Unverified Commit fad05042 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
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!12791 slip: make slhc_remember() more robust against malicious packets 

Merge Pull Request from: @ci-robot 
 
PR sync from: Liu Jian <liujian56@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/VRD2WLZPLG6QEOKQ5HE4JZQ5NNQZN6DI/ 
 
https://gitee.com/src-openeuler/kernel/issues/IAYRFT 
 
Link:https://gitee.com/openeuler/kernel/pulls/12791

 

Reviewed-by: default avatarYue Haibing <yuehaibing@huawei.com>
Signed-off-by: default avatarZhang Peng <zhangpeng362@huawei.com>
parents e11dfd5f cbf5af12

drivers/net/slip/slhc.c

+34 −23
Original line number Diff line number Diff line
@@ -643,25 +643,32 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) 
int

slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)

{

	struct cstate *cs;

	unsigned ihl;



	const struct tcphdr *th;

	unsigned char index;

	struct iphdr *iph;

	struct cstate *cs;

	unsigned int ihl;



	if(isize < 20) {

		/* The packet is shorter than a legal IP header */

	/* The packet is shorter than a legal IP header.

	 * Also make sure isize is positive.

	 */

	if (isize < (int)sizeof(struct iphdr)) {

runt:

		comp->sls_i_runt++;

		return slhc_toss(comp);

	}

	iph = (struct iphdr *)icp;

	/* Peek at the IP header's IHL field to find its length */

	ihl = icp[0] & 0xf;

	if(ihl < 20 / 4){

		/* The IP header length field is too small */

		comp->sls_i_runt++;

		return slhc_toss( comp );

	}

	index = icp[9];

	icp[9] = IPPROTO_TCP;

	ihl = iph->ihl;

	/* The IP header length field is too small,

	 * or packet is shorter than the IP header followed

	 * by minimal tcp header.

	 */

	if (ihl < 5 || isize < ihl * 4 + sizeof(struct tcphdr))

		goto runt;



	index = iph->protocol;

	iph->protocol = IPPROTO_TCP;



	if (ip_fast_csum(icp, ihl)) {

		/* Bad IP header checksum; discard */
@@ -672,17 +679,21 @@ slhc_remember(struct slcompress *comp, unsigned char *icp, int isize) 
		comp->sls_i_error++;

		return slhc_toss(comp);

	}



	th = (struct tcphdr *)(icp + ihl * 4);

	if (th->doff < sizeof(struct tcphdr) / 4)

		goto runt;

	if (isize < ihl * 4 + th->doff * 4)

		goto runt;

	/* Update local state */

	cs = &comp->rstate[comp->recv_current = index];

	comp->flags &=~ SLF_TOSS;

	memcpy(&cs->cs_ip,icp,20);

	memcpy(&cs->cs_tcp,icp + ihl*4,20);

	memcpy(&cs->cs_ip, iph, sizeof(*iph));

	memcpy(&cs->cs_tcp, th, sizeof(*th));

	if (ihl > 5)

	  memcpy(cs->cs_ipopt, icp + sizeof(struct iphdr), (ihl - 5) * 4);

	if (cs->cs_tcp.doff > 5)

	  memcpy(cs->cs_tcpopt, icp + ihl*4 + sizeof(struct tcphdr), (cs->cs_tcp.doff - 5) * 4);

	cs->cs_hsize = ihl*2 + cs->cs_tcp.doff*2;

	  memcpy(cs->cs_ipopt, &iph[1], (ihl - 5) * 4);

	if (th->doff > 5)

	  memcpy(cs->cs_tcpopt, &th[1], (th->doff - 5) * 4);

	cs->cs_hsize = ihl*2 + th->doff*2;

	cs->initialized = true;

	/* Put headers back on packet

	 * Neither header checksum is recalculated