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 C7A452E611D; Tue, 15 Jul 2025 13:29:12 +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=1752586152; cv=none; b=Pqm5HyzaIp+0ux6VVY3e4ckmAvvsKT0HPH1g0RRzvWAB56O/U149evO3WVZLfJr/ik3NSeSzcKjd4uzq+Ho+H4C9Kj6hWMKHLFEzEg/ZF5Mr2IlzOad24B4sI6L7enD4eAPCyxoSQJ7sfdpkCR4d8iXixqUif5zvabedZb5ymw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752586152; c=relaxed/simple; bh=tr8sNgZY7+60KRbkkZ4cZrfMm2uuV9MoirheWCyiiO0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DBrw/JgNe3PkYriqXf3wxfvGxaknsUVDKffKVt3H3/87s6+ZhtAFC9NNpueLPH8/RIy4CPPyMW4etjhBwcSMjY0gffG7Gy5UqkLT4sPbwNJhSSFAatqK6g6JQdfOGcifSnVC6a6F5bR5mQL5jIO2W/MJzxSoPY3EhFwCst/5L3E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gqCfdeE+; 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="gqCfdeE+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C72BC4CEE3; Tue, 15 Jul 2025 13:29:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752586152; bh=tr8sNgZY7+60KRbkkZ4cZrfMm2uuV9MoirheWCyiiO0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gqCfdeE+25bV/uzDA7xJt+TmPjqo74C45BvH5S3U78vJgIxgXaLOHm1/OqQboXtfE p7ZnFycbtbpBFxs2BxbdDXMiwadpkEqc3E22MHwxv4+ZUj70CVl+HJ2y8nvh1r7QkU zu/4T6E3zhZ7ndg97W8KSfBmZmbDottBcTrfV+NQ= 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 5.15 08/77] vsock: Fix transport_* TOCTOU Date: Tue, 15 Jul 2025 15:13:07 +0200 Message-ID: <20250715130752.020888614@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250715130751.668489382@linuxfoundation.org> References: <20250715130751.668489382@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 5.15-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 9a1788bd5c789..f2caef4cda67d 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -400,6 +400,8 @@ 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; @@ -457,6 +459,8 @@ 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; @@ -472,12 +476,15 @@ 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 @@ -501,8 +508,16 @@ 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 || @@ -521,6 +536,9 @@ 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