kernel/tools/net/ynl/lib/ynl.c, branch linux-rolling-stable

tools: ynl-gen: validate nested arrays

2025-11-13T20:37:24Z

[ Upstream commit 1d99aa4ed707c5630a7a7f067c8818e19167e3a1 ] In nested arrays don't require that the intermediate attribute type should be a valid attribute type, it might just be zero or an incrementing index, it is often not even used. See include/net/netlink.h about NLA_NESTED_ARRAY: > The difference to NLA_NESTED is the structure: > NLA_NESTED has the nested attributes directly inside > while an array has the nested attributes at another > level down and the attribute types directly in the > nesting don't matter. Example based on include/uapi/linux/wireguard.h: > WGDEVICE_A_PEERS: NLA_NESTED > 0: NLA_NESTED > WGPEER_A_PUBLIC_KEY: NLA_EXACT_LEN, len WG_KEY_LEN > [..] > 0: NLA_NESTED > ... > ... Previous the check required that the nested type was valid in the parent attribute set, which in this case resolves to WGDEVICE_A_UNSPEC, which is YNL_PT_REJECT, and it took the early exit and returned YNL_PARSE_CB_ERROR. This patch renames the old nl_attr_validate() to __nl_attr_validate(), and creates a new inline function nl_attr_validate() to mimic the old one. The new __nl_attr_validate() takes the attribute type as an argument, so we can use it to validate attributes of a nested attribute, in the context of the parents attribute type, which in the above case is generated as: [WGDEVICE_A_PEERS] = { .name = "peers", .type = YNL_PT_NEST, .nest = &wireguard_wgpeer_nest, }, __nl_attr_validate() only checks if the attribute length is plausible for a given attribute type, so the .nest in the above example is not used. As the new inline function needs to be defined after ynl_attr_type(), then the definitions are moved down, so we avoid a forward declaration of ynl_attr_type(). Some other examples are NL80211_BAND_ATTR_FREQS (nest) and NL80211_ATTR_SUPPORTED_COMMANDS (u32) both in nl80211-user.c $ make -C tools/net/ynl/generated nl80211-user.c Signed-off-by: Asbjørn Sloth Tønnesen Reviewed-by: Jakub Kicinski Link: https://patch.msgid.link/20250915144301.725949-7-ast@fiberby.net Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

tools: ynl: submsg: reverse parse / error reporting

2025-05-16T23:32:06Z

Reverse parsing lets YNL convert bad and missing attr pointers from extack into a string like "missing attribute nest1.nest2.attr_name". It's a feature that's unique to YNL C AFAIU (even the Python YNL can't do nested reverse parsing). Add support for reverse-parsing of sub-messages. To simplify the logic and the code annotate the type policies with extra metadata. Mark the selectors and the messages with the information we need. We assume that key / selector always precedes the sub-message while parsing (and also if there are multiple sub-messages like in rt-link they are interleaved selector 1 ... submsg 1 ... selector 2 .. submsg 2, not selector 1 ... selector 2 ... submsg 1 ... submsg 2). The rt-link sample in a subsequent changes shows reverse parsing of sub-messages in action. Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250515231650.1325372-8-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl-gen: submsg: support parsing and rendering sub-messages

2025-05-16T23:32:06Z

Adjust parsing and rendering appropriately to make sub-messages work. Rendering is pretty trivial, as the submsg -> netlink conversion looks like rendering a nest in which only one attr was set. Only trick is that we use the enum value of the sub-message rather than the nest as the type, and effectively skip one layer of nesting. A real double nested struct would look like this: [SELECTOR] [SUBMSG] [NEST] [MSG1-ATTR] A submsg "is" the nest so by skipping I mean: [SELECTOR] [SUBMSG] [MSG1-ATTR] There is no extra validation in YNL if caller has set the selector matching the submsg type (e.g. link type = "macvlan" but the nest attrs are set to carry "veth"). Let the kernel handle that. Parsing side is a little more specialized as we need to render and insert a new kind of function which switches between what to parse based on the selector. But code isn't too complicated. Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250515231650.1325372-7-kuba@kernel.org Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-05-08T15:59:02Z

Cross-merge networking fixes after downstream PR (net-6.15-rc6). No conflicts. Adjacent changes: net/core/dev.c: 08e9f2d584c4 ("net: Lock netdevices during dev_shutdown") a82dc19db136 ("net: avoid potential race between netdev_get_by_index_lock() and netns switch") Signed-off-by: Jakub Kicinski

tools: ynl-gen: validate 0 len strings from kernel

2025-05-06T01:17:47Z

Strings from the kernel are guaranteed to be null terminated and ynl_attr_validate() checks for this. But it doesn't check if the string has a len of 0, which would cause problems when trying to access data[len - 1]. Fix this by checking that len is positive. Signed-off-by: David Wei Link: https://patch.msgid.link/20250503043050.861238-1-dw@davidwei.uk Signed-off-by: Jakub Kicinski

tools: ynl: allow fixed-header to be specified per op

2025-05-02T10:41:03Z

rtnetlink has variety of ops with different fixed headers. Detect that op fixed header is not the same as family one, and use sizeof() directly. For reverse parsing we need to pass the fixed header len along the policy (in the socket state). Reviewed-by: Donald Hunter Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20250429154704.2613851-13-kuba@kernel.org Signed-off-by: Paolo Abeni

tools: ynl: let classic netlink requests specify extra nlflags

2025-05-02T10:41:02Z

Classic netlink makes extensive use of flags. Support specifying them the same way as attributes are specified (using a helper), for example: rt_link_newlink_req_set_nlflags(req, NLM_F_CREATE | NLM_F_ECHO); Wrap the code up in a RenderInfo predicate. I think that some genetlink families may want this, too. It should be easy to add a spec property later. Reviewed-by: Donald Hunter Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20250429154704.2613851-5-kuba@kernel.org Signed-off-by: Paolo Abeni

tools: ynl: don't use genlmsghdr in classic netlink

2025-04-11T03:14:41Z

Make sure the codegen calls the right YNL lib helper to start the request based on family type. Classic netlink request must not include the genl header. Conversely don't expect genl headers in the responses. Reviewed-by: Jacob Keller Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250410014658.782120-10-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: support creating non-genl sockets

2025-04-11T03:14:41Z

Classic netlink has static family IDs specified in YAML, there is no family name -> ID lookup. Support providing the ID info to the library via the generated struct and make library use it. Since NETLINK_ROUTE is ID 0 we need an extra boolean to indicate classic_id is to be used. Reviewed-by: Jacob Keller Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250410014658.782120-8-kuba@kernel.org Signed-off-by: Jakub Kicinski

tools: ynl: c: correct reverse decode of empty attrs

2025-01-27T22:30:23Z

netlink reports which attribute was incorrect by sending back an attribute offset. Offset points to the address of struct nlattr, but to interpret the type we also need the nesting path. Attribute IDs have different meaning in different nests of the same message. Correct the condition for "is the offset within current attribute". ynl_attr_data_len() does not include the attribute header, so the end offset was off by 4 bytes. This means that we'd always skip over flags and empty nests. The devmem tests, for example, issues an invalid request with empty queue nests, resulting in the following error: YNL failed: Kernel error: missing attribute: .queues.ifindex The message is incorrect, "queues" nest does not have an "ifindex" attribute defined. With this fix we decend correctly into the nest: YNL failed: Kernel error: missing attribute: .queues.id Fixes: 86878f14d71a ("tools: ynl: user space helpers") Reviewed-by: Donald Hunter Link: https://patch.msgid.link/20250124012130.1121227-1-kuba@kernel.org Signed-off-by: Jakub Kicinski