diff mbox series

[v3,1/2] Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor()

Message ID 20230630153315.v3.1.I3b7c8905728f3124576361ca35ed28e37f12f5d1@changeid
State New
Headers
Series [v3,1/2] Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor() |

Commit Message

Doug Anderson June 30, 2023, 10:33 p.m. UTC 
  KASAN reports that there's a use-after-free in
hci_remove_adv_monitor(). Trawling through the disassembly, you can
see that the complaint is from the access in bt_dev_dbg() under the
HCI_ADV_MONITOR_EXT_MSFT case. The problem case happens because
msft_remove_monitor() can end up freeing the monitor
structure. Specifically:
  hci_remove_adv_monitor() ->
  msft_remove_monitor() ->
  msft_remove_monitor_sync() ->
  msft_le_cancel_monitor_advertisement_cb() ->
  hci_free_adv_monitor()

Let's fix the problem by just stashing the relevant data when it's
still valid.

Fixes: 7cf5c2978f23 ("Bluetooth: hci_sync: Refactor remove Adv Monitor")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v3:
- Back to v1 where we stash the handle in a local.

Changes in v2:
- Move the print, don't stash handle in a local.

 net/bluetooth/hci_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

patchwork-bot+bluetooth@kernel.org July 5, 2023, 11 p.m. UTC | #1 
Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Fri, 30 Jun 2023 15:33:14 -0700 you wrote:
> KASAN reports that there's a use-after-free in
> hci_remove_adv_monitor(). Trawling through the disassembly, you can
> see that the complaint is from the access in bt_dev_dbg() under the
> HCI_ADV_MONITOR_EXT_MSFT case. The problem case happens because
> msft_remove_monitor() can end up freeing the monitor
> structure. Specifically:
>   hci_remove_adv_monitor() ->
>   msft_remove_monitor() ->
>   msft_remove_monitor_sync() ->
>   msft_le_cancel_monitor_advertisement_cb() ->
>   hci_free_adv_monitor()
> 
> [...]

Here is the summary with links:
  - [v3,1/2] Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_remove_adv_monitor()
    https://git.kernel.org/bluetooth/bluetooth-next/c/2648c5eb33ca
  - [v3,2/2] Bluetooth: hci_sync: Don't double print name in add/remove adv_monitor
    https://git.kernel.org/bluetooth/bluetooth-next/c/22d2055a576d

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 48917c68358d..dbb2043a9112 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1972,6 +1972,7 @@  static int hci_remove_adv_monitor(struct hci_dev *hdev,
 				  struct adv_monitor *monitor)
 {
 	int status = 0;
+	int handle;
 
 	switch (hci_get_adv_monitor_offload_ext(hdev)) {
 	case HCI_ADV_MONITOR_EXT_NONE: /* also goes here when powered off */
@@ -1980,9 +1981,10 @@  static int hci_remove_adv_monitor(struct hci_dev *hdev,
 		goto free_monitor;
 
 	case HCI_ADV_MONITOR_EXT_MSFT:
+		handle = monitor->handle;
 		status = msft_remove_monitor(hdev, monitor);
 		bt_dev_dbg(hdev, "%s remove monitor %d msft status %d",
-			   hdev->name, monitor->handle, status);
+			   hdev->name, handle, status);
 		break;
 	}