From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792441936; b=HaJJucZBY+aI+idMLV0UILDzduTjkzYxb3UQO1piNF2RGGGOyuRwr7JvWyjHqjRx+Uro giJxNIW06qWnsE2Woe8vA8zCpFdxRxUgvPeZlC76D1ZmPHKCtx+icoSFLudSk6DsDVxSi KwYMVp1a88BTS78da2r8lpwcI6u+IVn7+dMw6xFifG9jQKzoJy0wxCdwXATbKFOGXHkMy Mgoa+9VnlTYPPc4F9xJvWZUM+DyYjXsI1biJTSYDDA2PhMuJcVHJGmE1NkwQYQ8NZNrQi Qyy1Q6yHtG+uY00lMO7hEiGaH7ZSOFYR0Cd5WzJRIsfmJ516q9QWigjDZNDbR7Pzvog== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792441936; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=6JZ6owAUfodkQDSu5cz9f3U1hSFgVs7lIZQwMs65d7c=; b=lcGlvVnO+NwL7Jvin6kciMHRdSBfw0AObrGIVaR8EN1rTGGxhhj/nhZY4mCRmeFqHMBV jjDR2cq8aD/k9xrAWYf+Oh0N1ZXatn7HgFVAotD6t2gUiFcfmRnm2hTBamo32eAbnaPiu wfMFADDZTxxi9krTpcZ7J59llDVLWaz7IRpbfbaLxccHRo4tGh+ybOCdQnpTSbRdOmkrK dJ2hYcFRuG8zpfodUvmLvzvt9Mmh+rVSrNVwZUD5TTb3mTT5OIMSRZl/4+B7KSdhzxE2X kauo/kIxAcbh/92SJEsGhtcKSHi3Scf4oHoaQ1d4o3jJ965rFJDFFiFOUvtGVUHX4Jw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CUUnoV2S; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with UTF8SMTPS id E7564606A319; Mon, 19 Oct 2026 20:32:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CUUnoV2S Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 07C371F000C4; Mon, 19 Oct 2026 20:32:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792441935; bh=6JZ6owAUfodkQDSu5cz9f3U1hSFgVs7lIZQwMs65d7c=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=CUUnoV2SJv2FTIJiSh91486w2lDw+7kQ7aGLKU8YR2fwDr3V5BWxwtHu8T3Vc+8DZ Wr2QoUEbo/ckUxXITUoZGIZDGKAYheFOvIAME5vx4+JUljuTxD8oX1t8kfzbqkjvrL JlnA2g3obr/iDb0LIT1qZ1fXpFKOQqHLTSKnIJ6uhiO+Fxf0nZTfAr7DAV9AXrz5FW uXnBzpgBwgJJWBqm7wrevI5mpoVQ0P26CtspvqdZk1/3/Zz3P/C5Bck3K3sk62Q+ya bw+0pp+k4II3XQ2cqT4IsfSXmB6WIQNEU2Cs9mFXa7XMV5EwHhCRExRAZsoqnqysM4 ze0QhufHlaXxA== Date: Mon, 19 Oct 2026 23:32:11 +0300 From: Jarkko Sakkinen To: Eric Biggers Cc: David Howells , keyrings@vger.kernel.org, stable@vger.kernel.org, Paul Moore , James Morris , "Serge E. Hallyn" , open list , "open list:SECURITY SUBSYSTEM" Subject: Re: [PATCH v2 1/6] KEYS: Expand key->{datalen,quotalen} to unsigned int Message-ID: References: <20261019181732.449591-1-jarkko@kernel.org> <20261019181732.449591-2-jarkko@kernel.org> <20261019191248.GA65095@quark> X-Mailing-List: keyrings@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261019191248.GA65095@quark> On Mon, Oct 19, 2026 at 12:12:48PM -0700, Eric Biggers wrote: > On Mon, Oct 19, 2026 at 09:17:21PM +0300, Jarkko Sakkinen wrote: > > In key_alloc() and key_payload_reserve(), key->quotalen and key->datalen > > can receive values larger than USHRT_MAX. > > Could use an explanation about how this can happen. A keyring with more > than 16383 links, I guess? It is good to sanity check these given the source of origin. I tried to implement your example and I think I was successful. Here's what I did: keyctl new_session >/dev/null owner=$(keyctl newring owner @s) keeper=$(keyctl newring keeper @s) for ((i=0; i<16384; i++)); do key=$(keyctl add user "k$i" x "$keeper") keyctl link "$key" "$owner" done awk -v uid="$(id -u):" '$1 == uid {print $NF}' /proc/key-users keyctl clear "$owner" awk -v uid="$(id -u):" '$1 == uid {print $NF}' /proc/key-users It is mostly safe from unprivileged user as /proc/sys/kernel/keys/maxkeys and /proc/sys/kernel/keys/maxbytes are by default set to 200 and 20000. When I run it as root, this what I get on first run: 252793/25000000 252793/25000000 Second run: 383862/25000000 383862/25000000 And third run for good measure: 514934/25000000 514934/25000000 So yeah, it is right on the uapi surface easily accessible :-) > > - Eric Br, Jarkko