#include "para.h"
#include "error.h"
#include "crypt.h"
+#include "sideband.h"
#include "command.h"
#include "server.cmdline.h"
#include "string.h"
return 1;
}
+/**
+ * Send a sideband packet through a blocking file descriptor.
+ *
+ * \param scc fd and crypto keys.
+ * \param buf The buffer to send.
+ * \param numbytes The size of \a buf.
+ * \param band The sideband designator of this packet.
+ * \param dont_free If true, never deallocate \a buf.
+ *
+ * The nonblock flag must be disabled for the file descriptor given by \a scc.
+ *
+ * Stream cipher encryption is automatically activated if neccessary via the
+ * sideband transformation, depending on the value of \a band.
+ *
+ * \return Standard.
+ *
+ * \sa \ref send_sb_va().
+ */
+int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
+ int band, bool dont_free)
+{
+ int ret;
+ struct sb_context *sbc;
+ struct iovec iov[2];
+ struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
+ sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
+
+ sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
+ do {
+ ret = sb_get_send_buffers(sbc, iov);
+ ret = xwritev(scc->fd, iov, ret);
+ if (ret < 0)
+ goto fail;
+ } while (sb_sent(sbc, ret) == false);
+ return 1;
+fail:
+ sb_free(sbc);
+ return ret;
+}
+
+/**
+ * Create a variable sized buffer and send it as a sideband packet.
+ *
+ * \param scc Passed to \ref send_sb.
+ * \param band See \ref send_sb.
+ * \param fmt The format string.
+ *
+ * \return The return value of the underlying call to \ref send_sb.
+ */
+__printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
+ const char *fmt, ...)
+{
+ va_list ap;
+ char *msg;
+ int ret;
+
+ va_start(ap, fmt);
+ ret = xvasprintf(&msg, fmt, ap);
+ va_end(ap);
+ return send_sb(scc, msg, ret, band, false);
+}
+
+/**
+ * Send a sideband packet through a blocking file descriptor.
+ *
+ * \param scc fd and crypto keys.
+ * \param expected_band The expected band designator.
+ * \param max_size Passed to \ref sb_new_recv().
+ * \param result Body of the sideband packet is returned here.
+ *
+ * If \a expected_band is not \p SBD_ANY, the band designator of the received
+ * sideband packet is compared to \a expected_band and a mismatch is considered
+ * an error.
+ *
+ * \return Standard.
+ */
+int recv_sb(struct stream_cipher_context *scc,
+ enum sb_designator expected_band,
+ size_t max_size, struct iovec *result)
+{
+ int ret;
+ struct sb_context *sbc;
+ struct iovec iov;
+ struct sb_buffer sbb;
+ sb_transformation trafo;
+
+ trafo = expected_band != SBD_ANY && expected_band < SBD_PROCEED?
+ NULL : sc_trafo;
+ sbc = sb_new_recv(max_size, trafo, scc->recv);
+ for (;;) {
+ sb_get_recv_buffer(sbc, &iov);
+ ret = recv_bin_buffer(scc->fd, iov.iov_base, iov.iov_len);
+ if (ret == 0)
+ ret = -E_EOF;
+ if (ret < 0)
+ goto fail;
+ ret = sb_received(sbc, ret, &sbb);
+ if (ret < 0)
+ goto fail;
+ if (ret > 0)
+ break;
+ }
+ ret = -E_BAD_BAND;
+ if (expected_band != SBD_ANY && sbb.band != expected_band)
+ goto fail;
+ *result = sbb.iov;
+ return 1;
+fail:
+ sb_free(sbc);
+ return ret;
+}
+
int com_sender(struct command_context *cc)
{
int i, ret;
return ret;
}
+#define HANDSHAKE_BUFSIZE 4096
+
/**
* Perform user authentication and execute a command.
*
__noreturn void handle_connect(int fd, const char *peername)
{
int ret;
- char buf[4096];
unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
unsigned char challenge_hash[HASH_SIZE];
- char *p, *command = NULL;
+ char *p, *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
size_t numbytes;
struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
if (ret < 0)
goto net_err;
/* recv auth request line */
- ret = recv_buffer(fd, buf, sizeof(buf));
+ ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
if (ret < 0)
goto net_err;
ret = parse_auth_request(buf, ret, &cc->u, &cc->use_sideband);
}
PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
CHALLENGE_SIZE, numbytes);
- ret = write_all(fd, buf, numbytes);
- if (ret < 0)
- goto net_err;
- /* recv challenge response */
- ret = recv_bin_buffer(fd, buf, HASH_SIZE);
- if (ret < 0)
- goto net_err;
- numbytes = ret;
- PARA_DEBUG_LOG("received %d bytes challenge response\n", ret);
+ if (cc->use_sideband) {
+ struct iovec iov;
+ ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
+ buf = NULL;
+ if (ret < 0)
+ goto net_err;
+ ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
+ HANDSHAKE_BUFSIZE, &iov);
+ if (ret < 0)
+ goto net_err;
+ buf = iov.iov_base;
+ numbytes = iov.iov_len;
+ } else {
+ ret = write_all(fd, buf, numbytes);
+ if (ret < 0)
+ goto net_err;
+ /* recv challenge response */
+ ret = recv_bin_buffer(fd, buf, HASH_SIZE);
+ if (ret < 0)
+ goto net_err;
+ numbytes = ret;
+ }
+ PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
ret = -E_BAD_USER;
if (!cc->u)
goto net_err;
net_err:
PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
out:
+ free(buf);
free(command);
sc_free(cc->scc.recv);
sc_free(cc->scc.send);
projects / paraslash.git / blobdiff