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- From 3e34cfdff6b192fe337c6fb3f487f73e96582961 Mon Sep 17 00:00:00 2001
- From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
- Date: Sun, 15 Jul 2018 01:25:53 +0200
- Subject: [PATCH] WPA: Ignore unauthenticated encrypted EAPOL-Key data
- Ignore unauthenticated encrypted EAPOL-Key data in supplicant
- processing. When using WPA2, these are frames that have the Encrypted
- flag set, but not the MIC flag.
- When using WPA2, EAPOL-Key frames that had the Encrypted flag set but
- not the MIC flag, had their data field decrypted without first verifying
- the MIC. In case the data field was encrypted using RC4 (i.e., when
- negotiating TKIP as the pairwise cipher), this meant that
- unauthenticated but decrypted data would then be processed. An adversary
- could abuse this as a decryption oracle to recover sensitive information
- in the data field of EAPOL-Key messages (e.g., the group key).
- (CVE-2018-14526)
- Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be>
- ---
- src/rsn_supp/wpa.c | 11 +++++++++++
- 1 file changed, 11 insertions(+)
- --- a/src/rsn_supp/wpa.c
- +++ b/src/rsn_supp/wpa.c
- @@ -2157,6 +2157,17 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, c
-
- if ((sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) &&
- (key_info & WPA_KEY_INFO_ENCR_KEY_DATA) && mic_len) {
- + /*
- + * Only decrypt the Key Data field if the frame's authenticity
- + * was verified. When using AES-SIV (FILS), the MIC flag is not
- + * set, so this check should only be performed if mic_len != 0
- + * which is the case in this code branch.
- + */
- + if (!(key_info & WPA_KEY_INFO_MIC)) {
- + wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
- + "WPA: Ignore EAPOL-Key with encrypted but unauthenticated data");
- + goto out;
- + }
- if (wpa_supplicant_decrypt_key_data(sm, key, mic_len,
- ver, key_data,
- &key_data_len))
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