From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: x86@kernel.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
luto@kernel.org, peterz@infradead.org,
kirill.shutemov@linux.intel.com, elena.reshetova@intel.com,
isaku.yamahata@intel.com, seanjc@google.com,
Michael Kelley <mikelley@microsoft.com>,
thomas.lendacky@amd.com, decui@microsoft.com,
sathyanarayanan.kuppuswamy@linux.intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Cc: rick.p.edgecombe@intel.com,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
linux-hyperv@vger.kernel.org
Subject: [RFC 10/10] uio_hv_generic: Don't free decrypted memory
Date: Tue, 17 Oct 2023 13:25:05 -0700 [thread overview]
Message-ID: <20231017202505.340906-11-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20231017202505.340906-1-rick.p.edgecombe@intel.com>
On TDX 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.
uio_hv_generic could free decrypted/shared pages if
set_memory_decrypted() fails.
Check the decrypted field in the gpadl before freeing in order to not
leak the memory.
Only compile tested.
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: linux-hyperv@vger.kernel.org
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
drivers/uio/uio_hv_generic.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 20d9762331bd..6be3462b109f 100644
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -181,12 +181,14 @@ hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
{
if (pdata->send_gpadl.gpadl_handle) {
vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
- vfree(pdata->send_buf);
+ if (!pdata->send_gpadl.decrypted)
+ vfree(pdata->send_buf);
}
if (pdata->recv_gpadl.gpadl_handle) {
vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
- vfree(pdata->recv_buf);
+ if (!pdata->recv_gpadl.decrypted)
+ vfree(pdata->recv_buf);
}
}
@@ -295,7 +297,8 @@ hv_uio_probe(struct hv_device *dev,
ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
RECV_BUFFER_SIZE, &pdata->recv_gpadl);
if (ret) {
- vfree(pdata->recv_buf);
+ if (!pdata->recv_gpadl.decrypted)
+ vfree(pdata->recv_buf);
goto fail_close;
}
@@ -317,7 +320,8 @@ hv_uio_probe(struct hv_device *dev,
ret = vmbus_establish_gpadl(channel, pdata->send_buf,
SEND_BUFFER_SIZE, &pdata->send_gpadl);
if (ret) {
- vfree(pdata->send_buf);
+ if (!pdata->send_gpadl.decrypted)
+ vfree(pdata->send_buf);
goto fail_close;
}
--
2.34.1
prev parent reply other threads:[~2023-10-17 20:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20231017202505.340906-1-rick.p.edgecombe@intel.com>
2023-10-17 20:25 ` [RFC 07/10] hv: Use free_decrypted_pages() Rick Edgecombe
2023-10-17 20:25 ` [RFC 08/10] hv: Track decrypted status in vmbus_gpadl Rick Edgecombe
2023-10-17 20:25 ` [RFC 09/10] hv_nstvsc: Don't free decrypted memory Rick Edgecombe
2023-10-17 20:25 ` Rick Edgecombe [this message]
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