[RFC,19/28] hw/virtio: Replace g_memdup() by g_memdup2_qemu()

Commit Message

Philippe Mathieu-Daudé Sept. 3, 2021, 11:06 a.m. UTC

Per https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538

  The old API took the size of the memory to duplicate as a guint,
  whereas most memory functions take memory sizes as a gsize. This
  made it easy to accidentally pass a gsize to g_memdup(). For large
  values, that would lead to a silent truncation of the size from 64
  to 32 bits, and result in a heap area being returned which is
  significantly smaller than what the caller expects. This can likely
  be exploited in various modules to cause a heap buffer overflow.

Replace g_memdup() by the safer g_memdup2_qemu() wrapper.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
Should we check in_num/out_num in range?
---
 hw/net/virtio-net.c       | 3 ++-
 hw/virtio/virtio-crypto.c | 7 ++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

Patch

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 16d20cdee52..8fa23d5f941 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1449,7 +1449,8 @@  static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
         }
 
         iov_cnt = elem->out_num;
-        iov2 = iov = g_memdup(elem->out_sg, sizeof(struct iovec) * elem->out_num);
+        iov2 = iov = g_memdup2_qemu(elem->out_sg,
+                                    sizeof(struct iovec) * elem->out_num);
         s = iov_to_buf(iov, iov_cnt, 0, &ctrl, sizeof(ctrl));
         iov_discard_front(&iov, &iov_cnt, sizeof(ctrl));
         if (s != sizeof(ctrl)) {
diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
index 54f9bbb789c..43c1a39e469 100644
--- a/hw/virtio/virtio-crypto.c
+++ b/hw/virtio/virtio-crypto.c
@@ -242,7 +242,8 @@  static void virtio_crypto_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
         }
 
         out_num = elem->out_num;
-        out_iov_copy = g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_num);
+        out_iov_copy = g_memdup2_qemu(elem->out_sg,
+                                      sizeof(out_iov[0]) * out_num);
         out_iov = out_iov_copy;
 
         in_num = elem->in_num;
@@ -605,11 +606,11 @@  virtio_crypto_handle_request(VirtIOCryptoReq *request)
     }
 
     out_num = elem->out_num;
-    out_iov_copy = g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_num);
+    out_iov_copy = g_memdup2_qemu(elem->out_sg, sizeof(out_iov[0]) * out_num);
     out_iov = out_iov_copy;
 
     in_num = elem->in_num;
-    in_iov_copy = g_memdup(elem->in_sg, sizeof(in_iov[0]) * in_num);
+    in_iov_copy = g_memdup2_qemu(elem->in_sg, sizeof(in_iov[0]) * in_num);
     in_iov = in_iov_copy;
 
     if (unlikely(iov_to_buf(out_iov, out_num, 0, &req, sizeof(req))