Return-path: Received: from m12-12.163.com ([220.181.12.12]:48182 "EHLO m12-12.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758042AbcAKNmw (ORCPT ); Mon, 11 Jan 2016 08:42:52 -0500 From: Jia-Ju Bai To: sgruszka@redhat.com, kvalo@codeaurora.org, johannes.berg@intel.com, emmanuel.grumbach@intel.com Cc: ilw@linux.intel.com, linuxwifi@intel.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Jia-Ju Bai Subject: [PATCH v2] iwl4965: Fix a null pointer dereference in il_tx_queue_free and il_cmd_queue_free Date: Mon, 11 Jan 2016 21:42:54 +0800 Message-Id: <1452519775-7049-1-git-send-email-baijiaju1990@163.com> (sfid-20160111_144259_293803_54179D45) 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->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 --- drivers/net/wireless/iwlegacy/common.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) 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; } -- 1.7.9.5