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-rw-r--r--include/net/netlink.h6
-rw-r--r--include/uapi/linux/genetlink.h2
-rw-r--r--include/uapi/linux/netlink.h103
-rw-r--r--net/netlink/Makefile2
-rw-r--r--net/netlink/genetlink.c78
-rw-r--r--net/netlink/policy.c308
6 files changed, 498 insertions, 1 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h
index 557b67f1db99..c0411f14fb53 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -1933,4 +1933,10 @@ void nla_get_range_unsigned(const struct nla_policy *pt,
void nla_get_range_signed(const struct nla_policy *pt,
struct netlink_range_validation_signed *range);
+int netlink_policy_dump_start(const struct nla_policy *policy,
+ unsigned int maxtype,
+ unsigned long *state);
+bool netlink_policy_dump_loop(unsigned long *state);
+int netlink_policy_dump_write(struct sk_buff *skb, unsigned long state);
+
#endif
diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h
index 877f7fa95466..9c0636ec2286 100644
--- a/include/uapi/linux/genetlink.h
+++ b/include/uapi/linux/genetlink.h
@@ -48,6 +48,7 @@ enum {
CTRL_CMD_NEWMCAST_GRP,
CTRL_CMD_DELMCAST_GRP,
CTRL_CMD_GETMCAST_GRP, /* unused */
+ CTRL_CMD_GETPOLICY,
__CTRL_CMD_MAX,
};
@@ -62,6 +63,7 @@ enum {
CTRL_ATTR_MAXATTR,
CTRL_ATTR_OPS,
CTRL_ATTR_MCAST_GROUPS,
+ CTRL_ATTR_POLICY,
__CTRL_ATTR_MAX,
};
diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h
index 0a4d73317759..eac8a6a648ea 100644
--- a/include/uapi/linux/netlink.h
+++ b/include/uapi/linux/netlink.h
@@ -249,4 +249,107 @@ struct nla_bitfield32 {
__u32 selector;
};
+/*
+ * policy descriptions - it's specific to each family how this is used
+ * Normally, it should be retrieved via a dump inside another attribute
+ * specifying where it applies.
+ */
+
+/**
+ * enum netlink_attribute_type - type of an attribute
+ * @NL_ATTR_TYPE_INVALID: unused
+ * @NL_ATTR_TYPE_FLAG: flag attribute (present/not present)
+ * @NL_ATTR_TYPE_U8: 8-bit unsigned attribute
+ * @NL_ATTR_TYPE_U16: 16-bit unsigned attribute
+ * @NL_ATTR_TYPE_U32: 32-bit unsigned attribute
+ * @NL_ATTR_TYPE_U64: 64-bit unsigned attribute
+ * @NL_ATTR_TYPE_S8: 8-bit signed attribute
+ * @NL_ATTR_TYPE_S16: 16-bit signed attribute
+ * @NL_ATTR_TYPE_S32: 32-bit signed attribute
+ * @NL_ATTR_TYPE_S64: 64-bit signed attribute
+ * @NL_ATTR_TYPE_BINARY: binary data, min/max length may be specified
+ * @NL_ATTR_TYPE_STRING: string, min/max length may be specified
+ * @NL_ATTR_TYPE_NUL_STRING: NUL-terminated string,
+ * min/max length may be specified
+ * @NL_ATTR_TYPE_NESTED: nested, i.e. the content of this attribute
+ * consists of sub-attributes. The nested policy and maxtype
+ * inside may be specified.
+ * @NL_ATTR_TYPE_NESTED_ARRAY: nested array, i.e. the content of this
+ * attribute contains sub-attributes whose type is irrelevant
+ * (just used to separate the array entries) and each such array
+ * entry has attributes again, the policy for those inner ones
+ * and the corresponding maxtype may be specified.
+ * @NL_ATTR_TYPE_BITFIELD32: &struct nla_bitfield32 attribute
+ */
+enum netlink_attribute_type {
+ NL_ATTR_TYPE_INVALID,
+
+ NL_ATTR_TYPE_FLAG,
+
+ NL_ATTR_TYPE_U8,
+ NL_ATTR_TYPE_U16,
+ NL_ATTR_TYPE_U32,
+ NL_ATTR_TYPE_U64,
+
+ NL_ATTR_TYPE_S8,
+ NL_ATTR_TYPE_S16,
+ NL_ATTR_TYPE_S32,
+ NL_ATTR_TYPE_S64,
+
+ NL_ATTR_TYPE_BINARY,
+ NL_ATTR_TYPE_STRING,
+ NL_ATTR_TYPE_NUL_STRING,
+
+ NL_ATTR_TYPE_NESTED,
+ NL_ATTR_TYPE_NESTED_ARRAY,
+
+ NL_ATTR_TYPE_BITFIELD32,
+};
+
+/**
+ * enum netlink_policy_type_attr - policy type attributes
+ * @NL_POLICY_TYPE_ATTR_UNSPEC: unused
+ * @NL_POLICY_TYPE_ATTR_TYPE: type of the attribute,
+ * &enum netlink_attribute_type (U32)
+ * @NL_POLICY_TYPE_ATTR_MIN_VALUE_S: minimum value for signed
+ * integers (S64)
+ * @NL_POLICY_TYPE_ATTR_MAX_VALUE_S: maximum value for signed
+ * integers (S64)
+ * @NL_POLICY_TYPE_ATTR_MIN_VALUE_U: minimum value for unsigned
+ * integers (U64)
+ * @NL_POLICY_TYPE_ATTR_MAX_VALUE_U: maximum value for unsigned
+ * integers (U64)
+ * @NL_POLICY_TYPE_ATTR_MIN_LENGTH: minimum length for binary
+ * attributes, no minimum if not given (U32)
+ * @NL_POLICY_TYPE_ATTR_MAX_LENGTH: maximum length for binary
+ * attributes, no maximum if not given (U32)
+ * @NL_POLICY_TYPE_ATTR_POLICY_IDX: sub policy for nested and
+ * nested array types (U32)
+ * @NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE: maximum sub policy
+ * attribute for nested and nested array types, this can
+ * in theory be < the size of the policy pointed to by
+ * the index, if limited inside the nesting (U32)
+ * @NL_POLICY_TYPE_ATTR_BITFIELD32_MASK: valid mask for the
+ * bitfield32 type (U32)
+ * @NL_POLICY_TYPE_ATTR_PAD: pad attribute for 64-bit alignment
+ */
+enum netlink_policy_type_attr {
+ NL_POLICY_TYPE_ATTR_UNSPEC,
+ NL_POLICY_TYPE_ATTR_TYPE,
+ NL_POLICY_TYPE_ATTR_MIN_VALUE_S,
+ NL_POLICY_TYPE_ATTR_MAX_VALUE_S,
+ NL_POLICY_TYPE_ATTR_MIN_VALUE_U,
+ NL_POLICY_TYPE_ATTR_MAX_VALUE_U,
+ NL_POLICY_TYPE_ATTR_MIN_LENGTH,
+ NL_POLICY_TYPE_ATTR_MAX_LENGTH,
+ NL_POLICY_TYPE_ATTR_POLICY_IDX,
+ NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE,
+ NL_POLICY_TYPE_ATTR_BITFIELD32_MASK,
+ NL_POLICY_TYPE_ATTR_PAD,
+
+ /* keep last */
+ __NL_POLICY_TYPE_ATTR_MAX,
+ NL_POLICY_TYPE_ATTR_MAX = __NL_POLICY_TYPE_ATTR_MAX - 1
+};
+
#endif /* _UAPI__LINUX_NETLINK_H */
diff --git a/net/netlink/Makefile b/net/netlink/Makefile
index de42df7f0068..e05202708c90 100644
--- a/net/netlink/Makefile
+++ b/net/netlink/Makefile
@@ -3,7 +3,7 @@
# Makefile for the netlink driver.
#
-obj-y := af_netlink.o genetlink.o
+obj-y := af_netlink.o genetlink.o policy.o
obj-$(CONFIG_NETLINK_DIAG) += netlink_diag.o
netlink_diag-y := diag.o
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 9f357aa22b94..2f049692e012 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1043,6 +1043,80 @@ static int genl_ctrl_event(int event, const struct genl_family *family,
return 0;
}
+static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ const struct genl_family *rt;
+ unsigned int fam_id = cb->args[0];
+ int err;
+
+ if (!fam_id) {
+ struct nlattr *tb[CTRL_ATTR_MAX + 1];
+
+ err = genlmsg_parse(cb->nlh, &genl_ctrl, tb,
+ genl_ctrl.maxattr,
+ genl_ctrl.policy, cb->extack);
+ if (err)
+ return err;
+
+ if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
+ return -EINVAL;
+
+ if (tb[CTRL_ATTR_FAMILY_ID]) {
+ fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
+ } else {
+ rt = genl_family_find_byname(
+ nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
+ if (!rt)
+ return -ENOENT;
+ fam_id = rt->id;
+ }
+ }
+
+ rt = genl_family_find_byid(fam_id);
+ if (!rt)
+ return -ENOENT;
+
+ if (!rt->policy)
+ return -ENODATA;
+
+ err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]);
+ if (err)
+ return err;
+
+ while (netlink_policy_dump_loop(&cb->args[1])) {
+ void *hdr;
+ struct nlattr *nest;
+
+ hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, &genl_ctrl,
+ NLM_F_MULTI, CTRL_CMD_GETPOLICY);
+ if (!hdr)
+ goto nla_put_failure;
+
+ if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id))
+ goto nla_put_failure;
+
+ nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
+ if (!nest)
+ goto nla_put_failure;
+
+ if (netlink_policy_dump_write(skb, cb->args[1]))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+
+ genlmsg_end(skb, hdr);
+ continue;
+
+nla_put_failure:
+ genlmsg_cancel(skb, hdr);
+ break;
+ }
+
+ cb->args[0] = fam_id;
+ return skb->len;
+}
+
static const struct genl_ops genl_ctrl_ops[] = {
{
.cmd = CTRL_CMD_GETFAMILY,
@@ -1050,6 +1124,10 @@ static const struct genl_ops genl_ctrl_ops[] = {
.doit = ctrl_getfamily,
.dumpit = ctrl_dumpfamily,
},
+ {
+ .cmd = CTRL_CMD_GETPOLICY,
+ .dumpit = ctrl_dumppolicy,
+ },
};
static const struct genl_multicast_group genl_ctrl_groups[] = {
diff --git a/net/netlink/policy.c b/net/netlink/policy.c
new file mode 100644
index 000000000000..f6491853c797
--- /dev/null
+++ b/net/netlink/policy.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NETLINK Policy advertisement to userspace
+ *
+ * Authors: Johannes Berg <johannes@sipsolutions.net>
+ *
+ * Copyright 2019 Intel Corporation
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <net/netlink.h>
+
+#define INITIAL_POLICIES_ALLOC 10
+
+struct nl_policy_dump {
+ unsigned int policy_idx;
+ unsigned int attr_idx;
+ unsigned int n_alloc;
+ struct {
+ const struct nla_policy *policy;
+ unsigned int maxtype;
+ } policies[];
+};
+
+static int add_policy(struct nl_policy_dump **statep,
+ const struct nla_policy *policy,
+ unsigned int maxtype)
+{
+ struct nl_policy_dump *state = *statep;
+ unsigned int n_alloc, i;
+
+ if (!policy || !maxtype)
+ return 0;
+
+ for (i = 0; i < state->n_alloc; i++) {
+ if (state->policies[i].policy == policy)
+ return 0;
+
+ if (!state->policies[i].policy) {
+ state->policies[i].policy = policy;
+ state->policies[i].maxtype = maxtype;
+ return 0;
+ }
+ }
+
+ n_alloc = state->n_alloc + INITIAL_POLICIES_ALLOC;
+ state = krealloc(state, struct_size(state, policies, n_alloc),
+ GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ state->policies[state->n_alloc].policy = policy;
+ state->policies[state->n_alloc].maxtype = maxtype;
+ state->n_alloc = n_alloc;
+ *statep = state;
+
+ return 0;
+}
+
+static unsigned int get_policy_idx(struct nl_policy_dump *state,
+ const struct nla_policy *policy)
+{
+ unsigned int i;
+
+ for (i = 0; i < state->n_alloc; i++) {
+ if (state->policies[i].policy == policy)
+ return i;
+ }
+
+ WARN_ON_ONCE(1);
+ return -1;
+}
+
+int netlink_policy_dump_start(const struct nla_policy *policy,
+ unsigned int maxtype,
+ unsigned long *_state)
+{
+ struct nl_policy_dump *state;
+ unsigned int policy_idx;
+ int err;
+
+ /* also returns 0 if "*_state" is our ERR_PTR() end marker */
+ if (*_state)
+ return 0;
+
+ /*
+ * walk the policies and nested ones first, and build
+ * a linear list of them.
+ */
+
+ state = kzalloc(struct_size(state, policies, INITIAL_POLICIES_ALLOC),
+ GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+ state->n_alloc = INITIAL_POLICIES_ALLOC;
+
+ err = add_policy(&state, policy, maxtype);
+ if (err)
+ return err;
+
+ for (policy_idx = 0;
+ policy_idx < state->n_alloc && state->policies[policy_idx].policy;
+ policy_idx++) {
+ const struct nla_policy *policy;
+ unsigned int type;
+
+ policy = state->policies[policy_idx].policy;
+
+ for (type = 0;
+ type <= state->policies[policy_idx].maxtype;
+ type++) {
+ switch (policy[type].type) {
+ case NLA_NESTED:
+ case NLA_NESTED_ARRAY:
+ err = add_policy(&state,
+ policy[type].nested_policy,
+ policy[type].len);
+ if (err)
+ return err;
+ break;
+ default:
+ break;
+ }
+ }
+ }
+
+ *_state = (unsigned long)state;
+
+ return 0;
+}
+
+static bool netlink_policy_dump_finished(struct nl_policy_dump *state)
+{
+ return state->policy_idx >= state->n_alloc ||
+ !state->policies[state->policy_idx].policy;
+}
+
+bool netlink_policy_dump_loop(unsigned long *_state)
+{
+ struct nl_policy_dump *state = (void *)*_state;
+
+ if (IS_ERR(state))
+ return false;
+
+ if (netlink_policy_dump_finished(state)) {
+ kfree(state);
+ /* store end marker instead of freed state */
+ *_state = (unsigned long)ERR_PTR(-ENOENT);
+ return false;
+ }
+
+ return true;
+}
+
+int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state)
+{
+ struct nl_policy_dump *state = (void *)_state;
+ const struct nla_policy *pt;
+ struct nlattr *policy, *attr;
+ enum netlink_attribute_type type;
+ bool again;
+
+send_attribute:
+ again = false;
+
+ pt = &state->policies[state->policy_idx].policy[state->attr_idx];
+
+ policy = nla_nest_start(skb, state->policy_idx);
+ if (!policy)
+ return -ENOBUFS;
+
+ attr = nla_nest_start(skb, state->attr_idx);
+ if (!attr)
+ goto nla_put_failure;
+
+ switch (pt->type) {
+ default:
+ case NLA_UNSPEC:
+ case NLA_REJECT:
+ /* skip - use NLA_MIN_LEN to advertise such */
+ nla_nest_cancel(skb, policy);
+ again = true;
+ goto next;
+ case NLA_NESTED:
+ type = NL_ATTR_TYPE_NESTED;
+ /* fall through */
+ case NLA_NESTED_ARRAY:
+ if (pt->type == NLA_NESTED_ARRAY)
+ type = NL_ATTR_TYPE_NESTED_ARRAY;
+ if (pt->nested_policy && pt->len &&
+ (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_IDX,
+ get_policy_idx(state, pt->nested_policy)) ||
+ nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE,
+ pt->len)))
+ goto nla_put_failure;
+ break;
+ case NLA_U8:
+ case NLA_U16:
+ case NLA_U32:
+ case NLA_U64:
+ case NLA_MSECS: {
+ struct netlink_range_validation range;
+
+ if (pt->type == NLA_U8)
+ type = NL_ATTR_TYPE_U8;
+ else if (pt->type == NLA_U16)
+ type = NL_ATTR_TYPE_U16;
+ else if (pt->type == NLA_U32)
+ type = NL_ATTR_TYPE_U32;
+ else
+ type = NL_ATTR_TYPE_U64;
+
+ nla_get_range_unsigned(pt, &range);
+
+ if (nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MIN_VALUE_U,
+ range.min, NL_POLICY_TYPE_ATTR_PAD) ||
+ nla_put_u64_64bit(skb, NL_POLICY_TYPE_ATTR_MAX_VALUE_U,
+ range.max, NL_POLICY_TYPE_ATTR_PAD))
+ goto nla_put_failure;
+ break;
+ }
+ case NLA_S8:
+ case NLA_S16:
+ case NLA_S32:
+ case NLA_S64: {
+ struct netlink_range_validation_signed range;
+
+ if (pt->type == NLA_S8)
+ type = NL_ATTR_TYPE_S8;
+ else if (pt->type == NLA_S16)
+ type = NL_ATTR_TYPE_S16;
+ else if (pt->type == NLA_S32)
+ type = NL_ATTR_TYPE_S32;
+ else
+ type = NL_ATTR_TYPE_S64;
+
+ nla_get_range_signed(pt, &range);
+
+ if (nla_put_s64(skb, NL_POLICY_TYPE_ATTR_MIN_VALUE_S,
+ range.min, NL_POLICY_TYPE_ATTR_PAD) ||
+ nla_put_s64(skb, NL_POLICY_TYPE_ATTR_MAX_VALUE_S,
+ range.max, NL_POLICY_TYPE_ATTR_PAD))
+ goto nla_put_failure;
+ break;
+ }
+ case NLA_BITFIELD32:
+ type = NL_ATTR_TYPE_BITFIELD32;
+ if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_BITFIELD32_MASK,
+ pt->bitfield32_valid))
+ goto nla_put_failure;
+ break;
+ case NLA_EXACT_LEN:
+ type = NL_ATTR_TYPE_BINARY;
+ if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len) ||
+ nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH, pt->len))
+ goto nla_put_failure;
+ break;
+ case NLA_STRING:
+ case NLA_NUL_STRING:
+ case NLA_BINARY:
+ if (pt->type == NLA_STRING)
+ type = NL_ATTR_TYPE_STRING;
+ else if (pt->type == NLA_NUL_STRING)
+ type = NL_ATTR_TYPE_NUL_STRING;
+ else
+ type = NL_ATTR_TYPE_BINARY;
+ if (pt->len && nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MAX_LENGTH,
+ pt->len))
+ goto nla_put_failure;
+ break;
+ case NLA_MIN_LEN:
+ type = NL_ATTR_TYPE_BINARY;
+ if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_MIN_LENGTH, pt->len))
+ goto nla_put_failure;
+ break;
+ case NLA_FLAG:
+ type = NL_ATTR_TYPE_FLAG;
+ break;
+ }
+
+ if (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_TYPE, type))
+ goto nla_put_failure;
+
+ /* finish and move state to next attribute */
+ nla_nest_end(skb, attr);
+ nla_nest_end(skb, policy);
+
+next:
+ state->attr_idx += 1;
+ if (state->attr_idx > state->policies[state->policy_idx].maxtype) {
+ state->attr_idx = 0;
+ state->policy_idx++;
+ }
+
+ if (again) {
+ if (netlink_policy_dump_finished(state))
+ return -ENODATA;
+ goto send_attribute;
+ }
+
+ return 0;
+
+nla_put_failure:
+ nla_nest_cancel(skb, policy);
+ return -ENOBUFS;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-10 10:14:07 +0000