// SPDX-License-Identifier: GPL-2.0-or-later
/*
* CALIPSO - Common Architecture Label IPv6 Security Option
*
* This is an implementation of the CALIPSO protocol as specified in
* RFC 5570.
*
* Authors: Paul Moore <[email protected]>
* Huw Davies <[email protected]>
*/
/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
* (c) Copyright Huw Davies <[email protected]>, 2015
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/jhash.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/calipso.h>
#include <linux/atomic.h>
#include <linux/bug.h>
#include <linux/unaligned.h>
#include <linux/crc-ccitt.h>
/* Maximium size of the calipso option including
* the two-byte TLV header.
*/
#define CALIPSO_OPT_LEN_MAX (2 + 252)
/* Size of the minimum calipso option including
* the two-byte TLV header.
*/
#define CALIPSO_HDR_LEN (2 + 8)
/* Maximium size of the calipso option including
* the two-byte TLV header and upto 3 bytes of
* leading pad and 7 bytes of trailing pad.
*/
#define CALIPSO_OPT_LEN_MAX_WITH_PAD (3 + CALIPSO_OPT_LEN_MAX + 7)
/* Maximium size of u32 aligned buffer required to hold calipso
* option. Max of 3 initial pad bytes starting from buffer + 3.
* i.e. the worst case is when the previous tlv finishes on 4n + 3.
*/
#define CALIPSO_MAX_BUFFER (6 + CALIPSO_OPT_LEN_MAX)
/* List of available DOI definitions */
static DEFINE_SPINLOCK(calipso_doi_list_lock);
static LIST_HEAD(calipso_doi_list);
/* Label mapping cache */
int calipso_cache_enabled = 1;
int calipso_cache_bucketsize = 10;
#define CALIPSO_CACHE_BUCKETBITS 7
#define CALIPSO_CACHE_BUCKETS BIT(CALIPSO_CACHE_BUCKETBITS)
#define CALIPSO_CACHE_REORDERLIMIT 10
struct calipso_map_cache_bkt {
spinlock_t lock;
u32 size;
struct list_head list;
};
struct calipso_map_cache_entry {
u32 hash;
unsigned char *key;
size_t key_len;
struct netlbl_lsm_cache *lsm_data;
u32 activity;
struct list_head list;
};
static struct calipso_map_cache_bkt *calipso_cache;
static void calipso_cache_invalidate(void);
static void calipso_doi_putdef(struct calipso_doi *doi_def);
/* Label Mapping Cache Functions
*/
/**
* calipso_cache_entry_free - Frees a cache entry
* @entry: the entry to free
*
* Description:
* This function frees the memory associated with a cache entry including the
* LSM cache data if there are no longer any users, i.e. reference count == 0.
*
*/
static void calipso_cache_entry_free(struct calipso_map_cache_entry *entry)
{
if (entry->lsm_data)
netlbl_secattr_cache_free(entry->lsm_data);
kfree(entry->key);
kfree(entry);
}
/**
* calipso_map_cache_hash - Hashing function for the CALIPSO cache
* @key: the hash key
* @key_len: the length of the key in bytes
*
* Description:
* The CALIPSO tag hashing function. Returns a 32-bit hash value.
*
*/
static u32 calipso_map_cache_hash(const unsigned char *key, u32 key_len)
{
return jhash(key, key_len, 0);
}
/**
* calipso_cache_init - Initialize the CALIPSO cache
*
* Description:
* Initializes the CALIPSO label mapping cache, this function should be called
* before any of the other functions defined in this file. Returns zero on
* success, negative values on error.
*
*/
static int __init calipso_cache_init(void)
{
u32 iter;
calipso_cache = kcalloc(CALIPSO_CACHE_BUCKETS,
sizeof(struct calipso_map_cache_bkt),
GFP_KERNEL);
if (!calipso_cache)
return -ENOMEM;
for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
spin_lock_init(&calipso_cache[iter].lock);
calipso_cache[iter].size = 0;
INIT_LIST_HEAD(&calipso_cache[iter].list);
}
return 0;
}
/**
* calipso_cache_invalidate - Invalidates the current CALIPSO cache
*
* Description:
* Invalidates and frees any entries in the CALIPSO cache. Returns zero on
* success and negative values on failure.
*
*/
static void calipso_cache_invalidate(void)
{
struct calipso_map_cache_entry *entry, *tmp_entry;
u32 iter;
for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
spin_lock_bh(&calipso_cache[iter].lock);
list_for_each_entry_safe(entry,
tmp_entry,
&calipso_cache[iter].list, list) {
list_del(&entry->list);
calipso_cache_entry_free(entry);
}
calipso_cache[iter].size = 0;
spin_unlock_bh(&calipso_cache[iter].lock);
}
}
/**
* calipso_cache_check - Check the CALIPSO cache for a label mapping
* @key: the buffer to check
* @key_len: buffer length in bytes
* @secattr: the security attribute struct to use
*
* Description:
* This function checks the cache to see if a label mapping already exists for
* the given key. If there is a match then the cache is adjusted and the
* @secattr struct is populated with the correct LSM security attributes. The
* cache is adjusted in the following manner if the entry is not already the
* first in the cache bucket:
*
* 1. The cache entry's activity counter is incremented
* 2. The previous (higher ranking) entry's activity counter is decremented
* 3. If the difference between the two activity counters is geater than
* CALIPSO_CACHE_REORDERLIMIT the two entries are swapped
*
* Returns zero on success, -ENOENT for a cache miss, and other negative values
* on error.
*
*/
static int calipso_cache_check(const unsigned char *key,
u32 key_len,
struct netlbl_lsm_secattr *secattr)
{
u32 bkt;
struct calipso_map_cache_entry *entry;
struct calipso_map_cache_entry *prev_entry = NULL;
u32 hash;
if (!calipso_cache_enabled)
return -ENOENT;
hash = calipso_map_cache_hash(key, key_len);
bkt = hash & (CALIPSO_CACHE_BUCKETS - 1);
spin_lock_bh(&calipso_cache[bkt].lock);
list_for_each_entry(entry, &calipso_cache[bkt].list, list) {
if (entry->hash == hash &&
entry->key_len == key_len &&
memcmp(entry->key, key, key_len) == 0) {
entry->activity += 1;
refcount_inc(&entry->lsm_data->refcount);
secattr->cache = entry->lsm_data;
secattr->flags |= NETLBL_SECATTR_CACHE;
secattr->type = NETLBL_NLTYPE_CALIPSO;
if (!prev_entry) {
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
}
if (prev_entry->activity > 0)
prev_entry->activity -= 1;
if (entry->activity > prev_entry->activity &&
entry->activity - prev_entry->activity >
CALIPSO_CACHE_REORDERLIMIT) {
__list_del(entry->list.prev, entry->list.next);
__list_add(&entry->list,
prev_entry->list.prev,
&prev_entry->list);
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
}
prev_entry = entry;
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return -ENOENT;
}
/**
* calipso_cache_add - Add an entry to the CALIPSO cache
* @calipso_ptr: the CALIPSO option
* @secattr: the packet's security attributes
*
* Description:
* Add a new entry into the CALIPSO label mapping cache. Add the new entry to
* head of the cache bucket's list, if the cache bucket is out of room remove
* the last entry in the list first. It is important to note that there is
* currently no checking for duplicate keys. Returns zero on success,
* negative values on failure. The key stored starts at calipso_ptr + 2,
* i.e. the type and length bytes are not stored, this corresponds to
* calipso_ptr[1] bytes of data.
*
*/
static int calipso_cache_add(const unsigned char *calipso_ptr,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val = -EPERM;
u32 bkt;
struct calipso_map_cache_entry *entry = NULL;
struct calipso_map_cache_entry *old_entry = NULL;
u32 calipso_ptr_len;
if (!calipso_cache_enabled || calipso_cache_bucketsize <= 0)
return 0;
calipso_ptr_len = calipso_ptr[1];
entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
if (!entry)
return -ENOMEM;
entry->key = kmemdup(calipso_ptr + 2, calipso_ptr_len, GFP_ATOMIC);
if (!entry->key) {
ret_val = -ENOMEM;
goto cache_add_failure;
}
entry->key_len = calipso_ptr_len;
entry->hash = calipso_map_cache_hash(calipso_ptr, calipso_ptr_len);
refcount_inc(&secattr->cache->refcount);
entry->lsm_data = secattr->cache;
bkt = entry->hash & (CALIPSO_CACHE_BUCKETS - 1);
spin_lock_bh(&calipso_cache[bkt].lock);
if (calipso_cache[bkt].size < calipso_cache_bucketsize) {
list_add(&entry->list, &calipso_cache[bkt].list);
calipso_cache[bkt].size += 1;
} else {
old_entry = list_entry(calipso_cache[bkt].list.prev,
struct calipso_map_cache_entry, list);
list_del(&old_entry->list);
list_add(&entry->list, &calipso_cache[bkt].list);
calipso_cache_entry_free(old_entry);
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
cache_add_failure:
if (entry)
calipso_cache_entry_free(entry);
return ret_val;
}
/* DOI List Functions
*/
/**
* calipso_doi_search - Searches for a DOI definition
* @doi: the DOI to search for
*
* Description:
* Search the DOI definition list for a DOI definition with a DOI value that
* matches @doi. The caller is responsible for calling rcu_read_[un]lock().
* Returns a pointer to the DOI definition on success and NULL on failure.
*/
static struct calipso_doi *calipso_doi_search(u32 doi)
{
struct calipso_doi *iter;
list_for_each_entry_rcu(iter, &calipso_doi_list, list)
if (iter->doi == doi && refcount_read(&iter->refcount))
return iter;
return NULL;
}
/**
* calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
* @doi_def: the DOI structure
* @audit_info: NetLabel audit information
*
* Description:
* The caller defines a new DOI for use by the CALIPSO engine and calls this
* function to add it to the list of acceptable domains. The caller must
* ensure that the mapping table specified in @doi_def->map meets all of the
* requirements of the mapping type (see calipso.h for details). Returns
* zero on success and non-zero on failure.
*
*/
static int calipso_doi_add(struct calipso_doi *doi_def,
struct netlbl_audit *audit_info)
{
int ret_val = -EINVAL;
u32 doi;
u32 doi_type;
struct audit_buffer *audit_buf;
doi = doi_def->doi;
doi_type = doi_def->type;
if (doi_def->doi == CALIPSO_DOI_UNKNOWN)
goto doi_add_return;
refcount_set(&doi_def->refcount, 1);
spin_lock(&calipso_doi_list_lock);
if (calipso_doi_search(doi_def->doi)) {
spin_unlock(&calipso_doi_list_lock);
ret_val = -EEXIST;
goto doi_add_return;
}
list_add_tail_rcu(&doi_def->list, &calipso_doi_list);
spin_unlock(&calipso_doi_list_lock);
ret_val = 0;
doi_add_return:
audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info);
if (audit_buf) {
const char *type_str;
switch (doi_type) {
case CALIPSO_MAP_PASS:
type_str = "pass";
break;
default:
type_str = "(unknown)";
}
audit_log_format(audit_buf,
" calipso_doi=%u calipso_type=%s res=%u",
doi, type_str, ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
return ret_val;
}
/**
* calipso_doi_free - Frees a DOI definition
* @doi_def: the DOI definition
*
* Description:
* This function frees all of the memory associated with a DOI definition.
*
*/
static void calipso_doi_free(struct calipso_doi *doi_def)
{
kfree(doi_def);
}
/**
* calipso_doi_free_rcu - Frees a DOI definition via the RCU pointer
* @entry: the entry's RCU field
*
* Description:
* This function is designed to be used as a callback to the call_rcu()
* function so that the memory allocated to the DOI definition can be released
* safely.
*
*/
static void calipso_doi_free_rcu(struct rcu_head *entry)
{
struct calipso_doi *doi_def;
doi_def = container_of(entry, struct calipso_doi, rcu);
calipso_doi_free(doi_def);
}
/**
* calipso_doi_remove - Remove an existing DOI from the CALIPSO protocol engine
* @doi: the DOI value
* @audit_info: NetLabel audit information
*
* Description:
* Removes a DOI definition from the CALIPSO engine. The NetLabel routines will
* be called to release their own LSM domain mappings as well as our own
* domain list. Returns zero on success and negative values on failure.
*
*/
static int calipso_doi_remove(u32 doi, struct netlbl_audit *audit_info)
{
int ret_val;
struct calipso_doi *doi_def;
struct audit_buffer *audit_buf;
spin_lock(&calipso_doi_list_lock);
doi_def = calipso_doi_search(doi);
if (!doi_def) {
spin_unlock(&calipso_doi_list_lock);
ret_val = -ENOENT;
goto doi_remove_return;
}
list_del_rcu(&doi_def->list);
spin_unlock(&calipso_doi_list_lock);
calipso_doi_putdef(doi_def);
ret_val = 0;
doi_remove_return:
audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_DEL, audit_info);
if (audit_buf) {
audit_log_format(audit_buf,
" calipso_doi=%u res=%u",
doi, ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
return ret_val;
}
/**
* calipso_doi_getdef - Returns a reference to a valid DOI definition
* @doi: the DOI value
*
* Description:
* Searches for a valid DOI definition and if one is found it is returned to
* the caller. Otherwise NULL is returned. The caller must ensure that
* calipso_doi_putdef() is called when the caller is done.
*
*/
static struct calipso_doi *calipso_doi_getdef(u32 doi)
{
struct calipso_doi *doi_def;
rcu_read_lock();
doi_def = calipso_doi_search(doi);
if (!doi_def)
goto doi_getdef_return;
if (!refcount_inc_not_zero(&doi_def->refcount))
doi_def = NULL;
doi_getdef_return:
rcu_read_unlock();
return doi_def;
}
/**
* calipso_doi_putdef - Releases a reference for the given DOI definition
* @doi_def: the DOI definition
*
* Description:
* Releases a DOI definition reference obtained from calipso_doi_getdef().
*
*/
static void calipso_doi_putdef(struct calipso_doi *doi_def)
{
if (!doi_def)
return;
if (!refcount_dec_and_test(&doi_def->refcount))
return;
calipso_cache_invalidate();
call_rcu(&doi_def->rcu, calipso_doi_free_rcu);
}
/**
* calipso_doi_walk - Iterate through the DOI definitions
* @skip_cnt: skip past this number of DOI definitions, updated
* @callback: callback for each DOI definition
* @cb_arg: argument for the callback function
*
* Description:
* Iterate over the DOI definition list, skipping the first @skip_cnt entries.
* For each entry call @callback, if @callback returns a negative value stop
* 'walking' through the list and return. Updates the value in @skip_cnt upon
* return. Returns zero on success, negative values on failure.
*
*/
static int calipso_doi_walk(u32 *skip_cnt,
int (*callback)(struct calipso_doi *doi_def,
void *arg),
void *cb_arg)
{
int ret_val = -ENOENT;
u32 doi_cnt = 0;
struct calipso_doi *iter_doi;
rcu_read_lock();
list_for_each_entry_rcu(iter_doi, &calipso_doi_list, list)
if (refcount_read(&iter_doi->refcount) > 0) {
if (doi_cnt++ < *skip_cnt)
continue;
ret_val = callback(iter_doi, cb_arg);
if (ret_val < 0) {
doi_cnt--;
goto doi_walk_return;
}
}
doi_walk_return:
rcu_read_unlock();
*skip_cnt = doi_cnt;
return ret_val;
}
/**
* calipso_validate - Validate a CALIPSO option
* @skb: the packet
* @option: the start of the option
*
* Description:
* This routine is called to validate a CALIPSO option.
* If the option is valid then %true is returned, otherwise
* %false is returned.
*
* The caller should have already checked that the length of the
* option (including the TLV header) is >= 10 and that the catmap
* length is consistent with the option length.
*
* We leave checks on the level and categories to the socket layer.
*/
bool calipso_validate(const struct sk_buff *skb, const unsigned char *option)
{
struct calipso_doi *doi_def;
bool ret_val;
u16 crc, len = option[1] + 2;
static const u8 zero[2];
/* The original CRC runs over the option including the TLV header
* with the CRC-16 field (at offset 8) zeroed out. */
crc = crc_ccitt(0xffff, option, 8);
crc = crc_ccitt(crc, zero, sizeof(zero));
if (len > 10)
crc = crc_ccitt(crc, option + 10, len - 10);
crc = ~crc;
if (option[8] != (crc & 0xff) || option[9] != ((crc >> 8) & 0xff))
return false;
rcu_read_lock();
doi_def = calipso_doi_search(get_unaligned_be32(option + 2));
ret_val = !!doi_def;
rcu_read_unlock();
return ret_val;
}
/**
* calipso_map_cat_hton - Perform a category mapping from host to network
* @doi_def: the DOI definition
* @secattr: the security attributes
* @net_cat: the zero'd out category bitmap in network/CALIPSO format
* @net_cat_len: the length of the CALIPSO bitmap in bytes
*
* Description:
* Perform a label mapping to translate a local MLS category bitmap to the
* correct CALIPSO bitmap using the given DOI definition. Returns the minimum
* size in bytes of the network bitmap on success, negative values otherwise.
*
*/
static int calipso_map_cat_hton(const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *net_cat,
u32 net_cat_len)
{
int spot = -1;
u32 net_spot_max = 0;
u32 net_clen_bits = net_cat_len * 8;
for (;;) {
spot = netlbl_catmap_walk(secattr->attr.mls.cat,
spot + 1);
if (spot < 0)
break;
if (spot >= net_clen_bits)
return -ENOSPC;
netlbl_bitmap_setbit(net_cat, spot, 1);
if (spot > net_spot_max)
net_spot_max = spot;
}
return (net_spot_max / 32 + 1) * 4;
}
/**
* calipso_map_cat_ntoh - Perform a category mapping from network to host
* @doi_def: the DOI definition
* @net_cat: the category bitmap in network/CALIPSO format
* @net_cat_len: the length of the CALIPSO bitmap in bytes
* @secattr: the security attributes
*
* Description:
* Perform a label mapping to translate a CALIPSO bitmap to the correct local
* MLS category bitmap using the given DOI definition. Returns zero on
* success, negative values on failure.
*
*/
static int calipso_map_cat_ntoh(const struct calipso_doi *doi_def,
const unsigned char *net_cat,
u32 net_cat_len,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
int spot = -1;
u32 net_clen_bits = net_cat_len * 8;
for (;;) {
spot = netlbl_bitmap_walk(net_cat,
net_clen_bits,
spot + 1,
1);
if (spot < 0)
return 0;
ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
spot,
GFP_ATOMIC);
if (ret_val != 0)
return ret_val;
}
return -EINVAL;
}
/**
* calipso_pad_write - Writes pad bytes in TLV format
* @buf: the buffer
* @offset: offset from start of buffer to write padding
* @count: number of pad bytes to write
*
* Description:
* Write @count bytes of TLV padding into @buffer starting at offset @offset.
* @count should be less than 8 - see RFC 4942.
*
*/
static int calipso_pad_write(unsigned char *buf, unsigned int offset,
unsigned int count)
{
if (WARN_ON_ONCE(count >= 8))
return -EINVAL;
switch (count) {
case 0:
break;
case 1:
buf[offset] = IPV6_TLV_PAD1;
break;
default:
buf[offset] = IPV6_TLV_PADN;
buf[offset + 1] = count - 2;
if (count > 2)
memset(buf + offset + 2, 0, count - 2);
break;
}
return 0;
}
/**
* calipso_genopt - Generate a CALIPSO option
* @buf: the option buffer
* @start: offset from which to write
* @buf_len: the size of opt_buf
* @doi_def: the CALIPSO DOI to use
* @secattr: the security attributes
*
* Description:
* Generate a CALIPSO option using the DOI definition and security attributes
* passed to the function. This also generates upto three bytes of leading
* padding that ensures that the option is 4n + 2 aligned. It returns the
* number of bytes written (including any initial padding).
*/
static int calipso_genopt(unsigned char *buf, u32 start, u32 buf_len,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u32 len, pad;
u16 crc;
static const unsigned char padding[4] = {2, 1, 0, 3};
unsigned char *calipso;
/* CALIPSO has 4n + 2 alignment */
pad = padding[start & 3];
if (buf_len <= start + pad + CALIPSO_HDR_LEN)
return -ENOSPC;
if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
return -EPERM;
len = CALIPSO_HDR_LEN;
if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
ret_val = calipso_map_cat_hton(doi_def,
secattr,
buf + start + pad + len,
buf_len - start - pad - len);
if (ret_val < 0)
return ret_val;
len += ret_val;
}
calipso_pad_write(buf, start, pad);
calipso = buf + start + pad;
calipso[0] = IPV6_TLV_CALIPSO;
calipso[1] = len - 2;
*(__be32 *)(calipso + 2) = htonl(doi_def->doi);
calipso[6] = (len - CALIPSO_HDR_LEN) / 4;
calipso[7] = secattr->attr.mls.lvl;
crc = ~crc_ccitt(0xffff, calipso, len);
calipso[8] = crc & 0xff;
calipso[9] = (crc >> 8) & 0xff;
return pad + len;
}
/* Hop-by-hop hdr helper functions
*/
/**
* calipso_opt_update - Replaces socket's hop options with a new set
* @sk: the socket
* @hop: new hop options
*
* Description:
* Replaces @sk's hop options with @hop. @hop may be NULL to leave
* the socket with no hop options.
*
*/
static int calipso_opt_update(struct sock *sk, struct ipv6_opt_hdr *hop)
{
struct ipv6_txoptions *old = txopt_get(inet6_sk(sk)), *txopts;
txopts = ipv6_renew_options(sk, old, IPV6_HOPOPTS, hop);
txopt_put(old);
if (IS_ERR(txopts))
return PTR_ERR(txopts);
txopts = ipv6_update_options(sk, txopts);
if (txopts) {
atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
txopt_put(txopts);
}
return 0;
}
/**
* calipso_tlv_len - Returns the length of the TLV
* @opt: the option header
* @offset: offset of the TLV within the header
*
* Description:
* Returns the length of the TLV option at offset @offset within
* the option header @opt. Checks that the entire TLV fits inside
* the option header, returns a negative value if this is not the case.
*/
static int calipso_tlv_len(struct ipv6_opt_hdr *opt, unsigned int offset)
{
unsigned char *tlv = (unsigned char *)opt;
unsigned int opt_len = ipv6_optlen(opt), tlv_len;
if (offset < sizeof(*opt) || offset >= opt_len)
return -EINVAL;
if (tlv[offset] == IPV6_TLV_PAD1)
return 1;
if (offset + 1 >= opt_len)
return -EINVAL;
tlv_len = tlv[offset + 1] + 2;
if (offset + tlv_len > opt_len)
return -EINVAL;
return tlv_len;
}
/**
* calipso_opt_find - Finds the CALIPSO option in an IPv6 hop options header
* @hop: the hop options header
* @start: on return holds the offset of any leading padding
* @end: on return holds the offset of the first non-pad TLV after CALIPSO
*
* Description:
* Finds the space occupied by a CALIPSO option (including any leading and
* trailing padding).
*
* If a CALIPSO option exists set @start and @end to the
* offsets within @hop of the start of padding before the first
* CALIPSO option and the end of padding after the first CALIPSO
* option. In this case the function returns 0.
*
* In the absence of a CALIPSO option, @start and @end will be
* set to the start and end of any trailing padding in the header.
* This is useful when appending a new option, as the caller may want
* to overwrite some of this padding. In this case the function will
* return -ENOENT.
*/
static int calipso_opt_find(struct ipv6_opt_hdr *hop, unsigned int *start,
unsigned int *end)
{
int ret_val = -ENOENT, tlv_len;
unsigned int opt_len, offset, offset_s = 0, offset_e = 0;
unsigned char *opt = (unsigned char *)hop;
opt_len = ipv6_optlen(hop);
offset = sizeof(*hop);
while (offset < opt_len) {
tlv_len = calipso_tlv_len(hop, offset);
if (tlv_len < 0)
return tlv_len;
switch (opt[offset]) {
case IPV6_TLV_PAD1:
case IPV6_TLV_PADN:
if (offset_e)
offset_e = offset;
break;
case IPV6_TLV_CALIPSO:
ret_val = 0;
offset_e = offset;
break;
default:
if (offset_e == 0)
offset_s = offset;
else
goto out;
}
offset += tlv_len;
}
out:
if (offset_s)
*start = offset_s + calipso_tlv_len(hop, offset_s);
else
*start = sizeof(*hop);
if (offset_e)
*end = offset_e + calipso_tlv_len(hop, offset_e);
else
*end = opt_len;
return ret_val;
}
/**
* calipso_opt_insert - Inserts a CALIPSO option into an IPv6 hop opt hdr
* @hop: the original hop options header
* @doi_def: the CALIPSO DOI to use
* @secattr: the specific security attributes of the socket
*
* Description:
* Creates a new hop options header based on @hop with a
* CALIPSO option added to it. If @hop already contains a CALIPSO
* option this is overwritten, otherwise the new option is appended
* after any existing options. If @hop is NULL then the new header
* will contain just the CALIPSO option and any needed padding.
*
*/
static struct ipv6_opt_hdr *
calipso_opt_insert(struct ipv6_opt_hdr *hop,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
unsigned int start, end, buf_len, pad, hop_len;
struct ipv6_opt_hdr *new;
int ret_val;
if (hop) {
hop_len = ipv6_optlen(hop);
ret_val = calipso_opt_find(hop, &start, &end);
if (ret_val && ret_val != -ENOENT)
return ERR_PTR(ret_val);
} else {
hop_len = 0;
start = sizeof(*hop);
end = 0;
}
buf_len = hop_len + start - end + CALIPSO_OPT_LEN_MAX_WITH_PAD;
new = kzalloc(buf_len, GFP_ATOMIC);
if (!new)
return ERR_PTR(-ENOMEM);
if (start > sizeof(*hop))
memcpy(new, hop, start);
ret_val = calipso_genopt((unsigned char *)new, start, buf_len, doi_def,
secattr);
if (ret_val < 0) {
kfree(new);
return ERR_PTR(ret_val);
}
buf_len = start + ret_val;
/* At this point buf_len aligns to 4n, so (buf_len & 4) pads to 8n */
pad = ((buf_len & 4) + (end & 7)) & 7;
calipso_pad_write((unsigned char *)new, buf_len, pad);
buf_len += pad;
if (end != hop_len) {
memcpy((char *)new + buf_len, (char *)hop + end, hop_len - end);
buf_len += hop_len - end;
}
new->nexthdr = 0;
new->hdrlen = buf_len / 8 - 1;
return new;
}
/**
* calipso_opt_del - Removes the CALIPSO option from an option header
* @hop: the original header
* @new: the new header
*
* Description:
* Creates a new header based on @hop without any CALIPSO option. If @hop
* doesn't contain a CALIPSO option it returns -ENOENT. If @hop contains
* no other non-padding options, it returns zero with @new set to NULL.
* Otherwise it returns zero, creates a new header without the CALIPSO
* option (and removing as much padding as possible) and returns with
* @new set to that header.
*
*/
static int calipso_opt_del(struct ipv6_opt_hdr *hop,
struct ipv6_opt_hdr **new)
{
int ret_val;
unsigned int start, end, delta, pad, hop_len;
ret_val = calipso_opt_find(hop, &start, &end);
if (ret_val)
return ret_val;
hop_len = ipv6_optlen(hop);
if (start == sizeof(*hop) && end == hop_len) {
/* There's no other option in the header so return NULL */
*new = NULL;
return 0;
}
delta = (end - start) & ~7;
*new = kzalloc(hop_len - delta, GFP_ATOMIC);
if (!*new)
return -ENOMEM;
memcpy(*new, hop, start);
(*new)->hdrlen -= delta / 8;
pad = (end - start) & 7;
calipso_pad_write((unsigned char *)*new, start, pad);
if (end != hop_len)
memcpy((char *)*new + start + pad, (char *)hop + end,
hop_len - end);
return 0;
}
/**
* calipso_opt_getattr - Get the security attributes from a memory block
* @calipso: the CALIPSO option
* @secattr: the security attributes
*
* Description:
* Inspect @calipso and return the security attributes in @secattr.
* Returns zero on success and negative values on failure.
*
*/
static int calipso_opt_getattr(const unsigned char *calipso,
struct netlbl_lsm_secattr *secattr)
{
int ret_val = -ENOMSG;
u32 doi, len = calipso[1], cat_len = calipso[6] * 4;
struct calipso_doi *doi_def;
if (cat_len + 8 > len)
return -EINVAL;
if (calipso_cache_check(calipso + 2, calipso[1], secattr) == 0)
return 0;
doi = get_unaligned_be32(calipso + 2);
rcu_read_lock();
doi_def = calipso_doi_search(doi);
if (!doi_def)
goto getattr_return;
secattr->attr.mls.lvl = calipso[7];
secattr->flags |= NETLBL_SECATTR_MLS_LVL;
if (cat_len) {
ret_val = calipso_map_cat_ntoh(doi_def,
calipso + 10,
cat_len,
secattr);
if (ret_val != 0) {
netlbl_catmap_free(secattr->attr.mls.cat);
goto getattr_return;
}
if (secattr->attr.mls.cat)
secattr->flags |= NETLBL_SECATTR_MLS_CAT;
}
secattr->type = NETLBL_NLTYPE_CALIPSO;
getattr_return:
rcu_read_unlock();
return ret_val;
}
/* sock functions.
*/
/**
* calipso_sock_getattr - Get the security attributes from a sock
* @sk: the sock
* @secattr: the security attributes
*
* Description:
* Query @sk to see if there is a CALIPSO option attached to the sock and if
* there is return the CALIPSO security attributes in @secattr. This function
* requires that @sk be locked, or privately held, but it does not do any
* locking itself. Returns zero on success and negative values on failure.
*
*/
static int calipso_sock_getattr(struct sock *sk,
struct netlbl_lsm_secattr *secattr)
{
struct ipv6_opt_hdr *hop;
int opt_len, len, ret_val = -ENOMSG, offset;
unsigned char *opt;
struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
if (!txopts || !txopts->hopopt)
goto done;
hop = txopts->hopopt;
opt = (unsigned char *)hop;
opt_len = ipv6_optlen(hop);
offset = sizeof(*hop);
while (offset < opt_len) {
len = calipso_tlv_len(hop, offset);
if (len < 0) {
ret_val = len;
goto done;
}
switch (opt[offset]) {
case IPV6_TLV_CALIPSO:
if (len < CALIPSO_HDR_LEN)
ret_val = -EINVAL;
else
ret_val = calipso_opt_getattr(&opt[offset],
secattr);
goto done;
default:
offset += len;
break;
}
}
done:
txopt_put(txopts);
return ret_val;
}
/**
* calipso_sock_setattr - Add a CALIPSO option to a socket
* @sk: the socket
* @doi_def: the CALIPSO DOI to use
* @secattr: the specific security attributes of the socket
*
* Description:
* Set the CALIPSO option on the given socket using the DOI definition and
* security attributes passed to the function. This function requires
* exclusive access to @sk, which means it either needs to be in the
* process of being created or locked. Returns zero on success and negative
* values on failure.
*
*/
static int calipso_sock_setattr(struct sock *sk,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
struct ipv6_opt_hdr *old, *new;
struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
old = NULL;
if (txopts)
old = txopts->hopopt;
new = calipso_opt_insert(old, doi_def, secattr);
txopt_put(txopts);
if (IS_ERR(new))
return PTR_ERR(new);
ret_val = calipso_opt_update(sk, new);
kfree(new);
return ret_val;
}
/**
* calipso_sock_delattr - Delete the CALIPSO option from a socket
* @sk: the socket
*
* Description:
* Removes the CALIPSO option from a socket, if present.
*
*/
static void calipso_sock_delattr(struct sock *sk)
{
struct ipv6_opt_hdr *new_hop;
struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
if (!txopts || !txopts->hopopt)
goto done;
if (calipso_opt_del(txopts->hopopt, &new_hop))
goto done;
calipso_opt_update(sk, new_hop);
kfree(new_hop);
done:
txopt_put(txopts);
}
/* request sock functions.
*/
/**
* calipso_req_setattr - Add a CALIPSO option to a connection request socket
* @req: the connection request socket
* @doi_def: the CALIPSO DOI to use
* @secattr: the specific security attributes of the socket
*
* Description:
* Set the CALIPSO option on the given socket using the DOI definition and
* security attributes passed to the function. Returns zero on success and
* negative values on failure.
*
*/
static int calipso_req_setattr(struct request_sock *req,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
struct ipv6_txoptions *txopts;
struct inet_request_sock *req_inet = inet_rsk(req);
struct ipv6_opt_hdr *old, *new;
struct sock *sk = sk_to_full_sk(req_to_sk(req));
if (req_inet->ipv6_opt && req_inet->ipv6_opt->hopopt)
old = req_inet->ipv6_opt->hopopt;
else
old = NULL;
new = calipso_opt_insert(old, doi_def, secattr);
if (IS_ERR(new))
return PTR_ERR(new);
txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
kfree(new);
if (IS_ERR(txopts))
return PTR_ERR(txopts);
txopts = xchg(&req_inet->ipv6_opt, txopts);
if (txopts) {
atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
txopt_put(txopts);
}
return 0;
}
/**
* calipso_req_delattr - Delete the CALIPSO option from a request socket
* @req: the request socket
*
* Description:
* Removes the CALIPSO option from a request socket, if present.
*
*/
static void calipso_req_delattr(struct request_sock *req)
{
struct inet_request_sock *req_inet = inet_rsk(req);
struct ipv6_opt_hdr *new;
struct ipv6_txoptions *txopts;
struct sock *sk = sk_to_full_sk(req_to_sk(req));
if (!req_inet->ipv6_opt || !req_inet->ipv6_opt->hopopt)
return;
if (calipso_opt_del(req_inet->ipv6_opt->hopopt, &new))
return; /* Nothing to do */
txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
if (!IS_ERR(txopts)) {
txopts = xchg(&req_inet->ipv6_opt, txopts);
if (txopts) {
atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
txopt_put(txopts);
}
}
kfree(new);
}
/* skbuff functions.
*/
/**
* calipso_skbuff_optptr - Find the CALIPSO option in the packet
* @skb: the packet
*
* Description:
* Parse the packet's IP header looking for a CALIPSO option. Returns a pointer
* to the start of the CALIPSO option on success, NULL if one if not found.
*
*/
static unsigned char *calipso_skbuff_optptr(const struct sk_buff *skb)
{
const struct ipv6hdr *ip6_hdr = ipv6_hdr(skb);
int offset;
if (ip6_hdr->nexthdr != NEXTHDR_HOP)
return NULL;
offset = ipv6_find_tlv(skb, sizeof(*ip6_hdr), IPV6_TLV_CALIPSO);
if (offset >= 0)
return (unsigned char *)ip6_hdr + offset;
return NULL;
}
/**
* calipso_skbuff_setattr - Set the CALIPSO option on a packet
* @skb: the packet
* @doi_def: the CALIPSO DOI to use
* @secattr: the security attributes
*
* Description:
* Set the CALIPSO option on the given packet based on the security attributes.
* Returns a pointer to the IP header on success and NULL on failure.
*
*/
static int calipso_skbuff_setattr(struct sk_buff *skb,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
struct ipv6hdr *ip6_hdr;
struct ipv6_opt_hdr *hop;
unsigned char buf[CALIPSO_MAX_BUFFER];
int len_delta, new_end, pad, payload;
unsigned int start, end;
ip6_hdr = ipv6_hdr(skb);
if (ip6_hdr->nexthdr == NEXTHDR_HOP) {
hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
ret_val = calipso_opt_find(hop, &start, &end);
if (ret_val && ret_val != -ENOENT)
return ret_val;
} else {
start = 0;
end = 0;
}
memset(buf, 0, sizeof(buf));
ret_val = calipso_genopt(buf, start & 3, sizeof(buf), doi_def, secattr);
if (ret_val < 0)
return ret_val;
new_end = start + ret_val;
/* At this point new_end aligns to 4n, so (new_end & 4) pads to 8n */
pad = ((new_end & 4) + (end & 7)) & 7;
len_delta = new_end - (int)end + pad;
ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
if (ret_val < 0)
return ret_val;
ip6_hdr = ipv6_hdr(skb); /* Reset as skb_cow() may have moved it */
if (len_delta) {
if (len_delta > 0)
skb_push(skb, len_delta);
else
skb_pull(skb, -len_delta);
memmove((char *)ip6_hdr - len_delta, ip6_hdr,
sizeof(*ip6_hdr) + start);
skb_reset_network_header(skb);
ip6_hdr = ipv6_hdr(skb);
payload = ntohs(ip6_hdr->payload_len);
ip6_hdr->payload_len = htons(payload + len_delta);
}
hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
if (start == 0) {
struct ipv6_opt_hdr *new_hop = (struct ipv6_opt_hdr *)buf;
new_hop->nexthdr = ip6_hdr->nexthdr;
new_hop->hdrlen = len_delta / 8 - 1;
ip6_hdr->nexthdr = NEXTHDR_HOP;
} else {
hop->hdrlen += len_delta / 8;
}
memcpy((char *)hop + start, buf + (start & 3), new_end - start);
calipso_pad_write((unsigned char *)hop, new_end, pad);
return 0;
}
/**
* calipso_skbuff_delattr - Delete any CALIPSO options from a packet
* @skb: the packet
*
* Description:
* Removes any and all CALIPSO options from the given packet. Returns zero on
* success, negative values on failure.
*
*/
static int calipso_skbuff_delattr(struct sk_buff *skb)
{
int ret_val;
struct ipv6hdr *ip6_hdr;
struct ipv6_opt_hdr *old_hop;
u32 old_hop_len, start = 0, end = 0, delta, size, pad;
if (!calipso_skbuff_optptr(skb))
return 0;
/* since we are changing the packet we should make a copy */
ret_val = skb_cow(skb, skb_headroom(skb));
if (ret_val < 0)
return ret_val;
ip6_hdr = ipv6_hdr(skb);
old_hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
old_hop_len = ipv6_optlen(old_hop);
ret_val = calipso_opt_find(old_hop, &start, &end);
if (ret_val)
return ret_val;
if (start == sizeof(*old_hop) && end == old_hop_len) {
/* There's no other option in the header so we delete
* the whole thing. */
delta = old_hop_len;
size = sizeof(*ip6_hdr);
ip6_hdr->nexthdr = old_hop->nexthdr;
} else {
delta = (end - start) & ~7;
if (delta)
old_hop->hdrlen -= delta / 8;
pad = (end - start) & 7;
size = sizeof(*ip6_hdr) + start + pad;
calipso_pad_write((unsigned char *)old_hop, start, pad);
}
if (delta) {
skb_pull(skb, delta);
memmove((char *)ip6_hdr + delta, ip6_hdr, size);
skb_reset_network_header(skb);
}
return 0;
}
static const struct netlbl_calipso_ops ops = {
.doi_add = calipso_doi_add,
.doi_free = calipso_doi_free,
.doi_remove = calipso_doi_remove,
.doi_getdef = calipso_doi_getdef,
.doi_putdef = calipso_doi_putdef,
.doi_walk = calipso_doi_walk,
.sock_getattr = calipso_sock_getattr,
.sock_setattr = calipso_sock_setattr,
.sock_delattr = calipso_sock_delattr,
.req_setattr = calipso_req_setattr,
.req_delattr = calipso_req_delattr,
.opt_getattr = calipso_opt_getattr,
.skbuff_optptr = calipso_skbuff_optptr,
.skbuff_setattr = calipso_skbuff_setattr,
.skbuff_delattr = calipso_skbuff_delattr,
.cache_invalidate = calipso_cache_invalidate,
.cache_add = calipso_cache_add
};
/**
* calipso_init - Initialize the CALIPSO module
*
* Description:
* Initialize the CALIPSO module and prepare it for use. Returns zero on
* success and negative values on failure.
*
*/
int __init calipso_init(void)
{
int ret_val;
ret_val = calipso_cache_init();
if (!ret_val)
netlbl_calipso_ops_register(&ops);
return ret_val;
}
void calipso_exit(void)
{
netlbl_calipso_ops_register(NULL);
calipso_cache_invalidate();
kfree(calipso_cache);
}
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