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path: root/drivers/net/slip/slhc.c
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Diffstat (limited to 'drivers/net/slip/slhc.c')
-rw-r--r--drivers/net/slip/slhc.c126
1 files changed, 76 insertions, 50 deletions
diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
index 1252d9c726a7..ee9fd3a94b96 100644
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -75,30 +75,34 @@
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/timer.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
#include <net/checksum.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
static unsigned char *encode(unsigned char *cp, unsigned short n);
static long decode(unsigned char **cpp);
static unsigned char * put16(unsigned char *cp, unsigned short x);
static unsigned short pull16(unsigned char **cpp);
-/* Initialize compression data structure
+/* Allocate compression data structure
* slots must be in range 0 to 255 (zero meaning no compression)
+ * Returns pointer to structure or ERR_PTR() on error.
*/
struct slcompress *
slhc_init(int rslots, int tslots)
{
- register short i;
- register struct cstate *ts;
+ short i;
+ struct cstate *ts;
struct slcompress *comp;
+ if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
+ return ERR_PTR(-EINVAL);
+
comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL);
if (! comp)
goto out_fail;
- if ( rslots > 0 && rslots < 256 ) {
+ if (rslots > 0) {
size_t rsize = rslots * sizeof(struct cstate);
comp->rstate = kzalloc(rsize, GFP_KERNEL);
if (! comp->rstate)
@@ -106,7 +110,7 @@ slhc_init(int rslots, int tslots)
comp->rslot_limit = rslots - 1;
}
- if ( tslots > 0 && tslots < 256 ) {
+ if (tslots > 0) {
size_t tsize = tslots * sizeof(struct cstate);
comp->tstate = kzalloc(tsize, GFP_KERNEL);
if (! comp->tstate)
@@ -141,7 +145,7 @@ out_free2:
out_free:
kfree(comp);
out_fail:
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
@@ -149,7 +153,7 @@ out_fail:
void
slhc_free(struct slcompress *comp)
{
- if ( comp == NULLSLCOMPR )
+ if ( IS_ERR_OR_NULL(comp) )
return;
if ( comp->tstate != NULLSLSTATE )
@@ -202,7 +206,7 @@ pull16(unsigned char **cpp)
static long
decode(unsigned char **cpp)
{
- register int x;
+ int x;
x = *(*cpp)++;
if(x == 0){
@@ -223,14 +227,14 @@ int
slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
unsigned char *ocp, unsigned char **cpp, int compress_cid)
{
- register struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]);
- register struct cstate *lcs = ocs;
- register struct cstate *cs = lcs->next;
- register unsigned long deltaS, deltaA;
- register short changes = 0;
- int hlen;
+ struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]);
+ struct cstate *lcs = ocs;
+ struct cstate *cs = lcs->next;
+ unsigned long deltaS, deltaA;
+ short changes = 0;
+ int nlen, hlen;
unsigned char new_seq[16];
- register unsigned char *cp = new_seq;
+ unsigned char *cp = new_seq;
struct iphdr *ip;
struct tcphdr *th, *oth;
__sum16 csum;
@@ -244,6 +248,8 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
return isize;
ip = (struct iphdr *) icp;
+ if (ip->version != 4 || ip->ihl < 5)
+ return isize;
/* Bail if this packet isn't TCP, or is an IP fragment */
if (ip->protocol != IPPROTO_TCP || (ntohs(ip->frag_off) & 0x3fff)) {
@@ -254,10 +260,14 @@ slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
comp->sls_o_tcp++;
return isize;
}
- /* Extract TCP header */
+ nlen = ip->ihl * 4;
+ if (isize < nlen + sizeof(*th))
+ return isize;
- th = (struct tcphdr *)(((unsigned char *)ip) + ip->ihl*4);
- hlen = ip->ihl*4 + th->doff*4;
+ th = (struct tcphdr *)(icp + nlen);
+ if (th->doff < sizeof(struct tcphdr) / 4)
+ return isize;
+ hlen = nlen + th->doff * 4;
/* Bail if the TCP packet isn't `compressible' (i.e., ACK isn't set or
* some other control bit is set). Also uncompressible if
@@ -315,7 +325,7 @@ found:
* Found it -- move to the front on the connection list.
*/
if(lcs == ocs) {
- /* found at most recently used */
+ /* found at most recently used */
} else if (cs == ocs) {
/* found at least recently used */
comp->xmit_oldest = lcs->cs_this;
@@ -396,7 +406,6 @@ found:
ntohs(cs->cs_ip.tot_len) == hlen)
break;
goto uncompressed;
- break;
case SPECIAL_I:
case SPECIAL_D:
/* actual changes match one of our special case encodings --
@@ -483,11 +492,11 @@ uncompressed:
int
slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
{
- register int changes;
+ int changes;
long x;
- register struct tcphdr *thp;
- register struct iphdr *ip;
- register struct cstate *cs;
+ struct tcphdr *thp;
+ struct iphdr *ip;
+ struct cstate *cs;
int len, hdrlen;
unsigned char *cp = icp;
@@ -506,6 +515,10 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
if(x < 0 || x > comp->rslot_limit)
goto bad;
+ /* Check if the cstate is initialized */
+ if (!comp->rstate[x].initialized)
+ goto bad;
+
comp->flags &=~ SLF_TOSS;
comp->recv_current = x;
} else {
@@ -536,7 +549,7 @@ slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
switch(changes & SPECIALS_MASK){
case SPECIAL_I: /* Echoed terminal traffic */
{
- register short i;
+ short i;
i = ntohs(ip->tot_len) - hdrlen;
thp->ack_seq = htonl( ntohl(thp->ack_seq) + i);
thp->seq = htonl( ntohl(thp->seq) + i);
@@ -630,46 +643,58 @@ bad:
int
slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
{
- register 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 );
+ 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 */
comp->sls_i_badcheck++;
- return slhc_toss( comp );
+ return slhc_toss(comp);
}
- if(index > comp->rslot_limit) {
+ if (index > comp->rslot_limit) {
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
*/
@@ -738,4 +763,5 @@ EXPORT_SYMBOL(slhc_compress);
EXPORT_SYMBOL(slhc_uncompress);
EXPORT_SYMBOL(slhc_toss);
+MODULE_DESCRIPTION("Compression helpers for SLIP (serial line)");
MODULE_LICENSE("Dual BSD/GPL");
generated by cgit (git 2.34.1) at 2025-12-25 11:40:29 +0000