diff options
Diffstat (limited to 'vnc.c')
| -rw-r--r-- | vnc.c | 404 |
1 files changed, 396 insertions, 8 deletions
@@ -32,14 +32,27 @@ #include "keymaps.c" #include "d3des.h" -// #define _VNC_DEBUG +#if CONFIG_VNC_TLS +#include <gnutls/gnutls.h> +#include <gnutls/x509.h> +#endif /* CONFIG_VNC_TLS */ -#ifdef _VNC_DEBUG +// #define _VNC_DEBUG 1 + +#if _VNC_DEBUG #define VNC_DEBUG(fmt, ...) do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0) + +#if CONFIG_VNC_TLS && _VNC_DEBUG >= 2 +/* Very verbose, so only enabled for _VNC_DEBUG >= 2 */ +static void vnc_debug_gnutls_log(int level, const char* str) { + VNC_DEBUG("%d %s", level, str); +} +#endif /* CONFIG_VNC_TLS && _VNC_DEBUG */ #else #define VNC_DEBUG(fmt, ...) do { } while (0) #endif + typedef struct Buffer { size_t capacity; @@ -77,6 +90,23 @@ enum { VNC_AUTH_VENCRYPT = 19 }; +#if CONFIG_VNC_TLS +enum { + VNC_WIREMODE_CLEAR, + VNC_WIREMODE_TLS, +}; + +enum { + VNC_AUTH_VENCRYPT_PLAIN = 256, + VNC_AUTH_VENCRYPT_TLSNONE = 257, + VNC_AUTH_VENCRYPT_TLSVNC = 258, + VNC_AUTH_VENCRYPT_TLSPLAIN = 259, + VNC_AUTH_VENCRYPT_X509NONE = 260, + VNC_AUTH_VENCRYPT_X509VNC = 261, + VNC_AUTH_VENCRYPT_X509PLAIN = 262, +}; +#endif /* CONFIG_VNC_TLS */ + struct VncState { QEMUTimer *timer; @@ -102,8 +132,16 @@ struct VncState char *display; char *password; int auth; +#if CONFIG_VNC_TLS + int subauth; +#endif char challenge[VNC_AUTH_CHALLENGE_SIZE]; +#if CONFIG_VNC_TLS + int wiremode; + gnutls_session_t tls_session; +#endif + Buffer output; Buffer input; kbd_layout_t *kbd_layout; @@ -579,12 +617,20 @@ static int vnc_client_io_error(VncState *vs, int ret, int last_errno) if (ret == -1 && (last_errno == EINTR || last_errno == EAGAIN)) return 0; + VNC_DEBUG("Closing down client sock %d %d\n", ret, ret < 0 ? last_errno : 0); qemu_set_fd_handler2(vs->csock, NULL, NULL, NULL, NULL); closesocket(vs->csock); vs->csock = -1; buffer_reset(&vs->input); buffer_reset(&vs->output); vs->need_update = 0; +#if CONFIG_VNC_TLS + if (vs->tls_session) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + } + vs->wiremode = VNC_WIREMODE_CLEAR; +#endif /* CONFIG_VNC_TLS */ return 0; } return ret; @@ -600,7 +646,19 @@ static void vnc_client_write(void *opaque) long ret; VncState *vs = opaque; - ret = send(vs->csock, vs->output.buffer, vs->output.offset, 0); +#if CONFIG_VNC_TLS + if (vs->tls_session) { + ret = gnutls_write(vs->tls_session, vs->output.buffer, vs->output.offset); + if (ret < 0) { + if (ret == GNUTLS_E_AGAIN) + errno = EAGAIN; + else + errno = EIO; + ret = -1; + } + } else +#endif /* CONFIG_VNC_TLS */ + ret = send(vs->csock, vs->output.buffer, vs->output.offset, 0); ret = vnc_client_io_error(vs, ret, socket_error()); if (!ret) return; @@ -626,7 +684,19 @@ static void vnc_client_read(void *opaque) buffer_reserve(&vs->input, 4096); - ret = recv(vs->csock, buffer_end(&vs->input), 4096, 0); +#if CONFIG_VNC_TLS + if (vs->tls_session) { + ret = gnutls_read(vs->tls_session, buffer_end(&vs->input), 4096); + if (ret < 0) { + if (ret == GNUTLS_E_AGAIN) + errno = EAGAIN; + else + errno = EIO; + ret = -1; + } + } else +#endif /* CONFIG_VNC_TLS */ + ret = recv(vs->csock, buffer_end(&vs->input), 4096, 0); ret = vnc_client_io_error(vs, ret, socket_error()); if (!ret) return; @@ -721,6 +791,41 @@ static uint32_t read_u32(uint8_t *data, size_t offset) (data[offset + 2] << 8) | data[offset + 3]); } +#if CONFIG_VNC_TLS +ssize_t vnc_tls_push(gnutls_transport_ptr_t transport, + const void *data, + size_t len) { + struct VncState *vs = (struct VncState *)transport; + int ret; + + retry: + ret = send(vs->csock, data, len, 0); + if (ret < 0) { + if (errno == EINTR) + goto retry; + return -1; + } + return ret; +} + + +ssize_t vnc_tls_pull(gnutls_transport_ptr_t transport, + void *data, + size_t len) { + struct VncState *vs = (struct VncState *)transport; + int ret; + + retry: + ret = recv(vs->csock, data, len, 0); + if (ret < 0) { + if (errno == EINTR) + goto retry; + return -1; + } + return ret; +} +#endif /* CONFIG_VNC_TLS */ + static void client_cut_text(VncState *vs, size_t len, char *text) { } @@ -1225,6 +1330,243 @@ static int start_auth_vnc(VncState *vs) return 0; } + +#if CONFIG_VNC_TLS +#define DH_BITS 1024 +static gnutls_dh_params_t dh_params; + +static int vnc_tls_initialize(void) +{ + static int tlsinitialized = 0; + + if (tlsinitialized) + return 1; + + if (gnutls_global_init () < 0) + return 0; + + /* XXX ought to re-generate diffie-hellmen params periodically */ + if (gnutls_dh_params_init (&dh_params) < 0) + return 0; + if (gnutls_dh_params_generate2 (dh_params, DH_BITS) < 0) + return 0; + +#if _VNC_DEBUG == 2 + gnutls_global_set_log_level(10); + gnutls_global_set_log_function(vnc_debug_gnutls_log); +#endif + + tlsinitialized = 1; + + return 1; +} + +static gnutls_anon_server_credentials vnc_tls_initialize_anon_cred(void) +{ + gnutls_anon_server_credentials anon_cred; + int ret; + + if ((ret = gnutls_anon_allocate_server_credentials(&anon_cred)) < 0) { + VNC_DEBUG("Cannot allocate credentials %s\n", gnutls_strerror(ret)); + return NULL; + } + + gnutls_anon_set_server_dh_params(anon_cred, dh_params); + + return anon_cred; +} + + +static int start_auth_vencrypt_subauth(VncState *vs) +{ + switch (vs->subauth) { + case VNC_AUTH_VENCRYPT_TLSNONE: + VNC_DEBUG("Accept TLS auth none\n"); + vnc_write_u32(vs, 0); /* Accept auth completion */ + vnc_read_when(vs, protocol_client_init, 1); + break; + + case VNC_AUTH_VENCRYPT_TLSVNC: + VNC_DEBUG("Start TLS auth VNC\n"); + return start_auth_vnc(vs); + + default: /* Should not be possible, but just in case */ + VNC_DEBUG("Reject auth %d\n", vs->auth); + vnc_write_u8(vs, 1); + if (vs->minor >= 8) { + static const char err[] = "Unsupported authentication type"; + vnc_write_u32(vs, sizeof(err)); + vnc_write(vs, err, sizeof(err)); + } + vnc_client_error(vs); + } + + return 0; +} + +static void vnc_handshake_io(void *opaque); + +static int vnc_continue_handshake(struct VncState *vs) { + int ret; + + if ((ret = gnutls_handshake(vs->tls_session)) < 0) { + if (!gnutls_error_is_fatal(ret)) { + VNC_DEBUG("Handshake interrupted (blocking)\n"); + if (!gnutls_record_get_direction(vs->tls_session)) + qemu_set_fd_handler(vs->csock, vnc_handshake_io, NULL, vs); + else + qemu_set_fd_handler(vs->csock, NULL, vnc_handshake_io, vs); + return 0; + } + VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret)); + vnc_client_error(vs); + return -1; + } + + VNC_DEBUG("Handshake done, switching to TLS data mode\n"); + vs->wiremode = VNC_WIREMODE_TLS; + qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs); + + return start_auth_vencrypt_subauth(vs); +} + +static void vnc_handshake_io(void *opaque) { + struct VncState *vs = (struct VncState *)opaque; + + VNC_DEBUG("Handshake IO continue\n"); + vnc_continue_handshake(vs); +} + +static int vnc_start_tls(struct VncState *vs) { + static const int cert_type_priority[] = { GNUTLS_CRT_X509, 0 }; + static const int protocol_priority[]= { GNUTLS_TLS1_1, GNUTLS_TLS1_0, GNUTLS_SSL3, 0 }; + static const int kx_anon[] = {GNUTLS_KX_ANON_DH, 0}; + gnutls_anon_server_credentials anon_cred = NULL; + + VNC_DEBUG("Do TLS setup\n"); + if (vnc_tls_initialize() < 0) { + VNC_DEBUG("Failed to init TLS\n"); + vnc_client_error(vs); + return -1; + } + if (vs->tls_session == NULL) { + if (gnutls_init(&vs->tls_session, GNUTLS_SERVER) < 0) { + vnc_client_error(vs); + return -1; + } + + if (gnutls_set_default_priority(vs->tls_session) < 0) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + vnc_client_error(vs); + return -1; + } + + if (gnutls_kx_set_priority(vs->tls_session, kx_anon) < 0) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + vnc_client_error(vs); + return -1; + } + + if (gnutls_certificate_type_set_priority(vs->tls_session, cert_type_priority) < 0) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + vnc_client_error(vs); + return -1; + } + + if (gnutls_protocol_set_priority(vs->tls_session, protocol_priority) < 0) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + vnc_client_error(vs); + return -1; + } + + anon_cred = vnc_tls_initialize_anon_cred(); + if (!anon_cred) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + vnc_client_error(vs); + return -1; + } + if (gnutls_credentials_set(vs->tls_session, GNUTLS_CRD_ANON, anon_cred) < 0) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + gnutls_anon_free_server_credentials(anon_cred); + vnc_client_error(vs); + return -1; + } + + gnutls_transport_set_ptr(vs->tls_session, (gnutls_transport_ptr_t)vs); + gnutls_transport_set_push_function(vs->tls_session, vnc_tls_push); + gnutls_transport_set_pull_function(vs->tls_session, vnc_tls_pull); + } + + VNC_DEBUG("Start TLS handshake process\n"); + return vnc_continue_handshake(vs); +} + +static int protocol_client_vencrypt_auth(VncState *vs, char *data, size_t len) +{ + int auth = read_u32(data, 0); + + if (auth != vs->subauth) { + VNC_DEBUG("Rejecting auth %d\n", auth); + vnc_write_u8(vs, 0); /* Reject auth */ + vnc_flush(vs); + vnc_client_error(vs); + } else { + VNC_DEBUG("Accepting auth %d, starting handshake\n", auth); + vnc_write_u8(vs, 1); /* Accept auth */ + vnc_flush(vs); + + if (vnc_start_tls(vs) < 0) { + VNC_DEBUG("Failed to complete TLS\n"); + return 0; + } + + if (vs->wiremode == VNC_WIREMODE_TLS) { + VNC_DEBUG("Starting VeNCrypt subauth\n"); + return start_auth_vencrypt_subauth(vs); + } else { + VNC_DEBUG("TLS handshake blocked\n"); + return 0; + } + } + return 0; +} + +static int protocol_client_vencrypt_init(VncState *vs, char *data, size_t len) +{ + if (data[0] != 0 || + data[1] != 2) { + VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]); + vnc_write_u8(vs, 1); /* Reject version */ + vnc_flush(vs); + vnc_client_error(vs); + } else { + VNC_DEBUG("Sending allowed auth %d\n", vs->subauth); + vnc_write_u8(vs, 0); /* Accept version */ + vnc_write_u8(vs, 1); /* Number of sub-auths */ + vnc_write_u32(vs, vs->subauth); /* The supported auth */ + vnc_flush(vs); + vnc_read_when(vs, protocol_client_vencrypt_auth, 4); + } + return 0; +} + +static int start_auth_vencrypt(VncState *vs) +{ + /* Send VeNCrypt version 0.2 */ + vnc_write_u8(vs, 0); + vnc_write_u8(vs, 2); + + vnc_read_when(vs, protocol_client_vencrypt_init, 2); + return 0; +} +#endif /* CONFIG_VNC_TLS */ + static int protocol_client_auth(VncState *vs, char *data, size_t len) { /* We only advertise 1 auth scheme at a time, so client @@ -1251,6 +1593,12 @@ static int protocol_client_auth(VncState *vs, char *data, size_t len) VNC_DEBUG("Start VNC auth\n"); return start_auth_vnc(vs); +#if CONFIG_VNC_TLS + case VNC_AUTH_VENCRYPT: + VNC_DEBUG("Accept VeNCrypt auth\n");; + return start_auth_vencrypt(vs); +#endif /* CONFIG_VNC_TLS */ + default: /* Should not be possible, but just in case */ VNC_DEBUG("Reject auth %d\n", vs->auth); vnc_write_u8(vs, 1); @@ -1331,6 +1679,7 @@ static void vnc_listen_read(void *opaque) vs->csock = accept(vs->lsock, (struct sockaddr *)&addr, &addrlen); if (vs->csock != -1) { + VNC_DEBUG("New client on socket %d\n", vs->csock); socket_set_nonblock(vs->csock); qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, opaque); vnc_write(vs, "RFB 003.008\n", 12); @@ -1404,8 +1753,18 @@ void vnc_display_close(DisplayState *ds) buffer_reset(&vs->input); buffer_reset(&vs->output); vs->need_update = 0; +#if CONFIG_VNC_TLS + if (vs->tls_session) { + gnutls_deinit(vs->tls_session); + vs->tls_session = NULL; + } + vs->wiremode = VNC_WIREMODE_CLEAR; +#endif /* CONFIG_VNC_TLS */ } vs->auth = VNC_AUTH_INVALID; +#if CONFIG_VNC_TLS + vs->subauth = VNC_AUTH_INVALID; +#endif } int vnc_display_password(DisplayState *ds, const char *password) @@ -1437,6 +1796,9 @@ int vnc_display_open(DisplayState *ds, const char *display) VncState *vs = ds ? (VncState *)ds->opaque : vnc_state; const char *options; int password = 0; +#if CONFIG_VNC_TLS + int tls = 0; +#endif vnc_display_close(ds); if (strcmp(display, "none") == 0) @@ -1450,14 +1812,40 @@ int vnc_display_open(DisplayState *ds, const char *display) options++; if (strncmp(options, "password", 8) == 0) password = 1; /* Require password auth */ +#if CONFIG_VNC_TLS + else if (strncmp(options, "tls", 3) == 0) + tls = 1; /* Require TLS */ +#endif } if (password) { - VNC_DEBUG("Initializing VNC server with password auth\n"); - vs->auth = VNC_AUTH_VNC; +#if CONFIG_VNC_TLS + if (tls) { + VNC_DEBUG("Initializing VNC server with TLS password auth\n"); + vs->auth = VNC_AUTH_VENCRYPT; + vs->subauth = VNC_AUTH_VENCRYPT_TLSVNC; + } else { +#endif + VNC_DEBUG("Initializing VNC server with password auth\n"); + vs->auth = VNC_AUTH_VNC; +#if CONFIG_VNC_TLS + vs->subauth = VNC_AUTH_INVALID; + } +#endif } else { - VNC_DEBUG("Initializing VNC server with no auth\n"); - vs->auth = VNC_AUTH_NONE; +#if CONFIG_VNC_TLS + if (tls) { + VNC_DEBUG("Initializing VNC server with TLS no auth\n"); + vs->auth = VNC_AUTH_VENCRYPT; + vs->subauth = VNC_AUTH_VENCRYPT_TLSNONE; + } else { +#endif + VNC_DEBUG("Initializing VNC server with no auth\n"); + vs->auth = VNC_AUTH_NONE; +#if CONFIG_VNC_TLS + vs->subauth = VNC_AUTH_INVALID; + } +#endif } #ifndef _WIN32 if (strstart(display, "unix:", &p)) { |