5bb3cc749e
This PR backports upstream fix for CVE-2020-8037. This fix is only relevant for tcpdump package, tcpdump-mini is not affeted by this issue. Signed-off-by: Jan Pavlinec <jan.pavlinec@nic.cz> [added missing commit description] Signed-off-by: Petr Štetiar <ynezz@true.cz>
48 lines
1.0 KiB
Diff
48 lines
1.0 KiB
Diff
--- a/print-ppp.c
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+++ b/print-ppp.c
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@@ -1368,19 +1368,29 @@ trunc:
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}
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#ifndef TCPDUMP_MINI
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+/*
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+ * Un-escape RFC 1662 PPP in HDLC-like framing, with octet escapes.
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+ * The length argument is the on-the-wire length, not the captured
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+ * length; we can only un-escape the captured part.
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+ */
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static void
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ppp_hdlc(netdissect_options *ndo,
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const u_char *p, int length)
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{
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+ u_int caplen = ndo->ndo_snapend - p;
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u_char *b, *t, c;
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const u_char *s;
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- int i, proto;
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+ u_int i;
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+ int proto;
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const void *se;
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+ if (caplen == 0)
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+ return;
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+
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if (length <= 0)
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return;
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- b = (u_char *)malloc(length);
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+ b = (u_char *)malloc(caplen);
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if (b == NULL)
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return;
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@@ -1389,10 +1399,10 @@ ppp_hdlc(netdissect_options *ndo,
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* Do this so that we dont overwrite the original packet
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* contents.
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*/
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- for (s = p, t = b, i = length; i > 0 && ND_TTEST(*s); i--) {
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+ for (s = p, t = b, i = caplen; i != 0; i--) {
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c = *s++;
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if (c == 0x7d) {
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- if (i <= 1 || !ND_TTEST(*s))
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+ if (i <= 1)
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break;
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i--;
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c = *s++ ^ 0x20;
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