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sphinx: Kill read_buffer with fire 🔥

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Suggested-by: Rusty Russell <@rustyrussell>
Signed-off-by: Christian Decker <@cdecker>
This commit is contained in:
Christian Decker 2020-03-03 18:15:55 +01:00 • committed by Rusty Russell
parent e79cda8c9a
commit 6dd14a2039
2 changed files with 21 additions and 32 deletions
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52
common/sphinx.c
View file

@ -17,6 +17,8 @@
#include <sodium/crypto_auth_hmacsha256.h>
#include <sodium/crypto_stream_chacha20.h>
#include <wire/wire.h>
#define BLINDING_FACTOR_SIZE 32
#define KEY_LEN 32
@ -130,15 +132,6 @@ static void write_buffer(u8 *dst, const void *src, const size_t len, int *pos)
*pos += len;
}
/* Read len bytes from the source at position pos into dst and update
* the position pos accordingly.
*/
static void read_buffer(void *dst, const u8 *src, const size_t len, int *pos)
{
memcpy(dst, src + *pos, len);
*pos += len;
}
u8 *serialize_onionpacket(
const tal_t *ctx,
const struct onionpacket *m)
@ -184,25 +177,25 @@ enum onion_type parse_onionpacket(const u8 *src,
const size_t srclen,
struct onionpacket *dest)
{
int p = 0;
u8 rawEphemeralkey[PUBKEY_CMPR_LEN];
const u8 *cursor = src;
size_t max = srclen;
assert(srclen == TOTAL_PACKET_SIZE);
read_buffer(&dest->version, src, 1, &p);
dest->version = fromwire_u8(&cursor, &max);
if (dest->version != 0x00) {
// FIXME add logging
return WIRE_INVALID_ONION_VERSION;
}
read_buffer(rawEphemeralkey, src, sizeof(rawEphemeralkey), &p);
if (!pubkey_from_der(rawEphemeralkey, sizeof(rawEphemeralkey),
&dest->ephemeralkey)) {
fromwire_pubkey(&cursor, &max, &dest->ephemeralkey);
if (cursor == NULL) {
return WIRE_INVALID_ONION_KEY;
}
read_buffer(&dest->routinginfo, src, ROUTING_INFO_SIZE, &p);
read_buffer(&dest->mac, src, HMAC_SIZE, &p);
fromwire_u8_array(&cursor, &max, dest->routinginfo, ROUTING_INFO_SIZE);
fromwire_u8_array(&cursor, &max, dest->mac, HMAC_SIZE);
assert(max == 0);
return 0;
}
@ -853,29 +846,26 @@ u8 *sphinx_compressed_onion_serialize(const tal_t *ctx, const struct sphinx_comp
struct sphinx_compressed_onion *
sphinx_compressed_onion_deserialize(const tal_t *ctx, const u8 *src)
{
size_t srclen = tal_bytelen(src);
size_t routelen = srclen - VERSION_SIZE - PUBKEY_SIZE - HMAC_SIZE;
const u8 *cursor = src;
size_t max = tal_bytelen(src);
size_t routelen = max - VERSION_SIZE - PUBKEY_SIZE - HMAC_SIZE;
struct sphinx_compressed_onion *dst =
tal(ctx, struct sphinx_compressed_onion);
int p = 0;
u8 ephkey[PUBKEY_SIZE];
assert(srclen <= TOTAL_PACKET_SIZE);
/* This is not a compressed onion, so let's not parse it. */
if (routelen > ROUTING_INFO_SIZE)
return tal_free(dst);
read_buffer(&dst->version, src, 1, &p);
dst->version = fromwire_u8(&cursor, &max);
if (dst->version != 0x00)
return tal_free(dst);
read_buffer(ephkey, src, PUBKEY_SIZE, &p);
if (!pubkey_from_der(ephkey, PUBKEY_SIZE, &dst->ephemeralkey)) {
return tal_free(dst);
}
fromwire_pubkey(&cursor, &max, &dst->ephemeralkey);
dst->routinginfo = tal_arr(dst, u8, routelen);
read_buffer(dst->routinginfo, src, routelen, &p);
read_buffer(&dst->mac, src, HMAC_SIZE, &p);
assert(p == srclen);
fromwire_u8_array(&cursor, &max, dst->routinginfo, routelen);
fromwire_u8_array(&cursor, &max, dst->mac, HMAC_SIZE);
assert(max == 0);
return dst;
}

1
common/sphinx.h
View file

@ -10,7 +10,6 @@
#include <secp256k1.h>
#include <sodium/randombytes.h>
#include <wire/gen_onion_wire.h>
#include <wire/wire.h>
#define VERSION_SIZE 1
#define REALM_SIZE 1