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-rw-r--r--compat/backport-4.20.c379
1 files changed, 379 insertions, 0 deletions
diff --git a/compat/backport-4.20.c b/compat/backport-4.20.c
new file mode 100644
index 0000000..e26f3b5
--- /dev/null
+++ b/compat/backport-4.20.c
@@ -0,0 +1,379 @@
+/*
+ * Copyright (C) 2018 Intel Corporation
+ *
+ * Backport functionality introduced in Linux 4.20.
+ * This is basically upstream lib/nlattr.c.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <net/netlink.h>
+
+static const u8 nla_attr_len[NLA_TYPE_MAX+1] = {
+ [NLA_U8] = sizeof(u8),
+ [NLA_U16] = sizeof(u16),
+ [NLA_U32] = sizeof(u32),
+ [NLA_U64] = sizeof(u64),
+ [NLA_S8] = sizeof(s8),
+ [NLA_S16] = sizeof(s16),
+ [NLA_S32] = sizeof(s32),
+ [NLA_S64] = sizeof(s64),
+};
+
+static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = {
+ [NLA_U8] = sizeof(u8),
+ [NLA_U16] = sizeof(u16),
+ [NLA_U32] = sizeof(u32),
+ [NLA_U64] = sizeof(u64),
+ [NLA_MSECS] = sizeof(u64),
+ [NLA_NESTED] = NLA_HDRLEN,
+ [NLA_S8] = sizeof(s8),
+ [NLA_S16] = sizeof(s16),
+ [NLA_S32] = sizeof(s32),
+ [NLA_S64] = sizeof(s64),
+};
+
+static int validate_nla_bitfield32(const struct nlattr *nla,
+ const u32 *valid_flags_mask)
+{
+ const struct nla_bitfield32 *bf = nla_data(nla);
+
+ if (!valid_flags_mask)
+ return -EINVAL;
+
+ /*disallow invalid bit selector */
+ if (bf->selector & ~*valid_flags_mask)
+ return -EINVAL;
+
+ /*disallow invalid bit values */
+ if (bf->value & ~*valid_flags_mask)
+ return -EINVAL;
+
+ /*disallow valid bit values that are not selected*/
+ if (bf->value & ~bf->selector)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int nla_validate_array(const struct nlattr *head, int len, int maxtype,
+ const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ const struct nlattr *entry;
+ int rem;
+
+ nla_for_each_attr(entry, head, len, rem) {
+ int ret;
+
+ if (nla_len(entry) == 0)
+ continue;
+
+ if (nla_len(entry) < NLA_HDRLEN) {
+ NL_SET_ERR_MSG_ATTR(extack, entry,
+ "Array element too short");
+ return -ERANGE;
+ }
+
+ ret = nla_validate(nla_data(entry), nla_len(entry),
+ maxtype, policy, extack);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int nla_validate_int_range(const struct nla_policy *pt,
+ const struct nlattr *nla,
+ struct netlink_ext_ack *extack)
+{
+ bool validate_min, validate_max;
+ s64 value;
+
+ validate_min = pt->validation_type == NLA_VALIDATE_RANGE ||
+ pt->validation_type == NLA_VALIDATE_MIN;
+ validate_max = pt->validation_type == NLA_VALIDATE_RANGE ||
+ pt->validation_type == NLA_VALIDATE_MAX;
+
+ switch (pt->type) {
+ case NLA_U8:
+ value = nla_get_u8(nla);
+ break;
+ case NLA_U16:
+ value = nla_get_u16(nla);
+ break;
+ case NLA_U32:
+ value = nla_get_u32(nla);
+ break;
+ case NLA_S8:
+ value = nla_get_s8(nla);
+ break;
+ case NLA_S16:
+ value = nla_get_s16(nla);
+ break;
+ case NLA_S32:
+ value = nla_get_s32(nla);
+ break;
+ case NLA_S64:
+ value = nla_get_s64(nla);
+ break;
+ case NLA_U64:
+ /* treat this one specially, since it may not fit into s64 */
+ if ((validate_min && nla_get_u64(nla) < pt->min) ||
+ (validate_max && nla_get_u64(nla) > pt->max)) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "integer out of range");
+ return -ERANGE;
+ }
+ return 0;
+ default:
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ if ((validate_min && value < pt->min) ||
+ (validate_max && value > pt->max)) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "integer out of range");
+ return -ERANGE;
+ }
+
+ return 0;
+}
+
+static int validate_nla(const struct nlattr *nla, int maxtype,
+ const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ const struct nla_policy *pt;
+ int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
+ int err = -ERANGE;
+
+ if (type <= 0 || type > maxtype)
+ return 0;
+
+ pt = &policy[type];
+
+ BUG_ON(pt->type > NLA_TYPE_MAX);
+
+ if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) ||
+ (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) {
+ pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
+ current->comm, type);
+ }
+
+ switch (pt->type) {
+ case NLA_EXACT_LEN:
+ if (attrlen != pt->len)
+ goto out_err;
+ break;
+
+ case NLA_REJECT:
+ if (extack && pt->validation_data) {
+ NL_SET_BAD_ATTR(extack, nla);
+ extack->_msg = pt->validation_data;
+ return -EINVAL;
+ }
+ err = -EINVAL;
+ goto out_err;
+
+ case NLA_FLAG:
+ if (attrlen > 0)
+ goto out_err;
+ break;
+
+ case NLA_BITFIELD32:
+ if (attrlen != sizeof(struct nla_bitfield32))
+ goto out_err;
+
+ err = validate_nla_bitfield32(nla, pt->validation_data);
+ if (err)
+ goto out_err;
+ break;
+
+ case NLA_NUL_STRING:
+ if (pt->len)
+ minlen = min_t(int, attrlen, pt->len + 1);
+ else
+ minlen = attrlen;
+
+ if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) {
+ err = -EINVAL;
+ goto out_err;
+ }
+ /* fall through */
+
+ case NLA_STRING:
+ if (attrlen < 1)
+ goto out_err;
+
+ if (pt->len) {
+ char *buf = nla_data(nla);
+
+ if (buf[attrlen - 1] == '\0')
+ attrlen--;
+
+ if (attrlen > pt->len)
+ goto out_err;
+ }
+ break;
+
+ case NLA_BINARY:
+ if (pt->len && attrlen > pt->len)
+ goto out_err;
+ break;
+
+ case NLA_NESTED:
+ /* a nested attributes is allowed to be empty; if its not,
+ * it must have a size of at least NLA_HDRLEN.
+ */
+ if (attrlen == 0)
+ break;
+ if (attrlen < NLA_HDRLEN)
+ goto out_err;
+ if (pt->validation_data) {
+ err = nla_validate(nla_data(nla), nla_len(nla), pt->len,
+ pt->validation_data, extack);
+ if (err < 0) {
+ /*
+ * return directly to preserve the inner
+ * error message/attribute pointer
+ */
+ return err;
+ }
+ }
+ break;
+ case NLA_NESTED_ARRAY:
+ /* a nested array attribute is allowed to be empty; if its not,
+ * it must have a size of at least NLA_HDRLEN.
+ */
+ if (attrlen == 0)
+ break;
+ if (attrlen < NLA_HDRLEN)
+ goto out_err;
+ if (pt->validation_data) {
+ int err;
+
+ err = nla_validate_array(nla_data(nla), nla_len(nla),
+ pt->len, pt->validation_data,
+ extack);
+ if (err < 0) {
+ /*
+ * return directly to preserve the inner
+ * error message/attribute pointer
+ */
+ return err;
+ }
+ }
+ break;
+ default:
+ if (pt->len)
+ minlen = pt->len;
+ else if (pt->type != NLA_UNSPEC)
+ minlen = nla_attr_minlen[pt->type];
+
+ if (attrlen < minlen)
+ goto out_err;
+ }
+
+ /* further validation */
+ switch (pt->validation_type) {
+ case NLA_VALIDATE_NONE:
+ /* nothing to do */
+ break;
+ case NLA_VALIDATE_RANGE:
+ case NLA_VALIDATE_MIN:
+ case NLA_VALIDATE_MAX:
+ err = nla_validate_int_range(pt, nla, extack);
+ if (err)
+ return err;
+ break;
+ case NLA_VALIDATE_FUNCTION:
+ if (pt->validate) {
+ err = pt->validate(nla, extack);
+ if (err)
+ return err;
+ }
+ break;
+ }
+
+ return 0;
+out_err:
+ NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation");
+ return err;
+}
+
+int backport_nla_validate(const struct nlattr *head, int len, int maxtype,
+ const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ const struct nlattr *nla;
+ int rem;
+
+ nla_for_each_attr(nla, head, len, rem) {
+ int err = validate_nla(nla, maxtype, policy, extack);
+
+ if (err < 0)
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(backport_nla_validate);
+
+int backport_nla_policy_len(const struct nla_policy *p, int n)
+{
+ int i, len = 0;
+
+ for (i = 0; i < n; i++, p++) {
+ if (p->len)
+ len += nla_total_size(p->len);
+ else if (nla_attr_len[p->type])
+ len += nla_total_size(nla_attr_len[p->type]);
+ else if (nla_attr_minlen[p->type])
+ len += nla_total_size(nla_attr_minlen[p->type]);
+ }
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(backport_nla_policy_len);
+
+int backport_nla_parse(struct nlattr **tb, int maxtype,
+ const struct nlattr *head,
+ int len, const struct nla_policy *policy,
+ struct netlink_ext_ack *extack)
+{
+ const struct nlattr *nla;
+ int rem;
+
+ memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
+
+ nla_for_each_attr(nla, head, len, rem) {
+ u16 type = nla_type(nla);
+
+ if (type > 0 && type <= maxtype) {
+ if (policy) {
+ int err = validate_nla(nla, maxtype, policy,
+ extack);
+
+ if (err < 0)
+ return err;
+ }
+
+ tb[type] = (struct nlattr *)nla;
+ }
+ }
+
+ if (unlikely(rem > 0))
+ pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
+ rem, current->comm);
+
+ return 0;
+}
+EXPORT_SYMBOL(backport_nla_parse);
generated by cgit v1.2.3 (git 2.0.4) at 2024-04-26 15:55:40 +0000