From 8ccebb04e07628f7fe10131d6cd4f19d6a0d8f45 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 8 Aug 2018 15:06:36 +0900
Subject: [PATCH] journal: fix syslog_parse_identifier()

Fixes #9829.

An out of bounds read was discovered in systemd-journald in the way it
parses log messages that terminate with a colon ':'. A local attacker
can use this flaw to disclose process memory data.

Patch backported from systemd master at
a6aadf4ae0bae185dc4c414d492a4a781c80ffe5.

This matches the change done for systemd-journald, hence forming the first
part of the fix for CVE-2018-16866.
---
 src/journal/journald-syslog.c     |  6 +++---
 src/journal/test-journal-syslog.c | 10 ++++++++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/journal/journald-syslog.c b/src/journal/journald-syslog.c
index 9dea116722..97711ac7a3 100644
--- a/src/journal/journald-syslog.c
+++ b/src/journal/journald-syslog.c
@@ -194,7 +194,7 @@ size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid)
         e = l;
         l--;
 
-        if (p[l-1] == ']') {
+        if (l > 0 && p[l-1] == ']') {
                 size_t k = l-1;
 
                 for (;;) {
@@ -219,8 +219,8 @@ size_t syslog_parse_identifier(const char **buf, char **identifier, char **pid)
         if (t)
                 *identifier = t;
 
-        if (strchr(WHITESPACE, p[e]))
-                e++;
+        e += strspn(p + e, WHITESPACE);
+
         *buf = p + e;
         return e;
 }
diff --git a/src/journal/test-journal-syslog.c b/src/journal/test-journal-syslog.c
index 9ba86f6c8a..05f759817e 100644
--- a/src/journal/test-journal-syslog.c
+++ b/src/journal/test-journal-syslog.c
@@ -5,8 +5,8 @@
 #include "macro.h"
 #include "string-util.h"
 
-static void test_syslog_parse_identifier(const char* str,
-                                         const char *ident, const char*pid, int ret) {
+static void test_syslog_parse_identifier(const char *str,
+                                         const char *ident, const char *pid, int ret) {
         const char *buf = str;
         _cleanup_free_ char *ident2 = NULL, *pid2 = NULL;
         int ret2;
@@ -21,7 +21,13 @@ static void test_syslog_parse_identifier(const char* str,
 int main(void) {
         test_syslog_parse_identifier("pidu[111]: xxx", "pidu", "111", 11);
         test_syslog_parse_identifier("pidu: xxx", "pidu", NULL, 6);
+        test_syslog_parse_identifier("pidu:  xxx", "pidu", NULL, 7);
         test_syslog_parse_identifier("pidu xxx", NULL, NULL, 0);
+        test_syslog_parse_identifier(":", "", NULL, 1);
+        test_syslog_parse_identifier(":  ", "", NULL, 3);
+        test_syslog_parse_identifier("pidu:", "pidu", NULL, 5);
+        test_syslog_parse_identifier("pidu: ", "pidu", NULL, 6);
+        test_syslog_parse_identifier("pidu : ", NULL, NULL, 0);
 
         return 0;
 }
-- 
2.11.0