From nobody Wed Oct 8 05:52:20 2025 Received: from mailtransmit05.runbox.com (mailtransmit05.runbox.com [185.226.149.38]) (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 4501428A1F5; Wed, 2 Jul 2025 13:38:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.38 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751463541; cv=none; b=Kkg5JvRFeNx0AIylS2rUooSziokt/cSJM9uKooxBLd6ASm4ULxJl8VgTIy+bt3Hvi/0KLafLqyEQXGT3lNlaIAjN0R8w8uaRbK+RDb9BBgKImkjNV78T2akZg5SSg168D6bpmRt0qLvszqNSckEegyCFzc4eSdR34OZ0PiFtv4Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751463541; c=relaxed/simple; bh=xJyaNJQ7LbzJGPjFyc9HUYGLS31iY7vm48JnwuM2+hg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=aw/yQgfHnORnbOVEkJsOQ3Z1c27ZxRcks6O5sZ7q83UAAzgpjTZx4zD0QmrCgqw+EU2KMqvqJmNqoCLGLbSRl7FXITXaFLD4M7c0TGyWEH/Una0D+L4bRQlliDnmME0iaNb3UWmdyxFL0n+J2vytRgAAdi3zE64N+Z5lz/cEsRM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co; spf=pass smtp.mailfrom=rbox.co; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b=TqPekNS9; arc=none smtp.client-ip=185.226.149.38 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rbox.co Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b="TqPekNS9" Received: from mailtransmit03.runbox ([10.9.9.163] helo=aibo.runbox.com) by mailtransmit05.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1uWxfs-00GxS8-DM; Wed, 02 Jul 2025 15:38:56 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector2; h=Cc:To:In-Reply-To:References:Message-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date:From; bh=QANjNkCZa2tpxhq6eTHKRMBXrJr14UZJplu1Q4IRXac=; b=TqPekNS99PHx54hoQEU9loZqjp I/9vGeflCOEd86fcAvOThawzMsvnuMzT8nG7NWkB68wh9BaY8JV6vrGYUL15kdQGghnmVMIXIBWQ3 7m4zYyzpdBYQfIYyLv66Rysr1KQ4bLWuuzH9ALKXf09/fUKnmBGg3ZHnjZez2078Vxz+zx04EmPcd +xus3xE9/yFHYzBNZD2IAhKflHXOoCAe7KgdTapqcuGC1cjnkjgo5BiVvZx9xAy8k5bRBVYDdvL1J yJ2n9pfbyGwC8AL+qth5DEOKhM/WeRIpxJGssUdmj8/mnzXfVDRqn0Ki8lvdYaz0/oHZoC07vpNXl 4Ggg6qpA==; Received: from [10.9.9.73] (helo=submission02.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1uWxfr-0005Hm-TU; Wed, 02 Jul 2025 15:38:56 +0200 Received: by submission02.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1uWxfm-009LQl-68; Wed, 02 Jul 2025 15:38:50 +0200 From: Michal Luczaj Date: Wed, 02 Jul 2025 15:38:43 +0200 Subject: [PATCH net v3 1/3] vsock: Fix transport_{g2h,h2g} TOCTOU Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250702-vsock-transports-toctou-v3-1-0a7e2e692987@rbox.co> References: <20250702-vsock-transports-toctou-v3-0-0a7e2e692987@rbox.co> In-Reply-To: <20250702-vsock-transports-toctou-v3-0-0a7e2e692987@rbox.co> To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Stefan Hajnoczi Cc: virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.2 vsock_find_cid() and vsock_dev_do_ioctl() may race with module unload. transport_{g2h,h2g} may become NULL after the NULL check. Introduce vsock_transport_local_cid() to protect from a potential null-ptr-deref. KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f] RIP: 0010:vsock_find_cid+0x47/0x90 Call Trace: __vsock_bind+0x4b2/0x720 vsock_bind+0x90/0xe0 __sys_bind+0x14d/0x1e0 __x64_sys_bind+0x6e/0xc0 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f] RIP: 0010:vsock_dev_do_ioctl.isra.0+0x58/0xf0 Call Trace: __x64_sys_ioctl+0x12d/0x190 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Suggested-by: Stefano Garzarella Signed-off-by: Michal Luczaj Reviewed-by: Stefano Garzarella --- net/vmw_vsock/af_vsock.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 2e7a3034e965db30b6ee295370d866e6d8b1c341..39473b9e0829f240045262aef00= cbae82a425dcc 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -531,9 +531,25 @@ int vsock_assign_transport(struct vsock_sock *vsk, str= uct vsock_sock *psk) } EXPORT_SYMBOL_GPL(vsock_assign_transport); =20 +/* + * Provide safe access to static transport_{h2g,g2h,dgram,local} callbacks. + * Otherwise we may race with module removal. Do not use on `vsk->transpor= t`. + */ +static u32 vsock_registered_transport_cid(const struct vsock_transport **t= ransport) +{ + u32 cid =3D VMADDR_CID_ANY; + + mutex_lock(&vsock_register_mutex); + if (*transport) + cid =3D (*transport)->get_local_cid(); + mutex_unlock(&vsock_register_mutex); + + return cid; +} + bool vsock_find_cid(unsigned int cid) { - if (transport_g2h && cid =3D=3D transport_g2h->get_local_cid()) + if (cid =3D=3D vsock_registered_transport_cid(&transport_g2h)) return true; =20 if (transport_h2g && cid =3D=3D VMADDR_CID_HOST) @@ -2536,18 +2552,17 @@ static long vsock_dev_do_ioctl(struct file *filp, unsigned int cmd, void __user *ptr) { u32 __user *p =3D ptr; - u32 cid =3D VMADDR_CID_ANY; int retval =3D 0; + u32 cid; =20 switch (cmd) { case IOCTL_VM_SOCKETS_GET_LOCAL_CID: /* To be compatible with the VMCI behavior, we prioritize the * guest CID instead of well-know host CID (VMADDR_CID_HOST). */ - if (transport_g2h) - cid =3D transport_g2h->get_local_cid(); - else if (transport_h2g) - cid =3D transport_h2g->get_local_cid(); + cid =3D vsock_registered_transport_cid(&transport_g2h); + if (cid =3D=3D VMADDR_CID_ANY) + cid =3D vsock_registered_transport_cid(&transport_h2g); =20 if (put_user(cid, p) !=3D 0) retval =3D -EFAULT; --=20 2.49.0