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 DD8583A6B7F; Thu, 30 Jul 2026 14:21:33 +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=1785421298; cv=none; b=P2AnPKXihrQmq3lMf0OR+wfzobpWtIFrjVGS9Wht0zcVr0phaEc1jbqHyAmFTkJweGZDu9BeBu6kz/vH2YP7TRfYhYj6GWLmvaBhNy+ZuzwM83P26ir28g26E6LCAGsYRfb3pS+hCPiNdRHrAlm+hqPL7H54YMUfBTUvdXjgsB0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785421298; c=relaxed/simple; bh=bbi8vJj9re4tOV+L4T75WNdLw/MYXvao6yKNVtGd0M8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WU+OReEuHWmKVVQu7zB/RN7B/cYGiYi7pOalimlB5MxB8tx13kqwmPIlf2hiRLAsFoR3bm1vBbGvTTyNfM0whWX7en9hJgUzKT5b75Vhfg78luGeGV8vSuMFBXXhvXjXhffPfkbCESAMSIQ8PqiAc3KAslZbhMzHb6c47heOpxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ViZsJZuw; 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="ViZsJZuw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2D441F000E9; Thu, 30 Jul 2026 14:21:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785421293; bh=9tnkHgMz+YvF4vEUtl9xRcR6knd1kh7wP/qmixfCO/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ViZsJZuwjIcWgVReo2IBhFKYyX6aQfAQfIeNqrmlOFdT3/4Mi5F0LrZgJ1DJyy6A1 5XBEa+AKMUiYm3viWSsTlbRYyJRdw0DNwGbCX1Cb6YwU+Zvov1lONfqIZ7CKKweOtO 24Dx5dbaSTIOR1lsn1590+cfOSbSD598BRu9w7/Q= 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 7.1 055/744] wifi: mac80211: fix fils_discovery double free on alloc failure Date: Thu, 30 Jul 2026 16:05:28 +0200 Message-ID: <20260730141445.446924085@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141444.267951807@linuxfoundation.org> References: <20260730141444.267951807@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 7.1-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 e926bced6a313d..0bc10136b816ef 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -1145,9 +1145,6 @@ 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) @@ -1159,6 +1156,9 @@ 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