| Message ID | 1452519775-7049-1-git-send-email-baijiaju1990@163.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Kalle Valo |
| Headers | show |
On Mon, Jan 11, 2016 at 09:42:54PM +0800, Jia-Ju Bai wrote: > 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> -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/wireless/iwlegacy/common.c b/drivers/net/wireless/iwlegacy/common.c index 8871145..092ecbc 100644 --- a/drivers/net/wireless/iwlegacy/common.c +++ b/drivers/net/wireless/iwlegacy/common.c @@ -2794,8 +2794,10 @@ il_tx_queue_free(struct il_priv *il, int txq_id) 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) @@ -2873,8 +2875,10 @@ il_cmd_queue_free(struct il_priv *il) 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) @@ -3080,7 +3084,9 @@ err: kfree(txq->cmd[i]); out_free_arrays: kfree(txq->meta); + txq->meta = NULL; kfree(txq->cmd); + txq->cmd = NULL; return -ENOMEM; }
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> --- drivers/net/wireless/iwlegacy/common.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)