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openssh/sshbuf-getput-basic.c
djm@openbsd.org 9d8c80f8a3 upstream: revert previous; it was broken (spotted by Theo)
OpenBSD-Commit-ID: 457c79afaca2f89ec2606405c1059b98b30d8b0d
2022-05-25 16:06:03 +10:00

634 lines
12 KiB
C

/* $OpenBSD: sshbuf-getput-basic.c,v 1.13 2022/05/25 06:03:44 djm Exp $ */
/*
* Copyright (c) 2011 Damien Miller
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#define SSHBUF_INTERNAL
#include "includes.h"
#include <sys/types.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include "ssherr.h"
#include "sshbuf.h"
int
sshbuf_get(struct sshbuf *buf, void *v, size_t len)
{
const u_char *p = sshbuf_ptr(buf);
int r;
if ((r = sshbuf_consume(buf, len)) < 0)
return r;
if (v != NULL && len != 0)
memcpy(v, p, len);
return 0;
}
int
sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp)
{
const u_char *p = sshbuf_ptr(buf);
int r;
if ((r = sshbuf_consume(buf, 8)) < 0)
return r;
if (valp != NULL)
*valp = PEEK_U64(p);
return 0;
}
int
sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp)
{
const u_char *p = sshbuf_ptr(buf);
int r;
if ((r = sshbuf_consume(buf, 4)) < 0)
return r;
if (valp != NULL)
*valp = PEEK_U32(p);
return 0;
}
int
sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp)
{
const u_char *p = sshbuf_ptr(buf);
int r;
if ((r = sshbuf_consume(buf, 2)) < 0)
return r;
if (valp != NULL)
*valp = PEEK_U16(p);
return 0;
}
int
sshbuf_get_u8(struct sshbuf *buf, u_char *valp)
{
const u_char *p = sshbuf_ptr(buf);
int r;
if ((r = sshbuf_consume(buf, 1)) < 0)
return r;
if (valp != NULL)
*valp = (u_int8_t)*p;
return 0;
}
static int
check_offset(const struct sshbuf *buf, int wr, size_t offset, size_t len)
{
if (sshbuf_ptr(buf) == NULL) /* calls sshbuf_check_sanity() */
return SSH_ERR_INTERNAL_ERROR;
if (offset >= SIZE_MAX - len)
return SSH_ERR_INVALID_ARGUMENT;
if (offset + len > sshbuf_len(buf)) {
return wr ?
SSH_ERR_NO_BUFFER_SPACE : SSH_ERR_MESSAGE_INCOMPLETE;
}
return 0;
}
static int
check_roffset(const struct sshbuf *buf, size_t offset, size_t len,
const u_char **p)
{
int r;
*p = NULL;
if ((r = check_offset(buf, 0, offset, len)) != 0)
return r;
*p = sshbuf_ptr(buf) + offset;
return 0;
}
int
sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp)
{
const u_char *p = NULL;
int r;
if (valp != NULL)
*valp = 0;
if ((r = check_roffset(buf, offset, 8, &p)) != 0)
return r;
if (valp != NULL)
*valp = PEEK_U64(p);
return 0;
}
int
sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp)
{
const u_char *p = NULL;
int r;
if (valp != NULL)
*valp = 0;
if ((r = check_roffset(buf, offset, 4, &p)) != 0)
return r;
if (valp != NULL)
*valp = PEEK_U32(p);
return 0;
}
int
sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp)
{
const u_char *p = NULL;
int r;
if (valp != NULL)
*valp = 0;
if ((r = check_roffset(buf, offset, 2, &p)) != 0)
return r;
if (valp != NULL)
*valp = PEEK_U16(p);
return 0;
}
int
sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp)
{
const u_char *p = NULL;
int r;
if (valp != NULL)
*valp = 0;
if ((r = check_roffset(buf, offset, 1, &p)) != 0)
return r;
if (valp != NULL)
*valp = *p;
return 0;
}
int
sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)
{
const u_char *val;
size_t len;
int r;
if (valp != NULL)
*valp = NULL;
if (lenp != NULL)
*lenp = 0;
if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0)
return r;
if (valp != NULL) {
if ((*valp = malloc(len + 1)) == NULL) {
SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
return SSH_ERR_ALLOC_FAIL;
}
if (len != 0)
memcpy(*valp, val, len);
(*valp)[len] = '\0';
}
if (lenp != NULL)
*lenp = len;
return 0;
}
int
sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)
{
size_t len;
const u_char *p;
int r;
if (valp != NULL)
*valp = NULL;
if (lenp != NULL)
*lenp = 0;
if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0)
return r;
if (valp != NULL)
*valp = p;
if (lenp != NULL)
*lenp = len;
if (sshbuf_consume(buf, len + 4) != 0) {
/* Shouldn't happen */
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
int
sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
size_t *lenp)
{
u_int32_t len;
const u_char *p = sshbuf_ptr(buf);
if (valp != NULL)
*valp = NULL;
if (lenp != NULL)
*lenp = 0;
if (sshbuf_len(buf) < 4) {
SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
return SSH_ERR_MESSAGE_INCOMPLETE;
}
len = PEEK_U32(p);
if (len > SSHBUF_SIZE_MAX - 4) {
SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));
return SSH_ERR_STRING_TOO_LARGE;
}
if (sshbuf_len(buf) - 4 < len) {
SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
return SSH_ERR_MESSAGE_INCOMPLETE;
}
if (valp != NULL)
*valp = p + 4;
if (lenp != NULL)
*lenp = len;
return 0;
}
int
sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)
{
size_t len;
const u_char *p, *z;
int r;
if (valp != NULL)
*valp = NULL;
if (lenp != NULL)
*lenp = 0;
if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
return r;
/* Allow a \0 only at the end of the string */
if (len > 0 &&
(z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {
SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));
return SSH_ERR_INVALID_FORMAT;
}
if ((r = sshbuf_skip_string(buf)) != 0)
return -1;
if (valp != NULL) {
if ((*valp = malloc(len + 1)) == NULL) {
SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
return SSH_ERR_ALLOC_FAIL;
}
if (len != 0)
memcpy(*valp, p, len);
(*valp)[len] = '\0';
}
if (lenp != NULL)
*lenp = (size_t)len;
return 0;
}
int
sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v)
{
u_int32_t len;
u_char *p;
int r;
/*
* Use sshbuf_peek_string_direct() to figure out if there is
* a complete string in 'buf' and copy the string directly
* into 'v'.
*/
if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 ||
(r = sshbuf_get_u32(buf, &len)) != 0 ||
(r = sshbuf_reserve(v, len, &p)) != 0 ||
(r = sshbuf_get(buf, p, len)) != 0)
return r;
return 0;
}
int
sshbuf_put(struct sshbuf *buf, const void *v, size_t len)
{
u_char *p;
int r;
if ((r = sshbuf_reserve(buf, len, &p)) < 0)
return r;
if (len != 0)
memcpy(p, v, len);
return 0;
}
int
sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v)
{
if (v == NULL)
return 0;
return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));
}
int
sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
{
va_list ap;
int r;
va_start(ap, fmt);
r = sshbuf_putfv(buf, fmt, ap);
va_end(ap);
return r;
}
int
sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
{
va_list ap2;
int r, len;
u_char *p;
VA_COPY(ap2, ap);
if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (len == 0) {
r = 0;
goto out; /* Nothing to do */
}
va_end(ap2);
VA_COPY(ap2, ap);
if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)
goto out;
if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {
r = SSH_ERR_INTERNAL_ERROR;
goto out; /* Shouldn't happen */
}
/* Consume terminating \0 */
if ((r = sshbuf_consume_end(buf, 1)) != 0)
goto out;
r = 0;
out:
va_end(ap2);
return r;
}
int
sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)
{
u_char *p;
int r;
if ((r = sshbuf_reserve(buf, 8, &p)) < 0)
return r;
POKE_U64(p, val);
return 0;
}
int
sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)
{
u_char *p;
int r;
if ((r = sshbuf_reserve(buf, 4, &p)) < 0)
return r;
POKE_U32(p, val);
return 0;
}
int
sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)
{
u_char *p;
int r;
if ((r = sshbuf_reserve(buf, 2, &p)) < 0)
return r;
POKE_U16(p, val);
return 0;
}
int
sshbuf_put_u8(struct sshbuf *buf, u_char val)
{
u_char *p;
int r;
if ((r = sshbuf_reserve(buf, 1, &p)) < 0)
return r;
p[0] = val;
return 0;
}
static int
check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p)
{
int r;
*p = NULL;
if ((r = check_offset(buf, 1, offset, len)) != 0)
return r;
if (sshbuf_mutable_ptr(buf) == NULL)
return SSH_ERR_BUFFER_READ_ONLY;
*p = sshbuf_mutable_ptr(buf) + offset;
return 0;
}
int
sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val)
{
u_char *p = NULL;
int r;
if ((r = check_woffset(buf, offset, 8, &p)) != 0)
return r;
POKE_U64(p, val);
return 0;
}
int
sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val)
{
u_char *p = NULL;
int r;
if ((r = check_woffset(buf, offset, 4, &p)) != 0)
return r;
POKE_U32(p, val);
return 0;
}
int
sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val)
{
u_char *p = NULL;
int r;
if ((r = check_woffset(buf, offset, 2, &p)) != 0)
return r;
POKE_U16(p, val);
return 0;
}
int
sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val)
{
u_char *p = NULL;
int r;
if ((r = check_woffset(buf, offset, 1, &p)) != 0)
return r;
*p = val;
return 0;
}
int
sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len)
{
u_char *p = NULL;
int r;
if ((r = check_woffset(buf, offset, len, &p)) != 0)
return r;
memcpy(p, v, len);
return 0;
}
int
sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
{
u_char *d;
int r;
if (len > SSHBUF_SIZE_MAX - 4) {
SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
return SSH_ERR_NO_BUFFER_SPACE;
}
if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
return r;
POKE_U32(d, len);
if (len != 0)
memcpy(d + 4, v, len);
return 0;
}
int
sshbuf_put_cstring(struct sshbuf *buf, const char *v)
{
return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v));
}
int
sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)
{
if (v == NULL)
return sshbuf_put_string(buf, NULL, 0);
return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));
}
int
sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)
{
const u_char *p;
size_t len;
struct sshbuf *ret;
int r;
if (buf == NULL || bufp == NULL)
return SSH_ERR_INVALID_ARGUMENT;
*bufp = NULL;
if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
return r;
if ((ret = sshbuf_from(p, len)) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */
(r = sshbuf_set_parent(ret, buf)) != 0) {
sshbuf_free(ret);
return r;
}
*bufp = ret;
return 0;
}
int
sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
{
u_char *d;
const u_char *s = (const u_char *)v;
int r, prepend;
if (len > SSHBUF_SIZE_MAX - 5) {
SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
return SSH_ERR_NO_BUFFER_SPACE;
}
/* Skip leading zero bytes */
for (; len > 0 && *s == 0; len--, s++)
;
/*
* If most significant bit is set then prepend a zero byte to
* avoid interpretation as a negative number.
*/
prepend = len > 0 && (s[0] & 0x80) != 0;
if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)
return r;
POKE_U32(d, len + prepend);
if (prepend)
d[4] = 0;
if (len != 0)
memcpy(d + 4 + prepend, s, len);
return 0;
}
int
sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
const u_char **valp, size_t *lenp)
{
const u_char *d;
size_t len, olen;
int r;
if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
return r;
len = olen;
/* Refuse negative (MSB set) bignums */
if ((len != 0 && (*d & 0x80) != 0))
return SSH_ERR_BIGNUM_IS_NEGATIVE;
/* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
if (len > SSHBUF_MAX_BIGNUM + 1 ||
(len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
return SSH_ERR_BIGNUM_TOO_LARGE;
/* Trim leading zeros */
while (len > 0 && *d == 0x00) {
d++;
len--;
}
if (valp != NULL)
*valp = d;
if (lenp != NULL)
*lenp = len;
if (sshbuf_consume(buf, olen + 4) != 0) {
/* Shouldn't happen */
SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
SSHBUF_ABORT();
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}