From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3EC7F43C7C5; Thu, 30 Jul 2026 14:58:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423519; cv=none; b=TG/rhXf/dDUEI3O8zlj6bRx8tgesDrYrFNm7NkItDu1HJWwGQUjYsPvtIQO/0EapWNEkMpxfjetbOXm4QlxBQQpCs2yYNZHBKFBJlapAelBquXlAT/ng/TzWoR5d0zKg4gt5Xf3dfzywH3aRKd3Als3merSuEfHHSGBsMm8wgks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423519; c=relaxed/simple; bh=5GjxdqToSJOV4Q5+dE7jvz97Ix/qoHlqPxH40pMNzoM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vi5KhKXdvFDtZs/6jDzAOGnQ5Y5HqMPt8T0H8zHPO6aT3FMSdJiUFGmsKNn9JXN7UEtmW2N1H6rvF6WBHRNAN5au4ov7o/F+3Wx8oMUaUE1dsD3ILEQxW/gOS9vHMS1E0OjqzHR6WDcKWWhDihptMNBtnlMn5X93a1/qBb5HbR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UjBVbyk/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UjBVbyk/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70A7F1F000E9; Thu, 30 Jul 2026 14:58:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785423518; bh=sJJoLnYS2gaZm+/u10zRBuSg2cLcSAzZ0008NqxIBUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UjBVbyk/4CleLp8EvecNnPdIpWbAQQixGzAOPQMqR+xalr/YfAs1BOIgsQLMZ7CzT 6ZhIvFAXIiMSjUPclFOyZdSUL9uto62A+ZJH2wiI+BC3Bhel0CSjJtqQmk9cAIFXw1 0m+5Ca7F1P2BbSdNNBMuOhz99Ej9W9nqOV+Mwf/I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Johannes Berg , Sasha Levin Subject: [PATCH 6.18 070/675] wifi: mac80211: fix fils_discovery double free on alloc failure Date: Thu, 30 Jul 2026 16:06:40 +0200 Message-ID: <20260730141446.616369273@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 286e52a799fa158bdbd77da1426c4d93f9a6e7ad ] ieee80211_set_fils_discovery() calls kfree_rcu() on the old template before allocating the replacement. If the kzalloc() then fails, it returns -ENOMEM while link->u.ap.fils_discovery still points at the object already queued for freeing. A later update or AP teardown (ieee80211_stop_ap()) re-queues that same rcu_head; the second free is caught by KASAN when the RCU sheaf is processed in softirq: BUG: KASAN: double-free in rcu_free_sheaf (mm/slub.c:5850) Free of addr ffff88800c065280 by task swapper/0/0 ... __rcu_free_sheaf_prepare (mm/slub.c:2634 mm/slub.c:2940) rcu_free_sheaf (mm/slub.c:5850) rcu_core (kernel/rcu/tree.c:2617 kernel/rcu/tree.c:2869) handle_softirqs (kernel/softirq.c:622) The buggy address belongs to the cache kmalloc-96 of size 96 Queue the old object for kfree_rcu() only after the new one is published, matching ieee80211_set_probe_resp() and ieee80211_set_s1g_short_beacon(). Fixes: 3b1c256eb4ae ("wifi: mac80211: fixes in FILS discovery updates") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Link: https://patch.msgid.link/20260621093532.884188-2-xmei5@asu.edu Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/cfg.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 001e4bb55b6199..f6232948bc0f4a 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -1124,9 +1124,6 @@ static int ieee80211_set_fils_discovery(struct ieee80211_sub_if_data *sdata, fd->max_interval = params->max_interval; old = sdata_dereference(link->u.ap.fils_discovery, sdata); - if (old) - kfree_rcu(old, rcu_head); - if (params->tmpl && params->tmpl_len) { new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL); if (!new) @@ -1138,6 +1135,9 @@ static int ieee80211_set_fils_discovery(struct ieee80211_sub_if_data *sdata, RCU_INIT_POINTER(link->u.ap.fils_discovery, NULL); } + if (old) + kfree_rcu(old, rcu_head); + *changed |= BSS_CHANGED_FILS_DISCOVERY; return 0; } -- 2.53.0