Fix line_begins() to accept word matching full string (#1631840)

Resolves: #1631840

0003-bus-socket-Fix-line_begins-to-accept-word-matching-f.patch

@@ -0,0 +1,48 @@
+From 3f10c66270b74530339b3f466c43874bb40c210f Mon Sep 17 00:00:00 2001
+From: Filipe Brandenburger <filbranden@google.com>
+Date: Tue, 17 Jul 2018 11:32:40 -0700
+Subject: [PATCH] bus-socket: Fix line_begins() to accept word matching full
+ string
+
+The switch to memory_startswith() changed the logic to only look for a space or
+NUL byte after the matched word, but matching the full size should also be
+acceptable.
+
+This changed the behavior of parsing of "AUTH\r\n", where m will be set to 4,
+since even though the word will match, the check for it being followed by ' '
+or NUL will make line_begins() return false.
+
+Tested:
+
+- Using netcat to connect to the private socket directly:
+  $ echo -ne '\0AUTH\r\n' | sudo nc -U /run/systemd/private
+  REJECTED EXTERNAL ANONYMOUS
+
+- Running the Ignition blackbox test:
+  $ sudo sh -c 'PATH=$PWD/bin/amd64:$PATH ./tests.test'
+  PASS
+
+Fixes: d27b725abf64a19a6b2f99332b663f17ad046771
+---
+ src/libsystemd/sd-bus/bus-socket.c | 5 +----
+ 1 file changed, 1 insertion(+), 4 deletions(-)
+
+diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
+index be491c957..a785a247c 100644
+--- a/src/libsystemd/sd-bus/bus-socket.c
++++ b/src/libsystemd/sd-bus/bus-socket.c
+@@ -246,10 +246,7 @@ static bool line_begins(const char *s, size_t m, const char *word) {
+         const char *p;
+ 
+         p = memory_startswith(s, m, word);
+-        if (!p)
+-                return false;
+-
+-        return IN_SET(*p, 0, ' ');
++        return p && (p == (s + m) || *p == ' ');
+ }
+ 
+ static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
+-- 
+2.14.4
+

systemd.spec

@@ -52,6 +52,7 @@ GIT_DIR=../../src/systemd/.git git diffab -M v233..master@{2017-06-15} -- hwdb/[
 
 Patch0001:      0001-build-sys-Detect-whether-struct-statx-is-defined-in-.patch
 Patch0002:      0002-meson-rename-Ddebug-to-Ddebug-extra.patch
+Patch0003:      0003-bus-socket-Fix-line_begins-to-accept-word-matching-f.patch
 
 Patch0998:      0998-resolved-create-etc-resolv.conf-symlink-at-runtime.patch
 
@@ -694,6 +695,7 @@ fi
 %changelog
 * Wed Oct  3 2018 Jan Synáček <jsynacek@redhat.com> - 239-5
 - Fix meson using -Ddebug, which results in FTBFS
+- Fix line_begins() to accept word matching full string (#1631840)
 
 * Mon Sep 10 2018 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 239-4
 - Move /etc/yum/protected.d/systemd.conf to /etc/dnf/ (#1626969)