cfg80211: allow wext to remove keys that don't exist

Some applications using wireless extensions expect to be able to
remove a key that doesn't exist. One example is wpa_supplicant
which doesn't actually change behaviour when running into an
error while trying to do that, but it prints an error message
which users interpret as wpa_supplicant having problems.

The safe thing to do is not change the behaviour of wireless
extensions any more, so when the driver reports -ENOENT let
the wext bridge code return success to userspace. To guarantee
this, also document that drivers should return -ENOENT when the
key doesn't exist.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 10 insertions, 2 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 81a3bfa45471..389f1d20adf4 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -781,10 +781,11 @@ enum wiphy_params_flags {
  * @get_key: get information about the key with the given parameters.
  *      @mac_addr will be %NULL when requesting information for a group
  *      key. All pointers given to the @callback function need not be valid
- *      after it returns.
+ *      after it returns. This function should return an error if it is
+ *      not possible to retrieve the key, -ENOENT if it doesn't exist.
  *
  * @del_key: remove a key given the @mac_addr (%NULL for a group key)
- *      and @key_index
+ *      and @key_index, return -ENOENT if the key doesn't exist.
  *
  * @set_default_key: set the default key on an interface
  *
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index f98090b90fbf..711e00a0c9b5 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -504,6 +504,13 @@ static int cfg80211_set_encryption(struct cfg80211_registered_device *rdev,
                         else if (idx == wdev->wext.default_mgmt_key)
                                 wdev->wext.default_mgmt_key = -1;
                 }
+                /*
+                 * Applications using wireless extensions expect to be
+                 * able to delete keys that don't exist, so allow that.
+                 */
+                if (err == -ENOENT)
+                        return 0;
+
                 return err;
         } else {
                 if (addr)