openwrt/package/network/utils/tcpdump/patches/101-CVE-2020-8037.patch

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--- a/print-ppp.c
+++ b/print-ppp.c
@@ -1368,19 +1368,29 @@ trunc:
}
#ifndef TCPDUMP_MINI
+/*
+ * Un-escape RFC 1662 PPP in HDLC-like framing, with octet escapes.
+ * The length argument is the on-the-wire length, not the captured
+ * length; we can only un-escape the captured part.
+ */
static void
ppp_hdlc(netdissect_options *ndo,
const u_char *p, int length)
{
+ u_int caplen = ndo->ndo_snapend - p;
u_char *b, *t, c;
const u_char *s;
- int i, proto;
+ u_int i;
+ int proto;
const void *se;
+ if (caplen == 0)
+ return;
+
if (length <= 0)
return;
- b = (u_char *)malloc(length);
+ b = (u_char *)malloc(caplen);
if (b == NULL)
return;
@@ -1389,10 +1399,10 @@ ppp_hdlc(netdissect_options *ndo,
* Do this so that we dont overwrite the original packet
* contents.
*/
- for (s = p, t = b, i = length; i > 0 && ND_TTEST(*s); i--) {
+ for (s = p, t = b, i = caplen; i != 0; i--) {
c = *s++;
if (c == 0x7d) {
- if (i <= 1 || !ND_TTEST(*s))
+ if (i <= 1)
break;
i--;
c = *s++ ^ 0x20;