6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhiling Zou [ Upstream commit 437f3727b4fd715266c296435c116288f82666fd ] ieee80211_vif_use_reserved_switch() validates a replacement by counting assigned links on ctx->replace_ctx and treating reservations too broadly. A link can still be assigned to the old channel context while holding a reservation that belongs to a different replacement operation. That can make the current replacement appear complete too early. If another link finalizes first, the function can free the WILL_BE_REPLACED chanctx while the unmatched link and driver still use it, leading to a use-after-free in later beacon generation. Require an in-place reservation to point at the current replacement context, and require the reserved and assigned contexts to be the matching replacement pair, before counting or moving the link. Fixes: 5bcae31d9cb1 ("mac80211: implement multi-vif in-place reservations") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Link: https://patch.msgid.link/4b6c4b8648ab1920c38a40be32c0b1a2797b4ac6.1785726007.git.zhilinz@nebusec.ai Signed-off-by: Johannes Berg [ sashal: Adapted channel-context iterators to direct link-list traversal. ] Signed-off-by: Sasha Levin --- net/mac80211/chan.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 85875ed7536f8..29a6ad65c9a8b 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -1394,7 +1394,8 @@ ieee80211_link_use_reserved_assign(struct ieee80211_link_data *link) } static bool -ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link) +ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link, + struct ieee80211_chanctx *ctx) { struct ieee80211_sub_if_data *sdata = link->sdata; struct ieee80211_chanctx *old_ctx, *new_ctx; @@ -1404,6 +1405,9 @@ ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link) new_ctx = link->reserved_chanctx; old_ctx = ieee80211_link_get_chanctx(link); + if (new_ctx != ctx) + return false; + if (!old_ctx) return false; @@ -1416,6 +1420,12 @@ ieee80211_link_has_in_place_reservation(struct ieee80211_link_data *link) if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER) return false; + if (new_ctx->replace_ctx != old_ctx) + return false; + + if (old_ctx->replace_ctx != new_ctx) + return false; + return true; } @@ -1465,7 +1475,7 @@ static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local, list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list) { - if (!ieee80211_link_has_in_place_reservation(link)) + if (!ieee80211_link_has_in_place_reservation(link, ctx)) continue; old_ctx = ieee80211_link_get_chanctx(link); @@ -1574,7 +1584,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local) list_for_each_entry(link, &ctx->replace_ctx->assigned_links, assigned_chanctx_list) { n_assigned++; - if (link->reserved_chanctx) { + if (ieee80211_link_has_in_place_reservation(link, ctx)) { n_reserved++; if (link->reserved_ready) n_ready++; @@ -1595,7 +1605,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local) ctx->conf.radar_enabled = false; list_for_each_entry(link, &ctx->reserved_links, reserved_chanctx_list) { - if (ieee80211_link_has_in_place_reservation(link) && + if (ieee80211_link_has_in_place_reservation(link, ctx) && !link->reserved_ready) return -EAGAIN; @@ -1669,7 +1679,7 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local) struct ieee80211_bss_conf *link_conf = link->conf; u64 changed = 0; - if (!ieee80211_link_has_in_place_reservation(link)) + if (!ieee80211_link_has_in_place_reservation(link, ctx)) continue; rcu_assign_pointer(link_conf->chanctx_conf, @@ -1722,7 +1732,8 @@ static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local) */ list_for_each_entry_safe(link, link_tmp, &ctx->reserved_links, reserved_chanctx_list) { - if (WARN_ON(ieee80211_link_has_in_place_reservation(link))) + if (WARN_ON(ieee80211_link_has_in_place_reservation(link, + ctx))) continue; if (WARN_ON(link->reserved_chanctx != ctx)) -- 2.53.0