[PATCH 09/15] handshake: Add pmksa setter & stealer

James Prestwood
2024-11-22T15:16:10Z

From: Denis Kenzior <denkenz@gmail.com>

The majority of this patch was authored by Denis Kenzior, but
I have appended setting the PMK inside handshake_state_set_pmksa
as well as checking if the pmkid exists in
handshake_state_steal_pmkid.

Authored-by: Denis Kenzior <denkenz@gmail.com>
Authored-by: James Prestwood <prestwoj@gmail.com>
---
Makefile.am | 4 +++
src/handshake.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
src/handshake.h | 11 ++++++-
3 files changed, 91 insertions(+), 1 deletion(-)

diff --git a/Makefile.am b/Makefile.am
index 598b8f90..89198289 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -458,6 +458,7 @@ unit_test_eap_sim_SOURCES = unit/test-eap-sim.c \
src/eapol.h src/eapol.c \
src/eapolutil.h src/eapolutil.c \
src/handshake.h src/handshake.c \
+ src/pmksa.h src/pmksa.c \
src/eap.h src/eap.c src/eap-private.h \
src/util.h src/util.c \
src/simauth.h src/simauth.c \
@@ -517,6 +518,7 @@ unit_test_eapol_SOURCES = unit/test-eapol.c \
src/eapol.h src/eapol.c \
src/eapolutil.h src/eapolutil.c \
src/handshake.h src/handshake.c \
+ src/pmksa.h src/pmksa.c \
src/eap.h src/eap.c src/eap-private.h \
src/eap-tls.c src/eap-ttls.c \
src/eap-md5.c src/util.c \
@@ -547,6 +549,7 @@ unit_test_wsc_SOURCES = unit/test-wsc.c src/wscutil.h src/wscutil.c \
src/eapol.h src/eapol.c \
src/eapolutil.h src/eapolutil.c \
src/handshake.h src/handshake.c \
+ src/pmksa.h src/pmksa.c \
src/eap.h src/eap.c src/eap-private.h \
src/util.h src/util.c \
src/erp.h src/erp.c \
@@ -565,6 +568,7 @@ unit_test_sae_SOURCES = unit/test-sae.c \
src/crypto.h src/crypto.c \
src/ie.h src/ie.c \
src/handshake.h src/handshake.c \
+ src/pmksa.h src/pmksa.c \
src/erp.h src/erp.c \
src/band.h src/band.c \
src/util.h src/util.c \
diff --git a/src/handshake.c b/src/handshake.c
index 7fb75dc4..a93143d1 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -43,6 +43,7 @@
#include "src/handshake.h"
#include "src/erp.h"
#include "src/band.h"
+#include "src/pmksa.h"

static inline unsigned int n_ecc_groups(void)
{
@@ -138,6 +139,9 @@ void handshake_state_unref(struct handshake_state *s)
l_free(s->fils_ip_resp_ie);
l_free(s->vendor_ies);

+ if (s->have_pmksa)
+ l_free(s->pmksa);
+
if (s->erp_cache)
erp_cache_put(s->erp_cache);

@@ -701,6 +705,11 @@ void handshake_state_install_ptk(struct handshake_state *s)
{
s->ptk_complete = true;

+ if (!s->have_pmksa && IE_AKM_IS_SAE(s->akm_suite)) {
+ l_debug("Adding PMKSA expiration");
+ s->expiration = l_time_now() + pmksa_lifetime();
+ }
+
if (install_tk) {
uint32_t cipher = ie_rsn_cipher_suite_to_cipher(
s->pairwise_cipher);
@@ -1203,3 +1212,71 @@ done:

return r;
}
+
+bool handshake_state_set_pmksa(struct handshake_state *s,
+ struct pmksa *pmksa)
+{
+ /* checks for both expiration || pmksa being set */
+ if (s->expiration)
+ return false;
+
+ s->pmksa = pmksa;
+ s->have_pmksa = true;
+
+ handshake_state_set_pmkid(s, pmksa->pmkid);
+ handshake_state_set_pmk(s, pmksa->pmk, pmksa->pmk_len);
+
+ return true;
+}
+
+static struct pmksa *handshake_state_steal_pmksa(struct handshake_state *s)
+{
+ struct pmksa *pmksa;
+ uint64_t now = l_time_now();
+
+ if (s->have_pmksa) {
+ pmksa = l_steal_ptr(s->pmksa);
+ s->have_pmksa = false;
+
+ if (l_time_after(now, pmksa->expiration)) {
+ l_free(pmksa);
+ pmksa = NULL;
+ }
+
+ return pmksa;
+ }
+
+ if (s->expiration && l_time_after(now, s->expiration)) {
+ s->expiration = 0;
+ return NULL;
+ }
+
+ if (!s->have_pmkid)
+ return NULL;
+
+ pmksa = l_new(struct pmksa, 1);
+ pmksa->expiration = s->expiration;
+ memcpy(pmksa->spa, s->spa, sizeof(s->spa));
+ memcpy(pmksa->aa, s->aa, sizeof(s->aa));
+ memcpy(pmksa->ssid, s->ssid, s->ssid_len);
+ pmksa->ssid_len = s->ssid_len;
+ pmksa->akm = s->akm_suite;
+ memcpy(pmksa->pmkid, s->pmkid, sizeof(s->pmkid));
+ pmksa->pmk_len = s->pmk_len;
+ memcpy(pmksa->pmk, s->pmk, s->pmk_len);
+
+ return pmksa;
+}
+
+void handshake_state_cache_pmksa(struct handshake_state *s)
+{
+ struct pmksa *pmksa = handshake_state_steal_pmksa(s);
+
+ l_debug("%p", pmksa);
+
+ if (!pmksa)
+ return;
+
+ if (L_WARN_ON(pmksa_cache_put(pmksa) < 0))
+ l_free(pmksa);
+}
diff --git a/src/handshake.h b/src/handshake.h
index 6c0946d4..cf7dc48c 100644
--- a/src/handshake.h
+++ b/src/handshake.h
@@ -29,6 +29,7 @@
struct handshake_state;
enum crypto_cipher;
struct eapol_frame;
+struct pmksa;

enum handshake_kde {
/* 802.11-2020 Table 12-9 in section 12.7.2 */
@@ -141,7 +142,12 @@ struct handshake_state {
bool supplicant_ocvc : 1;
bool ext_key_id_capable : 1;
bool force_default_ecc_group : 1;
- uint8_t ssid[SSID_MAX_SIZE];
+ bool have_pmksa : 1;
+ union {
+ struct pmksa *pmksa;
+ uint64_t expiration;
+ };
+ uint8_t ssid[32];
size_t ssid_len;
char *passphrase;
char *password_identifier;
@@ -302,6 +308,9 @@ void handshake_state_set_chandef(struct handshake_state *s,
int handshake_state_verify_oci(struct handshake_state *s, const uint8_t *oci,
size_t oci_len);

+bool handshake_state_set_pmksa(struct handshake_state *s, struct pmksa *pmksa);
+void handshake_state_cache_pmksa(struct handshake_state *s);
+
bool handshake_util_ap_ie_matches(const struct ie_rsn_info *msg_info,
const uint8_t *scan_ie, bool is_wpa);

--
2.34.1