commit 7539220546986e3a5e35498ba6980f429da1427f Author: Vinod Yegneswaran vinod@safdef.isc.org Date: Tue Feb 14 15:30:47 2012 -0800
adding changes to Makefiles.am and http.cc --- Makefile.am | 3 + src/steg/http.cc | 245 ++++++++++++++++++++++++++++------------------------- 2 files changed, 132 insertions(+), 116 deletions(-)
diff --git a/Makefile.am b/Makefile.am index 9affaed..d81d072 100644 --- a/Makefile.am +++ b/Makefile.am @@ -19,6 +19,9 @@ PROTOCOLS = \ src/protocol/null.cc
STEGANOGRAPHERS = \ + src/steg/b64cookies.cc \ + src/steg/b64encode.cc \ + src/steg/b64decode.cc \ src/steg/cookies.cc \ src/steg/crc32.cc \ src/steg/embed.cc \ diff --git a/src/steg/http.cc b/src/steg/http.cc index 3402ba7..3251995 100644 --- a/src/steg/http.cc +++ b/src/steg/http.cc @@ -40,6 +40,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "swfSteg.h" #include "pdfSteg.h" #include "jsSteg.h" +#include "b64cookies.h"
#include <event2/buffer.h> #include <stdio.h> @@ -254,116 +255,135 @@ http_client_cookie_transmit (http *s, struct evbuffer *source, conn_t *conn) { /* On the client side, we have to embed the data in a GET query somehow; the only plausible places to put it are the URL and cookies. This presently uses the URL. And it can't be binary. */ - // struct evbuffer *scratch; - struct evbuffer_iovec *iv; - int i, nv; - struct evbuffer *dest = conn_get_outbound(conn); - size_t sbuflen = evbuffer_get_length(source); - char buf[10000]; - unsigned char data[(int) sbuflen*2]; - // unsigned char outbuf[MAX_COOKIE_SIZE];
- unsigned char outbuf[(int) sbuflen*8]; - int datalen; - - - // size_t sofar = 0; - size_t cookie_len; - - - /* Convert all the data in 'source' to hexadecimal and write it to - 'scratch'. Data is padded to a multiple of four characters with - equals signs. */
+ struct evbuffer *dest = conn_get_outbound(conn); + size_t sbuflen = evbuffer_get_length(source); + int bufsize = 10000; + char* buf = (char*) xmalloc(bufsize);
- unsigned int len = 0; - unsigned int cnt = 0; + char* data; + char* data2 = (char*) xmalloc (sbuflen*4); + char* cookiebuf = (char*) xmalloc (sbuflen*8); + int payload_len = 0; + int cnt = 0; + int cookie_len = 0; + int rval; + int len = 0; + base64::encoder E;
- datalen = 0; - cookie_len = 4 * sbuflen + rand() % 4; + data = (char*) evbuffer_pullup(source, sbuflen);
+ if (data == NULL) { + log_debug("evbuffer_pullup failed"); + goto err; + }
- nv = evbuffer_peek(source, sbuflen, NULL, NULL, 0); - iv = (evbuffer_iovec*)xzalloc(sizeof(struct evbuffer_iovec) * nv);
- if (evbuffer_peek(source, sbuflen, NULL, iv, nv) != nv) { - free(iv); - return -1; - }
// retry up to 10 times - while (!len) { - len = find_client_payload(buf, sizeof(buf), TYPE_HTTP_REQUEST); - if (cnt++ == 10) return -1; + while (!payload_len) { + payload_len = find_client_payload(buf, bufsize, TYPE_HTTP_REQUEST); + if (cnt++ == 10) { + goto err; + } } - + buf[payload_len] = 0;
if (has_peer_name == 0 && lookup_peer_name_from_ip((char*) conn->peername, peername)) has_peer_name = 1;
- // if (find_uri_type(buf) != HTTP_CONTENT_SWF) { - // fprintf(stderr, "%s\n", buf); - // exit(-1); - // }
+ bzero(data2, sbuflen*4); + E.encode((char*) data, sbuflen, (char*) data2); + E.encode_end(data2+strlen((char*) data2));
+ len = (int) strlen(data2) - 1; + // remove trailing newline + data2[len] = 0; + + // substitute / with _, + with ., = with - that maybe inserted anywhere in the middle + sanitize_b64(data2, len);
- cnt = 0; + + cookie_len = gen_b64_cookie_field(cookiebuf, data2, len); + cookiebuf[cookie_len] = 0;
- for (i = 0; i < nv; i++) { - const unsigned char *p = (const unsigned char *)iv[i].iov_base; - const unsigned char *limit = p + iv[i].iov_len; - char c; - while (p < limit && cnt < sbuflen) { - c = *p++; - data[datalen] = "0123456789abcdef"[(c & 0xF0) >> 4]; - data[datalen+1] = "0123456789abcdef"[(c & 0x0F) >> 0]; - datalen += 2; - cnt++; - } + + + if (cookie_len < 0) { + log_debug("cookie generation failed\n"); + return -1; } +
- free(iv); + // add uri field + rval = evbuffer_add(dest, buf, strstr(buf, "\r\n") - buf + 2); + if (rval) { + log_warn("error adding uri field\n"); + goto err; + }
- if (cookie_len < 4) cookie_len = 4; + rval = evbuffer_add(dest, "Host: ", 6); + if (rval) { + log_warn("error adding host field\n"); + goto err; + }
- datalen = gen_cookie_field(outbuf, cookie_len, data, datalen); - log_debug("CLIENT: sending cookie of length = %d %d\n", datalen, (int) cookie_len); - // fprintf(stderr, "CLIENT: sending cookie of length = %d %d\n", datalen, (int) cookie_len); + rval = evbuffer_add(dest, peername, strlen(peername)); + if (rval) { + log_warn("error adding peername field\n"); + goto err; + }
- if (datalen < 0) { - log_debug("cookie generation failed\n"); - return -1; + + rval = evbuffer_add(dest, strstr(buf, "\r\n"), payload_len - (unsigned int) (strstr(buf, "\r\n") - buf)); + if (rval) { + log_warn("error adding HTTP fields\n"); + goto err; }
+ rval = evbuffer_add(dest, "Cookie: ", 8); + if (rval) { + log_warn("error adding cookie fields\n"); + goto err; + } + rval = evbuffer_add(dest, cookiebuf, cookie_len);
- if (evbuffer_add(dest, buf, strstr(buf, "\r\n") - buf + 2) || // add uri field - evbuffer_add(dest, "Host: ", 6) || - evbuffer_add(dest, peername, strlen(peername)) || - evbuffer_add(dest, strstr(buf, "\r\n"), len - (unsigned int) (strstr(buf, "\r\n") - buf)) || // add everything but first line - evbuffer_add(dest, "Cookie: ", 8) || - evbuffer_add(dest, outbuf, cookie_len) || - evbuffer_add(dest, "\r\n\r\n", 4)) { - log_debug("error ***********************"); - return -1; - } + if (rval) { + log_warn("error adding cookie buf\n"); + goto err; + }
- // debug - // log_warn("CLIENT HTTP request header:"); - // buf_dump((unsigned char*)buf, len, stderr);
- // sofar += datalen/2; - evbuffer_drain(source, datalen/2); + rval = evbuffer_add(dest, "\r\n\r\n", 4); + + if (rval) { + log_warn("error adding terminators \n"); + goto err; + }
- log_debug("CLIENT TRANSMITTED payload %d\n", (int) sbuflen); +
+ evbuffer_drain(source, sbuflen); + log_debug("CLIENT TRANSMITTED payload %d\n", (int) sbuflen); conn_cease_transmission(conn);
- s->type = find_uri_type(buf, sizeof(buf)); + s->type = find_uri_type(buf, bufsize); s->have_transmitted = true; + + + free(buf); + free(data2); return 0; + +err: + free(buf); + free(data2); + return -1; + }
@@ -547,11 +567,13 @@ http::transmit(struct evbuffer *source, conn_t *conn)
if (is_clientside) { /* On the client side, we have to embed the data in a GET query somehow; - the only plausible places to put it are the URL and cookies. This - presently uses the URL. And it can't be binary. */ + the only plausible places to put it are the URL and cookies. */
- if (evbuffer_get_length(source) < 72) - return http_client_uri_transmit(this, source, conn); //@@ + /* if (evbuffer_get_length(source) < 72) + return http_client_uri_transmit(this, source, conn); + */ + + //@@ return http_client_cookie_transmit(this, source, conn); //@@ } else { @@ -588,15 +610,16 @@ http::transmit(struct evbuffer *source, conn_t *conn) int http_server_receive(http *s, conn_t *conn, struct evbuffer *dest, struct evbuffer* source) {
- int cnt = 0; - unsigned char* data; + char* data; int type;
do { struct evbuffer_ptr s2 = evbuffer_search(source, "\r\n\r\n", sizeof ("\r\n\r\n") -1 , NULL); - unsigned char *p; - unsigned char c, h, secondhalf; + char *p; + char *pend; + char outbuf[MAX_COOKIE_SIZE]; + char outbuf2[MAX_COOKIE_SIZE]; int sofar = 0; int cookie_mode = 0;
@@ -609,7 +632,7 @@ http_server_receive(http *s, conn_t *conn, struct evbuffer *dest, struct evbuffe
log_debug("SERVER received request header of length %d", (int)s2.pos);
- data = evbuffer_pullup(source, s2.pos+4); + data = (char*) evbuffer_pullup(source, s2.pos+4);
if (data == NULL) { log_debug("SERVER evbuffer_pullup fails"); @@ -622,54 +645,45 @@ http_server_receive(http *s, conn_t *conn, struct evbuffer *dest, struct evbuffe type = find_uri_type((char *)data, s2.pos+4);
if (strstr((char*) data, "Cookie") != NULL) { - p = (unsigned char*) strstr((char*) data, "Cookie:") + sizeof "Cookie: "-1; + p = strstr((char*) data, "Cookie:") + sizeof "Cookie: "-1; cookie_mode = 1; } else p = data + sizeof "GET /" -1;
+ pend = strstr(p, "\r\n");
- secondhalf = 0; - c = 0; + if (pend == NULL || (pend - p > MAX_COOKIE_SIZE)) { + fprintf(stderr, "incorrect cookie recovery \n"); + exit(-1); + + }
- while (strncmp((char*) p, "\r\n", 2) != 0 && (cookie_mode != 0 || p[0] != '.') && sofar < MAX_COOKIE_SIZE) { - if (!secondhalf) - c = 0; - if ('0' <= *p && *p <= '9') - h = *p - '0'; - else if ('a' <= *p && *p <= 'f') - h = *p - 'a' + 10; - else { - p++; - continue; - }
- c = (c << 4) + h; - if (secondhalf) { - outbuf[sofar++] = c; - cnt++; - } - secondhalf = !secondhalf; - p++; - } + bzero(outbuf, sizeof(outbuf)); + int cookielen = unwrap_b64_cookie((char*) p, (char*) outbuf, pend - p);
- if (sofar >= MAX_COOKIE_SIZE) { - fprintf(stderr, "cookie buffer overflow\n"); - exit(-1); - } + desanitize_b64(outbuf, cookielen); + outbuf[cookielen] = '\n'; + bzero(outbuf2, sizeof(outbuf2));
- outbuf[sofar] = 0; + base64::decoder D; + sofar = D.decode(outbuf, cookielen+1, outbuf2);
- if (secondhalf) { - fprintf(stderr, "incorrect cookie or uri recovery \n"); - exit(-1); - }
+ if (sofar <= 0) + log_warn("decode failed\n"); + + + if (sofar >= MAX_COOKIE_SIZE) { + log_warn("cookie buffer overflow????\n"); + exit(-1); + }
- if (evbuffer_add(dest, outbuf, sofar)) { + if (evbuffer_add(dest, outbuf2, sofar)) { log_debug("Failed to transfer buffer"); return RECV_BAD; } @@ -679,7 +693,6 @@ http_server_receive(http *s, conn_t *conn, struct evbuffer *dest, struct evbuffe
s->have_received = 1; s->type = type; - // fprintf(stderr, "SERVER RECEIVED payload %d %d\n", cnt, type);
conn_transmit_soon(conn, 100); return RECV_GOOD;