ssl_pkt.h File Reference

#include "buffer.h"
#include "ssl_backend.h"
#include "ssl_common.h"

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Data Structures
struct	tls_auth_standalone
struct	tls_pre_decrypt_state
	struct that stores the temporary data for the tls lite decrypt functions More...

Macros
#define	P_KEY_ID_MASK   0x07
#define	P_OPCODE_SHIFT   3
#define	P_CONTROL_HARD_RESET_CLIENT_V1   1 /* initial key from client, forget previous state */
#define	P_CONTROL_HARD_RESET_SERVER_V1   2 /* initial key from server, forget previous state */
#define	P_CONTROL_SOFT_RESET_V1   3 /* new key, graceful transition from old to new key */
#define	P_CONTROL_V1   4 /* control channel packet (usually TLS ciphertext) */
#define	P_ACK_V1   5 /* acknowledgement for packets received */
#define	P_DATA_V1   6 /* data channel packet */
#define	P_DATA_V2   9 /* data channel packet with peer-id */
#define	P_CONTROL_HARD_RESET_CLIENT_V2   7 /* initial key from client, forget previous state */
#define	P_CONTROL_HARD_RESET_SERVER_V2   8 /* initial key from server, forget previous state */
#define	P_CONTROL_HARD_RESET_CLIENT_V3   10 /* initial key from client, forget previous state */
#define	P_CONTROL_WKC_V1   11
#define	P_FIRST_OPCODE   3
#define	P_LAST_OPCODE   11
#define	TLS_RELIABLE_N_SEND_BUFFERS   6 /* also window size for reliability layer */
#define	TLS_RELIABLE_N_REC_BUFFERS   12
#define	EARLY_NEG_MASK   0xff000000
#define	EARLY_NEG_START   0x0f000000
#define	TLV_TYPE_EARLY_NEG_FLAGS   0x0001
#define	EARLY_NEG_FLAG_RESEND_WKC   0x0001

Enumerations
enum	first_packet_verdict {   VERDICT_VALID_RESET_V2, VERDICT_VALID_RESET_V3, VERDICT_VALID_CONTROL_V1, VERDICT_VALID_ACK_V1,   VERDICT_VALID_WKC_V1, VERDICT_INVALID }

Functions
void	free_tls_pre_decrypt_state (struct tls_pre_decrypt_state *state)
enum first_packet_verdict	tls_pre_decrypt_lite (const struct tls_auth_standalone *tas, struct tls_pre_decrypt_state *state, const struct link_socket_actual *from, const struct buffer *buf)
	Inspect an incoming packet for which no VPN tunnel is active, and determine whether a new VPN tunnel should be created. More...
hmac_ctx_t *	session_id_hmac_init (void)
struct session_id	calculate_session_id_hmac (struct session_id client_sid, const struct openvpn_sockaddr *from, hmac_ctx_t *hmac, int handwindow, int offset)
	Calculates the HMAC based server session id based on a client session id and socket addr. More...
bool	check_session_id_hmac (struct tls_pre_decrypt_state *state, const struct openvpn_sockaddr *from, hmac_ctx_t *hmac, int handwindow)
	Checks if a control packet has a correct HMAC server session id. More...
void	write_control_auth (struct tls_session *session, struct key_state *ks, struct buffer *buf, struct link_socket_actual **to_link_addr, int opcode, int max_ack, bool prepend_ack)
bool	read_control_auth (struct buffer *buf, struct tls_wrap_ctx *ctx, const struct link_socket_actual *from, const struct tls_options *opt)
struct buffer	tls_reset_standalone (struct tls_wrap_ctx *ctx, struct tls_auth_standalone *tas, struct session_id *own_sid, struct session_id *remote_sid, uint8_t header, bool request_resend_wkc)
	This function creates a reset packet using the information from the tls pre decrypt state. More...
static const char *	packet_opcode_name (int op)
static struct tls_wrap_ctx *	tls_session_get_tls_wrap (struct tls_session *session, int key_id)
	Determines if the current session should use the renegotiation tls wrap struct instead the normal one and returns it. More...

Macro Definition Documentation

EARLY_NEG_FLAG_RESEND_WKC

#define EARLY_NEG_FLAG_RESEND_WKC   0x0001

Definition at line 316 of file ssl_pkt.h.

EARLY_NEG_MASK

#define EARLY_NEG_MASK   0xff000000

Definition at line 307 of file ssl_pkt.h.

EARLY_NEG_START

#define EARLY_NEG_START   0x0f000000

Definition at line 308 of file ssl_pkt.h.

P_ACK_V1

#define P_ACK_V1   5 /* acknowledgement for packets received */

Definition at line 46 of file ssl_pkt.h.

P_CONTROL_HARD_RESET_CLIENT_V1

#define P_CONTROL_HARD_RESET_CLIENT_V1   1 /* initial key from client, forget previous state */

Definition at line 42 of file ssl_pkt.h.

P_CONTROL_HARD_RESET_CLIENT_V2

#define P_CONTROL_HARD_RESET_CLIENT_V2   7 /* initial key from client, forget previous state */

Definition at line 51 of file ssl_pkt.h.

P_CONTROL_HARD_RESET_CLIENT_V3

#define P_CONTROL_HARD_RESET_CLIENT_V3   10 /* initial key from client, forget previous state */

Definition at line 55 of file ssl_pkt.h.

P_CONTROL_HARD_RESET_SERVER_V1

#define P_CONTROL_HARD_RESET_SERVER_V1   2 /* initial key from server, forget previous state */

Definition at line 43 of file ssl_pkt.h.

P_CONTROL_HARD_RESET_SERVER_V2

#define P_CONTROL_HARD_RESET_SERVER_V2   8 /* initial key from server, forget previous state */

Definition at line 52 of file ssl_pkt.h.

P_CONTROL_SOFT_RESET_V1

#define P_CONTROL_SOFT_RESET_V1   3 /* new key, graceful transition from old to new key */

Definition at line 44 of file ssl_pkt.h.

P_CONTROL_V1

#define P_CONTROL_V1   4 /* control channel packet (usually TLS ciphertext) */

Definition at line 45 of file ssl_pkt.h.

P_CONTROL_WKC_V1

#define P_CONTROL_WKC_V1   11

Definition at line 59 of file ssl_pkt.h.

P_DATA_V1

#define P_DATA_V1   6 /* data channel packet */

Definition at line 47 of file ssl_pkt.h.

P_DATA_V2

#define P_DATA_V2   9 /* data channel packet with peer-id */

Definition at line 48 of file ssl_pkt.h.

P_FIRST_OPCODE

#define P_FIRST_OPCODE   3

Definition at line 64 of file ssl_pkt.h.

P_KEY_ID_MASK

#define P_KEY_ID_MASK   0x07

Definition at line 38 of file ssl_pkt.h.

P_LAST_OPCODE

#define P_LAST_OPCODE   11

Definition at line 65 of file ssl_pkt.h.

P_OPCODE_SHIFT

#define P_OPCODE_SHIFT   3

Definition at line 39 of file ssl_pkt.h.

TLS_RELIABLE_N_REC_BUFFERS

#define TLS_RELIABLE_N_REC_BUFFERS   12

Definition at line 71 of file ssl_pkt.h.

TLS_RELIABLE_N_SEND_BUFFERS

#define TLS_RELIABLE_N_SEND_BUFFERS   6 /* also window size for reliability layer */

Definition at line 70 of file ssl_pkt.h.

TLV_TYPE_EARLY_NEG_FLAGS

#define TLV_TYPE_EARLY_NEG_FLAGS   0x0001

Definition at line 315 of file ssl_pkt.h.

Enumeration Type Documentation

first_packet_verdict

enum first_packet_verdict

Enumerator
VERDICT_VALID_RESET_V2	This packet is a valid reset packet from the peer (all but tls-crypt-v2)
VERDICT_VALID_RESET_V3	This is a valid v3 reset (tls-crypt-v2)
VERDICT_VALID_CONTROL_V1	This packet is a valid control packet from the peer.
VERDICT_VALID_ACK_V1	This packet is a valid ACK control packet from the peer, i.e. it has a valid session id hmac in it
VERDICT_VALID_WKC_V1	The packet is a valid control packet with appended wrapped client key.
VERDICT_INVALID	the packet failed on of the various checks

Definition at line 84 of file ssl_pkt.h.

Function Documentation

calculate_session_id_hmac()

struct session_id calculate_session_id_hmac	(	struct session_id	client_sid,
		const struct openvpn_sockaddr *	from,
		hmac_ctx_t *	hmac,
		int	handwindow,
		int	offset
	)

Calculates the HMAC based server session id based on a client session id and socket addr.

Parameters

client_sid	session id of the client
from	link_socket from the client
hmac	the hmac context to use for the calculation
handwindow	the quantisation of the current time
offset	offset to 'now' to use

Returns

the expected server session id

Definition at line 487 of file ssl_pkt.c.

References hmac_ctx_final(), hmac_ctx_reset(), hmac_ctx_update(), now, SHA256_DIGEST_LENGTH, and SID_SIZE.

Referenced by check_session_id_hmac(), do_pre_decrypt_check(), and test_calc_session_id_hmac_static().

check_session_id_hmac()

bool check_session_id_hmac	(	struct tls_pre_decrypt_state *	state,
		const struct openvpn_sockaddr *	from,
		hmac_ctx_t *	hmac,
		int	handwindow
	)

Checks if a control packet has a correct HMAC server session id.

Parameters

client_sid	session id of the client
from	link_socket from the client
hmac	the hmac context to use for the calculation
handwindow	the quantisation of the current time

Returns

the expected server session id

Definition at line 529 of file ssl_pkt.c.

References calculate_session_id_hmac(), memcmp_constant_time(), tls_pre_decrypt_state::newbuf, tls_pre_decrypt_state::peer_session_id, reliable_ack_parse(), tls_pre_decrypt_state::server_session_id, and SID_SIZE.

Referenced by do_pre_decrypt_check(), test_verify_hmac_none(), and test_verify_hmac_tls_auth().

free_tls_pre_decrypt_state()

void free_tls_pre_decrypt_state

(

struct tls_pre_decrypt_state *

state

)

Parameters

state

Definition at line 285 of file ssl_pkt.c.

References tls_wrap_ctx::cleanup_key_ctx, free_buf(), free_key_ctx_bi(), crypto_options::key_ctx_bi, tls_pre_decrypt_state::newbuf, tls_wrap_ctx::opt, tls_wrap_ctx::tls_crypt_v2_metadata, and tls_pre_decrypt_state::tls_wrap_tmp.

Referenced by multi_get_create_instance_udp(), test_generate_reset_packet_plain(), test_generate_reset_packet_tls_auth(), test_tls_decrypt_lite_auth(), test_tls_decrypt_lite_crypt(), test_tls_decrypt_lite_none(), test_verify_hmac_none(), and test_verify_hmac_tls_auth().

packet_opcode_name()

static const char* packet_opcode_name ( int  op )

inlinestatic

Definition at line 234 of file ssl_pkt.h.

References P_ACK_V1, P_CONTROL_HARD_RESET_CLIENT_V1, P_CONTROL_HARD_RESET_CLIENT_V2, P_CONTROL_HARD_RESET_CLIENT_V3, P_CONTROL_HARD_RESET_SERVER_V1, P_CONTROL_HARD_RESET_SERVER_V2, P_CONTROL_SOFT_RESET_V1, P_CONTROL_V1, P_CONTROL_WKC_V1, P_DATA_V1, and P_DATA_V2.

Referenced by do_pre_decrypt_check(), protocol_dump(), tls_pre_decrypt(), and write_control_auth().

read_control_auth()

bool read_control_auth	(	struct buffer *	buf,
		struct tls_wrap_ctx *	ctx,
		const struct link_socket_actual *	from,
		const struct tls_options *	opt
	)

Definition at line 200 of file ssl_pkt.c.

References alloc_buf_gc(), ASSERT, BPTR, buf_advance(), buf_clear(), buf_copy(), buf_forward_capacity_total(), buf_init, key_ctx::cipher, cleanup(), clear_buf(), D_TLS_ERRORS, gc_free(), gc_new(), buffer::len, tls_wrap_ctx::mode, msg, buffer::offset, openvpn_decrypt(), tls_wrap_ctx::opt, P_CONTROL_HARD_RESET_CLIENT_V3, P_CONTROL_WKC_V1, P_OPCODE_SHIFT, print_link_socket_actual(), SID_SIZE, swap_hmac(), tls_crypt_unwrap(), tls_crypt_v2_extract_client_key(), and tls_wrap_ctx::tls_crypt_v2_server_key.

Referenced by tls_pre_decrypt(), and tls_pre_decrypt_lite().

session_id_hmac_init()

hmac_ctx_t* session_id_hmac_init

(

void

)

Definition at line 473 of file ssl_pkt.c.

References ASSERT, hmac_ctx_init(), hmac_ctx_new(), md_valid(), rand_bytes(), and SHA256_DIGEST_LENGTH.

Referenced by do_init_crypto_tls(), test_verify_hmac_none(), and test_verify_hmac_tls_auth().

tls_reset_standalone()

struct buffer tls_reset_standalone	(	struct tls_wrap_ctx *	ctx,
		struct tls_auth_standalone *	tas,
		struct session_id *	own_sid,
		struct session_id *	remote_sid,
		uint8_t	header,
		bool	request_resend_wkc
	)

This function creates a reset packet using the information from the tls pre decrypt state.

Definition at line 428 of file ssl_pkt.c.

References ASSERT, frame::buf, buf_init, buf_write(), buf_write_u16(), buf_write_u32(), buf_write_u8(), EARLY_NEG_FLAG_RESEND_WKC, tls_auth_standalone::frame, frame::headroom, htonpid, session_id::id, SID_SIZE, tls_wrap_control(), TLV_TYPE_EARLY_NEG_FLAGS, and tls_auth_standalone::workbuf.

Referenced by send_hmac_reset_packet(), test_generate_reset_packet_plain(), and test_generate_reset_packet_tls_auth().

tls_session_get_tls_wrap()

static struct tls_wrap_ctx* tls_session_get_tls_wrap ( struct tls_session *  session, int  key_id  )

inlinestatic

Determines if the current session should use the renegotiation tls wrap struct instead the normal one and returns it.

Parameters

session
key_id	key_id of the received/or to be send packet

Returns

Definition at line 285 of file ssl_pkt.h.

References tls_wrap_ctx::TLS_WRAP_CRYPT.

Referenced by tls_pre_decrypt(), and write_control_auth().

write_control_auth()

void write_control_auth	(	struct tls_session *	session,
		struct key_state *	ks,
		struct buffer *	buf,
		struct link_socket_actual **	to_link_addr,
		int	opcode,
		int	max_ack,
		bool	prepend_ack
	)

Definition at line 168 of file ssl_pkt.c.

References ASSERT, CO_USE_TLS_KEY_MATERIAL_EXPORT, D_TLS_DEBUG, key_state::key_id, link_socket_actual_defined(), key_state::lru_acks, min_int(), msg, P_OPCODE_SHIFT, packet_opcode_name(), key_state::rec_ack, reliable_ack_write(), key_state::remote_addr, key_state::session_id_remote, tls_session_get_tls_wrap(), and tls_wrap_control().

Referenced by tls_process(), and tls_process_state().