From e9cc8bddaea3944fabfebb968bc88d603239beed Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 4 Mar 2009 14:53:30 +0800 Subject: netlink: Move netlink attribute parsing support to lib Netlink attribute parsing may be used even if CONFIG_NET is not set. Move it from net/netlink to lib and control its inclusion based on the new config symbol CONFIG_NLATTR, which is selected by CONFIG_NET. Signed-off-by: Geert Uytterhoeven Acked-by: David S. Miller Signed-off-by: Herbert Xu --- lib/Kconfig | 6 + lib/Makefile | 2 + lib/nlattr.c | 473 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 481 insertions(+) create mode 100644 lib/nlattr.c (limited to 'lib') diff --git a/lib/Kconfig b/lib/Kconfig index 03c2c24b908..cea9e30a88f 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -174,4 +174,10 @@ config DISABLE_OBSOLETE_CPUMASK_FUNCTIONS bool "Disable obsolete cpumask functions" if DEBUG_PER_CPU_MAPS depends on EXPERIMENTAL && BROKEN +# +# Netlink attribute parsing support is select'ed if needed +# +config NLATTR + bool + endmenu diff --git a/lib/Makefile b/lib/Makefile index 32b0e64ded2..b2c09da02ca 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -84,6 +84,8 @@ obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o obj-$(CONFIG_DYNAMIC_PRINTK_DEBUG) += dynamic_printk.o +obj-$(CONFIG_NLATTR) += nlattr.o + hostprogs-y := gen_crc32table clean-files := crc32table.h diff --git a/lib/nlattr.c b/lib/nlattr.c new file mode 100644 index 00000000000..56c3ce7fe29 --- /dev/null +++ b/lib/nlattr.c @@ -0,0 +1,473 @@ +/* + * NETLINK Netlink attributes + * + * Authors: Thomas Graf + * Alexey Kuznetsov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static u16 nla_attr_minlen[NLA_TYPE_MAX+1] __read_mostly = { + [NLA_U8] = sizeof(u8), + [NLA_U16] = sizeof(u16), + [NLA_U32] = sizeof(u32), + [NLA_U64] = sizeof(u64), + [NLA_NESTED] = NLA_HDRLEN, +}; + +static int validate_nla(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); + + switch (pt->type) { + case NLA_FLAG: + if (attrlen > 0) + return -ERANGE; + 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) + 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 + * + * 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(struct nlattr *head, int len, int maxtype, + const struct nla_policy *policy) +{ + struct nlattr *nla; + int rem, err; + + nla_for_each_attr(nla, head, len, rem) { + err = validate_nla(nla, maxtype, policy); + if (err < 0) + goto errout; + } + + err = 0; +errout: + return err; +} + +/** + * 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 accessable 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, struct nlattr *head, int len, + const struct nla_policy *policy) +{ + 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) + goto errout; + } + + tb[type] = nla; + } + } + + if (unlikely(rem > 0)) + printk(KERN_WARNING "netlink: %d bytes leftover after parsing " + "attributes.\n", rem); + + err = 0; +errout: + return err; +} + +/** + * 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(struct nlattr *head, int len, int attrtype) +{ + struct nlattr *nla; + int rem; + + nla_for_each_attr(nla, head, len, rem) + if (nla_type(nla) == attrtype) + return nla; + + return NULL; +} + +/** + * 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; +} + +/** + * 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); + + return minlen; +} + +/** + * 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; +} + +/** + * 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) + 1; + int d = nla_len(nla) - len; + + if (d == 0) + d = memcmp(nla_data(nla), str, len); + + return d; +} + +/** + * __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 = (struct nlattr *) 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; +} + +/** + * __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) +{ + void *start; + + start = skb_put(skb, NLA_ALIGN(attrlen)); + memset(start, 0, NLA_ALIGN(attrlen)); + + return start; +} + +/** + * 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); +} + +/** + * 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); +} + +/** + * __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); +} + +/** + * __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); +} + +/** + * 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; +} + +/** + * 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; +} + +/** + * 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; + + memcpy(skb_put(skb, attrlen), data, attrlen); + return 0; +} + +EXPORT_SYMBOL(nla_validate); +EXPORT_SYMBOL(nla_parse); +EXPORT_SYMBOL(nla_find); +EXPORT_SYMBOL(nla_strlcpy); +EXPORT_SYMBOL(__nla_reserve); +EXPORT_SYMBOL(__nla_reserve_nohdr); +EXPORT_SYMBOL(nla_reserve); +EXPORT_SYMBOL(nla_reserve_nohdr); +EXPORT_SYMBOL(__nla_put); +EXPORT_SYMBOL(__nla_put_nohdr); +EXPORT_SYMBOL(nla_put); +EXPORT_SYMBOL(nla_put_nohdr); +EXPORT_SYMBOL(nla_memcpy); +EXPORT_SYMBOL(nla_memcmp); +EXPORT_SYMBOL(nla_strcmp); +EXPORT_SYMBOL(nla_append); -- cgit v1.2.3-70-g09d2 From 908002161247e6e68c478052926b62d9a3d72418 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 11 Mar 2009 23:18:32 +0800 Subject: nlattr: Fix build error with NET off We moved the netlink attribute support from net to lib in order for it to be available for general consumption. However, parts of the code (the bits that we don't need :) really depends on NET because the target object is sk_buff. This patch fixes this by wrapping them in CONFIG_NET. Some EXPORTs have been moved to make this work. Tested-by: Geert Uytterhoeven Signed-off-by: Herbert Xu --- lib/nlattr.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'lib') diff --git a/lib/nlattr.c b/lib/nlattr.c index 56c3ce7fe29..80009a24e21 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -281,6 +281,7 @@ int nla_strcmp(const struct nlattr *nla, const char *str) return d; } +#ifdef CONFIG_NET /** * __nla_reserve - reserve room for attribute on the skb * @skb: socket buffer to reserve room on @@ -305,6 +306,7 @@ struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) return nla; } +EXPORT_SYMBOL(__nla_reserve); /** * __nla_reserve_nohdr - reserve room for attribute without header @@ -325,6 +327,7 @@ void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) return start; } +EXPORT_SYMBOL(__nla_reserve_nohdr); /** * nla_reserve - reserve room for attribute on the skb @@ -345,6 +348,7 @@ struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) return __nla_reserve(skb, attrtype, attrlen); } +EXPORT_SYMBOL(nla_reserve); /** * nla_reserve_nohdr - reserve room for attribute without header @@ -363,6 +367,7 @@ void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) return __nla_reserve_nohdr(skb, attrlen); } +EXPORT_SYMBOL(nla_reserve_nohdr); /** * __nla_put - Add a netlink attribute to a socket buffer @@ -382,6 +387,7 @@ void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, nla = __nla_reserve(skb, attrtype, attrlen); memcpy(nla_data(nla), data, attrlen); } +EXPORT_SYMBOL(__nla_put); /** * __nla_put_nohdr - Add a netlink attribute without header @@ -399,6 +405,7 @@ void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) 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 @@ -418,6 +425,7 @@ int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) __nla_put(skb, attrtype, attrlen, data); return 0; } +EXPORT_SYMBOL(nla_put); /** * nla_put_nohdr - Add a netlink attribute without header @@ -436,6 +444,7 @@ int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) __nla_put_nohdr(skb, attrlen, data); return 0; } +EXPORT_SYMBOL(nla_put_nohdr); /** * nla_append - Add a netlink attribute without header or padding @@ -454,20 +463,13 @@ int nla_append(struct sk_buff *skb, int attrlen, const void *data) memcpy(skb_put(skb, attrlen), data, attrlen); return 0; } +EXPORT_SYMBOL(nla_append); +#endif EXPORT_SYMBOL(nla_validate); EXPORT_SYMBOL(nla_parse); EXPORT_SYMBOL(nla_find); EXPORT_SYMBOL(nla_strlcpy); -EXPORT_SYMBOL(__nla_reserve); -EXPORT_SYMBOL(__nla_reserve_nohdr); -EXPORT_SYMBOL(nla_reserve); -EXPORT_SYMBOL(nla_reserve_nohdr); -EXPORT_SYMBOL(__nla_put); -EXPORT_SYMBOL(__nla_put_nohdr); -EXPORT_SYMBOL(nla_put); -EXPORT_SYMBOL(nla_put_nohdr); EXPORT_SYMBOL(nla_memcpy); EXPORT_SYMBOL(nla_memcmp); EXPORT_SYMBOL(nla_strcmp); -EXPORT_SYMBOL(nla_append); -- cgit v1.2.3-70-g09d2