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External persistent storage for PMKSA cache entries

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This adds new wpa_supplicant control interface commands PMKSA_GET and
PMKSA_ADD that can be used to store PMKSA cache entries in an external
persistent storage when terminating a wpa_supplicant process and then
restore those entries when starting a new process. The previously added
PMKSA-CACHE-ADDED/REMOVED events can be used to help in synchronizing
the external storage with the memory-only volatile storage within
wpa_supplicant.

"PMKSA_GET <network_id>" fetches all stored PMKSA cache entries bound to
a specific network profile. The network_id of the current profile is
available with the STATUS command (id=<network_id). In addition, the
network_id is included in the PMKSA-CACHE-ADDED/REMOVED events. The
output of the PMKSA_GET command uses the following format:

<BSSID> <PMKID> <PMK> <reauth_time in seconds> <expiration in seconds>
<akmp> <opportunistic>

For example:

02:00:00:00:03:00 113b8b5dc8eda16594e8274df4caa3d4 355e98681d09e0b69d3a342f96998aa765d10c4459ac592459b5efc6b563eff6 30240 43200 1 0
02:00:00:00:04:00 bbdac8607aaaac28e16aacc9152ffe23 e3dd6adc390e685985e5f40e6fe72df846a0acadc59ba15c208d9cb41732a663 30240 43200 1 0

The PMKSA_GET command uses the following format:

<network_id> <BSSID> <PMKID> <PMK> <reauth_time in seconds> <expiration
in seconds> <akmp> <opportunistic>

(i.e., "PMKSA_ADD <network_id> " prefix followed by a line of PMKSA_GET
output data; however, the reauth_time and expiration values need to be
updated by decrementing them by number of seconds between the PMKSA_GET
and PMKSA_ADD commands)

For example:

PMKSA_ADD 0 02:00:00:00:03:00 113b8b5dc8eda16594e8274df4caa3d4 355e98681d09e0b69d3a342f96998aa765d10c4459ac592459b5efc6b563eff6 30140 43100 1 0
PMKSA_ADD 0 02:00:00:00:04:00 bbdac8607aaaac28e16aacc9152ffe23 e3dd6adc390e685985e5f40e6fe72df846a0acadc59ba15c208d9cb41732a663 30140 43100 1 0

This functionality is disabled be default and can be enabled with
CONFIG_PMKSA_CACHE_EXTERNAL=y build configuration option. It should be
noted that this allows any process that has access to the wpa_supplicant
control interface to use PMKSA_ADD command to fetch keying material
(PMK), so this is for environments in which the control interface access
is restricted.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2016-12-12 23:47:04 +02:00 committed by Jouni Malinen
parent f0df5afa08
commit 3459381dd2
9 changed files with 222 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
src/rsn_supp/pmksa_cache.c
View file

@ -129,7 +129,7 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
const u8 *pmkid, const u8 *kck, size_t kck_len,
const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
{
struct rsn_pmksa_cache_entry *entry, *pos, *prev;
struct rsn_pmksa_cache_entry *entry;
struct os_reltime now;
if (pmk_len > PMK_LEN_MAX)
@ -160,14 +160,25 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
os_memcpy(entry->aa, aa, ETH_ALEN);
entry->network_ctx = network_ctx;
return pmksa_cache_add_entry(pmksa, entry);
}
struct rsn_pmksa_cache_entry *
pmksa_cache_add_entry(struct rsn_pmksa_cache *pmksa,
struct rsn_pmksa_cache_entry *entry)
{
struct rsn_pmksa_cache_entry *pos, *prev;
/* Replace an old entry for the same Authenticator (if found) with the
* new entry */
pos = pmksa->pmksa;
prev = NULL;
while (pos) {
if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
if (pos->pmk_len == pmk_len &&
os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 &&
if (os_memcmp(entry->aa, pos->aa, ETH_ALEN) == 0) {
if (pos->pmk_len == entry->pmk_len &&
os_memcmp_const(pos->pmk, entry->pmk,
entry->pmk_len) == 0 &&
os_memcmp_const(pos->pmkid, entry->pmkid,
PMKID_LEN) == 0) {
wpa_printf(MSG_DEBUG, "WPA: reusing previous "
@ -193,8 +204,8 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
"the current AP and any PMKSA cache entry "
"that was based on the old PMK");
if (!pos->opportunistic)
pmksa_cache_flush(pmksa, network_ctx, pos->pmk,
pos->pmk_len);
pmksa_cache_flush(pmksa, entry->network_ctx,
pos->pmk, pos->pmk_len);
pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE);
break;
}
@ -245,8 +256,9 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
}
pmksa->pmksa_count++;
wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
" network_ctx=%p", MAC2STR(entry->aa), network_ctx);
wpa_sm_add_pmkid(pmksa->sm, network_ctx, entry->aa, entry->pmkid);
" network_ctx=%p", MAC2STR(entry->aa), entry->network_ctx);
wpa_sm_add_pmkid(pmksa->sm, entry->network_ctx, entry->aa,
entry->pmkid);
return entry;
}
@ -514,6 +526,12 @@ int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
}
struct rsn_pmksa_cache_entry * pmksa_cache_head(struct rsn_pmksa_cache *pmksa)
{
return pmksa->pmksa;
}
/**
* pmksa_cache_init - Initialize PMKSA cache
* @free_cb: Callback function to be called when a PMKSA cache entry is freed

4
src/rsn_supp/pmksa_cache.h
View file

@ -55,10 +55,14 @@ struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
const u8 *aa, const u8 *pmkid,
const void *network_ctx);
int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len);
struct rsn_pmksa_cache_entry * pmksa_cache_head(struct rsn_pmksa_cache *pmksa);
struct rsn_pmksa_cache_entry *
pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
const u8 *pmkid, const u8 *kck, size_t kck_len,
const u8 *aa, const u8 *spa, void *network_ctx, int akmp);
struct rsn_pmksa_cache_entry *
pmksa_cache_add_entry(struct rsn_pmksa_cache *pmksa,
struct rsn_pmksa_cache_entry *entry);
struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm);
void pmksa_cache_clear_current(struct wpa_sm *sm);
int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,

14
src/rsn_supp/wpa.c
View file

@ -3028,6 +3028,20 @@ int wpa_sm_pmksa_cache_list(struct wpa_sm *sm, char *buf, size_t len)
}
struct rsn_pmksa_cache_entry * wpa_sm_pmksa_cache_head(struct wpa_sm *sm)
{
return pmksa_cache_head(sm->pmksa);
}
struct rsn_pmksa_cache_entry *
wpa_sm_pmksa_cache_add_entry(struct wpa_sm *sm,
struct rsn_pmksa_cache_entry * entry)
{
return pmksa_cache_add_entry(sm->pmksa, entry);
}
void wpa_sm_drop_sa(struct wpa_sm *sm)
{
wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: Clear old PMK and PTK");

4
src/rsn_supp/wpa.h
View file

@ -149,6 +149,10 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, const u8 *src_addr,
const u8 *buf, size_t len);
int wpa_sm_parse_own_wpa_ie(struct wpa_sm *sm, struct wpa_ie_data *data);
int wpa_sm_pmksa_cache_list(struct wpa_sm *sm, char *buf, size_t len);
struct rsn_pmksa_cache_entry * wpa_sm_pmksa_cache_head(struct wpa_sm *sm);
struct rsn_pmksa_cache_entry *
wpa_sm_pmksa_cache_add_entry(struct wpa_sm *sm,
struct rsn_pmksa_cache_entry * entry);
void wpa_sm_drop_sa(struct wpa_sm *sm);
int wpa_sm_has_ptk(struct wpa_sm *sm);

4
wpa_supplicant/Android.mk
View file

@ -270,6 +270,10 @@ ifdef CONFIG_PEERKEY
L_CFLAGS += -DCONFIG_PEERKEY
endif
ifdef CONFIG_PMKSA_CACHE_EXTERNAL
L_CFLAGS += -DCONFIG_PMKSA_CACHE_EXTERNAL
endif
ifndef CONFIG_NO_WPA
OBJS += src/rsn_supp/wpa.c
OBJS += src/rsn_supp/preauth.c

4
wpa_supplicant/Makefile
View file

@ -303,6 +303,10 @@ ifdef CONFIG_PEERKEY
CFLAGS += -DCONFIG_PEERKEY
endif
ifdef CONFIG_PMKSA_CACHE_EXTERNAL
CFLAGS += -DCONFIG_PMKSA_CACHE_EXTERNAL
endif
ifndef CONFIG_NO_WPA
OBJS += ../src/rsn_supp/wpa.o
OBJS += ../src/rsn_supp/preauth.o

5
wpa_supplicant/android.config
View file

@ -489,4 +489,9 @@ CONFIG_WIFI_DISPLAY=y
# Support Multi Band Operation
#CONFIG_MBO=y
# External PMKSA cache control
# This can be used to enable control interface commands that allow the current
# PMKSA cache entries to be fetched and new entries to be added.
#CONFIG_PMKSA_CACHE_EXTERNAL=y
include $(wildcard $(LOCAL_PATH)/android_config_*.inc)

156
wpa_supplicant/ctrl_iface.c
View file

@ -8714,6 +8714,154 @@ static void wpas_ctrl_iface_pmksa_flush(struct wpa_supplicant *wpa_s)
}
#ifdef CONFIG_PMKSA_CACHE_EXTERNAL
static int wpas_ctrl_iface_pmksa_get(struct wpa_supplicant *wpa_s,
const char *cmd, char *buf, size_t buflen)
{
struct rsn_pmksa_cache_entry *entry;
struct wpa_ssid *ssid;
char *pos, *pos2, *end;
int ret;
struct os_reltime now;
ssid = wpa_config_get_network(wpa_s->conf, atoi(cmd));
if (!ssid)
return -1;
pos = buf;
end = buf + buflen;
os_get_reltime(&now);
/*
* Entry format:
* <BSSID> <PMKID> <PMK> <reauth_time in seconds>
* <expiration in seconds> <akmp> <opportunistic>
*/
for (entry = wpa_sm_pmksa_cache_head(wpa_s->wpa); entry;
entry = entry->next) {
if (entry->network_ctx != ssid)
continue;
pos2 = pos;
ret = os_snprintf(pos2, end - pos2, MACSTR " ",
MAC2STR(entry->aa));
if (os_snprintf_error(end - pos2, ret))
break;
pos2 += ret;
pos2 += wpa_snprintf_hex(pos2, end - pos2, entry->pmkid,
PMKID_LEN);
ret = os_snprintf(pos2, end - pos2, " ");
if (os_snprintf_error(end - pos2, ret))
break;
pos2 += ret;
pos2 += wpa_snprintf_hex(pos2, end - pos2, entry->pmk,
entry->pmk_len);
ret = os_snprintf(pos2, end - pos2, " %d %d %d %d",
(int) (entry->reauth_time - now.sec),
(int) (entry->expiration - now.sec),
entry->akmp,
entry->opportunistic);
if (os_snprintf_error(end - pos2, ret))
break;
pos2 += ret;
ret = os_snprintf(pos2, end - pos2, "\n");
if (os_snprintf_error(end - pos2, ret))
break;
pos2 += ret;
pos = pos2;
}
return pos - buf;
}
static int wpas_ctrl_iface_pmksa_add(struct wpa_supplicant *wpa_s,
char *cmd)
{
struct rsn_pmksa_cache_entry *entry;
struct wpa_ssid *ssid;
char *pos, *pos2;
int ret = -1;
struct os_reltime now;
int reauth_time = 0, expiration = 0;
/*
* Entry format:
* <network_id> <BSSID> <PMKID> <PMK> <reauth_time in seconds>
* <expiration in seconds> <akmp> <opportunistic>
*/
ssid = wpa_config_get_network(wpa_s->conf, atoi(cmd));
if (!ssid)
return -1;
pos = os_strchr(cmd, ' ');
if (!pos)
return -1;
pos++;
entry = os_zalloc(sizeof(*entry));
if (!entry)
return -1;
if (hwaddr_aton(pos, entry->aa))
goto fail;
pos = os_strchr(pos, ' ');
if (!pos)
goto fail;
pos++;
if (hexstr2bin(pos, entry->pmkid, PMKID_LEN) < 0)
goto fail;
pos = os_strchr(pos, ' ');
if (!pos)
goto fail;
pos++;
pos2 = os_strchr(pos, ' ');
if (!pos2)
goto fail;
entry->pmk_len = (pos2 - pos) / 2;
if (entry->pmk_len < PMK_LEN || entry->pmk_len > PMK_LEN_MAX ||
hexstr2bin(pos, entry->pmk, entry->pmk_len) < 0)
goto fail;
pos = os_strchr(pos, ' ');
if (!pos)
goto fail;
pos++;
if (sscanf(pos, "%d %d %d %d", &reauth_time, &expiration,
&entry->akmp, &entry->opportunistic) != 4)
goto fail;
os_get_reltime(&now);
entry->expiration = now.sec + expiration;
entry->reauth_time = now.sec + reauth_time;
entry->network_ctx = ssid;
wpa_sm_pmksa_cache_add_entry(wpa_s->wpa, entry);
entry = NULL;
ret = 0;
fail:
os_free(entry);
return ret;
}
#endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
static int wpas_ctrl_cmd_debug_level(const char *cmd)
{
if (os_strcmp(cmd, "PING") == 0 ||
@ -8788,6 +8936,14 @@ char * wpa_supplicant_ctrl_iface_process(struct wpa_supplicant *wpa_s,
reply_len = wpas_ctrl_iface_pmksa(wpa_s, reply, reply_size);
} else if (os_strcmp(buf, "PMKSA_FLUSH") == 0) {
wpas_ctrl_iface_pmksa_flush(wpa_s);
#ifdef CONFIG_PMKSA_CACHE_EXTERNAL
} else if (os_strncmp(buf, "PMKSA_GET ", 10) == 0) {
reply_len = wpas_ctrl_iface_pmksa_get(wpa_s, buf + 10,
reply, reply_size);
} else if (os_strncmp(buf, "PMKSA_ADD ", 10) == 0) {
if (wpas_ctrl_iface_pmksa_add(wpa_s, buf + 10) < 0)
reply_len = -1;
#endif /* CONFIG_PMKSA_CACHE_EXTERNAL */
} else if (os_strncmp(buf, "SET ", 4) == 0) {
if (wpa_supplicant_ctrl_iface_set(wpa_s, buf + 4))
reply_len = -1;

5
wpa_supplicant/defconfig
View file

@ -562,3 +562,8 @@ CONFIG_PEERKEY=y
# This is needed to be able to use mode=1 network profile with proto=RSN and
# key_mgmt=WPA-PSK (i.e., full key management instead of WPA-None).
#CONFIG_IBSS_RSN=y
# External PMKSA cache control
# This can be used to enable control interface commands that allow the current
# PMKSA cache entries to be fetched and new entries to be added.
#CONFIG_PMKSA_CACHE_EXTERNAL=y