[LTP] [PATCH 0/2] pty: use correct protocol in pty04 based on line discipline

[LTP] [PATCH 0/2] pty: use correct protocol in pty04 based on line discipline

[Vasileios Almpanis via ltp]

Hi,

during testing of the LTP pty test pty04, we observed intermittent
failures caused by unexpected IPv6 packets being received.

The test currently filters packets using ETH_P_ALL. As a result,
packets with protocols other than the expected one (e.g. IPv6) may be
received, leading to data corruption reports such as:

TFAIL: Corrupt data (max 64 of 8191 bytes shown): data[0..64] =
TFAIL: 60 00 00 00 00 24 00 01 00 00 00 00 00 00 00 00
TFAIL: 00 00 00 00 00 00 00 00 ff 02 00 00 00 00 00 00
TFAIL: 00 00 00 00 00 00 00 16 3a 00 05 02 00 00 01 00
TFAIL: 8f 00 6e 8a 00 00 00 01 04 00 00 00 ff 02 00 00

This patch series addresses the issue by selecting the protocol based
on the configured line discipline.

Patch 1 adds a compatibility definition for ETH_P_CAN to the LAPI
headers. Patch 2 updates pty04 to choose the appropriate protocol,
avoiding reception of unrelated packets.

Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>

Vasileios Almpanis (2):
  add ETH_P_CAN compat macro to LAPI headers
  pty04: use the correct protocol per line discipline to avoid extra
    packets

 include/lapi/if_ether.h      |  4 ++++
 testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

-- 
2.43.0


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[LTP] [PATCH 1/2] add ETH_P_CAN compat macro to LAPI headers

[Vasileios Almpanis via ltp]

Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
---
 include/lapi/if_ether.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/lapi/if_ether.h b/include/lapi/if_ether.h
index 536d1863a..423341c57 100644
--- a/include/lapi/if_ether.h
+++ b/include/lapi/if_ether.h
@@ -16,4 +16,8 @@
 # define ETH_P_ALL 0x0003
 #endif
 
+#ifndef ETH_P_CAN
+# define ETH_P_CAN 0x000C
+#endif
+
 #endif /* LAPI_IF_ETHER_H__ */
-- 
2.43.0


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Re: [LTP] [PATCH 1/2] add ETH_P_CAN compat macro to LAPI headers

[Petr Vorel]

Hi Vasileios,

>  include/lapi/if_ether.h | 4 ++++
>  1 file changed, 4 insertions(+)

> diff --git a/include/lapi/if_ether.h b/include/lapi/if_ether.h
> index 536d1863a..423341c57 100644
> --- a/include/lapi/if_ether.h
> +++ b/include/lapi/if_ether.h
> @@ -16,4 +16,8 @@
>  # define ETH_P_ALL 0x0003
>  #endif

> +#ifndef ETH_P_CAN
> +# define ETH_P_CAN 0x000C
> +#endif

This is not needed, because it was added to kernel's
include/uapi/linux/if_ether.h before UAPI creation in v3.7-rc1.
And we now expect kernel >= 4.4 [1].

FYI the fallback was originally added in 2017 in
db141701dd ("Add test for CVE-2017-7308 on a raw socket's ring buffer"),
the supported systems required it back then, but now whole include/lapi/if_ether.h,
could be deleted (as an separate effort). For now it'd be enough just to ignore
this commit (not add it).

Kind regards,
Petr

[1] https://linux-test-project.readthedocs.io/en/latest/users/supported_systems.html

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[LTP] [PATCH 2/2] pty04: use the correct protocol per line discipline to avoid extra packets

[Vasileios Almpanis via ltp]

Use specific protocol filter (ETH_P_IP for N_SLIP, ETH_P_CAN for N_SLCAN)
instead of ETH_P_ALL to avoid catching unrelated packets like IPv6
multicast (MLD) which cause false test failures.

Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
---
 testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/pty/pty04.c b/testcases/kernel/pty/pty04.c
index 204703253..770c053c4 100644
--- a/testcases/kernel/pty/pty04.c
+++ b/testcases/kernel/pty/pty04.c
@@ -258,6 +258,19 @@ static void open_netdev(const struct ldisc_info *ldisc)
 {
 	struct ifreq ifreq = { 0 };
 	struct sockaddr_ll lla = { 0 };
+	int protocol;
+
+	switch (ldisc->n) {
+		case N_SLIP:
+			protocol = ETH_P_IP;
+			break;
+		case N_SLCAN:
+			protocol = ETH_P_CAN;
+			break;
+		default:
+			protocol = ETH_P_ALL;
+			break;
+	}
 
 	SAFE_IOCTL(pts, SIOCGIFNAME, ifreq.ifr_name);
 	tst_res(TINFO, "Netdev is %s", ifreq.ifr_name);
@@ -282,7 +295,7 @@ static void open_netdev(const struct ldisc_info *ldisc)
 	SAFE_IOCTL(sk, SIOCGIFINDEX, &ifreq);
 
 	lla.sll_family = PF_PACKET;
-	lla.sll_protocol = htons(ETH_P_ALL);
+	lla.sll_protocol = htons(protocol);
 	lla.sll_ifindex = ifreq.ifr_ifindex;
 	SAFE_BIND(sk, (struct sockaddr *)&lla, sizeof(struct sockaddr_ll));
 
-- 
2.43.0


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Re: [LTP] [PATCH 2/2] pty04: use the correct protocol per line discipline to avoid extra packets

[Petr Vorel]

Hi Vasileios,

> Use specific protocol filter (ETH_P_IP for N_SLIP, ETH_P_CAN for N_SLCAN)
> instead of ETH_P_ALL to avoid catching unrelated packets like IPv6
> multicast (MLD) which cause false test failures.

LGTM.
@Martin: could you please double check?

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

> Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
> ---
>  testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)

> diff --git a/testcases/kernel/pty/pty04.c b/testcases/kernel/pty/pty04.c
> index 204703253..770c053c4 100644
> --- a/testcases/kernel/pty/pty04.c
> +++ b/testcases/kernel/pty/pty04.c
> @@ -258,6 +258,19 @@ static void open_netdev(const struct ldisc_info *ldisc)
>  {
>  	struct ifreq ifreq = { 0 };
>  	struct sockaddr_ll lla = { 0 };
> +	int protocol;
> +
> +	switch (ldisc->n) {
> +		case N_SLIP:
> +			protocol = ETH_P_IP;
> +			break;
> +		case N_SLCAN:
> +			protocol = ETH_P_CAN;
> +			break;
> +		default:
> +			protocol = ETH_P_ALL;
> +			break;
> +	}

>  	SAFE_IOCTL(pts, SIOCGIFNAME, ifreq.ifr_name);
>  	tst_res(TINFO, "Netdev is %s", ifreq.ifr_name);
> @@ -282,7 +295,7 @@ static void open_netdev(const struct ldisc_info *ldisc)
>  	SAFE_IOCTL(sk, SIOCGIFINDEX, &ifreq);

>  	lla.sll_family = PF_PACKET;
> -	lla.sll_protocol = htons(ETH_P_ALL);
> +	lla.sll_protocol = htons(protocol);
>  	lla.sll_ifindex = ifreq.ifr_ifindex;
>  	SAFE_BIND(sk, (struct sockaddr *)&lla, sizeof(struct sockaddr_ll));

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Re: [LTP] [PATCH 2/2] pty04: use the correct protocol per line discipline to avoid extra packets

[Martin Doucha]

Hi!
Good catch, but it'd be cleaner to add a "protocol" field to the 
ldisc_info structure instead of selecting protocol in a switch block.

On 2/6/26 13:51, Vasileios Almpanis via ltp wrote:
> Use specific protocol filter (ETH_P_IP for N_SLIP, ETH_P_CAN for N_SLCAN)
> instead of ETH_P_ALL to avoid catching unrelated packets like IPv6
> multicast (MLD) which cause false test failures.
> 
> Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
> ---
>   testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/testcases/kernel/pty/pty04.c b/testcases/kernel/pty/pty04.c
> index 204703253..770c053c4 100644
> --- a/testcases/kernel/pty/pty04.c
> +++ b/testcases/kernel/pty/pty04.c
> @@ -258,6 +258,19 @@ static void open_netdev(const struct ldisc_info *ldisc)
>   {
>   	struct ifreq ifreq = { 0 };
>   	struct sockaddr_ll lla = { 0 };
> +	int protocol;
> +
> +	switch (ldisc->n) {
> +		case N_SLIP:
> +			protocol = ETH_P_IP;
> +			break;
> +		case N_SLCAN:
> +			protocol = ETH_P_CAN;
> +			break;
> +		default:
> +			protocol = ETH_P_ALL;
> +			break;
> +	}
>   
>   	SAFE_IOCTL(pts, SIOCGIFNAME, ifreq.ifr_name);
>   	tst_res(TINFO, "Netdev is %s", ifreq.ifr_name);
> @@ -282,7 +295,7 @@ static void open_netdev(const struct ldisc_info *ldisc)
>   	SAFE_IOCTL(sk, SIOCGIFINDEX, &ifreq);
>   
>   	lla.sll_family = PF_PACKET;
> -	lla.sll_protocol = htons(ETH_P_ALL);
> +	lla.sll_protocol = htons(protocol);
>   	lla.sll_ifindex = ifreq.ifr_ifindex;
>   	SAFE_BIND(sk, (struct sockaddr *)&lla, sizeof(struct sockaddr_ll));
>   


-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic

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Re: [LTP] [PATCH 0/2] pty: use correct protocol in pty04 based on line discipline

[Petr Vorel]

Hi Vasileios,

> Hi,

> during testing of the LTP pty test pty04, we observed intermittent
> failures caused by unexpected IPv6 packets being received.

> The test currently filters packets using ETH_P_ALL. As a result,
> packets with protocols other than the expected one (e.g. IPv6) may be
> received, leading to data corruption reports such as:

> TFAIL: Corrupt data (max 64 of 8191 bytes shown): data[0..64] =
> TFAIL: 60 00 00 00 00 24 00 01 00 00 00 00 00 00 00 00
> TFAIL: 00 00 00 00 00 00 00 00 ff 02 00 00 00 00 00 00
> TFAIL: 00 00 00 00 00 00 00 16 3a 00 05 02 00 00 01 00
> TFAIL: 8f 00 6e 8a 00 00 00 01 04 00 00 00 ff 02 00 00

nit: IMHO useful info, it'd be nice to have it in the commit itself (otherwise
it will be lost). But no need to repost.

Kind regards,
Petr

> This patch series addresses the issue by selecting the protocol based
> on the configured line discipline.

> Patch 1 adds a compatibility definition for ETH_P_CAN to the LAPI
> headers. Patch 2 updates pty04 to choose the appropriate protocol,
> avoiding reception of unrelated packets.

> Signed-off-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>

> Vasileios Almpanis (2):
>   add ETH_P_CAN compat macro to LAPI headers
>   pty04: use the correct protocol per line discipline to avoid extra
>     packets

>  include/lapi/if_ether.h      |  4 ++++
>  testcases/kernel/pty/pty04.c | 15 ++++++++++++++-
>  2 files changed, 18 insertions(+), 1 deletion(-)

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