From: Li Qiang <liq3ea@163.com>
Date: Sat, 15 May 2021 20:04:03 -0700
Subject: vhost-user-gpu: abstract vg_cleanup_mapping_iov
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Git-commit: 3ea32d1355d446057c17458238db2749c52ee8f0
References: CVE-2021-3546 bsc#1185981
            CVE-2021-3545 bsc#1185990
            CVE-2021-3544

Currently in vhost-user-gpu, we free resource directly in
the cleanup case of resource. If we change the cleanup logic
we need to change several places, also abstruct a
'vg_create_mapping_iov' can be symmetry with the
'vg_create_mapping_iov'. This is like what virtio-gpu does,
no function changed.

Signed-off-by: Li Qiang <liq3ea@163.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210516030403.107723-9-liq3ea@163.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jose R. Ziviani <jziviani@suse.de>
---
 contrib/vhost-user-gpu/main.c  | 24 ++++++++++++++++++++----
 contrib/vhost-user-gpu/virgl.c |  9 +++++----
 contrib/vhost-user-gpu/vugpu.h |  2 +-
 3 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/contrib/vhost-user-gpu/main.c b/contrib/vhost-user-gpu/main.c
index 9554e8984b878711e5f3dd043101..75c1aa6ed54f08b3d8c141f854aa 100644
--- a/contrib/vhost-user-gpu/main.c
+++ b/contrib/vhost-user-gpu/main.c
@@ -49,6 +49,8 @@ static char *opt_render_node;
 static gboolean opt_virgl;
 
 static void vg_handle_ctrl(VuDev *dev, int qidx);
+static void vg_cleanup_mapping(VuGpu *g,
+                               struct virtio_gpu_simple_resource *res);
 
 static const char *
 vg_cmd_to_string(int cmd)
@@ -379,7 +381,7 @@ vg_resource_destroy(VuGpu *g,
     }
 
     vugbm_buffer_destroy(&res->buffer);
-    g_free(res->iov);
+    vg_cleanup_mapping(g, res);
     pixman_image_unref(res->image);
     QTAILQ_REMOVE(&g->reslist, res, next);
     g_free(res);
@@ -483,6 +485,22 @@ vg_resource_attach_backing(VuGpu *g,
     res->iov_cnt = ab.nr_entries;
 }
 
+/* Though currently only free iov, maybe later will do more work. */
+void vg_cleanup_mapping_iov(VuGpu *g,
+                            struct iovec *iov, uint32_t count)
+{
+    g_free(iov);
+}
+
+static void
+vg_cleanup_mapping(VuGpu *g,
+                   struct virtio_gpu_simple_resource *res)
+{
+    vg_cleanup_mapping_iov(g, res->iov, res->iov_cnt);
+    res->iov = NULL;
+    res->iov_cnt = 0;
+}
+
 static void
 vg_resource_detach_backing(VuGpu *g,
                            struct virtio_gpu_ctrl_command *cmd)
@@ -501,9 +519,7 @@ vg_resource_detach_backing(VuGpu *g,
         return;
     }
 
-    g_free(res->iov);
-    res->iov = NULL;
-    res->iov_cnt = 0;
+    vg_cleanup_mapping(g, res);
 }
 
 static void
diff --git a/contrib/vhost-user-gpu/virgl.c b/contrib/vhost-user-gpu/virgl.c
index 1f7678ecb82432640401636f1276..031e10e8b9f1aa666ab0a8c3ca62 100644
--- a/contrib/vhost-user-gpu/virgl.c
+++ b/contrib/vhost-user-gpu/virgl.c
@@ -113,8 +113,9 @@ virgl_cmd_resource_unref(VuGpu *g,
     virgl_renderer_resource_detach_iov(unref.resource_id,
                                        &res_iovs,
                                        &num_iovs);
-    g_free(res_iovs);
-
+    if (res_iovs != NULL && num_iovs != 0) {
+        vg_cleanup_mapping_iov(g, res_iovs, num_iovs);
+    }
     virgl_renderer_resource_unref(unref.resource_id);
 }
 
@@ -291,7 +292,7 @@ virgl_resource_attach_backing(VuGpu *g,
     ret = virgl_renderer_resource_attach_iov(att_rb.resource_id,
                                        res_iovs, att_rb.nr_entries);
     if (ret != 0) {
-        g_free(res_iovs);
+        vg_cleanup_mapping_iov(g, res_iovs, att_rb.nr_entries);
     }
 }
 
@@ -311,7 +312,7 @@ virgl_resource_detach_backing(VuGpu *g,
     if (res_iovs == NULL || num_iovs == 0) {
         return;
     }
-    g_free(res_iovs);
+    vg_cleanup_mapping_iov(g, res_iovs, num_iovs);
 }
 
 static void
diff --git a/contrib/vhost-user-gpu/vugpu.h b/contrib/vhost-user-gpu/vugpu.h
index 3153c9a6de1409b8a0f0bc16b287..284e19aeb86f5b0e01f11b7d1ab7 100644
--- a/contrib/vhost-user-gpu/vugpu.h
+++ b/contrib/vhost-user-gpu/vugpu.h
@@ -164,7 +164,7 @@ int     vg_create_mapping_iov(VuGpu *g,
                               struct virtio_gpu_resource_attach_backing *ab,
                               struct virtio_gpu_ctrl_command *cmd,
                               struct iovec **iov);
-
+void    vg_cleanup_mapping_iov(VuGpu *g, struct iovec *iov, uint32_t count);
 void    vg_get_display_info(VuGpu *vg, struct virtio_gpu_ctrl_command *cmd);
 
 void    vg_wait_ok(VuGpu *g);
