diff --git a/keepalived/core/pidfile.c b/keepalived/core/pidfile.c
index f3f3a2c8..6cfbfe8d 100644
--- a/keepalived/core/pidfile.c
+++ b/keepalived/core/pidfile.c
@@ -54,7 +54,7 @@ int
pidfile_write(const char *pid_file, int pid)
{
FILE *pidfile = NULL;
- int pidfd = creat(pid_file, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+ int pidfd = open(pid_file, O_NOFOLLOW | O_CREAT | O_WRONLY | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (pidfd != -1) pidfile = fdopen(pidfd, "w");
if (!pidfile) {
diff --git a/keepalived/vrrp/vrrp_dbus.c b/keepalived/vrrp/vrrp_dbus.c
index f29a974f..1320a6c2 100644
--- a/keepalived/vrrp/vrrp_dbus.c
+++ b/keepalived/vrrp/vrrp_dbus.c
@@ -551,7 +551,7 @@ read_file(gchar* filepath)
size_t length;
gchar *ret = NULL;
- f = fopen(filepath, "rb");
+ f = fopen(filepath, "r");
if (f) {
fseek(f, 0, SEEK_END);
length = (size_t)ftell(f);
diff --git a/keepalived/vrrp/vrrp_print.c b/keepalived/vrrp/vrrp_print.c
index 7adb701d..03840adf 100644
--- a/keepalived/vrrp/vrrp_print.c
+++ b/keepalived/vrrp/vrrp_print.c
@@ -27,6 +27,7 @@
#include "vrrp.h"
#include "vrrp_data.h"
#include "vrrp_print.h"
+#include "utils.h"
#ifdef _HAVE_FIB_ROUTING_
#include "vrrp_iproute.h"
#include "vrrp_iprule.h"
@@ -350,7 +351,7 @@ void
vrrp_print_data(void)
{
FILE *file;
- file = fopen ("/tmp/keepalived.data","w");
+ file = fopen_safe("/tmp/keepalived.data","w");
if (!file) {
log_message(LOG_INFO, "Can't open /tmp/keepalived.data (%d: %s)",
@@ -374,7 +375,7 @@ void
vrrp_print_stats(void)
{
FILE *file;
- file = fopen ("/tmp/keepalived.stats","w");
+ file = fopen_safe("/tmp/keepalived.stats","w");
if (!file) {
log_message(LOG_INFO, "Can't open /tmp/keepalived.stats (%d: %s)",
@@ -393,8 +394,7 @@ vrrp_print_stats(void)
fprintf(file, " Received: %" PRIu64 "\n", vrrp->stats->advert_rcvd);
fprintf(file, " Sent: %d\n", vrrp->stats->advert_sent);
fprintf(file, " Became master: %d\n", vrrp->stats->become_master);
- fprintf(file, " Released master: %d\n",
- vrrp->stats->release_master);
+ fprintf(file, " Released master: %d\n", vrrp->stats->release_master);
fprintf(file, " Packet Errors:\n");
fprintf(file, " Length: %" PRIu64 "\n", vrrp->stats->packet_len_err);
fprintf(file, " TTL: %" PRIu64 "\n", vrrp->stats->ip_ttl_err);
diff --git a/lib/memory.c b/lib/memory.c
index 96a4e7b9..04b3d6ee 100644
--- a/lib/memory.c
+++ b/lib/memory.c
@@ -441,7 +441,7 @@ mem_log_init(const char* prog_name, const char *banner)
}
snprintf(log_name, log_name_len, "/tmp/%s_mem.%d.log", prog_name, getpid());
- log_op = fopen(log_name, "a");
+ log_op = fopen_safe(log_name, "a");
if (log_op == NULL) {
log_message(LOG_INFO, "Unable to open %s for appending", log_name);
log_op = stderr;
diff --git a/lib/parser.c b/lib/parser.c
index 2f7959e8..a5c3465b 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -153,12 +153,12 @@ dump_keywords(vector_t *keydump, int level, FILE *fp)
{
unsigned int i;
keyword_t *keyword_vec;
- char file_name[21];
+ char file_name[22];
if (!level) {
sprintf(file_name, "/tmp/keywords.%d", getpid());
snprintf(file_name, sizeof(file_name), "/tmp/keywords.%d", getpid());
- fp = fopen(file_name, "w");
+ fp = fopen_safe(file_name, "w");
if (!fp)
return;
}
diff --git a/lib/utils.c b/lib/utils.c
index 88465609..f317937e 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -89,7 +89,7 @@ dump_buffer(char *buff, size_t count, FILE* fp)
void
write_stacktrace(const char *file_name)
{
- int fd = open(file_name, O_WRONLY | O_APPEND | O_CREAT, 0644);
+ int fd = open(file_name, O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
void *buffer[100];
int nptrs;
@@ -518,6 +518,47 @@ string_equal(const char *str1, const char *str2)
return (*str1 == 0 && *str2 == 0);
}
+/* We need to use O_NOFOLLOW if opening a file for write, so that a non privileged user can't
+ * create a symbolic link from the path to a system file and cause a system file to be overwritten. */
+FILE *fopen_safe(const char *path, const char *mode)
+{
+ int fd;
+ FILE *file;
+ int flags = O_NOFOLLOW | O_CREAT;
+
+ if (mode[0] == 'r')
+ return fopen(path, mode);
+
+ if (mode[0] != 'a' && mode[0] != 'w')
+ return NULL;
+
+ if (mode[1] &&
+ (mode[1] != '+' || mode[2]))
+ return NULL;
+
+ if (mode[0] == 'w')
+ flags |= O_TRUNC;
+ else
+ flags |= O_APPEND;
+
+ if (mode[1])
+ flags |= O_RDWR;
+ else
+ flags |= O_WRONLY;
+
+ fd = open(path, flags, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
+ if (fd == -1)
+ return NULL;
+
+ file = fdopen (fd, "w");
+ if (!file) {
+ close(fd);
+ return NULL;
+ }
+
+ return file;
+}
+
void
set_std_fd(int force)
{
diff --git a/lib/utils.h b/lib/utils.h
index ec717125..1e440795 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -70,6 +70,7 @@ extern int inet_inaddrcmp(int, void *, void *);
extern int inet_sockaddrcmp(struct sockaddr_storage *, struct sockaddr_storage *);
extern char *get_local_name(void);
extern int string_equal(const char *, const char *);
+extern FILE *fopen_safe(const char *, const char *);
extern void set_std_fd(int);
#if !defined _HAVE_LIBIPTC_ || defined _LIBIPTC_DYNAMIC_
extern int fork_exec(char **argv);