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-rw-r--r--curve.c281
1 files changed, 281 insertions, 0 deletions
diff --git a/curve.c b/curve.c
new file mode 100644
index 0000000..229cd76
--- /dev/null
+++ b/curve.c
@@ -0,0 +1,281 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2011 - 2013 Daniel Borkmann.
+ * Subject to the GPL, version 2.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <limits.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+
+#include "built_in.h"
+#include "xmalloc.h"
+#include "curve.h"
+#include "xutils.h"
+#include "xio.h"
+#include "die.h"
+#include "curvetun.h"
+#include "locking.h"
+#include "crypto_verify_32.h"
+#include "crypto_box_curve25519xsalsa20poly1305.h"
+#include "crypto_scalarmult_curve25519.h"
+
+#define crypto_box_beforenm crypto_box_curve25519xsalsa20poly1305_beforenm
+#define crypto_box_afternm crypto_box_curve25519xsalsa20poly1305_afternm
+#define crypto_box_open_afternm crypto_box_curve25519xsalsa20poly1305_open_afternm
+
+#define NONCE_LENGTH (sizeof(struct taia))
+#define NONCE_OFFSET (crypto_box_curve25519xsalsa20poly1305_NONCEBYTES - NONCE_LENGTH)
+
+void curve25519_selftest(void)
+{
+ int i;
+ unsigned char alicesk[32] = {
+ 0x77, 0x07, 0x6d, 0x0a, 0x73, 0x18, 0xa5, 0x7d,
+ 0x3c, 0x16, 0xc1, 0x72, 0x51, 0xb2, 0x66, 0x45,
+ 0xdf, 0x4c, 0x2f, 0x87, 0xeb, 0xc0, 0x99, 0x2a,
+ 0xb1, 0x77, 0xfb, 0xa5, 0x1d, 0xb9, 0x2c, 0x2a
+ };
+ unsigned char bobpk[32] = {
+ 0xde, 0x9e, 0xdb, 0x7d, 0x7b, 0x7d, 0xc1, 0xb4,
+ 0xd3, 0x5b, 0x61, 0xc2, 0xec, 0xe4, 0x35, 0x37,
+ 0x3f, 0x83, 0x43, 0xc8, 0x5b, 0x78, 0x67, 0x4d,
+ 0xad, 0xfc, 0x7e, 0x14, 0x6f, 0x88, 0x2b, 0x4f
+ };
+ unsigned char nonce[24] = {
+ 0x69, 0x69, 0x6e, 0xe9, 0x55, 0xb6, 0x2b, 0x73,
+ 0xcd, 0x62, 0xbd, 0xa8, 0x75, 0xfc, 0x73, 0xd6,
+ 0x82, 0x19, 0xe0, 0x03, 0x6b, 0x7a, 0x0b, 0x37
+ };
+ unsigned char m[163] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0xbe, 0x07, 0x5f, 0xc5, 0x3c, 0x81, 0xf2, 0xd5,
+ 0xcf, 0x14, 0x13, 0x16, 0xeb, 0xeb, 0x0c, 0x7b,
+ 0x52, 0x28, 0xc5, 0x2a, 0x4c, 0x62, 0xcb, 0xd4,
+ 0x4b, 0x66, 0x84, 0x9b, 0x64, 0x24, 0x4f, 0xfc,
+ 0xe5, 0xec, 0xba, 0xaf, 0x33, 0xbd, 0x75, 0x1a,
+ 0x1a, 0xc7, 0x28, 0xd4, 0x5e, 0x6c, 0x61, 0x29,
+ 0x6c, 0xdc, 0x3c, 0x01, 0x23, 0x35, 0x61, 0xf4,
+ 0x1d, 0xb6, 0x6c, 0xce, 0x31, 0x4a, 0xdb, 0x31,
+ 0x0e, 0x3b, 0xe8, 0x25, 0x0c, 0x46, 0xf0, 0x6d,
+ 0xce, 0xea, 0x3a, 0x7f, 0xa1, 0x34, 0x80, 0x57,
+ 0xe2, 0xf6, 0x55, 0x6a, 0xd6, 0xb1, 0x31, 0x8a,
+ 0x02, 0x4a, 0x83, 0x8f, 0x21, 0xaf, 0x1f, 0xde,
+ 0x04, 0x89, 0x77, 0xeb, 0x48, 0xf5, 0x9f, 0xfd,
+ 0x49, 0x24, 0xca, 0x1c, 0x60, 0x90, 0x2e, 0x52,
+ 0xf0, 0xa0, 0x89, 0xbc, 0x76, 0x89, 0x70, 0x40,
+ 0xe0, 0x82, 0xf9, 0x37, 0x76, 0x38, 0x48, 0x64,
+ 0x5e, 0x07, 0x05
+ };
+ unsigned char c[163];
+ unsigned char result[147] = {
+ 0xf3, 0xff, 0xc7, 0x70, 0x3f, 0x94, 0x00, 0xe5,
+ 0x2a, 0x7d, 0xfb, 0x4b, 0x3d, 0x33, 0x05, 0xd9,
+ 0x8e, 0x99, 0x3b, 0x9f, 0x48, 0x68, 0x12, 0x73,
+ 0xc2, 0x96, 0x50, 0xba, 0x32, 0xfc, 0x76, 0xce,
+ 0x48, 0x33, 0x2e, 0xa7, 0x16, 0x4d, 0x96, 0xa4,
+ 0x47, 0x6f, 0xb8, 0xc5, 0x31, 0xa1, 0x18, 0x6a,
+ 0xc0, 0xdf, 0xc1, 0x7c, 0x98, 0xdc, 0xe8, 0x7b,
+ 0x4d, 0xa7, 0xf0, 0x11, 0xec, 0x48, 0xc9, 0x72,
+ 0x71, 0xd2, 0xc2, 0x0f, 0x9b, 0x92, 0x8f, 0xe2,
+ 0x27, 0x0d, 0x6f, 0xb8, 0x63, 0xd5, 0x17, 0x38,
+ 0xb4, 0x8e, 0xee, 0xe3, 0x14, 0xa7, 0xcc, 0x8a,
+ 0xb9, 0x32, 0x16, 0x45, 0x48, 0xe5, 0x26, 0xae,
+ 0x90, 0x22, 0x43, 0x68, 0x51, 0x7a, 0xcf, 0xea,
+ 0xbd, 0x6b, 0xb3, 0x73, 0x2b, 0xc0, 0xe9, 0xda,
+ 0x99, 0x83, 0x2b, 0x61, 0xca, 0x01, 0xb6, 0xde,
+ 0x56, 0x24, 0x4a, 0x9e, 0x88, 0xd5, 0xf9, 0xb3,
+ 0x79, 0x73, 0xf6, 0x22, 0xa4, 0x3d, 0x14, 0xa6,
+ 0x59, 0x9b, 0x1f, 0x65, 0x4c, 0xb4, 0x5a, 0x74,
+ 0xe3, 0x55, 0xa5
+ };
+
+ bug_on(NONCE_LENGTH != 16);
+
+ crypto_box_curve25519xsalsa20poly1305(c, m, 163, nonce, bobpk, alicesk);
+
+ for (i = 16; i < 163; ++i) {
+ if (c[i] != result[i - 16])
+ panic("Crypto selftest failed! :-(\n");
+ }
+}
+
+int curve25519_pubkey_hexparse_32(unsigned char *bin, size_t blen,
+ const char *ascii, size_t alen)
+{
+ int ret = sscanf(ascii,
+ "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:"
+ "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:"
+ "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:"
+ "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx",
+ &bin[0], &bin[1], &bin[2], &bin[3], &bin[4],
+ &bin[5], &bin[6], &bin[7], &bin[8], &bin[9],
+ &bin[10], &bin[11], &bin[12], &bin[13], &bin[14],
+ &bin[15], &bin[16], &bin[17], &bin[18], &bin[19],
+ &bin[20], &bin[21], &bin[22], &bin[23], &bin[24],
+ &bin[25], &bin[26], &bin[27], &bin[28], &bin[29],
+ &bin[30], &bin[31]);
+ return ret == 32;
+}
+
+void curve25519_alloc_or_maybe_die(struct curve25519_struct *curve)
+{
+ curve->enc_buf_size = curve->dec_buf_size = TUNBUFF_SIZ;
+
+ curve->enc_buf = xmalloc_aligned(curve->enc_buf_size, 16);
+ curve->dec_buf = xmalloc_aligned(curve->dec_buf_size, 16);
+
+ spinlock_init(&curve->enc_lock);
+ spinlock_init(&curve->dec_lock);
+}
+
+void curve25519_free(void *curvep)
+{
+ struct curve25519_struct *curve = curvep;
+
+ memset(curve->enc_buf, 0, curve->enc_buf_size);
+ memset(curve->dec_buf, 0, curve->dec_buf_size);
+
+ xfree(curve->enc_buf);
+ xfree(curve->dec_buf);
+
+ spinlock_destroy(&curve->enc_lock);
+ spinlock_destroy(&curve->dec_lock);
+}
+
+int curve25519_proto_init(struct curve25519_proto *proto, unsigned char *pubkey_remote,
+ size_t len, char *home, int server)
+{
+ int fd;
+ ssize_t ret;
+ char path[PATH_MAX];
+ unsigned char secretkey_own[crypto_box_curve25519xsalsa20poly1305_SECRETKEYBYTES];
+ unsigned char publickey_own[crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES];
+
+ fmemset(secretkey_own, 0, sizeof(secretkey_own));
+ fmemset(publickey_own, 0, sizeof(publickey_own));
+
+ if (!pubkey_remote || len != sizeof(publickey_own))
+ return -EINVAL;
+
+ slprintf(path, sizeof(path), "%s/%s", home, FILE_PRIVKEY);
+ fd = open_or_die(path, O_RDONLY);
+
+ ret = read(fd, secretkey_own, sizeof(secretkey_own));
+ if (ret != sizeof(secretkey_own)) {
+ xmemset(secretkey_own, 0, sizeof(secretkey_own));
+ panic("Cannot read private key!\n");
+ }
+
+ close(fd);
+
+ crypto_scalarmult_curve25519_base(publickey_own, secretkey_own);
+
+ if (!crypto_verify_32(publickey_own, pubkey_remote)) {
+ xmemset(secretkey_own, 0, sizeof(secretkey_own));
+ xmemset(publickey_own, 0, sizeof(publickey_own));
+ panic("PANIC: remote end has same public key as you have!!!\n");
+ }
+
+ crypto_box_beforenm(proto->key, pubkey_remote, secretkey_own);
+
+ xmemset(proto->enonce, 0, sizeof(proto->enonce));
+ xmemset(proto->dnonce, 0, sizeof(proto->dnonce));
+
+ xmemset(secretkey_own, 0, sizeof(secretkey_own));
+ xmemset(publickey_own, 0, sizeof(publickey_own));
+
+ return 0;
+}
+
+ssize_t curve25519_encode(struct curve25519_struct *curve, struct curve25519_proto *proto,
+ unsigned char *plaintext, size_t size, unsigned char **chipertext)
+{
+ int ret, i;
+ ssize_t done = size;
+ struct taia packet_taia;
+
+ spinlock_lock(&curve->enc_lock);
+
+ if (unlikely(size > curve->enc_buf_size)) {
+ done = -ENOMEM;
+ goto out;
+ }
+
+ taia_now(&packet_taia);
+ taia_pack(proto->enonce + NONCE_OFFSET, &packet_taia);
+
+ memset(curve->enc_buf, 0, curve->enc_buf_size);
+ ret = crypto_box_afternm(curve->enc_buf, plaintext, size, proto->enonce, proto->key);
+ if (unlikely(ret)) {
+ done = -EIO;
+ goto out;
+ }
+
+ fmemcpy(curve->enc_buf + crypto_box_boxzerobytes - NONCE_LENGTH,
+ proto->enonce + NONCE_OFFSET, NONCE_LENGTH);
+
+ for (i = 0; i < crypto_box_boxzerobytes - NONCE_LENGTH; ++i)
+ curve->enc_buf[i] = (uint8_t) secrand();
+
+ (*chipertext) = curve->enc_buf;
+out:
+ spinlock_unlock(&curve->enc_lock);
+ return done;
+}
+
+ssize_t curve25519_decode(struct curve25519_struct *curve, struct curve25519_proto *proto,
+ unsigned char *chipertext, size_t size, unsigned char **plaintext,
+ struct taia *arrival_taia)
+{
+ int ret;
+ ssize_t done = size;
+ struct taia packet_taia, arrival_taia2;
+
+ spinlock_lock(&curve->dec_lock);
+
+ if (unlikely(size > curve->dec_buf_size)) {
+ done = -ENOMEM;
+ goto out;
+ }
+ if (unlikely(size < crypto_box_boxzerobytes + NONCE_LENGTH)) {
+ done = 0;
+ goto out;
+ }
+ if (arrival_taia == NULL) {
+ taia_now(&arrival_taia2);
+ arrival_taia = &arrival_taia2;
+ }
+
+ taia_unpack(chipertext + crypto_box_boxzerobytes - NONCE_LENGTH, &packet_taia);
+ if (is_good_taia(arrival_taia, &packet_taia) == 0) {
+ syslog(LOG_ERR, "Bad packet time! Dropping connection!\n");
+ done = 0;
+ goto out;
+ }
+
+ memcpy(proto->dnonce + NONCE_OFFSET, chipertext + crypto_box_boxzerobytes - NONCE_LENGTH, NONCE_LENGTH);
+ memset(curve->dec_buf, 0, curve->dec_buf_size);
+
+ ret = crypto_box_open_afternm(curve->dec_buf, chipertext, size, proto->dnonce, proto->key);
+ if (unlikely(ret)) {
+ done = -EIO;
+ goto out;
+ }
+
+ (*plaintext) = curve->dec_buf;
+out:
+ spinlock_unlock(&curve->dec_lock);
+ return done;
+}
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