linux-yocto/net/dsa
Jakob Unterwurzacher ba689e0893 net: dsa: microchip: linearize skb for tail-tagging switches
commit ba54bce747fa9e07896c1abd9b48545f7b4b31d2 upstream.

The pointer arithmentic for accessing the tail tag only works
for linear skbs.

For nonlinear skbs, it reads uninitialized memory inside the
skb headroom, essentially randomizing the tag. I have observed
it gets set to 6 most of the time.

Example where ksz9477_rcv thinks that the packet from port 1 comes from port 6
(which does not exist for the ksz9896 that's in use), dropping the packet.
Debug prints added by me (not included in this patch):

	[  256.645337] ksz9477_rcv:323 tag0=6
	[  256.645349] skb len=47 headroom=78 headlen=0 tailroom=0
	               mac=(64,14) mac_len=14 net=(78,0) trans=78
	               shinfo(txflags=0 nr_frags=1 gso(size=0 type=0 segs=0))
	               csum(0x0 start=0 offset=0 ip_summed=0 complete_sw=0 valid=0 level=0)
	               hash(0x0 sw=0 l4=0) proto=0x00f8 pkttype=1 iif=3
	               priority=0x0 mark=0x0 alloc_cpu=0 vlan_all=0x0
	               encapsulation=0 inner(proto=0x0000, mac=0, net=0, trans=0)
	[  256.645377] dev name=end1 feat=0x0002e10200114bb3
	[  256.645386] skb headroom: 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
	[  256.645395] skb headroom: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
	[  256.645403] skb headroom: 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
	[  256.645411] skb headroom: 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
	[  256.645420] skb headroom: 00000040: ff ff ff ff ff ff 00 1c 19 f2 e2 db 08 06
	[  256.645428] skb frag:     00000000: 00 01 08 00 06 04 00 01 00 1c 19 f2 e2 db 0a 02
	[  256.645436] skb frag:     00000010: 00 83 00 00 00 00 00 00 0a 02 a0 2f 00 00 00 00
	[  256.645444] skb frag:     00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
	[  256.645452] ksz_common_rcv:92 dsa_conduit_find_user returned NULL

Call skb_linearize before trying to access the tag.

This patch fixes ksz9477_rcv which is used by the ksz9896 I have at
hand, and also applies the same fix to ksz8795_rcv which seems to have
the same problem.

Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher@cherry.de>
CC: stable@vger.kernel.org
Fixes: 016e43a26b ("net: dsa: ksz: Add KSZ8795 tag code")
Fixes: 8b8010fb78 ("dsa: add support for Microchip KSZ tail tagging")
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/20250515072920.2313014-1-jakob.unterwurzacher@cherry.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-29 11:03:20 +02:00
..
conduit.c net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
conduit.h net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
devlink.c devlink: extend devlink_param *set pointer 2024-04-22 13:05:19 -07:00
devlink.h
dsa.c net: dsa: free routing table on probe failure 2025-04-25 10:47:46 +02:00
dsa.h net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
Kconfig net: dsa: vsc73xx: introduce tag 8021q for vsc73xx 2024-07-15 06:55:15 -07:00
Makefile net: dsa: vsc73xx: introduce tag 8021q for vsc73xx 2024-07-15 06:55:15 -07:00
netlink.c net: dsa: Rename IFLA_DSA_MASTER to IFLA_DSA_CONDUIT 2023-10-24 13:08:14 -07:00
netlink.h
port.c net: dsa: update the unicast MAC address when changing conduit 2024-06-10 13:48:06 +01:00
port.h net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
stubs.c net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub 2023-04-09 15:35:49 +01:00
switch.c net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
switch.h net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
tag_8021q.c net: dsa: avoid refcount warnings when ds->ops->tag_8021q_vlan_del() fails 2025-04-25 10:47:46 +02:00
tag_8021q.h net: dsa: tag_sja1105: refactor skb->dev assignment to dsa_tag_8021q_find_user() 2024-07-15 06:55:15 -07:00
tag_ar9331.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_brcm.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_dsa.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_gswip.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_hellcreek.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_ksz.c net: dsa: microchip: linearize skb for tail-tagging switches 2025-05-29 11:03:20 +02:00
tag_lan9303.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_mtk.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_none.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_ocelot_8021q.c net: dsa: tag_ocelot_8021q: fix broken reception 2024-12-19 18:13:21 +01:00
tag_ocelot.c net: mscc: ocelot: use ocelot_xmit_get_vlan_info() also for FDMA and register injection 2024-08-16 09:59:32 +01:00
tag_qca.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_rtl4_a.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_rtl8_4.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_rzn1_a5psw.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_sja1105.c net: dsa: tag_sja1105: refactor skb->dev assignment to dsa_tag_8021q_find_user() 2024-07-15 06:55:15 -07:00
tag_trailer.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag_vsc73xx_8021q.c net: dsa: vsc73xx: introduce tag 8021q for vsc73xx 2024-07-15 06:55:15 -07:00
tag_xrs700x.c net: fill in MODULE_DESCRIPTION()s for DSA tags 2024-01-05 08:06:19 -08:00
tag.c net: dsa: provide a software untagging function on RX for VLAN-aware bridges 2024-08-16 09:59:32 +01:00
tag.h net: dsa: restore dsa_software_vlan_untag() ability to operate on VLAN-untagged traffic 2024-12-27 14:02:05 +01:00
trace.c net: dsa: add trace points for FDB/MDB operations 2023-04-12 08:36:07 +01:00
trace.h tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
user.c net: dsa: refuse cross-chip mirroring operations 2024-10-09 19:41:35 -07:00
user.h net: dsa: update the unicast MAC address when changing conduit 2024-06-10 13:48:06 +01:00