_NONBLOCK).
+// In this case, unix.GetRandom will not return an error.
+func getRandom(p []byte) error {
+ n, err := unix.GetRandom(p, 0)
+ if err != nil {
+ return err
+ }
+ if n != len(p) {
+ return syscall.EIO
+ }
+ return nil
+}
diff --git a/src/crypto/rand/rand_js.go b/src/crypto/rand/rand_js.go
new file mode 100644
index 0000000..91e69fa
--- /dev/null
+++ b/src/crypto/rand/rand_js.go
@@ -0,0 +1,28 @@
+// 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.
+
+//go:build js && wasm
+
+package rand
+
+import "syscall/js"
+
+func init() {
+ Reader = &reader{}
+}
+
+var jsCrypto = js.Global().Get("crypto")
+var uint8Array = js.Global().Get("Uint8Array")
+
+// reader implements a pseudorandom generator
+// using JavaScript crypto.getRandomValues method.
+// See https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues.
+type reader struct{}
+
+func (r *reader) Read(b []byte) (int, error) {
+ a := uint8Array.New(len(b))
+ jsCrypto.Call("getRandomValues", a)
+ js.CopyBytesToGo(b, a)
+ return len(b), nil
+}
diff --git a/src/crypto/rand/rand_plan9.go b/src/crypto/rand/rand_plan9.go
new file mode 100644
index 0000000..5d0af09
--- /dev/null
+++ b/src/crypto/rand/rand_plan9.go
@@ -0,0 +1,87 @@
+// Copyright 2010 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.
+
+// Plan9 cryptographically secure pseudorandom number
+// generator.
+
+package rand
+
+import (
+ "crypto/aes"
+ "encoding/binary"
+ "io"
+ "os"
+ "sync"
+ "time"
+)
+
+const randomDevice = "/dev/random"
+
+func init() {
+ Reader = &reader{}
+}
+
+// reader is a new pseudorandom generator that seeds itself by
+// reading from /dev/random. The Read method on the returned
+// reader always returns the full amount asked for, or else it
+// returns an error. The generator is a fast key erasure RNG.
+type reader struct {
+ mu sync.Mutex
+ seeded sync.Once
+ seedErr error
+ key [32]byte
+}
+
+func (r *reader) Read(b []byte) (n int, err error) {
+ r.seeded.Do(func() {
+ t := time.AfterFunc(time.Minute, func() {
+ println("crypto/rand: blocked for 60 seconds waiting to read random data from the kernel")
+ })
+ defer t.Stop()
+ entropy, err := os.Open(randomDevice)
+ if err != nil {
+ r.seedErr = err
+ return
+ }
+ _, r.seedErr = io.ReadFull(entropy, r.key[:])
+ })
+ if r.seedErr != nil {
+ return 0, r.seedErr
+ }
+
+ r.mu.Lock()
+ blockCipher, err := aes.NewCipher(r.key[:])
+ if err != nil {
+ r.mu.Unlock()
+ return 0, err
+ }
+ var (
+ counter uint64
+ block [aes.BlockSize]byte
+ )
+ inc := func() {
+ counter++
+ if counter == 0 {
+ panic("crypto/rand counter wrapped")
+ }
+ binary.LittleEndian.PutUint64(block[:], counter)
+ }
+ blockCipher.Encrypt(r.key[:aes.BlockSize], block[:])
+ inc()
+ blockCipher.Encrypt(r.key[aes.BlockSize:], block[:])
+ inc()
+ r.mu.Unlock()
+
+ n = len(b)
+ for len(b) >= aes.BlockSize {
+ blockCipher.Encrypt(b[:aes.BlockSize], block[:])
+ inc()
+ b = b[aes.BlockSize:]
+ }
+ if len(b) > 0 {
+ blockCipher.Encrypt(block[:], block[:])
+ copy(b, block[:])
+ }
+ return n, nil
+}
diff --git a/src/crypto/rand/rand_test.go b/src/crypto/rand/rand_test.go
new file mode 100644
index 0000000..e45f58e
--- /dev/null
+++ b/src/crypto/rand/rand_test.go
@@ -0,0 +1,43 @@
+// Copyright 2010 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 rand
+
+import (
+ "bytes"
+ "compress/flate"
+ "io"
+ "testing"
+)
+
+func TestRead(t *testing.T) {
+ var n int = 4e6
+ if testing.Short() {
+ n = 1e5
+ }
+ b := make([]byte, n)
+ n, err := io.ReadFull(Reader, b)
+ if n != len(b) || err != nil {
+ t.Fatalf("ReadFull(buf) = %d, %s", n, err)
+ }
+
+ var z bytes.Buffer
+ f, _ := flate.NewWriter(&z, 5)
+ f.Write(b)
+ f.Close()
+ if z.Len() < len(b)*99/100 {
+ t.Fatalf("Compressed %d -> %d", len(b), z.Len())
+ }
+}
+
+func TestReadEmpty(t *testing.T) {
+ n, err := Reader.Read(make([]byte, 0))
+ if n != 0 || err != nil {
+ t.Fatalf("Read(make([]byte, 0)) = %d, %v", n, err)
+ }
+ n, err = Reader.Read(nil)
+ if n != 0 || err != nil {
+ t.Fatalf("Read(nil) = %d, %v", n, err)
+ }
+}
diff --git a/src/crypto/rand/rand_unix.go b/src/crypto/rand/rand_unix.go
new file mode 100644
index 0000000..40fce36
--- /dev/null
+++ b/src/crypto/rand/rand_unix.go
@@ -0,0 +1,87 @@
+// Copyright 2010 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.
+
+//go:build unix
+
+// Unix cryptographically secure pseudorandom number
+// generator.
+
+package rand
+
+import (
+ "crypto/internal/boring"
+ "errors"
+ "io"
+ "os"
+ "sync"
+ "sync/atomic"
+ "syscall"
+ "time"
+)
+
+const urandomDevice = "/dev/urandom"
+
+func init() {
+ if boring.Enabled {
+ Reader = boring.RandReader
+ return
+ }
+ Reader = &reader{}
+}
+
+// A reader satisfies reads by reading from urandomDevice
+type reader struct {
+ f io.Reader
+ mu sync.Mutex
+ used atomic.Uint32 // Atomic: 0 - never used, 1 - used, but f == nil, 2 - used, and f != nil
+}
+
+// altGetRandom if non-nil specifies an OS-specific function to get
+// urandom-style randomness.
+var altGetRandom func([]byte) (err error)
+
+func warnBlocked() {
+ println("crypto/rand: blocked for 60 seconds waiting to read random data from the kernel")
+}
+
+func (r *reader) Read(b []byte) (n int, err error) {
+ boring.Unreachable()
+ if r.used.CompareAndSwap(0, 1) {
+ // First use of randomness. Start timer to warn about
+ // being blocked on entropy not being available.
+ t := time.AfterFunc(time.Minute, warnBlocked)
+ defer t.Stop()
+ }
+ if altGetRandom != nil && altGetRandom(b) == nil {
+ return len(b), nil
+ }
+ if r.used.Load() != 2 {
+ r.mu.Lock()
+ if r.used.Load() != 2 {
+ f, err := os.Open(urandomDevice)
+ if err != nil {
+ r.mu.Unlock()
+ return 0, err
+ }
+ r.f = hideAgainReader{f}
+ r.used.Store(2)
+ }
+ r.mu.Unlock()
+ }
+ return io.ReadFull(r.f, b)
+}
+
+// hideAgainReader masks EAGAIN reads from /dev/urandom.
+// See golang.org/issue/9205
+type hideAgainReader struct {
+ r io.Reader
+}
+
+func (hr hideAgainReader) Read(p []byte) (n int, err error) {
+ n, err = hr.r.Read(p)
+ if errors.Is(err, syscall.EAGAIN) {
+ err = nil
+ }
+ return
+}
diff --git a/src/crypto/rand/rand_windows.go b/src/crypto/rand/rand_windows.go
new file mode 100644
index 0000000..6c0655c
--- /dev/null
+++ b/src/crypto/rand/rand_windows.go
@@ -0,0 +1,26 @@
+// Copyright 2010 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.
+
+// Windows cryptographically secure pseudorandom number
+// generator.
+
+package rand
+
+import (
+ "internal/syscall/windows"
+)
+
+func init() { Reader = &rngReader{} }
+
+type rngReader struct{}
+
+func (r *rngReader) Read(b []byte) (n int, err error) {
+ // RtlGenRandom only returns 1<<32-1 bytes at a time. We only read at
+ // most 1<<31-1 bytes at a time so that this works the same on 32-bit
+ // and 64-bit systems.
+ if err := batched(windows.RtlGenRandom, 1<<31-1)(b); err != nil {
+ return 0, err
+ }
+ return len(b), nil
+}
diff --git a/src/crypto/rand/util.go b/src/crypto/rand/util.go
new file mode 100644
index 0000000..11b1a28
--- /dev/null
+++ b/src/crypto/rand/util.go
@@ -0,0 +1,99 @@
+// Copyright 2011 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 rand
+
+import (
+ "crypto/internal/randutil"
+ "errors"
+ "io"
+ "math/big"
+)
+
+// Prime returns a number of the given bit length that is prime with high probability.
+// Prime will return error for any error returned by rand.Read or if bits < 2.
+func Prime(rand io.Reader, bits int) (*big.Int, error) {
+ if bits < 2 {
+ return nil, errors.New("crypto/rand: prime size must be at least 2-bit")
+ }
+
+ randutil.MaybeReadByte(rand)
+
+ b := uint(bits % 8)
+ if b == 0 {
+ b = 8
+ }
+
+ bytes := make([]byte, (bits+7)/8)
+ p := new(big.Int)
+
+ for {
+ if _, err := io.ReadFull(rand, bytes); err != nil {
+ return nil, err
+ }
+
+ // Clear bits in the first byte to make sure the candidate has a size <= bits.
+ bytes[0] &= uint8(int(1<<b) - 1)
+ // Don't let the value be too small, i.e, set the most significant two bits.
+ // Setting the top two bits, rather than just the top bit,
+ // means that when two of these values are multiplied together,
+ // the result isn't ever one bit short.
+ if b >= 2 {
+ bytes[0] |= 3 << (b - 2)
+ } else {
+ // Here b==1, because b cannot be zero.
+ bytes[0] |= 1
+ if len(bytes) > 1 {
+ bytes[1] |= 0x80
+ }
+ }
+ // Make the value odd since an even number this large certainly isn't prime.
+ bytes[len(bytes)-1] |= 1
+
+ p.SetBytes(bytes)
+ if p.ProbablyPrime(20) {
+ return p, nil
+ }
+ }
+}
+
+// Int returns a uniform random value in [0, max). It panics if max <= 0.
+func Int(rand io.Reader, max *big.Int) (n *big.Int, err error) {
+ if max.Sign() <= 0 {
+ panic("crypto/rand: argument to Int is <= 0")
+ }
+ n = new(big.Int)
+ n.Sub(max, n.SetUint64(1))
+ // bitLen is the maximum bit length needed to encode a value < max.
+ bitLen := n.BitLen()
+ if bitLen == 0 {
+ // the only valid result is 0
+ return
+ }
+ // k is the maximum byte length needed to encode a value < max.
+ k := (bitLen + 7) / 8
+ // b is the number of bits in the most significant byte of max-1.
+ b := uint(bitLen % 8)
+ if b == 0 {
+ b = 8
+ }
+
+ bytes := make([]byte, k)
+
+ for {
+ _, err = io.ReadFull(rand, bytes)
+ if err != nil {
+ return nil, err
+ }
+
+ // Clear bits in the first byte to increase the probability
+ // that the candidate is < max.
+ bytes[0] &= uint8(int(1<<b) - 1)
+
+ n.SetBytes(bytes)
+ if n.Cmp(max) < 0 {
+ return
+ }
+ }
+}
diff --git a/src/crypto/rand/util_test.go b/src/crypto/rand/util_test.go
new file mode 100644
index 0000000..9caf8e9
--- /dev/null
+++ b/src/crypto/rand/util_test.go
@@ -0,0 +1,149 @@
+// Copyright 2013 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 rand_test
+
+import (
+ "bytes"
+ "crypto/rand"
+ "fmt"
+ "io"
+ "math/big"
+ mathrand "math/rand"
+ "testing"
+ "time"
+)
+
+// https://golang.org/issue/6849.
+func TestPrimeSmall(t *testing.T) {
+ for n := 2; n < 10; n++ {
+ p, err := rand.Prime(rand.Reader, n)
+ if err != nil {
+ t.Fatalf("Can't generate %d-bit prime: %v", n, err)
+ }
+ if p.BitLen() != n {
+ t.Fatalf("%v is not %d-bit", p, n)
+ }
+ if !p.ProbablyPrime(32) {
+ t.Fatalf("%v is not prime", p)
+ }
+ }
+}
+
+// Test that passing bits < 2 causes Prime to return nil, error
+func TestPrimeBitsLt2(t *testing.T) {
+ if p, err := rand.Prime(rand.Reader, 1); p != nil || err == nil {
+ t.Errorf("Prime should return nil, error when called with bits < 2")
+ }
+}
+
+func TestPrimeNondeterministic(t *testing.T) {
+ r := mathrand.New(mathrand.NewSource(42))
+ p0, err := rand.Prime(r, 32)
+ if err != nil {
+ t.Fatal(err)
+ }
+ for i := 0; i < 128; i++ {
+ r.Seed(42)
+ p, err := rand.Prime(r, 32)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if p.Cmp(p0) != 0 {
+ return
+ }
+ }
+ t.Error("Prime always generated the same prime given the same input")
+}
+
+func TestInt(t *testing.T) {
+ // start at 128 so the case of (max.BitLen() % 8) == 0 is covered
+ for n := 128; n < 140; n++ {
+ b := new(big.Int).SetInt64(int64(n))
+ if i, err := rand.Int(rand.Reader, b); err != nil {
+ t.Fatalf("Can't generate random value: %v, %v", i, err)
+ }
+ }
+}
+
+type countingReader struct {
+ r io.Reader
+ n int
+}
+
+func (r *countingReader) Read(p []byte) (n int, err error) {
+ n, err = r.r.Read(p)
+ r.n += n
+ return n, err
+}
+
+// Test that Int reads only the necessary number of bytes from the reader for
+// max at each bit length
+func TestIntReads(t *testing.T) {
+ for i := 0; i < 32; i++ {
+ max := int64(1 << uint64(i))
+ t.Run(fmt.Sprintf("max=%d", max), func(t *testing.T) {
+ reader := &countingReader{r: rand.Reader}
+
+ _, err := rand.Int(reader, big.NewInt(max))
+ if err != nil {
+ t.Fatalf("Can't generate random value: %d, %v", max, err)
+ }
+ expected := (i + 7) / 8
+ if reader.n != expected {
+ t.Errorf("Int(reader, %d) should read %d bytes, but it read: %d", max, expected, reader.n)
+ }
+ })
+ }
+}
+
+// Test that Int does not mask out valid return values
+func TestIntMask(t *testing.T) {
+ for max := 1; max <= 256; max++ {
+ t.Run(fmt.Sprintf("max=%d", max), func(t *testing.T) {
+ for i := 0; i < max; i++ {
+ if testing.Short() && i == 0 {
+ i = max - 1
+ }
+ var b bytes.Buffer
+ b.WriteByte(byte(i))
+ n, err := rand.Int(&b, big.NewInt(int64(max)))
+ if err != nil {
+ t.Fatalf("Can't generate random value: %d, %v", max, err)
+ }
+ if n.Int64() != int64(i) {
+ t.Errorf("Int(reader, %d) should have returned value of %d, but it returned: %v", max, i, n)
+ }
+ }
+ })
+ }
+}
+
+func testIntPanics(t *testing.T, b *big.Int) {
+ defer func() {
+ if err := recover(); err == nil {
+ t.Errorf("Int should panic when called with max <= 0: %v", b)
+ }
+ }()
+ rand.Int(rand.Reader, b)
+}
+
+// Test that passing a new big.Int as max causes Int to panic
+func TestIntEmptyMaxPanics(t *testing.T) {
+ b := new(big.Int)
+ testIntPanics(t, b)
+}
+
+// Test that passing a negative value as max causes Int to panic
+func TestIntNegativeMaxPanics(t *testing.T) {
+ b := new(big.Int).SetInt64(int64(-1))
+ testIntPanics(t, b)
+}
+
+func BenchmarkPrime(b *testing.B) {
+ r := mathrand.New(mathrand.NewSource(time.Now().UnixNano()))
+ for i := 0; i < b.N; i++ {
+ rand.Prime(r, 1024)
+ }
+}