inetutils: CVE-2022-39028 - fix remote DoS vulnerability in inetutils-telnetd

Fix telnetd crash if the first two bytes of a new connection
are 0xff 0xf7 (IAC EC) or 0xff 0xf8 (IAC EL).

CVE: CVE-2022-39028

(From OE-Core rev: 1c385e70d4bfab2334361ba82f29988bb11d6902)

Signed-off-by:Minjae Kim <flowergom@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 55 insertions, 0 deletions

diff --git a/meta/recipes-connectivity/inetutils/inetutils/CVE-2022-39028.patch b/meta/recipes-connectivity/inetutils/inetutils/CVE-2022-39028.patch
new file mode 100644
index 0000000000..da2da8da8a
--- /dev/null
+++ b/meta/recipes-connectivity/inetutils/inetutils/CVE-2022-39028.patch
@@ -0,0 +1,54 @@
+From eaae65aac967f9628787dca4a2501ca860bb6598 Mon Sep 17 00:00:00 2001
+From: Minjae Kim <flowergom@gmail.com>
+Date: Mon, 26 Sep 2022 22:05:07 +0200
+Subject: [PATCH] telnetd: Handle early IAC EC or IAC EL receipt
+
+Fix telnetd crash if the first two bytes of a new connection
+are 0xff 0xf7 (IAC EC) or 0xff 0xf8 (IAC EL).
+
+The problem was reported in:
+<https://pierrekim.github.io/blog/2022-08-24-2-byte-dos-freebsd-netbsd-telnetd-netkit-telnetd-inetutils-telnetd-kerberos-telnetd.html>.
+
+* NEWS: Mention fix.
+* telnetd/state.c (telrcv): Handle zero slctab[SLC_EC].sptr and
+zero slctab[SLC_EL].sptr.
+
+CVE: CVE-2022-39028
+Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/inetutils.git/commit/?id=fae8263e467380483c28513c0e5fac143e46f94f]
+Signed-off-by: Minjae Kim<flowergom@gmail.com>
+---
+ telnetd/state.c | 12 +++++++++---
+ 1 file changed, 9 insertions(+), 3 deletions(-)
+
+diff --git a/telnetd/state.c b/telnetd/state.c
+index 2184bca..7948503 100644
+--- a/telnetd/state.c
++++ b/telnetd/state.c
+@@ -314,15 +314,21 @@ telrcv (void)
+            case EC:
+            case EL:
+              {
+-               cc_t ch;
++               cc_t ch = (cc_t) (_POSIX_VDISABLE);
+ 
+                DEBUG (debug_options, 1, printoption ("td: recv IAC", c));
+                ptyflush ();    /* half-hearted */
+                init_termbuf ();
+                if (c == EC)
+-                 ch = *slctab[SLC_EC].sptr;
++               {
++                 if (slctab[SLC_EC].sptr)
++                   ch = *slctab[SLC_EC].sptr;
++               }
+                else
+-                 ch = *slctab[SLC_EL].sptr;
++               {
++                 if (slctab[SLC_EL].sptr)
++                   ch = *slctab[SLC_EL].sptr;
++               }
+                if (ch != (cc_t) (_POSIX_VDISABLE))
+                  pty_output_byte ((unsigned char) ch);
+                break;
+-- 
+2.25.1
+
diff --git a/meta/recipes-connectivity/inetutils/inetutils_1.9.4.bb b/meta/recipes-connectivity/inetutils/inetutils_1.9.4.bb
index f4450e19f4..fe391b8bce 100644
--- a/meta/recipes-connectivity/inetutils/inetutils_1.9.4.bb
+++ b/meta/recipes-connectivity/inetutils/inetutils_1.9.4.bb
@@ -24,6 +24,7 @@ SRC_URI = "${GNU_MIRROR}/inetutils/inetutils-${PV}.tar.gz \
            file://0001-rcp-fix-to-work-with-large-files.patch \
            file://fix-buffer-fortify-tfpt.patch \
            file://CVE-2021-40491.patch \
+           file://CVE-2022-39028.patch \
 "
 
 SRC_URI[md5sum] = "04852c26c47cc8c6b825f2b74f191f52"