1
0
mirror of https://github.com/samba-team/samba.git synced 2024-12-24 21:34:56 +03:00
samba-mirror/nsswitch/wb_common.c
Volker Lendecke c6909887c2 nsswitch: Fix short writes in winbind_write_sock
We set the socket to nonblocking and don't handle EAGAIN right. We do
a poll anyway, so wait for writability, which should fix this.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10195
Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
2013-10-21 17:52:35 +02:00

678 lines
14 KiB
C

/*
Unix SMB/CIFS implementation.
winbind client common code
Copyright (C) Tim Potter 2000
Copyright (C) Andrew Tridgell 2000
Copyright (C) Andrew Bartlett 2002
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define UID_WRAPPER_NOT_REPLACE
#include "replace.h"
#include "system/select.h"
#include "winbind_client.h"
/* Global variables. These are effectively the client state information */
int winbindd_fd = -1; /* fd for winbindd socket */
static int is_privileged = 0;
/* Free a response structure */
void winbindd_free_response(struct winbindd_response *response)
{
/* Free any allocated extra_data */
if (response)
SAFE_FREE(response->extra_data.data);
}
/* Initialise a request structure */
static void winbindd_init_request(struct winbindd_request *request,
int request_type)
{
request->length = sizeof(struct winbindd_request);
request->cmd = (enum winbindd_cmd)request_type;
request->pid = getpid();
}
/* Initialise a response structure */
static void init_response(struct winbindd_response *response)
{
/* Initialise return value */
response->result = WINBINDD_ERROR;
}
/* Close established socket */
#if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
__attribute__((destructor))
#endif
static void winbind_close_sock(void)
{
if (winbindd_fd != -1) {
close(winbindd_fd);
winbindd_fd = -1;
}
}
#define CONNECT_TIMEOUT 30
/* Make sure socket handle isn't stdin, stdout or stderr */
#define RECURSION_LIMIT 3
static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */)
{
int new_fd;
if (fd >= 0 && fd <= 2) {
#ifdef F_DUPFD
if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
return -1;
}
/* Paranoia */
if (new_fd < 3) {
close(new_fd);
return -1;
}
close(fd);
return new_fd;
#else
if (limit <= 0)
return -1;
new_fd = dup(fd);
if (new_fd == -1)
return -1;
/* use the program stack to hold our list of FDs to close */
new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
close(fd);
return new_fd;
#endif
}
return fd;
}
/****************************************************************************
Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
else
if SYSV use O_NDELAY
if BSD use FNDELAY
Set close on exec also.
****************************************************************************/
static int make_safe_fd(int fd)
{
int result, flags;
int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
if (new_fd == -1) {
close(fd);
return -1;
}
/* Socket should be nonblocking. */
#ifdef O_NONBLOCK
#define FLAG_TO_SET O_NONBLOCK
#else
#ifdef SYSV
#define FLAG_TO_SET O_NDELAY
#else /* BSD */
#define FLAG_TO_SET FNDELAY
#endif
#endif
if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
close(new_fd);
return -1;
}
flags |= FLAG_TO_SET;
if (fcntl(new_fd, F_SETFL, flags) == -1) {
close(new_fd);
return -1;
}
#undef FLAG_TO_SET
/* Socket should be closed on exec() */
#ifdef FD_CLOEXEC
result = flags = fcntl(new_fd, F_GETFD, 0);
if (flags >= 0) {
flags |= FD_CLOEXEC;
result = fcntl( new_fd, F_SETFD, flags );
}
if (result < 0) {
close(new_fd);
return -1;
}
#endif
return new_fd;
}
/* Connect to winbindd socket */
static int winbind_named_pipe_sock(const char *dir)
{
struct sockaddr_un sunaddr;
struct stat st;
char *path = NULL;
int fd;
int wait_time;
int slept;
/* Check permissions on unix socket directory */
if (lstat(dir, &st) == -1) {
errno = ENOENT;
return -1;
}
if (!S_ISDIR(st.st_mode) ||
(st.st_uid != 0 && st.st_uid != geteuid())) {
errno = ENOENT;
return -1;
}
/* Connect to socket */
if (asprintf(&path, "%s/%s", dir, WINBINDD_SOCKET_NAME) < 0) {
return -1;
}
ZERO_STRUCT(sunaddr);
sunaddr.sun_family = AF_UNIX;
strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
/* If socket file doesn't exist, don't bother trying to connect
with retry. This is an attempt to make the system usable when
the winbindd daemon is not running. */
if (lstat(path, &st) == -1) {
errno = ENOENT;
SAFE_FREE(path);
return -1;
}
SAFE_FREE(path);
/* Check permissions on unix socket file */
if (!S_ISSOCK(st.st_mode) ||
(st.st_uid != 0 && st.st_uid != geteuid())) {
errno = ENOENT;
return -1;
}
/* Connect to socket */
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
return -1;
}
/* Set socket non-blocking and close on exec. */
if ((fd = make_safe_fd( fd)) == -1) {
return fd;
}
for (wait_time = 0; connect(fd, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1;
wait_time += slept) {
struct pollfd pfd;
int ret;
int connect_errno = 0;
socklen_t errnosize;
if (wait_time >= CONNECT_TIMEOUT)
goto error_out;
switch (errno) {
case EINPROGRESS:
pfd.fd = fd;
pfd.events = POLLOUT;
ret = poll(&pfd, 1, (CONNECT_TIMEOUT - wait_time) * 1000);
if (ret > 0) {
errnosize = sizeof(connect_errno);
ret = getsockopt(fd, SOL_SOCKET,
SO_ERROR, &connect_errno, &errnosize);
if (ret >= 0 && connect_errno == 0) {
/* Connect succeed */
goto out;
}
}
slept = CONNECT_TIMEOUT;
break;
case EAGAIN:
slept = rand() % 3 + 1;
sleep(slept);
break;
default:
goto error_out;
}
}
out:
return fd;
error_out:
close(fd);
return -1;
}
static const char *winbindd_socket_dir(void)
{
#ifdef SOCKET_WRAPPER
const char *env_dir;
env_dir = getenv(WINBINDD_SOCKET_DIR_ENVVAR);
if (env_dir) {
return env_dir;
}
#endif
return WINBINDD_SOCKET_DIR;
}
/* Connect to winbindd socket */
static int winbind_open_pipe_sock(int recursing, int need_priv)
{
#ifdef HAVE_UNIXSOCKET
static pid_t our_pid;
struct winbindd_request request;
struct winbindd_response response;
ZERO_STRUCT(request);
ZERO_STRUCT(response);
if (our_pid != getpid()) {
winbind_close_sock();
our_pid = getpid();
}
if ((need_priv != 0) && (is_privileged == 0)) {
winbind_close_sock();
}
if (winbindd_fd != -1) {
return winbindd_fd;
}
if (recursing) {
return -1;
}
if ((winbindd_fd = winbind_named_pipe_sock(winbindd_socket_dir())) == -1) {
return -1;
}
is_privileged = 0;
/* version-check the socket */
request.wb_flags = WBFLAG_RECURSE;
if ((winbindd_request_response(WINBINDD_INTERFACE_VERSION, &request, &response) != NSS_STATUS_SUCCESS) || (response.data.interface_version != WINBIND_INTERFACE_VERSION)) {
winbind_close_sock();
return -1;
}
/* try and get priv pipe */
request.wb_flags = WBFLAG_RECURSE;
if (winbindd_request_response(WINBINDD_PRIV_PIPE_DIR, &request, &response) == NSS_STATUS_SUCCESS) {
int fd;
if ((fd = winbind_named_pipe_sock((char *)response.extra_data.data)) != -1) {
close(winbindd_fd);
winbindd_fd = fd;
is_privileged = 1;
}
}
if ((need_priv != 0) && (is_privileged == 0)) {
return -1;
}
SAFE_FREE(response.extra_data.data);
return winbindd_fd;
#else
return -1;
#endif /* HAVE_UNIXSOCKET */
}
/* Write data to winbindd socket */
static int winbind_write_sock(void *buffer, int count, int recursing,
int need_priv)
{
int fd, result, nwritten;
/* Open connection to winbind daemon */
restart:
fd = winbind_open_pipe_sock(recursing, need_priv);
if (fd == -1) {
errno = ENOENT;
return -1;
}
/* Write data to socket */
nwritten = 0;
while(nwritten < count) {
struct pollfd pfd;
int ret;
/* Catch pipe close on other end by checking if a read()
call would not block by calling poll(). */
pfd.fd = fd;
pfd.events = POLLIN|POLLOUT|POLLHUP;
ret = poll(&pfd, 1, -1);
if (ret == -1) {
winbind_close_sock();
return -1; /* poll error */
}
/* Write should be OK if fd not available for reading */
if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
/* Pipe has closed on remote end */
winbind_close_sock();
goto restart;
}
/* Do the write */
result = write(fd, (char *)buffer + nwritten,
count - nwritten);
if ((result == -1) || (result == 0)) {
/* Write failed */
winbind_close_sock();
return -1;
}
nwritten += result;
}
return nwritten;
}
/* Read data from winbindd socket */
static int winbind_read_sock(void *buffer, int count)
{
int fd;
int nread = 0;
int total_time = 0;
fd = winbind_open_pipe_sock(false, false);
if (fd == -1) {
return -1;
}
/* Read data from socket */
while(nread < count) {
struct pollfd pfd;
int ret;
/* Catch pipe close on other end by checking if a read()
call would not block by calling poll(). */
pfd.fd = fd;
pfd.events = POLLIN|POLLHUP;
/* Wait for 5 seconds for a reply. May need to parameterise this... */
ret = poll(&pfd, 1, 5000);
if (ret == -1) {
winbind_close_sock();
return -1; /* poll error */
}
if (ret == 0) {
/* Not ready for read yet... */
if (total_time >= 30) {
/* Timeout */
winbind_close_sock();
return -1;
}
total_time += 5;
continue;
}
if ((ret == 1) && (pfd.revents & (POLLIN|POLLHUP|POLLERR))) {
/* Do the Read */
int result = read(fd, (char *)buffer + nread,
count - nread);
if ((result == -1) || (result == 0)) {
/* Read failed. I think the only useful thing we
can do here is just return -1 and fail since the
transaction has failed half way through. */
winbind_close_sock();
return -1;
}
nread += result;
}
}
return nread;
}
/* Read reply */
static int winbindd_read_reply(struct winbindd_response *response)
{
int result1, result2 = 0;
if (!response) {
return -1;
}
/* Read fixed length response */
result1 = winbind_read_sock(response,
sizeof(struct winbindd_response));
if (result1 == -1) {
return -1;
}
if (response->length < sizeof(struct winbindd_response)) {
return -1;
}
/* We actually send the pointer value of the extra_data field from
the server. This has no meaning in the client's address space
so we clear it out. */
response->extra_data.data = NULL;
/* Read variable length response */
if (response->length > sizeof(struct winbindd_response)) {
int extra_data_len = response->length -
sizeof(struct winbindd_response);
/* Mallocate memory for extra data */
if (!(response->extra_data.data = malloc(extra_data_len))) {
return -1;
}
result2 = winbind_read_sock(response->extra_data.data,
extra_data_len);
if (result2 == -1) {
winbindd_free_response(response);
return -1;
}
}
/* Return total amount of data read */
return result1 + result2;
}
/*
* send simple types of requests
*/
NSS_STATUS winbindd_send_request(int req_type, int need_priv,
struct winbindd_request *request)
{
struct winbindd_request lrequest;
/* Check for our tricky environment variable */
if (winbind_env_set()) {
return NSS_STATUS_NOTFOUND;
}
if (!request) {
ZERO_STRUCT(lrequest);
request = &lrequest;
}
/* Fill in request and send down pipe */
winbindd_init_request(request, req_type);
if (winbind_write_sock(request, sizeof(*request),
request->wb_flags & WBFLAG_RECURSE,
need_priv) == -1)
{
/* Set ENOENT for consistency. Required by some apps */
errno = ENOENT;
return NSS_STATUS_UNAVAIL;
}
if ((request->extra_len != 0) &&
(winbind_write_sock(request->extra_data.data,
request->extra_len,
request->wb_flags & WBFLAG_RECURSE,
need_priv) == -1))
{
/* Set ENOENT for consistency. Required by some apps */
errno = ENOENT;
return NSS_STATUS_UNAVAIL;
}
return NSS_STATUS_SUCCESS;
}
/*
* Get results from winbindd request
*/
NSS_STATUS winbindd_get_response(struct winbindd_response *response)
{
struct winbindd_response lresponse;
if (!response) {
ZERO_STRUCT(lresponse);
response = &lresponse;
}
init_response(response);
/* Wait for reply */
if (winbindd_read_reply(response) == -1) {
/* Set ENOENT for consistency. Required by some apps */
errno = ENOENT;
return NSS_STATUS_UNAVAIL;
}
/* Throw away extra data if client didn't request it */
if (response == &lresponse) {
winbindd_free_response(response);
}
/* Copy reply data from socket */
if (response->result != WINBINDD_OK) {
return NSS_STATUS_NOTFOUND;
}
return NSS_STATUS_SUCCESS;
}
/* Handle simple types of requests */
NSS_STATUS winbindd_request_response(int req_type,
struct winbindd_request *request,
struct winbindd_response *response)
{
NSS_STATUS status = NSS_STATUS_UNAVAIL;
int count = 0;
while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
status = winbindd_send_request(req_type, 0, request);
if (status != NSS_STATUS_SUCCESS)
return(status);
status = winbindd_get_response(response);
count += 1;
}
return status;
}
NSS_STATUS winbindd_priv_request_response(int req_type,
struct winbindd_request *request,
struct winbindd_response *response)
{
NSS_STATUS status = NSS_STATUS_UNAVAIL;
int count = 0;
while ((status == NSS_STATUS_UNAVAIL) && (count < 10)) {
status = winbindd_send_request(req_type, 1, request);
if (status != NSS_STATUS_SUCCESS)
return(status);
status = winbindd_get_response(response);
count += 1;
}
return status;
}