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Subject: Re: [PATCH v2] thunderbolt: Fix to check for kmemdup failure
To:     Aditya Pakki <pakki001@umn.edu>
Cc:     kjlu@umn.edu, Andreas Noever <andreas.noever@gmail.com>,
        Michael Jamet <michael.jamet@intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        linux-kernel@vger.kernel.org
References: <20190320155754.29731-1-pakki001@umn.edu>
From:   Mukesh Ojha <mojha@codeaurora.org>
Message-ID: <b9901208-9808-1112-a3e3-f4b842323732@codeaurora.org>
Date:   Thu, 21 Mar 2019 02:32:23 +0530
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On 3/20/2019 9:27 PM, Aditya Pakki wrote:
> Memory allocated via kmemdup might fail and return a NULL pointer.
> This patch adds a check on the return value of kmemdup and passes the
> error upstream.
>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
>
> ---
> v1: Missed check on tb_sw_read, suggested by Mukesh
> ---
>   drivers/thunderbolt/switch.c | 22 ++++++++++++++++------
>   1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
> index cd96994dc094..504365d46827 100644
> --- a/drivers/thunderbolt/switch.c
> +++ b/drivers/thunderbolt/switch.c
> @@ -1294,13 +1294,14 @@ int tb_switch_configure(struct tb_switch *sw)
>   	return tb_plug_events_active(sw, true);
>   }
>   
> -static void tb_switch_set_uuid(struct tb_switch *sw)
> +static int tb_switch_set_uuid(struct tb_switch *sw)
>   {
>   	u32 uuid[4];
> -	int cap;
> +	int cap, ret;
>   
> +	ret = 0;
>   	if (sw->uuid)
> -		return;
> +		return ret;
>   y
>   	/*
>   	 * The newer controllers include fused UUID as part of link
> @@ -1308,7 +1309,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
>   	 */
>   	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
>   	if (cap > 0) {
> -		tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
> +		ret = tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
> +		if (ret)
> +			return ret;
>   	} else {
>   		/*
>   		 * ICM generates UUID based on UID and fills the upper
> @@ -1323,6 +1326,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
>   	}
>   
>   	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
> +	if (!sw->uuid)
> +		ret = -ENOMEM;
> +	return ret;
>   }


Thanks for doing the change.

Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>


-Mukesh


>   
>   static int tb_switch_add_dma_port(struct tb_switch *sw)
> @@ -1372,7 +1378,9 @@ static int tb_switch_add_dma_port(struct tb_switch *sw)
>   
>   	if (status) {
>   		tb_sw_info(sw, "switch flash authentication failed\n");
> -		tb_switch_set_uuid(sw);
> +		ret = tb_switch_set_uuid(sw);
> +		if (ret)
> +			return ret;
>   		nvm_set_auth_status(sw, status);
>   	}
>   
> @@ -1422,7 +1430,9 @@ int tb_switch_add(struct tb_switch *sw)
>   		}
>   		tb_sw_dbg(sw, "uid: %#llx\n", sw->uid);
>   
> -		tb_switch_set_uuid(sw);
> +		ret = tb_switch_set_uuid(sw);
> +		if (ret)
> +			return ret;
>   
>   		for (i = 0; i <= sw->config.max_port_number; i++) {
>   			if (sw->ports[i].disabled) {