*/
/*
- * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
*
* 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
}
/**
- * cipso_v4_sock_setattr - Add a CIPSO option to a socket
- * @sk: the socket
+ * cipso_v4_genopt - Generate a CIPSO option
+ * @buf: the option buffer
+ * @buf_len: the size of opt_buf
* @doi_def: the CIPSO DOI to use
- * @secattr: the specific security attributes of the socket
+ * @secattr: the security attributes
*
* Description:
- * Set the CIPSO 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.
+ * Generate a CIPSO option using the DOI definition and security attributes
+ * passed to the function. Returns the length of the option on success and
+ * negative values on failure.
*
*/
-int cipso_v4_sock_setattr(struct sock *sk,
- const struct cipso_v4_doi *doi_def,
- const struct netlbl_lsm_secattr *secattr)
+static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
+ const struct cipso_v4_doi *doi_def,
+ const struct netlbl_lsm_secattr *secattr)
{
- int ret_val = -EPERM;
+ int ret_val;
u32 iter;
- unsigned char *buf;
- u32 buf_len = 0;
- u32 opt_len;
- struct ip_options *opt = NULL;
- struct inet_sock *sk_inet;
- struct inet_connection_sock *sk_conn;
-
- /* In the case of sock_create_lite(), the sock->sk field is not
- * defined yet but it is not a problem as the only users of these
- * "lite" PF_INET sockets are functions which do an accept() call
- * afterwards so we will label the socket as part of the accept(). */
- if (sk == NULL)
- return 0;
- /* We allocate the maximum CIPSO option size here so we are probably
- * being a little wasteful, but it makes our life _much_ easier later
- * on and after all we are only talking about 40 bytes. */
- buf_len = CIPSO_V4_OPT_LEN_MAX;
- buf = kmalloc(buf_len, GFP_ATOMIC);
- if (buf == NULL) {
- ret_val = -ENOMEM;
- goto socket_setattr_failure;
- }
+ if (buf_len <= CIPSO_V4_HDR_LEN)
+ return -ENOSPC;
/* XXX - This code assumes only one tag per CIPSO option which isn't
* really a good assumption to make but since we only support the MAC
buf_len - CIPSO_V4_HDR_LEN);
break;
default:
- ret_val = -EPERM;
- goto socket_setattr_failure;
+ return -EPERM;
}
iter++;
iter < CIPSO_V4_TAG_MAXCNT &&
doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
if (ret_val < 0)
- goto socket_setattr_failure;
+ return ret_val;
cipso_v4_gentag_hdr(doi_def, buf, ret_val);
- buf_len = CIPSO_V4_HDR_LEN + ret_val;
+ return CIPSO_V4_HDR_LEN + ret_val;
+}
+
+/**
+ * cipso_v4_sock_setattr - Add a CIPSO option to a socket
+ * @sk: the socket
+ * @doi_def: the CIPSO DOI to use
+ * @secattr: the specific security attributes of the socket
+ *
+ * Description:
+ * Set the CIPSO 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.
+ *
+ */
+int cipso_v4_sock_setattr(struct sock *sk,
+ const struct cipso_v4_doi *doi_def,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -EPERM;
+ unsigned char *buf = NULL;
+ u32 buf_len;
+ u32 opt_len;
+ struct ip_options *opt = NULL;
+ struct inet_sock *sk_inet;
+ struct inet_connection_sock *sk_conn;
+
+ /* In the case of sock_create_lite(), the sock->sk field is not
+ * defined yet but it is not a problem as the only users of these
+ * "lite" PF_INET sockets are functions which do an accept() call
+ * afterwards so we will label the socket as part of the accept(). */
+ if (sk == NULL)
+ return 0;
+
+ /* We allocate the maximum CIPSO option size here so we are probably
+ * being a little wasteful, but it makes our life _much_ easier later
+ * on and after all we are only talking about 40 bytes. */
+ buf_len = CIPSO_V4_OPT_LEN_MAX;
+ buf = kmalloc(buf_len, GFP_ATOMIC);
+ if (buf == NULL) {
+ ret_val = -ENOMEM;
+ goto socket_setattr_failure;
+ }
+
+ ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
+ if (ret_val < 0)
+ goto socket_setattr_failure;
+ buf_len = ret_val;
/* We can't use ip_options_get() directly because it makes a call to
* ip_options_get_alloc() which allocates memory with GFP_KERNEL and
secattr);
}
+/**
+ * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
+ * @skb: the packet
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Set the CIPSO option on the given packet based on the security attributes.
+ * Returns a pointer to the IP header on success and NULL on failure.
+ *
+ */
+int cipso_v4_skbuff_setattr(struct sk_buff *skb,
+ const struct cipso_v4_doi *doi_def,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val;
+ struct iphdr *iph;
+ struct ip_options *opt = &IPCB(skb)->opt;
+ unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
+ u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
+ u32 opt_len;
+ int len_delta;
+
+ buf_len = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
+ if (buf_len < 0)
+ return buf_len;
+ opt_len = (buf_len + 3) & ~3;
+
+ /* we overwrite any existing options to ensure that we have enough
+ * room for the CIPSO option, the reason is that we _need_ to guarantee
+ * that the security label is applied to the packet - we do the same
+ * thing when using the socket options and it hasn't caused a problem,
+ * if we need to we can always revisit this choice later */
+
+ len_delta = opt_len - opt->optlen;
+ /* if we don't ensure enough headroom we could panic on the skb_push()
+ * call below so make sure we have enough, we are also "mangling" the
+ * packet so we should probably do a copy-on-write call anyway */
+ ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
+ if (ret_val < 0)
+ return ret_val;
+
+ if (len_delta > 0) {
+ /* we assume that the header + opt->optlen have already been
+ * "pushed" in ip_options_build() or similar */
+ iph = ip_hdr(skb);
+ skb_push(skb, len_delta);
+ memmove((char *)iph - len_delta, iph, iph->ihl << 2);
+ skb_reset_network_header(skb);
+ iph = ip_hdr(skb);
+ } else if (len_delta < 0) {
+ iph = ip_hdr(skb);
+ memset(iph + 1, IPOPT_NOP, opt->optlen);
+ } else
+ iph = ip_hdr(skb);
+
+ if (opt->optlen > 0)
+ memset(opt, 0, sizeof(*opt));
+ opt->optlen = opt_len;
+ opt->cipso = sizeof(struct iphdr);
+ opt->is_changed = 1;
+
+ /* we have to do the following because we are being called from a
+ * netfilter hook which means the packet already has had the header
+ * fields populated and the checksum calculated - yes this means we
+ * are doing more work than needed but we do it to keep the core
+ * stack clean and tidy */
+ memcpy(iph + 1, buf, buf_len);
+ if (opt_len > buf_len)
+ memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
+ if (len_delta != 0) {
+ iph->ihl = 5 + (opt_len >> 2);
+ iph->tot_len = htons(skb->len);
+ }
+ ip_send_check(iph);
+
+ return 0;
+}
+
+/**
+ * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
+ * @skb: the packet
+ *
+ * Description:
+ * Removes any and all CIPSO options from the given packet. Returns zero on
+ * success, negative values on failure.
+ *
+ */
+int cipso_v4_skbuff_delattr(struct sk_buff *skb)
+{
+ int ret_val;
+ struct iphdr *iph;
+ struct ip_options *opt = &IPCB(skb)->opt;
+ unsigned char *cipso_ptr;
+
+ if (opt->cipso == 0)
+ 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;
+
+ /* the easiest thing to do is just replace the cipso option with noop
+ * options since we don't change the size of the packet, although we
+ * still need to recalculate the checksum */
+
+ iph = ip_hdr(skb);
+ cipso_ptr = (unsigned char *)iph + opt->cipso;
+ memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
+ opt->cipso = 0;
+ opt->is_changed = 1;
+
+ ip_send_check(iph);
+
+ return 0;
+}
+
/**
* cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option
* @skb: the packet
projects / linux-2.6-omap-h63xx.git / blobdiff