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7f145b54af
tor/src/or/buffers.c
Nick Mathewson 7f145b54af Merge remote-tracking branch 'public/Fix_19450'
2016-08-12 16:11:28 -04:00

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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2016, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file buffers.c
* \brief Implements a generic interface buffer. Buffers are
* fairly opaque string holders that can read to or flush from:
* memory, file descriptors, or TLS connections. Buffers are implemented
* as linked lists of memory chunks.
**/
#define BUFFERS_PRIVATE
#include "or.h"
#include "addressmap.h"
#include "buffers.h"
#include "config.h"
#include "connection_edge.h"
#include "connection_or.h"
#include "control.h"
#include "reasons.h"
#include "ext_orport.h"
#include "util.h"
#include "torlog.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
//#define PARANOIA
#ifdef PARANOIA
/** Helper: If PARANOIA is defined, assert that the buffer in local variable
* <b>buf</b> is well-formed. */
#define check() STMT_BEGIN assert_buf_ok(buf); STMT_END
#else
#define check() STMT_NIL
#endif
/* Implementation notes:
*
* After flirting with memmove, and dallying with ring-buffers, we're finally
* getting up to speed with the 1970s and implementing buffers as a linked
* list of small chunks. Each buffer has such a list; data is removed from
* the head of the list, and added at the tail. The list is singly linked,
* and the buffer keeps a pointer to the head and the tail.
*
* Every chunk, except the tail, contains at least one byte of data. Data in
* each chunk is contiguous.
*
* When you need to treat the first N characters on a buffer as a contiguous
* string, use the buf_pullup function to make them so. Don't do this more
* than necessary.
*
* The major free Unix kernels have handled buffers like this since, like,
* forever.
*/
static void socks_request_set_socks5_error(socks_request_t *req,
socks5_reply_status_t reason);
static int parse_socks(const char *data, size_t datalen, socks_request_t *req,
int log_sockstype, int safe_socks, ssize_t *drain_out,
size_t *want_length_out);
static int parse_socks_client(const uint8_t *data, size_t datalen,
int state, char **reason,
ssize_t *drain_out);
/* Chunk manipulation functions */
#define CHUNK_HEADER_LEN STRUCT_OFFSET(chunk_t, mem[0])
/** Return the number of bytes needed to allocate a chunk to hold
* <b>memlen</b> bytes. */
#define CHUNK_ALLOC_SIZE(memlen) (CHUNK_HEADER_LEN + (memlen))
/** Return the number of usable bytes in a chunk allocated with
* malloc(<b>memlen</b>). */
#define CHUNK_SIZE_WITH_ALLOC(memlen) ((memlen) - CHUNK_HEADER_LEN)
/** Return the next character in <b>chunk</b> onto which data can be appended.
* If the chunk is full, this might be off the end of chunk->mem. */
static inline char *
CHUNK_WRITE_PTR(chunk_t *chunk)
{
return chunk->data + chunk->datalen;
}
/** Return the number of bytes that can be written onto <b>chunk</b> without
* running out of space. */
static inline size_t
CHUNK_REMAINING_CAPACITY(const chunk_t *chunk)
{
return (chunk->mem + chunk->memlen) - (chunk->data + chunk->datalen);
}
/** Move all bytes stored in <b>chunk</b> to the front of <b>chunk</b>->mem,
* to free up space at the end. */
static inline void
chunk_repack(chunk_t *chunk)
{
if (chunk->datalen && chunk->data != &chunk->mem[0]) {
memmove(chunk->mem, chunk->data, chunk->datalen);
}
chunk->data = &chunk->mem[0];
}
/** Keep track of total size of allocated chunks for consistency asserts */
static size_t total_bytes_allocated_in_chunks = 0;
static void
buf_chunk_free_unchecked(chunk_t *chunk)
{
if (!chunk)
return;
#ifdef DEBUG_CHUNK_ALLOC
tor_assert(CHUNK_ALLOC_SIZE(chunk->memlen) == chunk->DBG_alloc);
#endif
tor_assert(total_bytes_allocated_in_chunks >=
CHUNK_ALLOC_SIZE(chunk->memlen));
total_bytes_allocated_in_chunks -= CHUNK_ALLOC_SIZE(chunk->memlen);
tor_free(chunk);
}
static inline chunk_t *
chunk_new_with_alloc_size(size_t alloc)
{
chunk_t *ch;
ch = tor_malloc(alloc);
ch->next = NULL;
ch->datalen = 0;
#ifdef DEBUG_CHUNK_ALLOC
ch->DBG_alloc = alloc;
#endif
ch->memlen = CHUNK_SIZE_WITH_ALLOC(alloc);
total_bytes_allocated_in_chunks += alloc;
ch->data = &ch->mem[0];
return ch;
}
/** Expand <b>chunk</b> until it can hold <b>sz</b> bytes, and return a
* new pointer to <b>chunk</b>. Old pointers are no longer valid. */
static inline chunk_t *
chunk_grow(chunk_t *chunk, size_t sz)
{
off_t offset;
size_t memlen_orig = chunk->memlen;
tor_assert(sz > chunk->memlen);
offset = chunk->data - chunk->mem;
chunk = tor_realloc(chunk, CHUNK_ALLOC_SIZE(sz));
chunk->memlen = sz;
chunk->data = chunk->mem + offset;
#ifdef DEBUG_CHUNK_ALLOC
tor_assert(chunk->DBG_alloc == CHUNK_ALLOC_SIZE(memlen_orig));
chunk->DBG_alloc = CHUNK_ALLOC_SIZE(sz);
#endif
total_bytes_allocated_in_chunks +=
CHUNK_ALLOC_SIZE(sz) - CHUNK_ALLOC_SIZE(memlen_orig);
return chunk;
}
/** If a read onto the end of a chunk would be smaller than this number, then
* just start a new chunk. */
#define MIN_READ_LEN 8
/** Every chunk should take up at least this many bytes. */
#define MIN_CHUNK_ALLOC 256
/** No chunk should take up more than this many bytes. */
#define MAX_CHUNK_ALLOC 65536
/** Return the allocation size we'd like to use to hold <b>target</b>
* bytes. */
static inline size_t
preferred_chunk_size(size_t target)
{
size_t sz = MIN_CHUNK_ALLOC;
while (CHUNK_SIZE_WITH_ALLOC(sz) < target) {
sz <<= 1;
}
return sz;
}
/** Collapse data from the first N chunks from <b>buf</b> into buf->head,
* growing it as necessary, until buf->head has the first <b>bytes</b> bytes
* of data from the buffer, or until buf->head has all the data in <b>buf</b>.
*/
STATIC void
buf_pullup(buf_t *buf, size_t bytes)
{
chunk_t *dest, *src;
size_t capacity;
if (!buf->head)
return;
check();
if (buf->datalen < bytes)
bytes = buf->datalen;
capacity = bytes;
if (buf->head->datalen >= bytes)
return;
if (buf->head->memlen >= capacity) {
/* We don't need to grow the first chunk, but we might need to repack it.*/
size_t needed = capacity - buf->head->datalen;
if (CHUNK_REMAINING_CAPACITY(buf->head) < needed)
chunk_repack(buf->head);
tor_assert(CHUNK_REMAINING_CAPACITY(buf->head) >= needed);
} else {
chunk_t *newhead;
size_t newsize;
/* We need to grow the chunk. */
chunk_repack(buf->head);
newsize = CHUNK_SIZE_WITH_ALLOC(preferred_chunk_size(capacity));
newhead = chunk_grow(buf->head, newsize);
tor_assert(newhead->memlen >= capacity);
if (newhead != buf->head) {
if (buf->tail == buf->head)
buf->tail = newhead;
buf->head = newhead;
}
}
dest = buf->head;
while (dest->datalen < bytes) {
size_t n = bytes - dest->datalen;
src = dest->next;
tor_assert(src);
if (n >= src->datalen) {
memcpy(CHUNK_WRITE_PTR(dest), src->data, src->datalen);
dest->datalen += src->datalen;
dest->next = src->next;
if (buf->tail == src)
buf->tail = dest;
buf_chunk_free_unchecked(src);
} else {
memcpy(CHUNK_WRITE_PTR(dest), src->data, n);
dest->datalen += n;
src->data += n;
src->datalen -= n;
tor_assert(dest->datalen == bytes);
}
}
check();
}
#ifdef TOR_UNIT_TESTS
void
buf_get_first_chunk_data(const buf_t *buf, const char **cp, size_t *sz)
{
if (!buf || !buf->head) {
*cp = NULL;
*sz = 0;
} else {
*cp = buf->head->data;
*sz = buf->head->datalen;
}
}
#endif
/** Remove the first <b>n</b> bytes from buf. */
static inline void
buf_remove_from_front(buf_t *buf, size_t n)
{
tor_assert(buf->datalen >= n);
while (n) {
tor_assert(buf->head);
if (buf->head->datalen > n) {
buf->head->datalen -= n;
buf->head->data += n;
buf->datalen -= n;
return;
} else {
chunk_t *victim = buf->head;
n -= victim->datalen;
buf->datalen -= victim->datalen;
buf->head = victim->next;
if (buf->tail == victim)
buf->tail = NULL;
buf_chunk_free_unchecked(victim);
}
}
check();
}
/** Create and return a new buf with default chunk capacity <b>size</b>.
*/
buf_t *
buf_new_with_capacity(size_t size)
{
buf_t *b = buf_new();
b->default_chunk_size = preferred_chunk_size(size);
return b;
}
/** Allocate and return a new buffer with default capacity. */
buf_t *
buf_new(void)
{
buf_t *buf = tor_malloc_zero(sizeof(buf_t));
buf->magic = BUFFER_MAGIC;
buf->default_chunk_size = 4096;
return buf;
}
size_t
buf_get_default_chunk_size(const buf_t *buf)
{
return buf->default_chunk_size;
}
/** Remove all data from <b>buf</b>. */
void
buf_clear(buf_t *buf)
{
chunk_t *chunk, *next;
buf->datalen = 0;
for (chunk = buf->head; chunk; chunk = next) {
next = chunk->next;
buf_chunk_free_unchecked(chunk);
}
buf->head = buf->tail = NULL;
}
/** Return the number of bytes stored in <b>buf</b> */
MOCK_IMPL(size_t,
buf_datalen, (const buf_t *buf))
{
return buf->datalen;
}
/** Return the total length of all chunks used in <b>buf</b>. */
size_t
buf_allocation(const buf_t *buf)
{
size_t total = 0;
const chunk_t *chunk;
for (chunk = buf->head; chunk; chunk = chunk->next) {
total += CHUNK_ALLOC_SIZE(chunk->memlen);
}
return total;
}
/** Return the number of bytes that can be added to <b>buf</b> without
* performing any additional allocation. */
size_t
buf_slack(const buf_t *buf)
{
if (!buf->tail)
return 0;
else
return CHUNK_REMAINING_CAPACITY(buf->tail);
}
/** Release storage held by <b>buf</b>. */
void
buf_free(buf_t *buf)
{
if (!buf)
return;
buf_clear(buf);
buf->magic = 0xdeadbeef;
tor_free(buf);
}
/** Return a new copy of <b>in_chunk</b> */
static chunk_t *
chunk_copy(const chunk_t *in_chunk)
{
chunk_t *newch = tor_memdup(in_chunk, CHUNK_ALLOC_SIZE(in_chunk->memlen));
total_bytes_allocated_in_chunks += CHUNK_ALLOC_SIZE(in_chunk->memlen);
#ifdef DEBUG_CHUNK_ALLOC
newch->DBG_alloc = CHUNK_ALLOC_SIZE(in_chunk->memlen);
#endif
newch->next = NULL;
if (in_chunk->data) {
off_t offset = in_chunk->data - in_chunk->mem;
newch->data = newch->mem + offset;
}
return newch;
}
/** Return a new copy of <b>buf</b> */
buf_t *
buf_copy(const buf_t *buf)
{
chunk_t *ch;
buf_t *out = buf_new();
out->default_chunk_size = buf->default_chunk_size;
for (ch = buf->head; ch; ch = ch->next) {
chunk_t *newch = chunk_copy(ch);
if (out->tail) {
out->tail->next = newch;
out->tail = newch;
} else {
out->head = out->tail = newch;
}
}
out->datalen = buf->datalen;
return out;
}
/** Append a new chunk with enough capacity to hold <b>capacity</b> bytes to
* the tail of <b>buf</b>. If <b>capped</b>, don't allocate a chunk bigger
* than MAX_CHUNK_ALLOC. */
static chunk_t *
buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped)
{
chunk_t *chunk;
if (CHUNK_ALLOC_SIZE(capacity) < buf->default_chunk_size) {
chunk = chunk_new_with_alloc_size(buf->default_chunk_size);
} else if (capped && CHUNK_ALLOC_SIZE(capacity) > MAX_CHUNK_ALLOC) {
chunk = chunk_new_with_alloc_size(MAX_CHUNK_ALLOC);
} else {
chunk = chunk_new_with_alloc_size(preferred_chunk_size(capacity));
}
chunk->inserted_time = (uint32_t)monotime_coarse_absolute_msec();
if (buf->tail) {
tor_assert(buf->head);
buf->tail->next = chunk;
buf->tail = chunk;
} else {
tor_assert(!buf->head);
buf->head = buf->tail = chunk;
}
check();
return chunk;
}
/** Return the age of the oldest chunk in the buffer <b>buf</b>, in
* milliseconds. Requires the current monotonic time, in truncated msec,
* as its input <b>now</b>.
*/
uint32_t
buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now)
{
if (buf->head) {
return now - buf->head->inserted_time;
} else {
return 0;
}
}
size_t
buf_get_total_allocation(void)
{
return total_bytes_allocated_in_chunks;
}
/** Read up to <b>at_most</b> bytes from the socket <b>fd</b> into
* <b>chunk</b> (which must be on <b>buf</b>). If we get an EOF, set
* *<b>reached_eof</b> to 1. Return -1 on error, 0 on eof or blocking,
* and the number of bytes read otherwise. */
static inline int
read_to_chunk(buf_t *buf, chunk_t *chunk, tor_socket_t fd, size_t at_most,
int *reached_eof, int *socket_error)
{
ssize_t read_result;
if (at_most > CHUNK_REMAINING_CAPACITY(chunk))
at_most = CHUNK_REMAINING_CAPACITY(chunk);
read_result = tor_socket_recv(fd, CHUNK_WRITE_PTR(chunk), at_most, 0);
if (read_result < 0) {
int e = tor_socket_errno(fd);
if (!ERRNO_IS_EAGAIN(e)) { /* it's a real error */
#ifdef _WIN32
if (e == WSAENOBUFS)
log_warn(LD_NET,"recv() failed: WSAENOBUFS. Not enough ram?");
#endif
*socket_error = e;
return -1;
}
return 0; /* would block. */
} else if (read_result == 0) {
log_debug(LD_NET,"Encountered eof on fd %d", (int)fd);
*reached_eof = 1;
return 0;
} else { /* actually got bytes. */
buf->datalen += read_result;
chunk->datalen += read_result;
log_debug(LD_NET,"Read %ld bytes. %d on inbuf.", (long)read_result,
(int)buf->datalen);
tor_assert(read_result < INT_MAX);
return (int)read_result;
}
}
/** As read_to_chunk(), but return (negative) error code on error, blocking,
* or TLS, and the number of bytes read otherwise. */
static inline int
read_to_chunk_tls(buf_t *buf, chunk_t *chunk, tor_tls_t *tls,
size_t at_most)
{
int read_result;
tor_assert(CHUNK_REMAINING_CAPACITY(chunk) >= at_most);
read_result = tor_tls_read(tls, CHUNK_WRITE_PTR(chunk), at_most);
if (read_result < 0)
return read_result;
buf->datalen += read_result;
chunk->datalen += read_result;
return read_result;
}
/** Read from socket <b>s</b>, writing onto end of <b>buf</b>. Read at most
* <b>at_most</b> bytes, growing the buffer as necessary. If recv() returns 0
* (because of EOF), set *<b>reached_eof</b> to 1 and return 0. Return -1 on
* error; else return the number of bytes read.
*/
/* XXXX indicate "read blocked" somehow? */
int
read_to_buf(tor_socket_t s, size_t at_most, buf_t *buf, int *reached_eof,
int *socket_error)
{
/* XXXX It's stupid to overload the return values for these functions:
* "error status" and "number of bytes read" are not mutually exclusive.
*/
int r = 0;
size_t total_read = 0;
check();
tor_assert(reached_eof);
tor_assert(SOCKET_OK(s));
while (at_most > total_read) {
size_t readlen = at_most - total_read;
chunk_t *chunk;
if (!buf->tail || CHUNK_REMAINING_CAPACITY(buf->tail) < MIN_READ_LEN) {
chunk = buf_add_chunk_with_capacity(buf, at_most, 1);
if (readlen > chunk->memlen)
readlen = chunk->memlen;
} else {
size_t cap = CHUNK_REMAINING_CAPACITY(buf->tail);
chunk = buf->tail;
if (cap < readlen)
readlen = cap;
}
r = read_to_chunk(buf, chunk, s, readlen, reached_eof, socket_error);
check();
if (r < 0)
return r; /* Error */
tor_assert(total_read+r < INT_MAX);
total_read += r;
if ((size_t)r < readlen) { /* eof, block, or no more to read. */
break;
}
}
return (int)total_read;
}
/** As read_to_buf, but reads from a TLS connection, and returns a TLS
* status value rather than the number of bytes read.
*
* Using TLS on OR connections complicates matters in two ways.
*
* First, a TLS stream has its own read buffer independent of the
* connection's read buffer. (TLS needs to read an entire frame from
* the network before it can decrypt any data. Thus, trying to read 1
* byte from TLS can require that several KB be read from the network
* and decrypted. The extra data is stored in TLS's decrypt buffer.)
* Because the data hasn't been read by Tor (it's still inside the TLS),
* this means that sometimes a connection "has stuff to read" even when
* poll() didn't return POLLIN. The tor_tls_get_pending_bytes function is
* used in connection.c to detect TLS objects with non-empty internal
* buffers and read from them again.
*
* Second, the TLS stream's events do not correspond directly to network
* events: sometimes, before a TLS stream can read, the network must be
* ready to write -- or vice versa.
*/
int
read_to_buf_tls(tor_tls_t *tls, size_t at_most, buf_t *buf)
{
int r = 0;
size_t total_read = 0;
check_no_tls_errors();
check();
while (at_most > total_read) {
size_t readlen = at_most - total_read;
chunk_t *chunk;
if (!buf->tail || CHUNK_REMAINING_CAPACITY(buf->tail) < MIN_READ_LEN) {
chunk = buf_add_chunk_with_capacity(buf, at_most, 1);
if (readlen > chunk->memlen)
readlen = chunk->memlen;
} else {
size_t cap = CHUNK_REMAINING_CAPACITY(buf->tail);
chunk = buf->tail;
if (cap < readlen)
readlen = cap;
}
r = read_to_chunk_tls(buf, chunk, tls, readlen);
check();
if (r < 0)
return r; /* Error */
tor_assert(total_read+r < INT_MAX);
total_read += r;
if ((size_t)r < readlen) /* eof, block, or no more to read. */
break;
}
return (int)total_read;
}
/** Helper for flush_buf(): try to write <b>sz</b> bytes from chunk
* <b>chunk</b> of buffer <b>buf</b> onto socket <b>s</b>. On success, deduct
* the bytes written from *<b>buf_flushlen</b>. Return the number of bytes
* written on success, 0 on blocking, -1 on failure.
*/
static inline int
flush_chunk(tor_socket_t s, buf_t *buf, chunk_t *chunk, size_t sz,
size_t *buf_flushlen)
{
ssize_t write_result;
if (sz > chunk->datalen)
sz = chunk->datalen;
write_result = tor_socket_send(s, chunk->data, sz, 0);
if (write_result < 0) {
int e = tor_socket_errno(s);
if (!ERRNO_IS_EAGAIN(e)) { /* it's a real error */
#ifdef _WIN32
if (e == WSAENOBUFS)
log_warn(LD_NET,"write() failed: WSAENOBUFS. Not enough ram?");
#endif
return -1;
}
log_debug(LD_NET,"write() would block, returning.");
return 0;
} else {
*buf_flushlen -= write_result;
buf_remove_from_front(buf, write_result);
tor_assert(write_result < INT_MAX);
return (int)write_result;
}
}
/** Helper for flush_buf_tls(): try to write <b>sz</b> bytes from chunk
* <b>chunk</b> of buffer <b>buf</b> onto socket <b>s</b>. (Tries to write
* more if there is a forced pending write size.) On success, deduct the
* bytes written from *<b>buf_flushlen</b>. Return the number of bytes
* written on success, and a TOR_TLS error code on failure or blocking.
*/
static inline int
flush_chunk_tls(tor_tls_t *tls, buf_t *buf, chunk_t *chunk,
size_t sz, size_t *buf_flushlen)
{
int r;
size_t forced;
char *data;
forced = tor_tls_get_forced_write_size(tls);
if (forced > sz)
sz = forced;
if (chunk) {
data = chunk->data;
tor_assert(sz <= chunk->datalen);
} else {
data = NULL;
tor_assert(sz == 0);
}
r = tor_tls_write(tls, data, sz);
if (r < 0)
return r;
if (*buf_flushlen > (size_t)r)
*buf_flushlen -= r;
else
*buf_flushlen = 0;
buf_remove_from_front(buf, r);
log_debug(LD_NET,"flushed %d bytes, %d ready to flush, %d remain.",
r,(int)*buf_flushlen,(int)buf->datalen);
return r;
}
/** Write data from <b>buf</b> to the socket <b>s</b>. Write at most
* <b>sz</b> bytes, decrement *<b>buf_flushlen</b> by
* the number of bytes actually written, and remove the written bytes
* from the buffer. Return the number of bytes written on success,
* -1 on failure. Return 0 if write() would block.
*/
int
flush_buf(tor_socket_t s, buf_t *buf, size_t sz, size_t *buf_flushlen)
{
/* XXXX It's stupid to overload the return values for these functions:
* "error status" and "number of bytes flushed" are not mutually exclusive.
*/
int r;
size_t flushed = 0;
tor_assert(buf_flushlen);
tor_assert(SOCKET_OK(s));
tor_assert(*buf_flushlen <= buf->datalen);
tor_assert(sz <= *buf_flushlen);
check();
while (sz) {
size_t flushlen0;
tor_assert(buf->head);
if (buf->head->datalen >= sz)
flushlen0 = sz;
else
flushlen0 = buf->head->datalen;
r = flush_chunk(s, buf, buf->head, flushlen0, buf_flushlen);
check();
if (r < 0)
return r;
flushed += r;
sz -= r;
if (r == 0 || (size_t)r < flushlen0) /* can't flush any more now. */
break;
}
tor_assert(flushed < INT_MAX);
return (int)flushed;
}
/** As flush_buf(), but writes data to a TLS connection. Can write more than
* <b>flushlen</b> bytes.
*/
int
flush_buf_tls(tor_tls_t *tls, buf_t *buf, size_t flushlen,
size_t *buf_flushlen)
{
int r;
size_t flushed = 0;
ssize_t sz;
tor_assert(buf_flushlen);
tor_assert(*buf_flushlen <= buf->datalen);
tor_assert(flushlen <= *buf_flushlen);
sz = (ssize_t) flushlen;
/* we want to let tls write even if flushlen is zero, because it might
* have a partial record pending */
check_no_tls_errors();
check();
do {
size_t flushlen0;
if (buf->head) {
if ((ssize_t)buf->head->datalen >= sz)
flushlen0 = sz;
else
flushlen0 = buf->head->datalen;
} else {
flushlen0 = 0;
}
r = flush_chunk_tls(tls, buf, buf->head, flushlen0, buf_flushlen);
check();
if (r < 0)
return r;
flushed += r;
sz -= r;
if (r == 0) /* Can't flush any more now. */
break;
} while (sz > 0);
tor_assert(flushed < INT_MAX);
return (int)flushed;
}
/** Append <b>string_len</b> bytes from <b>string</b> to the end of
* <b>buf</b>.
*
* Return the new length of the buffer on success, -1 on failure.
*/
int
write_to_buf(const char *string, size_t string_len, buf_t *buf)
{
if (!string_len)
return (int)buf->datalen;
check();
while (string_len) {
size_t copy;
if (!buf->tail || !CHUNK_REMAINING_CAPACITY(buf->tail))
buf_add_chunk_with_capacity(buf, string_len, 1);
copy = CHUNK_REMAINING_CAPACITY(buf->tail);
if (copy > string_len)
copy = string_len;
memcpy(CHUNK_WRITE_PTR(buf->tail), string, copy);
string_len -= copy;
string += copy;
buf->datalen += copy;
buf->tail->datalen += copy;
}
check();
tor_assert(buf->datalen < INT_MAX);
return (int)buf->datalen;
}
/** Helper: copy the first <b>string_len</b> bytes from <b>buf</b>
* onto <b>string</b>.
*/
static inline void
peek_from_buf(char *string, size_t string_len, const buf_t *buf)
{
chunk_t *chunk;
tor_assert(string);
/* make sure we don't ask for too much */
tor_assert(string_len <= buf->datalen);
/* assert_buf_ok(buf); */
chunk = buf->head;
while (string_len) {
size_t copy = string_len;
tor_assert(chunk);
if (chunk->datalen < copy)
copy = chunk->datalen;
memcpy(string, chunk->data, copy);
string_len -= copy;
string += copy;
chunk = chunk->next;
}
}
/** Remove <b>string_len</b> bytes from the front of <b>buf</b>, and store
* them into <b>string</b>. Return the new buffer size. <b>string_len</b>
* must be \<= the number of bytes on the buffer.
*/
int
fetch_from_buf(char *string, size_t string_len, buf_t *buf)
{
/* There must be string_len bytes in buf; write them onto string,
* then memmove buf back (that is, remove them from buf).
*
* Return the number of bytes still on the buffer. */
check();
peek_from_buf(string, string_len, buf);
buf_remove_from_front(buf, string_len);
check();
tor_assert(buf->datalen < INT_MAX);
return (int)buf->datalen;
}
/** True iff the cell command <b>command</b> is one that implies a
* variable-length cell in Tor link protocol <b>linkproto</b>. */
static inline int
cell_command_is_var_length(uint8_t command, int linkproto)
{
/* If linkproto is v2 (2), CELL_VERSIONS is the only variable-length cells
* work as implemented here. If it's 1, there are no variable-length cells.
* Tor does not support other versions right now, and so can't negotiate
* them.
*/
switch (linkproto) {
case 1:
/* Link protocol version 1 has no variable-length cells. */
return 0;
case 2:
/* In link protocol version 2, VERSIONS is the only variable-length cell */
return command == CELL_VERSIONS;
case 0:
case 3:
default:
/* In link protocol version 3 and later, and in version "unknown",
* commands 128 and higher indicate variable-length. VERSIONS is
* grandfathered in. */
return command == CELL_VERSIONS || command >= 128;
}
}
/** Check <b>buf</b> for a variable-length cell according to the rules of link
* protocol version <b>linkproto</b>. If one is found, pull it off the buffer
* and assign a newly allocated var_cell_t to *<b>out</b>, and return 1.
* Return 0 if whatever is on the start of buf_t is not a variable-length
* cell. Return 1 and set *<b>out</b> to NULL if there seems to be the start
* of a variable-length cell on <b>buf</b>, but the whole thing isn't there
* yet. */
int
fetch_var_cell_from_buf(buf_t *buf, var_cell_t **out, int linkproto)
{
char hdr[VAR_CELL_MAX_HEADER_SIZE];
var_cell_t *result;
uint8_t command;
uint16_t length;
const int wide_circ_ids = linkproto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS;
const int circ_id_len = get_circ_id_size(wide_circ_ids);
const unsigned header_len = get_var_cell_header_size(wide_circ_ids);
check();
*out = NULL;
if (buf->datalen < header_len)
return 0;
peek_from_buf(hdr, header_len, buf);
command = get_uint8(hdr + circ_id_len);
if (!(cell_command_is_var_length(command, linkproto)))
return 0;
length = ntohs(get_uint16(hdr + circ_id_len + 1));
if (buf->datalen < (size_t)(header_len+length))
return 1;
result = var_cell_new(length);
result->command = command;
if (wide_circ_ids)
result->circ_id = ntohl(get_uint32(hdr));
else
result->circ_id = ntohs(get_uint16(hdr));
buf_remove_from_front(buf, header_len);
peek_from_buf((char*) result->payload, length, buf);
buf_remove_from_front(buf, length);
check();
*out = result;
return 1;
}
/** Move up to *<b>buf_flushlen</b> bytes from <b>buf_in</b> to
* <b>buf_out</b>, and modify *<b>buf_flushlen</b> appropriately.
* Return the number of bytes actually copied.
*/
int
move_buf_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen)
{
/* We can do way better here, but this doesn't turn up in any profiles. */
char b[4096];
size_t cp, len;
len = *buf_flushlen;
if (len > buf_in->datalen)
len = buf_in->datalen;
cp = len; /* Remember the number of bytes we intend to copy. */
tor_assert(cp < INT_MAX);
while (len) {
/* This isn't the most efficient implementation one could imagine, since
* it does two copies instead of 1, but I kinda doubt that this will be
* critical path. */
size_t n = len > sizeof(b) ? sizeof(b) : len;
fetch_from_buf(b, n, buf_in);
write_to_buf(b, n, buf_out);
len -= n;
}
*buf_flushlen -= cp;
return (int)cp;
}
/** Internal structure: represents a position in a buffer. */
typedef struct buf_pos_t {
const chunk_t *chunk; /**< Which chunk are we pointing to? */
int pos;/**< Which character inside the chunk's data are we pointing to? */
size_t chunk_pos; /**< Total length of all previous chunks. */
} buf_pos_t;
/** Initialize <b>out</b> to point to the first character of <b>buf</b>.*/
static void
buf_pos_init(const buf_t *buf, buf_pos_t *out)
{
out->chunk = buf->head;
out->pos = 0;
out->chunk_pos = 0;
}
/** Advance <b>out</b> to the first appearance of <b>ch</b> at the current
* position of <b>out</b>, or later. Return -1 if no instances are found;
* otherwise returns the absolute position of the character. */
static off_t
buf_find_pos_of_char(char ch, buf_pos_t *out)
{
const chunk_t *chunk;
int pos;
tor_assert(out);
if (out->chunk) {
if (out->chunk->datalen) {
tor_assert(out->pos < (off_t)out->chunk->datalen);
} else {
tor_assert(out->pos == 0);
}
}
pos = out->pos;
for (chunk = out->chunk; chunk; chunk = chunk->next) {
char *cp = memchr(chunk->data+pos, ch, chunk->datalen - pos);
if (cp) {
out->chunk = chunk;
tor_assert(cp - chunk->data < INT_MAX);
out->pos = (int)(cp - chunk->data);
return out->chunk_pos + out->pos;
} else {
out->chunk_pos += chunk->datalen;
pos = 0;
}
}
return -1;
}
/** Advance <b>pos</b> by a single character, if there are any more characters
* in the buffer. Returns 0 on success, -1 on failure. */
static inline int
buf_pos_inc(buf_pos_t *pos)
{
++pos->pos;
if (pos->pos == (off_t)pos->chunk->datalen) {
if (!pos->chunk->next)
return -1;
pos->chunk_pos += pos->chunk->datalen;
pos->chunk = pos->chunk->next;
pos->pos = 0;
}
return 0;
}
/** Return true iff the <b>n</b>-character string in <b>s</b> appears
* (verbatim) at <b>pos</b>. */
static int
buf_matches_at_pos(const buf_pos_t *pos, const char *s, size_t n)
{
buf_pos_t p;
if (!n)
return 1;
memcpy(&p, pos, sizeof(p));
while (1) {
char ch = p.chunk->data[p.pos];
if (ch != *s)
return 0;
++s;
/* If we're out of characters that don't match, we match. Check this
* _before_ we test incrementing pos, in case we're at the end of the
* string. */
if (--n == 0)
return 1;
if (buf_pos_inc(&p)<0)
return 0;
}
}
/** Return the first position in <b>buf</b> at which the <b>n</b>-character
* string <b>s</b> occurs, or -1 if it does not occur. */
STATIC int
buf_find_string_offset(const buf_t *buf, const char *s, size_t n)
{
buf_pos_t pos;
buf_pos_init(buf, &pos);
while (buf_find_pos_of_char(*s, &pos) >= 0) {
if (buf_matches_at_pos(&pos, s, n)) {
tor_assert(pos.chunk_pos + pos.pos < INT_MAX);
return (int)(pos.chunk_pos + pos.pos);
} else {
if (buf_pos_inc(&pos)<0)
return -1;
}
}
return -1;
}
/** There is a (possibly incomplete) http statement on <b>buf</b>, of the
* form "\%s\\r\\n\\r\\n\%s", headers, body. (body may contain NULs.)
* If a) the headers include a Content-Length field and all bytes in
* the body are present, or b) there's no Content-Length field and
* all headers are present, then:
*
* - strdup headers into <b>*headers_out</b>, and NUL-terminate it.
* - memdup body into <b>*body_out</b>, and NUL-terminate it.
* - Then remove them from <b>buf</b>, and return 1.
*
* - If headers or body is NULL, discard that part of the buf.
* - If a headers or body doesn't fit in the arg, return -1.
* (We ensure that the headers or body don't exceed max len,
* _even if_ we're planning to discard them.)
* - If force_complete is true, then succeed even if not all of the
* content has arrived.
*
* Else, change nothing and return 0.
*/
int
fetch_from_buf_http(buf_t *buf,
char **headers_out, size_t max_headerlen,
char **body_out, size_t *body_used, size_t max_bodylen,
int force_complete)
{
char *headers, *p;
size_t headerlen, bodylen, contentlen;
int crlf_offset;
check();
if (!buf->head)
return 0;
crlf_offset = buf_find_string_offset(buf, "\r\n\r\n", 4);
if (crlf_offset > (int)max_headerlen ||
(crlf_offset < 0 && buf->datalen > max_headerlen)) {
log_debug(LD_HTTP,"headers too long.");
return -1;
} else if (crlf_offset < 0) {
log_debug(LD_HTTP,"headers not all here yet.");
return 0;
}
/* Okay, we have a full header. Make sure it all appears in the first
* chunk. */
if ((int)buf->head->datalen < crlf_offset + 4)
buf_pullup(buf, crlf_offset+4);
headerlen = crlf_offset + 4;
headers = buf->head->data;
bodylen = buf->datalen - headerlen;
log_debug(LD_HTTP,"headerlen %d, bodylen %d.", (int)headerlen, (int)bodylen);
if (max_headerlen <= headerlen) {
log_warn(LD_HTTP,"headerlen %d larger than %d. Failing.",
(int)headerlen, (int)max_headerlen-1);
return -1;
}
if (max_bodylen <= bodylen) {
log_warn(LD_HTTP,"bodylen %d larger than %d. Failing.",
(int)bodylen, (int)max_bodylen-1);
return -1;
}
#define CONTENT_LENGTH "\r\nContent-Length: "
p = (char*) tor_memstr(headers, headerlen, CONTENT_LENGTH);
if (p) {
int i;
i = atoi(p+strlen(CONTENT_LENGTH));
if (i < 0) {
log_warn(LD_PROTOCOL, "Content-Length is less than zero; it looks like "
"someone is trying to crash us.");
return -1;
}
contentlen = i;
/* if content-length is malformed, then our body length is 0. fine. */
log_debug(LD_HTTP,"Got a contentlen of %d.",(int)contentlen);
if (bodylen < contentlen) {
if (!force_complete) {
log_debug(LD_HTTP,"body not all here yet.");
return 0; /* not all there yet */
}
}
if (bodylen > contentlen) {
bodylen = contentlen;
log_debug(LD_HTTP,"bodylen reduced to %d.",(int)bodylen);
}
}
/* all happy. copy into the appropriate places, and return 1 */
if (headers_out) {
*headers_out = tor_malloc(headerlen+1);
fetch_from_buf(*headers_out, headerlen, buf);
(*headers_out)[headerlen] = 0; /* NUL terminate it */
}
if (body_out) {
tor_assert(body_used);
*body_used = bodylen;
*body_out = tor_malloc(bodylen+1);
fetch_from_buf(*body_out, bodylen, buf);
(*body_out)[bodylen] = 0; /* NUL terminate it */
}
check();
return 1;
}
/**
* Wait this many seconds before warning the user about using SOCKS unsafely
* again (requires that WarnUnsafeSocks is turned on). */
#define SOCKS_WARN_INTERVAL 5
/** Warn that the user application has made an unsafe socks request using
* protocol <b>socks_protocol</b> on port <b>port</b>. Don't warn more than
* once per SOCKS_WARN_INTERVAL, unless <b>safe_socks</b> is set. */
static void
log_unsafe_socks_warning(int socks_protocol, const char *address,
uint16_t port, int safe_socks)
{
static ratelim_t socks_ratelim = RATELIM_INIT(SOCKS_WARN_INTERVAL);
const or_options_t *options = get_options();
if (! options->WarnUnsafeSocks)
return;
if (safe_socks) {
log_fn_ratelim(&socks_ratelim, LOG_WARN, LD_APP,
"Your application (using socks%d to port %d) is giving "
"Tor only an IP address. Applications that do DNS resolves "
"themselves may leak information. Consider using Socks4A "
"(e.g. via privoxy or socat) instead. For more information, "
"please see https://wiki.torproject.org/TheOnionRouter/"
"TorFAQ#SOCKSAndDNS.%s",
socks_protocol,
(int)port,
safe_socks ? " Rejecting." : "");
}
control_event_client_status(LOG_WARN,
"DANGEROUS_SOCKS PROTOCOL=SOCKS%d ADDRESS=%s:%d",
socks_protocol, address, (int)port);
}
/** Do not attempt to parse socks messages longer than this. This value is
* actually significantly higher than the longest possible socks message. */
#define MAX_SOCKS_MESSAGE_LEN 512
/** Return a new socks_request_t. */
socks_request_t *
socks_request_new(void)
{
return tor_malloc_zero(sizeof(socks_request_t));
}
/** Free all storage held in the socks_request_t <b>req</b>. */
void
socks_request_free(socks_request_t *req)
{
if (!req)
return;
if (req->username) {
memwipe(req->username, 0x10, req->usernamelen);
tor_free(req->username);
}
if (req->password) {
memwipe(req->password, 0x04, req->passwordlen);
tor_free(req->password);
}
memwipe(req, 0xCC, sizeof(socks_request_t));
tor_free(req);
}
/** There is a (possibly incomplete) socks handshake on <b>buf</b>, of one
* of the forms
* - socks4: "socksheader username\\0"
* - socks4a: "socksheader username\\0 destaddr\\0"
* - socks5 phase one: "version #methods methods"
* - socks5 phase two: "version command 0 addresstype..."
* If it's a complete and valid handshake, and destaddr fits in
* MAX_SOCKS_ADDR_LEN bytes, then pull the handshake off the buf,
* assign to <b>req</b>, and return 1.
*
* If it's invalid or too big, return -1.
*
* Else it's not all there yet, leave buf alone and return 0.
*
* If you want to specify the socks reply, write it into <b>req->reply</b>
* and set <b>req->replylen</b>, else leave <b>req->replylen</b> alone.
*
* If <b>log_sockstype</b> is non-zero, then do a notice-level log of whether
* the connection is possibly leaking DNS requests locally or not.
*
* If <b>safe_socks</b> is true, then reject unsafe socks protocols.
*
* If returning 0 or -1, <b>req->address</b> and <b>req->port</b> are
* undefined.
*/
int
fetch_from_buf_socks(buf_t *buf, socks_request_t *req,
int log_sockstype, int safe_socks)
{
int res;
ssize_t n_drain;
size_t want_length = 128;
if (buf->datalen < 2) /* version and another byte */
return 0;
do {
n_drain = 0;
buf_pullup(buf, want_length);
tor_assert(buf->head && buf->head->datalen >= 2);
want_length = 0;
res = parse_socks(buf->head->data, buf->head->datalen, req, log_sockstype,
safe_socks, &n_drain, &want_length);
if (n_drain < 0)
buf_clear(buf);
else if (n_drain > 0)
buf_remove_from_front(buf, n_drain);
} while (res == 0 && buf->head && want_length < buf->datalen &&
buf->datalen >= 2);
return res;
}
/** The size of the header of an Extended ORPort message: 2 bytes for
* COMMAND, 2 bytes for BODYLEN */
#define EXT_OR_CMD_HEADER_SIZE 4
/** Read <b>buf</b>, which should contain an Extended ORPort message
* from a transport proxy. If well-formed, create and populate
* <b>out</b> with the Extended ORport message. Return 0 if the
* buffer was incomplete, 1 if it was well-formed and -1 if we
* encountered an error while parsing it. */
int
fetch_ext_or_command_from_buf(buf_t *buf, ext_or_cmd_t **out)
{
char hdr[EXT_OR_CMD_HEADER_SIZE];
uint16_t len;
check();
if (buf->datalen < EXT_OR_CMD_HEADER_SIZE)
return 0;
peek_from_buf(hdr, sizeof(hdr), buf);
len = ntohs(get_uint16(hdr+2));
if (buf->datalen < (unsigned)len + EXT_OR_CMD_HEADER_SIZE)
return 0;
*out = ext_or_cmd_new(len);
(*out)->cmd = ntohs(get_uint16(hdr));
(*out)->len = len;
buf_remove_from_front(buf, EXT_OR_CMD_HEADER_SIZE);
fetch_from_buf((*out)->body, len, buf);
return 1;
}
/** Create a SOCKS5 reply message with <b>reason</b> in its REP field and
* have Tor send it as error response to <b>req</b>.
*/
static void
socks_request_set_socks5_error(socks_request_t *req,
socks5_reply_status_t reason)
{
req->replylen = 10;
memset(req->reply,0,10);
req->reply[0] = 0x05; // VER field.
req->reply[1] = reason; // REP field.
req->reply[3] = 0x01; // ATYP field.
}
/** Implementation helper to implement fetch_from_*_socks. Instead of looking
* at a buffer's contents, we look at the <b>datalen</b> bytes of data in
* <b>data</b>. Instead of removing data from the buffer, we set
* <b>drain_out</b> to the amount of data that should be removed (or -1 if the
* buffer should be cleared). Instead of pulling more data into the first
* chunk of the buffer, we set *<b>want_length_out</b> to the number of bytes
* we'd like to see in the input buffer, if they're available. */
static int
parse_socks(const char *data, size_t datalen, socks_request_t *req,
int log_sockstype, int safe_socks, ssize_t *drain_out,
size_t *want_length_out)
{
unsigned int len;
char tmpbuf[TOR_ADDR_BUF_LEN+1];
tor_addr_t destaddr;
uint32_t destip;
uint8_t socksver;
char *next, *startaddr;
unsigned char usernamelen, passlen;
struct in_addr in;
if (datalen < 2) {
/* We always need at least 2 bytes. */
*want_length_out = 2;
return 0;
}
if (req->socks_version == 5 && !req->got_auth) {
/* See if we have received authentication. Strictly speaking, we should
also check whether we actually negotiated username/password
authentication. But some broken clients will send us authentication
even if we negotiated SOCKS_NO_AUTH. */
if (*data == 1) { /* username/pass version 1 */
/* Format is: authversion [1 byte] == 1
usernamelen [1 byte]
username [usernamelen bytes]
passlen [1 byte]
password [passlen bytes] */
usernamelen = (unsigned char)*(data + 1);
if (datalen < 2u + usernamelen + 1u) {
*want_length_out = 2u + usernamelen + 1u;
return 0;
}
passlen = (unsigned char)*(data + 2u + usernamelen);
if (datalen < 2u + usernamelen + 1u + passlen) {
*want_length_out = 2u + usernamelen + 1u + passlen;
return 0;
}
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 1; /* authversion == 1 */
req->reply[1] = 0; /* authentication successful */
log_debug(LD_APP,
"socks5: Accepted username/password without checking.");
if (usernamelen) {
req->username = tor_memdup(data+2u, usernamelen);
req->usernamelen = usernamelen;
}
if (passlen) {
req->password = tor_memdup(data+3u+usernamelen, passlen);
req->passwordlen = passlen;
}
*drain_out = 2u + usernamelen + 1u + passlen;
req->got_auth = 1;
*want_length_out = 7; /* Minimal socks5 command. */
return 0;
} else if (req->auth_type == SOCKS_USER_PASS) {
/* unknown version byte */
log_warn(LD_APP, "Socks5 username/password version %d not recognized; "
"rejecting.", (int)*data);
return -1;
}
}
socksver = *data;
switch (socksver) { /* which version of socks? */
case 5: /* socks5 */
if (req->socks_version != 5) { /* we need to negotiate a method */
unsigned char nummethods = (unsigned char)*(data+1);
int have_user_pass, have_no_auth;
int r=0;
tor_assert(!req->socks_version);
if (datalen < 2u+nummethods) {
*want_length_out = 2u+nummethods;
return 0;
}
if (!nummethods)
return -1;
req->replylen = 2; /* 2 bytes of response */
req->reply[0] = 5; /* socks5 reply */
have_user_pass = (memchr(data+2, SOCKS_USER_PASS, nummethods) !=NULL);
have_no_auth = (memchr(data+2, SOCKS_NO_AUTH, nummethods) !=NULL);
if (have_user_pass && !(have_no_auth && req->socks_prefer_no_auth)) {
req->auth_type = SOCKS_USER_PASS;
req->reply[1] = SOCKS_USER_PASS; /* tell client to use "user/pass"
auth method */
req->socks_version = 5; /* remember we've already negotiated auth */
log_debug(LD_APP,"socks5: accepted method 2 (username/password)");
r=0;
} else if (have_no_auth) {
req->reply[1] = SOCKS_NO_AUTH; /* tell client to use "none" auth
method */
req->socks_version = 5; /* remember we've already negotiated auth */
log_debug(LD_APP,"socks5: accepted method 0 (no authentication)");
r=0;
} else {
log_warn(LD_APP,
"socks5: offered methods don't include 'no auth' or "
"username/password. Rejecting.");
req->reply[1] = '\xFF'; /* reject all methods */
r=-1;
}
/* Remove packet from buf. Some SOCKS clients will have sent extra
* junk at this point; let's hope it's an authentication message. */
*drain_out = 2u + nummethods;
return r;
}
if (req->auth_type != SOCKS_NO_AUTH && !req->got_auth) {
log_warn(LD_APP,
"socks5: negotiated authentication, but none provided");
return -1;
}
/* we know the method; read in the request */
log_debug(LD_APP,"socks5: checking request");
if (datalen < 7) {/* basic info plus >=1 for addr plus 2 for port */
*want_length_out = 7;
return 0; /* not yet */
}
req->command = (unsigned char) *(data+1);
if (req->command != SOCKS_COMMAND_CONNECT &&
req->command != SOCKS_COMMAND_RESOLVE &&
req->command != SOCKS_COMMAND_RESOLVE_PTR) {
/* not a connect or resolve or a resolve_ptr? we don't support it. */
socks_request_set_socks5_error(req,SOCKS5_COMMAND_NOT_SUPPORTED);
log_warn(LD_APP,"socks5: command %d not recognized. Rejecting.",
req->command);
return -1;
}
switch (*(data+3)) { /* address type */
case 1: /* IPv4 address */
case 4: /* IPv6 address */ {
const int is_v6 = *(data+3) == 4;
const unsigned addrlen = is_v6 ? 16 : 4;
log_debug(LD_APP,"socks5: ipv4 address type");
if (datalen < 6+addrlen) {/* ip/port there? */
*want_length_out = 6+addrlen;
return 0; /* not yet */
}
if (is_v6)
tor_addr_from_ipv6_bytes(&destaddr, data+4);
else
tor_addr_from_ipv4n(&destaddr, get_uint32(data+4));
tor_addr_to_str(tmpbuf, &destaddr, sizeof(tmpbuf), 1);
if (strlen(tmpbuf)+1 > MAX_SOCKS_ADDR_LEN) {
socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR);
log_warn(LD_APP,
"socks5 IP takes %d bytes, which doesn't fit in %d. "
"Rejecting.",
(int)strlen(tmpbuf)+1,(int)MAX_SOCKS_ADDR_LEN);
return -1;
}
strlcpy(req->address,tmpbuf,sizeof(req->address));
req->port = ntohs(get_uint16(data+4+addrlen));
*drain_out = 6+addrlen;
if (req->command != SOCKS_COMMAND_RESOLVE_PTR &&
!addressmap_have_mapping(req->address,0)) {
log_unsafe_socks_warning(5, req->address, req->port, safe_socks);
if (safe_socks) {
socks_request_set_socks5_error(req, SOCKS5_NOT_ALLOWED);
return -1;
}
}
return 1;
}
case 3: /* fqdn */
log_debug(LD_APP,"socks5: fqdn address type");
if (req->command == SOCKS_COMMAND_RESOLVE_PTR) {
socks_request_set_socks5_error(req,
SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED);
log_warn(LD_APP, "socks5 received RESOLVE_PTR command with "
"hostname type. Rejecting.");
return -1;
}
len = (unsigned char)*(data+4);
if (datalen < 7+len) { /* addr/port there? */
*want_length_out = 7+len;
return 0; /* not yet */
}
if (len+1 > MAX_SOCKS_ADDR_LEN) {
socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR);
log_warn(LD_APP,
"socks5 hostname is %d bytes, which doesn't fit in "
"%d. Rejecting.", len+1,MAX_SOCKS_ADDR_LEN);
return -1;
}
memcpy(req->address,data+5,len);
req->address[len] = 0;
req->port = ntohs(get_uint16(data+5+len));
*drain_out = 5+len+2;
if (string_is_valid_ipv4_address(req->address) ||
string_is_valid_ipv6_address(req->address)) {
log_unsafe_socks_warning(5,req->address,req->port,safe_socks);
if (safe_socks) {
socks_request_set_socks5_error(req, SOCKS5_NOT_ALLOWED);
return -1;
}
} else if (!string_is_valid_hostname(req->address)) {
socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR);
log_warn(LD_PROTOCOL,
"Your application (using socks5 to port %d) gave Tor "
"a malformed hostname: %s. Rejecting the connection.",
req->port, escaped_safe_str_client(req->address));
return -1;
}
if (log_sockstype)
log_notice(LD_APP,
"Your application (using socks5 to port %d) instructed "
"Tor to take care of the DNS resolution itself if "
"necessary. This is good.", req->port);
return 1;
default: /* unsupported */
socks_request_set_socks5_error(req,
SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED);
log_warn(LD_APP,"socks5: unsupported address type %d. Rejecting.",
(int) *(data+3));
return -1;
}
tor_assert(0);
case 4: { /* socks4 */
enum {socks4, socks4a} socks4_prot = socks4a;
const char *authstart, *authend;
/* http://ss5.sourceforge.net/socks4.protocol.txt */
/* http://ss5.sourceforge.net/socks4A.protocol.txt */
req->socks_version = 4;
if (datalen < SOCKS4_NETWORK_LEN) {/* basic info available? */
*want_length_out = SOCKS4_NETWORK_LEN;
return 0; /* not yet */
}
// buf_pullup(buf, 1280);
req->command = (unsigned char) *(data+1);
if (req->command != SOCKS_COMMAND_CONNECT &&
req->command != SOCKS_COMMAND_RESOLVE) {
/* not a connect or resolve? we don't support it. (No resolve_ptr with
* socks4.) */
log_warn(LD_APP,"socks4: command %d not recognized. Rejecting.",
req->command);
return -1;
}
req->port = ntohs(get_uint16(data+2));
destip = ntohl(get_uint32(data+4));
if ((!req->port && req->command!=SOCKS_COMMAND_RESOLVE) || !destip) {
log_warn(LD_APP,"socks4: Port or DestIP is zero. Rejecting.");
return -1;
}
if (destip >> 8) {
log_debug(LD_APP,"socks4: destip not in form 0.0.0.x.");
in.s_addr = htonl(destip);
tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
if (strlen(tmpbuf)+1 > MAX_SOCKS_ADDR_LEN) {
log_debug(LD_APP,"socks4 addr (%d bytes) too long. Rejecting.",
(int)strlen(tmpbuf));
return -1;
}
log_debug(LD_APP,
"socks4: successfully read destip (%s)",
safe_str_client(tmpbuf));
socks4_prot = socks4;
}
authstart = data + SOCKS4_NETWORK_LEN;
next = memchr(authstart, 0,
datalen-SOCKS4_NETWORK_LEN);
if (!next) {
if (datalen >= 1024) {
log_debug(LD_APP, "Socks4 user name too long; rejecting.");
return -1;
}
log_debug(LD_APP,"socks4: Username not here yet.");
*want_length_out = datalen+1024; /* More than we need, but safe */
return 0;
}
authend = next;
tor_assert(next < data+datalen);
startaddr = NULL;
if (socks4_prot != socks4a &&
!addressmap_have_mapping(tmpbuf,0)) {
log_unsafe_socks_warning(4, tmpbuf, req->port, safe_socks);
if (safe_socks)
return -1;
}
if (socks4_prot == socks4a) {
if (next+1 == data+datalen) {
log_debug(LD_APP,"socks4: No part of destaddr here yet.");
*want_length_out = datalen + 1024; /* More than we need, but safe */
return 0;
}
startaddr = next+1;
next = memchr(startaddr, 0, data + datalen - startaddr);
if (!next) {
if (datalen >= 1024) {
log_debug(LD_APP,"socks4: Destaddr too long.");
return -1;
}
log_debug(LD_APP,"socks4: Destaddr not all here yet.");
*want_length_out = datalen + 1024; /* More than we need, but safe */
return 0;
}
if (MAX_SOCKS_ADDR_LEN <= next-startaddr) {
log_warn(LD_APP,"socks4: Destaddr too long. Rejecting.");
return -1;
}
// tor_assert(next < buf->cur+buf->datalen);
if (log_sockstype)
log_notice(LD_APP,
"Your application (using socks4a to port %d) instructed "
"Tor to take care of the DNS resolution itself if "
"necessary. This is good.", req->port);
}
log_debug(LD_APP,"socks4: Everything is here. Success.");
strlcpy(req->address, startaddr ? startaddr : tmpbuf,
sizeof(req->address));
if (!tor_strisprint(req->address) || strchr(req->address,'\"')) {
log_warn(LD_PROTOCOL,
"Your application (using socks4 to port %d) gave Tor "
"a malformed hostname: %s. Rejecting the connection.",
req->port, escaped_safe_str_client(req->address));
return -1;
}
if (authend != authstart) {
req->got_auth = 1;
req->usernamelen = authend - authstart;
req->username = tor_memdup(authstart, authend - authstart);
}
/* next points to the final \0 on inbuf */
*drain_out = next - data + 1;
return 1;
}
case 'G': /* get */
case 'H': /* head */
case 'P': /* put/post */
case 'C': /* connect */
strlcpy((char*)req->reply,
"HTTP/1.0 501 Tor is not an HTTP Proxy\r\n"
"Content-Type: text/html; charset=iso-8859-1\r\n\r\n"
"<html>\n"
"<head>\n"
"<title>Tor is not an HTTP Proxy</title>\n"
"</head>\n"
"<body>\n"
"<h1>Tor is not an HTTP Proxy</h1>\n"
"<p>\n"
"It appears you have configured your web browser to use Tor as an HTTP proxy."
"\n"
"This is not correct: Tor is a SOCKS proxy, not an HTTP proxy.\n"
"Please configure your client accordingly.\n"
"</p>\n"
"<p>\n"
"See <a href=\"https://www.torproject.org/documentation.html\">"
"https://www.torproject.org/documentation.html</a> for more "
"information.\n"
"<!-- Plus this comment, to make the body response more than 512 bytes, so "
" IE will be willing to display it. Comment comment comment comment "
" comment comment comment comment comment comment comment comment.-->\n"
"</p>\n"
"</body>\n"
"</html>\n"
, MAX_SOCKS_REPLY_LEN);
req->replylen = strlen((char*)req->reply)+1;
/* fall through */
default: /* version is not socks4 or socks5 */
log_warn(LD_APP,
"Socks version %d not recognized. (Tor is not an http proxy.)",
*(data));
{
/* Tell the controller the first 8 bytes. */
char *tmp = tor_strndup(data, datalen < 8 ? datalen : 8);
control_event_client_status(LOG_WARN,
"SOCKS_UNKNOWN_PROTOCOL DATA=\"%s\"",
escaped(tmp));
tor_free(tmp);
}
return -1;
}
}
/** Inspect a reply from SOCKS server stored in <b>buf</b> according
* to <b>state</b>, removing the protocol data upon success. Return 0 on
* incomplete response, 1 on success and -1 on error, in which case
* <b>reason</b> is set to a descriptive message (free() when finished
* with it).
*
* As a special case, 2 is returned when user/pass is required
* during SOCKS5 handshake and user/pass is configured.
*/
int
fetch_from_buf_socks_client(buf_t *buf, int state, char **reason)
{
ssize_t drain = 0;
int r;
if (buf->datalen < 2)
return 0;
buf_pullup(buf, MAX_SOCKS_MESSAGE_LEN);
tor_assert(buf->head && buf->head->datalen >= 2);
r = parse_socks_client((uint8_t*)buf->head->data, buf->head->datalen,
state, reason, &drain);
if (drain > 0)
buf_remove_from_front(buf, drain);
else if (drain < 0)
buf_clear(buf);
return r;
}
/** Implementation logic for fetch_from_*_socks_client. */
static int
parse_socks_client(const uint8_t *data, size_t datalen,
int state, char **reason,
ssize_t *drain_out)
{
unsigned int addrlen;
*drain_out = 0;
if (datalen < 2)
return 0;
switch (state) {
case PROXY_SOCKS4_WANT_CONNECT_OK:
/* Wait for the complete response */
if (datalen < 8)
return 0;
if (data[1] != 0x5a) {
*reason = tor_strdup(socks4_response_code_to_string(data[1]));
return -1;
}
/* Success */
*drain_out = 8;
return 1;
case PROXY_SOCKS5_WANT_AUTH_METHOD_NONE:
/* we don't have any credentials */
if (data[1] != 0x00) {
*reason = tor_strdup("server doesn't support any of our "
"available authentication methods");
return -1;
}
log_info(LD_NET, "SOCKS 5 client: continuing without authentication");
*drain_out = -1;
return 1;
case PROXY_SOCKS5_WANT_AUTH_METHOD_RFC1929:
/* we have a username and password. return 1 if we can proceed without
* providing authentication, or 2 otherwise. */
switch (data[1]) {
case 0x00:
log_info(LD_NET, "SOCKS 5 client: we have auth details but server "
"doesn't require authentication.");
*drain_out = -1;
return 1;
case 0x02:
log_info(LD_NET, "SOCKS 5 client: need authentication.");
*drain_out = -1;
return 2;
/* fall through */
}
*reason = tor_strdup("server doesn't support any of our available "
"authentication methods");
return -1;
case PROXY_SOCKS5_WANT_AUTH_RFC1929_OK:
/* handle server reply to rfc1929 authentication */
if (data[1] != 0x00) {
*reason = tor_strdup("authentication failed");
return -1;
}
log_info(LD_NET, "SOCKS 5 client: authentication successful.");
*drain_out = -1;
return 1;
case PROXY_SOCKS5_WANT_CONNECT_OK:
/* response is variable length. BND.ADDR, etc, isn't needed
* (don't bother with buf_pullup()), but make sure to eat all
* the data used */
/* wait for address type field to arrive */
if (datalen < 4)
return 0;
switch (data[3]) {
case 0x01: /* ip4 */
addrlen = 4;
break;
case 0x04: /* ip6 */
addrlen = 16;
break;
case 0x03: /* fqdn (can this happen here?) */
if (datalen < 5)
return 0;
addrlen = 1 + data[4];
break;
default:
*reason = tor_strdup("invalid response to connect request");
return -1;
}
/* wait for address and port */
if (datalen < 6 + addrlen)
return 0;
if (data[1] != 0x00) {
*reason = tor_strdup(socks5_response_code_to_string(data[1]));
return -1;
}
*drain_out = 6 + addrlen;
return 1;
}
/* shouldn't get here... */
tor_assert(0);
return -1;
}
/** Return 1 iff buf looks more like it has an (obsolete) v0 controller
* command on it than any valid v1 controller command. */
int
peek_buf_has_control0_command(buf_t *buf)
{
if (buf->datalen >= 4) {
char header[4];
uint16_t cmd;
peek_from_buf(header, sizeof(header), buf);
cmd = ntohs(get_uint16(header+2));
if (cmd <= 0x14)
return 1; /* This is definitely not a v1 control command. */
}
return 0;
}
/** Return the index within <b>buf</b> at which <b>ch</b> first appears,
* or -1 if <b>ch</b> does not appear on buf. */
static off_t
buf_find_offset_of_char(buf_t *buf, char ch)
{
chunk_t *chunk;
off_t offset = 0;
for (chunk = buf->head; chunk; chunk = chunk->next) {
char *cp = memchr(chunk->data, ch, chunk->datalen);
if (cp)
return offset + (cp - chunk->data);
else
offset += chunk->datalen;
}
return -1;
}
/** Try to read a single LF-terminated line from <b>buf</b>, and write it
* (including the LF), NUL-terminated, into the *<b>data_len</b> byte buffer
* at <b>data_out</b>. Set *<b>data_len</b> to the number of bytes in the
* line, not counting the terminating NUL. Return 1 if we read a whole line,
* return 0 if we don't have a whole line yet, and return -1 if the line
* length exceeds *<b>data_len</b>.
*/
int
fetch_from_buf_line(buf_t *buf, char *data_out, size_t *data_len)
{
size_t sz;
off_t offset;
if (!buf->head)
return 0;
offset = buf_find_offset_of_char(buf, '\n');
if (offset < 0)
return 0;
sz = (size_t) offset;
if (sz+2 > *data_len) {
*data_len = sz + 2;
return -1;
}
fetch_from_buf(data_out, sz+1, buf);
data_out[sz+1] = '\0';
*data_len = sz+1;
return 1;
}
/** Compress on uncompress the <b>data_len</b> bytes in <b>data</b> using the
* zlib state <b>state</b>, appending the result to <b>buf</b>. If
* <b>done</b> is true, flush the data in the state and finish the
* compression/uncompression. Return -1 on failure, 0 on success. */
int
write_to_buf_zlib(buf_t *buf, tor_zlib_state_t *state,
const char *data, size_t data_len,
int done)
{
char *next;
size_t old_avail, avail;
int over = 0;
do {
int need_new_chunk = 0;
if (!buf->tail || ! CHUNK_REMAINING_CAPACITY(buf->tail)) {
size_t cap = data_len / 4;
buf_add_chunk_with_capacity(buf, cap, 1);
}
next = CHUNK_WRITE_PTR(buf->tail);
avail = old_avail = CHUNK_REMAINING_CAPACITY(buf->tail);
switch (tor_zlib_process(state, &next, &avail, &data, &data_len, done)) {
case TOR_ZLIB_DONE:
over = 1;
break;
case TOR_ZLIB_ERR:
return -1;
case TOR_ZLIB_OK:
if (data_len == 0)
over = 1;
break;
case TOR_ZLIB_BUF_FULL:
if (avail) {
/* Zlib says we need more room (ZLIB_BUF_FULL). Start a new chunk
* automatically, whether were going to or not. */
need_new_chunk = 1;
}
break;
}
buf->datalen += old_avail - avail;
buf->tail->datalen += old_avail - avail;
if (need_new_chunk) {
buf_add_chunk_with_capacity(buf, data_len/4, 1);
}
} while (!over);
check();
return 0;
}
/** Set *<b>output</b> to contain a copy of the data in *<b>input</b> */
int
buf_set_to_copy(buf_t **output,
const buf_t *input)
{
if (*output)
buf_free(*output);
*output = buf_copy(input);
return 0;
}
/** Log an error and exit if <b>buf</b> is corrupted.
*/
void
assert_buf_ok(buf_t *buf)
{
tor_assert(buf);
tor_assert(buf->magic == BUFFER_MAGIC);
if (! buf->head) {
tor_assert(!buf->tail);
tor_assert(buf->datalen == 0);
} else {
chunk_t *ch;
size_t total = 0;
tor_assert(buf->tail);
for (ch = buf->head; ch; ch = ch->next) {
total += ch->datalen;
tor_assert(ch->datalen <= ch->memlen);
tor_assert(ch->data >= &ch->mem[0]);
tor_assert(ch->data <= &ch->mem[0]+ch->memlen);
if (ch->data == &ch->mem[0]+ch->memlen) {
static int warned = 0;
if (! warned) {
log_warn(LD_BUG, "Invariant violation in buf.c related to #15083");
warned = 1;
}
}
tor_assert(ch->data+ch->datalen <= &ch->mem[0] + ch->memlen);
if (!ch->next)
tor_assert(ch == buf->tail);
}
tor_assert(buf->datalen == total);
}
}
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