* [PATCH 1/2] mac80211: Reject malformed SSID elements
@ 2019-10-04 9:51 Will Deacon
2019-10-04 9:51 ` [PATCH 2/2] cfg80211: wext: " Will Deacon
2019-10-04 15:55 ` [PATCH 1/2] mac80211: " Kees Cook
0 siblings, 2 replies; 4+ messages in thread
From: Will Deacon @ 2019-10-04 9:51 UTC (permalink / raw)
To: linux-wireless; +Cc: nico, Will Deacon, stable, Johannes Berg, Kees Cook
Although this shouldn't occur in practice, it's a good idea to bounds
check the length field of the SSID element prior to using it for things
like allocations or memcpy operations.
Cc: <stable@vger.kernel.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Nicolas Waisman <nico@semmle.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
net/mac80211/mlme.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 26a2f49208b6..54dd8849d1cc 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2633,7 +2633,8 @@ struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw,
rcu_read_lock();
ssid = ieee80211_bss_get_ie(cbss, WLAN_EID_SSID);
- if (WARN_ON_ONCE(ssid == NULL))
+ if (WARN_ONCE(!ssid || ssid[1] > IEEE80211_MAX_SSID_LEN,
+ "invalid SSID element (len=%d)", ssid ? ssid[1] : -1))
ssid_len = 0;
else
ssid_len = ssid[1];
@@ -5233,7 +5234,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
rcu_read_lock();
ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID);
- if (!ssidie) {
+ if (!ssidie || ssidie[1] > sizeof(assoc_data->ssid)) {
rcu_read_unlock();
kfree(assoc_data);
return -EINVAL;
--
2.23.0.581.g78d2f28ef7-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/2] cfg80211: wext: Reject malformed SSID elements
2019-10-04 9:51 [PATCH 1/2] mac80211: Reject malformed SSID elements Will Deacon
@ 2019-10-04 9:51 ` Will Deacon
2019-10-04 15:56 ` Kees Cook
2019-10-04 15:55 ` [PATCH 1/2] mac80211: " Kees Cook
1 sibling, 1 reply; 4+ messages in thread
From: Will Deacon @ 2019-10-04 9:51 UTC (permalink / raw)
To: linux-wireless; +Cc: nico, Will Deacon, stable, Johannes Berg, Kees Cook
Ensure the SSID element is bounds-checked prior to invoking memcpy()
with its length field.
Cc: <stable@vger.kernel.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Nicolas Waisman <nico@semmle.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
net/wireless/wext-sme.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index c67d7a82ab13..3fd2cc7fc36a 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -201,6 +201,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *ssid)
{
+ int ret = 0;
struct wireless_dev *wdev = dev->ieee80211_ptr;
/* call only for station! */
@@ -219,7 +220,10 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
if (ie) {
data->flags = 1;
data->length = ie[1];
- memcpy(ssid, ie + 2, data->length);
+ if (data->length > IW_ESSID_MAX_SIZE)
+ ret = -EINVAL;
+ else
+ memcpy(ssid, ie + 2, data->length);
}
rcu_read_unlock();
} else if (wdev->wext.connect.ssid && wdev->wext.connect.ssid_len) {
@@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
}
wdev_unlock(wdev);
- return 0;
+ return ret;
}
int cfg80211_mgd_wext_siwap(struct net_device *dev,
--
2.23.0.581.g78d2f28ef7-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 2/2] cfg80211: wext: Reject malformed SSID elements
2019-10-04 9:51 ` [PATCH 2/2] cfg80211: wext: " Will Deacon
@ 2019-10-04 15:56 ` Kees Cook
0 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2019-10-04 15:56 UTC (permalink / raw)
To: Will Deacon; +Cc: linux-wireless, nico, stable, Johannes Berg
On Fri, Oct 04, 2019 at 10:51:32AM +0100, Will Deacon wrote:
> Ensure the SSID element is bounds-checked prior to invoking memcpy()
> with its length field.
>
> Cc: <stable@vger.kernel.org>
> Cc: Johannes Berg <johannes@sipsolutions.net>
> Cc: Kees Cook <keescook@chromium.org>
> Reported-by: Nicolas Waisman <nico@semmle.com>
> Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> net/wireless/wext-sme.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
> index c67d7a82ab13..3fd2cc7fc36a 100644
> --- a/net/wireless/wext-sme.c
> +++ b/net/wireless/wext-sme.c
> @@ -201,6 +201,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
> struct iw_request_info *info,
> struct iw_point *data, char *ssid)
> {
> + int ret = 0;
> struct wireless_dev *wdev = dev->ieee80211_ptr;
>
> /* call only for station! */
> @@ -219,7 +220,10 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
> if (ie) {
> data->flags = 1;
> data->length = ie[1];
> - memcpy(ssid, ie + 2, data->length);
> + if (data->length > IW_ESSID_MAX_SIZE)
> + ret = -EINVAL;
> + else
> + memcpy(ssid, ie + 2, data->length);
> }
> rcu_read_unlock();
> } else if (wdev->wext.connect.ssid && wdev->wext.connect.ssid_len) {
> @@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
> }
> wdev_unlock(wdev);
>
> - return 0;
> + return ret;
> }
>
> int cfg80211_mgd_wext_siwap(struct net_device *dev,
> --
> 2.23.0.581.g78d2f28ef7-goog
>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] mac80211: Reject malformed SSID elements
2019-10-04 9:51 [PATCH 1/2] mac80211: Reject malformed SSID elements Will Deacon
2019-10-04 9:51 ` [PATCH 2/2] cfg80211: wext: " Will Deacon
@ 2019-10-04 15:55 ` Kees Cook
1 sibling, 0 replies; 4+ messages in thread
From: Kees Cook @ 2019-10-04 15:55 UTC (permalink / raw)
To: Will Deacon; +Cc: linux-wireless, nico, stable, Johannes Berg
On Fri, Oct 04, 2019 at 10:51:31AM +0100, Will Deacon wrote:
> Although this shouldn't occur in practice, it's a good idea to bounds
> check the length field of the SSID element prior to using it for things
> like allocations or memcpy operations.
>
> Cc: <stable@vger.kernel.org>
> Cc: Johannes Berg <johannes@sipsolutions.net>
> Cc: Kees Cook <keescook@chromium.org>
> Reported-by: Nicolas Waisman <nico@semmle.com>
> Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> net/mac80211/mlme.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index 26a2f49208b6..54dd8849d1cc 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -2633,7 +2633,8 @@ struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw,
>
> rcu_read_lock();
> ssid = ieee80211_bss_get_ie(cbss, WLAN_EID_SSID);
> - if (WARN_ON_ONCE(ssid == NULL))
> + if (WARN_ONCE(!ssid || ssid[1] > IEEE80211_MAX_SSID_LEN,
> + "invalid SSID element (len=%d)", ssid ? ssid[1] : -1))
> ssid_len = 0;
> else
> ssid_len = ssid[1];
> @@ -5233,7 +5234,7 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
>
> rcu_read_lock();
> ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID);
> - if (!ssidie) {
> + if (!ssidie || ssidie[1] > sizeof(assoc_data->ssid)) {
> rcu_read_unlock();
> kfree(assoc_data);
> return -EINVAL;
> --
> 2.23.0.581.g78d2f28ef7-goog
>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-04 15:56 UTC | newest]
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2019-10-04 9:51 [PATCH 1/2] mac80211: Reject malformed SSID elements Will Deacon
2019-10-04 9:51 ` [PATCH 2/2] cfg80211: wext: " Will Deacon
2019-10-04 15:56 ` Kees Cook
2019-10-04 15:55 ` [PATCH 1/2] mac80211: " Kees Cook
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