openwrt/package/kernel/mac80211/patches/subsys/353-wifi-mac80211-fix-MBSSID-parsing-use-after-free.patch
Felix Fietkau 26f400210d mac80211: backport security fixes
This mainly affects scanning and beacon parsing, especially with MBSSID enabled

Fixes: CVE-2022-41674
Fixes: CVE-2022-42719
Fixes: CVE-2022-42720
Fixes: CVE-2022-42721
Fixes: CVE-2022-42722
Signed-off-by: Felix Fietkau <nbd@nbd.name>
2022-10-13 15:00:59 +02:00

95 lines
3.0 KiB
Diff

From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 28 Sep 2022 22:07:15 +0200
Subject: [PATCH] wifi: mac80211: fix MBSSID parsing use-after-free
commit ff05d4b45dd89b922578dac497dcabf57cf771c6
When we parse a multi-BSSID element, we might point some
element pointers into the allocated nontransmitted_profile.
However, we free this before returning, causing UAF when the
relevant pointers in the parsed elements are accessed.
Fix this by not allocating the scratch buffer separately but
as part of the returned structure instead, that way, there
are no lifetime issues with it.
The scratch buffer introduction as part of the returned data
here is taken from MLO feature work done by Ilan.
This fixes CVE-2022-42719.
Fixes: 5023b14cf4df ("mac80211: support profile split between elements")
Co-developed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1611,6 +1611,14 @@ struct ieee802_11_elems {
/* whether a parse error occurred while retrieving these elements */
bool parse_error;
+
+ /*
+ * scratch buffer that can be used for various element parsing related
+ * tasks, e.g., element de-fragmentation etc.
+ */
+ size_t scratch_len;
+ u8 *scratch_pos;
+ u8 scratch[];
};
static inline struct ieee80211_local *hw_to_local(
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1478,24 +1478,25 @@ struct ieee802_11_elems *ieee802_11_pars
u8 *nontransmitted_profile;
int nontransmitted_profile_len = 0;
- elems = kzalloc(sizeof(*elems), GFP_ATOMIC);
+ elems = kzalloc(sizeof(*elems) + len, GFP_ATOMIC);
if (!elems)
return NULL;
elems->ie_start = start;
elems->total_len = len;
- nontransmitted_profile = kmalloc(len, GFP_ATOMIC);
- if (nontransmitted_profile) {
- nontransmitted_profile_len =
- ieee802_11_find_bssid_profile(start, len, elems,
- transmitter_bssid,
- bss_bssid,
- nontransmitted_profile);
- non_inherit =
- cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
- nontransmitted_profile,
- nontransmitted_profile_len);
- }
+ elems->scratch_len = len;
+ elems->scratch_pos = elems->scratch;
+
+ nontransmitted_profile = elems->scratch_pos;
+ nontransmitted_profile_len =
+ ieee802_11_find_bssid_profile(start, len, elems,
+ transmitter_bssid,
+ bss_bssid,
+ nontransmitted_profile);
+ non_inherit =
+ cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
+ nontransmitted_profile,
+ nontransmitted_profile_len);
crc = _ieee802_11_parse_elems_crc(start, len, action, elems, filter,
crc, non_inherit);
@@ -1524,8 +1525,6 @@ struct ieee802_11_elems *ieee802_11_pars
offsetofend(struct ieee80211_bssid_index, dtim_count))
elems->dtim_count = elems->bssid_index->dtim_count;
- kfree(nontransmitted_profile);
-
elems->crc = crc;
return elems;