X-Git-Url: https://git.distorted.org.uk/~mdw/secnet/blobdiff_plain/779837e133a4740798015a1d7de6fbf6b4b1720f..6e3fd952d7052293905334a3bb3911c775222ea6:/slip.c

diff --git a/slip.c b/slip.c
index 0f62a69..aed2551 100644
--- a/slip.c
+++ b/slip.c
@@ -79,6 +79,9 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 	int outputchr;
 	enum { OUTPUT_END = 256, OUTPUT_NOTHING = 257 };
 
+	if (!st->buff->size)
+	    buffer_init(st->buff,calculate_max_start_pad());
+
 	if (st->pending_esc) {
 	    st->pending_esc=False;
 	    switch(buf[i]) {
@@ -115,7 +118,7 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 	if (st->ignoring_packet) {
 	    if (outputchr == OUTPUT_END) {
 		st->ignoring_packet=False;
-		buffer_init(st->buff,st->nl.max_start_pad);
+		st->buff->size=0;
 	    }
 	} else {
 	    if (outputchr == OUTPUT_END) {
@@ -123,7 +126,7 @@ static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
 		    st->netlink_to_tunnel(&st->nl,st->buff);
 		    BUF_ALLOC(st->buff,"userv_afterpoll");
 		}
-		buffer_init(st->buff,st->nl.max_start_pad);
+		st->buff->size=0;
 	    } else if (outputchr != OUTPUT_NOTHING) {
 		if (st->buff->size < st->buff->len) {
 		    buf_append_uint8(st->buff,outputchr);
@@ -210,6 +213,14 @@ static void userv_deliver_to_kernel(void *sst, struct buffer_if *buf)
 {
     struct userv *st=sst;
 
+    if (buf->size > st->slip.nl.mtu) {
+	Message(M_ERR,"%s: packet of size %"PRIu32" exceeds mtu %"PRIu32":"
+		" cannot be injected into kernel, dropped\n",
+		st->slip.nl.name, buf->size, st->slip.nl.mtu);
+	BUF_FREE(buf);
+	return;
+    }
+
     slip_stuff(&st->slip,buf,st->txfd);
 }