[PATCH v2] tap: fix write-after-free and double free of intr_handle

[Quentin Armitage]

rte_pmd_tun/tap_probe() allocates pmd->intr_handle in eth_dev_tap_create()
and it should not be freed until rte_pmd_tap_remove() is called.

Inspection of tap_rx_intr_vec_set() shows that the call to
tap_tx_intr_vec_uninstall() was calling rte_intr_instance_free() but
tap_tx_intr_vec_install() can then be immediately called, and this then
uses pmd->intr_handle without it being reallocated.

This commit moves the call of rte_intr_instance_free() from
tap_tx_intr_vec_uninstall() to rte_pmd_tap_remove().

Fixes: d61138d4f0e2 ("drivers: remove direct access to interrupt handle")

Changes in v2:
  Move rte_intr_instance_free() from tap_rx_intr_vec_uninstall()
  to tap_dev_close().

Signed-off-by: Quentin Armitage <quentin at armitage.org.uk>
---
 drivers/net/tap/rte_eth_tap.c | 2 ++
 drivers/net/tap/tap_intr.c    | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index bc3d56a311..5495818be6 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -1213,6 +1213,8 @@ tap_dev_close(struct rte_eth_dev *dev)
 	TAP_LOG(DEBUG, "Closing %s Ethernet device on numa %u",
 		tuntap_types[internals->type], rte_socket_id());
 
+	rte_intr_instance_free(internals->intr_handle);
+
 	if (internals->ioctl_sock != -1) {
 		close(internals->ioctl_sock);
 		internals->ioctl_sock = -1;
diff --git a/drivers/net/tap/tap_intr.c b/drivers/net/tap/tap_intr.c
index 56c343acea..a9097def1a 100644
--- a/drivers/net/tap/tap_intr.c
+++ b/drivers/net/tap/tap_intr.c
@@ -34,8 +34,6 @@ tap_rx_intr_vec_uninstall(struct rte_eth_dev *dev)
 	rte_intr_free_epoll_fd(intr_handle);
 	rte_intr_vec_list_free(intr_handle);
 	rte_intr_nb_efd_set(intr_handle, 0);
-
-	rte_intr_instance_free(intr_handle);
 }
 
 /**
-- 
2.34.1