[git commit] tls: massage writing for encryption support; finer-grained debug
Denys Vlasenko
vda.linux at googlemail.com
Wed Jan 18 05:45:50 UTC 2017
commit: https://git.busybox.net/busybox/commit/?id=c8ba23bcec94ecbc8ee82053d1b7e299cc839184
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
networking/tls.c | 69 +++++++++++++++++++++++++++++++-------------------------
1 file changed, 38 insertions(+), 31 deletions(-)
diff --git a/networking/tls.c b/networking/tls.c
index 8bcaee9..9d1a0fc 100644
--- a/networking/tls.c
+++ b/networking/tls.c
@@ -25,7 +25,9 @@
#include "tls.h"
-#define TLS_DEBUG 2
+#define TLS_DEBUG 1
+#define TLS_DEBUG_HASH 0
+#define TLS_DEBUG_DER 0
#if TLS_DEBUG
# define dbg(...) fprintf(stderr, __VA_ARGS__)
@@ -33,6 +35,12 @@
# define dbg(...) ((void)0)
#endif
+#if TLS_DEBUG_DER
+# define dbg_der(...) fprintf(stderr, __VA_ARGS__)
+#else
+# define dbg_der(...) ((void)0)
+#endif
+
#define RECORD_TYPE_CHANGE_CIPHER_SPEC 20
#define RECORD_TYPE_ALERT 21
#define RECORD_TYPE_HANDSHAKE 22
@@ -269,7 +277,7 @@ static void sha256_peek(sha256_ctx_t *ctx, void *buffer)
sha256_end(&ctx_copy, buffer);
}
-#if TLS_DEBUG >= 2
+#if TLS_DEBUG_HASH
static void sha256_hash_dbg(const char *fmt, sha256_ctx_t *ctx, const void *buffer, size_t len)
{
uint8_t h[SHA256_OUTSIZE];
@@ -283,7 +291,7 @@ static void sha256_hash_dbg(const char *fmt, sha256_ctx_t *ctx, const void *buff
#else
# define sha256_hash_dbg(fmt, ctx, buffer, len) \
sha256_hash(ctx, buffer, len)
-#endif /* not TLS_DEBUG >= 2 */
+#endif
// RFC 2104
// HMAC(key, text) based on a hash H (say, sha256) is:
@@ -424,8 +432,7 @@ static void prf_hmac_sha256(
#undef SEED
}
-static
-tls_state_t *new_tls_state(void)
+static tls_state_t *new_tls_state(void)
{
tls_state_t *tls = xzalloc(sizeof(*tls));
tls->fd = -1;
@@ -488,31 +495,31 @@ static void xwrite_and_hash(tls_state_t *tls, /*const*/ void *buf, unsigned size
uint8_t mac_hash[SHA256_OUTSIZE];
struct record_hdr *xhdr = buf;
- if (tls->encrypt_on_write) {
+ if (!tls->encrypt_on_write) {
+ xwrite(tls->fd, buf, size);
+ dbg("wrote %u bytes\n", size);
+ /* Handshake hash does not include record headers */
+ if (size > 5 && xhdr->type == RECORD_TYPE_HANDSHAKE) {
+ sha256_hash_dbg(">> sha256:%s", &tls->handshake_sha256_ctx, (uint8_t*)buf + 5, size - 5);
+ }
+ return;
+ }
+
//TODO: convert hmac_sha256 to precomputed
- hmac_sha256(mac_hash,
+ hmac_sha256(mac_hash,
tls->client_write_MAC_key, sizeof(tls->client_write_MAC_key),
&tls->write_seq64_be, sizeof(tls->write_seq64_be),
buf, size,
- NULL);
- tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be));
- /* Temporarily change for writing */
- xhdr->len16_lo += SHA256_OUTSIZE;
- }
+ NULL);
+ tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be));
+ xhdr->len16_lo += SHA256_OUTSIZE;
xwrite(tls->fd, buf, size);
+ xhdr->len16_lo -= SHA256_OUTSIZE;
dbg("wrote %u bytes\n", size);
- if (tls->encrypt_on_write) {
- xwrite(tls->fd, mac_hash, sizeof(mac_hash));
- dbg("wrote %u bytes of hash\n", (int)sizeof(mac_hash));
- xhdr->len16_lo -= SHA256_OUTSIZE;
- }
-
- /* Handshake hash does not include record headers */
- if (size > 5 && xhdr->type == RECORD_TYPE_HANDSHAKE) {
- sha256_hash_dbg(">> sha256:%s", &tls->handshake_sha256_ctx, (uint8_t*)buf + 5, size - 5);
- }
+ xwrite(tls->fd, mac_hash, sizeof(mac_hash));
+ dbg("wrote %u bytes of hash\n", (int)sizeof(mac_hash));
}
static int xread_tls_block(tls_state_t *tls)
@@ -611,7 +618,7 @@ static uint8_t *enter_der_item(uint8_t *der, uint8_t **endp)
{
uint8_t *new_der;
unsigned len = get_der_len(&new_der, der, *endp);
- dbg("entered der @%p:0x%02x len:%u inner_byte @%p:0x%02x\n", der, der[0], len, new_der, new_der[0]);
+ dbg_der("entered der @%p:0x%02x len:%u inner_byte @%p:0x%02x\n", der, der[0], len, new_der, new_der[0]);
/* Move "end" position to cover only this item */
*endp = new_der + len;
return new_der;
@@ -623,7 +630,7 @@ static uint8_t *skip_der_item(uint8_t *der, uint8_t *end)
unsigned len = get_der_len(&new_der, der, end);
/* Skip body */
new_der += len;
- dbg("skipped der 0x%02x, next byte 0x%02x\n", der[0], new_der[0]);
+ dbg_der("skipped der 0x%02x, next byte 0x%02x\n", der[0], new_der[0]);
return new_der;
}
@@ -632,7 +639,7 @@ static void der_binary_to_pstm(pstm_int *pstm_n, uint8_t *der, uint8_t *end)
uint8_t *bin_ptr;
unsigned len = get_der_len(&bin_ptr, der, end);
- dbg("binary bytes:%u, first:0x%02x\n", len, bin_ptr[0]);
+ dbg_der("binary bytes:%u, first:0x%02x\n", len, bin_ptr[0]);
pstm_init_for_read_unsigned_bin(/*pool:*/ NULL, pstm_n, len);
pstm_read_unsigned_bin(pstm_n, bin_ptr, len);
//return bin + len;
@@ -854,7 +861,7 @@ static void send_client_hello(tls_state_t *tls)
/* record.comprtypes[0] = 0; */
//dbg (make it repeatable): memset(record.rand32, 0x11, sizeof(record.rand32));
- dbg(">> HANDSHAKE_CLIENT_HELLO\n");
+ dbg(">> CLIENT_HELLO\n");
xwrite_and_hash(tls, &record, sizeof(record));
memcpy(tls->client_and_server_rand32, record.rand32, sizeof(record.rand32));
}
@@ -988,7 +995,7 @@ static void send_client_key_exchange(tls_state_t *tls)
record.xhdr.len16_hi = len >> 8;
record.xhdr.len16_lo = len & 0xff;
- dbg(">> HANDSHAKE_CLIENT_KEY_EXCHANGE\n");
+ dbg(">> CLIENT_KEY_EXCHANGE\n");
xwrite_and_hash(tls, &record, sizeof(record.xhdr) + len);
// RFC 5246
@@ -1114,13 +1121,13 @@ static void send_change_cipher_spec(tls_state_t *tls)
// includes all existing cipher suites.
static void send_client_finished(tls_state_t *tls)
{
- struct client_finished {
+ struct finished {
struct record_hdr xhdr;
uint8_t type;
uint8_t len24_hi, len24_mid, len24_lo;
uint8_t prf_result[12];
};
- struct client_finished record;
+ struct finished record;
uint8_t handshake_hash[SHA256_OUTSIZE];
fill_handshake_record_hdr(&record.xhdr, sizeof(record));
@@ -1134,13 +1141,13 @@ static void send_client_finished(tls_state_t *tls)
);
dump_hex("from secret: %s\n", tls->master_secret, sizeof(tls->master_secret));
dump_hex("from labelSeed: %s", "client finished", sizeof("client finished")-1);
- dump_hex("%s\n", handshake_hash, sizeof(handshake_hash));
+ dump_hex("%s\n", handshake_hash, sizeof(handshake_hash));
dump_hex("=> digest: %s\n", record.prf_result, sizeof(record.prf_result));
//(1) TODO: well, this should be encrypted on send, really.
//(2) do we really need to also hash it?
- dbg(">> HANDSHAKE_FINISHED\n");
+ dbg(">> FINISHED\n");
xwrite_and_hash(tls, &record, sizeof(record));
}
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