3 files changed, 46 insertions, 7 deletions

diff --git a/src/lib/libcrypto/chacha/chacha-merged.c b/src/lib/libcrypto/chacha/chacha-merged.c
index 25092b16da..a665fb316f 100644
--- a/src/lib/libcrypto/chacha/chacha-merged.c
+++ b/src/lib/libcrypto/chacha/chacha-merged.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: chacha-merged.c,v 1.5 2014/06/24 17:48:30 jsing Exp $ */
+/* $OpenBSD: chacha-merged.c,v 1.6 2014/06/24 18:12:09 jsing Exp $ */
 /*
 chacha-merged.c version 20080118
 D. J. Bernstein
@@ -7,16 +7,18 @@ Public domain.
 
 #include <sys/types.h>
 
-struct chacha_ctx {
-        u_int input[16];
-};
-
 #define CHACHA_MINKEYLEN        16
 #define CHACHA_NONCELEN         8
 #define CHACHA_CTRLEN           8
 #define CHACHA_STATELEN         (CHACHA_NONCELEN+CHACHA_CTRLEN)
 #define CHACHA_BLOCKLEN         64
 
+struct chacha_ctx {
+        u_int input[16];
+        u_int8_t ks[CHACHA_BLOCKLEN];
+        u_int8_t unused;
+};
+
 static inline void chacha_keysetup(struct chacha_ctx *x, const u_char *k,
     u_int kbits)
     __attribute__((__bounded__(__minbytes__, 2, CHACHA_MINKEYLEN)));
@@ -187,6 +189,25 @@ chacha_encrypt_bytes(chacha_ctx *x, const u8 *m, u8 *c, u32 bytes)
                 x14 = PLUS(x14, j14);
                 x15 = PLUS(x15, j15);
 
+                if (bytes < 64) {
+                        U32TO8_LITTLE(x->ks + 0, x0);
+                        U32TO8_LITTLE(x->ks + 4, x1);
+                        U32TO8_LITTLE(x->ks + 8, x2);
+                        U32TO8_LITTLE(x->ks + 12, x3);
+                        U32TO8_LITTLE(x->ks + 16, x4);
+                        U32TO8_LITTLE(x->ks + 20, x5);
+                        U32TO8_LITTLE(x->ks + 24, x6);
+                        U32TO8_LITTLE(x->ks + 28, x7);
+                        U32TO8_LITTLE(x->ks + 32, x8);
+                        U32TO8_LITTLE(x->ks + 36, x9);
+                        U32TO8_LITTLE(x->ks + 40, x10);
+                        U32TO8_LITTLE(x->ks + 44, x11);
+                        U32TO8_LITTLE(x->ks + 48, x12);
+                        U32TO8_LITTLE(x->ks + 52, x13);
+                        U32TO8_LITTLE(x->ks + 56, x14);
+                        U32TO8_LITTLE(x->ks + 60, x15);
+                }
+
                 x0 = XOR(x0, U8TO32_LITTLE(m + 0));
                 x1 = XOR(x1, U8TO32_LITTLE(m + 4));
                 x2 = XOR(x2, U8TO32_LITTLE(m + 8));
@@ -237,6 +258,7 @@ chacha_encrypt_bytes(chacha_ctx *x, const u8 *m, u8 *c, u32 bytes)
                         }
                         x->input[12] = j12;
                         x->input[13] = j13;
+                        x->unused = 64 - bytes;
                         return;
                 }
                 bytes -= 64;
diff --git a/src/lib/libcrypto/chacha/chacha.c b/src/lib/libcrypto/chacha/chacha.c
index a12c824fe6..141b3e99f6 100644
--- a/src/lib/libcrypto/chacha/chacha.c
+++ b/src/lib/libcrypto/chacha/chacha.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: chacha.c,v 1.4 2014/06/12 15:49:28 deraadt Exp $ */
+/* $OpenBSD: chacha.c,v 1.5 2014/06/24 18:12:09 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -22,6 +22,7 @@ void
 ChaCha_set_key(ChaCha_ctx *ctx, const unsigned char *key, uint32_t keybits)
 {
         chacha_keysetup((chacha_ctx *)ctx, key, keybits);
+        ctx->unused = 0;
 }
 
 void
@@ -29,11 +30,25 @@ ChaCha_set_iv(ChaCha_ctx *ctx, const unsigned char *iv,
     const unsigned char *counter)
 {
         chacha_ivsetup((chacha_ctx *)ctx, iv, counter);
+        ctx->unused = 0;
 }
 
 void
 ChaCha(ChaCha_ctx *ctx, unsigned char *out, const unsigned char *in, size_t len)
 {
+        unsigned char *k;
+        int i, l;
+
+        /* Consume remaining keystream, if any exists. */
+        if (ctx->unused > 0) {
+                k = ctx->ks + 64 - ctx->unused;
+                l = (len > ctx->unused) ? ctx->unused : len;
+                for (i = 0; i < l; i++)
+                        *(out++) = *(in++) ^ *(k++);
+                ctx->unused -= l;
+                len -= l;
+        }
+
         chacha_encrypt_bytes((chacha_ctx *)ctx, in, out, (uint32_t)len);
 }
 
diff --git a/src/lib/libcrypto/chacha/chacha.h b/src/lib/libcrypto/chacha/chacha.h
index 636770ad99..a221825d9e 100644
--- a/src/lib/libcrypto/chacha/chacha.h
+++ b/src/lib/libcrypto/chacha/chacha.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: chacha.h,v 1.4 2014/06/12 15:49:28 deraadt Exp $ */
+/* $OpenBSD: chacha.h,v 1.5 2014/06/24 18:12:09 jsing Exp $ */
 /*
  * Copyright (c) Joel Sing <jsing@openbsd.org>
  *
@@ -32,6 +32,8 @@ extern "C" {
 
 typedef struct {
         unsigned int input[16];
+        unsigned char ks[64];
+        unsigned char unused;
 } ChaCha_ctx;
 
 void ChaCha_set_key(ChaCha_ctx *ctx, const unsigned char *key,