[NETFILTER]: Linearize iptables targets.

Adjusts the IPTables targets to handle non-linear packets.
ipt_ULOG untested.

net/ipv4/netfilter/ipt_DSCP.c

@@ -23,37 +23,31 @@ MODULE_LICENSE("GPL");
 
 static unsigned int
 target(struct sk_buff **pskb,
-       unsigned int hooknum,
        const struct net_device *in,
        const struct net_device *out,
+       unsigned int hooknum,
        const void *targinfo,
        void *userinfo)
 {
-	struct iphdr *iph = (*pskb)->nh.iph;
 	const struct ipt_DSCP_info *dinfo = targinfo;
 	u_int8_t sh_dscp = ((dinfo->dscp << IPT_DSCP_SHIFT) & IPT_DSCP_MASK);
 
 
-	if ((iph->tos & IPT_DSCP_MASK) != sh_dscp) {
+	if (((*pskb)->nh.iph->tos & IPT_DSCP_MASK) != sh_dscp) {
 		u_int16_t diffs[2];
 
-		/* raw socket (tcpdump) may have clone of incoming
-		 * skb: don't disturb it --RR */
-		if (skb_cloned(*pskb) && !(*pskb)->sk) {
-			struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
-			if (!nskb)
+		if (!skb_ip_make_writable(pskb, sizeof(struct iphdr)))
 			return NF_DROP;
-			kfree_skb(*pskb);
-			*pskb = nskb;
-			iph = (*pskb)->nh.iph;
-		}
 
-		diffs[0] = htons(iph->tos) ^ 0xFFFF;
-		iph->tos = (iph->tos & ~IPT_DSCP_MASK) | sh_dscp;
-		diffs[1] = htons(iph->tos);
-		iph->check = csum_fold(csum_partial((char *)diffs,
+		diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
+		(*pskb)->nh.iph->tos = ((*pskb)->nh.iph->tos & ~IPT_DSCP_MASK)
+			| sh_dscp;
+		diffs[1] = htons((*pskb)->nh.iph->tos);
+		(*pskb)->nh.iph->check
+			= csum_fold(csum_partial((char *)diffs,
 						 sizeof(diffs),
-		                                    iph->check^0xFFFF));
+						 (*pskb)->nh.iph->check
+						 ^ 0xFFFF));
 		(*pskb)->nfcache |= NFC_ALTERED;
 	}
 	return IPT_CONTINUE;

net/ipv4/netfilter/ipt_ECN.c

@@ -19,105 +19,85 @@
 MODULE_LICENSE("GPL");
 
 /* set ECT codepoint from IP header.
- * 	return 0 in case there was no ECT codepoint
- * 	return 1 in case ECT codepoint has been overwritten
- * 	return < 0 in case there was error */
+ * 	return 0 if there was an error. */
 static inline int
-set_ect_ip(struct sk_buff **pskb, struct iphdr *iph,
-	   const struct ipt_ECN_info *einfo)
+set_ect_ip(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)
 {
-	if ((iph->tos & IPT_ECN_IP_MASK)
+	if (((*pskb)->nh.iph->tos & IPT_ECN_IP_MASK)
 	    != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
 		u_int16_t diffs[2];
 
-		/* raw socket (tcpdump) may have clone of incoming
-		 * skb: don't disturb it --RR */
-		if (skb_cloned(*pskb) && !(*pskb)->sk) {
-			struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
-			if (!nskb)
-				return NF_DROP;
-			kfree_skb(*pskb);
-			*pskb = nskb;
-			iph = (*pskb)->nh.iph;
-		}
+		if (!skb_ip_make_writable(pskb, sizeof(struct iphdr)))
+			return 0;
 
-		diffs[0] = htons(iph->tos) ^ 0xFFFF;
-		iph->tos = iph->tos & ~IPT_ECN_IP_MASK;
-		iph->tos = iph->tos | (einfo->ip_ect & IPT_ECN_IP_MASK);
-		diffs[1] = htons(iph->tos);
-		iph->check = csum_fold(csum_partial((char *)diffs,
+		diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
+		(*pskb)->nh.iph->tos &= ~IPT_ECN_IP_MASK;
+		(*pskb)->nh.iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
+		diffs[1] = htons((*pskb)->nh.iph->tos);
+		(*pskb)->nh.iph->check
+			= csum_fold(csum_partial((char *)diffs,
 						 sizeof(diffs),
-		                                    iph->check^0xFFFF));
+						 (*pskb)->nh.iph->check
+						 ^0xFFFF));
 		(*pskb)->nfcache |= NFC_ALTERED;
-
-		return 1;
 	} 
-	return 0;
+	return 1;
 }
 
+/* Return 0 if there was an error. */
 static inline int
-set_ect_tcp(struct sk_buff **pskb, struct iphdr *iph,
-	    const struct ipt_ECN_info *einfo)
+set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)
 {
-
-	struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
-	u_int16_t *tcpflags = (u_int16_t *)tcph + 6;
+	struct tcphdr tcph;
 	u_int16_t diffs[2];
 
-	/* raw socket (tcpdump) may have clone of incoming
-	 * skb: don't disturb it --RR */
-	if (skb_cloned(*pskb) && !(*pskb)->sk) {
-		struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
-		if (!nskb)
-			return NF_DROP;
-		kfree_skb(*pskb);
-		*pskb = nskb;
-		iph = (*pskb)->nh.iph;
-	}
-
-	diffs[0] = *tcpflags;
+	/* Not enought header? */
+	if (skb_copy_bits(*pskb, (*pskb)->nh.iph->ihl*4, &tcph, sizeof(tcph))
+	    < 0)
+		return 0;
 
-	if (einfo->operation & IPT_ECN_OP_SET_ECE
-	    && tcph->ece != einfo->proto.tcp.ece) {
-		tcph->ece = einfo->proto.tcp.ece;
-	}
+	diffs[0] = ((u_int16_t *)&tcph)[6];
+	if (einfo->operation & IPT_ECN_OP_SET_ECE)
+		tcph.ece = einfo->proto.tcp.ece;
 
-	if (einfo->operation & IPT_ECN_OP_SET_CWR
-	    && tcph->cwr != einfo->proto.tcp.cwr) {
-		tcph->cwr = einfo->proto.tcp.cwr;
-	}
+	if (einfo->operation & IPT_ECN_OP_SET_CWR)
+		tcph.cwr = einfo->proto.tcp.cwr;
+	diffs[1] = ((u_int16_t *)&tcph)[6];
 
-	if (diffs[0] != *tcpflags) {
+	/* Only mangle if it's changed. */
+	if (diffs[0] != diffs[1]) {
 		diffs[0] = diffs[0] ^ 0xFFFF;
-		diffs[1] = *tcpflags;
-		tcph->check = csum_fold(csum_partial((char *)diffs,
+		if (!skb_ip_make_writable(pskb,
+					  (*pskb)->nh.iph->ihl*4+sizeof(tcph)))
+			return 0;
+		tcph.check = csum_fold(csum_partial((char *)diffs,
 		                                    sizeof(diffs),
-		                                    tcph->check^0xFFFF));
+		                                    tcph.check^0xFFFF));
+		memcpy((*pskb)->data + (*pskb)->nh.iph->ihl*4,
+		       &tcph, sizeof(tcph));
 		(*pskb)->nfcache |= NFC_ALTERED;
-
-		return 1;
 	}
-
-	return 0;
+	return 1;
 }
 
 static unsigned int
 target(struct sk_buff **pskb,
-       unsigned int hooknum,
        const struct net_device *in,
        const struct net_device *out,
+       unsigned int hooknum,
        const void *targinfo,
        void *userinfo)
 {
-	struct iphdr *iph = (*pskb)->nh.iph;
 	const struct ipt_ECN_info *einfo = targinfo;
 
 	if (einfo->operation & IPT_ECN_OP_SET_IP)
-		set_ect_ip(pskb, iph, einfo);
+		if (!set_ect_ip(pskb, einfo))
+			return NF_DROP;
 
 	if (einfo->operation & (IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR)
-	    && iph->protocol == IPPROTO_TCP)
-		set_ect_tcp(pskb, iph, einfo);
+	    && (*pskb)->nh.iph->protocol == IPPROTO_TCP)
+		if (!set_ect_tcp(pskb, einfo))
+			return NF_DROP;
 
 	return IPT_CONTINUE;
 }

net/ipv4/netfilter/ipt_LOG.c

@@ -29,127 +29,151 @@ static spinlock_t log_lock = SPIN_LOCK_UNLOCKED;
 
 /* One level of recursion won't kill us */
 static void dump_packet(const struct ipt_log_info *info,
-			struct iphdr *iph, unsigned int len, int recurse)
+			const struct sk_buff *skb,
+			unsigned int iphoff)
 {
-	void *protoh = (u_int32_t *)iph + iph->ihl;
-	unsigned int datalen = len - iph->ihl * 4;
+	struct iphdr iph;
+
+	if (skb_copy_bits(skb, iphoff, &iph, sizeof(iph)) < 0) {
+		printk("TRUNCATED");
+		return;
+	}
 
 	/* Important fields:
 	 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
 	/* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
 	printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
-	       NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
+	       NIPQUAD(iph.saddr), NIPQUAD(iph.daddr));
 
 	/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
 	printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
-	       ntohs(iph->tot_len), iph->tos & IPTOS_TOS_MASK,
-	       iph->tos & IPTOS_PREC_MASK, iph->ttl, ntohs(iph->id));
+	       ntohs(iph.tot_len), iph.tos & IPTOS_TOS_MASK,
+	       iph.tos & IPTOS_PREC_MASK, iph.ttl, ntohs(iph.id));
 
 	/* Max length: 6 "CE DF MF " */
-	if (ntohs(iph->frag_off) & IP_CE)
+	if (ntohs(iph.frag_off) & IP_CE)
 		printk("CE ");
-	if (ntohs(iph->frag_off) & IP_DF)
+	if (ntohs(iph.frag_off) & IP_DF)
 		printk("DF ");
-	if (ntohs(iph->frag_off) & IP_MF)
+	if (ntohs(iph.frag_off) & IP_MF)
 		printk("MF ");
 
 	/* Max length: 11 "FRAG:65535 " */
-	if (ntohs(iph->frag_off) & IP_OFFSET)
-		printk("FRAG:%u ", ntohs(iph->frag_off) & IP_OFFSET);
+	if (ntohs(iph.frag_off) & IP_OFFSET)
+		printk("FRAG:%u ", ntohs(iph.frag_off) & IP_OFFSET);
 
 	if ((info->logflags & IPT_LOG_IPOPT)
-	    && iph->ihl * 4 != sizeof(struct iphdr)) {
-		unsigned int i;
+	    && iph.ihl * 4 != sizeof(struct iphdr)) {
+		unsigned char opt[4 * 15 - sizeof(struct iphdr)];
+		unsigned int i, optsize;
+
+		optsize = iph.ihl * 4 - sizeof(struct iphdr);
+		if (skb_copy_bits(skb, iphoff+sizeof(iph), opt, optsize) < 0) {
+			printk("TRUNCATED");
+			return;
+		}
 
 		/* Max length: 127 "OPT (" 15*4*2chars ") " */
 		printk("OPT (");
-		for (i = sizeof(struct iphdr); i < iph->ihl * 4; i++)
-			printk("%02X", ((u_int8_t *)iph)[i]);
+		for (i = 0; i < optsize; i++)
+			printk("%02X", opt[i]);
 		printk(") ");
 	}
 
-	switch (iph->protocol) {
+	switch (iph.protocol) {
 	case IPPROTO_TCP: {
-		struct tcphdr *tcph = protoh;
+		struct tcphdr tcph;
 
 		/* Max length: 10 "PROTO=TCP " */
 		printk("PROTO=TCP ");
 
-		if (ntohs(iph->frag_off) & IP_OFFSET)
+		if (ntohs(iph.frag_off) & IP_OFFSET)
 			break;
 
 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		if (datalen < sizeof (*tcph)) {
-			printk("INCOMPLETE [%u bytes] ", datalen);
+		if (skb_copy_bits(skb, iphoff+iph.ihl*4, &tcph, sizeof(tcph))
+		    < 0) {
+			printk("INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - iph.ihl*4);
 			break;
 		}
 
 		/* Max length: 20 "SPT=65535 DPT=65535 " */
 		printk("SPT=%u DPT=%u ",
-		       ntohs(tcph->source), ntohs(tcph->dest));
+		       ntohs(tcph.source), ntohs(tcph.dest));
 		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 		if (info->logflags & IPT_LOG_TCPSEQ)
 			printk("SEQ=%u ACK=%u ",
-			       ntohl(tcph->seq), ntohl(tcph->ack_seq));
+			       ntohl(tcph.seq), ntohl(tcph.ack_seq));
 		/* Max length: 13 "WINDOW=65535 " */
-		printk("WINDOW=%u ", ntohs(tcph->window));
+		printk("WINDOW=%u ", ntohs(tcph.window));
 		/* Max length: 9 "RES=0x3F " */
-		printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(tcph) & TCP_RESERVED_BITS) >> 22));
+		printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(&tcph) & TCP_RESERVED_BITS) >> 22));
 		/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
-		if (tcph->cwr)
+		if (tcph.cwr)
 			printk("CWR ");
-		if (tcph->ece)
+		if (tcph.ece)
 			printk("ECE ");
-		if (tcph->urg)
+		if (tcph.urg)
 			printk("URG ");
-		if (tcph->ack)
+		if (tcph.ack)
 			printk("ACK ");
-		if (tcph->psh)
+		if (tcph.psh)
 			printk("PSH ");
-		if (tcph->rst)
+		if (tcph.rst)
 			printk("RST ");
-		if (tcph->syn)
+		if (tcph.syn)
 			printk("SYN ");
-		if (tcph->fin)
+		if (tcph.fin)
 			printk("FIN ");
 		/* Max length: 11 "URGP=65535 " */
-		printk("URGP=%u ", ntohs(tcph->urg_ptr));
+		printk("URGP=%u ", ntohs(tcph.urg_ptr));
 
 		if ((info->logflags & IPT_LOG_TCPOPT)
-		    && tcph->doff * 4 != sizeof(struct tcphdr)) {
-			unsigned int i;
+		    && tcph.doff * 4 != sizeof(struct tcphdr)) {
+			unsigned char opt[4 * 15 - sizeof(struct tcphdr)];
+			unsigned int i, optsize;
+
+			optsize = tcph.doff * 4 - sizeof(struct tcphdr);
+			if (skb_copy_bits(skb, iphoff+iph.ihl*4 + sizeof(tcph),
+					  opt, optsize) < 0) {
+				printk("TRUNCATED");
+				return;
+			}
 
 			/* Max length: 127 "OPT (" 15*4*2chars ") " */
 			printk("OPT (");
-			for (i =sizeof(struct tcphdr); i < tcph->doff * 4; i++)
-				printk("%02X", ((u_int8_t *)tcph)[i]);
+			for (i = 0; i < optsize; i++)
+				printk("%02X", opt[i]);
 			printk(") ");
 		}
 		break;
 	}
 	case IPPROTO_UDP: {
-		struct udphdr *udph = protoh;
+		struct udphdr udph;
 
 		/* Max length: 10 "PROTO=UDP " */
 		printk("PROTO=UDP ");
 
-		if (ntohs(iph->frag_off) & IP_OFFSET)
+		if (ntohs(iph.frag_off) & IP_OFFSET)
 			break;
 
 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		if (datalen < sizeof (*udph)) {
-			printk("INCOMPLETE [%u bytes] ", datalen);
+		if (skb_copy_bits(skb, iphoff+iph.ihl*4, &udph, sizeof(udph))
+		    < 0) {
+			printk("INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - iph.ihl*4);
 			break;
 		}
 
 		/* Max length: 20 "SPT=65535 DPT=65535 " */
 		printk("SPT=%u DPT=%u LEN=%u ",
-		       ntohs(udph->source), ntohs(udph->dest),
-		       ntohs(udph->len));
+		       ntohs(udph.source), ntohs(udph.dest),
+		       ntohs(udph.len));
 		break;
 	}
 	case IPPROTO_ICMP: {
-		struct icmphdr *icmph = protoh;
+		struct icmphdr icmph;
 		static size_t required_len[NR_ICMP_TYPES+1]
 			= { [ICMP_ECHOREPLY] = 4,
 			    [ICMP_DEST_UNREACH]
@@ -171,89 +195,93 @@ static void dump_packet(const struct ipt_log_info *info,
 		/* Max length: 11 "PROTO=ICMP " */
 		printk("PROTO=ICMP ");
 
-		if (ntohs(iph->frag_off) & IP_OFFSET)
+		if (ntohs(iph.frag_off) & IP_OFFSET)
 			break;
 
 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		if (datalen < 4) {
-			printk("INCOMPLETE [%u bytes] ", datalen);
+		if (skb_copy_bits(skb, iphoff+iph.ihl*4, &icmph, sizeof(icmph))
+		    < 0) {
+			printk("INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - iph.ihl*4);
 			break;
 		}
 
 		/* Max length: 18 "TYPE=255 CODE=255 " */
-		printk("TYPE=%u CODE=%u ", icmph->type, icmph->code);
+		printk("TYPE=%u CODE=%u ", icmph.type, icmph.code);
 
 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		if (icmph->type <= NR_ICMP_TYPES
-		    && required_len[icmph->type]
-		    && datalen < required_len[icmph->type]) {
-			printk("INCOMPLETE [%u bytes] ", datalen);
+		if (icmph.type <= NR_ICMP_TYPES
+		    && required_len[icmph.type]
+		    && skb->len-iphoff-iph.ihl*4 < required_len[icmph.type]) {
+			printk("INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - iph.ihl*4);
 			break;
 		}
 
-		switch (icmph->type) {
+		switch (icmph.type) {
 		case ICMP_ECHOREPLY:
 		case ICMP_ECHO:
 			/* Max length: 19 "ID=65535 SEQ=65535 " */
 			printk("ID=%u SEQ=%u ",
-			       ntohs(icmph->un.echo.id),
-			       ntohs(icmph->un.echo.sequence));
+			       ntohs(icmph.un.echo.id),
+			       ntohs(icmph.un.echo.sequence));
 			break;
 
 		case ICMP_PARAMETERPROB:
 			/* Max length: 14 "PARAMETER=255 " */
 			printk("PARAMETER=%u ",
-			       ntohl(icmph->un.gateway) >> 24);
+			       ntohl(icmph.un.gateway) >> 24);
 			break;
 		case ICMP_REDIRECT:
 			/* Max length: 24 "GATEWAY=255.255.255.255 " */
-			printk("GATEWAY=%u.%u.%u.%u ", NIPQUAD(icmph->un.gateway));
+			printk("GATEWAY=%u.%u.%u.%u ",
+			       NIPQUAD(icmph.un.gateway));
 			/* Fall through */
 		case ICMP_DEST_UNREACH:
 		case ICMP_SOURCE_QUENCH:
 		case ICMP_TIME_EXCEEDED:
 			/* Max length: 3+maxlen */
-			if (recurse) {
+			if (!iphoff) { /* Only recurse once. */
 				printk("[");
-				dump_packet(info,
-					    (struct iphdr *)(icmph + 1),
-					    datalen-sizeof(struct icmphdr),
-					    0);
+				dump_packet(info, skb,
+					    iphoff + iph.ihl*4+sizeof(icmph));
 				printk("] ");
 			}
 
 			/* Max length: 10 "MTU=65535 " */
-			if (icmph->type == ICMP_DEST_UNREACH
-			    && icmph->code == ICMP_FRAG_NEEDED)
-				printk("MTU=%u ", ntohs(icmph->un.frag.mtu));
+			if (icmph.type == ICMP_DEST_UNREACH
+			    && icmph.code == ICMP_FRAG_NEEDED)
+				printk("MTU=%u ", ntohs(icmph.un.frag.mtu));
 		}
 		break;
 	}
 	/* Max Length */
 	case IPPROTO_AH:
 	case IPPROTO_ESP: {
-		struct esphdr *esph = protoh;
-		int esp= (iph->protocol==IPPROTO_ESP);
+		struct esphdr esph;
+		int esp = (iph.protocol==IPPROTO_ESP);
 
 		/* Max length: 10 "PROTO=ESP " */
 		printk("PROTO=%s ",esp? "ESP" : "AH");
 
-		if (ntohs(iph->frag_off) & IP_OFFSET)
+		if (ntohs(iph.frag_off) & IP_OFFSET)
 			break;
 
 		/* Max length: 25 "INCOMPLETE [65535 bytes] " */
-		if (datalen < sizeof (*esph)) {
-			printk("INCOMPLETE [%u bytes] ", datalen);
+		if (skb_copy_bits(skb, iphoff+iph.ihl*4, &esph, sizeof(esph))
+		    < 0) {
+			printk("INCOMPLETE [%u bytes] ",
+			       skb->len - iphoff - iph.ihl*4);
 			break;
 		}
 
 		/* Length: 15 "SPI=0xF1234567 " */
-		printk("SPI=0x%x ", ntohl(esph->spi) );
+		printk("SPI=0x%x ", ntohl(esph.spi));
 		break;
 	}
 	/* Max length: 10 "PROTO 255 " */
 	default:
-		printk("PROTO=%u ", iph->protocol);
+		printk("PROTO=%u ", iph.protocol);
 	}
 
 	/* Proto    Max log string length */
@@ -272,13 +300,12 @@ static void dump_packet(const struct ipt_log_info *info,
 
 static unsigned int
 ipt_log_target(struct sk_buff **pskb,
-	       unsigned int hooknum,
 	       const struct net_device *in,
 	       const struct net_device *out,
+	       unsigned int hooknum,
 	       const void *targinfo,
 	       void *userinfo)
 {
-	struct iphdr *iph = (*pskb)->nh.iph;
 	const struct ipt_log_info *loginfo = targinfo;
 	char level_string[4] = "< >";
 
@@ -304,7 +331,8 @@ ipt_log_target(struct sk_buff **pskb,
 	if (in && !out) {
 		/* MAC logging for input chain only. */
 		printk("MAC=");
-		if ((*pskb)->dev && (*pskb)->dev->hard_header_len && (*pskb)->mac.raw != (void*)iph) {
+		if ((*pskb)->dev && (*pskb)->dev->hard_header_len
+		    && (*pskb)->mac.raw != (void*)(*pskb)->nh.iph) {
 			int i;
 			unsigned char *p = (*pskb)->mac.raw;
 			for (i = 0; i < (*pskb)->dev->hard_header_len; i++,p++)
@@ -315,7 +343,7 @@ ipt_log_target(struct sk_buff **pskb,
 			printk(" ");
 	}
 
-	dump_packet(loginfo, iph, (*pskb)->len, 1);
+	dump_packet(loginfo, *pskb, 0);
 	printk("\n");
 	spin_unlock_bh(&log_lock);
 

net/ipv4/netfilter/ipt_MARK.c

@@ -9,9 +9,9 @@
 
 static unsigned int
 target(struct sk_buff **pskb,
-       unsigned int hooknum,
        const struct net_device *in,
        const struct net_device *out,
+       unsigned int hooknum,
        const void *targinfo,
        void *userinfo)
 {

net/ipv4/netfilter/ipt_MASQUERADE.c

@@ -57,9 +57,9 @@ masquerade_check(const char *tablename,
 
 static unsigned int
 masquerade_target(struct sk_buff **pskb,
-		  unsigned int hooknum,
 		  const struct net_device *in,
 		  const struct net_device *out,
+		  unsigned int hooknum,
 		  const void *targinfo,
 		  void *userinfo)
 {

net/ipv4/netfilter/ipt_MIRROR.c

@@ -65,18 +65,22 @@ static int route_mirror(struct sk_buff *skb)
 	return 0;
 }
 
-static void
-ip_rewrite(struct sk_buff *skb)
+static int ip_rewrite(struct sk_buff **pskb)
 {
-	struct iphdr *iph = skb->nh.iph;
-	u32 odaddr = iph->saddr;
-	u32 osaddr = iph->daddr;
+	u32 odaddr, osaddr;
+
+	if (!skb_ip_make_writable(pskb, sizeof(struct iphdr)))
+		return 0;
 
-	skb->nfcache |= NFC_ALTERED;
+	odaddr = (*pskb)->nh.iph->saddr;
+	osaddr = (*pskb)->nh.iph->daddr;
+
+	(*pskb)->nfcache |= NFC_ALTERED;
 
 	/* Rewrite IP header */
-	iph->daddr = odaddr;
-	iph->saddr = osaddr;
+	(*pskb)->nh.iph->daddr = odaddr;
+	(*pskb)->nh.iph->saddr = osaddr;
+	return 1;
 }
 
 /* Stolen from ip_finish_output2 */
@@ -100,29 +104,28 @@ static void ip_direct_send(struct sk_buff *skb)
 }
 
 static unsigned int ipt_mirror_target(struct sk_buff **pskb,
-				      unsigned int hooknum,
 				      const struct net_device *in,
 				      const struct net_device *out,
+				      unsigned int hooknum,
 				      const void *targinfo,
 				      void *userinfo)
 {
-	if (((*pskb)->dst != NULL) &&
-	    route_mirror(*pskb)) {
-
-		ip_rewrite(*pskb);
+	if (((*pskb)->dst != NULL) && route_mirror(*pskb)) {
+		if (!ip_rewrite(pskb))
+			return NF_DROP;
 
 		/* If we are not at FORWARD hook (INPUT/PREROUTING),
 		 * the TTL isn't decreased by the IP stack */
 		if (hooknum != NF_IP_FORWARD) {
-			struct iphdr *iph = (*pskb)->nh.iph;
-			if (iph->ttl <= 1) {
+			if ((*pskb)->nh.iph->ttl <= 1) {
 				/* this will traverse normal stack, and 
 				 * thus call conntrack on the icmp packet */
 				icmp_send(*pskb, ICMP_TIME_EXCEEDED, 
 					  ICMP_EXC_TTL, 0);
 				return NF_DROP;
 			}
-			ip_decrease_ttl(iph);
+			/* Made writable by ip_rewrite */
+			ip_decrease_ttl((*pskb)->nh.iph);
 		}
 
 		/* Don't let conntrack code see this packet:

net/ipv4/netfilter/ipt_REDIRECT.c

@@ -53,9 +53,9 @@ redirect_check(const char *tablename,
 
 static unsigned int
 redirect_target(struct sk_buff **pskb,
-		unsigned int hooknum,
 		const struct net_device *in,
 		const struct net_device *out,
+		unsigned int hooknum,
 		const void *targinfo,
 		void *userinfo)
 {

net/ipv4/netfilter/ipt_REJECT.c

@@ -29,152 +29,140 @@ static void connection_attach(struct sk_buff *new_skb, struct nf_ct_info *nfct)
 	void (*attach)(struct sk_buff *, struct nf_ct_info *);
 
 	/* Avoid module unload race with ip_ct_attach being NULLed out */
-	if (nfct && (attach = ip_ct_attach) != NULL)
+	if (nfct && (attach = ip_ct_attach) != NULL) {
+		mb(); /* Just to be sure: must be read before executing this */
 		attach(new_skb, nfct);
+	}
 }
 
 /* Send RST reply */
-static void send_reset(struct sk_buff *oldskb, int local)
+static unsigned int send_reset(struct sk_buff **pskb, int local)
 {
-	struct sk_buff *nskb;
-	struct tcphdr *otcph, *tcph;
+	struct tcphdr tcph;
 	struct rtable *rt;
-	unsigned int otcplen;
 	u_int16_t tmp_port;
 	u_int32_t tmp_addr;
-	int needs_ack;
-	int hh_len;
+	int needs_ack, hh_len, datalen;
+	struct nf_ct_info *oldnfct;
 
-	/* IP header checks: fragment, too short. */
-	if (oldskb->nh.iph->frag_off & htons(IP_OFFSET)
-	    || oldskb->len < (oldskb->nh.iph->ihl<<2) + sizeof(struct tcphdr))
-		return;
+	/* No RSTs for fragments. */
+	if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET))
+		return NF_DROP;
 
-	otcph = (struct tcphdr *)((u_int32_t*)oldskb->nh.iph + oldskb->nh.iph->ihl);
-	otcplen = oldskb->len - oldskb->nh.iph->ihl*4;
+	if (skb_copy_bits(*pskb, (*pskb)->nh.iph->ihl*4,
+			  &tcph, sizeof(tcph)) < 0)
+		return NF_DROP;
 
 	/* No RST for RST. */
-	if (otcph->rst)
-		return;
-
-	/* Check checksum. */
-	if (tcp_v4_check(otcph, otcplen, oldskb->nh.iph->saddr,
-			 oldskb->nh.iph->daddr,
-			 csum_partial((char *)otcph, otcplen, 0)) != 0)
-		return;
-
+	if (tcph.rst)
+		return NF_DROP;
 
+	/* FIXME: Check checksum. */
 	{
 		struct flowi fl = { .nl_u = { .ip4_u =
-					      { .daddr = oldskb->nh.iph->saddr,
+					      { .daddr = (*pskb)->nh.iph->saddr,
 						.saddr = (local ?
-							  oldskb->nh.iph->daddr :
+							  (*pskb)->nh.iph->daddr :
 							  0),
-						.tos = RT_TOS(oldskb->nh.iph->tos) } } };
+						.tos = RT_TOS((*pskb)->nh.iph->tos) } } };
 
 		/* Routing: if not headed for us, route won't like source */
 		if (ip_route_output_key(&rt, &fl))
-			return;
+			return NF_DROP;
 
 		hh_len = (rt->u.dst.dev->hard_header_len + 15)&~15;
 	}
 
-
-	/* Copy skb (even if skb is about to be dropped, we can't just
-           clone it because there may be other things, such as tcpdump,
-           interested in it). We also need to expand headroom in case
-	   hh_len of incoming interface < hh_len of outgoing interface */
-	nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
-			       GFP_ATOMIC);
-	if (!nskb) {
-		dst_release(&rt->u.dst);
-		return;
+	/* We're going to flip the header around, drop options and data. */
+	if (!skb_ip_make_writable(pskb, (*pskb)->nh.iph->ihl*4+sizeof(tcph))) {
+		ip_rt_put(rt);
+		return NF_DROP;
 	}
 
-	dst_release(nskb->dst);
-	nskb->dst = &rt->u.dst;
+	(*pskb)->h.th = (void *)(*pskb)->nh.iph + sizeof(tcph);
+	datalen = (*pskb)->len - (*pskb)->nh.iph->ihl*4 - tcph.doff*4;
+
+	/* Change over route. */
+	dst_release((*pskb)->dst);
+	(*pskb)->dst = &rt->u.dst;
 
 	/* This packet will not be the same as the other: clear nf fields */
-	nf_conntrack_put(nskb->nfct);
-	nskb->nfct = NULL;
-	nskb->nfcache = 0;
+	(*pskb)->nfcache = 0;
 #ifdef CONFIG_NETFILTER_DEBUG
-	nskb->nf_debug = 0;
+	(*pskb)->nf_debug = 0;
 #endif
-	nskb->nfmark = 0;
-
-	tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);
+	(*pskb)->nfmark = 0;
 
 	/* Swap source and dest */
-	tmp_addr = nskb->nh.iph->saddr;
-	nskb->nh.iph->saddr = nskb->nh.iph->daddr;
-	nskb->nh.iph->daddr = tmp_addr;
-	tmp_port = tcph->source;
-	tcph->source = tcph->dest;
-	tcph->dest = tmp_port;
+	tmp_addr = (*pskb)->nh.iph->saddr;
+	(*pskb)->nh.iph->saddr = (*pskb)->nh.iph->daddr;
+	(*pskb)->nh.iph->daddr = tmp_addr;
+	tmp_port = (*pskb)->h.th->source;
+	(*pskb)->h.th->source = (*pskb)->h.th->dest;
+	(*pskb)->h.th->dest = tmp_port;
 
 	/* Truncate to length (no data) */
-	tcph->doff = sizeof(struct tcphdr)/4;
-	skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
-	nskb->nh.iph->tot_len = htons(nskb->len);
+	(*pskb)->h.th->doff = sizeof(struct tcphdr)/4;
+	skb_trim(*pskb, (*pskb)->nh.iph->ihl*4 + sizeof(struct tcphdr));
+	(*pskb)->nh.iph->tot_len = htons((*pskb)->len);
 
-	if (tcph->ack) {
+	if ((*pskb)->h.th->ack) {
 		needs_ack = 0;
-		tcph->seq = otcph->ack_seq;
-		tcph->ack_seq = 0;
+		(*pskb)->h.th->seq = tcph.ack_seq;
+		(*pskb)->h.th->ack_seq = 0;
 	} else {
 		needs_ack = 1;
-		tcph->ack_seq = htonl(ntohl(otcph->seq) + otcph->syn + otcph->fin
-				      + otcplen - (otcph->doff<<2));
-		tcph->seq = 0;
+		(*pskb)->h.th->ack_seq = htonl(ntohl(tcph.seq)
+						 + tcph.syn + tcph.fin
+						 + datalen);
+		(*pskb)->h.th->seq = 0;
 	}
 
 	/* Reset flags */
-	((u_int8_t *)tcph)[13] = 0;
-	tcph->rst = 1;
-	tcph->ack = needs_ack;
+	memset((*pskb)->h.raw + 13, 0, 1);
+	(*pskb)->h.th->rst = 1;
+	(*pskb)->h.th->ack = needs_ack;
 
-	tcph->window = 0;
-	tcph->urg_ptr = 0;
+	(*pskb)->h.th->window = 0;
+	(*pskb)->h.th->urg_ptr = 0;
 
 	/* Adjust TCP checksum */
-	tcph->check = 0;
-	tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
-				   nskb->nh.iph->saddr,
-				   nskb->nh.iph->daddr,
-				   csum_partial((char *)tcph,
+	(*pskb)->h.th->check = 0;
+	(*pskb)->h.th->check
+		= tcp_v4_check((*pskb)->h.th,
+			       sizeof(struct tcphdr),
+			       (*pskb)->nh.iph->saddr,
+			       (*pskb)->nh.iph->daddr,
+			       csum_partial((*pskb)->h.raw,
 					    sizeof(struct tcphdr), 0));
 
 	/* Adjust IP TTL, DF */
-	nskb->nh.iph->ttl = MAXTTL;
+	(*pskb)->nh.iph->ttl = MAXTTL;
 	/* Set DF, id = 0 */
-	nskb->nh.iph->frag_off = htons(IP_DF);
-	nskb->nh.iph->id = 0;
+	(*pskb)->nh.iph->frag_off = htons(IP_DF);
+	(*pskb)->nh.iph->id = 0;
 
 	/* Adjust IP checksum */
-	nskb->nh.iph->check = 0;
-	nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph, 
-					   nskb->nh.iph->ihl);
+	(*pskb)->nh.iph->check = 0;
+	(*pskb)->nh.iph->check = ip_fast_csum((*pskb)->nh.raw, 
+					      (*pskb)->nh.iph->ihl);
 
 	/* "Never happens" */
-	if (nskb->len > dst_pmtu(nskb->dst))
-		goto free_nskb;
+	if ((*pskb)->len > dst_pmtu((*pskb)->dst))
+		return NF_DROP;
 
-	connection_attach(nskb, oldskb->nfct);
+	/* Related to old connection. */
+	oldnfct = (*pskb)->nfct;
+	connection_attach(*pskb, oldnfct);
+	nf_conntrack_put(oldnfct);
 
-	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
+	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, *pskb, NULL, (*pskb)->dst->dev,
 		ip_finish_output);
-	return;
-
- free_nskb:
-	kfree_skb(nskb);
+	return NF_STOLEN;
 }
 
-static void send_unreach(struct sk_buff *skb_in, int code)
+static void send_unreach(const struct sk_buff *skb_in, int code)
 {
-	struct iphdr *iph;
-	struct udphdr *udph;
-	struct icmphdr *icmph;
 	struct sk_buff *nskb;
 	u32 saddr;
 	u8 tos;
@@ -189,8 +177,6 @@ static void send_unreach(struct sk_buff *skb_in, int code)
 	if (!xrlim_allow(&rt->u.dst, 1*HZ))
 		return;
 
-	iph = skb_in->nh.iph;
-
 	/* No replies to physical multicast/broadcast */
 	if (skb_in->pkt_type!=PACKET_HOST)
 		return;
@@ -200,46 +186,41 @@ static void send_unreach(struct sk_buff *skb_in, int code)
 		return;
 
 	/* Only reply to fragment 0. */
-	if (iph->frag_off&htons(IP_OFFSET))
+	if (skb_in->nh.iph->frag_off&htons(IP_OFFSET))
 		return;
 
-	/* if UDP checksum is set, verify it's correct */
-	if (iph->protocol == IPPROTO_UDP
-	    && skb_in->tail-(u8*)iph >= sizeof(struct udphdr)) {
-		int datalen = skb_in->len - (iph->ihl<<2);
-		udph = (struct udphdr *)((char *)iph + (iph->ihl<<2));
-		if (udph->check
-		    && csum_tcpudp_magic(iph->saddr, iph->daddr,
-		                         datalen, IPPROTO_UDP,
-		                         csum_partial((char *)udph, datalen,
-		                                      0)) != 0)
+	/* Ensure we have at least 8 bytes of proto header. */
+	if (skb_in->len < skb_in->nh.iph->ihl*4 + 8)
 		return;
-	}
 
 	/* If we send an ICMP error to an ICMP error a mess would result.. */
-	if (iph->protocol == IPPROTO_ICMP
-	    && skb_in->tail-(u8*)iph >= sizeof(struct icmphdr)) {
-		icmph = (struct icmphdr *)((char *)iph + (iph->ihl<<2));
+	if (skb_in->nh.iph->protocol == IPPROTO_ICMP) {
+		struct icmphdr icmph;
+
+		if (skb_copy_bits(skb_in, skb_in->nh.iph->ihl*4,
+				  &icmph, sizeof(icmph)) < 0)
+			return;
+
 		/* Between echo-reply (0) and timestamp (13),
 		   everything except echo-request (8) is an error.
 		   Also, anything greater than NR_ICMP_TYPES is
 		   unknown, and hence should be treated as an error... */
-		if ((icmph->type < ICMP_TIMESTAMP
-		     && icmph->type != ICMP_ECHOREPLY
-		     && icmph->type != ICMP_ECHO)
-		    || icmph->type > NR_ICMP_TYPES)
+		if ((icmph.type < ICMP_TIMESTAMP
+		     && icmph.type != ICMP_ECHOREPLY
+		     && icmph.type != ICMP_ECHO)
+		    || icmph.type > NR_ICMP_TYPES)
 			return;
 	}
 
-	saddr = iph->daddr;
+	saddr = skb_in->nh.iph->daddr;
 	if (!(rt->rt_flags & RTCF_LOCAL))
 		saddr = 0;
 
-	tos = (iph->tos & IPTOS_TOS_MASK) | IPTOS_PREC_INTERNETCONTROL;
-
+	tos = (skb_in->nh.iph->tos & IPTOS_TOS_MASK)
+		| IPTOS_PREC_INTERNETCONTROL;
 	{
 		struct flowi fl = { .nl_u = { .ip4_u =
-					      { .daddr = iph->saddr,
+					      { .daddr = skb_in->nh.iph->saddr,
 						.saddr = saddr,
 						.tos = RT_TOS(tos) } } };
 		if (ip_route_output_key(&rt, &fl))
@@ -266,40 +247,38 @@ static void send_unreach(struct sk_buff *skb_in, int code)
 	skb_reserve(nskb, hh_len);
 
 	/* Set up IP header */
-	iph = nskb->nh.iph
-		= (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
-	iph->version=4;
-	iph->ihl=5;
-	iph->tos=tos;
-	iph->tot_len = htons(length);
+	nskb->nh.iph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
+	nskb->nh.iph->version=4;
+	nskb->nh.iph->ihl=5;
+	nskb->nh.iph->tos=tos;
+	nskb->nh.iph->tot_len = htons(length);
 
 	/* PMTU discovery never applies to ICMP packets. */
-	iph->frag_off = 0;
+	nskb->nh.iph->frag_off = 0;
 
-	iph->ttl = MAXTTL;
-	ip_select_ident(iph, &rt->u.dst, NULL);
-	iph->protocol=IPPROTO_ICMP;
-	iph->saddr=rt->rt_src;
-	iph->daddr=rt->rt_dst;
-	iph->check=0;
-	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
+	nskb->nh.iph->ttl = MAXTTL;
+	ip_select_ident(nskb->nh.iph, &rt->u.dst, NULL);
+	nskb->nh.iph->protocol=IPPROTO_ICMP;
+	nskb->nh.iph->saddr=rt->rt_src;
+	nskb->nh.iph->daddr=rt->rt_dst;
+	nskb->nh.iph->check=0;
+	nskb->nh.iph->check = ip_fast_csum(nskb->nh.raw,
+					   nskb->nh.iph->ihl);
 
 	/* Set up ICMP header. */
-	icmph = nskb->h.icmph
-		= (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
-	icmph->type = ICMP_DEST_UNREACH;
-	icmph->code = code;	
-	icmph->un.gateway = 0;
-	icmph->checksum = 0;
+	nskb->h.icmph = (struct icmphdr *)skb_put(nskb,sizeof(struct icmphdr));
+	nskb->h.icmph->type = ICMP_DEST_UNREACH;
+	nskb->h.icmph->code = code;	
+	nskb->h.icmph->un.gateway = 0;
+	nskb->h.icmph->checksum = 0;
 	
 	/* Copy as much of original packet as will fit */
 	data = skb_put(nskb,
 		       length - sizeof(struct iphdr) - sizeof(struct icmphdr));
-	/* FIXME: won't work with nonlinear skbs --RR */
-	memcpy(data, skb_in->nh.iph,
+	skb_copy_bits(skb_in, 0, data,
 		      length - sizeof(struct iphdr) - sizeof(struct icmphdr));
-	icmph->checksum = ip_compute_csum((unsigned char *)icmph,
-					  length - sizeof(struct iphdr));
+	nskb->h.icmph->checksum = ip_compute_csum(nskb->h.raw,
+						  length-sizeof(struct iphdr));
 
 	connection_attach(nskb, skb_in->nfct);
 
@@ -308,9 +287,9 @@ static void send_unreach(struct sk_buff *skb_in, int code)
 }	
 
 static unsigned int reject(struct sk_buff **pskb,
-			   unsigned int hooknum,
 			   const struct net_device *in,
 			   const struct net_device *out,
+			   unsigned int hooknum,
 			   const void *targinfo,
 			   void *userinfo)
 {
@@ -344,7 +323,7 @@ static unsigned int reject(struct sk_buff **pskb,
     		send_unreach(*pskb, ICMP_HOST_ANO);
     		break;
 	case IPT_TCP_RESET:
-		send_reset(*pskb, hooknum == NF_IP_LOCAL_IN);
+		return send_reset(pskb, hooknum == NF_IP_LOCAL_IN);
 	case IPT_ICMP_ECHOREPLY:
 		/* Doesn't happen. */
 		break;

net/ipv4/netfilter/ipt_TCPMSS.c

@@ -36,9 +36,9 @@ optlen(const u_int8_t *opt, unsigned int offset)
 
 static unsigned int
 ipt_tcpmss_target(struct sk_buff **pskb,
-		  unsigned int hooknum,
 		  const struct net_device *in,
 		  const struct net_device *out,
+		  unsigned int hooknum,
 		  const void *targinfo,
 		  void *userinfo)
 {
@@ -49,15 +49,8 @@ ipt_tcpmss_target(struct sk_buff **pskb,
 	unsigned int i;
 	u_int8_t *opt;
 
-	/* raw socket (tcpdump) may have clone of incoming skb: don't
-	   disturb it --RR */
-	if (skb_cloned(*pskb) && !(*pskb)->sk) {
-		struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
-		if (!nskb)
+	if (!skb_ip_make_writable(pskb, (*pskb)->len))
 		return NF_DROP;
-		kfree_skb(*pskb);
-		*pskb = nskb;
-	}
 
 	iph = (*pskb)->nh.iph;
 	tcplen = (*pskb)->len - iph->ihl*4;

net/ipv4/netfilter/ipt_TOS.c

@@ -9,35 +9,30 @@
 
 static unsigned int
 target(struct sk_buff **pskb,
-       unsigned int hooknum,
        const struct net_device *in,
        const struct net_device *out,
+       unsigned int hooknum,
        const void *targinfo,
        void *userinfo)
 {
-	struct iphdr *iph = (*pskb)->nh.iph;
 	const struct ipt_tos_target_info *tosinfo = targinfo;
 
-	if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {
+	if (((*pskb)->nh.iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {
 		u_int16_t diffs[2];
 
-		/* raw socket (tcpdump) may have clone of incoming
-                   skb: don't disturb it --RR */
-		if (skb_cloned(*pskb) && !(*pskb)->sk) {
-			struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
-			if (!nskb)
+		if (!skb_ip_make_writable(pskb, sizeof(struct iphdr)))
 			return NF_DROP;
-			kfree_skb(*pskb);
-			*pskb = nskb;
-			iph = (*pskb)->nh.iph;
-		}
 
-		diffs[0] = htons(iph->tos) ^ 0xFFFF;
-		iph->tos = (iph->tos & IPTOS_PREC_MASK) | tosinfo->tos;
-		diffs[1] = htons(iph->tos);
-		iph->check = csum_fold(csum_partial((char *)diffs,
+		diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
+		(*pskb)->nh.iph->tos
+			= ((*pskb)->nh.iph->tos & IPTOS_PREC_MASK)
+			| tosinfo->tos;
+		diffs[1] = htons((*pskb)->nh.iph->tos);
+		(*pskb)->nh.iph->check
+			= csum_fold(csum_partial((char *)diffs,
 						 sizeof(diffs),
-		                                    iph->check^0xFFFF));
+						 (*pskb)->nh.iph->check
+						 ^0xFFFF));
 		(*pskb)->nfcache |= NFC_ALTERED;
 	}
 	return IPT_CONTINUE;

net/ipv4/netfilter/ipt_ULOG.c

@@ -155,9 +155,9 @@ struct sk_buff *ulog_alloc_skb(unsigned int size)
 }
 
 static unsigned int ipt_ulog_target(struct sk_buff **pskb,
-				    unsigned int hooknum,
 				    const struct net_device *in,
 				    const struct net_device *out,
+				    unsigned int hooknum,
 				    const void *targinfo, void *userinfo)
 {
 	ulog_buff_t *ub;
@@ -238,8 +238,9 @@ static unsigned int ipt_ulog_target(struct sk_buff **pskb,
 	else
 		pm->outdev_name[0] = '\0';
 
-	if (copy_len)
-		memcpy(pm->payload, (*pskb)->data, copy_len);
+	/* copy_len <= (*pskb)->len, so can't fail. */
+	if (skb_copy_bits(*pskb, 0, pm->payload, copy_len) < 0)
+		BUG();
 	
 	/* check if we are building multi-part messages */
 	if (ub->qlen > 1) {