iwl4965: Fix a null pointer dereference in il_tx_queue_free and il_cmd_queue_free
If "txq->cmd = kzalloc(...)" in il_tx_queue_init fails,
"kfree(txq->cmd[i])" in il_tx_queue_free and il_cmd_queue_free
in iwl4965_hw_txq_ctx_free will causes a null pointer dereference,
because txq->cmd is NULL at that time.
This patch fixes this problem by adding a if-check before kfree.
To avoid double free in il_tx_queue_free and il_cmd_queue_free
caused by the fixing, txq->meta and txq->cmd in error handling code
of il_tx_queue_init are assigned null values.
Otherwise, a double free will occur.
This patch has been tested in real device, and it actually fixes the bug.
Thanks Stanislaw for his suggestion.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Julian Calaby <julian.calaby@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index c3afaf7..2cc3d42 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -2792,8 +2792,10 @@
il_tx_queue_unmap(il, txq_id);
/* De-alloc array of command/tx buffers */
- for (i = 0; i < TFD_TX_CMD_SLOTS; i++)
- kfree(txq->cmd[i]);
+ if (txq->cmd) {
+ for (i = 0; i < TFD_TX_CMD_SLOTS; i++)
+ kfree(txq->cmd[i]);
+ }
/* De-alloc circular buffer of TFDs */
if (txq->q.n_bd)
@@ -2871,8 +2873,10 @@
il_cmd_queue_unmap(il);
/* De-alloc array of command/tx buffers */
- for (i = 0; i <= TFD_CMD_SLOTS; i++)
- kfree(txq->cmd[i]);
+ if (txq->cmd) {
+ for (i = 0; i <= TFD_CMD_SLOTS; i++)
+ kfree(txq->cmd[i]);
+ }
/* De-alloc circular buffer of TFDs */
if (txq->q.n_bd)
@@ -3078,7 +3082,9 @@
kfree(txq->cmd[i]);
out_free_arrays:
kfree(txq->meta);
+ txq->meta = NULL;
kfree(txq->cmd);
+ txq->cmd = NULL;
return -ENOMEM;
}