[openwrt/openwrt] tcpdump: patch CVE-2020-8037

[LEDE Commits]

ynezz pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/5bb3cc749ee0d08d82acda3c084ff759f3829a91

commit 5bb3cc749ee0d08d82acda3c084ff759f3829a91
Author: Jan Pavlinec <jan.pavlinec at nic.cz>
AuthorDate: Wed Nov 25 02:04:00 2020 +0100

    tcpdump: patch CVE-2020-8037
    
    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 at nic.cz>
    [added missing commit description]
    Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 package/network/utils/tcpdump/Makefile             |  2 +-
 .../utils/tcpdump/patches/101-CVE-2020-8037.patch  | 47 ++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/package/network/utils/tcpdump/Makefile b/package/network/utils/tcpdump/Makefile
index 09b0b03766..3e4d9d2d73 100644
--- a/package/network/utils/tcpdump/Makefile
+++ b/package/network/utils/tcpdump/Makefile
@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=tcpdump
 PKG_VERSION:=4.9.3
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://www.us.tcpdump.org/release/ \
diff --git a/package/network/utils/tcpdump/patches/101-CVE-2020-8037.patch b/package/network/utils/tcpdump/patches/101-CVE-2020-8037.patch
new file mode 100644
index 0000000000..281854777d
--- /dev/null
+++ b/package/network/utils/tcpdump/patches/101-CVE-2020-8037.patch
@@ -0,0 +1,47 @@
+--- 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;