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 2CBD13A4525 for ; Mon, 9 Mar 2026 11:54:02 +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=1773057242; cv=none; b=j9D2myZ6lfOpmq+fPGvVZmGUXfHkQ9Xg0Efrp9WwMumM61RQa0Gr0YWBUippsFADVSA/DNct7xmdQXnz8bagmUHS4LZwJPut3+QFg6kgeXaG5G5x/mOUquBcNN/h//1HrMufOFoIDE3A+Jujzp2RQmLNa5ZLKug+gdRk1iQm1Go= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773057242; c=relaxed/simple; bh=X/+zob7ZhxaLHUNfCEjz1njTM6ff/CxwgbQ73QGxHqc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i8cYOgR22FgPgWoeKz1j6/82U4mnDw8syoZSsUJEDE9iOYRHUnPD5GdGgvR4BICtM5T2OeyePivZa44WZPMd70i9t6FHEEK04DY9dXE9MIncGjyaiLidlLbf/KFRd7Aeqbhjd6UEAxiSb4Gz7u+t1f5qNeuYZfmilowRk/s4XVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ed2VF7d4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ed2VF7d4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62536C4CEF7; Mon, 9 Mar 2026 11:54:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773057241; bh=X/+zob7ZhxaLHUNfCEjz1njTM6ff/CxwgbQ73QGxHqc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ed2VF7d4ONLygzS4rewr+6e7Gx10SBZbVs8v5rPOLwDfIbYdl9kWxQdq8qA4Eqyi1 ZfSFkjSpVgHXGDneZNhSLMX0A9ZifJj4wH+rViHSF3aWCHXJzJVmGTI2xRHlxZjFfb ZK0/JYAjq/y615/b01iv3g5ryemjOZcgakGSTOb2f5bCILa7SguIp7+bVi0bM+vMVh m0xUpFfUTgHWKTMrLPH602IapJc3CCtXJb44bXviSbmB4ZXv9r/dCBiCsEmzkcHMgq KJSaR6mJz5miFEa4Xr9dSt9brRPUV0KXdUfBtXOmq84AZnM3dfppONXTa7gb9qZEN/ hVyYAhTn/Nftg== From: Sasha Levin To: stable@vger.kernel.org Cc: Vahagn Vardanian , Johannes Berg , Sasha Levin Subject: [PATCH 5.10.y] wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame() Date: Mon, 9 Mar 2026 07:53:59 -0400 Message-ID: <20260309115359.840072-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2026030901-expensive-cosmetics-5a04@gregkh> References: <2026030901-expensive-cosmetics-5a04@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Vahagn Vardanian [ Upstream commit 017c1792525064a723971f0216e6ef86a8c7af11 ] 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 [ adapted pointer access elems-> to stack struct elems, and replaced goto free with return ] Signed-off-by: Sasha Levin --- net/mac80211/mesh.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index d3a9ce1f8e53f..20b8ff83e3dbd 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -1435,6 +1435,9 @@ static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata, if (!mesh_matches_local(sdata, &elems)) return; + if (!elems.mesh_chansw_params_ie) + return; + ifmsh->chsw_ttl = elems.mesh_chansw_params_ie->mesh_ttl; if (!--ifmsh->chsw_ttl) fwd_csa = false; -- 2.51.0