netdev - Re: [PATCH net-next] net: lan743x: fix 'channel' index check before writing ptp->extts[]

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <52d96554-23f6-4bde-84d9-e0a7a40b0bc3@bell-sw.com>
Date: Mon, 26 May 2025 08:42:30 +0000
From: Alexey Kodanev <aleksei.kodanev@...l-sw.com>
To: Rengarajan.S@...rochip.com, netdev@...r.kernel.org
Cc: andrew+netdev@...n.ch, Bryan.Whitehead@...rochip.com,
 davem@...emloft.net, Raju.Lakkaraju@...rochip.com, pabeni@...hat.com,
 kuba@...nel.org, edumazet@...gle.com, UNGLinuxDriver@...rochip.com,
 richardcochran@...il.com
Subject: Re: [PATCH net-next] net: lan743x: fix 'channel' index check before
 writing ptp->extts[]

Hi Rengarajan!
On 23.05.2025 20:21, Rengarajan.S@...rochip.com wrote:
> Hi Alexey,
> 
> On Thu, 2025-05-22 at 14:13 +0000, Alexey Kodanev wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you
>> know the content is safe
>>
>> Before calling lan743x_ptp_io_event_clock_get(), the 'channel' value
>> is checked against the maximum value of
>> PCI11X1X_PTP_IO_MAX_CHANNELS(8).
>> This seems correct at first and aligns with the PTP interrupt status
>> register (PTP_INT_STS) specifications.
>>
>> However, lan743x_ptp_io_event_clock_get() writes to ptp->extts[] with
>> only LAN743X_PTP_N_EXTTS(4) elements, using channel as an index:
>>
>>     lan743x_ptp_io_event_clock_get(..., u8 channel,...)
>>     {
>>         ...
>>         /* Update Local timestamp */
>>         extts = &ptp->extts[channel];
>>         extts->ts.tv_sec = sec;
>>         ...
>>     }
>>
> 
> As per the PTP_INT_STS definition, there are 8 sets of capture
> registers that can be configured as GPIO inputs. However, using
> LAN743X_PTP_N_EXTTS (4) restricts processing to only 4 GPIOs. Would it
> be more appropriate to update LAN743X_PTP_N_EXTTS to 8? This would
> ensure that extts = &ptp->extts[channel]; remains valid for all 8
> potential channel indices. 
> 

Yes, thought about the same, but I'm not sure why it was initially
limited to using only 4 channels in LAN743X_PTP_N_EXTTS.

Would it be okay to add the following to the patch?

--- a/drivers/net/ethernet/microchip/lan743x_ptp.h
+++ b/drivers/net/ethernet/microchip/lan743x_ptp.h
@@ -18,9 +18,8 @@
  */
 #define LAN743X_PTP_N_EVENT_CHAN       2
 #define LAN743X_PTP_N_PEROUT           LAN743X_PTP_N_EVENT_CHAN
-#define LAN743X_PTP_N_EXTTS            4
+#define LAN743X_PTP_N_EXTTS            8       /* supports 8 GPIOs */
 #define LAN743X_PTP_N_PPS              0
-#define PCI11X1X_PTP_IO_MAX_CHANNELS   8
 #define PTP_CMD_CTL_TIMEOUT_CNT                50


>> To avoid a potential out-of-bounds write, let's use the maximum
>> value actually defined for the timestamp array to ensure valid
>> access to ptp->extts[channel] within its actual bounds.
>>
>> Detected using the static analysis tool - Svace.
>> Fixes: 60942c397af6 ("net: lan743x: Add support for PTP-IO Event
>> Input External Timestamp (extts)")
>> Signed-off-by: Alexey Kodanev <aleksei.kodanev@...l-sw.com>
>> ---
>>
>> Note that PCI11X1X_PTP_IO_MAX_CHANNELS will be unused after this
>> patch.
>> Could it perhaps be used to define LAN743X_PTP_N_EXTTS to support
>> size 8?
>>
>>  drivers/net/ethernet/microchip/lan743x_ptp.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/microchip/lan743x_ptp.c
>> b/drivers/net/ethernet/microchip/lan743x_ptp.c
>> index 0be44dcb3393..1ef7978e768b 100644
>> --- a/drivers/net/ethernet/microchip/lan743x_ptp.c
>> +++ b/drivers/net/ethernet/microchip/lan743x_ptp.c
>> @@ -1121,7 +1121,7 @@ static long lan743x_ptpci_do_aux_work(struct
>> ptp_clock_info *ptpci)
>>                                                         PTP_INT_IO_FE
>> _MASK_) >>
>>                                                         PTP_INT_IO_FE
>> _SHIFT_);
>>                                 if (channel >= 0 &&
>> -                                   channel <
>> PCI11X1X_PTP_IO_MAX_CHANNELS) {
>> +                                   channel < LAN743X_PTP_N_EXTTS) {
>>                                         lan743x_ptp_io_event_clock_ge
>> t(adapter,
>>                                                                      
>>   true,
>>                                                                      
>>   channel,
>> @@ -1154,7 +1154,7 @@ static long lan743x_ptpci_do_aux_work(struct
>> ptp_clock_info *ptpci)
>>                                                        PTP_INT_IO_RE_
>> MASK_) >>
>>                                                        PTP_INT_IO_RE_
>> SHIFT_);
>>                                 if (channel >= 0 &&
>> -                                   channel <
>> PCI11X1X_PTP_IO_MAX_CHANNELS) {
>> +                                   channel < LAN743X_PTP_N_EXTTS) {
>>                                         lan743x_ptp_io_event_clock_ge
>> t(adapter,
>>                                                                      
>>   false,
>>                                                                      
>>   channel,
>> --
>> 2.25.1
>>