Date: Tue, 14 Aug 2018 20:24:11 +0000 (UTC) From: Cy Schubert <cy@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r337819 - head/contrib/wpa/src/rsn_supp Message-ID: <201808142024.w7EKOB4o011520@repo.freebsd.org>
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Author: cy Date: Tue Aug 14 20:24:10 2018 New Revision: 337819 URL: https://svnweb.freebsd.org/changeset/base/337819 Log: MFV r337818: 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> Obtained from: git://w1.fi/hostap.git MFC after: 1 day Security: CVE-2018-14526 Security: VuXML: 6bedc863-9fbe-11e8-945f-206a8a720317 Modified: head/contrib/wpa/src/rsn_supp/wpa.c Directory Properties: head/contrib/wpa/ (props changed) Modified: head/contrib/wpa/src/rsn_supp/wpa.c ============================================================================== --- head/contrib/wpa/src/rsn_supp/wpa.c Tue Aug 14 20:10:25 2018 (r337818) +++ head/contrib/wpa/src/rsn_supp/wpa.c Tue Aug 14 20:24:10 2018 (r337819) @@ -2072,6 +2072,17 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, const u8 *src_a if ((sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) && (key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) { + /* + * 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, ver, key_data, &key_data_len)) goto out;
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