control/control: Refactor some error handling code

Split some protocol error handling out of
connection_control_process_inbuf().

This refactor reduces the size of a practracker exception.

Closes 31840.
This commit is contained in:
teor 2019-08-06 00:18:41 +10:00
parent e1429d9148
commit 3d17fafa04
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3 changed files with 59 additions and 25 deletions

3
changes/ticket31840 Normal file
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@ -0,0 +1,3 @@
o Code simplification and refactoring:
- Refactor connection_control_process_inbuf() to reduce the size of a
practracker exception. Closes ticket 31840.

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@ -186,7 +186,7 @@ problem file-size /src/feature/client/entrynodes.h 639
problem function-size /src/feature/client/transports.c:handle_proxy_line() 108 problem function-size /src/feature/client/transports.c:handle_proxy_line() 108
problem function-size /src/feature/client/transports.c:parse_method_line_helper() 110 problem function-size /src/feature/client/transports.c:parse_method_line_helper() 110
problem function-size /src/feature/client/transports.c:create_managed_proxy_environment() 109 problem function-size /src/feature/client/transports.c:create_managed_proxy_environment() 109
problem function-size /src/feature/control/control.c:connection_control_process_inbuf() 136 problem function-size /src/feature/control/control.c:connection_control_process_inbuf() 113
problem function-size /src/feature/control/control_auth.c:handle_control_authenticate() 186 problem function-size /src/feature/control/control_auth.c:handle_control_authenticate() 186
problem function-size /src/feature/control/control_cmd.c:handle_control_extendcircuit() 150 problem function-size /src/feature/control/control_cmd.c:handle_control_extendcircuit() 150
problem function-size /src/feature/control/control_cmd.c:handle_control_add_onion() 256 problem function-size /src/feature/control/control_cmd.c:handle_control_add_onion() 256

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@ -339,6 +339,60 @@ static const char CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG[] =
"</body>\n" "</body>\n"
"</html>\n"; "</html>\n";
/** Return an error on a control connection that tried to use the v0 protocol.
*/
static void
control_send_v0_reject(control_connection_t *conn)
{
size_t body_len;
char buf[128];
set_uint16(buf+2, htons(0x0000)); /* type == error */
set_uint16(buf+4, htons(0x0001)); /* code == internal error */
strlcpy(buf+6, "The v0 control protocol is not supported by Tor 0.1.2.17 "
"and later; upgrade your controller.",
sizeof(buf)-6);
body_len = 2+strlen(buf+6)+2; /* code, msg, nul. */
set_uint16(buf+0, htons(body_len));
connection_buf_add(buf, 4+body_len, TO_CONN(conn));
connection_mark_and_flush(TO_CONN(conn));
}
/** Return an error on a control connection that tried to use HTTP.
*/
static void
control_send_http_reject(control_connection_t *conn)
{
connection_write_str_to_buf(CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG, conn);
log_notice(LD_CONTROL, "Received HTTP request on ControlPort");
connection_mark_and_flush(TO_CONN(conn));
}
/** Check if a control connection has tried to use a known invalid protocol.
* If it has, then:
* - send a reject response,
* - log a notice-level message, and
* - return false. */
static bool
control_protocol_is_valid(control_connection_t *conn)
{
/* Detect v0 commands and send a "no more v0" message. */
if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
peek_connection_has_control0_command(TO_CONN(conn))) {
control_send_v0_reject(conn);
return 0;
}
/* If the user has the HTTP proxy port and the control port confused. */
if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
peek_connection_has_http_command(TO_CONN(conn))) {
control_send_http_reject(conn);
return 0;
}
return 1;
}
/** Called when data has arrived on a v1 control connection: Try to fetch /** Called when data has arrived on a v1 control connection: Try to fetch
* commands from conn->inbuf, and execute them. * commands from conn->inbuf, and execute them.
*/ */
@ -359,30 +413,7 @@ connection_control_process_inbuf(control_connection_t *conn)
conn->incoming_cmd_cur_len = 0; conn->incoming_cmd_cur_len = 0;
} }
if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH && if (!control_protocol_is_valid(conn)) {
peek_connection_has_control0_command(TO_CONN(conn))) {
/* Detect v0 commands and send a "no more v0" message. */
size_t body_len;
char buf[128];
set_uint16(buf+2, htons(0x0000)); /* type == error */
set_uint16(buf+4, htons(0x0001)); /* code == internal error */
strlcpy(buf+6, "The v0 control protocol is not supported by Tor 0.1.2.17 "
"and later; upgrade your controller.",
sizeof(buf)-6);
body_len = 2+strlen(buf+6)+2; /* code, msg, nul. */
set_uint16(buf+0, htons(body_len));
connection_buf_add(buf, 4+body_len, TO_CONN(conn));
connection_mark_and_flush(TO_CONN(conn));
return 0;
}
/* If the user has the HTTP proxy port and the control port confused. */
if (conn->base_.state == CONTROL_CONN_STATE_NEEDAUTH &&
peek_connection_has_http_command(TO_CONN(conn))) {
connection_write_str_to_buf(CONTROLPORT_IS_NOT_AN_HTTP_PROXY_MSG, conn);
log_notice(LD_CONTROL, "Received HTTP request on ControlPort");
connection_mark_and_flush(TO_CONN(conn));
return 0; return 0;
} }