kernel/linux.git/net/shaper, branch v7.1-rc5

net: shaper: rework the VALID marking (again)

2026-05-20T23:34:20+00:00

Recent commit changed the semantics from NOT_VALID to VALID. I didn't realize that the flags are not stored atomically with the entry in XArray. There's still a race of reader observing a VALID mark for a slot, getting interrupted, writer replacing the entry with a different one, reader continuing, fetching the entry which is now a different pointer than the pointer for which VALID was meant. The biggest consequence of this is that we may see a UAF since net_shaper_rollback() assumed that entries without VALID can be freed without observing RCU. Looks like the XArray marks are buying us nothing at this point. Let's convert the code to an explicit valid field. The smp_load_acquire() / smp_store_release() barriers are marginally cleaner. Reported-by: Sashiko Fixes: 93954b40f6a4 ("net-shapers: implement NL set and delete operations") Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260515221325.1685455-3-kuba@kernel.org Signed-off-by: Jakub Kicinski

net: shaper: annotate the data races

2026-05-20T23:34:20+00:00

As previously discussed we don't care about making the shaper state fully RCU-compliant because the hierarchy itself can't be dumped in one go over Netlink. Let's annotate the reads and writes to make that clear. The field-by-field assignments will also be useful for the next commit which adds explicit "valid" field (which we don't want to override with the current full struct assignment). Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260515221325.1685455-2-kuba@kernel.org Signed-off-by: Jakub Kicinski

net: shaper: reject QUEUE scope handle with missing id

2026-05-12T14:15:00+00:00

net_shaper_parse_handle() does not enforce that the user provides the handle ID. For NODE the ID defaults to UNSPEC for all other cases it defaults to 0. For NETDEV 0 is the only option. For QUEUE defaulting to 0 makes less intuitive sense. Specifically because the behavior should (IMHO) be the same for all cases where there may be more than one ID (QUEUE and NODE). We should either document this as intentional or reject. I picked the latter with no strong conviction. Fixes: 4b623f9f0f59 ("net-shapers: implement NL get operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-11-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: enforce singleton NETDEV scope with id 0

2026-05-12T14:15:00+00:00

The NETDEV scope represents a singleton root shaper in the per-device hierarchy. All code assumes NETDEV shapers have id 0: net_shaper_default_parent() hardcodes parent->id = 0 when returning the NETDEV parent for QUEUE/NODE children, and the UAPI documentation describes NETDEV scope as "the main shaper" (singular, not plural). Make sure we reject non-0 IDs. Fixes: 4b623f9f0f59 ("net-shapers: implement NL get operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-10-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: reject handle IDs exceeding internal bit-width

2026-05-12T14:15:00+00:00

net_shaper_parse_handle() reads the user-supplied handle ID via nla_get_u32(), accepting the full u32 range. However, the xarray key is built by net_shaper_handle_to_index() using FIELD_PREP(NET_SHAPER_ID_MASK, handle->id), where NET_SHAPER_ID_MASK is GENMASK(25, 0) - only 26 bits wide. FIELD_PREP silently masks off the upper bits at runtime. A user-supplied NODE id like 0x04000123 becomes id 0x123. Additionally, a user-supplied id equal to NET_SHAPER_ID_UNSPEC (0x03FFFFFF, which is NET_SHAPER_ID_MASK itself) would collide with the sentinel used internally by the group operation to signal "allocate a new NODE id". Reject user-supplied IDs >= NET_SHAPER_ID_MASK (i.e., >= 0x03FFFFFF) in the policy. Fixes: 4b623f9f0f59 ("net-shapers: implement NL get operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-9-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: fix undersized reply skb allocation in GROUP command

2026-05-12T14:14:59+00:00

net_shaper_group_send_reply() writes both the NET_SHAPER_A_IFINDEX attribute (via net_shaper_fill_binding()) and the nested NET_SHAPER_A_HANDLE attribute (via net_shaper_fill_handle()), but the reply skb at the call site in net_shaper_nl_group_doit() is allocated using net_shaper_handle_size(), which only accounts for the nested handle. The allocation is therefore short by nla_total_size(sizeof(u32)) (8 bytes) for the IFINDEX attribute. In practice the slab allocator rounds up the small allocation so the bug is latent, but the size accounting is wrong and could bite if the reply grew further. Introduce net_shaper_group_reply_size() that accounts for the full reply payload and use it both at the genlmsg_new() call site and in the defensive WARN_ONCE message. Fixes: 5d5d4700e75d ("net-shapers: implement NL group operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-7-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: set ret to -ENOMEM when genlmsg_new() fails in group_doit

2026-05-12T14:14:59+00:00

genlmsg_new() alloc failure path in net_shaper_nl_group_doit() forgets to set ret before jumping to error handling. Fixes: 5d5d4700e75d ("net-shapers: implement NL group operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-6-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: reject duplicate leaves in GROUP request

2026-05-12T14:14:59+00:00

net_shaper_nl_group_doit() does not deduplicate NET_SHAPER_A_LEAVES entries. When userspace supplies the same leaf handle twice, the same old-parent pointer lands twice in old_nodes[]. The cleanup loop double frees the parent. Of course the same parent may still be in old_nodes[] twice if we are moving multiple of its leaves. Note that this patch also implicitly fixes the fact that the i >= leaves_count path forgets to set ret. Fixes: 5d5d4700e75d ("net-shapers: implement NL group operation") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-4-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: fix trivial ordering issue in net_shaper_commit()

2026-05-12T14:14:59+00:00

We should update the entry before we mark it as valid. Fixes: 93954b40f6a4 ("net-shapers: implement NL set and delete operations") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-3-kuba@kernel.org Signed-off-by: Paolo Abeni

net: shaper: flip the polarity of the valid flag

2026-05-12T14:14:59+00:00

The usual way of inserting entries which are not yet fully ready into XArray is to have a VALID flag. The shaper code has a NOT_VALID flag. Since XArray code does not let us create entries with marks already set - the creation of entries is currently not atomic. Flip the polarity of the VALID flag. This closes the tiny race in net_shaper_pre_insert() of entries being created without the NOT_VALID flag. Fixes: 93954b40f6a4 ("net-shapers: implement NL set and delete operations") Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-2-kuba@kernel.org Signed-off-by: Paolo Abeni