From 650d5c39753d095f8ae6cff418306cf1a6b8fd25 Mon Sep 17 00:00:00 2001
From: Jan Synacek <jsynacek@redhat.com>
Date: Fri, 2 Nov 2018 08:40:40 +0100
Subject: [PATCH] =?UTF-8?q?core:=20when=20deserializing=20state=20always?=
=?UTF-8?q?=20use=20read=5Fline(=E2=80=A6,=20LONG=5FLINE=5FMAX,=20?=
=?UTF-8?q?=E2=80=A6)?=
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This should be much better than fgets(), as we can read substantially
longer lines and overly long lines result in proper errors.
Fixes a vulnerability discovered by Jann Horn at Google.
(cherry picked from commit 8948b3415d762245ebf5e19d80b97d4d8cc208c1)
Resolves: CVE-2018-15686
[jsynacek] There were more commits in the pull request of which the cherry
picked commit was a part of, see
https://github.com/systemd/systemd/pull/10519/commits.
I decided not to backport any of the remaining ones, because they were
mostly irrelevant to the actual fix.
---
src/core/job.c | 19 +++++++++++--------
src/core/manager.c | 38 ++++++++++++++++----------------------
src/core/unit.c | 17 ++++++++---------
3 files changed, 35 insertions(+), 39 deletions(-)
diff --git a/src/core/job.c b/src/core/job.c
index 275503169b..998b231ed9 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -38,6 +38,7 @@
#include "async.h"
#include "virt.h"
#include "dbus.h"
+#include "fileio.h"
Job* job_new_raw(Unit *unit) {
Job *j;
@@ -1035,23 +1036,25 @@ int job_serialize(Job *j, FILE *f, FDSet *fds) {
}
int job_deserialize(Job *j, FILE *f, FDSet *fds) {
+ int r = 0;
+
assert(j);
for (;;) {
- char line[LINE_MAX], *l, *v;
+ _cleanup_free_ char *line = NULL;
+ char *l, *v;
size_t k;
- if (!fgets(line, sizeof(line), f)) {
- if (feof(f))
- return 0;
- return -errno;
- }
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_error_errno(r, "Failed to read serialization line: %m");
+ if (r == 0)
+ return 0;
- char_array_0(line);
l = strstrip(line);
/* End marker */
- if (l[0] == 0)
+ if (isempty(l))
return 0;
k = strcspn(l, "=");
diff --git a/src/core/manager.c b/src/core/manager.c
index 0466e4bb8a..73d6c81fdb 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -37,6 +37,7 @@
#include <sys/stat.h>
#include <dirent.h>
#include <sys/timerfd.h>
+#include <fileio.h>
#ifdef HAVE_AUDIT
#include <libaudit.h>
@@ -2559,21 +2560,19 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
m->n_reloading ++;
for (;;) {
- char line[LINE_MAX], *l;
+ _cleanup_free_ char *line = NULL;
+ char *l;
- if (!fgets(line, sizeof(line), f)) {
- if (feof(f))
- r = 0;
- else
- r = -errno;
- goto finish;
- }
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_error_errno(r, "Failed to read serialization line: %m");
+ if (r == 0)
+ break;
- char_array_0(line);
l = strstrip(line);
- if (l[0] == 0)
+ if (isempty(l)) /* end marker */
break;
if (startswith(l, "current-job-id=")) {
@@ -2708,22 +2707,17 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
}
for (;;) {
+ _cleanup_free_ char *line = NULL;
Unit *u;
- char name[UNIT_NAME_MAX+2];
/* Start marker */
- if (!fgets(name, sizeof(name), f)) {
- if (feof(f))
- r = 0;
- else
- r = -errno;
-
- goto finish;
- }
-
- char_array_0(name);
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_error_errno(r, "Failed to read serialization line: %m");
+ if (r == 0)
+ break;
- r = manager_load_unit(m, strstrip(name), NULL, NULL, &u);
+ r = manager_load_unit(m, strstrip(line), NULL, NULL, &u);
if (r < 0)
goto finish;
diff --git a/src/core/unit.c b/src/core/unit.c
index e8532a057d..37fac8db3a 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2644,20 +2644,19 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
rt = (ExecRuntime**) ((uint8_t*) u + offset);
for (;;) {
- char line[LINE_MAX], *l, *v;
+ _cleanup_free_ char *line = NULL;
+ char *l, *v;
size_t k;
- if (!fgets(line, sizeof(line), f)) {
- if (feof(f))
- return 0;
- return -errno;
- }
+ r = read_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return log_error_errno(r, "Failed to read serialization line: %m");
+ if (r == 0) /* eof */
+ return 0;
- char_array_0(line);
l = strstrip(line);
-
/* End marker */
- if (l[0] == 0)
+ if (isempty(l))
return 0;
k = strcspn(l, "=");