BACKPORT: cfg80211: wext: avoid copying malformed SSIDs
Ensure the SSID element is bounds-checked prior to invoking memcpy()
with its length field, when copying to userspace.
BUG=chromium:1031112
TEST=None
Cc: <stable@vger.kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Nicolas Waisman <nico@semmle.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20191004095132.15777-2-will@kernel.org
[adjust commit log a bit]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[backport: Apply patch to 3.8/4.2 wireless directories]
(cherry picked from commit 4ac2813cc867ae563a1ba5a9414bfb554e5796fa)
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Change-Id: I25fc6d81d1480af0eb2b7536b2ecf5021f1683f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1972291
Reviewed-by: Brian Norris <briannorris@chromium.org>
Commit-Queue: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Auto-Submit: Guenter Roeck <groeck@chromium.org>
diff --git a/net/wireless-3.8/wext-sme.c b/net/wireless-3.8/wext-sme.c
index fb9622f..c963270 100644
--- a/net/wireless-3.8/wext-sme.c
+++ b/net/wireless-3.8/wext-sme.c
@@ -233,6 +233,7 @@
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
+ int ret = 0;
/* call only for station! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION))
@@ -250,7 +251,10 @@
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) {
@@ -260,7 +264,7 @@
}
wdev_unlock(wdev);
- return 0;
+ return ret;
}
int cfg80211_mgd_wext_siwap(struct net_device *dev,
diff --git a/net/wireless-4.2/wext-sme.c b/net/wireless-4.2/wext-sme.c
index a4e8af3..98ff9d9 100644
--- a/net/wireless-4.2/wext-sme.c
+++ b/net/wireless-4.2/wext-sme.c
@@ -225,6 +225,7 @@
struct iw_point *data, char *ssid)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
+ int ret = 0;
/* call only for station! */
if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION))
@@ -242,7 +243,10 @@
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) {
@@ -252,7 +256,7 @@
}
wdev_unlock(wdev);
- return 0;
+ return ret;
}
int cfg80211_mgd_wext_siwap(struct net_device *dev,
