Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E29DC678D5 for ; Wed, 8 Mar 2023 09:10:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229803AbjCHJKD (ORCPT ); Wed, 8 Mar 2023 04:10:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230445AbjCHJJ4 (ORCPT ); Wed, 8 Mar 2023 04:09:56 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AE28BB9B for ; Wed, 8 Mar 2023 01:09:55 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 380CEB81A3C for ; Wed, 8 Mar 2023 09:09:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EB80C4339B; Wed, 8 Mar 2023 09:09:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678266593; bh=Di8+VgrUoxorOJabFpFCQfSfT+1t6oSErezqd0MbWaM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NTyTcDN+ruhmS7DQr3k64P8xkFeceFBcqIvw88/BHshMBU2LwSViNb3Q7TyeZQWrF TThN/jaeAJObf0N1cfr4VDqJ3pyvkP1pF1OGc20xS5baAiSm2tn3U9anHAD0YfOPzo aPknhZg4OX+k0EvQuNvObMQtTkSEUSQRDcSPJYlbOMA8NQcoQmDVHKE0Hi+UNj0tmV JNA9FKMI2ZiejCCU6g5T8/0GP0Zgth/Wo4qe0wZGwF4ssIUvJngacsn+hNcHmEr1KM pVuMaVMala4N2tc7u85Qe3prKiKI7YYOtJhc7FKG35Mc+fsl4F1PQjdMawB3NQErku CNCCgh3P+Mtvg== Date: Wed, 8 Mar 2023 10:09:49 +0100 From: Lorenzo Bianconi To: greearb@candelatech.com Cc: linux-wireless@vger.kernel.org Subject: Re: [PATCH] wireless: mt76: mt7921: Fix use-after-free in fw features query. Message-ID: References: <20230308010026.2206775-1-greearb@candelatech.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="WY5RmKBgtsjfMk4X" Content-Disposition: inline In-Reply-To: <20230308010026.2206775-1-greearb@candelatech.com> Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org --WY5RmKBgtsjfMk4X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > From: Ben Greear >=20 > Stop referencing 'features' memory after release_firmware is called. >=20 > Fixes this crash: >=20 > RIP: 0010:mt7921_check_offload_capability+0x17d > mt7921_pci_probe+0xca/0x4b0 Hi Ben, thx for fixing it. Just few minor comments inline. Regards, Lorenzo > ... >=20 > Signed-off-by: Ben Greear > --- > drivers/net/wireless/mediatek/mt76/mt7921/init.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) >=20 > diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/init.c b/drivers/n= et/wireless/mediatek/mt76/mt7921/init.c > index 38d6563cb12f..3b6fb1a6b351 100644 > --- a/drivers/net/wireless/mediatek/mt76/mt7921/init.c > +++ b/drivers/net/wireless/mediatek/mt76/mt7921/init.c > @@ -171,6 +171,7 @@ u8 mt7921_check_offload_capability(struct device *dev= , const char *fw_wm) > const struct firmware *fw; > int ret, i, offset =3D 0; > const u8 *data, *end; > + u8 rv =3D 0; I would say we can use a more meaningful name here, something like offload_= capa or similar. Moreover I thin you can move features pointer just in the if (rel_info->tag =3D=3D MT7921_FW_TAG_FEATURE) block. Regards, Lorenzo > =20 > ret =3D request_firmware(&fw, fw_wm, dev); > if (ret) > @@ -197,12 +198,17 @@ u8 mt7921_check_offload_capability(struct device *d= ev, const char *fw_wm) > data +=3D sizeof(*rel_info); > end =3D data + le16_to_cpu(rel_info->len); > =20 > + /* TODO: This needs better sanity checking I think. > + * Likely a corrupted firmware with bad rel_info->len, for instance, > + * would blow this up. > + */ > while (data < end) { > rel_info =3D (struct mt7921_realease_info *)data; > data +=3D sizeof(*rel_info); > =20 > if (rel_info->tag =3D=3D MT7921_FW_TAG_FEATURE) { > features =3D (struct mt7921_fw_features *)data; > + rv =3D features->data; > break; > } > =20 > @@ -211,7 +217,7 @@ u8 mt7921_check_offload_capability(struct device *dev= , const char *fw_wm) > =20 > release_firmware(fw); > =20 > - return features ? features->data : 0; > + return rv; > } > EXPORT_SYMBOL_GPL(mt7921_check_offload_capability); > =20 > --=20 > 2.39.1 >=20 --WY5RmKBgtsjfMk4X Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCZAhQ3AAKCRA6cBh0uS2t rJG+AQChksnGL8H+S9h840ygnl/xprT/fTT2iJ7VYKQcCLRkMAD/Sudu2zranQbX 0g/l2FoFVIsL54ehCppLQqZOuuoWNgU= =DhpN -----END PGP SIGNATURE----- --WY5RmKBgtsjfMk4X--