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 B2C29201032 for ; Wed, 10 Sep 2025 15:21:43 +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=1757517703; cv=none; b=EULYzzZhsADyUdh8wNzywr3FUrkOKETvMl917VYcjf9yJP/BKTdAAlTUIkEXgT7ItwMpLzFIQJaWtqz+Hyq+M85hC6az2Ksjiqpod+2UbBJywk/7/aszKkC3zNBuM/7ZT50ZAeNQvhXxQnTenAyXNqqlV6Vi/fH1bOKVA5vXPec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757517703; c=relaxed/simple; bh=9o0F2OBlrU7QKpOKRU9f0MYopKj2fo8G1bITsYXyof0=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=YwwM/AH+g9fTNeypVQTWJwz1GJU8pgNU5tpa1zsrW+bxqvsyiF8AREEwbrGu/+T6Q+vI+mFMp4C8m/Vw+AOqgFVv8/4oeJYioBX9QPYHtaODue0vrrBLjcnrpxGCkuHfG637Mz7PiOE5jam0cN9O6GcfztDxphcqCc7+Pn+6Qlw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Yd8S3DLI; 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="Yd8S3DLI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A2D8C4CEEB; Wed, 10 Sep 2025 15:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757517703; bh=9o0F2OBlrU7QKpOKRU9f0MYopKj2fo8G1bITsYXyof0=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Yd8S3DLIg8n9WuLjTI6F1CFr78dv5G/H61EBigNXRz6tkweHRikKGb6lABaxPag9p HzTEzqW9L1YF4bw0NHGkmzb+LE6/yNcJB/nME6aimTVf5RTzKUguwQc/uQXroqJTZE uoJwUffF9kwc0vmAlCmAIpg8AALXb+Mk1YJoKmphyCmRGFgA1FqfKborzLtJIm3hsQ bjLyoWYbYwS1UAz0M1aKNlZ3dGaf/FBoaOubzgYoCCB04+DDuQ66gnS8YVwqpx1j8t d6RoGp/2MUETzS/zzA0emErlPjjPpYWDlK+kN3ZBzTURfEcnrDDz/hj9yL+ok77yhx hWJfPuQinH0eg== Message-ID: <7819419cf0cb50d8130dc6b747765d2b8febc88a.camel@kernel.org> Subject: Re: client can crash nfsd4_encode_fattr4() by setting bit 84 From: Jeff Layton To: Chuck Lever , rtm@csail.mit.edu Cc: NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org Date: Wed, 10 Sep 2025 11:21:40 -0400 In-Reply-To: <08216553-b703-48d1-a321-22079216ec5d@oracle.com> References: <53032.1757512512@30-10-113.wireless.csail.mit.edu> <0f0c9878-b45f-49c1-b9e8-9ee4b830d51e@oracle.com> <7dcc3c5228fd4fbe7f9d7746d2fd0f99c6dc3a99.camel@kernel.org> <08216553-b703-48d1-a321-22079216ec5d@oracle.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv 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linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-09-10 at 11:10 -0400, Chuck Lever wrote: > On 9/10/25 11:08 AM, Jeff Layton wrote: > > On Wed, 2025-09-10 at 10:53 -0400, Chuck Lever wrote: > > > On 9/10/25 10:49 AM, Jeff Layton wrote: > > > > On Wed, 2025-09-10 at 09:55 -0400, rtm@csail.mit.edu wrote: > > > > > Entry 84 (and a few neighbors) in nfsd4_enc_fattr4_encode_ops[] i= s > > > > > NULL, so if a client sets that bit in an OP_VERIFY bitmask, the s= erver > > > > > will crash here in nfsd_encode_fattr4(): > > > > >=20 > > > > > for_each_set_bit(bit, attr_bitmap, > > > > > ARRAY_SIZE(nfsd4_enc_fattr4_encode_ops))= { > > > > > status =3D nfsd4_enc_fattr4_encode_ops[bit](xdr, = &args); > > > >=20 > > > > Thanks. That looks like a real bug, alright. I think we just need t= o > > > > check that nfsd4_enc_fattr4_encode_ops[bit] is non-NULL before call= ing > > > > its handler. > > > >=20 > > > > Care to propose a patch? > > >=20 > > > 597 #define FATTR4_WORD2_XATTR_SUPPORT BIT(FATTR4_XATTR_SUPPORT = - > > > 64) > > > 598 #define FATTR4_WORD2_TIME_DELEG_ACCESS BIT(FATTR4_TIME_DELEG_ACC= ESS > > > - 64) > > > 599 #define FATTR4_WORD2_TIME_DELEG_MODIFY BIT(FATTR4_TIME_DELEG_MOD= IFY > > > - 64) > > > 600 #define FATTR4_WORD2_OPEN_ARGUMENTS BIT(FATTR4_OPEN_ARGUMENTS= - > > > 64) > > >=20 > > > I think entries for time_deleg_access and time_deleg_modify are missi= ng > > > in nfsd4_enc_fattr4_encode_ops... > > >=20 > >=20 > > Those are typically requested in CB_GETATTR calls. I'm not sure those > > are legit to request in a GETATTR. Are they? > >=20 >=20 > I think GETATTR needs to skip those, and not return an error. So they > need to be defined as noops, probably. Nod. That looks like the best fix. --=20 Jeff Layton