tls: format and send CLIENT_KEY_EXCHANGE

$ ./busybox tls kernel.org
insize:0 tail:0
got block len:74
got HANDSHAKE
got SERVER_HELLO
insize:79 tail:4265
got block len:4392
got HANDSHAKE
got CERTIFICATE
entered der @0x8b217a7:0x30 len:1452 inner_byte @0x8b217ab:0x30
entered der @0x8b217ab:0x30 len:1172 inner_byte @0x8b217af:0xa0
skipped der 0xa0, next byte 0x02
skipped der 0x02, next byte 0x30
skipped der 0x30, next byte 0x30
skipped der 0x30, next byte 0x30
skipped der 0x30, next byte 0x30
skipped der 0x30, next byte 0x30
entered der @0x8b218b4:0x30 len:418 inner_byte @0x8b218b8:0x30
skipped der 0x30, next byte 0x03
entered der @0x8b218c7:0x03 len:399 inner_byte @0x8b218cb:0x00
key bytes:399, first:0x00
entered der @0x8b218cc:0x30 len:394 inner_byte @0x8b218d0:0x02
binary bytes:385, first:0x00
skipped der 0x02, next byte 0x02
binary bytes:3, first:0x01
server_rsa_pub_key.size:384
insize:4397 tail:9
got block len:4
got SERVER_HELLO_DONE
insize:9 tail:0
^C

Next step: send CHANGE_CIPHER_SPEC... and actually implement it.

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

1 files changed, 203 insertions, 0 deletions

diff --git a/networking/tls_rsa.c b/networking/tls_rsa.c
new file mode 100644
index 0000000..058b09c
--- /dev/null
+++ b/networking/tls_rsa.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) 2017 Denys Vlasenko
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+#include "tls.h"
+
+#define pkcs1Pad(in, inlen, out, outlen, cryptType, userPtr) \
+        pkcs1Pad(in, inlen, out, outlen, cryptType)
+static ///bbox
+int32 pkcs1Pad(unsigned char *in, uint32 inlen, unsigned char *out,
+                                           uint32 outlen, int32 cryptType, void *userPtr)
+{
+        unsigned char   *c;
+        int32           randomLen;
+
+        randomLen = outlen - 3 - inlen;
+        if (randomLen < 8) {
+                psTraceCrypto("pkcs1Pad failure\n");
+                return PS_LIMIT_FAIL;
+        }
+        c = out;
+        *c = 0x00;
+        c++;
+        *c = (unsigned char)cryptType;
+        c++;
+        if (cryptType == PUBKEY_TYPE) {
+                while (randomLen-- > 0) {
+                        *c++ = 0xFF;
+                }
+        } else {
+                if (matrixCryptoGetPrngData(c, (uint32)randomLen, userPtr) < 0) {
+                        return PS_PLATFORM_FAIL;
+                }
+/*
+                SECURITY:  Read through the random data and change all 0x0 to 0x01.
+                This is per spec that no random bytes should be 0
+*/
+                while (randomLen-- > 0) {
+                        if (*c == 0x0) {
+                                *c = 0x01;
+                        }
+                        c++;
+                }
+        }
+        *c = 0x00;
+        c++;
+        memcpy(c, in, inlen);
+
+        return outlen;
+}
+
+#define psRsaCrypt(pool, in, inlen, out, outlen, key, type, data) \
+        psRsaCrypt(pool, in, inlen, out, outlen, key, type)
+static ///bbox
+int32 psRsaCrypt(psPool_t *pool, const unsigned char *in, uint32 inlen,
+			unsigned char *out, uint32 *outlen,	psRsaKey_t *key, int32 type,
+			void *data)
+{
+	pstm_int		tmp, tmpa, tmpb;
+	int32			res;
+	uint32			x;
+
+	if (in == NULL || out == NULL || outlen == NULL || key == NULL) {
+		psTraceCrypto("NULL parameter error in psRsaCrypt\n");
+		return PS_ARG_FAIL;
+	}
+
+	tmp.dp = tmpa.dp = tmpb.dp = NULL;
+
+	/* Init and copy into tmp */
+	if (pstm_init_for_read_unsigned_bin(pool, &tmp, inlen + sizeof(pstm_digit))
+			!= PS_SUCCESS) {
+		return PS_FAILURE;
+	}
+	if (pstm_read_unsigned_bin(&tmp, (unsigned char *)in, inlen) != PS_SUCCESS){
+		pstm_clear(&tmp);
+		return PS_FAILURE;
+	}
+	/* Sanity check on the input */
+	if (pstm_cmp(&key->N, &tmp) == PSTM_LT) {
+		res = PS_LIMIT_FAIL;
+		goto done;
+	}
+	if (type == PRIVKEY_TYPE) {
+		if (key->optimized) {
+			if (pstm_init_size(pool, &tmpa, key->p.alloc) != PS_SUCCESS) {
+				res = PS_FAILURE;
+				goto done;
+			}
+			if (pstm_init_size(pool, &tmpb, key->q.alloc) != PS_SUCCESS) {
+				pstm_clear(&tmpa);
+				res = PS_FAILURE;
+				goto done;
+			}
+			if (pstm_exptmod(pool, &tmp, &key->dP, &key->p, &tmpa) !=
+					PS_SUCCESS) {
+				psTraceCrypto("decrypt error: pstm_exptmod dP, p\n");
+				goto error;
+			}
+			if (pstm_exptmod(pool, &tmp, &key->dQ, &key->q, &tmpb) !=
+					PS_SUCCESS) {
+				psTraceCrypto("decrypt error: pstm_exptmod dQ, q\n");
+				goto error;
+			}
+			if (pstm_sub(&tmpa, &tmpb, &tmp) != PS_SUCCESS) {
+				psTraceCrypto("decrypt error: sub tmpb, tmp\n");
+				goto error;
+			}
+			if (pstm_mulmod(pool, &tmp, &key->qP, &key->p, &tmp) != PS_SUCCESS) {
+				psTraceCrypto("decrypt error: pstm_mulmod qP, p\n");
+				goto error;
+			}
+			if (pstm_mul_comba(pool, &tmp, &key->q, &tmp, NULL, 0)
+					!= PS_SUCCESS){
+				psTraceCrypto("decrypt error: pstm_mul q \n");
+				goto error;
+			}
+			if (pstm_add(&tmp, &tmpb, &tmp) != PS_SUCCESS) {
+				psTraceCrypto("decrypt error: pstm_add tmp \n");
+				goto error;
+			}
+		} else {
+			if (pstm_exptmod(pool, &tmp, &key->d, &key->N, &tmp) !=
+					PS_SUCCESS) {
+				psTraceCrypto("psRsaCrypt error: pstm_exptmod\n");
+				goto error;
+			}
+		}
+	} else if (type == PUBKEY_TYPE) {
+		if (pstm_exptmod(pool, &tmp, &key->e, &key->N, &tmp) != PS_SUCCESS) {
+			psTraceCrypto("psRsaCrypt error: pstm_exptmod\n");
+			goto error;
+		}
+	} else {
+		psTraceCrypto("psRsaCrypt error: invalid type param\n");
+		goto error;
+	}
+	/* Read it back */
+	x = pstm_unsigned_bin_size(&key->N);
+
+	if ((uint32)x > *outlen) {
+		res = -1;
+		psTraceCrypto("psRsaCrypt error: pstm_unsigned_bin_size\n");
+		goto done;
+	}
+	/* We want the encrypted value to always be the key size.  Pad with 0x0 */
+	while ((uint32)x < (unsigned long)key->size) {
+		*out++ = 0x0;
+		x++;
+	}
+
+	*outlen = x;
+	/* Convert it */
+	memset(out, 0x0, x);
+
+	if (pstm_to_unsigned_bin(pool, &tmp, out+(x-pstm_unsigned_bin_size(&tmp)))
+			!= PS_SUCCESS) {
+		psTraceCrypto("psRsaCrypt error: pstm_to_unsigned_bin\n");
+		goto error;
+	}
+	/* Clean up and return */
+	res = PS_SUCCESS;
+	goto done;
+error:
+	res = PS_FAILURE;
+done:
+	if (type == PRIVKEY_TYPE && key->optimized) {
+		pstm_clear_multi(&tmpa, &tmpb, NULL, NULL, NULL, NULL, NULL, NULL);
+	}
+	pstm_clear(&tmp);
+	return res;
+}
+
+int32 psRsaEncryptPub(psPool_t *pool, psRsaKey_t *key,
+                                                unsigned char *in, uint32 inlen,
+                                                unsigned char *out, uint32 outlen, void *data)
+{
+        int32   err;
+        uint32  size;
+
+        size = key->size;
+        if (outlen < size) {
+                psTraceCrypto("Error on bad outlen parameter to psRsaEncryptPub\n");
+                return PS_ARG_FAIL;
+        }
+
+        if ((err = pkcs1Pad(in, inlen, out, size, PRIVKEY_TYPE, data))
+                        < PS_SUCCESS) {
+                psTraceCrypto("Error padding psRsaEncryptPub. Likely data too long\n");
+                return err;
+        }
+        if ((err = psRsaCrypt(pool, out, size, out, (uint32*)&outlen, key,
+                        PUBKEY_TYPE, data)) < PS_SUCCESS) {
+                psTraceCrypto("Error performing psRsaEncryptPub\n");
+                return err;
+        }
+        if (outlen != size) {
+                psTraceCrypto("Encrypted size error in psRsaEncryptPub\n");
+                return PS_FAILURE;
+        }
+        return size;
+}