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44 lines
2.0 KiB
44 lines
2.0 KiB
From 3e34cfdff6b192fe337c6fb3f487f73e96582961 Mon Sep 17 00:00:00 2001 |
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From: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be> |
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Date: Sun, 15 Jul 2018 01:25:53 +0200 |
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Subject: [PATCH] WPA: Ignore unauthenticated encrypted EAPOL-Key data |
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Ignore unauthenticated encrypted EAPOL-Key data in supplicant |
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processing. When using WPA2, these are frames that have the Encrypted |
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flag set, but not the MIC flag. |
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When using WPA2, EAPOL-Key frames that had the Encrypted flag set but |
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not the MIC flag, had their data field decrypted without first verifying |
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the MIC. In case the data field was encrypted using RC4 (i.e., when |
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negotiating TKIP as the pairwise cipher), this meant that |
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unauthenticated but decrypted data would then be processed. An adversary |
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could abuse this as a decryption oracle to recover sensitive information |
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in the data field of EAPOL-Key messages (e.g., the group key). |
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(CVE-2018-14526) |
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Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@cs.kuleuven.be> |
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--- |
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src/rsn_supp/wpa.c | 11 +++++++++++ |
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1 file changed, 11 insertions(+) |
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diff -upr wpa_supplicant-2.6.orig/src/rsn_supp/wpa.c wpa_supplicant-2.6/src/rsn_supp/wpa.c |
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--- wpa_supplicant-2.6.orig/src/rsn_supp/wpa.c 2016-10-02 21:51:11.000000000 +0300 |
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+++ wpa_supplicant-2.6/src/rsn_supp/wpa.c 2018-08-08 16:55:11.506831029 +0300 |
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@@ -2016,6 +2016,17 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, c |
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if ((sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) && |
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(key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) { |
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+ /* |
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+ * Only decrypt the Key Data field if the frame's authenticity |
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+ * was verified. When using AES-SIV (FILS), the MIC flag is not |
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+ * set, so this check should only be performed if mic_len != 0 |
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+ * which is the case in this code branch. |
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+ */ |
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+ if (!(key_info & WPA_KEY_INFO_MIC)) { |
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+ wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, |
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+ "WPA: Ignore EAPOL-Key with encrypted but unauthenticated data"); |
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+ goto out; |
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+ } |
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if (wpa_supplicant_decrypt_key_data(sm, key, ver, key_data, |
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&key_data_len)) |
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goto out;
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