crypto/cipher, crypto/rc4: make overlap rules wording consistent

Closes #21279

Change-Id: I84d6b168a684fa9f3c046028d0c9f00292d7c110
Reviewed-on: https://go-review.googlesource.com/61132
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/crypto/cipher/cipher.go b/src/crypto/cipher/cipher.go
index 0950ea9e80db867ba7f66c38fdf4a2fec1da3cc7..31c14d7f914a5dda334d85377372bb5450012794 100644 (file)
--- a/src/crypto/cipher/cipher.go
+++ b/src/crypto/cipher/cipher.go
@@ -17,18 +17,18 @@ type Block interface {
        BlockSize() int
 
        // Encrypt encrypts the first block in src into dst.
-       // Dst and src may point at the same memory.
+       // Dst and src must overlap entirely or not at all.
        Encrypt(dst, src []byte)
 
        // Decrypt decrypts the first block in src into dst.
-       // Dst and src may point at the same memory.
+       // Dst and src must overlap entirely or not at all.
        Decrypt(dst, src []byte)
 }
 
 // A Stream represents a stream cipher.
 type Stream interface {
        // XORKeyStream XORs each byte in the given slice with a byte from the
-       // cipher's key stream. Dst and src may point to the same memory.
+       // cipher's key stream. Dst and src must overlap entirely or not at all.
        //
        // If len(dst) < len(src), XORKeyStream should panic. It is acceptable
        // to pass a dst bigger than src, and in that case, XORKeyStream will
@@ -47,8 +47,8 @@ type BlockMode interface {
        BlockSize() int
 
        // CryptBlocks encrypts or decrypts a number of blocks. The length of
-       // src must be a multiple of the block size. Dst and src may point to
-       // the same memory.
+       // src must be a multiple of the block size. Dst and src must overlap
+       // entirely or not at all.
        //
        // If len(dst) < len(src), CryptBlocks should panic. It is acceptable
        // to pass a dst bigger than src, and in that case, CryptBlocks will

diff --git a/src/crypto/cipher/gcm.go b/src/crypto/cipher/gcm.go
index 62085aac0fe58b68bd4095fd24b3bc92823369b1..28f3ddd6e63474bcc0ccb38f2deb6a3ba7523949 100644 (file)
--- a/src/crypto/cipher/gcm.go
+++ b/src/crypto/cipher/gcm.go
@@ -26,7 +26,7 @@ type AEAD interface {
        // slice. The nonce must be NonceSize() bytes long and unique for all
        // time, for a given key.
        //
-       // The plaintext and dst may alias exactly or not at all. To reuse
+       // The plaintext and dst must overlap exactly or not at all. To reuse
        // plaintext's storage for the encrypted output, use plaintext[:0] as dst.
        Seal(dst, nonce, plaintext, additionalData []byte) []byte
 
@@ -36,7 +36,7 @@ type AEAD interface {
        // bytes long and both it and the additional data must match the
        // value passed to Seal.
        //
-       // The ciphertext and dst may alias exactly or not at all. To reuse
+       // The ciphertext and dst must overlap exactly or not at all. To reuse
        // ciphertext's storage for the decrypted output, use ciphertext[:0] as dst.
        //
        // Even if the function fails, the contents of dst, up to its capacity,

diff --git a/src/crypto/rc4/rc4.go b/src/crypto/rc4/rc4.go
index 772af0e7e0d4fdc5b9d38e18f04687dc38d3dcef..8274325c81a0ce72ee52243c65042a7d007a41e4 100644 (file)
--- a/src/crypto/rc4/rc4.go
+++ b/src/crypto/rc4/rc4.go
@@ -52,8 +52,7 @@ func (c *Cipher) Reset() {
 }
 
 // xorKeyStreamGeneric sets dst to the result of XORing src with the
-// key stream. Dst and src may be the same slice but otherwise should
-// not overlap.
+// key stream. Dst and src must overlap entirely or not at all.
 //
 // This is the pure Go version. rc4_{amd64,386,arm}* contain assembly
 // implementations. This is here for tests and to prevent bitrot.

diff --git a/src/crypto/rc4/rc4_asm.go b/src/crypto/rc4/rc4_asm.go
index 8d464547fa86d023859d996f959430e84578ee70..7e5f8b2fa40296fac1bb002ea3b39ecbd992f9e2 100644 (file)
--- a/src/crypto/rc4/rc4_asm.go
+++ b/src/crypto/rc4/rc4_asm.go
@@ -9,7 +9,7 @@ package rc4
 func xorKeyStream(dst, src *byte, n int, state *[256]uint32, i, j *uint8)
 
 // XORKeyStream sets dst to the result of XORing src with the key stream.
-// Dst and src may be the same slice but otherwise should not overlap.
+// Dst and src must overlap entirely or not at all.
 func (c *Cipher) XORKeyStream(dst, src []byte) {
        if len(src) == 0 {
                return

diff --git a/src/crypto/rc4/rc4_ref.go b/src/crypto/rc4/rc4_ref.go
index e34bd34cf1df90d7719b20ded5ab87da1a92d3bc..9b98fc49e7f291ebbd59a66320ef211e2d399469 100644 (file)
--- a/src/crypto/rc4/rc4_ref.go
+++ b/src/crypto/rc4/rc4_ref.go
@@ -7,7 +7,7 @@
 package rc4
 
 // XORKeyStream sets dst to the result of XORing src with the key stream.
-// Dst and src may be the same slice but otherwise should not overlap.
+// Dst and src must overlap entirely or not at all.
 func (c *Cipher) XORKeyStream(dst, src []byte) {
        c.xorKeyStreamGeneric(dst, src)
 }