Return-path: Received: from m12-17.163.com ([220.181.12.17]:39162 "EHLO m12-17.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752052AbcAGLvo (ORCPT ); Thu, 7 Jan 2016 06:51:44 -0500 From: Jia-Ju Bai To: sgruszka@redhat.com, kvalo@codeaurora.org Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] iwl4965: Fix a null pointer dereference in il_tx_queue_free and il_cmd_queue_free Date: Thu, 7 Jan 2016 19:51:38 +0800 Message-Id: <1452167498-10823-1-git-send-email-baijiaju1990@163.com> (sfid-20160107_125147_606295_FB50E86B) Sender: linux-wireless-owner@vger.kernel.org List-ID: 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->cmd[i], 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. Signed-off-by: Jia-Ju Bai --- drivers/net/wireless/iwlegacy/common.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/iwlegacy/common.c b/drivers/net/wireless/iwlegacy/common.c index 8871145..2656a15 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) @@ -3076,11 +3080,15 @@ il_tx_queue_init(struct il_priv *il, u32 txq_id) return 0; err: - for (i = 0; i < actual_slots; i++) + for (i = 0; i < actual_slots; i++) { kfree(txq->cmd[i]); + txq->cmd[i] = NULL; + } out_free_arrays: kfree(txq->meta); + txq->meta = NULL; kfree(txq->cmd); + txq->cmd = NULL; return -ENOMEM; } -- 1.7.9.5