lkml.org 
[lkml]   [2024]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 4/5] uio_hv_generic: Don't free decrypted memory
    Date
    From: Rick Edgecombe <rick.p.edgecombe@intel.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 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@intel.com>
    Signed-off-by: Michael Kelley <mhklinux@outlook.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;
    }

    --
    2.25.1

    \
     
     \ /
      Last update: 2024-05-27 15:44    [W:3.205 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site