Use getpwuid_r() instead of getpwuid()
In the Netopeer2 test suite, two threads were calling getpwuid(), which
is not a reentrant function. Here's a trace from TSAN:
WARNING: ThreadSanitizer: data race (pid=3803971)
Write of size 8 at 0x7fc95e073f40 by thread T2:
#0 getpwuid <null> (test_parallel_sessions+0x4367d4)
#1 nc_connect_unix libnetconf2/src/session_client.c:1270:10 (libnetconf2.so.2+0x1ba34)
#2 send_get_rpc Netopeer2/tests/test_parallel_sessions.c:68:15 (test_parallel_sessions+0x4ea807)
Previous write of size 8 at 0x7fc95e073f40 by thread T1:
#0 getpwuid <null> (test_parallel_sessions+0x4367d4)
#1 nc_connect_unix libnetconf2/src/session_client.c:1270:10 (libnetconf2.so.2+0x1ba34)
#2 send_get_rpc Netopeer2/tests/test_parallel_sessions.c:68:15 (test_parallel_sessions+0x4ea807)
Location is global 'resbuf.11357' of size 48 at 0x7fc95e073f40 (libc.so.6+0x1bcf40)
Thread T2 (tid=3807449, running) created by main thread at:
#0 pthread_create <null> (test_parallel_sessions+0x469032)
#1 test_first Netopeer2/tests/test_parallel_sessions.c:115:9 (test_parallel_sessions+0x4ea6c2)
#2 cmocka_run_one_test_or_fixture <null> (libcmocka.so.0+0x630e)
Thread T1 (tid=3807448, running) created by main thread at:
#0 pthread_create <null> (test_parallel_sessions+0x469032)
#1 test_first Netopeer2/tests/test_parallel_sessions.c:115:9 (test_parallel_sessions+0x4ea6ad)
#2 cmocka_run_one_test_or_fixture <null> (libcmocka.so.0+0x630e)
SUMMARY: ThreadSanitizer: data race (Netopeer2/tests/test_parallel_sessions+0x4367d4) in __interceptor_getpwuid
Fix that by switching to getpwuid_r(). The code is very similar to the
auth_password_getpwnam() wrapper from session_server_ssh.c. I chose to
put this into io.c even though it is not really an IO function, but the
existing nc_realloc() is in that file as well.
diff --git a/src/io.c b/src/io.c
index 97ad40a..7048430 100644
--- a/src/io.c
+++ b/src/io.c
@@ -17,10 +17,12 @@
#include <errno.h>
#include <inttypes.h>
#include <poll.h>
+#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/types.h>
#include <time.h>
#include <unistd.h>
@@ -1158,3 +1160,39 @@
return ret;
}
+
+struct passwd *
+nc_getpwuid(uid_t uid, struct passwd *pwd_buf, char **buf, size_t *buf_size)
+{
+ struct passwd *pwd = NULL;
+ char *mem;
+ int r = 0;
+
+ do {
+ r = getpwuid_r(uid, pwd_buf, *buf, *buf_size, &pwd);
+ if (pwd) {
+ break;
+ }
+
+ if (r == ERANGE) {
+ if (!*buf_size) {
+ ssize_t size = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (size == -1) {
+ *buf_size = 256;
+ } else {
+ *buf_size = size;
+ }
+ } else {
+ *buf_size <<= 2;
+ }
+ mem = realloc(*buf, *buf_size);
+ if (!mem) {
+ ERRMEM;
+ return NULL;
+ }
+ *buf = mem;
+ }
+ } while (r == ERANGE);
+
+ return pwd;
+}
diff --git a/src/session_client.c b/src/session_client.c
index b2a1854..7640856 100644
--- a/src/session_client.c
+++ b/src/session_client.c
@@ -1238,16 +1238,18 @@
{
struct nc_session *session = NULL;
struct sockaddr_un sun;
- const struct passwd *pw;
+ struct passwd *pw, pw_buf;
char *username;
int sock = -1;
+ char *buf = NULL;
+ size_t buf_size = 0;
if (address == NULL) {
ERRARG("address");
return NULL;
}
- pw = getpwuid(geteuid());
+ pw = nc_getpwuid(geteuid(), &pw_buf, &buf, &buf_size);
if (pw == NULL) {
ERR(NULL, "Failed to find username for euid=%u.\n", geteuid());
goto fail;
diff --git a/src/session_client_ssh.c b/src/session_client_ssh.c
index bb95064..7533285 100644
--- a/src/session_client_ssh.c
+++ b/src/session_client_ssh.c
@@ -1545,8 +1545,10 @@
char *host = NULL, *username = NULL, *ip_host;
unsigned int port = 0;
int sock;
- struct passwd *pw;
+ struct passwd *pw, pw_buf;
struct nc_session *session = NULL;
+ char *buf;
+ size_t buf_len;
if (!ssh_session) {
ERRARG("ssh_session");
@@ -1604,7 +1606,7 @@
/* remember username */
if (!username) {
if (!opts->username) {
- pw = getpwuid(getuid());
+ pw = nc_getpwuid(getuid(), &pw_buf, &buf, &buf_len);
if (!pw) {
ERR(NULL, "Unknown username for the SSH connection (%s).", strerror(errno));
goto fail;
@@ -1683,8 +1685,10 @@
int sock;
uint32_t port_uint;
char *username, *ip_host = NULL;
- struct passwd *pw;
+ struct passwd *pw, pw_buf;
struct nc_session *session = NULL;
+ char *buf = NULL;
+ size_t buf_len = 0;
/* process parameters */
if (!host || strisempty(host)) {
@@ -1697,7 +1701,7 @@
port_uint = port;
if (!ssh_opts.username) {
- pw = getpwuid(getuid());
+ pw = nc_getpwuid(getuid(), &pw_buf, &buf, &buf_len);
if (!pw) {
ERR(session, "Unknown username for the SSH connection (%s).", strerror(errno));
return NULL;
@@ -1855,9 +1859,11 @@
{
const long ssh_timeout = NC_SSH_TIMEOUT;
unsigned int uint_port;
- struct passwd *pw;
+ struct passwd *pw, pw_buf;
struct nc_session *session;
ssh_session sess;
+ char *buf = NULL;
+ size_t buf_len = 0;
sess = ssh_new();
if (!sess) {
@@ -1873,7 +1879,7 @@
ssh_options_set(sess, SSH_OPTIONS_PORT, &uint_port);
ssh_options_set(sess, SSH_OPTIONS_TIMEOUT, &ssh_timeout);
if (!ssh_ch_opts.username) {
- pw = getpwuid(getuid());
+ pw = nc_getpwuid(getuid(), &pw_buf, &buf, &buf_len);
if (!pw) {
ERR(NULL, "Unknown username for the SSH connection (%s).", strerror(errno));
ssh_free(sess);
diff --git a/src/session_p.h b/src/session_p.h
index a219caa..f467bb3 100644
--- a/src/session_p.h
+++ b/src/session_p.h
@@ -514,6 +514,8 @@
void *nc_realloc(void *ptr, size_t size);
+struct passwd *nc_getpwuid(uid_t uid, struct passwd *pwd_buf, char **buf, size_t *buf_size);
+
NC_MSG_TYPE nc_send_msg_io(struct nc_session *session, int io_timeout, struct lyd_node *op);
int nc_gettimespec_mono(struct timespec *ts);
diff --git a/src/session_server.c b/src/session_server.c
index 19fc1cc..4e90d25 100644
--- a/src/session_server.c
+++ b/src/session_server.c
@@ -1877,17 +1877,19 @@
nc_accept_unix(struct nc_session *session, int sock)
{
#if defined (SO_PEERCRED) || defined (HAVE_GETPEEREID)
- const struct passwd *pw;
+ struct passwd *pw, pw_buf;
char *username;
session->ti_type = NC_TI_UNIX;
uid_t uid = 0;
+ char *buf = NULL;
+ size_t buf_len = 0;
if (nc_get_uid(sock, &uid)) {
close(sock);
return -1;
}
- pw = getpwuid(uid);
+ pw = nc_getpwuid(uid, &pw_buf, &buf, &buf_len);
if (pw == NULL) {
ERR(NULL, "Failed to find username for uid=%u (%s).\n", uid, strerror(errno));
close(sock);