[RESEND,4/4] NFC: fdp: Fix possible buffer overflow in WCS4000 NFC driver

Message ID 1524045904-7005-5-git-send-email-amit.pundir@linaro.org
State New
Headers show
Series
  • Untitled series #10762
Related show

Commit Message

Amit Pundir April 18, 2018, 10:05 a.m.
From: Suren Baghdasaryan <surenb@google.com>


Possible buffer overflow when reading next_read_size bytes into
tmp buffer after next_read_size was extracted from a previous packet.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

---
 drivers/nfc/fdp/i2c.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

-- 
2.7.4

Comments

Andy Shevchenko April 20, 2018, 12:41 p.m. | #1
On Wed, 2018-04-18 at 15:35 +0530, Amit Pundir wrote:

> +			if (phy->next_read_size >

> FDP_NCI_I2C_MAX_PAYLOAD) {


> +				dev_dbg(&client->dev, "%s: corrupted

> packet\n",

> +					__func__);


If Android people would follow the kernel in reasonable time they may
have noticed Dynamic Debug functionality and how it works.

In this case the __func__ is superfluous.

> +				phy->next_read_size = 5;

> +				goto flush;

> +			}

>  		} else {

>  			phy->next_read_size =

> FDP_NCI_I2C_MIN_PAYLOAD;

>  


-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
Greg Kroah-Hartman April 23, 2018, 9:16 a.m. | #2
On Wed, Apr 18, 2018 at 03:35:04PM +0530, Amit Pundir wrote:
> From: Suren Baghdasaryan <surenb@google.com>

> 

> Possible buffer overflow when reading next_read_size bytes into

> tmp buffer after next_read_size was extracted from a previous packet.

> 

> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

> ---

>  drivers/nfc/fdp/i2c.c | 10 ++++++++++

>  1 file changed, 10 insertions(+)

> 

> diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c

> index c4da50e07bbc..08a4f82a2965 100644

> --- a/drivers/nfc/fdp/i2c.c

> +++ b/drivers/nfc/fdp/i2c.c

> @@ -176,6 +176,16 @@ static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)

>  		/* Packet that contains a length */

>  		if (tmp[0] == 0 && tmp[1] == 0) {

>  			phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;

> +			/*

> +			 * Ensure next_read_size does not exceed sizeof(tmp)

> +			 * for reading that many bytes during next iteration

> +			 */

> +			if (phy->next_read_size > FDP_NCI_I2C_MAX_PAYLOAD) {

> +				dev_dbg(&client->dev, "%s: corrupted packet\n",

> +					__func__);


As Andy points out, no need for __func__ in any dev_dbg() call.

thanks,

greg k-h
Amit Pundir April 23, 2018, 10:02 a.m. | #3
On 23 April 2018 at 14:46, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Wed, Apr 18, 2018 at 03:35:04PM +0530, Amit Pundir wrote:

>> From: Suren Baghdasaryan <surenb@google.com>

>>

>> Possible buffer overflow when reading next_read_size bytes into

>> tmp buffer after next_read_size was extracted from a previous packet.

>>

>> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

>> Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

>> ---

>>  drivers/nfc/fdp/i2c.c | 10 ++++++++++

>>  1 file changed, 10 insertions(+)

>>

>> diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c

>> index c4da50e07bbc..08a4f82a2965 100644

>> --- a/drivers/nfc/fdp/i2c.c

>> +++ b/drivers/nfc/fdp/i2c.c

>> @@ -176,6 +176,16 @@ static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)

>>               /* Packet that contains a length */

>>               if (tmp[0] == 0 && tmp[1] == 0) {

>>                       phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;

>> +                     /*

>> +                      * Ensure next_read_size does not exceed sizeof(tmp)

>> +                      * for reading that many bytes during next iteration

>> +                      */

>> +                     if (phy->next_read_size > FDP_NCI_I2C_MAX_PAYLOAD) {

>> +                             dev_dbg(&client->dev, "%s: corrupted packet\n",

>> +                                     __func__);

>

> As Andy points out, no need for __func__ in any dev_dbg() call.


Hi, Yes i'm working on v2 of this patch and on the comments I got on
another patch in this series.

Thanks,
Amit Pundir

>

> thanks,

>

> greg k-h

Patch

diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c
index c4da50e07bbc..08a4f82a2965 100644
--- a/drivers/nfc/fdp/i2c.c
+++ b/drivers/nfc/fdp/i2c.c
@@ -176,6 +176,16 @@  static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
 		/* Packet that contains a length */
 		if (tmp[0] == 0 && tmp[1] == 0) {
 			phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
+			/*
+			 * Ensure next_read_size does not exceed sizeof(tmp)
+			 * for reading that many bytes during next iteration
+			 */
+			if (phy->next_read_size > FDP_NCI_I2C_MAX_PAYLOAD) {
+				dev_dbg(&client->dev, "%s: corrupted packet\n",
+					__func__);
+				phy->next_read_size = 5;
+				goto flush;
+			}
 		} else {
 			phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;