| wpa_supplicant-2.6: Fix CVE-2018-14526 |
| |
| [No upstream tracking] -- https://w1.fi/security/2018-1/unauthenticated-eapol-key-decryption.txt |
| |
| 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). |
| |
| Upstream-Status: Backport [https://w1.fi/cgit/hostap/commit/src/rsn_supp/wpa.c?id=3e34cfdff6b192fe337c6fb3f487f73e96582961] |
| CVE: CVE-2018-14526 |
| Signed-off-by: Andrej Valek <andrej.valek@siemens.com> |
| |
| diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c |
| index 3c47879..6bdf923 100644 |
| --- a/src/rsn_supp/wpa.c |
| +++ b/src/rsn_supp/wpa.c |
| @@ -2016,6 +2016,17 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, const u8 *src_addr, |
| |
| 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; |