tor/src/feature/nodelist/describe.c
teor ec6fbf1ca6 nodelist: Use safe string functions in describe.c
Rewrite format_node_description() and router_get_verbose_nickname() to
use strlcpy() and strlcat(). The previous implementation used memcpy()
and pointer arithmetic, which was error-prone.

Closes ticket 31545. This is CID 1452819.
2019-08-29 13:09:08 +10:00

264 lines
8.1 KiB
C

/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file describe.c
* \brief Format short descriptions of relays.
*/
#define DESCRIBE_PRIVATE
#include "core/or/or.h"
#include "feature/nodelist/describe.h"
#include "core/or/extend_info_st.h"
#include "feature/nodelist/node_st.h"
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerstatus_st.h"
#include "feature/nodelist/microdesc_st.h"
/** Use <b>buf</b> (which must be at least NODE_DESC_BUF_LEN bytes long) to
* hold a human-readable description of a node with identity digest
* <b>id_digest</b>, nickname <b>nickname</b>, and addresses <b>addr32h</b> and
* <b>addr</b>.
*
* The <b>nickname</b> and <b>addr</b> fields are optional and may be set to
* NULL or the null address. The <b>addr32h</b> field is optional and may be
* set to 0.
*
* Return a pointer to the front of <b>buf</b>.
* If buf is NULL, return a string constant describing the error.
*/
STATIC const char *
format_node_description(char *buf,
const char *id_digest,
const char *nickname,
const tor_addr_t *addr,
uint32_t addr32h)
{
size_t rv = 0;
bool has_addr = addr && !tor_addr_is_null(addr);
if (!buf)
return "<NULL BUFFER>";
memset(buf, 0, NODE_DESC_BUF_LEN);
if (!id_digest) {
/* strlcpy() returns the length of the source string it attempted to copy,
* ignoring any required truncation due to the buffer length. */
rv = strlcpy(buf, "<NULL ID DIGEST>", NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
return buf;
}
/* strlcat() returns the length of the concatenated string it attempted to
* create, ignoring any required truncation due to the buffer length. */
rv = strlcat(buf, "$", NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
{
char hex_digest[HEX_DIGEST_LEN+1];
memset(hex_digest, 0, sizeof(hex_digest));
base16_encode(hex_digest, sizeof(hex_digest),
id_digest, DIGEST_LEN);
rv = strlcat(buf, hex_digest, NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
if (nickname) {
rv = strlcat(buf, "~", NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
rv = strlcat(buf, nickname, NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
if (addr32h || has_addr) {
rv = strlcat(buf, " at ", NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
if (addr32h) {
int ntoa_rv = 0;
char ipv4_addr_str[INET_NTOA_BUF_LEN];
memset(ipv4_addr_str, 0, sizeof(ipv4_addr_str));
struct in_addr in;
memset(&in, 0, sizeof(in));
in.s_addr = htonl(addr32h);
ntoa_rv = tor_inet_ntoa(&in, ipv4_addr_str, sizeof(ipv4_addr_str));
tor_assert_nonfatal(ntoa_rv >= 0);
rv = strlcat(buf, ipv4_addr_str, NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
/* Both addresses are valid */
if (addr32h && has_addr) {
rv = strlcat(buf, " and ", NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
if (has_addr) {
const char *str_rv = NULL;
char addr_str[TOR_ADDR_BUF_LEN];
memset(addr_str, 0, sizeof(addr_str));
str_rv = tor_addr_to_str(addr_str, addr, sizeof(addr_str), 1);
tor_assert_nonfatal(str_rv == addr_str);
rv = strlcat(buf, addr_str, NODE_DESC_BUF_LEN);
tor_assert_nonfatal(rv < NODE_DESC_BUF_LEN);
}
return buf;
}
/** Return a human-readable description of the routerinfo_t <b>ri</b>.
*
* This function is not thread-safe. Each call to this function invalidates
* previous values returned by this function.
*/
const char *
router_describe(const routerinfo_t *ri)
{
static char buf[NODE_DESC_BUF_LEN];
if (!ri)
return "<null>";
return format_node_description(buf,
ri->cache_info.identity_digest,
ri->nickname,
&ri->ipv6_addr,
ri->addr);
}
/** Return a human-readable description of the node_t <b>node</b>.
*
* This function is not thread-safe. Each call to this function invalidates
* previous values returned by this function.
*/
const char *
node_describe(const node_t *node)
{
static char buf[NODE_DESC_BUF_LEN];
const char *nickname = NULL;
uint32_t addr32h = 0;
const tor_addr_t *ipv6_addr = NULL;
if (!node)
return "<null>";
if (node->rs) {
nickname = node->rs->nickname;
addr32h = node->rs->addr;
ipv6_addr = &node->rs->ipv6_addr;
/* Support consensus versions less than 28, when IPv6 addresses were in
* microdescs. This code can be removed when 0.2.9 is no longer supported,
* and the MIN_METHOD_FOR_NO_A_LINES_IN_MICRODESC macro is removed. */
if (node->md && tor_addr_is_null(ipv6_addr)) {
ipv6_addr = &node->md->ipv6_addr;
}
} else if (node->ri) {
nickname = node->ri->nickname;
addr32h = node->ri->addr;
ipv6_addr = &node->ri->ipv6_addr;
} else {
return "<null rs and ri>";
}
return format_node_description(buf,
node->identity,
nickname,
ipv6_addr,
addr32h);
}
/** Return a human-readable description of the routerstatus_t <b>rs</b>.
*
* This function is not thread-safe. Each call to this function invalidates
* previous values returned by this function.
*/
const char *
routerstatus_describe(const routerstatus_t *rs)
{
static char buf[NODE_DESC_BUF_LEN];
if (!rs)
return "<null>";
return format_node_description(buf,
rs->identity_digest,
rs->nickname,
&rs->ipv6_addr,
rs->addr);
}
/** Return a human-readable description of the extend_info_t <b>ei</b>.
*
* This function is not thread-safe. Each call to this function invalidates
* previous values returned by this function.
*/
const char *
extend_info_describe(const extend_info_t *ei)
{
static char buf[NODE_DESC_BUF_LEN];
if (!ei)
return "<null>";
return format_node_description(buf,
ei->identity_digest,
ei->nickname,
&ei->addr,
0);
}
/** Set <b>buf</b> (which must have MAX_VERBOSE_NICKNAME_LEN+1 bytes) to the
* verbose representation of the identity of <b>router</b>. The format is:
* A dollar sign.
* The upper-case hexadecimal encoding of the SHA1 hash of router's identity.
* A "=" if the router is named (no longer implemented); a "~" if it is not.
* The router's nickname.
**/
void
router_get_verbose_nickname(char *buf, const routerinfo_t *router)
{
size_t rv = 0;
if (!buf)
return;
memset(buf, 0, MAX_VERBOSE_NICKNAME_LEN+1);
if (!router) {
/* strlcpy() returns the length of the source string it attempted to copy,
* ignoring any required truncation due to the buffer length. */
rv = strlcpy(buf, "<null>", MAX_VERBOSE_NICKNAME_LEN+1);
tor_assert_nonfatal(rv < MAX_VERBOSE_NICKNAME_LEN+1);
return;
}
/* strlcat() returns the length of the concatenated string it attempted to
* create, ignoring any required truncation due to the buffer length. */
rv = strlcat(buf, "$", MAX_VERBOSE_NICKNAME_LEN+1);
tor_assert_nonfatal(rv < MAX_VERBOSE_NICKNAME_LEN+1);
{
char hex_digest[HEX_DIGEST_LEN+1];
memset(hex_digest, 0, sizeof(hex_digest));
base16_encode(hex_digest, sizeof(hex_digest),
router->cache_info.identity_digest, DIGEST_LEN);
rv = strlcat(buf, hex_digest, MAX_VERBOSE_NICKNAME_LEN+1);
tor_assert_nonfatal(rv < MAX_VERBOSE_NICKNAME_LEN+1);
}
rv = strlcat(buf, "~", MAX_VERBOSE_NICKNAME_LEN+1);
tor_assert_nonfatal(rv < MAX_VERBOSE_NICKNAME_LEN+1);
rv = strlcat(buf, router->nickname, MAX_VERBOSE_NICKNAME_LEN+1);
tor_assert_nonfatal(rv < MAX_VERBOSE_NICKNAME_LEN+1);
}