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Diffstat (limited to 'net/ipv6/calipso.c')
| -rw-r--r-- | net/ipv6/calipso.c | 1473 |
1 files changed, 1473 insertions, 0 deletions
diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c new file mode 100644 index 000000000000..c53b92c617c5 --- /dev/null +++ b/net/ipv6/calipso.c @@ -0,0 +1,1473 @@ +/* + * CALIPSO - Common Architecture Label IPv6 Security Option + * + * This is an implementation of the CALIPSO protocol as specified in + * RFC 5570. + * + * Authors: Paul Moore <paul.moore@hp.com> + * Huw Davies <huw@codeweavers.com> + * + */ + +/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 + * (c) Copyright Huw Davies <huw@codeweavers.com>, 2015 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + * + */ + +#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 <asm/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; + +/* 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; + atomic_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); + atomic_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 && atomic_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; + + atomic_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_secid: the LSM secid to use in the audit message + * + * 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; + } + if (!atomic_dec_and_test(&doi_def->refcount)) { + spin_unlock(&calipso_doi_list_lock); + ret_val = -EBUSY; + goto doi_remove_return; + } + list_del_rcu(&doi_def->list); + spin_unlock(&calipso_doi_list_lock); + + call_rcu(&doi_def->rcu, calipso_doi_free_rcu); + 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 (!atomic_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 (!atomic_dec_and_test(&doi_def->refcount)) + return; + spin_lock(&calipso_doi_list_lock); + list_del_rcu(&doi_def->list); + spin_unlock(&calipso_doi_list_lock); + + 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 (atomic_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) { + if (spot == -2) + return -EFAULT; + 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_kern(sk, old, IPV6_HOPOPTS, + hop, hop ? ipv6_optlen(hop) : 0); + 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) + 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; + } + + 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_kern(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, + new, new ? ipv6_optlen(new) : 0); + + 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 + * @reg: 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_kern(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, + new, new ? ipv6_optlen(new) : 0); + + 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; + 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; + + 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); + } + + 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); +} |