From 55a1c766445750aaefe28bd7bea454f5f1cff9bb Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 17 Oct 2018 18:36:24 +0200
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.
CVE-2018-15686
LP: #1796402
https://bugzilla.redhat.com/show_bug.cgi?id=1639071
(cherry picked from commit 8948b3415d762245ebf5e19d80b97d4d8cc208c1)
Resolves: CVE-2018-15686
---
src/core/job.c | 19 +++++++++++--------
src/core/manager.c | 47 ++++++++++++++++++++--------------------------
src/core/unit.c | 34 +++++++++++++++++----------------
src/core/unit.h | 2 +-
4 files changed, 50 insertions(+), 52 deletions(-)
diff --git a/src/core/job.c b/src/core/job.c
index 734756b666..8552ffb704 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -10,6 +10,7 @@
#include "dbus-job.h"
#include "dbus.h"
#include "escape.h"
+#include "fileio.h"
#include "job.h"
#include "log.h"
#include "macro.h"
@@ -1091,24 +1092,26 @@ int job_serialize(Job *j, FILE *f) {
}
int job_deserialize(Job *j, FILE *f) {
+ int r;
+
assert(j);
assert(f);
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 3b2fe11e87..c83e296cf3 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -3144,22 +3144,17 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
m->n_reloading++;
for (;;) {
- char line[LINE_MAX];
+ _cleanup_free_ char *line = NULL;
const char *val, *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 ((val = startswith(l, "current-job-id="))) {
@@ -3326,29 +3321,27 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
}
for (;;) {
- Unit *u;
- char name[UNIT_NAME_MAX+2];
+ _cleanup_free_ char *line = NULL;
const char* unit_name;
+ Unit *u;
/* Start marker */
- if (!fgets(name, sizeof(name), 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(name);
- unit_name = strstrip(name);
+ unit_name = strstrip(line);
r = manager_load_unit(m, unit_name, NULL, NULL, &u);
if (r < 0) {
log_notice_errno(r, "Failed to load unit \"%s\", skipping deserialization: %m", unit_name);
- if (r == -ENOMEM)
- goto finish;
- unit_deserialize_skip(f);
+
+ r = unit_deserialize_skip(f);
+ if (r < 0)
+ return r;
+
continue;
}
diff --git a/src/core/unit.c b/src/core/unit.c
index 721d8d60a3..cc43ddc4f1 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -3368,21 +3368,19 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
assert(fds);
for (;;) {
- char line[LINE_MAX], *l, *v;
+ _cleanup_free_ char *line = NULL;
CGroupIPAccountingMetric m;
+ 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 */
+ break;
- char_array_0(line);
l = strstrip(line);
-
- /* End marker */
- if (isempty(l))
+ if (isempty(l)) /* End marker */
break;
k = strcspn(l, "=");
@@ -3657,23 +3655,27 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
return 0;
}
-void unit_deserialize_skip(FILE *f) {
+int unit_deserialize_skip(FILE *f) {
+ int r;
assert(f);
/* Skip serialized data for this unit. We don't know what it is. */
for (;;) {
- char line[LINE_MAX], *l;
+ _cleanup_free_ char *line = NULL;
+ char *l;
- if (!fgets(line, sizeof line, f))
- return;
+ 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 (isempty(l))
- return;
+ return 1;
}
}
diff --git a/src/core/unit.h b/src/core/unit.h
index b3131eba1b..e1a60da244 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -679,7 +679,7 @@ bool unit_can_serialize(Unit *u) _pure_;
int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs);
int unit_deserialize(Unit *u, FILE *f, FDSet *fds);
-void unit_deserialize_skip(FILE *f);
+int unit_deserialize_skip(FILE *f);
int unit_serialize_item(Unit *u, FILE *f, const char *key, const char *value);
int unit_serialize_item_escaped(Unit *u, FILE *f, const char *key, const char *value);