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Commit e3a55b53 authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: validate cipher scheme PN length better 



Currently, a cipher scheme can advertise an arbitrarily long
sequence counter, but mac80211 only supports up to 16 bytes
and the initial value from userspace will be truncated.

Fix two things:
 * don't allow the driver to register anything longer than
   the 16 bytes that mac80211 reserves space for
 * require userspace to specify a starting value with the
   correct length (or none at all)

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent a31cf1c6

net/mac80211/key.c

+6 −4
Original line number Diff line number Diff line
@@ -485,15 +485,17 @@ ieee80211_key_alloc(u32 cipher, int idx, size_t key_len, 
		break;

	default:

		if (cs) {

			size_t len = (seq_len > IEEE80211_MAX_PN_LEN) ?

						IEEE80211_MAX_PN_LEN : seq_len;

			if (seq_len && seq_len != cs->pn_len) {

				kfree(key);

				return ERR_PTR(-EINVAL);

			}



			key->conf.iv_len = cs->hdr_len;

			key->conf.icv_len = cs->mic_len;

			for (i = 0; i < IEEE80211_NUM_TIDS + 1; i++)

				for (j = 0; j < len; j++)

				for (j = 0; j < seq_len; j++)

					key->u.gen.rx_pn[i][j] =

							seq[len - j - 1];

							seq[seq_len - j - 1];

			key->flags |= KEY_FLAG_CIPHER_SCHEME;

		}

	}

net/mac80211/main.c

+4 −1
Original line number Diff line number Diff line
@@ -768,8 +768,11 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local) 
			suites[w++] = WLAN_CIPHER_SUITE_BIP_GMAC_256;

		}



		for (r = 0; r < local->hw.n_cipher_schemes; r++)

		for (r = 0; r < local->hw.n_cipher_schemes; r++) {

			suites[w++] = cs[r].cipher;

			if (WARN_ON(cs[r].pn_len > IEEE80211_MAX_PN_LEN))

				return -EINVAL;

		}

	}



	local->hw.wiphy->cipher_suites = suites;