* [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037
@ 2020-11-13 20:21 Fabrice Fontaine
2020-11-14 13:18 ` Peter Korsgaard
2020-11-16 14:51 ` Peter Korsgaard
0 siblings, 2 replies; 3+ messages in thread
From: Fabrice Fontaine @ 2020-11-13 20:21 UTC (permalink / raw)
To: buildroot
The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a
large amount of memory.
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
...ng-don-t-allocate-a-too-large-buffer.patch | 67 +++++++++++++++++++
package/tcpdump/tcpdump.mk | 3 +
2 files changed, 70 insertions(+)
create mode 100644 package/tcpdump/0001-PPP-When-un-escaping-don-t-allocate-a-too-large-buffer.patch
diff --git a/package/tcpdump/0001-PPP-When-un-escaping-don-t-allocate-a-too-large-buffer.patch b/package/tcpdump/0001-PPP-When-un-escaping-don-t-allocate-a-too-large-buffer.patch
new file mode 100644
index 0000000000..9e8674ac90
--- /dev/null
+++ b/package/tcpdump/0001-PPP-When-un-escaping-don-t-allocate-a-too-large-buffer.patch
@@ -0,0 +1,67 @@
+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)
+
+[Retrieved from:
+https://github.com/the-tcpdump-group/tcpdump/commit/32027e199368dad9508965aae8cd8de5b6ab5231]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ 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;
diff --git a/package/tcpdump/tcpdump.mk b/package/tcpdump/tcpdump.mk
index 01a46b9b5f..8db35694ea 100644
--- a/package/tcpdump/tcpdump.mk
+++ b/package/tcpdump/tcpdump.mk
@@ -18,6 +18,9 @@ TCPDUMP_CONF_OPTS = \
$(if $(BR2_PACKAGE_TCPDUMP_SMB),--enable-smb,--disable-smb)
TCPDUMP_DEPENDENCIES = libpcap
+# 0001-PPP-When-un-escaping-don-t-allocate-a-too-large-buffer.patch
+TCPDUMP_IGNORE_CVES += CVE-2020-8037
+
ifeq ($(BR2_STATIC_LIBS),y)
TCPDUMP_CONF_OPTS += LIBS="`$(STAGING_DIR)/usr/bin/pcap-config --static --additional-libs`"
endif
--
2.28.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037
2020-11-13 20:21 [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037 Fabrice Fontaine
@ 2020-11-14 13:18 ` Peter Korsgaard
2020-11-16 14:51 ` Peter Korsgaard
1 sibling, 0 replies; 3+ messages in thread
From: Peter Korsgaard @ 2020-11-14 13:18 UTC (permalink / raw)
To: buildroot
>>>>> "Fabrice" == Fabrice Fontaine <fontaine.fabrice@gmail.com> writes:
> The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a
> large amount of memory.
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Committed, thanks.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037
2020-11-13 20:21 [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037 Fabrice Fontaine
2020-11-14 13:18 ` Peter Korsgaard
@ 2020-11-16 14:51 ` Peter Korsgaard
1 sibling, 0 replies; 3+ messages in thread
From: Peter Korsgaard @ 2020-11-16 14:51 UTC (permalink / raw)
To: buildroot
>>>>> "Fabrice" == Fabrice Fontaine <fontaine.fabrice@gmail.com> writes:
> The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a
> large amount of memory.
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Committed to 2020.02.x and 2020.08.x, thanks.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-11-13 20:21 [Buildroot] [PATCH 1/1] package/tcpdump: fix CVE-2020-8037 Fabrice Fontaine
2020-11-14 13:18 ` Peter Korsgaard
2020-11-16 14:51 ` Peter Korsgaard
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