openssl/crypto/packet.c

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/*
* Copyright 2015-2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/cryptlib.h"
#include "internal/packet.h"
#if !defined OPENSSL_NO_QUIC && !defined FIPS_MODULE
# include "internal/packet_quic.h"
#endif
#include <openssl/err.h>
#define DEFAULT_BUF_SIZE 256
int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
{
if (!WPACKET_reserve_bytes(pkt, len, allocbytes))
return 0;
pkt->written += len;
pkt->curr += len;
return 1;
}
int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,
unsigned char **allocbytes, size_t lenbytes)
{
if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
|| !WPACKET_allocate_bytes(pkt, len, allocbytes)
|| !WPACKET_close(pkt))
return 0;
return 1;
}
#define GETBUF(p) (((p)->staticbuf != NULL) \
? (p)->staticbuf \
: ((p)->buf != NULL \
? (unsigned char *)(p)->buf->data \
: NULL))
int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
{
/* Internal API, so should not fail */
if (!ossl_assert(pkt->subs != NULL && len != 0))
return 0;
if (pkt->maxsize - pkt->written < len)
return 0;
if (pkt->buf != NULL && (pkt->buf->length - pkt->written < len)) {
size_t newlen;
size_t reflen;
reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
if (reflen > SIZE_MAX / 2) {
newlen = SIZE_MAX;
} else {
newlen = reflen * 2;
if (newlen < DEFAULT_BUF_SIZE)
newlen = DEFAULT_BUF_SIZE;
}
if (BUF_MEM_grow(pkt->buf, newlen) == 0)
return 0;
}
if (allocbytes != NULL) {
*allocbytes = WPACKET_get_curr(pkt);
if (pkt->endfirst && *allocbytes != NULL)
*allocbytes -= len;
}
return 1;
}
int WPACKET_sub_reserve_bytes__(WPACKET *pkt, size_t len,
unsigned char **allocbytes, size_t lenbytes)
{
if (pkt->endfirst && lenbytes > 0)
return 0;
if (!WPACKET_reserve_bytes(pkt, lenbytes + len, allocbytes))
return 0;
if (*allocbytes != NULL)
*allocbytes += lenbytes;
return 1;
}
static size_t maxmaxsize(size_t lenbytes)
{
if (lenbytes >= sizeof(size_t) || lenbytes == 0)
return SIZE_MAX;
return ((size_t)1 << (lenbytes * 8)) - 1 + lenbytes;
}
static int wpacket_intern_init_len(WPACKET *pkt, size_t lenbytes)
{
unsigned char *lenchars;
pkt->curr = 0;
pkt->written = 0;
if ((pkt->subs = OPENSSL_zalloc(sizeof(*pkt->subs))) == NULL)
return 0;
if (lenbytes == 0)
return 1;
pkt->subs->pwritten = lenbytes;
pkt->subs->lenbytes = lenbytes;
if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars)) {
OPENSSL_free(pkt->subs);
pkt->subs = NULL;
return 0;
}
pkt->subs->packet_len = 0;
return 1;
}
int WPACKET_init_static_len(WPACKET *pkt, unsigned char *buf, size_t len,
size_t lenbytes)
{
size_t max = maxmaxsize(lenbytes);
/* Internal API, so should not fail */
if (!ossl_assert(buf != NULL && len > 0))
return 0;
pkt->staticbuf = buf;
pkt->buf = NULL;
pkt->maxsize = (max < len) ? max : len;
pkt->endfirst = 0;
return wpacket_intern_init_len(pkt, lenbytes);
}
int WPACKET_init_der(WPACKET *pkt, unsigned char *buf, size_t len)
{
/* Internal API, so should not fail */
if (!ossl_assert(buf != NULL && len > 0))
return 0;
pkt->staticbuf = buf;
pkt->buf = NULL;
pkt->maxsize = len;
pkt->endfirst = 1;
return wpacket_intern_init_len(pkt, 0);
}
int WPACKET_init_len(WPACKET *pkt, BUF_MEM *buf, size_t lenbytes)
{
/* Internal API, so should not fail */
if (!ossl_assert(buf != NULL))
return 0;
pkt->staticbuf = NULL;
pkt->buf = buf;
pkt->maxsize = maxmaxsize(lenbytes);
pkt->endfirst = 0;
return wpacket_intern_init_len(pkt, lenbytes);
}
int WPACKET_init(WPACKET *pkt, BUF_MEM *buf)
{
return WPACKET_init_len(pkt, buf, 0);
}
int WPACKET_init_null(WPACKET *pkt, size_t lenbytes)
{
pkt->staticbuf = NULL;
pkt->buf = NULL;
pkt->maxsize = maxmaxsize(lenbytes);
pkt->endfirst = 0;
return wpacket_intern_init_len(pkt, 0);
}
int WPACKET_init_null_der(WPACKET *pkt)
{
pkt->staticbuf = NULL;
pkt->buf = NULL;
pkt->maxsize = SIZE_MAX;
pkt->endfirst = 1;
return wpacket_intern_init_len(pkt, 0);
}
int WPACKET_set_flags(WPACKET *pkt, unsigned int flags)
{
/* Internal API, so should not fail */
if (!ossl_assert(pkt->subs != NULL))
return 0;
pkt->subs->flags = flags;
return 1;
}
/* Store the |value| of length |len| at location |data| */
static int put_value(unsigned char *data, uint64_t value, size_t len)
{
if (data == NULL)
return 1;
for (data += len - 1; len > 0; len--) {
*data = (unsigned char)(value & 0xff);
data--;
value >>= 8;
}
/* Check whether we could fit the value in the assigned number of bytes */
if (value > 0)
return 0;
return 1;
}
#if !defined OPENSSL_NO_QUIC && !defined FIPS_MODULE
static int put_quic_value(unsigned char *data, size_t value, size_t len)
{
if (data == NULL)
return 1;
/* Value too large for field. */
if (ossl_quic_vlint_encode_len(value) > len)
return 0;
ossl_quic_vlint_encode_n(data, value, len);
return 1;
}
#endif
/*
* Internal helper function used by WPACKET_close(), WPACKET_finish() and
* WPACKET_fill_lengths() to close a sub-packet and write out its length if
* necessary. If |doclose| is 0 then it goes through the motions of closing
* (i.e. it fills in all the lengths), but doesn't actually close anything.
*/
static int wpacket_intern_close(WPACKET *pkt, WPACKET_SUB *sub, int doclose)
{
size_t packlen = pkt->written - sub->pwritten;
if (packlen == 0
&& (sub->flags & WPACKET_FLAGS_NON_ZERO_LENGTH) != 0)
return 0;
if (packlen == 0
&& sub->flags & WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) {
/* We can't handle this case. Return an error */
if (!doclose)
return 0;
/* Deallocate any bytes allocated for the length of the WPACKET */
if ((pkt->curr - sub->lenbytes) == sub->packet_len) {
pkt->written -= sub->lenbytes;
pkt->curr -= sub->lenbytes;
}
/* Don't write out the packet length */
sub->packet_len = 0;
sub->lenbytes = 0;
}
/* Write out the WPACKET length if needed */
if (sub->lenbytes > 0) {
unsigned char *buf = GETBUF(pkt);
if (buf != NULL) {
#if !defined OPENSSL_NO_QUIC && !defined FIPS_MODULE
if ((sub->flags & WPACKET_FLAGS_QUIC_VLINT) == 0) {
if (!put_value(&buf[sub->packet_len], packlen, sub->lenbytes))
return 0;
} else {
if (!put_quic_value(&buf[sub->packet_len], packlen, sub->lenbytes))
return 0;
}
#else
if (!put_value(&buf[sub->packet_len], packlen, sub->lenbytes))
return 0;
#endif
}
} else if (pkt->endfirst && sub->parent != NULL
&& (packlen != 0
|| (sub->flags
& WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH) == 0)) {
size_t tmplen = packlen;
size_t numlenbytes = 1;
while ((tmplen = tmplen >> 8) > 0)
numlenbytes++;
if (!WPACKET_put_bytes__(pkt, packlen, numlenbytes))
return 0;
if (packlen > 0x7f) {
numlenbytes |= 0x80;
if (!WPACKET_put_bytes_u8(pkt, numlenbytes))
return 0;
}
}
if (doclose) {
pkt->subs = sub->parent;
OPENSSL_free(sub);
}
return 1;
}
int WPACKET_fill_lengths(WPACKET *pkt)
{
WPACKET_SUB *sub;
if (!ossl_assert(pkt->subs != NULL))
return 0;
for (sub = pkt->subs; sub != NULL; sub = sub->parent) {
if (!wpacket_intern_close(pkt, sub, 0))
return 0;
}
return 1;
}
int WPACKET_close(WPACKET *pkt)
{
/*
* Internal API, so should not fail - but we do negative testing of this
* so no assert (otherwise the tests fail)
*/
if (pkt->subs == NULL || pkt->subs->parent == NULL)
return 0;
return wpacket_intern_close(pkt, pkt->subs, 1);
}
int WPACKET_finish(WPACKET *pkt)
{
int ret;
/*
* Internal API, so should not fail - but we do negative testing of this
* so no assert (otherwise the tests fail)
*/
if (pkt->subs == NULL || pkt->subs->parent != NULL)
return 0;
ret = wpacket_intern_close(pkt, pkt->subs, 1);
if (ret) {
OPENSSL_free(pkt->subs);
pkt->subs = NULL;
}
return ret;
}
int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)
{
WPACKET_SUB *sub;
unsigned char *lenchars;
/* Internal API, so should not fail */
if (!ossl_assert(pkt->subs != NULL))
return 0;
/* We don't support lenbytes greater than 0 when doing endfirst writing */
if (lenbytes > 0 && pkt->endfirst)
return 0;
if ((sub = OPENSSL_zalloc(sizeof(*sub))) == NULL)
return 0;
sub->parent = pkt->subs;
pkt->subs = sub;
sub->pwritten = pkt->written + lenbytes;
sub->lenbytes = lenbytes;
if (lenbytes == 0) {
sub->packet_len = 0;
return 1;
}
sub->packet_len = pkt->written;
if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))
return 0;
return 1;
}
int WPACKET_start_sub_packet(WPACKET *pkt)
{
return WPACKET_start_sub_packet_len__(pkt, 0);
}
int WPACKET_put_bytes__(WPACKET *pkt, uint64_t val, size_t size)
{
unsigned char *data;
/* Internal API, so should not fail */
if (!ossl_assert(size <= sizeof(uint64_t))
|| !WPACKET_allocate_bytes(pkt, size, &data)
|| !put_value(data, val, size))
return 0;
return 1;
}
int WPACKET_set_max_size(WPACKET *pkt, size_t maxsize)
{
WPACKET_SUB *sub;
size_t lenbytes;
/* Internal API, so should not fail */
if (!ossl_assert(pkt->subs != NULL))
return 0;
/* Find the WPACKET_SUB for the top level */
for (sub = pkt->subs; sub->parent != NULL; sub = sub->parent)
continue;
lenbytes = sub->lenbytes;
if (lenbytes == 0)
lenbytes = sizeof(pkt->maxsize);
if (maxmaxsize(lenbytes) < maxsize || maxsize < pkt->written)
return 0;
pkt->maxsize = maxsize;
return 1;
}
int WPACKET_memset(WPACKET *pkt, int ch, size_t len)
{
unsigned char *dest;
if (len == 0)
return 1;
if (!WPACKET_allocate_bytes(pkt, len, &dest))
return 0;
if (dest != NULL)
memset(dest, ch, len);
return 1;
}
int WPACKET_memcpy(WPACKET *pkt, const void *src, size_t len)
{
unsigned char *dest;
if (len == 0)
return 1;
if (!WPACKET_allocate_bytes(pkt, len, &dest))
return 0;
if (dest != NULL)
memcpy(dest, src, len);
return 1;
}
int WPACKET_sub_memcpy__(WPACKET *pkt, const void *src, size_t len,
size_t lenbytes)
{
if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)
|| !WPACKET_memcpy(pkt, src, len)
|| !WPACKET_close(pkt))
return 0;
return 1;
}
int WPACKET_get_total_written(WPACKET *pkt, size_t *written)
{
/* Internal API, so should not fail */
if (!ossl_assert(written != NULL))
return 0;
*written = pkt->written;
return 1;
}
int WPACKET_get_length(WPACKET *pkt, size_t *len)
{
/* Internal API, so should not fail */
if (!ossl_assert(pkt->subs != NULL && len != NULL))
return 0;
*len = pkt->written - pkt->subs->pwritten;
return 1;
}
unsigned char *WPACKET_get_curr(WPACKET *pkt)
{
unsigned char *buf = GETBUF(pkt);
if (buf == NULL)
return NULL;
if (pkt->endfirst)
return buf + pkt->maxsize - pkt->curr;
return buf + pkt->curr;
}
int WPACKET_is_null_buf(WPACKET *pkt)
{
return pkt->buf == NULL && pkt->staticbuf == NULL;
}
void WPACKET_cleanup(WPACKET *pkt)
{
WPACKET_SUB *sub, *parent;
for (sub = pkt->subs; sub != NULL; sub = parent) {
parent = sub->parent;
OPENSSL_free(sub);
}
pkt->subs = NULL;
}
#if !defined OPENSSL_NO_QUIC && !defined FIPS_MODULE
int WPACKET_start_quic_sub_packet_bound(WPACKET *pkt, size_t max_len)
{
size_t enclen = ossl_quic_vlint_encode_len(max_len);
if (enclen == 0)
return 0;
if (WPACKET_start_sub_packet_len__(pkt, enclen) == 0)
return 0;
pkt->subs->flags |= WPACKET_FLAGS_QUIC_VLINT;
return 1;
}
int WPACKET_start_quic_sub_packet(WPACKET *pkt)
{
/*
* Assume no (sub)packet will exceed 4GiB, thus the 8-byte encoding need not
* be used.
*/
return WPACKET_start_quic_sub_packet_bound(pkt, OSSL_QUIC_VLINT_4B_MIN);
}
int WPACKET_quic_sub_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
{
if (!WPACKET_start_quic_sub_packet_bound(pkt, len)
|| !WPACKET_allocate_bytes(pkt, len, allocbytes)
|| !WPACKET_close(pkt))
return 0;
return 1;
}
/*
* Write a QUIC variable-length integer to the packet.
*/
int WPACKET_quic_write_vlint(WPACKET *pkt, uint64_t v)
{
unsigned char *b = NULL;
size_t enclen = ossl_quic_vlint_encode_len(v);
if (enclen == 0)
return 0;
if (WPACKET_allocate_bytes(pkt, enclen, &b) == 0)
return 0;
ossl_quic_vlint_encode(b, v);
return 1;
}
#endif