/** Construct and return a tor_zlib_state_t object using <b>method</b>. If
* <b>compress</b>, it's for compression; otherwise it's for
* decompression. */
tor_zlib_state_t *
tor_zlib_new(int compress, compress_method_t method)
{
tor_zlib_state_t *out;
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in inflateInit2 */
log_warn(LD_BUG, "Gzip not supported with zlib %s", ZLIB_VERSION);
return NULL;
}
out = tor_malloc_zero(sizeof(tor_zlib_state_t));
out->stream.zalloc = Z_NULL;
out->stream.zfree = Z_NULL;
out->stream.opaque = NULL;
out->compress = compress;
if (compress) {
if (deflateInit2(&out->stream, Z_BEST_COMPRESSION, Z_DEFLATED,
method_bits(method), 8, Z_DEFAULT_STRATEGY) != Z_OK)
goto err;
} else {
if (inflateInit2(&out->stream, method_bits(method)) != Z_OK)
goto err;
}
return out;
err:
tor_free(out);
return NULL;
}
/** Construct and return a tor_zlib_state_t object using <b>method</b>. If
* <b>compress</b>, it's for compression; otherwise it's for
* decompression. */
tor_zlib_state_t *
tor_zlib_new(int compress, compress_method_t method,
zlib_compression_level_t compression_level)
{
tor_zlib_state_t *out;
int bits, memlevel;
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in inflateInit2 */
log_warn(LD_BUG, "Gzip not supported with zlib %s", ZLIB_VERSION);
return NULL;
}
if (! compress) {
/* use this setting for decompression, since we might have the
* max number of window bits */
compression_level = HIGH_COMPRESSION;
}
out = tor_malloc_zero(sizeof(tor_zlib_state_t));
out->stream.zalloc = Z_NULL;
out->stream.zfree = Z_NULL;
out->stream.opaque = NULL;
out->compress = compress;
bits = method_bits(method, compression_level);
memlevel = get_memlevel(compression_level);
if (compress) {
if (deflateInit2(&out->stream, Z_BEST_COMPRESSION, Z_DEFLATED,
bits, memlevel,
Z_DEFAULT_STRATEGY) != Z_OK)
goto err;
} else {
if (inflateInit2(&out->stream, bits) != Z_OK)
goto err;
}
out->allocation = tor_zlib_state_size_precalc(!compress, bits, memlevel);
total_zlib_allocation += out->allocation;
return out;
err:
tor_free(out);
return NULL;
}
/** Given zero or more zlib-compressed or gzip-compressed strings of
* total length
* <b>in_len</b> bytes at <b>in</b>, uncompress them into a newly allocated
* buffer, using the method described in <b>method</b>. Store the uncompressed
* string in *<b>out</b>, and its length in *<b>out_len</b>. Return 0 on
* success, -1 on failure.
*
* If <b>complete_only</b> is true, we consider a truncated input as a
* failure; otherwise we decompress as much as we can. Warn about truncated
* or corrupt inputs at <b>protocol_warn_level</b>.
*/
int
tor_gzip_uncompress(char **out, size_t *out_len,
const char *in, size_t in_len,
compress_method_t method,
int complete_only,
int protocol_warn_level)
{
struct z_stream_s *stream = NULL;
size_t out_size, old_size;
off_t offset;
int r;
tor_assert(out);
tor_assert(out_len);
tor_assert(in);
tor_assert(in_len < UINT_MAX);
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in inflateInit2 */
log_warn(LD_BUG, "Gzip not supported with zlib %s", ZLIB_VERSION);
return -1;
}
*out = NULL;
stream = tor_malloc_zero(sizeof(struct z_stream_s));
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
stream->opaque = NULL;
stream->next_in = (unsigned char*) in;
stream->avail_in = (unsigned int)in_len;
if (inflateInit2(stream,
method_bits(method, HIGH_COMPRESSION)) != Z_OK) {
log_warn(LD_GENERAL, "Error from inflateInit2: %s",
stream->msg?stream->msg:"<no message>");
goto err;
}
out_size = in_len * 2; /* guess 50% compression. */
if (out_size < 1024) out_size = 1024;
if (out_size >= SIZE_T_CEILING || out_size > UINT_MAX)
goto err;
*out = tor_malloc(out_size);
stream->next_out = (unsigned char*)*out;
stream->avail_out = (unsigned int)out_size;
while (1) {
switch (inflate(stream, complete_only ? Z_FINISH : Z_SYNC_FLUSH))
{
case Z_STREAM_END:
if (stream->avail_in == 0)
goto done;
/* There may be more compressed data here. */
if ((r = inflateEnd(stream)) != Z_OK) {
log_warn(LD_BUG, "Error freeing gzip structures");
goto err;
}
if (inflateInit2(stream,
method_bits(method,HIGH_COMPRESSION)) != Z_OK) {
log_warn(LD_GENERAL, "Error from second inflateInit2: %s",
stream->msg?stream->msg:"<no message>");
goto err;
}
break;
case Z_OK:
if (!complete_only && stream->avail_in == 0)
goto done;
/* In case zlib doesn't work as I think.... */
if (stream->avail_out >= stream->avail_in+16)
break;
case Z_BUF_ERROR:
if (stream->avail_out > 0) {
log_fn(protocol_warn_level, LD_PROTOCOL,
"possible truncated or corrupt zlib data");
goto err;
}
offset = stream->next_out - (unsigned char*)*out;
old_size = out_size;
out_size *= 2;
if (out_size < old_size) {
log_warn(LD_GENERAL, "Size overflow in uncompression.");
goto err;
}
if (is_compression_bomb(in_len, out_size)) {
log_warn(LD_GENERAL, "Input looks like a possible zlib bomb; "
"not proceeding.");
goto err;
}
if (out_size >= SIZE_T_CEILING) {
log_warn(LD_BUG, "Hit SIZE_T_CEILING limit while uncompressing.");
goto err;
}
*out = tor_realloc(*out, out_size);
stream->next_out = (unsigned char*)(*out + offset);
if (out_size - offset > UINT_MAX) {
log_warn(LD_BUG, "Ran over unsigned int limit of zlib while "
"uncompressing.");
goto err;
}
stream->avail_out = (unsigned int)(out_size - offset);
break;
default:
log_warn(LD_GENERAL, "Gzip decompression returned an error: %s",
stream->msg ? stream->msg : "<no message>");
goto err;
}
}
done:
*out_len = stream->next_out - (unsigned char*)*out;
r = inflateEnd(stream);
tor_free(stream);
if (r != Z_OK) {
log_warn(LD_BUG, "Error freeing gzip structures");
goto err;
}
/* NUL-terminate output. */
if (out_size == *out_len)
*out = tor_realloc(*out, out_size + 1);
(*out)[*out_len] = '\0';
return 0;
err:
if (stream) {
inflateEnd(stream);
tor_free(stream);
}
if (*out) {
tor_free(*out);
}
return -1;
}
/** Given <b>in_len</b> bytes at <b>in</b>, compress them into a newly
* allocated buffer, using the method described in <b>method</b>. Store the
* compressed string in *<b>out</b>, and its length in *<b>out_len</b>.
* Return 0 on success, -1 on failure.
*/
int
tor_gzip_compress(char **out, size_t *out_len,
const char *in, size_t in_len,
compress_method_t method)
{
struct z_stream_s *stream = NULL;
size_t out_size, old_size;
off_t offset;
tor_assert(out);
tor_assert(out_len);
tor_assert(in);
tor_assert(in_len < UINT_MAX);
*out = NULL;
if (method == GZIP_METHOD && !is_gzip_supported()) {
/* Old zlib version don't support gzip in deflateInit2 */
log_warn(LD_BUG, "Gzip not supported with zlib %s", ZLIB_VERSION);
goto err;
}
stream = tor_malloc_zero(sizeof(struct z_stream_s));
stream->zalloc = Z_NULL;
stream->zfree = Z_NULL;
stream->opaque = NULL;
stream->next_in = (unsigned char*) in;
stream->avail_in = (unsigned int)in_len;
if (deflateInit2(stream, Z_BEST_COMPRESSION, Z_DEFLATED,
method_bits(method, HIGH_COMPRESSION),
get_memlevel(HIGH_COMPRESSION),
Z_DEFAULT_STRATEGY) != Z_OK) {
log_warn(LD_GENERAL, "Error from deflateInit2: %s",
stream->msg?stream->msg:"<no message>");
goto err;
}
/* Guess 50% compression. */
out_size = in_len / 2;
if (out_size < 1024) out_size = 1024;
*out = tor_malloc(out_size);
stream->next_out = (unsigned char*)*out;
stream->avail_out = (unsigned int)out_size;
while (1) {
switch (deflate(stream, Z_FINISH))
{
case Z_STREAM_END:
goto done;
case Z_OK:
/* In case zlib doesn't work as I think .... */
if (stream->avail_out >= stream->avail_in+16)
break;
case Z_BUF_ERROR:
offset = stream->next_out - ((unsigned char*)*out);
old_size = out_size;
out_size *= 2;
if (out_size < old_size) {
log_warn(LD_GENERAL, "Size overflow in compression.");
goto err;
}
*out = tor_realloc(*out, out_size);
stream->next_out = (unsigned char*)(*out + offset);
if (out_size - offset > UINT_MAX) {
log_warn(LD_BUG, "Ran over unsigned int limit of zlib while "
"uncompressing.");
goto err;
}
stream->avail_out = (unsigned int)(out_size - offset);
break;
default:
log_warn(LD_GENERAL, "Gzip compression didn't finish: %s",
stream->msg ? stream->msg : "<no message>");
goto err;
}
}
done:
*out_len = stream->total_out;
#ifdef OPENBSD
/* "Hey Rocky! Watch me change an unsigned field to a signed field in a
* third-party API!"
* "Oh, that trick will just make people do unsafe casts to the unsigned
* type in their cross-platform code!"
* "Don't be foolish. I'm _sure_ they'll have the good sense to make sure
* the newly unsigned field isn't negative." */
tor_assert(stream->total_out >= 0);
#endif
if (((size_t)stream->total_out) > out_size + 4097) {
/* If we're wasting more than 4k, don't. */
*out = tor_realloc(*out, stream->total_out + 1);
}
if (deflateEnd(stream)!=Z_OK) {
log_warn(LD_BUG, "Error freeing gzip structures");
goto err;
}
tor_free(stream);
if (is_compression_bomb(*out_len, in_len)) {
log_warn(LD_BUG, "We compressed something and got an insanely high "
"compression factor; other Tors would think this was a zlib bomb.");
goto err;
}
return 0;
err:
if (stream) {
deflateEnd(stream);
tor_free(stream);
}
tor_free(*out);
return -1;
}
