[net-next-2.6.git] / net / core / filter.c

/*
 * Linux Socket Filter - Kernel level socket filtering
 *
 * Author:
 *     Jay Schulist <jschlst@samba.org>
 *
 * Based on the design of:
 *     - The Berkeley Packet Filter
 *
 * 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.
 *
 * Andi Kleen - Fix a few bad bugs and races.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_packet.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/filter.h>

/* No hurry in this branch */
static void *__load_pointer(struct sk_buff *skb, int k)
{
	u8 *ptr = NULL;

	if (k >= SKF_NET_OFF)
		ptr = skb->nh.raw + k - SKF_NET_OFF;
	else if (k >= SKF_LL_OFF)
		ptr = skb->mac.raw + k - SKF_LL_OFF;

	if (ptr >= skb->head && ptr < skb->tail)
		return ptr;
	return NULL;
}

static inline void *load_pointer(struct sk_buff *skb, int k,
                                 unsigned int size, void *buffer)
{
	if (k >= 0)
		return skb_header_pointer(skb, k, size, buffer);
	else {
		if (k >= SKF_AD_OFF)
			return NULL;
		return __load_pointer(skb, k);
	}
}

/**
 *	sk_run_filter	- 	run a filter on a socket
 *	@skb: buffer to run the filter on
 *	@filter: filter to apply
 *	@flen: length of filter
 *
 * Decode and apply filter instructions to the skb->data.
 * Return length to keep, 0 for none. skb is the data we are
 * filtering, filter is the array of filter instructions, and
 * len is the number of filter blocks in the array.
 */
 
int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
{
	struct sock_filter *fentry;	/* We walk down these */
	void *ptr;
	u32 A = 0;	   		/* Accumulator */
	u32 X = 0;   			/* Index Register */
	u32 mem[BPF_MEMWORDS];		/* Scratch Memory Store */
	u32 tmp;
	int k;
	int pc;

	/*
	 * Process array of filter instructions.
	 */
	for (pc = 0; pc < flen; pc++) {
		fentry = &filter[pc];
			
		switch (fentry->code) {
		case BPF_ALU|BPF_ADD|BPF_X:
			A += X;
			continue;
		case BPF_ALU|BPF_ADD|BPF_K:
			A += fentry->k;
			continue;
		case BPF_ALU|BPF_SUB|BPF_X:
			A -= X;
			continue;
		case BPF_ALU|BPF_SUB|BPF_K:
			A -= fentry->k;
			continue;
		case BPF_ALU|BPF_MUL|BPF_X:
			A *= X;
			continue;
		case BPF_ALU|BPF_MUL|BPF_K:
			A *= fentry->k;
			continue;
		case BPF_ALU|BPF_DIV|BPF_X:
			if (X == 0)
				return 0;
			A /= X;
			continue;
		case BPF_ALU|BPF_DIV|BPF_K:
			if (fentry->k == 0)
				return 0;
			A /= fentry->k;
			continue;
		case BPF_ALU|BPF_AND|BPF_X:
			A &= X;
			continue;
		case BPF_ALU|BPF_AND|BPF_K:
			A &= fentry->k;
			continue;
		case BPF_ALU|BPF_OR|BPF_X:
			A |= X;
			continue;
		case BPF_ALU|BPF_OR|BPF_K:
			A |= fentry->k;
			continue;
		case BPF_ALU|BPF_LSH|BPF_X:
			A <<= X;
			continue;
		case BPF_ALU|BPF_LSH|BPF_K:
			A <<= fentry->k;
			continue;
		case BPF_ALU|BPF_RSH|BPF_X:
			A >>= X;
			continue;
		case BPF_ALU|BPF_RSH|BPF_K:
			A >>= fentry->k;
			continue;
		case BPF_ALU|BPF_NEG:
			A = -A;
			continue;
		case BPF_JMP|BPF_JA:
			pc += fentry->k;
			continue;
		case BPF_JMP|BPF_JGT|BPF_K:
			pc += (A > fentry->k) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JGE|BPF_K:
			pc += (A >= fentry->k) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JEQ|BPF_K:
			pc += (A == fentry->k) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JSET|BPF_K:
			pc += (A & fentry->k) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JGT|BPF_X:
			pc += (A > X) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JGE|BPF_X:
			pc += (A >= X) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JEQ|BPF_X:
			pc += (A == X) ? fentry->jt : fentry->jf;
			continue;
		case BPF_JMP|BPF_JSET|BPF_X:
			pc += (A & X) ? fentry->jt : fentry->jf;
			continue;
		case BPF_LD|BPF_W|BPF_ABS:
			k = fentry->k;
 load_w:
			ptr = load_pointer(skb, k, 4, &tmp);
			if (ptr != NULL) {
				A = ntohl(*(u32 *)ptr);
				continue;
			}
			return 0;
		case BPF_LD|BPF_H|BPF_ABS:
			k = fentry->k;
 load_h:
			ptr = load_pointer(skb, k, 2, &tmp);
			if (ptr != NULL) {
				A = ntohs(*(u16 *)ptr);
				continue;
			}
			return 0;
		case BPF_LD|BPF_B|BPF_ABS:
			k = fentry->k;
load_b:
			ptr = load_pointer(skb, k, 1, &tmp);
			if (ptr != NULL) {
				A = *(u8 *)ptr;
				continue;
			}
			return 0;
		case BPF_LD|BPF_W|BPF_LEN:
			A = skb->len;
			continue;
		case BPF_LDX|BPF_W|BPF_LEN:
			X = skb->len;
			continue;
		case BPF_LD|BPF_W|BPF_IND:
			k = X + fentry->k;
			goto load_w;
		case BPF_LD|BPF_H|BPF_IND:
			k = X + fentry->k;
			goto load_h;
		case BPF_LD|BPF_B|BPF_IND:
			k = X + fentry->k;
			goto load_b;
		case BPF_LDX|BPF_B|BPF_MSH:
			ptr = load_pointer(skb, fentry->k, 1, &tmp);
			if (ptr != NULL) {
				X = (*(u8 *)ptr & 0xf) << 2;
				continue;
			}
			return 0;
		case BPF_LD|BPF_IMM:
			A = fentry->k;
			continue;
		case BPF_LDX|BPF_IMM:
			X = fentry->k;
			continue;
		case BPF_LD|BPF_MEM:
			A = mem[fentry->k];
			continue;
		case BPF_LDX|BPF_MEM:
			X = mem[fentry->k];
			continue;
		case BPF_MISC|BPF_TAX:
			X = A;
			continue;
		case BPF_MISC|BPF_TXA:
			A = X;
			continue;
		case BPF_RET|BPF_K:
			return ((unsigned int)fentry->k);
		case BPF_RET|BPF_A:
			return ((unsigned int)A);
		case BPF_ST:
			mem[fentry->k] = A;
			continue;
		case BPF_STX:
			mem[fentry->k] = X;
			continue;
		default:
			/* Invalid instruction counts as RET */
			return 0;
		}

		/*
		 * Handle ancillary data, which are impossible
		 * (or very difficult) to get parsing packet contents.
		 */
		switch (k-SKF_AD_OFF) {
		case SKF_AD_PROTOCOL:
			A = htons(skb->protocol);
			continue;
		case SKF_AD_PKTTYPE:
			A = skb->pkt_type;
			continue;
		case SKF_AD_IFINDEX:
			A = skb->dev->ifindex;
			continue;
		default:
			return 0;
		}
	}

	return 0;
}

/**
 *	sk_chk_filter - verify socket filter code
 *	@filter: filter to verify
 *	@flen: length of filter
 *
 * Check the user's filter code. If we let some ugly
 * filter code slip through kaboom! The filter must contain
 * no references or jumps that are out of range, no illegal instructions
 * and no backward jumps. It must end with a RET instruction
 *
 * Returns 0 if the rule set is legal or a negative errno code if not.
 */
int sk_chk_filter(struct sock_filter *filter, int flen)
{
	struct sock_filter *ftest;
	int pc;

	if (((unsigned int)flen >= (~0U / sizeof(struct sock_filter))) || flen == 0)
		return -EINVAL;

	/* check the filter code now */
	for (pc = 0; pc < flen; pc++) {
		/* all jumps are forward as they are not signed */
		ftest = &filter[pc];
		if (BPF_CLASS(ftest->code) == BPF_JMP) {
			/* but they mustn't jump off the end */
			if (BPF_OP(ftest->code) == BPF_JA) {
				/*
				 * Note, the large ftest->k might cause loops.
				 * Compare this with conditional jumps below,
				 * where offsets are limited. --ANK (981016)
				 */
				if (ftest->k >= (unsigned)(flen-pc-1))
					return -EINVAL;
			} else {
				/* for conditionals both must be safe */
 				if (pc + ftest->jt +1 >= flen ||
				    pc + ftest->jf +1 >= flen)
					return -EINVAL;
			}
		}

		/* check that memory operations use valid addresses. */
		if (ftest->k >= BPF_MEMWORDS) {
			/* but it might not be a memory operation... */
			switch (ftest->code) {
			case BPF_ST:	
			case BPF_STX:	
			case BPF_LD|BPF_MEM:	
			case BPF_LDX|BPF_MEM:	
				return -EINVAL;
			}
		}
	}

	/*
	 * The program must end with a return. We don't care where they
	 * jumped within the script (its always forwards) but in the end
	 * they _will_ hit this.
	 */
        return (BPF_CLASS(filter[flen - 1].code) == BPF_RET) ? 0 : -EINVAL;
}

/**
 *	sk_attach_filter - attach a socket filter
 *	@fprog: the filter program
 *	@sk: the socket to use
 *
 * Attach the user's filter code. We first run some sanity checks on
 * it to make sure it does not explode on us later. If an error
 * occurs or there is insufficient memory for the filter a negative
 * errno code is returned. On success the return is zero.
 */
int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
{
	struct sk_filter *fp; 
	unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
	int err;

	/* Make sure new filter is there and in the right amounts. */
        if (fprog->filter == NULL || fprog->len > BPF_MAXINSNS)
                return -EINVAL;

	fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
	if (!fp)
		return -ENOMEM;
	if (copy_from_user(fp->insns, fprog->filter, fsize)) {
		sock_kfree_s(sk, fp, fsize+sizeof(*fp)); 
		return -EFAULT;
	}

	atomic_set(&fp->refcnt, 1);
	fp->len = fprog->len;

	err = sk_chk_filter(fp->insns, fp->len);
	if (!err) {
		struct sk_filter *old_fp;

		spin_lock_bh(&sk->sk_lock.slock);
		old_fp = sk->sk_filter;
		sk->sk_filter = fp;
		spin_unlock_bh(&sk->sk_lock.slock);
		fp = old_fp;
	}

	if (fp)
		sk_filter_release(sk, fp);
	return err;
}

EXPORT_SYMBOL(sk_chk_filter);
EXPORT_SYMBOL(sk_run_filter);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Linux Socket Filter - Kernel level socket filtering
	3	*
	4	* Author:
	5	* Jay Schulist <jschlst@samba.org>
	6	*
	7	* Based on the design of:
	8	* - The Berkeley Packet Filter
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License
	12	* as published by the Free Software Foundation; either version
	13	* 2 of the License, or (at your option) any later version.
	14	*
	15	* Andi Kleen - Fix a few bad bugs and races.
	16	*/
	17
	18	#include <linux/module.h>
	19	#include <linux/types.h>
	20	#include <linux/sched.h>
	21	#include <linux/mm.h>
	22	#include <linux/fcntl.h>
	23	#include <linux/socket.h>
	24	#include <linux/in.h>
	25	#include <linux/inet.h>
	26	#include <linux/netdevice.h>
	27	#include <linux/if_packet.h>
	28	#include <net/ip.h>
	29	#include <net/protocol.h>
	30	#include <linux/skbuff.h>
	31	#include <net/sock.h>
	32	#include <linux/errno.h>
	33	#include <linux/timer.h>
	34	#include <asm/system.h>
	35	#include <asm/uaccess.h>
	36	#include <linux/filter.h>
	37
	38	/* No hurry in this branch */
0b05b2a4	39	static void __load_pointer(struct sk_buff skb, int k)
1da177e4 LT	40	{
	41	u8 *ptr = NULL;
	42
	43	if (k >= SKF_NET_OFF)
	44	ptr = skb->nh.raw + k - SKF_NET_OFF;
	45	else if (k >= SKF_LL_OFF)
	46	ptr = skb->mac.raw + k - SKF_LL_OFF;
	47
	48	if (ptr >= skb->head && ptr < skb->tail)
	49	return ptr;
	50	return NULL;
	51	}
	52
0b05b2a4 PM	53	static inline void load_pointer(struct sk_buff skb, int k,
	54	unsigned int size, void *buffer)
	55	{
	56	if (k >= 0)
	57	return skb_header_pointer(skb, k, size, buffer);
	58	else {
	59	if (k >= SKF_AD_OFF)
	60	return NULL;
	61	return __load_pointer(skb, k);
	62	}
	63	}
	64
1da177e4 LT	65	/**
	66	* sk_run_filter - run a filter on a socket
	67	* @skb: buffer to run the filter on
	68	* @filter: filter to apply
	69	* @flen: length of filter
	70	*
	71	* Decode and apply filter instructions to the skb->data.
	72	* Return length to keep, 0 for none. skb is the data we are
	73	* filtering, filter is the array of filter instructions, and
	74	* len is the number of filter blocks in the array.
	75	*/
	76
	77	int sk_run_filter(struct sk_buff skb, struct sock_filter filter, int flen)
	78	{
1da177e4	79	struct sock_filter fentry; / We walk down these */
0b05b2a4	80	void *ptr;
1da177e4 LT	81	u32 A = 0; /* Accumulator */
	82	u32 X = 0; /* Index Register */
	83	u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */
0b05b2a4	84	u32 tmp;
1da177e4 LT	85	int k;
	86	int pc;
	87
	88	/*
	89	* Process array of filter instructions.
	90	*/
	91	for (pc = 0; pc < flen; pc++) {
	92	fentry = &filter[pc];
	93
	94	switch (fentry->code) {
	95	case BPF_ALU\|BPF_ADD\|BPF_X:
	96	A += X;
	97	continue;
	98	case BPF_ALU\|BPF_ADD\|BPF_K:
	99	A += fentry->k;
	100	continue;
	101	case BPF_ALU\|BPF_SUB\|BPF_X:
	102	A -= X;
	103	continue;
	104	case BPF_ALU\|BPF_SUB\|BPF_K:
	105	A -= fentry->k;
	106	continue;
	107	case BPF_ALU\|BPF_MUL\|BPF_X:
	108	A *= X;
	109	continue;
	110	case BPF_ALU\|BPF_MUL\|BPF_K:
	111	A *= fentry->k;
	112	continue;
	113	case BPF_ALU\|BPF_DIV\|BPF_X:
	114	if (X == 0)
	115	return 0;
	116	A /= X;
	117	continue;
	118	case BPF_ALU\|BPF_DIV\|BPF_K:
	119	if (fentry->k == 0)
	120	return 0;
	121	A /= fentry->k;
	122	continue;
	123	case BPF_ALU\|BPF_AND\|BPF_X:
	124	A &= X;
	125	continue;
	126	case BPF_ALU\|BPF_AND\|BPF_K:
	127	A &= fentry->k;
	128	continue;
	129	case BPF_ALU\|BPF_OR\|BPF_X:
	130	A \|= X;
	131	continue;
	132	case BPF_ALU\|BPF_OR\|BPF_K:
	133	A \|= fentry->k;
	134	continue;
	135	case BPF_ALU\|BPF_LSH\|BPF_X:
	136	A <<= X;
	137	continue;
	138	case BPF_ALU\|BPF_LSH\|BPF_K:
	139	A <<= fentry->k;
	140	continue;
	141	case BPF_ALU\|BPF_RSH\|BPF_X:
	142	A >>= X;
	143	continue;
	144	case BPF_ALU\|BPF_RSH\|BPF_K:
	145	A >>= fentry->k;
	146	continue;
	147	case BPF_ALU\|BPF_NEG:
	148	A = -A;
149	continue;
150	case BPF_JMP\|BPF_JA:
151	pc += fentry->k;
152	continue;
153	case BPF_JMP\|BPF_JGT\|BPF_K:
154	pc += (A > fentry->k) ? fentry->jt : fentry->jf;
155	continue;
156	case BPF_JMP\|BPF_JGE\|BPF_K:
157	pc += (A >= fentry->k) ? fentry->jt : fentry->jf;
158	continue;
159	case BPF_JMP\|BPF_JEQ\|BPF_K:
160	pc += (A == fentry->k) ? fentry->jt : fentry->jf;
161	continue;
162	case BPF_JMP\|BPF_JSET\|BPF_K:
163	pc += (A & fentry->k) ? fentry->jt : fentry->jf;
164	continue;
165	case BPF_JMP\|BPF_JGT\|BPF_X:
166	pc += (A > X) ? fentry->jt : fentry->jf;
167	continue;
168	case BPF_JMP\|BPF_JGE\|BPF_X:
169	pc += (A >= X) ? fentry->jt : fentry->jf;
170	continue;
171	case BPF_JMP\|BPF_JEQ\|BPF_X:
172	pc += (A == X) ? fentry->jt : fentry->jf;
173	continue;
174	case BPF_JMP\|BPF_JSET\|BPF_X:
175	pc += (A & X) ? fentry->jt : fentry->jf;
176	continue;
177	case BPF_LD\|BPF_W\|BPF_ABS:
178	k = fentry->k;
179	load_w:
0b05b2a4 PM	180	ptr = load_pointer(skb, k, 4, &tmp);
	181	if (ptr != NULL) {
	182	A = ntohl((u32 )ptr);
	183	continue;
1da177e4 LT	184	}
	185	return 0;
	186	case BPF_LD\|BPF_H\|BPF_ABS:
	187	k = fentry->k;
	188	load_h:
0b05b2a4 PM	189	ptr = load_pointer(skb, k, 2, &tmp);
	190	if (ptr != NULL) {
	191	A = ntohs((u16 )ptr);
	192	continue;
1da177e4 LT	193	}
	194	return 0;
	195	case BPF_LD\|BPF_B\|BPF_ABS:
	196	k = fentry->k;
	197	load_b:
0b05b2a4 PM	198	ptr = load_pointer(skb, k, 1, &tmp);
	199	if (ptr != NULL) {
	200	A = (u8 )ptr;
	201	continue;
1da177e4 LT	202	}
	203	return 0;
	204	case BPF_LD\|BPF_W\|BPF_LEN:
3154e540	205	A = skb->len;
1da177e4 LT	206	continue;
1da177e4 LT	207	case BPF_LDX\|BPF_W\|BPF_LEN:
3154e540	208	X = skb->len;
1da177e4 LT	209	continue;
	210	case BPF_LD\|BPF_W\|BPF_IND:
	211	k = X + fentry->k;
	212	goto load_w;
	213	case BPF_LD\|BPF_H\|BPF_IND:
	214	k = X + fentry->k;
	215	goto load_h;
	216	case BPF_LD\|BPF_B\|BPF_IND:
	217	k = X + fentry->k;
	218	goto load_b;
	219	case BPF_LDX\|BPF_B\|BPF_MSH:
0b05b2a4 PM	220	ptr = load_pointer(skb, fentry->k, 1, &tmp);
	221	if (ptr != NULL) {
	222	X = ((u8 )ptr & 0xf) << 2;
	223	continue;
	224	}
	225	return 0;
1da177e4 LT	226	case BPF_LD\|BPF_IMM:
	227	A = fentry->k;
	228	continue;
	229	case BPF_LDX\|BPF_IMM:
	230	X = fentry->k;
	231	continue;
	232	case BPF_LD\|BPF_MEM:
	233	A = mem[fentry->k];
	234	continue;
	235	case BPF_LDX\|BPF_MEM:
	236	X = mem[fentry->k];
	237	continue;
	238	case BPF_MISC\|BPF_TAX:
	239	X = A;
	240	continue;
	241	case BPF_MISC\|BPF_TXA:
	242	A = X;
	243	continue;
	244	case BPF_RET\|BPF_K:
	245	return ((unsigned int)fentry->k);
	246	case BPF_RET\|BPF_A:
	247	return ((unsigned int)A);
	248	case BPF_ST:
	249	mem[fentry->k] = A;
	250	continue;
	251	case BPF_STX:
	252	mem[fentry->k] = X;
	253	continue;
	254	default:
	255	/* Invalid instruction counts as RET */
	256	return 0;
	257	}
	258
	259	/*
	260	* Handle ancillary data, which are impossible
	261	* (or very difficult) to get parsing packet contents.
	262	*/
	263	switch (k-SKF_AD_OFF) {
	264	case SKF_AD_PROTOCOL:
	265	A = htons(skb->protocol);
	266	continue;
	267	case SKF_AD_PKTTYPE:
	268	A = skb->pkt_type;
	269	continue;
	270	case SKF_AD_IFINDEX:
	271	A = skb->dev->ifindex;
	272	continue;
	273	default:
	274	return 0;
	275	}
	276	}
	277
	278	return 0;
	279	}
	280
	281	/**
	282	* sk_chk_filter - verify socket filter code
	283	* @filter: filter to verify
	284	* @flen: length of filter
	285	*
	286	* Check the user's filter code. If we let some ugly
	287	* filter code slip through kaboom! The filter must contain
	288	* no references or jumps that are out of range, no illegal instructions
	289	* and no backward jumps. It must end with a RET instruction
290	*
291	* Returns 0 if the rule set is legal or a negative errno code if not.
292	*/
293	int sk_chk_filter(struct sock_filter *filter, int flen)
294	{
295	struct sock_filter *ftest;
296	int pc;
297
298	if (((unsigned int)flen >= (~0U / sizeof(struct sock_filter))) \|\| flen == 0)
299	return -EINVAL;
300
301	/* check the filter code now */
302	for (pc = 0; pc < flen; pc++) {
303	/* all jumps are forward as they are not signed */
304	ftest = &filter[pc];
305	if (BPF_CLASS(ftest->code) == BPF_JMP) {
306	/* but they mustn't jump off the end */
307	if (BPF_OP(ftest->code) == BPF_JA) {
308	/*
309	* Note, the large ftest->k might cause loops.
310	* Compare this with conditional jumps below,
311	* where offsets are limited. --ANK (981016)
312	*/
313	if (ftest->k >= (unsigned)(flen-pc-1))
314	return -EINVAL;
315	} else {
316	/* for conditionals both must be safe */
317	if (pc + ftest->jt +1 >= flen \|\|
318	pc + ftest->jf +1 >= flen)
319	return -EINVAL;
320	}
321	}
322
323	/* check that memory operations use valid addresses. */
324	if (ftest->k >= BPF_MEMWORDS) {
325	/* but it might not be a memory operation... */
326	switch (ftest->code) {
327	case BPF_ST:
328	case BPF_STX:
329	case BPF_LD\|BPF_MEM:
330	case BPF_LDX\|BPF_MEM:
331	return -EINVAL;
332	}
333	}
334	}
335
336	/*
337	* The program must end with a return. We don't care where they
338	* jumped within the script (its always forwards) but in the end
339	* they _will_ hit this.
340	*/
341	return (BPF_CLASS(filter[flen - 1].code) == BPF_RET) ? 0 : -EINVAL;
342	}
343
344	/**
345	* sk_attach_filter - attach a socket filter
346	* @fprog: the filter program
347	* @sk: the socket to use
348	*
349	* Attach the user's filter code. We first run some sanity checks on
350	* it to make sure it does not explode on us later. If an error
351	* occurs or there is insufficient memory for the filter a negative
352	* errno code is returned. On success the return is zero.
353	*/
354	int sk_attach_filter(struct sock_fprog fprog, struct sock sk)
355	{
356	struct sk_filter *fp;
357	unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
358	int err;
359
360	/* Make sure new filter is there and in the right amounts. */
361	if (fprog->filter == NULL \|\| fprog->len > BPF_MAXINSNS)
362	return -EINVAL;
363
364	fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
365	if (!fp)
366	return -ENOMEM;
367	if (copy_from_user(fp->insns, fprog->filter, fsize)) {
368	sock_kfree_s(sk, fp, fsize+sizeof(*fp));
369	return -EFAULT;
370	}
371
372	atomic_set(&fp->refcnt, 1);
373	fp->len = fprog->len;
374
375	err = sk_chk_filter(fp->insns, fp->len);
376	if (!err) {
377	struct sk_filter *old_fp;
378
379	spin_lock_bh(&sk->sk_lock.slock);
380	old_fp = sk->sk_filter;
381	sk->sk_filter = fp;
382	spin_unlock_bh(&sk->sk_lock.slock);
383	fp = old_fp;
384	}
385
386	if (fp)
387	sk_filter_release(sk, fp);
388	return err;
389	}
390
391	EXPORT_SYMBOL(sk_chk_filter);
392	EXPORT_SYMBOL(sk_run_filter);