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ikev2: return STF_FATAL when REKEY_CHILD payload is corrupt
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@cagney @paulwouters
cagney authored and paulwouters committed Aug 8, 2023
1 parent f9d9036 commit 94543f8
Showing 1 changed file with 89 additions and 60 deletions.
149 changes: 89 additions & 60 deletions programs/pluto/ikev2_create_child_sa.c
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Original file line number Diff line number Diff line change
Expand Up @@ -175,80 +175,102 @@ static void emancipate_larval_ike_sa(struct ike_sa *old_ike, struct child_sa *ne
release_whack(new_ike->sa.st_logger, HERE);
}

static struct child_sa *find_v2N_REKEY_SA_child(struct ike_sa *ike,
struct msg_digest *md)
/*
* Find the Child SA identified by the v2N_REKEY_SA payload.
*
* FALSE: payload corrupt; caller should respond with the fatal
* v2N_INVALID_SYNTAX.
*
* TRUE, CHILD==NULL: payload ok but no matching Child SA was
* found. The v2N_CHILD_SA_NOT_FOUND response already recorded using
* information extracted from the rekey notify payload.
*
* TRUE, CHILD!=NULL: payload ok, matching Child SA found.
*/

static bool find_v2N_REKEY_SA_child(struct ike_sa *ike,
struct msg_digest *md,
struct child_sa **child)
{
*child = NULL;

/*
* Previously found by the state machine.
* Previously decoded and minimially validated by the state
* machine using ikev2_notify_desc (i.e., more validation
* required).
*/

const struct payload_digest *rekey_sa_payload = md->pd[PD_v2N_REKEY_SA];
if (rekey_sa_payload == NULL) {
llog_pexpect(ike->sa.st_logger, HERE,
"rekey child can't find its rekey_sa payload");
return NULL;
}
#if 0
/* XXX: this would require a separate .pd_next link? */
if (rekey_sa_payload->next != NULL) {
/* will tolerate multiple */
log_state(RC_LOG_SERIOUS, &ike->sa,
"ignoring duplicate v2N_REKEY_SA in exchange");
return false;
}
#endif

const struct ikev2_notify *rekey_notify = &rekey_sa_payload->payload.v2n;

/*
* find old state to rekey
* Check the protocol.
*
* "ikev2_notify_desc" allows 0, IKE, ESP and AH; reject the
* first two. Will also need to check that the protocl
* matches that extablished by the Child SA.
*/

const struct ikev2_notify *rekey_notify = &rekey_sa_payload->payload.v2n;
if (rekey_notify->isan_protoid != PROTO_IPSEC_ESP &&
rekey_notify->isan_protoid != PROTO_IPSEC_AH) {
esb_buf b;
llog_sa(RC_LOG, ike,
"CREATE_CHILD_SA IPsec SA rekey invalid Protocol ID %s",
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));
return false;
}

#ifndef ldbg_sa
#define ldbg_sa(SA, ...) ldbg((SA)->sa.st_logger, __VA_ARGS__)
#endif

esb_buf b;
dbg("CREATE_CHILD_SA IPsec SA rekey Protocol %s",
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));
ldbg_sa(ike, "CREATE_CHILD_SA IPsec SA rekey Protocol %s",
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));

/*
* Get the SPI.
*
* The SPI (and the protoid?) can be used to find the Child SA
* to rekey.
*/

if (rekey_notify->isan_spisize != sizeof(ipsec_spi_t)) {
log_state(RC_LOG, &ike->sa,
"CREATE_CHILD_SA IPsec SA rekey invalid spi size %u",
rekey_notify->isan_spisize);
record_v2N_response(ike->sa.st_logger, ike, md, v2N_INVALID_SYNTAX,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return NULL;
llog_sa(RC_LOG, ike,
"CREATE_CHILD_SA IPsec SA rekey invalid spi size %u",
rekey_notify->isan_spisize);
return false;
}

ipsec_spi_t spi = 0;
#ifndef pbs_in_thing
#define pbs_in_thing(PBS, THING, NAME) pbs_in_raw(PBS, &(THING), sizeof(THING), NAME)
#endif

ipsec_spi_t spi = 0; /* network ordered */
struct pbs_in rekey_pbs = rekey_sa_payload->pbs;
diag_t d = pbs_in_raw(&rekey_pbs, &spi, sizeof(spi), "SPI");
diag_t d = pbs_in_thing(&rekey_pbs, spi, "SPI");
if (d != NULL) {
/* for instance, truncated SPI */
llog_diag(RC_LOG, ike->sa.st_logger, &d, "%s", "");
record_v2N_response(ike->sa.st_logger, ike, md, v2N_INVALID_SYNTAX,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return NULL; /* cannot happen; XXX: why? */
return false;
}

if (spi == 0) {
log_state(RC_LOG, &ike->sa,
"CREATE_CHILD_SA IPsec SA rekey contains zero SPI");
record_v2N_response(ike->sa.st_logger, ike, md, v2N_INVALID_SYNTAX,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return NULL;
}

if (rekey_notify->isan_protoid != PROTO_IPSEC_ESP &&
rekey_notify->isan_protoid != PROTO_IPSEC_AH) {
esb_buf b;
log_state(RC_LOG, &ike->sa,
"CREATE_CHILD_SA IPsec SA rekey invalid Protocol ID %s",
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));
record_v2N_spi_response(ike->sa.st_logger, ike, md,
rekey_notify->isan_protoid, &spi,
v2N_CHILD_SA_NOT_FOUND,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return NULL;
llog_sa(RC_LOG, ike,
"CREATE_CHILD_SA IPsec SA rekey contains zero SPI");
return false;
}

esb_buf protoesb;
dbg("CREATE_CHILD_S to rekey IPsec SA(0x%08" PRIx32 ") Protocol %s",
ntohl((uint32_t) spi),
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &protoesb));
ldbg_sa(ike, "CREATE_CHILD_SA to rekey IPsec SA(0x%08" PRIx32 ") Protocol %s",
ntohl((uint32_t) spi),
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &protoesb));

/*
* From 1.3.3. Rekeying Child SAs with the CREATE_CHILD_SA
Expand All @@ -257,29 +279,31 @@ static struct child_sa *find_v2N_REKEY_SA_child(struct ike_sa *ike,
* exchange initiator would expect in inbound ESP or AH
* packets.
*
* From our POV, that's the outbound SPI.
* From our, the responder's POV, that's the outbound SPI.
*/

struct child_sa *replaced_child = find_v2_child_sa_by_outbound_spi(ike, rekey_notify->isan_protoid, spi);
if (replaced_child == NULL) {
esb_buf b;
log_state(RC_LOG, &ike->sa,
"CREATE_CHILD_SA no such IPsec SA to rekey SA(0x%08" PRIx32 ") Protocol %s",
ntohl((uint32_t) spi),
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));
llog_sa(RC_LOG, ike,
"CREATE_CHILD_SA no such IPsec SA to rekey SA(0x%08" PRIx32 ") Protocol %s",
ntohl((uint32_t) spi),
enum_show(&ikev2_notify_protocol_id_names, rekey_notify->isan_protoid, &b));
record_v2N_spi_response(ike->sa.st_logger, ike, md,
rekey_notify->isan_protoid, &spi,
v2N_CHILD_SA_NOT_FOUND,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return NULL;
return true;
}

connection_buf cb;
dbg("#%lu hasa a rekey request for "PRI_CONNECTION" #%lu TSi TSr",
ike->sa.st_serialno,
pri_connection(replaced_child->sa.st_connection, &cb),
replaced_child->sa.st_serialno);
ldbg_sa(ike, "#%lu hasa a rekey request for "PRI_CONNECTION" #%lu TSi TSr",
ike->sa.st_serialno,
pri_connection(replaced_child->sa.st_connection, &cb),
replaced_child->sa.st_serialno);

return replaced_child;
*child = replaced_child;
return true;
}

static bool record_v2_rekey_ike_message(struct ike_sa *ike,
Expand Down Expand Up @@ -638,8 +662,13 @@ stf_status process_v2_CREATE_CHILD_SA_rekey_child_request(struct ike_sa *ike,
struct child_sa *larval_child,
struct msg_digest *md)
{
struct child_sa *predecessor = NULL;
if (!find_v2N_REKEY_SA_child(ike, md, &predecessor)) {
record_v2N_response(ike->sa.st_logger, ike, md, v2N_INVALID_SYNTAX,
NULL/*empty data*/, ENCRYPTED_PAYLOAD);
return STF_FATAL;
}

struct child_sa *predecessor = find_v2N_REKEY_SA_child(ike, md);
if (predecessor == NULL) {
/* already logged; already recorded */
return STF_OK; /*IKE*/
Expand Down

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