Implement SDCTR modes, as defined in the newmodes draft. This adds

[u/mdw/putty] / sshblowf.c

diff --git a/sshblowf.c b/sshblowf.c
index 9cbeed4..650f9b9 100644 (file)
--- a/sshblowf.c
+++ b/sshblowf.c
@@ -413,6 +413,32 @@ static void blowfish_msb_decrypt_cbc(unsigned char *blk, int len,
     ctx->iv1 = iv1;
 }
 
+static void blowfish_msb_sdctr(unsigned char *blk, int len,
+                                    BlowfishContext * ctx)
+{
+    word32 b[2], iv0, iv1, tmp;
+
+    assert((len & 7) == 0);
+
+    iv0 = ctx->iv0;
+    iv1 = ctx->iv1;
+
+    while (len > 0) {
+       blowfish_encrypt(iv0, iv1, b, ctx);
+       tmp = GET_32BIT_MSB_FIRST(blk);
+       PUT_32BIT_MSB_FIRST(blk, tmp ^ b[0]);
+       tmp = GET_32BIT_MSB_FIRST(blk + 4);
+       PUT_32BIT_MSB_FIRST(blk + 4, tmp ^ b[1]);
+       if ((iv0 = (iv0 + 1) & 0xffffffff) == 0)
+           iv1 = (iv1 + 1) & 0xffffffff;
+       blk += 8;
+       len -= 8;
+    }
+
+    ctx->iv0 = iv0;
+    ctx->iv1 = iv1;
+}
+
 static void blowfish_setkey(BlowfishContext * ctx,
                            const unsigned char *key, short keybytes)
 {
@@ -498,6 +524,12 @@ static void blowfish_key(void *handle, unsigned char *key)
     blowfish_setkey(ctx, key, 16);
 }
 
+static void blowfish256_key(void *handle, unsigned char *key)
+{
+    BlowfishContext *ctx = (BlowfishContext *)handle;
+    blowfish_setkey(ctx, key, 32);
+}
+
 static void blowfish_iv(void *handle, unsigned char *key)
 {
     BlowfishContext *ctx = (BlowfishContext *)handle;
@@ -542,20 +574,41 @@ static void blowfish_ssh2_decrypt_blk(void *handle, unsigned char *blk,
     blowfish_msb_decrypt_cbc(blk, len, ctx);
 }
 
+static void blowfish_ssh2_sdctr(void *handle, unsigned char *blk,
+                                     int len)
+{
+    BlowfishContext *ctx = (BlowfishContext *)handle;
+    blowfish_msb_sdctr(blk, len, ctx);
+}
+
 const struct ssh_cipher ssh_blowfish_ssh1 = {
     blowfish_ssh1_make_context, blowfish_free_context, blowfish_sesskey,
     blowfish_ssh1_encrypt_blk, blowfish_ssh1_decrypt_blk,
-    8, "Blowfish"
+    8, "Blowfish-128 CBC"
 };
 
 static const struct ssh2_cipher ssh_blowfish_ssh2 = {
     blowfish_make_context, blowfish_free_context, blowfish_iv, blowfish_key,
     blowfish_ssh2_encrypt_blk, blowfish_ssh2_decrypt_blk,
     "blowfish-cbc",
-    8, 128, "Blowfish"
+    8, 128, "Blowfish-128 CBC"
 };
 
+static const struct ssh2_cipher ssh_blowfish_ssh2_ctr = {
+    blowfish_make_context, blowfish_free_context, blowfish_iv, blowfish256_key,
+    blowfish_ssh2_sdctr, blowfish_ssh2_sdctr,
+    "blowfish-ctr",
+    8, 256, "Blowfish-256 SDCTR"
+};
+
+/*
+ * "blowfish-ctr" is disabled because it hasn't had any interoperability
+ * testing, which is in turn because I couldn't find another implementation
+ * to test against.  Once it's been tested, it can be enabled in standard
+ * builds.
+ */
 static const struct ssh2_cipher *const blowfish_list[] = {
+/*  &ssh_blowfish_ssh2_ctr, */
     &ssh_blowfish_ssh2
 };