[deliverable/linux.git] / net / ipv4 / ah4.c

#include <linux/config.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/ah.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <asm/scatterlist.h>


/* Clear mutable options and find final destination to substitute
 * into IP header for icv calculation. Options are already checked
 * for validity, so paranoia is not required. */

static int ip_clear_mutable_options(struct iphdr *iph, u32 *daddr)
{
	unsigned char * optptr = (unsigned char*)(iph+1);
	int  l = iph->ihl*4 - sizeof(struct iphdr);
	int  optlen;

	while (l > 0) {
		switch (*optptr) {
		case IPOPT_END:
			return 0;
		case IPOPT_NOOP:
			l--;
			optptr++;
			continue;
		}
		optlen = optptr[1];
		if (optlen<2 || optlen>l)
			return -EINVAL;
		switch (*optptr) {
		case IPOPT_SEC:
		case 0x85:	/* Some "Extended Security" crap. */
		case 0x86:	/* Another "Commercial Security" crap. */
		case IPOPT_RA:
		case 0x80|21:	/* RFC1770 */
			break;
		case IPOPT_LSRR:
		case IPOPT_SSRR:
			if (optlen < 6)
				return -EINVAL;
			memcpy(daddr, optptr+optlen-4, 4);
			/* Fall through */
		default:
			memset(optptr+2, 0, optlen-2);
		}
		l -= optlen;
		optptr += optlen;
	}
	return 0;
}

static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;
	struct iphdr *iph, *top_iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	union {
		struct iphdr	iph;
		char 		buf[60];
	} tmp_iph;

	top_iph = skb->nh.iph;
	iph = &tmp_iph.iph;

	iph->tos = top_iph->tos;
	iph->ttl = top_iph->ttl;
	iph->frag_off = top_iph->frag_off;

	if (top_iph->ihl != 5) {
		iph->daddr = top_iph->daddr;
		memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
		err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
		if (err)
			goto error;
	}

	ah = (struct ip_auth_hdr *)((char *)top_iph+top_iph->ihl*4);
	ah->nexthdr = top_iph->protocol;

	top_iph->tos = 0;
	top_iph->tot_len = htons(skb->len);
	top_iph->frag_off = 0;
	top_iph->ttl = 0;
	top_iph->protocol = IPPROTO_AH;
	top_iph->check = 0;

	ahp = x->data;
	ah->hdrlen  = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 
				   ahp->icv_trunc_len) >> 2) - 2;

	ah->reserved = 0;
	ah->spi = x->id.spi;
	ah->seq_no = htonl(++x->replay.oseq);
	ahp->icv(ahp, skb, ah->auth_data);

	top_iph->tos = iph->tos;
	top_iph->ttl = iph->ttl;
	top_iph->frag_off = iph->frag_off;
	if (top_iph->ihl != 5) {
		top_iph->daddr = iph->daddr;
		memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
	}

	ip_send_check(top_iph);

	err = 0;

error:
	return err;
}

static int ah_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
	int ah_hlen;
	struct iphdr *iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	char work_buf[60];

	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
		goto out;

	ah = (struct ip_auth_hdr*)skb->data;
	ahp = x->data;
	ah_hlen = (ah->hdrlen + 2) << 2;
	
	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
	    ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len)) 
		goto out;

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	ah = (struct ip_auth_hdr*)skb->data;
	iph = skb->nh.iph;

	memcpy(work_buf, iph, iph->ihl*4);

	iph->ttl = 0;
	iph->tos = 0;
	iph->frag_off = 0;
	iph->check = 0;
	if (iph->ihl != 5) {
		u32 dummy;
		if (ip_clear_mutable_options(iph, &dummy))
			goto out;
	}
        {
		u8 auth_data[MAX_AH_AUTH_LEN];
		
		memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
		skb_push(skb, skb->data - skb->nh.raw);
		ahp->icv(ahp, skb, ah->auth_data);
		if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
			x->stats.integrity_failed++;
			goto out;
		}
	}
	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
	skb->nh.raw = skb_pull(skb, ah_hlen);
	memcpy(skb->nh.raw, work_buf, iph->ihl*4);
	skb->nh.iph->tot_len = htons(skb->len);
	skb_pull(skb, skb->nh.iph->ihl*4);
	skb->h.raw = skb->data;

	return 0;

out:
	return -EINVAL;
}

static void ah4_err(struct sk_buff *skb, u32 info)
{
	struct iphdr *iph = (struct iphdr*)skb->data;
	struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
	    skb->h.icmph->code != ICMP_FRAG_NEEDED)
		return;

	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
	if (!x)
		return;
	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
	       ntohl(ah->spi), ntohl(iph->daddr));
	xfrm_state_put(x);
}

static int ah_init_state(struct xfrm_state *x)
{
	struct ah_data *ahp = NULL;
	struct xfrm_algo_desc *aalg_desc;

	if (!x->aalg)
		goto error;

	/* null auth can use a zero length key */
	if (x->aalg->alg_key_len > 512)
		goto error;

	if (x->encap)
		goto error;

	ahp = kmalloc(sizeof(*ahp), GFP_KERNEL);
	if (ahp == NULL)
		return -ENOMEM;

	memset(ahp, 0, sizeof(*ahp));

	ahp->key = x->aalg->alg_key;
	ahp->key_len = (x->aalg->alg_key_len+7)/8;
	ahp->tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
	if (!ahp->tfm)
		goto error;
	ahp->icv = ah_hmac_digest;
	
	/*
	 * Lookup the algorithm description maintained by xfrm_algo,
	 * verify crypto transform properties, and store information
	 * we need for AH processing.  This lookup cannot fail here
	 * after a successful crypto_alloc_tfm().
	 */
	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	BUG_ON(!aalg_desc);

	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	    crypto_tfm_alg_digestsize(ahp->tfm)) {
		printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
		       x->aalg->alg_name, crypto_tfm_alg_digestsize(ahp->tfm),
		       aalg_desc->uinfo.auth.icv_fullbits/8);
		goto error;
	}
	
	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
	
	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
	
	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	if (!ahp->work_icv)
		goto error;
	
	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
	if (x->props.mode)
		x->props.header_len += sizeof(struct iphdr);
	x->data = ahp;

	return 0;

error:
	if (ahp) {
		kfree(ahp->work_icv);
		crypto_free_tfm(ahp->tfm);
		kfree(ahp);
	}
	return -EINVAL;
}

static void ah_destroy(struct xfrm_state *x)
{
	struct ah_data *ahp = x->data;

	if (!ahp)
		return;

	kfree(ahp->work_icv);
	ahp->work_icv = NULL;
	crypto_free_tfm(ahp->tfm);
	ahp->tfm = NULL;
	kfree(ahp);
}


static struct xfrm_type ah_type =
{
	.description	= "AH4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_AH,
	.init_state	= ah_init_state,
	.destructor	= ah_destroy,
	.input		= ah_input,
	.output		= ah_output
};

static struct net_protocol ah4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ah4_err,
	.no_policy	=	1,
};

static int __init ah4_init(void)
{
	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
		printk(KERN_INFO "ip ah init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
		printk(KERN_INFO "ip ah init: can't add protocol\n");
		xfrm_unregister_type(&ah_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ah4_fini(void)
{
	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
		printk(KERN_INFO "ip ah close: can't remove protocol\n");
	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
		printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
}

module_init(ah4_init);
module_exit(ah4_fini);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	#include <linux/config.h>
	2	#include <linux/module.h>
	3	#include <net/ip.h>
	4	#include <net/xfrm.h>
	5	#include <net/ah.h>
	6	#include <linux/crypto.h>
	7	#include <linux/pfkeyv2.h>
	8	#include <net/icmp.h>
14c85021	9	#include <net/protocol.h>
1da177e4 LT	10	#include <asm/scatterlist.h>
	11
	12
	13	/* Clear mutable options and find final destination to substitute
	14	* into IP header for icv calculation. Options are already checked
	15	* for validity, so paranoia is not required. */
	16
	17	static int ip_clear_mutable_options(struct iphdr iph, u32 daddr)
	18	{
	19	unsigned char * optptr = (unsigned char*)(iph+1);
	20	int l = iph->ihl*4 - sizeof(struct iphdr);
	21	int optlen;
	22
	23	while (l > 0) {
	24	switch (*optptr) {
	25	case IPOPT_END:
	26	return 0;
	27	case IPOPT_NOOP:
	28	l--;
	29	optptr++;
	30	continue;
	31	}
	32	optlen = optptr[1];
	33	if (optlen<2 \|\| optlen>l)
	34	return -EINVAL;
	35	switch (*optptr) {
	36	case IPOPT_SEC:
	37	case 0x85: /* Some "Extended Security" crap. */
	38	case 0x86: /* Another "Commercial Security" crap. */
	39	case IPOPT_RA:
	40	case 0x80\|21: /* RFC1770 */
	41	break;
	42	case IPOPT_LSRR:
	43	case IPOPT_SSRR:
	44	if (optlen < 6)
	45	return -EINVAL;
	46	memcpy(daddr, optptr+optlen-4, 4);
	47	/* Fall through */
	48	default:
	49	memset(optptr+2, 0, optlen-2);
	50	}
	51	l -= optlen;
	52	optptr += optlen;
	53	}
	54	return 0;
	55	}
	56
	57	static int ah_output(struct xfrm_state x, struct sk_buff skb)
	58	{
	59	int err;
	60	struct iphdr iph, top_iph;
	61	struct ip_auth_hdr *ah;
	62	struct ah_data *ahp;
	63	union {
	64	struct iphdr iph;
	65	char buf[60];
	66	} tmp_iph;
	67
	68	top_iph = skb->nh.iph;
	69	iph = &tmp_iph.iph;
	70
	71	iph->tos = top_iph->tos;
	72	iph->ttl = top_iph->ttl;
	73	iph->frag_off = top_iph->frag_off;
74
75	if (top_iph->ihl != 5) {
76	iph->daddr = top_iph->daddr;
77	memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
78	err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
79	if (err)
80	goto error;
81	}
82
83	ah = (struct ip_auth_hdr )((char )top_iph+top_iph->ihl*4);
84	ah->nexthdr = top_iph->protocol;
85
86	top_iph->tos = 0;
87	top_iph->tot_len = htons(skb->len);
88	top_iph->frag_off = 0;
89	top_iph->ttl = 0;
90	top_iph->protocol = IPPROTO_AH;
91	top_iph->check = 0;
92
93	ahp = x->data;
94	ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
95	ahp->icv_trunc_len) >> 2) - 2;
96
97	ah->reserved = 0;
98	ah->spi = x->id.spi;
99	ah->seq_no = htonl(++x->replay.oseq);
100	ahp->icv(ahp, skb, ah->auth_data);
101
102	top_iph->tos = iph->tos;
103	top_iph->ttl = iph->ttl;
104	top_iph->frag_off = iph->frag_off;
105	if (top_iph->ihl != 5) {
106	top_iph->daddr = iph->daddr;
107	memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
108	}
109
110	ip_send_check(top_iph);
111
112	err = 0;
113
114	error:
115	return err;
116	}
117
118	static int ah_input(struct xfrm_state x, struct xfrm_decap_state decap, struct sk_buff *skb)
119	{
120	int ah_hlen;
121	struct iphdr *iph;
122	struct ip_auth_hdr *ah;
123	struct ah_data *ahp;
124	char work_buf[60];
125
126	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
127	goto out;
128
129	ah = (struct ip_auth_hdr*)skb->data;
130	ahp = x->data;
131	ah_hlen = (ah->hdrlen + 2) << 2;
132
133	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
134	ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len))
135	goto out;
136
137	if (!pskb_may_pull(skb, ah_hlen))
138	goto out;
139
140	/* We are going to _remove_ AH header to keep sockets happy,
141	* so... Later this can change. */
142	if (skb_cloned(skb) &&
143	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
144	goto out;
145
146	skb->ip_summed = CHECKSUM_NONE;
147
148	ah = (struct ip_auth_hdr*)skb->data;
149	iph = skb->nh.iph;
150
151	memcpy(work_buf, iph, iph->ihl*4);
152
153	iph->ttl = 0;
154	iph->tos = 0;
155	iph->frag_off = 0;
156	iph->check = 0;
157	if (iph->ihl != 5) {
158	u32 dummy;
159	if (ip_clear_mutable_options(iph, &dummy))
160	goto out;
161	}
162	{
163	u8 auth_data[MAX_AH_AUTH_LEN];
164
165	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
166	skb_push(skb, skb->data - skb->nh.raw);
167	ahp->icv(ahp, skb, ah->auth_data);
168	if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
169	x->stats.integrity_failed++;
170	goto out;
171	}
172	}
173	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
174	skb->nh.raw = skb_pull(skb, ah_hlen);
175	memcpy(skb->nh.raw, work_buf, iph->ihl*4);
176	skb->nh.iph->tot_len = htons(skb->len);
177	skb_pull(skb, skb->nh.iph->ihl*4);
178	skb->h.raw = skb->data;
179
180	return 0;
181
182	out:
183	return -EINVAL;
184	}
185
186	static void ah4_err(struct sk_buff *skb, u32 info)
187	{
188	struct iphdr iph = (struct iphdr)skb->data;
189	struct ip_auth_hdr ah = (struct ip_auth_hdr)(skb->data+(iph->ihl<<2));
190	struct xfrm_state *x;
191
192	if (skb->h.icmph->type != ICMP_DEST_UNREACH \|\|
193	skb->h.icmph->code != ICMP_FRAG_NEEDED)
194	return;
195
196	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET);
197	if (!x)
198	return;
199	printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
200	ntohl(ah->spi), ntohl(iph->daddr));
201	xfrm_state_put(x);
202	}
203
72cb6962	204	static int ah_init_state(struct xfrm_state *x)
1da177e4 LT	205	{
	206	struct ah_data *ahp = NULL;
	207	struct xfrm_algo_desc *aalg_desc;
	208
	209	if (!x->aalg)
	210	goto error;
	211
	212	/* null auth can use a zero length key */
	213	if (x->aalg->alg_key_len > 512)
	214	goto error;
	215
	216	if (x->encap)
	217	goto error;
	218
	219	ahp = kmalloc(sizeof(*ahp), GFP_KERNEL);
	220	if (ahp == NULL)
	221	return -ENOMEM;
	222
	223	memset(ahp, 0, sizeof(*ahp));
	224
	225	ahp->key = x->aalg->alg_key;
	226	ahp->key_len = (x->aalg->alg_key_len+7)/8;
	227	ahp->tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
	228	if (!ahp->tfm)
	229	goto error;
	230	ahp->icv = ah_hmac_digest;
	231
	232	/*
	233	* Lookup the algorithm description maintained by xfrm_algo,
	234	* verify crypto transform properties, and store information
	235	* we need for AH processing. This lookup cannot fail here
	236	* after a successful crypto_alloc_tfm().
	237	*/
	238	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
	239	BUG_ON(!aalg_desc);
	240
	241	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
	242	crypto_tfm_alg_digestsize(ahp->tfm)) {
	243	printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
	244	x->aalg->alg_name, crypto_tfm_alg_digestsize(ahp->tfm),
	245	aalg_desc->uinfo.auth.icv_fullbits/8);
	246	goto error;
	247	}
	248
	249	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
	250	ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
	251
	252	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
	253
	254	ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
	255	if (!ahp->work_icv)
	256	goto error;
	257
	258	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len);
	259	if (x->props.mode)
	260	x->props.header_len += sizeof(struct iphdr);
	261	x->data = ahp;
	262
	263	return 0;
	264
	265	error:
	266	if (ahp) {
573dbd95 JJ	267	kfree(ahp->work_icv);
573dbd95 JJ	268	crypto_free_tfm(ahp->tfm);
1da177e4 LT	269	kfree(ahp);
	270	}
	271	return -EINVAL;
	272	}
	273
	274	static void ah_destroy(struct xfrm_state *x)
	275	{
	276	struct ah_data *ahp = x->data;
	277
	278	if (!ahp)
	279	return;
	280
573dbd95 JJ	281	kfree(ahp->work_icv);
	282	ahp->work_icv = NULL;
	283	crypto_free_tfm(ahp->tfm);
	284	ahp->tfm = NULL;
1da177e4 LT	285	kfree(ahp);
	286	}
	287
	288
	289	static struct xfrm_type ah_type =
	290	{
	291	.description = "AH4",
	292	.owner = THIS_MODULE,
	293	.proto = IPPROTO_AH,
	294	.init_state = ah_init_state,
	295	.destructor = ah_destroy,
	296	.input = ah_input,
	297	.output = ah_output
	298	};
	299
	300	static struct net_protocol ah4_protocol = {
	301	.handler = xfrm4_rcv,
	302	.err_handler = ah4_err,
	303	.no_policy = 1,
	304	};
	305
	306	static int __init ah4_init(void)
	307	{
	308	if (xfrm_register_type(&ah_type, AF_INET) < 0) {
	309	printk(KERN_INFO "ip ah init: can't add xfrm type\n");
	310	return -EAGAIN;
	311	}
	312	if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
	313	printk(KERN_INFO "ip ah init: can't add protocol\n");
	314	xfrm_unregister_type(&ah_type, AF_INET);
	315	return -EAGAIN;
	316	}
	317	return 0;
	318	}
	319
	320	static void __exit ah4_fini(void)
	321	{
	322	if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
	323	printk(KERN_INFO "ip ah close: can't remove protocol\n");
	324	if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
	325	printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
	326	}
	327
	328	module_init(ah4_init);
	329	module_exit(ah4_fini);
	330	MODULE_LICENSE("GPL");