[61/64] vhost-user-gpu: fix OOB write in 'virgl_cmd_get_capset' (CVE-2021-3546)

Commit Message

Michael Roth Oct. 19, 2021, 2:09 p.m. UTC

From: Li Qiang <[e-mail]>

If 'virgl_cmd_get_capset' set 'max_size' to 0,
the 'virgl_renderer_fill_caps' will write the data after the 'resp'.
This patch avoid this by checking the returned 'max_size'.

virtio-gpu fix: abd7f08b23 ("display: virtio-gpu-3d: check
virgl capabilities max_size")

Fixes: CVE-2021-3546
Reported-by: Li Qiang <[e-mail]>
Reviewed-by: Prasad J Pandit <[e-mail]>
Signed-off-by: Li Qiang <[e-mail]>
Reviewed-by: Marc-André Lureau <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Gerd Hoffmann <[e-mail]>
(cherry picked from commit 9f22893adcb02580aee5968f32baa2cd109b3ec2)
Signed-off-by: Michael Roth <[e-mail]>
---
 contrib/vhost-user-gpu/virgl.c | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/contrib/vhost-user-gpu/virgl.c b/contrib/vhost-user-gpu/virgl.c
index a16a311d80..7172104b19 100644
--- a/contrib/vhost-user-gpu/virgl.c
+++ b/contrib/vhost-user-gpu/virgl.c
@@ -177,6 +177,10 @@  virgl_cmd_get_capset(VuGpu *g,
 
     virgl_renderer_get_cap_set(gc.capset_id, &max_ver,
                                &max_size);
+    if (!max_size) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+        return;
+    }
     resp = g_malloc0(sizeof(*resp) + max_size);
 
     resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET;