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[stegotorus/master] changed pdfwrap and pdfunwrap to use zlib to encode data in stream objects
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit e1024c2d7e14fad7f832454326a4a9ea94e1e736 Author: Steven Cheung <steven.cheung(a)sri.com> Date: Sun Jun 10 06:49:45 2012 -0700 changed pdfwrap and pdfunwrap to use zlib to encode data in stream objects --- src/steg/pdfSteg.cc | 180 ++++++++++++++++++++++++++++++++------------------ 1 files changed, 115 insertions(+), 65 deletions(-) diff --git a/src/steg/pdfSteg.cc b/src/steg/pdfSteg.cc index 658c319..2f67051 100644 --- a/src/steg/pdfSteg.cc +++ b/src/steg/pdfSteg.cc @@ -7,19 +7,21 @@ #include "connections.h" #include "payloads.h" #include <event2/buffer.h> +#include "compression.h" /* pdfSteg: A PDF-based steganography module */ #define PDF_DELIMITER '?' #define PDF_DELIMITER2 '.' -#define STREAM_BEGIN ">>stream" -#define STREAM_BEGIN_SIZE 8 +#define STREAM_BEGIN "stream" +#define STREAM_BEGIN_SIZE 6 #define STREAM_END "endstream" #define STREAM_END_SIZE 9 #define DEBUG + /* * pdf_add_delimiter processes the input buffer (inbuf) of length * inbuflen, copies it to output buffer (outbuf) of size outbufsize, @@ -158,6 +160,38 @@ pdf_remove_delimiter(const char *inbuf, size_t inbuflen, return cnt; } + +/* + * strInBinaryRewind looks for char array pattern of length patternLen + * in a char array blob of length blobLen in the *reverse* direction + * + * return a pointer for the first occurrence of pattern in blob, + * starting from the end of blob, if found; otherwise, return NULL + * + */ +char * +strInBinaryRewind (const char *pattern, unsigned int patternLen, + const char *blob, unsigned int blobLen) { + int found = 0; + char *cp; + + if (patternLen < 1 || blobLen < 1) return 0; + cp = (char *) blob + blobLen - 1; + while (cp >= blob) { + if (cp - (patternLen-1) < blob) break; + if (*cp == pattern[patternLen-1]) { + if (memcmp(cp-(patternLen-1), pattern, patternLen-1) == 0) { + found = 1; + break; + } + } + cp--; + } + if (found) return (cp-(patternLen-1)); + else return NULL; +} + + /* * pdf_wrap embeds data of length dlen inside the stream objects of the PDF * document (length plen) that appears in the body of a HTTP msg, and @@ -172,29 +206,30 @@ pdf_wrap(const char *data, size_t dlen, const char *pdfTemplate, size_t plen, char *outbuf, size_t outbufsize) { - char data2[dlen*2+2]; - const char *tp, *dp, *plimit; - char *op, *streamStart, *streamEnd; - size_t data2len, cnt, size, size2; - ssize_t rv; + int data2size = 2*dlen+10; + // see rfc 1950 for zlib format, in addition to compressed data, we have + // 2-byte compression method and flags + + // 4-byte dict ID + + // 4-byte ADLER32 checksum + char data2[data2size]; + const char *tp, *plimit; + char *op, *streamStart, *streamEnd, *filterStart; + size_t data2len, size; + int np; if (dlen > SIZE_T_CEILING || plen > SIZE_T_CEILING || outbufsize > SIZE_T_CEILING) return -1; - // assumption: pdf_wrap is length-preserving - if (outbufsize < plen) return -1; - - rv = pdf_add_delimiter(data, dlen, data2, HTTP_MSG_BUF_SIZE, - PDF_DELIMITER, PDF_DELIMITER2); - if (rv < 1) + data2len = compress((const uint8_t *)data, dlen, + (uint8_t *)data2, data2size, c_format_zlib); + if ((int)data2len < 0) { + log_warn("compress failed and returned %lu", data2len); return -1; - data2len = rv; + } op = outbuf; // current pointer for output buffer tp = pdfTemplate; // current pointer for http msg template - dp = data2; // current pointer for data2 - cnt = 0; // number of data char encoded plimit = pdfTemplate+plen; while (tp < plimit) { @@ -205,43 +240,47 @@ pdf_wrap(const char *data, size_t dlen, return -1; } - // copy everything between tp and "stream" (inclusive) to outbuf - size = streamStart - tp + STREAM_BEGIN_SIZE; - memcpy(op, tp, size); - op += size; - tp = streamStart + STREAM_BEGIN_SIZE; - streamEnd = strInBinary(STREAM_END, STREAM_END_SIZE, tp, plimit-tp); if (streamEnd == NULL) { log_warn("Cannot find endstream in pdf"); return -1; } - // count the number of usable char between tp and streamEnd - size = streamEnd-tp; - - // encoding data in the stream obj - if (size > 0) { - size2 = data2len - cnt; - if (size < size2) { - memcpy(op, dp, size); - op += size; tp += size; dp += size; - memcpy(op, tp, STREAM_END_SIZE); - op += STREAM_END_SIZE; tp += STREAM_END_SIZE; - cnt += size; - } else { // done encoding data - memcpy(op, dp, size2); - op += size2; tp += size2; dp += size2; - cnt += size2; - break; - } - log_debug("Encoded %lu bytes in pdf", (unsigned long)size); - } else { // empty stream - memcpy(op, tp, STREAM_END_SIZE); - op += STREAM_END_SIZE; tp += STREAM_END_SIZE; + filterStart = strInBinaryRewind(" obj", 4, tp, streamStart-tp); + if (filterStart == NULL) { + log_warn("Cannot find obj\n"); + return -1; + } else { + // copy everything between tp and up and and including "obj" to outbuf + size = filterStart - tp + 4; + memcpy(op, tp, size); + op[size] = 0; + op += size; + + // write meta-data for stream object + np = sprintf(op, " <<\n/Length %d\n/Filter /FlateDecode\n>>\nstream\n", (int)data2len); + if (np < 0) { + log_warn("sprintf failed\n"); + return -1; + } + op += np; + + // copy compressed data to outbuf + memcpy(op, data2, data2len); + op += data2len; + + // write endstream to outbuf + np = sprintf(op, "\nendstream"); + if (np < 0) { + log_warn("sprintf failed\n"); + return -1; + } + op += np; } - if (cnt >= data2len) break; // this shouldn't happen ... + // done with encoding data + tp = streamEnd+STREAM_END_SIZE; + break; } // copy the rest of pdfTemplate to outbuf @@ -261,9 +300,11 @@ pdf_unwrap(const char *data, size_t dlen, char *outbuf, size_t outbufsize) { const char *dp, *dlimit; - char *op, *streamStart, *streamEnd, *olimit; + char *op, *streamStart, *streamEnd; size_t cnt, size, size2; - bool endFlag, escape = false; + + int streamObjStartSkip=0; + int streamObjEndSkip=0; if (dlen > SIZE_T_CEILING || outbufsize > SIZE_T_CEILING) return -1; @@ -272,8 +313,8 @@ pdf_unwrap(const char *data, size_t dlen, op = outbuf; // current pointer for outbuf cnt = 0; // number of char decoded dlimit = data+dlen; - olimit = outbuf+outbufsize; + while (dp < dlimit) { // find the next stream obj streamStart = strInBinary(STREAM_BEGIN, STREAM_BEGIN_SIZE, dp, dlimit-dp); @@ -283,31 +324,40 @@ pdf_unwrap(const char *data, size_t dlen, } dp = streamStart + STREAM_BEGIN_SIZE; + + // streamObjStartSkip = size of end-of-line (EOL) char(s) after ">>stream" + if ( *dp == '\r' && *(dp+1) == '\n' ) { // Windows-style EOL + streamObjStartSkip = 2; + } else if ( *dp == '\n' ) { // Unix-style EOL + streamObjStartSkip = 1; + } + + dp = dp + streamObjStartSkip; + streamEnd = strInBinary(STREAM_END, STREAM_END_SIZE, dp, dlimit-dp); if (streamEnd == NULL) { log_warn("Cannot find endstream in pdf"); return -1; } - // count the number of usable char between tp and streamEnd - size = streamEnd-dp; + // streamObjEndSkip = size of end-of-line (EOL) char(s) at the end of stream obj + if (*(streamEnd-2) == '\r' && *(streamEnd-1) == '\n') { + streamObjEndSkip = 2; + } else if (*(streamEnd-1) == '\n') { + streamObjEndSkip = 1; + } - if (size > 0) { - ssize_t rv = pdf_remove_delimiter(dp, size, op, olimit-op, PDF_DELIMITER, - &endFlag, &escape); - if (rv < 0) - return -1; + // compute the size of stream obj payload + size = (streamEnd-streamObjEndSkip) - dp; - size2 = rv; - cnt += size2; - if (endFlag) { // Done decoding - break; - } else { // Continue decoding - op += size2; - dp = streamEnd + STREAM_END_SIZE; - } - } else { // empty stream obj - dp = streamEnd + STREAM_END_SIZE; + size2 = decompress((const uint8_t *)dp, size, (uint8_t *)op, outbufsize); + if ((int)size2 < 0) { + log_warn("decompress failed; size2 = %d\n", (int)size2); + return -1; + } else { + op += size2; + cnt = size2; + break; // done decoding } }

1 0

[stegotorus/master] fixed test data for test_pdf_wrap_unwrap()
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit cd8e68731a8a4a536ba28758e0538d53bb6afc94 Author: Steven Cheung <steven.cheung(a)sri.com> Date: Sun Jun 10 11:26:36 2012 -0700 fixed test data for test_pdf_wrap_unwrap() --- src/test/unittest_pdfsteg.cc | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/src/test/unittest_pdfsteg.cc b/src/test/unittest_pdfsteg.cc index 36a1167..7333fbc 100644 --- a/src/test/unittest_pdfsteg.cc +++ b/src/test/unittest_pdfsteg.cc @@ -36,8 +36,7 @@ static void test_pdf_wrap_unwrap(void *) { const char *pdf = - "[PDFHDR][STUFFS1]>>streamABCDEFGHIJYYendstream" - "[STUFFS2]>>streamABCDEFGHIJYYendstream[STUFF3][PDFTRAILER]"; + "[PDFHDR][STUFFS1]1 0 obj <<\n/Length 12\n/Filter /FlateDecode\n>>\nstream\nABCDEFGHIJYY>>endstream\n[STUFF2][PDFTRAILER]"; const char *const tests[] = { "12345", @@ -61,7 +60,6 @@ test_pdf_wrap_unwrap(void *) out, sizeof out); tt_int_op(rv, >, 0); r1 = rv; - tt_int_op(r1, ==, strlen(pdf)); rv = pdf_unwrap(out, r1, orig, sizeof orig); tt_int_op(rv, >, 0);

1 0

[stegotorus/master] fixing compiler errors when on 32-bit machine and explicit casts for log messages are needed
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit a0b21894457ef2ea4a3f98d7a1bd4a54861f2967 Author: Linda Briesemeister <linda.briesemeister(a)sri.com> Date: Mon Jun 11 12:29:34 2012 -0500 fixing compiler errors when on 32-bit machine and explicit casts for log messages are needed --- src/protocol/null.cc | 4 ++-- src/steg/embed.cc | 8 ++++---- src/steg/http.cc | 2 +- src/steg/pdfSteg.cc | 2 +- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/src/protocol/null.cc b/src/protocol/null.cc index d8fe98b..c5ec831 100644 --- a/src/protocol/null.cc +++ b/src/protocol/null.cc @@ -196,7 +196,7 @@ int null_circuit_t::send() { log_debug(this, "sending %lu bytes", - evbuffer_get_length(bufferevent_get_input(this->up_buffer))); + (unsigned long)evbuffer_get_length(bufferevent_get_input(this->up_buffer))); return evbuffer_add_buffer(this->downstream->outbound(), bufferevent_get_input(this->up_buffer)); @@ -268,7 +268,7 @@ int null_conn_t::recv() { log_assert(this->upstream); - log_debug(this, "receiving %lu bytes", evbuffer_get_length(this->inbound())); + log_debug(this, "receiving %lu bytes", (unsigned long)evbuffer_get_length(this->inbound())); return evbuffer_add_buffer(bufferevent_get_output(this->upstream->up_buffer), this->inbound()); } diff --git a/src/steg/embed.cc b/src/steg/embed.cc index 327c7c4..463148d 100644 --- a/src/steg/embed.cc +++ b/src/steg/embed.cc @@ -82,15 +82,15 @@ embed_steg_config_t::embed_steg_config_t(config_t *cfg) for (vector<trace_t>::iterator p = traces.begin(); p != traces.end(); ++p) { int num_pkt; if (fscanf(trace_file, "%d", &num_pkt) < 1) - log_abort("couldn't read number of packets in trace %ld", - p - traces.begin()); + log_abort("couldn't read number of packets in trace %li", + (long)(p - traces.begin())); p->pkt_sizes.resize(num_pkt); p->pkt_times.resize(num_pkt); for (int i = 0; i < num_pkt; i++) if (fscanf(trace_file, "%hd %d", &p->pkt_sizes[i], &p->pkt_times[i]) < 1) - log_abort("couldn't read trace entry %ld/%d", - p - traces.begin(), i); + log_abort("couldn't read trace entry %li/%d", + (long)(p - traces.begin()), i); } log_debug("read %d traces", num_traces); diff --git a/src/steg/http.cc b/src/steg/http.cc index cfeaf93..171bdcb 100644 --- a/src/steg/http.cc +++ b/src/steg/http.cc @@ -329,7 +329,7 @@ http_client_cookie_transmit (http_steg_t *s, struct evbuffer *source, return -1; } log_debug(conn, "cookie input %ld encoded %d final %d", - sbuflen, len, cookie_len); + (long)sbuflen, len, cookie_len); log_debug(conn, "cookie encoded: %s", data2); log_debug(conn, "cookie final: %s", cookiebuf); diff --git a/src/steg/pdfSteg.cc b/src/steg/pdfSteg.cc index 2f67051..f76da99 100644 --- a/src/steg/pdfSteg.cc +++ b/src/steg/pdfSteg.cc @@ -224,7 +224,7 @@ pdf_wrap(const char *data, size_t dlen, data2len = compress((const uint8_t *)data, dlen, (uint8_t *)data2, data2size, c_format_zlib); if ((int)data2len < 0) { - log_warn("compress failed and returned %lu", data2len); + log_warn("compress failed and returned %lu", (unsigned long)data2len); return -1; }

1 0

[stegotorus/master] Accept and ignore --server-key
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit e3a7a80ff7666f836b921c343ef8bf28ffe886f6 Author: Zack Weinberg <zackw(a)cmu.edu> Date: Tue Jun 12 17:48:56 2012 -0400 Accept and ignore --server-key --- src/protocol/chop.cc | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index f547303..67ed2b3 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -428,6 +428,13 @@ chop_config_t::init(int n_options, const char *const *options) } else goto usage; + // if in client mode, accept and ignore --server-key= + if (mode != LSN_SIMPLE_SERVER && + !strncmp(options[1], "--server-key=", 13)) { + options++; + n_options--; + } + up_address = resolve_address_port(options[1], 1, listen_up, defport); if (!up_address) { log_warn("chop: invalid up address: %s", options[1]);

1 0

[stegotorus/master] Two subtle chopper bugfixes:
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit 4f3ccfc31308ea4703300cbbfeb7a463eb0d9dfb Author: Zack Weinberg <zackw(a)cmu.edu> Date: Wed Jun 13 17:29:17 2012 -0400 Two subtle chopper bugfixes: * Don't kill the connection just because not enough data has arrived yet for us to desteg the handshake message. * If there's no data to send, but there is an EOF to send, and none of the existing connections can send, we need to open a new connection. --- src/protocol/chop.cc | 23 +++++++++++++++-------- 1 files changed, 15 insertions(+), 8 deletions(-) diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index 20ba563..a30dd94 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -705,14 +705,16 @@ chop_circuit_t::send() dead_cycles++; log_debug(this, "%u dead cycles", dead_cycles); - // If there was real data and we didn't make any progress on it, - // or if there are no downstream connections at all, and we're the - // client, try opening new connections. If we're the server, we - // have to just twiddle our thumbs and hope the client does that. - // Note that due to the sliding window of receive blocks, there is - // a hard upper limit of 127 outstanding connections (that is, - // half the receive window). - if ((avail0 > 0 && downstreams.size() < 127) || downstreams.empty()) { + // If there was real data or an EOF to send, and we didn't make + // any progress on it, or if there are no downstream connections + // at all, and we're the client, try opening new connections. If + // we're the server, we have to just twiddle our thumbs and hope + // the client does that. Note that due to the sliding window of + // receive blocks, there is a hard upper limit of 127 outstanding + // connections (that is, half the receive window). + if (downstreams.empty() || + (downstreams.size() < 127 && + (avail0 > 0 || (upstream_eof && !sent_fin)))) { if (config->mode != LSN_SIMPLE_SERVER) circuit_reopen_downstreams(this); else @@ -1213,6 +1215,11 @@ chop_conn_t::recv() if (steg->receive(recv_pending)) return -1; + // If that succeeded but did not copy anything into recv_pending, + // wait for more data. + if (evbuffer_get_length(recv_pending) == 0) + return 0; + if (!upstream) { // Try to receive a handshake. if (recv_handshake())

1 0

[stegotorus/master] Minor code-formatting fixes.
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit 9526b5db6ed5281dade13e4914087f49d7d16d2a Author: Zack Weinberg <zackw(a)cmu.edu> Date: Wed Jun 13 11:24:12 2012 -0400 Minor code-formatting fixes. --- src/protocol/null.cc | 3 ++- src/steg/embed.cc | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/src/protocol/null.cc b/src/protocol/null.cc index c5ec831..ca6cc74 100644 --- a/src/protocol/null.cc +++ b/src/protocol/null.cc @@ -268,7 +268,8 @@ int null_conn_t::recv() { log_assert(this->upstream); - log_debug(this, "receiving %lu bytes", (unsigned long)evbuffer_get_length(this->inbound())); + log_debug(this, "receiving %lu bytes", + (unsigned long)evbuffer_get_length(this->inbound())); return evbuffer_add_buffer(bufferevent_get_output(this->upstream->up_buffer), this->inbound()); } diff --git a/src/steg/embed.cc b/src/steg/embed.cc index 463148d..4734edb 100644 --- a/src/steg/embed.cc +++ b/src/steg/embed.cc @@ -82,14 +82,14 @@ embed_steg_config_t::embed_steg_config_t(config_t *cfg) for (vector<trace_t>::iterator p = traces.begin(); p != traces.end(); ++p) { int num_pkt; if (fscanf(trace_file, "%d", &num_pkt) < 1) - log_abort("couldn't read number of packets in trace %li", + log_abort("couldn't read number of packets in trace %ld", (long)(p - traces.begin())); p->pkt_sizes.resize(num_pkt); p->pkt_times.resize(num_pkt); for (int i = 0; i < num_pkt; i++) if (fscanf(trace_file, "%hd %d", &p->pkt_sizes[i], &p->pkt_times[i]) < 1) - log_abort("couldn't read trace entry %li/%d", + log_abort("couldn't read trace entry %ld/%d", (long)(p - traces.begin()), i); }

1 0

[stegotorus/master] Add support for daemonizing and writing a pid file.
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit 337fadeede2d4418ae569173cdf19ed2465444e3 Author: Zack Weinberg <zackw(a)cmu.edu> Date: Wed Jun 13 22:09:58 2012 -0400 Add support for daemonizing and writing a pid file. --- src/audit-globals.sh | 2 + src/main.cc | 53 +++++++++++++++++++----- src/subprocess-unix.cc | 105 ++++++++++++++++++++++++++++++++++++++++++++++++ src/subprocess.h | 39 ++++++++++++++++++ 4 files changed, 188 insertions(+), 11 deletions(-) diff --git a/src/audit-globals.sh b/src/audit-globals.sh index 27cab3a..7c28f21 100644 --- a/src/audit-globals.sh +++ b/src/audit-globals.sh @@ -39,7 +39,9 @@ sed ' /^crypt crypto_initialized$/d /^crypt crypto_errs_initialized$/d /^main allow_kq$/d + /^main daemon_mode$/d /^main handle_signal_cb(int, short, void\*)::got_sigint$/d + /^main pidfile_name$/d /^main registration_helper$/d /^main the_event_base$/d /^network listeners$/d diff --git a/src/main.cc b/src/main.cc index dd69e68..42687e1 100644 --- a/src/main.cc +++ b/src/main.cc @@ -37,6 +37,8 @@ using std::string; static struct event_base *the_event_base; static bool allow_kq = false; +static bool daemon_mode = false; +static string pidfile_name; static string registration_helper; /** @@ -234,7 +236,11 @@ usage(void) "--log-min-severity=warn|info|debug ~ set minimum logging severity\n" "--no-log ~ disable logging\n" "--timestamp-logs ~ add timestamps to all log messages\n" - "--allow-kqueue ~ allow use of kqueue(2) (may be buggy)\n"); + "--allow-kqueue ~ allow use of kqueue(2) (may be buggy)\n" + "--registration-helper=<helper> ~ use <helper> to register with " + "a relay database\n" + "--pid-file=<file> ~ write process ID to <file> after startup\n" + "--daemon ~ run as a daemon"); exit(1); } @@ -256,7 +262,8 @@ handle_generic_args(const char *const *argv) bool logsev_set = false; bool allow_kq_set = false; bool timestamps_set = false; - bool registration_helper_set=false; + bool registration_helper_set = false; + bool pidfile_set = false; int i = 1; while (argv[i] && @@ -278,21 +285,19 @@ handle_generic_args(const char *const *argv) fprintf(stderr, "you've already set a min. log severity!\n"); exit(1); } - if (log_set_min_severity((char *)argv[i]+19) < 0) { - fprintf(stderr, "error at setting logging severity"); + if (log_set_min_severity(argv[i]+19) < 0) { + fprintf(stderr, "invalid min. log severity '%s'", argv[i]+19); exit(1); } logsev_set = true; } else if (!strcmp(argv[i], "--no-log")) { - if (logsev_set) { - fprintf(stderr, "you've already set a min. log severity!\n"); + if (logsev_set || logmethod_set) { + fprintf(stderr, "can't ask for both some logs and no logs!\n"); exit(1); } - if (log_set_method(LOG_METHOD_NULL, NULL) < 0) { - fprintf(stderr, "error at setting logging severity.\n"); - exit(1); - } - logsev_set = true; + log_set_method(LOG_METHOD_NULL, NULL); + logsev_set = true; + logmethod_set = true; } else if (!strcmp(argv[i], "--timestamp-logs")) { if (timestamps_set) { fprintf(stderr, "you've already asked for timestamps!\n"); @@ -314,6 +319,19 @@ handle_generic_args(const char *const *argv) } registration_helper = string(argv[i]+22); registration_helper_set = true; + } else if (!strncmp(argv[i], "--pid-file=", 11)) { + if (pidfile_set) { + fprintf(stderr, "you've already set a pid file!\n"); + exit(1); + } + pidfile_name = string(argv[i]+11); + pidfile_set = true; + } else if (!strcmp(argv[i], "--daemon")) { + if (daemon_mode) { + fprintf(stderr, "you've already requested daemon mode!\n"); + exit(1); + } + daemon_mode = true; } else { fprintf(stderr, "unrecognizable argument '%s'\n", argv[i]); exit(1); @@ -321,6 +339,12 @@ handle_generic_args(const char *const *argv) i++; } + /* Cross-option consistency checks. */ + if (daemon_mode && !logmethod_set) { + log_warn("cannot log to stderr in daemon mode"); + log_set_method(LOG_METHOD_NULL, NULL); + } + return i; } @@ -380,6 +404,13 @@ main(int, const char *const *argv) log_assert(configs.size() > 0); /* Configurations have been established; proceed with initialization. */ + if (daemon_mode) + daemonize(); + + pidfile pf(pidfile_name); + if (!pf) + log_warn("failed to create pid-file '%s': %s", pf.pathname().c_str(), + pf.errmsg()); init_crypto(); diff --git a/src/subprocess-unix.cc b/src/subprocess-unix.cc index 7e075d9..573b167 100644 --- a/src/subprocess-unix.cc +++ b/src/subprocess-unix.cc @@ -13,6 +13,7 @@ #include "subprocess.h" #include <map> +#include <sstream> #include <sys/stat.h> #include <dirent.h> @@ -465,3 +466,107 @@ get_environ(const char *exclude) return result; } + +void +daemonize() +{ + if (getppid() == 1) // already a daemon + return; + + // Close standard I/O file descriptors and reopen them on /dev/null. + // We do this before forking (a) to avoid any possibility of + // double-flushed stdio buffers, and (b) so we can exit + // unsuccessfully in the unlikely event of a failure. + fflush(NULL); // flush all open stdio buffers + + close(0); + if (open("/dev/null", O_RDONLY) != 0) + log_abort("/dev/null: %s", strerror(errno)); + + close(1); + if (open("/dev/null", O_WRONLY) != 1) + log_abort("/dev/null: %s", strerror(errno)); + + // N.B. log_abort might be writing somewhere other than stderr. + // In fact, we rather hope it is, 'cos otherwise all logs from + // the child are gonna go to the bit bucket. + close(2); + if (open("/dev/null", O_WRONLY) != 2) + log_abort("/dev/null: %s", strerror(errno)); + + pid_t pid = fork(); + if (pid < 0) + log_abort("fork failed: %s", strerror(errno)); + + if (pid > 0) // Parent + // The use of _exit instead of exit here is deliberate. + // It's the process that carries on from this function that + // should do atexit cleanups (eventually). + _exit(0); + + // Become a session leader, and then fork one more time and exit in + // the parent. (This puts the process that will actually be the + // daemon in an orphaned process group. On some systems, this is + // necessary to ensure that the daemon can never acquire a controlling + // terminal again. XXX On some systems will the grandchild receive + // an unwanted, probably-fatal SIGHUP when its session leader exits?) + setsid(); + if (fork()) + _exit(0); + + // For the moment we do not chdir anywhere, because the HTTP steg expects + // to find its traces relative to the cwd. FIXME. +} + +pidfile::pidfile(std::string const& p) + : path(p), errcode(0) +{ + if (path.empty()) + return; + + std::ostringstream ss; + ss << getpid() << '\n'; + const char *b = ss.str().c_str(); + size_t n = ss.str().size(); + + int f = open(path.c_str(), O_WRONLY|O_CREAT|O_EXCL, 0666); + if (f == -1) { + errcode = errno; + return; + } + + do { + ssize_t r = write(f, b, n); + if (r < 0) { + errcode = errno; + close(f); + remove(path.c_str()); + return; + } + n -= r; + b += r; + } while (n > 0); + + // Sadly, close() can fail, and in this case it actually matters. + if (close(f)) { + errcode = errno; + remove(path.c_str()); + } +} + +pidfile::~pidfile() +{ + if (!errcode && !path.empty()) + remove(path.c_str()); +} + +pidfile::operator bool() const +{ + return !errcode; +} + +const char * +pidfile::errmsg() const +{ + return errcode ? strerror(errcode) : 0; +} diff --git a/src/subprocess.h b/src/subprocess.h index 95fe848..73eeece 100644 --- a/src/subprocess.h +++ b/src/subprocess.h @@ -65,4 +65,43 @@ struct subprocess // begins with those characters will be excluded from the result. extern std::vector<std::string> get_environ(const char *exclude = 0); +// These are in here because they involve process management 'under the hood', +// and because (like other process management) their Unix and Windows +// implementations have to be radically different. + +// Turn into a daemon; detach from the parent process and any +// controlling terminal. Closes standard I/O streams and reopens them +// to /dev/null. If this returns, it succeeded. +extern void daemonize(); + +// Instantiating this class causes a file to be created at the specified +// pathname, which contains the decimal process ID of the current process. +// On destruction, the file is deleted. +// +// If you're going to call daemonize(), you need to do it _before_ creating +// one of these, because daemonize() changes the process ID. + +class pidfile +{ +public: + pidfile(const std::string& p); + ~pidfile(); + + const std::string& pathname() const { return path; } + + // True if pid-file creation succeeded. + operator bool() const; + + // If pid-file creation did *not* succeed, returns the underlying system + // error message. You should combine that with the pathname and some + // text to the effect that this is a process ID file for the actual error + // message printed to the user. + // If pid-file creation *did* succeed, returns NULL. + const char *errmsg() const; + +private: + std::string path; + int errcode; +}; + #endif

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[stegotorus/master] Fix that race condition in connection setup again. This time for sure!
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit e0ade2128ee7b21cede4b2477b5f00f0f2f8d51c Author: Zack Weinberg <zackw(a)cmu.edu> Date: Wed Jun 13 15:06:13 2012 -0400 Fix that race condition in connection setup again. This time for sure! --- src/protocol/chop.cc | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index 67ed2b3..20ba563 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -903,11 +903,22 @@ chop_circuit_t::pick_connection(size_t desired, size_t *blocksize) for (unordered_set<chop_conn_t *>::iterator i = downstreams.begin(); i != downstreams.end(); i++) { chop_conn_t *conn = *i; + + // We cannot transmit on a connection whose steganography module has + // not yet been instantiated. (This only ever happens server-side.) if (!conn->steg) { log_debug(conn, "offers 0 bytes (no steg)"); continue; } + // We must not transmit on a connection that has not completed its + // TCP handshake. (This only ever happens client-side. If we try + // it anyway, the transmission gets silently dropped on the floor.) + if (!conn->connected) { + log_debug(conn, "offers 0 bytes (not connected)"); + continue; + } + size_t shake = conn->sent_handshake ? 0 : HANDSHAKE_LEN; size_t room = conn->steg->transmit_room(desired + shake, lo + shake, MAX_BLOCK_SIZE + shake);

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[stegotorus/master] Fix another subtle circuit-teardown bug.
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit 77316e9364db0d629354148145f2575fbd835260 Author: Zack Weinberg <zackw(a)cmu.edu> Date: Fri Jun 15 13:37:28 2012 -0700 Fix another subtle circuit-teardown bug. --- src/connections.cc | 5 +++-- src/connections.h | 7 +++++-- src/network.cc | 15 +++++++++------ src/protocol/chop.cc | 7 +++++-- src/protocol/null.cc | 1 + 5 files changed, 23 insertions(+), 12 deletions(-) diff --git a/src/connections.cc b/src/connections.cc index 4f95d12..f252b23 100644 --- a/src/connections.cc +++ b/src/connections.cc @@ -247,6 +247,7 @@ circuit_send(circuit_t *ckt) void circuit_send_eof(circuit_t *ckt) { + ckt->pending_eof_send = true; if (ckt->socks_state) { log_debug(ckt, "EOF during SOCKS phase"); delete ckt; @@ -271,11 +272,11 @@ circuit_recv_eof(circuit_t *ckt) shutdown(bufferevent_getfd(ckt->up_buffer), SHUT_WR); } else { log_debug(ckt, "holding EOF till connection"); - ckt->pending_eof = 1; + ckt->pending_eof_recv = true; } } else { log_debug(ckt, "no buffer, holding EOF till connection"); - ckt->pending_eof = 1; + ckt->pending_eof_recv = true; } } diff --git a/src/connections.h b/src/connections.h index 64a4252..76c5f56 100644 --- a/src/connections.h +++ b/src/connections.h @@ -121,9 +121,12 @@ struct circuit_t { bool connected : 1; bool flushing : 1; - bool pending_eof : 1; + bool pending_eof_recv : 1; + bool pending_eof_send : 1; - circuit_t() : connected(false), flushing(false), pending_eof(false) {} + circuit_t() + : connected(false), flushing(false), + pending_eof_recv(false), pending_eof_send(false) {} virtual ~circuit_t(); /** Return the configuration that this circuit belongs to. */ diff --git a/src/network.cc b/src/network.cc index b5f6d4b..25a05e4 100644 --- a/src/network.cc +++ b/src/network.cc @@ -346,9 +346,11 @@ upstream_event_cb(struct bufferevent *bev, short what, void *arg) /* Upstream is done sending us data. */ circuit_send_eof(ckt); if (bufferevent_get_enabled(bev) || - evbuffer_get_length(bufferevent_get_input(bev)) > 0) { + evbuffer_get_length(bufferevent_get_input(bev)) > 0 || + ckt->pending_eof_send) { log_debug(ckt, "acknowledging EOF upstream"); shutdown(bufferevent_getfd(bev), SHUT_RD); + bufferevent_disable(bev, EV_READ); } else { delete ckt; } @@ -428,11 +430,12 @@ upstream_flush_cb(struct bufferevent *bev, void *arg) if (remain == 0 && ckt->flushing && ckt->connected && (!ckt->flush_timer || !evtimer_pending(ckt->flush_timer, NULL))) { - bufferevent_disable(bev, EV_WRITE); if (bufferevent_get_enabled(bev) || - evbuffer_get_length(bufferevent_get_input(bev)) > 0) { + evbuffer_get_length(bufferevent_get_input(bev)) > 0 || + ckt->pending_eof_send) { log_debug(ckt, "sending EOF upstream"); shutdown(bufferevent_getfd(bev), SHUT_WR); + bufferevent_disable(bev, EV_WRITE); } else { delete ckt; } @@ -485,7 +488,7 @@ upstream_connect_cb(struct bufferevent *bev, short what, void *arg) upstream_event_cb, ckt); bufferevent_enable(ckt->up_buffer, EV_READ|EV_WRITE); ckt->connected = 1; - if (ckt->pending_eof) { + if (ckt->pending_eof_recv) { /* Try again to process the EOF. */ circuit_recv_eof(ckt); } @@ -530,7 +533,7 @@ downstream_connect_cb(struct bufferevent *bev, short what, void *arg) return; } - if (ckt->pending_eof) { + if (ckt->pending_eof_recv) { /* Try again to process the EOF. */ circuit_recv_eof(ckt); } @@ -624,7 +627,7 @@ downstream_socks_connect_cb(struct bufferevent *bev, short what, void *arg) connection. */ upstream_read_cb(ckt->up_buffer, ckt); - if (ckt->pending_eof) { + if (ckt->pending_eof_recv) { /* Try again to process the EOF. */ circuit_recv_eof(ckt); } diff --git a/src/protocol/chop.cc b/src/protocol/chop.cc index a30dd94..65ee661 100644 --- a/src/protocol/chop.cc +++ b/src/protocol/chop.cc @@ -569,6 +569,7 @@ chop_circuit_t::~chop_circuit_t() sent_fin ? '+' : '-', received_fin ? '+' : '-', upstream_eof ? '+' : '-', (unsigned long)downstreams.size()); + *(volatile char *)0 = 0; } for (unordered_set<chop_conn_t *>::iterator i = downstreams.begin(); @@ -870,9 +871,11 @@ chop_circuit_t::send_targeted(chop_conn_t *conn, size_t d, size_t p, opcode_t f, evbuffer_drain(payload, d); send_seq++; - if (f == op_FIN) + if (f == op_FIN) { sent_fin = true; - if ((f == op_DAT || f == op_FIN) && d > 0) + pending_eof_send = false; + } + if ((f == op_DAT && d > 0) || f == op_FIN) // We are making forward progress if we are _either_ sending or // receiving data. dead_cycles = 0; diff --git a/src/protocol/null.cc b/src/protocol/null.cc index ca6cc74..dab712a 100644 --- a/src/protocol/null.cc +++ b/src/protocol/null.cc @@ -208,6 +208,7 @@ null_circuit_t::send_eof() { if (this->downstream) conn_send_eof(this->downstream); + this->pending_eof_send = false; return 0; }

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[stegotorus/master] Remove an obsolete comment.
by zwol＠torproject.org 20 Jul '12

20 Jul '12

commit beb0f627a1cc79bf074e05334b411c5c09097ea6 Author: Zack Weinberg <zackw(a)cmu.edu> Date: Fri Jun 15 13:39:29 2012 -0700 Remove an obsolete comment. --- src/test/itestlib.py | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/src/test/itestlib.py b/src/test/itestlib.py index 90b1906..7378c3d 100644 --- a/src/test/itestlib.py +++ b/src/test/itestlib.py @@ -45,12 +45,9 @@ def diff(label, expected, received): # /dev/tty with useless diagnostics" (the documentation SAYS # they go to stderr, but they don't). -# there is an as-yet-not-pinned-down bug, probably in libevent, that -# causes deadlocks on OSX when kqueue is allowed. stegotorus_env = {} stegotorus_env.update(os.environ) stegotorus_env['MALLOC_CHECK_'] = '2' -stegotorus_env['EVENT_NOKQUEUE'] = '1' # check for a grinder if 'GRINDER' in stegotorus_env:

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