emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tls: massage writing for encryption support; finer-grained debug

Browse Source 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-01-18 06:45:50 +01:00
parent 5d1662ea1c
commit c8ba23bcec
1 changed files with 38 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
networking/tls.c
View File

@ -25,7 +25,9 @@
#include "tls.h" #include "tls.h"
#define TLS_DEBUG 2 #define TLS_DEBUG 1
#define TLS_DEBUG_HASH 0
#define TLS_DEBUG_DER 0
#if TLS_DEBUG #if TLS_DEBUG
# define dbg(...) fprintf(stderr, __VA_ARGS__) # define dbg(...) fprintf(stderr, __VA_ARGS__)
@ -33,6 +35,12 @@
# define dbg(...) ((void)0) # define dbg(...) ((void)0)
#endif #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_CHANGE_CIPHER_SPEC 20
#define RECORD_TYPE_ALERT 21 #define RECORD_TYPE_ALERT 21
#define RECORD_TYPE_HANDSHAKE 22 #define RECORD_TYPE_HANDSHAKE 22
@ -269,7 +277,7 @@ static void sha256_peek(sha256_ctx_t *ctx, void *buffer)
sha256_end(&ctx_copy, 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) static void sha256_hash_dbg(const char *fmt, sha256_ctx_t *ctx, const void *buffer, size_t len)
{ {
uint8_t h[SHA256_OUTSIZE]; 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 #else
# define sha256_hash_dbg(fmt, ctx, buffer, len) \ # define sha256_hash_dbg(fmt, ctx, buffer, len) \
sha256_hash(ctx, buffer, len) sha256_hash(ctx, buffer, len)
#endif /* not TLS_DEBUG >= 2 */ #endif
// RFC 2104 // RFC 2104
// HMAC(key, text) based on a hash H (say, sha256) is: // HMAC(key, text) based on a hash H (say, sha256) is:
@ -424,8 +432,7 @@ static void prf_hmac_sha256(
#undef SEED #undef SEED
} }
static static tls_state_t *new_tls_state(void)
tls_state_t *new_tls_state(void)
{ {
tls_state_t *tls = xzalloc(sizeof(*tls)); tls_state_t *tls = xzalloc(sizeof(*tls));
tls->fd = -1; 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]; uint8_t mac_hash[SHA256_OUTSIZE];
struct record_hdr *xhdr = buf; 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 //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->client_write_MAC_key, sizeof(tls->client_write_MAC_key),
&tls->write_seq64_be, sizeof(tls->write_seq64_be), &tls->write_seq64_be, sizeof(tls->write_seq64_be),
buf, size, buf, size,
NULL); NULL);
tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be)); tls->write_seq64_be = SWAP_BE64(1 + SWAP_BE64(tls->write_seq64_be));
/* Temporarily change for writing */
xhdr->len16_lo += SHA256_OUTSIZE;
}
xhdr->len16_lo += SHA256_OUTSIZE;
xwrite(tls->fd, buf, size); xwrite(tls->fd, buf, size);
xhdr->len16_lo -= SHA256_OUTSIZE;
dbg("wrote %u bytes\n", size); dbg("wrote %u bytes\n", size);
if (tls->encrypt_on_write) { xwrite(tls->fd, mac_hash, sizeof(mac_hash));
xwrite(tls->fd, mac_hash, sizeof(mac_hash)); dbg("wrote %u bytes of hash\n", (int)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);
}
} }
static int xread_tls_block(tls_state_t *tls) 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; uint8_t *new_der;
unsigned len = get_der_len(&new_der, der, *endp); 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 */ /* Move "end" position to cover only this item */
*endp = new_der + len; *endp = new_der + len;
return new_der; 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); unsigned len = get_der_len(&new_der, der, end);
/* Skip body */ /* Skip body */
new_der += len; 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; 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; uint8_t *bin_ptr;
unsigned len = get_der_len(&bin_ptr, der, end); 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_init_for_read_unsigned_bin(/*pool:*/ NULL, pstm_n, len);
pstm_read_unsigned_bin(pstm_n, bin_ptr, len); pstm_read_unsigned_bin(pstm_n, bin_ptr, len);
//return bin + len; //return bin + len;
@ -854,7 +861,7 @@ static void send_client_hello(tls_state_t *tls)
/* record.comprtypes[0] = 0; */ /* record.comprtypes[0] = 0; */
//dbg (make it repeatable): memset(record.rand32, 0x11, sizeof(record.rand32)); //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)); xwrite_and_hash(tls, &record, sizeof(record));
memcpy(tls->client_and_server_rand32, record.rand32, sizeof(record.rand32)); 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_hi = len >> 8;
record.xhdr.len16_lo = len & 0xff; 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); xwrite_and_hash(tls, &record, sizeof(record.xhdr) + len);
// RFC 5246 // RFC 5246
@ -1114,13 +1121,13 @@ static void send_change_cipher_spec(tls_state_t *tls)
// includes all existing cipher suites. // includes all existing cipher suites.
static void send_client_finished(tls_state_t *tls) static void send_client_finished(tls_state_t *tls)
{ {
struct client_finished { struct finished {
struct record_hdr xhdr; struct record_hdr xhdr;
uint8_t type; uint8_t type;
uint8_t len24_hi, len24_mid, len24_lo; uint8_t len24_hi, len24_mid, len24_lo;
uint8_t prf_result[12]; uint8_t prf_result[12];
}; };
struct client_finished record; struct finished record;
uint8_t handshake_hash[SHA256_OUTSIZE]; uint8_t handshake_hash[SHA256_OUTSIZE];
fill_handshake_record_hdr(&record.xhdr, sizeof(record)); 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 secret: %s\n", tls->master_secret, sizeof(tls->master_secret));
dump_hex("from labelSeed: %s", "client finished", sizeof("client finished")-1); 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)); dump_hex("=> digest: %s\n", record.prf_result, sizeof(record.prf_result));
//(1) TODO: well, this should be encrypted on send, really. //(1) TODO: well, this should be encrypted on send, really.
//(2) do we really need to also hash it? //(2) do we really need to also hash it?
dbg(">> HANDSHAKE_FINISHED\n"); dbg(">> FINISHED\n");
xwrite_and_hash(tls, &record, sizeof(record)); xwrite_and_hash(tls, &record, sizeof(record));
} }