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 30BE92D9ECB; Mon, 23 Mar 2026 14:56:37 +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=1774277797; cv=none; b=tHZbFQCmtCdBepa2BmAvUuMU0n9WPfFD1WUBYGRymYzfimGoR1Ayo7tRxXbLFwx+lkvVlbqlwIKhR4daIiDJD+xVpZdfOxJhI4BtvfE5ssILVQQ3UoF5gyncQrsQOam1cbmmzgIR5ftjkELWue0eBhOQLXGeVs5ugDPzJybrbLo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774277797; c=relaxed/simple; bh=gajc+07gG6oG12zuhw4AjAQG1PhO2Jb0bIWiQGl3xiw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZdBysNstnoU6PJB+OrMoiF3T3Y6QTD+ABWbW3NPlDVMcOTJYULmGMS3HKwC0rueg4zXtlZvlzLj7cF1nBiJ/E6QmKbgO1yYGfRRPEBapPre8RFvi+gQsGmKmYEfcB6qy4mwOI2pxOcUP2zqtbN0RLUcQnOv+Mrc9zF9yZt6PC8k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tLJyLfH3; 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="tLJyLfH3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A97A2C4CEF7; Mon, 23 Mar 2026 14:56:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774277797; bh=gajc+07gG6oG12zuhw4AjAQG1PhO2Jb0bIWiQGl3xiw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tLJyLfH3oDkfxtPdg1fz3JupOdvjG/44DpWVTpt3Wij201ffVAKJC5OAegLSAj1h/ C7APv+TMfQr+1Av1zglIUpuwS/7jaO1D03TDpBP+1Lb8qPxO+wfF5r1UODNwzsPi2r oKfxeNSY3whWUU2w2tpQLh+981kjY4Owcn0S6oAA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vahagn Vardanian , Johannes Berg Subject: [PATCH 6.6 107/567] wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame() Date: Mon, 23 Mar 2026 14:40:27 +0100 Message-ID: <20260323134536.467153543@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134533.749096647@linuxfoundation.org> References: <20260323134533.749096647@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 6.6-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 @@ -1640,6 +1640,9 @@ 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;