[PATCH] Bluetooth: MGMT: Fix list corruption and UAF in command complete handlers

[Wang Tao]

Commit 302a1f674c00 ("Bluetooth: MGMT: Fix possible UAFs") introduced
mgmt_pending_valid(), which not only validates the pending command but
also unlinks it from the pending list if it is valid. This change in
semantics requires updates to several completion handlers to avoid list
corruption and memory safety issues.

This patch addresses two left-over issues from the aforementioned rework:

1. In mgmt_add_adv_patterns_monitor_complete(), mgmt_pending_remove()
is replaced with mgmt_pending_free() in the success path. Since
mgmt_pending_valid() already unlinks the command at the beginning of
the function, calling mgmt_pending_remove() leads to a double list_del()
and subsequent list corruption/kernel panic.

2. In set_mesh_complete(), the use of mgmt_pending_foreach() in the error
path is removed. Since the current command is already unlinked by
mgmt_pending_valid(), this foreach loop would incorrectly target other
pending mesh commands, potentially freeing them while they are still being
processed concurrently (leading to UAFs). The redundant mgmt_cmd_status()
is also simplified to use cmd->opcode directly.

Fixes: 302a1f674c00 ("Bluetooth: MGMT: Fix possible UAFs")
Signed-off-by: Wang Tao <wangtao554@xxxxxxxxxx>
---
 net/bluetooth/mgmt.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index a7238fd3b03b..d52238ce6a9a 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -2195,10 +2195,7 @@ static void set_mesh_complete(struct hci_dev *hdev, void *data, int err)
 	sk = cmd->sk;
 
 	if (status) {
-		mgmt_cmd_status(cmd->sk, hdev->id, MGMT_OP_SET_MESH_RECEIVER,
-				status);
-		mgmt_pending_foreach(MGMT_OP_SET_MESH_RECEIVER, hdev, true,
-				     cmd_status_rsp, &status);
+		mgmt_cmd_status(cmd->sk, hdev->id, cmd->opcode, status);
 		goto done;
 	}
 
@@ -5377,7 +5374,7 @@ static void mgmt_add_adv_patterns_monitor_complete(struct hci_dev *hdev,
 
 	mgmt_cmd_complete(cmd->sk, cmd->hdev->id, cmd->opcode,
 			  mgmt_status(status), &rp, sizeof(rp));
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 
 	hci_dev_unlock(hdev);
 	bt_dev_dbg(hdev, "add monitor %d complete, status %d",
-- 
2.34.1