v4.19.13 snapshot.
diff --git a/lib/nlattr.c b/lib/nlattr.c
new file mode 100644
index 0000000..e335bca
--- /dev/null
+++ b/lib/nlattr.c
@@ -0,0 +1,697 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NETLINK Netlink attributes
+ *
+ * Authors: Thomas Graf <tgraf@suug.ch>
+ * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/skbuff.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <net/netlink.h>
+
+/* For these data types, attribute length should be exactly the given
+ * size. However, to maintain compatibility with broken commands, if the
+ * attribute length does not match the expected size a warning is emitted
+ * to the user that the command is sending invalid data and needs to be fixed.
+ */
+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,
+ u32 *valid_flags_allowed)
+{
+ const struct nla_bitfield32 *bf = nla_data(nla);
+ u32 *valid_flags_mask = valid_flags_allowed;
+
+ if (!valid_flags_allowed)
+ 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 validate_nla(const struct nlattr *nla, int maxtype,
+ const struct nla_policy *policy)
+{
+ const struct nla_policy *pt;
+ int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla);
+
+ 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]) {
+ pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n",
+ current->comm, type);
+ }
+
+ switch (pt->type) {
+ case NLA_FLAG:
+ if (attrlen > 0)
+ return -ERANGE;
+ break;
+
+ case NLA_BITFIELD32:
+ if (attrlen != sizeof(struct nla_bitfield32))
+ return -ERANGE;
+
+ return validate_nla_bitfield32(nla, pt->validation_data);
+
+ 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)
+ return -EINVAL;
+ /* fall through */
+
+ case NLA_STRING:
+ if (attrlen < 1)
+ return -ERANGE;
+
+ if (pt->len) {
+ char *buf = nla_data(nla);
+
+ if (buf[attrlen - 1] == '\0')
+ attrlen--;
+
+ if (attrlen > pt->len)
+ return -ERANGE;
+ }
+ break;
+
+ case NLA_BINARY:
+ if (pt->len && attrlen > pt->len)
+ return -ERANGE;
+ break;
+
+ case NLA_NESTED_COMPAT:
+ if (attrlen < pt->len)
+ return -ERANGE;
+ if (attrlen < NLA_ALIGN(pt->len))
+ break;
+ if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN)
+ return -ERANGE;
+ nla = nla_data(nla) + NLA_ALIGN(pt->len);
+ if (attrlen < NLA_ALIGN(pt->len) + NLA_HDRLEN + nla_len(nla))
+ return -ERANGE;
+ 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;
+ default:
+ if (pt->len)
+ minlen = pt->len;
+ else if (pt->type != NLA_UNSPEC)
+ minlen = nla_attr_minlen[pt->type];
+
+ if (attrlen < minlen)
+ return -ERANGE;
+ }
+
+ return 0;
+}
+
+/**
+ * nla_validate - Validate a stream of attributes
+ * @head: head of attribute stream
+ * @len: length of attribute stream
+ * @maxtype: maximum attribute type to be expected
+ * @policy: validation policy
+ * @extack: extended ACK report struct
+ *
+ * Validates all attributes in the specified attribute stream against the
+ * specified policy. Attributes with a type exceeding maxtype will be
+ * ignored. See documenation of struct nla_policy for more details.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int 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);
+
+ if (err < 0) {
+ if (extack)
+ extack->bad_attr = nla;
+ return err;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(nla_validate);
+
+/**
+ * nla_policy_len - Determin the max. length of a policy
+ * @policy: policy to use
+ * @n: number of policies
+ *
+ * Determines the max. length of the policy. It is currently used
+ * to allocated Netlink buffers roughly the size of the actual
+ * message.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int
+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(nla_policy_len);
+
+/**
+ * nla_parse - Parse a stream of attributes into a tb buffer
+ * @tb: destination array with maxtype+1 elements
+ * @maxtype: maximum attribute type to be expected
+ * @head: head of attribute stream
+ * @len: length of attribute stream
+ * @policy: validation policy
+ *
+ * Parses a stream of attributes and stores a pointer to each attribute in
+ * the tb array accessible via the attribute type. Attributes with a type
+ * exceeding maxtype will be silently ignored for backwards compatibility
+ * reasons. policy may be set to NULL if no validation is required.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int 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, err;
+
+ 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) {
+ err = validate_nla(nla, maxtype, policy);
+ if (err < 0) {
+ NL_SET_ERR_MSG_ATTR(extack, nla,
+ "Attribute failed policy validation");
+ goto errout;
+ }
+ }
+
+ 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);
+
+ err = 0;
+errout:
+ return err;
+}
+EXPORT_SYMBOL(nla_parse);
+
+/**
+ * nla_find - Find a specific attribute in a stream of attributes
+ * @head: head of attribute stream
+ * @len: length of attribute stream
+ * @attrtype: type of attribute to look for
+ *
+ * Returns the first attribute in the stream matching the specified type.
+ */
+struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype)
+{
+ const struct nlattr *nla;
+ int rem;
+
+ nla_for_each_attr(nla, head, len, rem)
+ if (nla_type(nla) == attrtype)
+ return (struct nlattr *)nla;
+
+ return NULL;
+}
+EXPORT_SYMBOL(nla_find);
+
+/**
+ * nla_strlcpy - Copy string attribute payload into a sized buffer
+ * @dst: where to copy the string to
+ * @nla: attribute to copy the string from
+ * @dstsize: size of destination buffer
+ *
+ * Copies at most dstsize - 1 bytes into the destination buffer.
+ * The result is always a valid NUL-terminated string. Unlike
+ * strlcpy the destination buffer is always padded out.
+ *
+ * Returns the length of the source buffer.
+ */
+size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
+{
+ size_t srclen = nla_len(nla);
+ char *src = nla_data(nla);
+
+ if (srclen > 0 && src[srclen - 1] == '\0')
+ srclen--;
+
+ if (dstsize > 0) {
+ size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen;
+
+ memset(dst, 0, dstsize);
+ memcpy(dst, src, len);
+ }
+
+ return srclen;
+}
+EXPORT_SYMBOL(nla_strlcpy);
+
+/**
+ * nla_strdup - Copy string attribute payload into a newly allocated buffer
+ * @nla: attribute to copy the string from
+ * @flags: the type of memory to allocate (see kmalloc).
+ *
+ * Returns a pointer to the allocated buffer or NULL on error.
+ */
+char *nla_strdup(const struct nlattr *nla, gfp_t flags)
+{
+ size_t srclen = nla_len(nla);
+ char *src = nla_data(nla), *dst;
+
+ if (srclen > 0 && src[srclen - 1] == '\0')
+ srclen--;
+
+ dst = kmalloc(srclen + 1, flags);
+ if (dst != NULL) {
+ memcpy(dst, src, srclen);
+ dst[srclen] = '\0';
+ }
+ return dst;
+}
+EXPORT_SYMBOL(nla_strdup);
+
+/**
+ * nla_memcpy - Copy a netlink attribute into another memory area
+ * @dest: where to copy to memcpy
+ * @src: netlink attribute to copy from
+ * @count: size of the destination area
+ *
+ * Note: The number of bytes copied is limited by the length of
+ * attribute's payload. memcpy
+ *
+ * Returns the number of bytes copied.
+ */
+int nla_memcpy(void *dest, const struct nlattr *src, int count)
+{
+ int minlen = min_t(int, count, nla_len(src));
+
+ memcpy(dest, nla_data(src), minlen);
+ if (count > minlen)
+ memset(dest + minlen, 0, count - minlen);
+
+ return minlen;
+}
+EXPORT_SYMBOL(nla_memcpy);
+
+/**
+ * nla_memcmp - Compare an attribute with sized memory area
+ * @nla: netlink attribute
+ * @data: memory area
+ * @size: size of memory area
+ */
+int nla_memcmp(const struct nlattr *nla, const void *data,
+ size_t size)
+{
+ int d = nla_len(nla) - size;
+
+ if (d == 0)
+ d = memcmp(nla_data(nla), data, size);
+
+ return d;
+}
+EXPORT_SYMBOL(nla_memcmp);
+
+/**
+ * nla_strcmp - Compare a string attribute against a string
+ * @nla: netlink string attribute
+ * @str: another string
+ */
+int nla_strcmp(const struct nlattr *nla, const char *str)
+{
+ int len = strlen(str);
+ char *buf = nla_data(nla);
+ int attrlen = nla_len(nla);
+ int d;
+
+ if (attrlen > 0 && buf[attrlen - 1] == '\0')
+ attrlen--;
+
+ d = attrlen - len;
+ if (d == 0)
+ d = memcmp(nla_data(nla), str, len);
+
+ return d;
+}
+EXPORT_SYMBOL(nla_strcmp);
+
+#ifdef CONFIG_NET
+/**
+ * __nla_reserve - reserve room for attribute on the skb
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it.
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
+{
+ struct nlattr *nla;
+
+ nla = skb_put(skb, nla_total_size(attrlen));
+ nla->nla_type = attrtype;
+ nla->nla_len = nla_attr_size(attrlen);
+
+ memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen));
+
+ return nla;
+}
+EXPORT_SYMBOL(__nla_reserve);
+
+/**
+ * __nla_reserve_64bit - reserve room for attribute on the skb and align it
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @padattr: attribute type for the padding
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it. It also ensure that this
+ * attribute will have a 64-bit aligned nla_data() area.
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
+ int attrlen, int padattr)
+{
+ if (nla_need_padding_for_64bit(skb))
+ nla_align_64bit(skb, padattr);
+
+ return __nla_reserve(skb, attrtype, attrlen);
+}
+EXPORT_SYMBOL(__nla_reserve_64bit);
+
+/**
+ * __nla_reserve_nohdr - reserve room for attribute without header
+ * @skb: socket buffer to reserve room on
+ * @attrlen: length of attribute payload
+ *
+ * Reserves room for attribute payload without a header.
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the payload.
+ */
+void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
+{
+ return skb_put_zero(skb, NLA_ALIGN(attrlen));
+}
+EXPORT_SYMBOL(__nla_reserve_nohdr);
+
+/**
+ * nla_reserve - reserve room for attribute on the skb
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it.
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen)
+{
+ if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
+ return NULL;
+
+ return __nla_reserve(skb, attrtype, attrlen);
+}
+EXPORT_SYMBOL(nla_reserve);
+
+/**
+ * nla_reserve_64bit - reserve room for attribute on the skb and align it
+ * @skb: socket buffer to reserve room on
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @padattr: attribute type for the padding
+ *
+ * Adds a netlink attribute header to a socket buffer and reserves
+ * room for the payload but does not copy it. It also ensure that this
+ * attribute will have a 64-bit aligned nla_data() area.
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ int padattr)
+{
+ size_t len;
+
+ if (nla_need_padding_for_64bit(skb))
+ len = nla_total_size_64bit(attrlen);
+ else
+ len = nla_total_size(attrlen);
+ if (unlikely(skb_tailroom(skb) < len))
+ return NULL;
+
+ return __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
+}
+EXPORT_SYMBOL(nla_reserve_64bit);
+
+/**
+ * nla_reserve_nohdr - reserve room for attribute without header
+ * @skb: socket buffer to reserve room on
+ * @attrlen: length of attribute payload
+ *
+ * Reserves room for attribute payload without a header.
+ *
+ * Returns NULL if the tailroom of the skb is insufficient to store
+ * the attribute payload.
+ */
+void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen)
+{
+ if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
+ return NULL;
+
+ return __nla_reserve_nohdr(skb, attrlen);
+}
+EXPORT_SYMBOL(nla_reserve_nohdr);
+
+/**
+ * __nla_put - Add a netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data)
+{
+ struct nlattr *nla;
+
+ nla = __nla_reserve(skb, attrtype, attrlen);
+ memcpy(nla_data(nla), data, attrlen);
+}
+EXPORT_SYMBOL(__nla_put);
+
+/**
+ * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ * @padattr: attribute type for the padding
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute header and payload.
+ */
+void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr)
+{
+ struct nlattr *nla;
+
+ nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr);
+ memcpy(nla_data(nla), data, attrlen);
+}
+EXPORT_SYMBOL(__nla_put_64bit);
+
+/**
+ * __nla_put_nohdr - Add a netlink attribute without header
+ * @skb: socket buffer to add attribute to
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * The caller is responsible to ensure that the skb provides enough
+ * tailroom for the attribute payload.
+ */
+void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
+{
+ void *start;
+
+ start = __nla_reserve_nohdr(skb, attrlen);
+ memcpy(start, data, attrlen);
+}
+EXPORT_SYMBOL(__nla_put_nohdr);
+
+/**
+ * nla_put - Add a netlink attribute to a socket buffer
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
+{
+ if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen)))
+ return -EMSGSIZE;
+
+ __nla_put(skb, attrtype, attrlen, data);
+ return 0;
+}
+EXPORT_SYMBOL(nla_put);
+
+/**
+ * nla_put_64bit - Add a netlink attribute to a socket buffer and align it
+ * @skb: socket buffer to add attribute to
+ * @attrtype: attribute type
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ * @padattr: attribute type for the padding
+ *
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
+ * the attribute header and payload.
+ */
+int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
+ const void *data, int padattr)
+{
+ size_t len;
+
+ if (nla_need_padding_for_64bit(skb))
+ len = nla_total_size_64bit(attrlen);
+ else
+ len = nla_total_size(attrlen);
+ if (unlikely(skb_tailroom(skb) < len))
+ return -EMSGSIZE;
+
+ __nla_put_64bit(skb, attrtype, attrlen, data, padattr);
+ return 0;
+}
+EXPORT_SYMBOL(nla_put_64bit);
+
+/**
+ * nla_put_nohdr - Add a netlink attribute without header
+ * @skb: socket buffer to add attribute to
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
+ * the attribute payload.
+ */
+int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data)
+{
+ if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
+ return -EMSGSIZE;
+
+ __nla_put_nohdr(skb, attrlen, data);
+ return 0;
+}
+EXPORT_SYMBOL(nla_put_nohdr);
+
+/**
+ * nla_append - Add a netlink attribute without header or padding
+ * @skb: socket buffer to add attribute to
+ * @attrlen: length of attribute payload
+ * @data: head of attribute payload
+ *
+ * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store
+ * the attribute payload.
+ */
+int nla_append(struct sk_buff *skb, int attrlen, const void *data)
+{
+ if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen)))
+ return -EMSGSIZE;
+
+ skb_put_data(skb, data, attrlen);
+ return 0;
+}
+EXPORT_SYMBOL(nla_append);
+#endif