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 1C67D2E266C; Tue, 15 Jul 2025 13:23:29 +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=1752585809; cv=none; b=kFcVME152DyHS/v2vEOZFMXfnIisjJUngoOXSShSszItBvuXchHOCUq12iwlYGn2LyfNuibJLi7nLkjjYw72wYvkIP4s9hYYZCtDi7/9xjRyosszz5eSRq9MgYCSS/9yKIKrbN0k9DsA8LSKm46hvlXH7c/Lz9bgfnOVAP8OJKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752585809; c=relaxed/simple; bh=dWDPQVhl1Tru1KXdKBVpbkvqwHrWBBOOCliuG9Yq4+w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tIhRpub+Q0cEfJgv07zRm7GO9qQd4/4Iim2xGzBHf1kRiFdZINSn/SCWe+jY8QQ8xwkIGfdgi5PgZycxmngvmP09V2Ya2+zGJLbVdn43Q5+kPzBzeeKClH650x0MNtwFqUyVshq/LAPjCCLauhIkg3NDCkQyB6/NX+KlQvtuBKw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mkYPw3+g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mkYPw3+g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5134C4CEE3; Tue, 15 Jul 2025 13:23:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752585809; bh=dWDPQVhl1Tru1KXdKBVpbkvqwHrWBBOOCliuG9Yq4+w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mkYPw3+gGJL+NufZecur624NWq0ND3+a36dkcOy79qyOq5Bc6rek+seWdaVhua8TN 0IJUVFmhznah84meNxwNxgrnyTbRMbN8jy5GoOd+dJVLuvlw4p1N21NGvSKmDhokyW ji3VdQ8lKOTsITXGPAdPHvghaFN8CGafLYTx/6sI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefano Garzarella , Michal Luczaj , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 016/109] vsock: Fix transport_* TOCTOU Date: Tue, 15 Jul 2025 15:12:32 +0200 Message-ID: <20250715130759.529718667@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250715130758.864940641@linuxfoundation.org> References: <20250715130758.864940641@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Luczaj [ Upstream commit 687aa0c5581b8d4aa87fd92973e4ee576b550cdf ] Transport assignment may race with module unload. Protect new_transport from becoming a stale pointer. This also takes care of an insecure call in vsock_use_local_transport(); add a lockdep assert. BUG: unable to handle page fault for address: fffffbfff8056000 Oops: Oops: 0000 [#1] SMP KASAN RIP: 0010:vsock_assign_transport+0x366/0x600 Call Trace: vsock_connect+0x59c/0xc40 __sys_connect+0xe8/0x100 __x64_sys_connect+0x6e/0xc0 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Reviewed-by: Stefano Garzarella Signed-off-by: Michal Luczaj Link: https://patch.msgid.link/20250703-vsock-transports-toctou-v4-2-98f0eb530747@rbox.co Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/vmw_vsock/af_vsock.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index dc62b30c0be5d..58b7404a0da05 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -406,6 +406,8 @@ EXPORT_SYMBOL_GPL(vsock_enqueue_accept); static bool vsock_use_local_transport(unsigned int remote_cid) { + lockdep_assert_held(&vsock_register_mutex); + if (!transport_local) return false; @@ -463,6 +465,8 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) remote_flags = vsk->remote_addr.svm_flags; + mutex_lock(&vsock_register_mutex); + switch (sk->sk_type) { case SOCK_DGRAM: new_transport = transport_dgram; @@ -478,12 +482,15 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) new_transport = transport_h2g; break; default: - return -ESOCKTNOSUPPORT; + ret = -ESOCKTNOSUPPORT; + goto err; } if (vsk->transport) { - if (vsk->transport == new_transport) - return 0; + if (vsk->transport == new_transport) { + ret = 0; + goto err; + } /* transport->release() must be called with sock lock acquired. * This path can only be taken during vsock_connect(), where we @@ -507,8 +514,16 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) /* We increase the module refcnt to prevent the transport unloading * while there are open sockets assigned to it. */ - if (!new_transport || !try_module_get(new_transport->module)) - return -ENODEV; + if (!new_transport || !try_module_get(new_transport->module)) { + ret = -ENODEV; + goto err; + } + + /* It's safe to release the mutex after a successful try_module_get(). + * Whichever transport `new_transport` points at, it won't go away until + * the last module_put() below or in vsock_deassign_transport(). + */ + mutex_unlock(&vsock_register_mutex); if (sk->sk_type == SOCK_SEQPACKET) { if (!new_transport->seqpacket_allow || @@ -527,6 +542,9 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) vsk->transport = new_transport; return 0; +err: + mutex_unlock(&vsock_register_mutex); + return ret; } EXPORT_SYMBOL_GPL(vsock_assign_transport); -- 2.39.5