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[SRU,Hirsute,Groovy,Focal/linux-oem-5.10,Focal/linux-oem-5.6,Focal,05/16] mac80211: prevent attacks on TKIP/WEP as well

Message ID 20210525174625.69071-7-cascardo@canonical.com
State Accepted
Headers show
Series [SRU,Hirsute,Groovy,Focal/linux-oem-5.10,Focal/linux-oem-5.6,Focal,01/16] mac80211: assure all fragments are encrypted | expand

Commit Message

Thadeu Lima de Souza Cascardo May 25, 2021, 5:46 p.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

Similar to the issues fixed in previous patches, TKIP and WEP
should be protected even if for TKIP we have the Michael MIC
protecting it, and WEP is broken anyway.

However, this also somewhat protects potential other algorithms
that drivers might implement.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.430e8c202313.Ia37e4e5b6b3eaab1a5ae050e015f6c92859dbe27@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
(cherry picked from commit 7e44a0b597f04e67eee8cdcbe7ee706c6f5de38b)
CVE-2020-24586
CVE-2020-24587
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
---
 net/mac80211/rx.c       | 12 ++++++++++++
 net/mac80211/sta_info.h |  3 ++-
 2 files changed, 14 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 1e2627889f17..fb7981c42a82 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2273,6 +2273,7 @@  ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 			 * next fragment has a sequential PN value.
 			 */
 			entry->check_sequential_pn = true;
+			entry->is_protected = true;
 			entry->key_color = rx->key->color;
 			memcpy(entry->last_pn,
 			       rx->key->u.ccmp.rx_pn[queue],
@@ -2285,6 +2286,9 @@  ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 				     sizeof(rx->key->u.gcmp.rx_pn[queue]));
 			BUILD_BUG_ON(IEEE80211_CCMP_PN_LEN !=
 				     IEEE80211_GCMP_PN_LEN);
+		} else if (rx->key && ieee80211_has_protected(fc)) {
+			entry->is_protected = true;
+			entry->key_color = rx->key->color;
 		}
 		return RX_QUEUED;
 	}
@@ -2326,6 +2330,14 @@  ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 		if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN))
 			return RX_DROP_UNUSABLE;
 		memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN);
+	} else if (entry->is_protected &&
+		   (!rx->key || !ieee80211_has_protected(fc) ||
+		    rx->key->color != entry->key_color)) {
+		/* Drop this as a mixed key or fragment cache attack, even
+		 * if for TKIP Michael MIC should protect us, and WEP is a
+		 * lost cause anyway.
+		 */
+		return RX_DROP_UNUSABLE;
 	}
 
 	skb_pull(rx->skb, ieee80211_hdrlen(fc));
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 7d4f798458d6..355e006432cc 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -453,7 +453,8 @@  struct ieee80211_fragment_entry {
 	u16 extra_len;
 	u16 last_frag;
 	u8 rx_queue;
-	bool check_sequential_pn; /* needed for CCMP/GCMP */
+	u8 check_sequential_pn:1, /* needed for CCMP/GCMP */
+	   is_protected:1;
 	u8 last_pn[6]; /* PN of the last fragment if CCMP was used */
 	unsigned int key_color;
 };