tls: add support for TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 cipher

function                                             old     new   delta
xwrite_encrypted                                     209     605    +396
GHASH                                                  -     395    +395
aes_encrypt_1                                          -     382    +382
GMULT                                                  -     192    +192
tls_xread_record                                     489     659    +170
aes_encrypt_one_block                                  -      65     +65
aesgcm_setkey                                          -      58     +58
FlattenSzInBits                                        -      52     +52
tls_handshake                                       1890    1941     +51
xwrite_and_update_handshake_hash                      46      81     +35
xorbuf                                                 -      24     +24
aes_setkey                                             -      16     +16
psRsaEncryptPub                                      413     421      +8
stty_main                                           1221    1227      +6
ssl_client_main                                      138     143      +5
next_token                                           841     845      +4
spawn_ssl_client                                     218     219      +1
volume_id_probe_hfs_hfsplus                          564     563      -1
read_package_field                                   232     230      -2
i2cdetect_main                                       674     672      -2
fail_hunk                                            139     136      -3
parse_expr                                           891     883      -8
curve25519                                           802     793      -9
aes_cbc_decrypt                                      971     958     -13
xwrite_handshake_record                               43       -     -43
aes_cbc_encrypt                                      644     172    -472
------------------------------------------------------------------------------
(add/remove: 9/1 grow/shrink: 9/8 up/down: 1860/-553)        Total: 1307 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 148 insertions, 0 deletions

diff --git a/networking/tls_aesgcm.c b/networking/tls_aesgcm.c
new file mode 100644
index 000000000..584cee98e
--- /dev/null
+++ b/networking/tls_aesgcm.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2018 Denys Vlasenko
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+
+#include "tls.h"
+
+typedef uint8_t byte;
+typedef uint32_t word32;
+#define XMEMSET memset
+#define XMEMCPY memcpy
+
+#define TLS_MAJ 3
+#define TLS_MIN 3
+#define RECHDR_LEN 5
+#define OUTBUF_PFX (8 + AES_BLOCK_SIZE)
+
+void FAST_FUNC xorbuf(void* buf, const void* mask, unsigned count)
+{
+    word32 i;
+    byte*       b = (byte*)buf;
+    const byte* m = (const byte*)mask;
+    for (i = 0; i < count; i++)
+        b[i] ^= m[i];
+}
+
+/* wolfssl-3.15.3/wolfcrypt/src/aes.c */
+
+static void FlattenSzInBits(byte* buf, word32 sz)
+{
+    /* Multiply the sz by 8 */
+    word32 szHi = (sz >> (8*sizeof(sz) - 3));
+    sz <<= 3;
+
+    /* copy over the words of the sz into the destination buffer */
+    buf[0] = (szHi >> 24) & 0xff;
+    buf[1] = (szHi >> 16) & 0xff;
+    buf[2] = (szHi >>  8) & 0xff;
+    buf[3] = szHi & 0xff;
+    buf[4] = (sz >> 24) & 0xff;
+    buf[5] = (sz >> 16) & 0xff;
+    buf[6] = (sz >>  8) & 0xff;
+    buf[7] = sz & 0xff;
+}
+
+static void RIGHTSHIFTX(byte* x)
+{
+    int i;
+    int carryOut = 0;
+    int carryIn = 0;
+    int borrow = x[15] & 0x01;
+
+    for (i = 0; i < AES_BLOCK_SIZE; i++) {
+        carryOut = x[i] & 0x01;
+        x[i] = (x[i] >> 1) | (carryIn ? 0x80 : 0);
+        carryIn = carryOut;
+    }
+    if (borrow) x[0] ^= 0xE1;
+}
+
+static void GMULT(byte* X, byte* Y)
+{
+    byte Z[AES_BLOCK_SIZE];
+    byte V[AES_BLOCK_SIZE];
+    int i, j;
+
+    XMEMSET(Z, 0, AES_BLOCK_SIZE);
+    XMEMCPY(V, X, AES_BLOCK_SIZE);
+    for (i = 0; i < AES_BLOCK_SIZE; i++)
+    {
+        byte y = Y[i];
+        for (j = 0; j < 8; j++)
+        {
+            if (y & 0x80) {
+                xorbuf(Z, V, AES_BLOCK_SIZE);
+            }
+
+            RIGHTSHIFTX(V);
+            y = y << 1;
+        }
+    }
+    XMEMCPY(X, Z, AES_BLOCK_SIZE);
+}
+
+void FAST_FUNC aesgcm_GHASH(byte* h, const byte* a, unsigned aSz, const byte* c,
+    unsigned cSz, byte* s, unsigned sSz)
+{
+    byte x[AES_BLOCK_SIZE];
+    byte scratch[AES_BLOCK_SIZE];
+    word32 blocks, partial;
+    //was: byte* h = aes->H;
+
+    XMEMSET(x, 0, AES_BLOCK_SIZE);
+
+    /* Hash in A, the Additional Authentication Data */
+    if (aSz != 0 && a != NULL) {
+        blocks = aSz / AES_BLOCK_SIZE;
+        partial = aSz % AES_BLOCK_SIZE;
+        while (blocks--) {
+            xorbuf(x, a, AES_BLOCK_SIZE);
+            GMULT(x, h);
+            a += AES_BLOCK_SIZE;
+        }
+        if (partial != 0) {
+            XMEMSET(scratch, 0, AES_BLOCK_SIZE);
+            XMEMCPY(scratch, a, partial);
+            xorbuf(x, scratch, AES_BLOCK_SIZE);
+            GMULT(x, h);
+        }
+    }
+
+    /* Hash in C, the Ciphertext */
+    if (cSz != 0 && c != NULL) {
+        blocks = cSz / AES_BLOCK_SIZE;
+        partial = cSz % AES_BLOCK_SIZE;
+        while (blocks--) {
+            xorbuf(x, c, AES_BLOCK_SIZE);
+            GMULT(x, h);
+            c += AES_BLOCK_SIZE;
+        }
+        if (partial != 0) {
+            XMEMSET(scratch, 0, AES_BLOCK_SIZE);
+            XMEMCPY(scratch, c, partial);
+            xorbuf(x, scratch, AES_BLOCK_SIZE);
+            GMULT(x, h);
+        }
+    }
+
+    /* Hash in the lengths of A and C in bits */
+    FlattenSzInBits(&scratch[0], aSz);
+    FlattenSzInBits(&scratch[8], cSz);
+    xorbuf(x, scratch, AES_BLOCK_SIZE);
+    GMULT(x, h);
+
+    /* Copy the result into s. */
+    XMEMCPY(s, x, sSz);
+}
+
+void FAST_FUNC aesgcm_setkey(uint8_t H[16], struct tls_aes *aes, const byte* key, unsigned len)
+{
+    byte iv[AES_BLOCK_SIZE];
+
+    aes_setkey(aes, key, len);
+
+    memset(iv, 0, AES_BLOCK_SIZE);
+    aes_encrypt_one_block(aes, iv, H);
+}