From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 22AE330C360; Mon, 13 Apr 2026 16:21:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097314; cv=none; b=NtKRy/7XqbZBLeTCZ+j5r/J0g303jrKCHfJkwoodLtKi9L0ZQmmx5ECAWuL1itUlE438Uy0IYDUjbNgCmgOWFFvYlR09Ct4sqHY7ybn26OELTCz236V26VGnvJLdScxy4/o4SVT0CC/Ks5CGyO3l9p9dfDZMB87ohI66Op0ZVbk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776097314; c=relaxed/simple; bh=Hg+GZLOnv5P+YcpG3nEi5WibgsTfgUzhqL30XF8hWQw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i93K/F5CQtLCvhtKzdDqcXVagEn0RLk/gRc9BXqg4w1ekJh5HtSWJdFPnHEhFfNYJKb8uvCdrOu3FxyNT1ZMk11c4tR41TkZLZmLyqndYo70j5JowHRgqPd2iXzEjSpLeYsQ80ysWW2xhOxy3ZaoeGLlZ0kddlvGb8gCqhNzd60= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pnBUA+BI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pnBUA+BI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC3F4C2BCB0; Mon, 13 Apr 2026 16:21:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776097314; bh=Hg+GZLOnv5P+YcpG3nEi5WibgsTfgUzhqL30XF8hWQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pnBUA+BI53qvx1/vK+qpZqNXCZ+GDK3FHU1G3gVbmKYAT84MssXqD1R1bXNDcdIdf KeGFSvo590xGv2gTHe4LdQZQnCTq/86Esr34NSBwh5JqG24wcwe82q77WON/YhMtPq mEOrtr1LA3AMwfzVrdu9ND2/w3+ny6zvBaEJd7lY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vahagn Vardanian , Johannes Berg Subject: [PATCH 5.15 056/570] wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame() Date: Mon, 13 Apr 2026 17:53:07 +0200 Message-ID: <20260413155832.540264249@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155830.386096114@linuxfoundation.org> References: <20260413155830.386096114@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vahagn Vardanian commit 017c1792525064a723971f0216e6ef86a8c7af11 upstream. In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced at lines 1638 and 1642 without a prior NULL check: ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl; ... pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value); The mesh_matches_local() check above only validates the Mesh ID, Mesh Configuration, and Supported Rates IEs. It does not verify the presence of the Mesh Channel Switch Parameters IE (element ID 118). When a received CSA action frame omits that IE, ieee802_11_parse_elems() leaves elems->mesh_chansw_params_ie as NULL, and the unconditional dereference causes a kernel NULL pointer dereference. A remote mesh peer with an established peer link (PLINK_ESTAB) can trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame that includes a matching Mesh ID and Mesh Configuration IE but omits the Mesh Channel Switch Parameters IE. No authentication beyond the default open mesh peering is required. Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim: BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211] CR2: 0000000000000000 Fix by adding a NULL check for mesh_chansw_params_ie after mesh_matches_local() returns, consistent with how other optional IEs are guarded throughout the mesh code. The bug has been present since v3.13 (released 2014-01-19). Fixes: 8f2535b92d68 ("mac80211: process the CSA frame for mesh accordingly") Cc: stable@vger.kernel.org Signed-off-by: Vahagn Vardanian Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/mesh.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -1477,6 +1477,9 @@ static void mesh_rx_csa_frame(struct iee if (!mesh_matches_local(sdata, elems)) goto free; + if (!elems->mesh_chansw_params_ie) + goto free; + ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl; if (!--ifmsh->chsw_ttl) fwd_csa = false;