From: Alexis Lothoré alexis.lothore@bootlin.com
[ Upstream commit 205c50306acf58a335eb19fa84e40140f4fe814f ]
With lockdep enabled, calls to the connect function from cfg802.11 layer lead to the following warning:
============================= WARNING: suspicious RCU usage 6.7.0-rc1-wt+ #333 Not tainted ----------------------------- drivers/net/wireless/microchip/wilc1000/hif.c:386 suspicious rcu_dereference_check() usage! [...] stack backtrace: CPU: 0 PID: 100 Comm: wpa_supplicant Not tainted 6.7.0-rc1-wt+ #333 Hardware name: Atmel SAMA5 unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x34/0x48 dump_stack_lvl from wilc_parse_join_bss_param+0x7dc/0x7f4 wilc_parse_join_bss_param from connect+0x2c4/0x648 connect from cfg80211_connect+0x30c/0xb74 cfg80211_connect from nl80211_connect+0x860/0xa94 nl80211_connect from genl_rcv_msg+0x3fc/0x59c genl_rcv_msg from netlink_rcv_skb+0xd0/0x1f8 netlink_rcv_skb from genl_rcv+0x2c/0x3c genl_rcv from netlink_unicast+0x3b0/0x550 netlink_unicast from netlink_sendmsg+0x368/0x688 netlink_sendmsg from ____sys_sendmsg+0x190/0x430 ____sys_sendmsg from ___sys_sendmsg+0x110/0x158 ___sys_sendmsg from sys_sendmsg+0xe8/0x150 sys_sendmsg from ret_fast_syscall+0x0/0x1c
This warning is emitted because in the connect path, when trying to parse target BSS parameters, we dereference a RCU pointer whithout being in RCU critical section. Fix RCU dereference usage by moving it to a RCU read critical section. To avoid wrapping the whole wilc_parse_join_bss_param under the critical section, just use the critical section to copy ies data
Fixes: c460495ee072 ("staging: wilc1000: fix incorrent type in initializer") Signed-off-by: Alexis Lothoré alexis.lothore@bootlin.com Signed-off-by: Kalle Valo kvalo@kernel.org Link: https://msgid.link/20240105075733.36331-3-alexis.lothore@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/microchip/wilc1000/hif.c | 36 ++++++++++++------- 1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/drivers/net/wireless/microchip/wilc1000/hif.c b/drivers/net/wireless/microchip/wilc1000/hif.c index 00ecf14afab01..5eb02902e875a 100644 --- a/drivers/net/wireless/microchip/wilc1000/hif.c +++ b/drivers/net/wireless/microchip/wilc1000/hif.c @@ -374,38 +374,49 @@ static void handle_connect_timeout(struct work_struct *work) void *wilc_parse_join_bss_param(struct cfg80211_bss *bss, struct cfg80211_crypto_settings *crypto) { - const struct cfg80211_bss_ies *ies = rcu_dereference(bss->ies); - const u8 *tim_elm, *ssid_elm, *rates_ie, *supp_rates_ie; + const u8 *ies_data, *tim_elm, *ssid_elm, *rates_ie, *supp_rates_ie; const u8 *ht_ie, *wpa_ie, *wmm_ie, *rsn_ie; struct ieee80211_p2p_noa_attr noa_attr; + const struct cfg80211_bss_ies *ies; struct wilc_join_bss_param *param; - u8 rates_len = 0; + u8 rates_len = 0, ies_len; int ret;
param = kzalloc(sizeof(*param), GFP_KERNEL); if (!param) return NULL;
+ rcu_read_lock(); + ies = rcu_dereference(bss->ies); + ies_data = kmemdup(ies->data, ies->len, GFP_ATOMIC); + if (!ies_data) { + rcu_read_unlock(); + kfree(param); + return NULL; + } + ies_len = ies->len; + rcu_read_unlock(); + param->beacon_period = cpu_to_le16(bss->beacon_interval); param->cap_info = cpu_to_le16(bss->capability); param->bss_type = WILC_FW_BSS_TYPE_INFRA; param->ch = ieee80211_frequency_to_channel(bss->channel->center_freq); ether_addr_copy(param->bssid, bss->bssid);
- ssid_elm = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len); + ssid_elm = cfg80211_find_ie(WLAN_EID_SSID, ies_data, ies_len); if (ssid_elm) { if (ssid_elm[1] <= IEEE80211_MAX_SSID_LEN) memcpy(param->ssid, ssid_elm + 2, ssid_elm[1]); }
- tim_elm = cfg80211_find_ie(WLAN_EID_TIM, ies->data, ies->len); + tim_elm = cfg80211_find_ie(WLAN_EID_TIM, ies_data, ies_len); if (tim_elm && tim_elm[1] >= 2) param->dtim_period = tim_elm[3];
memset(param->p_suites, 0xFF, 3); memset(param->akm_suites, 0xFF, 3);
- rates_ie = cfg80211_find_ie(WLAN_EID_SUPP_RATES, ies->data, ies->len); + rates_ie = cfg80211_find_ie(WLAN_EID_SUPP_RATES, ies_data, ies_len); if (rates_ie) { rates_len = rates_ie[1]; if (rates_len > WILC_MAX_RATES_SUPPORTED) @@ -416,7 +427,7 @@ void *wilc_parse_join_bss_param(struct cfg80211_bss *bss,
if (rates_len < WILC_MAX_RATES_SUPPORTED) { supp_rates_ie = cfg80211_find_ie(WLAN_EID_EXT_SUPP_RATES, - ies->data, ies->len); + ies_data, ies_len); if (supp_rates_ie) { u8 ext_rates = supp_rates_ie[1];
@@ -431,11 +442,11 @@ void *wilc_parse_join_bss_param(struct cfg80211_bss *bss, } }
- ht_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY, ies->data, ies->len); + ht_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY, ies_data, ies_len); if (ht_ie) param->ht_capable = true;
- ret = cfg80211_get_p2p_attr(ies->data, ies->len, + ret = cfg80211_get_p2p_attr(ies_data, ies_len, IEEE80211_P2P_ATTR_ABSENCE_NOTICE, (u8 *)&noa_attr, sizeof(noa_attr)); if (ret > 0) { @@ -459,7 +470,7 @@ void *wilc_parse_join_bss_param(struct cfg80211_bss *bss, } wmm_ie = cfg80211_find_vendor_ie(WLAN_OUI_MICROSOFT, WLAN_OUI_TYPE_MICROSOFT_WMM, - ies->data, ies->len); + ies_data, ies_len); if (wmm_ie) { struct ieee80211_wmm_param_ie *ie;
@@ -474,13 +485,13 @@ void *wilc_parse_join_bss_param(struct cfg80211_bss *bss,
wpa_ie = cfg80211_find_vendor_ie(WLAN_OUI_MICROSOFT, WLAN_OUI_TYPE_MICROSOFT_WPA, - ies->data, ies->len); + ies_data, ies_len); if (wpa_ie) { param->mode_802_11i = 1; param->rsn_found = true; }
- rsn_ie = cfg80211_find_ie(WLAN_EID_RSN, ies->data, ies->len); + rsn_ie = cfg80211_find_ie(WLAN_EID_RSN, ies_data, ies_len); if (rsn_ie) { int rsn_ie_len = sizeof(struct element) + rsn_ie[1]; int offset = 8; @@ -514,6 +525,7 @@ void *wilc_parse_join_bss_param(struct cfg80211_bss *bss, param->akm_suites[i] = crypto->akm_suites[i] & 0xFF; }
+ kfree(ies_data); return (void *)param; }