Patch "uio_hv_generic: Don't free decrypted memory" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    uio_hv_generic: Don't free decrypted memory

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     uio_hv_generic-don-t-free-decrypted-memory.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7746ff36adb01d2ef88ab90461fef6c6e4ed215d
Author: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
Date:   Mon Mar 11 09:15:57 2024 -0700

    uio_hv_generic: Don't free decrypted memory
    
    [ Upstream commit 3d788b2fbe6a1a1a9e3db09742b90809d51638b7 ]
    
    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 VMBus device UIO 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@xxxxxxxxx>
    Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
    Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
    Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240311161558.1310-5-mhklinux@xxxxxxxxxxx
    Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
    Message-ID: <20240311161558.1310-5-mhklinux@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 20d9762331bd7..6be3462b109ff 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;
 	}