busybox: CVE-2017-16544

In the add_match function in libbb/lineedit.c in BusyBox through 1.27.2,
the tab autocomplete feature of the shell, used to get a list of filenames
in a directory, does not sanitize filenames and results in executing any
escape sequence in the terminal. This could potentially result in code
execution, arbitrary file writes, or other attacks.

Backport the patch from:
https://git.busybox.net/busybox/commit/?id=c3797d40a1c57352192c6106cc0f435e7d9c11e8
https://nvd.nist.gov/vuln/detail/CVE-2017-16544

(From OE-Core rev: aa41f0c37460a2863ce26d1321c19c9bedf680c4)

Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/busybox/busybox/busybox-CVE-2017-16544.patch

@@ -0,0 +1,43 @@
+From c3797d40a1c57352192c6106cc0f435e7d9c11e8 Mon Sep 17 00:00:00 2001
+From: Denys Vlasenko <vda.linux@googlemail.com>
+Date: Tue, 7 Nov 2017 18:09:29 +0100
+Subject: lineedit: do not tab-complete any strings which have control
+ characters
+
+function                                             old     new   delta
+add_match                                             41      68     +27
+
+CVE: CVE-2017-16544
+Upstream-Status: Backport
+
+Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
+Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>
+---
+ libbb/lineedit.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/libbb/lineedit.c b/libbb/lineedit.c
+index c0e35bb..56e8140 100644
+--- a/libbb/lineedit.c
++++ b/libbb/lineedit.c
+@@ -645,6 +645,18 @@ static void free_tab_completion_data(void)
+ 
+ static void add_match(char *matched)
+ {
++	unsigned char *p = (unsigned char*)matched;
++	while (*p) {
++		/* ESC attack fix: drop any string with control chars */
++		if (*p < ' '
++		 || (!ENABLE_UNICODE_SUPPORT && *p >= 0x7f)
++		 || (ENABLE_UNICODE_SUPPORT && *p == 0x7f)
++		) {
++			free(matched);
++			return;
++		}
++		p++;
++	}
+ 	matches = xrealloc_vector(matches, 4, num_matches);
+ 	matches[num_matches] = matched;
+ 	num_matches++;
+-- 
+cgit v0.12

meta/recipes-core/busybox/busybox_1.27.2.bb

@@ -43,6 +43,7 @@ SRC_URI = "http://www.busybox.net/downloads/busybox-${PV}.tar.bz2;name=tarball \
            file://runlevel \
            file://makefile-libbb-race.patch \
            file://CVE-2011-5325.patch \
+           file://busybox-CVE-2017-16544.patch \
 "
 SRC_URI_append_libc-musl = " file://musl.cfg "