The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2d9463083ce92636a1bdd3e30d1236e3e95d859e Mon Sep 17 00:00:00 2001
From: Anant Thazhemadam anant.thazhemadam@gmail.com Date: Sat, 5 Dec 2020 03:28:25 +0530 Subject: [PATCH] nl80211: validate key indexes for cfg80211_registered_device
syzbot discovered a bug in which an OOB access was being made because an unsuitable key_idx value was wrongly considered to be acceptable while deleting a key in nl80211_del_key().
Since we don't know the cipher at the time of deletion, if cfg80211_validate_key_settings() were to be called directly in nl80211_del_key(), even valid keys would be wrongly determined invalid, and deletion wouldn't occur correctly. For this reason, a new function - cfg80211_valid_key_idx(), has been created, to determine if the key_idx value provided is valid or not. cfg80211_valid_key_idx() is directly called in 2 places - nl80211_del_key(), and cfg80211_validate_key_settings().
Reported-by: syzbot+49d4cab497c2142ee170@syzkaller.appspotmail.com Tested-by: syzbot+49d4cab497c2142ee170@syzkaller.appspotmail.com Suggested-by: Johannes Berg johannes@sipsolutions.net Signed-off-by: Anant Thazhemadam anant.thazhemadam@gmail.com Link: https://lore.kernel.org/r/20201204215825.129879-1-anant.thazhemadam@gmail.co... Cc: stable@vger.kernel.org [also disallow IGTK key IDs if no IGTK cipher is supported] Signed-off-by: Johannes Berg johannes.berg@intel.com
diff --git a/net/wireless/core.h b/net/wireless/core.h index e3e9686859d4..7df91f940212 100644 --- a/net/wireless/core.h +++ b/net/wireless/core.h @@ -433,6 +433,8 @@ void cfg80211_sme_abandon_assoc(struct wireless_dev *wdev);
/* internal helpers */ bool cfg80211_supported_cipher_suite(struct wiphy *wiphy, u32 cipher); +bool cfg80211_valid_key_idx(struct cfg80211_registered_device *rdev, + int key_idx, bool pairwise); int cfg80211_validate_key_settings(struct cfg80211_registered_device *rdev, struct key_params *params, int key_idx, bool pairwise, const u8 *mac_addr); diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index c8d31181a660..910872974f2d 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -4239,9 +4239,6 @@ static int nl80211_del_key(struct sk_buff *skb, struct genl_info *info) if (err) return err;
- if (key.idx < 0) - return -EINVAL; - if (info->attrs[NL80211_ATTR_MAC]) mac_addr = nla_data(info->attrs[NL80211_ATTR_MAC]);
@@ -4257,6 +4254,10 @@ static int nl80211_del_key(struct sk_buff *skb, struct genl_info *info) key.type != NL80211_KEYTYPE_GROUP) return -EINVAL;
+ if (!cfg80211_valid_key_idx(rdev, key.idx, + key.type == NL80211_KEYTYPE_PAIRWISE)) + return -EINVAL; + if (!rdev->ops->del_key) return -EOPNOTSUPP;
diff --git a/net/wireless/util.c b/net/wireless/util.c index 79c5780e3033..b4acc805114b 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -272,18 +272,53 @@ bool cfg80211_supported_cipher_suite(struct wiphy *wiphy, u32 cipher) return false; }
-int cfg80211_validate_key_settings(struct cfg80211_registered_device *rdev, - struct key_params *params, int key_idx, - bool pairwise, const u8 *mac_addr) +static bool +cfg80211_igtk_cipher_supported(struct cfg80211_registered_device *rdev) { - int max_key_idx = 5; + struct wiphy *wiphy = &rdev->wiphy; + int i; + + for (i = 0; i < wiphy->n_cipher_suites; i++) { + switch (wiphy->cipher_suites[i]) { + case WLAN_CIPHER_SUITE_AES_CMAC: + case WLAN_CIPHER_SUITE_BIP_CMAC_256: + case WLAN_CIPHER_SUITE_BIP_GMAC_128: + case WLAN_CIPHER_SUITE_BIP_GMAC_256: + return true; + } + } + + return false; +}
- if (wiphy_ext_feature_isset(&rdev->wiphy, - NL80211_EXT_FEATURE_BEACON_PROTECTION) || - wiphy_ext_feature_isset(&rdev->wiphy, - NL80211_EXT_FEATURE_BEACON_PROTECTION_CLIENT)) +bool cfg80211_valid_key_idx(struct cfg80211_registered_device *rdev, + int key_idx, bool pairwise) +{ + int max_key_idx; + + if (pairwise) + max_key_idx = 3; + else if (wiphy_ext_feature_isset(&rdev->wiphy, + NL80211_EXT_FEATURE_BEACON_PROTECTION) || + wiphy_ext_feature_isset(&rdev->wiphy, + NL80211_EXT_FEATURE_BEACON_PROTECTION_CLIENT)) max_key_idx = 7; + else if (cfg80211_igtk_cipher_supported(rdev)) + max_key_idx = 5; + else + max_key_idx = 3; + if (key_idx < 0 || key_idx > max_key_idx) + return false; + + return true; +} + +int cfg80211_validate_key_settings(struct cfg80211_registered_device *rdev, + struct key_params *params, int key_idx, + bool pairwise, const u8 *mac_addr) +{ + if (!cfg80211_valid_key_idx(rdev, key_idx, pairwise)) return -EINVAL;
if (!pairwise && mac_addr && !(rdev->wiphy.flags & WIPHY_FLAG_IBSS_RSN))