main/tcpdump: fix CVE-2020-8037

See: #12120

2 files changed, 71 insertions, 3 deletions

diff --git a/main/tcpdump/APKBUILD b/main/tcpdump/APKBUILD
index 944fae9fd9d..fb6473bc5ff 100644
--- a/main/tcpdump/APKBUILD
+++ b/main/tcpdump/APKBUILD
@@ -1,7 +1,7 @@
 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=tcpdump
 pkgver=4.9.3
-pkgrel=0
+pkgrel=1
 pkgdesc="A tool for network monitoring and data acquisition"
 url="http://www.tcpdump.org"
 arch="all"
@@ -9,9 +9,13 @@ license="BSD-3-Clause"
 options="!check" # fail on ppc64le
 makedepends="libpcap-dev openssl-dev perl"
 subpackages="$pkgname-doc"
-source="http://www.$pkgname.org/release/$pkgname-$pkgver.tar.gz"
+source="http://www.$pkgname.org/release/$pkgname-$pkgver.tar.gz
+	CVE-2020-8037.patch
+	"
 
 # secfixes:
+#   4.9.3-r1:
+#     - CVE-2020-8037
 #   4.9.3-r0:
 #     - CVE-2017-16808 (AoE)
 #     - CVE-2018-14468 (FrameRelay)
@@ -111,4 +115,5 @@ package() {
 	rm -f "$pkgdir"/usr/sbin/tcpdump.4*
 }
 
-sha512sums="3aec673f78b996a4df884b1240e5d0a26a2ca81ee7aca8a2e6d50255bb53476e008a5ced4409e278a956710d8a4d31d85bbb800c9f1aab92b0b1046b59292a22  tcpdump-4.9.3.tar.gz"
+sha512sums="3aec673f78b996a4df884b1240e5d0a26a2ca81ee7aca8a2e6d50255bb53476e008a5ced4409e278a956710d8a4d31d85bbb800c9f1aab92b0b1046b59292a22  tcpdump-4.9.3.tar.gz
+f53b5557ad2c68c28bbd6121b637ade43937ce4956fa9c2c8b187e8c62726c018509eb728f7f7479d078c9018f091f64114944b2d6106e6214662899f880445a  CVE-2020-8037.patch"
diff --git a/main/tcpdump/CVE-2020-8037.patch b/main/tcpdump/CVE-2020-8037.patch
new file mode 100644
index 00000000000..2852845eb74
--- /dev/null
+++ b/main/tcpdump/CVE-2020-8037.patch
@@ -0,0 +1,63 @@
+From 32027e199368dad9508965aae8cd8de5b6ab5231 Mon Sep 17 00:00:00 2001
+From: Guy Harris <guy@alum.mit.edu>
+Date: Sat, 18 Apr 2020 14:04:59 -0700
+Subject: [PATCH] PPP: When un-escaping, don't allocate a too-large buffer.
+
+The buffer should be big enough to hold the captured data, but it
+doesn't need to be big enough to hold the entire on-the-network packet,
+if we haven't captured all of it.
+
+(backported from commit e4add0b010ed6f2180dcb05a13026242ed935334)
+---
+ print-ppp.c | 18 ++++++++++++++----
+ 1 file changed, 14 insertions(+), 4 deletions(-)
+
+diff --git a/print-ppp.c b/print-ppp.c
+index 891761728..33fb03412 100644
+--- a/print-ppp.c
++++ b/print-ppp.c
+@@ -1367,19 +1367,29 @@ print_bacp_config_options(netdissect_options *ndo,
+ 	return 0;
+ }
+ 
++/*
++ * 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;
+ 
+@@ -1388,10 +1398,10 @@ 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;