89 lines
3.3 KiB
Diff
89 lines
3.3 KiB
Diff
From 336bd86d2ca4030b808d76e56a0387914982e289 Mon Sep 17 00:00:00 2001
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From: Will Cosgrove <will@panic.com>
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Date: Fri, 13 Sep 2019 09:45:34 -0700
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Subject: [PATCH] packet.c: improved parsing in packet_x11_open (#410)
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Use new API to parse data in packet_x11_open() for better bounds checking.
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---
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src/packet.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++--------------
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1 file changed, 49 insertions(+), 14 deletions(-)
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diff --git a/src/packet.c b/src/packet.c
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index c83a68d..9897f77 100644
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--- a/src/packet.c
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+++ b/src/packet.c
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@@ -295,21 +295,56 @@ packet_x11_open(LIBSSH2_SESSION * session, unsigned char *data,
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LIBSSH2_CHANNEL *channel = x11open_state->channel;
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int rc;
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- (void) datalen;
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-
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if(x11open_state->state == libssh2_NB_state_idle) {
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- unsigned char *s = data + (sizeof("x11") - 1) + 5;
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- x11open_state->sender_channel = _libssh2_ntohu32(s);
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- s += 4;
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- x11open_state->initial_window_size = _libssh2_ntohu32(s);
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- s += 4;
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- x11open_state->packet_size = _libssh2_ntohu32(s);
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- s += 4;
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- x11open_state->shost_len = _libssh2_ntohu32(s);
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- s += 4;
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- x11open_state->shost = s;
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- s += x11open_state->shost_len;
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- x11open_state->sport = _libssh2_ntohu32(s);
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+
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+ unsigned long offset = (sizeof("x11") - 1) + 5;
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+ size_t temp_len = 0;
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+ struct string_buf buf;
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+ buf.data = data;
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+ buf.dataptr = buf.data;
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+ buf.len = datalen;
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+
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+ if(datalen < offset) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected data length");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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+
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+ buf.dataptr += offset;
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+
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+ if(_libssh2_get_u32(&buf, &(x11open_state->sender_channel))) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected sender channel size");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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+ if(_libssh2_get_u32(&buf, &(x11open_state->initial_window_size))) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected window size");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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+ if(_libssh2_get_u32(&buf, &(x11open_state->packet_size))) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected window size");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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+ if(_libssh2_get_string(&buf, &(x11open_state->shost), &temp_len)) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected host size");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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+ x11open_state->shost_len = (uint32_t)temp_len;
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+
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+ if(_libssh2_get_u32(&buf, &(x11open_state->sport))) {
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+ _libssh2_error(session, LIBSSH2_ERROR_INVAL,
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+ "unexpected port size");
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+ failure_code = SSH_OPEN_CONNECT_FAILED;
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+ goto x11_exit;
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+ }
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_libssh2_debug(session, LIBSSH2_TRACE_CONN,
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"X11 Connection Received from %s:%ld on channel %lu",
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--
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1.8.3.1
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