linux-kernel - [PATCH v2 3/5] hv_netvsc: Don't free decrypted memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Mon, 11 Mar 2024 09:15:56 -0700
From: mhkelley58@...il.com
To: rick.p.edgecombe@...el.com,
	kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	gregkh@...uxfoundation.org,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	kirill.shutemov@...ux.intel.com,
	dave.hansen@...ux.intel.com,
	linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-coco@...ts.linux.dev
Cc: sathyanarayanan.kuppuswamy@...ux.intel.com,
	elena.reshetova@...el.com
Subject: [PATCH v2 3/5] hv_netvsc: Don't free decrypted memory

From: Rick Edgecombe <rick.p.edgecombe@...el.com>

In CoCo VMs it is possible for the untrusted host to cause
set_memory_encrypted() or set_memory_decrypted() to fail such that an
error is returned and the resulting memory is shared. Callers need to
take care to handle these errors to avoid returning decrypted (shared)
memory to the page allocator, which could lead to functional or security
issues.

The netvsc driver could free decrypted/shared pages if
set_memory_decrypted() fails. Check the decrypted field in the gpadl
to decide whether to free the memory.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Signed-off-by: Michael Kelley <mhklinux@...look.com>
---
 drivers/net/hyperv/netvsc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 82e9796c8f5e..70b7f91fb96b 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -154,8 +154,11 @@ static void free_netvsc_device(struct rcu_head *head)
 	int i;
 
 	kfree(nvdev->extension);
-	vfree(nvdev->recv_buf);
-	vfree(nvdev->send_buf);
+
+	if (!nvdev->recv_buf_gpadl_handle.decrypted)
+		vfree(nvdev->recv_buf);
+	if (!nvdev->send_buf_gpadl_handle.decrypted)
+		vfree(nvdev->send_buf);
 	bitmap_free(nvdev->send_section_map);
 
 	for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
-- 
2.25.1