This is a note to let you know that I've just added the patch titled
wifi: mac80211: fix MBSSID parsing use-after-free
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
wifi-mac80211-fix-mbssid-parsing-use-after-free.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ff05d4b45dd89b922578dac497dcabf57cf771c6 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@xxxxxxxxx>
Date: Wed, 28 Sep 2022 22:07:15 +0200
Subject: wifi: mac80211: fix MBSSID parsing use-after-free
From: Johannes Berg <johannes.berg@xxxxxxxxx>
commit ff05d4b45dd89b922578dac497dcabf57cf771c6 upstream.
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@xxxxxxxxx>
Signed-off-by: Ilan Peer <ilan.peer@xxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mac80211/ieee80211_i.h | 8 ++++++++
net/mac80211/util.c | 28 ++++++++++++++--------------
2 files changed, 22 insertions(+), 14 deletions(-)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1704,6 +1704,14 @@ 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
@@ -1503,24 +1503,26 @@ ieee802_11_parse_elems_full(struct ieee8
const struct element *non_inherit = NULL;
u8 *nontransmitted_profile;
int nontransmitted_profile_len = 0;
+ size_t scratch_len = params->len;
- elems = kzalloc(sizeof(*elems), GFP_ATOMIC);
+ elems = kzalloc(sizeof(*elems) + scratch_len, GFP_ATOMIC);
if (!elems)
return NULL;
elems->ie_start = params->start;
elems->total_len = params->len;
+ elems->scratch_len = scratch_len;
+ elems->scratch_pos = elems->scratch;
- nontransmitted_profile = kmalloc(params->len, GFP_ATOMIC);
- if (nontransmitted_profile) {
- nontransmitted_profile_len =
- ieee802_11_find_bssid_profile(params->start, params->len,
- elems, params->bss,
- nontransmitted_profile);
- non_inherit =
- cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
- nontransmitted_profile,
- nontransmitted_profile_len);
- }
+ nontransmitted_profile = elems->scratch_pos;
+ nontransmitted_profile_len =
+ ieee802_11_find_bssid_profile(params->start, params->len,
+ elems, params->bss,
+ nontransmitted_profile);
+ elems->scratch_pos += nontransmitted_profile_len;
+ elems->scratch_len -= nontransmitted_profile_len;
+ non_inherit = cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
+ nontransmitted_profile,
+ nontransmitted_profile_len);
elems->crc = _ieee802_11_parse_elems_full(params, elems, non_inherit);
@@ -1554,8 +1556,6 @@ ieee802_11_parse_elems_full(struct ieee8
offsetofend(struct ieee80211_bssid_index, dtim_count))
elems->dtim_count = elems->bssid_index->dtim_count;
- kfree(nontransmitted_profile);
-
return elems;
}
Patches currently in stable-queue which might be from johannes.berg@xxxxxxxxx are
queue-6.0/wifi-mac80211-fix-crash-in-beacon-protection-for-p2p-device.patch
queue-6.0/wifi-cfg80211-avoid-nontransmitted-bss-list-corruption.patch
queue-6.0/wifi-cfg80211-mac80211-reject-bad-mbssid-elements.patch
queue-6.0/wifi-mac80211-fix-mbssid-parsing-use-after-free.patch
queue-6.0/wifi-cfg80211-ensure-length-byte-is-present-before-access.patch
queue-6.0/wifi-mac80211_hwsim-avoid-mac80211-warning-on-bad-rate.patch
queue-6.0/wifi-cfg80211-update-hidden-bsses-to-avoid-warn_on.patch
queue-6.0/wifi-cfg80211-fix-bss-refcounting-bugs.patch
queue-6.0/wifi-cfg80211-fix-u8-overflow-in-cfg80211_update_notlisted_nontrans.patch
