Use io.ReadFull in places where it is appropriate.

csrand/csrand.go

@@ -37,6 +37,7 @@ import (
 	cryptRand "crypto/rand"
 	"encoding/binary"
 	"fmt"
+	"io"
 	"math/rand"
 )
 
@@ -44,7 +45,7 @@ var (
 	csRandSourceInstance csRandSource
 
 	// CsRand is a math/rand instance backed by crypto/rand CSPRNG.
-	CsRand       = rand.New(csRandSourceInstance)
+	CsRand = rand.New(csRandSourceInstance)
 )
 
 type csRandSource struct {
@@ -85,13 +86,9 @@ func IntRange(min, max int) int {
 
 // Bytes fills the slice with random data.
 func Bytes(buf []byte) error {
-	n, err := cryptRand.Read(buf)
+	_, err := io.ReadFull(cryptRand.Reader, buf)
 	if err != nil {
-		// Yes, the go idiom is to check the length, but we panic() when it
-		// does not match because the system is screwed at that point.
 		return err
-	} else if n != len(buf) {
-		panic(fmt.Sprintf("Bytes: truncated rand.Read (%d, %d)", n, len(buf)))
 	}
 
 	return nil

framing/framing.go

@@ -240,12 +240,9 @@ func (decoder *Decoder) Decode(data []byte, frames *bytes.Buffer) (int, error) {
 
 		// Remove the length field from the buffer.
 		var obfsLen [lengthLength]byte
-		n, err := frames.Read(obfsLen[:])
+		_, err := io.ReadFull(frames, obfsLen[:])
 		if err != nil {
 			return 0, err
-		} else if n != lengthLength {
-			// Should *NEVER* happen, since at least 2 bytes exist.
-			panic(fmt.Sprintf("BUG: Failed to read obfuscated length: %d", n))
 		}
 
 		// Derive the nonce the peer used.
@@ -284,13 +281,9 @@ func (decoder *Decoder) Decode(data []byte, frames *bytes.Buffer) (int, error) {
 
 	// Unseal the frame.
 	var box [maxFrameLength]byte
-	n, err := frames.Read(box[:decoder.nextLength])
+	n, err := io.ReadFull(frames, box[:decoder.nextLength])
 	if err != nil {
 		return 0, err
-	} else if n != int(decoder.nextLength) {
-		// Should *NEVER* happen, since the length is checked.
-		panic(fmt.Sprintf("BUG: Failed to read secretbox, got %d, should have %d",
-			n, decoder.nextLength))
 	}
 	out, ok := secretbox.Open(data[:0], box[:n], &decoder.nextNonce, &decoder.key)
 	if !ok || decoder.nextLengthInvalid {