When ``ppp -direct'' is invoked by a program that uses pipe(2) to
create stdin and stdout, don't blindly try to use stdin as a bi-directional channel. Instead, detect the pipe and set up a special exec handler that indirects write() calls through stdout. This fixes the problem where ``set device "!ssh -e none host ppp -direct label"'' no longer works with an openssh-5.2 server side as that version of openssh ignores the USE_PIPES config setting and *always* uses pipes (rather than socketpair) for stdin/stdout channels. MFC after: 3 days
This commit is contained in:
Brian Somers
parent
c5e246d446
commit
887ff31f06
@ -35,7 +35,9 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sysexits.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <sys/uio.h>
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#include <termios.h>
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#include <unistd.h>
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@ -63,24 +65,106 @@
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#include "cbcp.h"
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#include "datalink.h"
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#include "id.h"
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#include "main.h"
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#include "exec.h"
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static struct device execdevice = {
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struct execdevice {
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struct device dev; /* What struct physical knows about */
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int fd_out; /* output descriptor */
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};
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#define device2exec(d) ((d)->type == EXEC_DEVICE ? (struct execdevice *)d : NULL)
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unsigned
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exec_DeviceSize(void)
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{
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return sizeof(struct execdevice);
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}
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static void
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exec_Free(struct physical *p)
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{
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struct execdevice *dev = device2exec(p->handler);
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if (dev->fd_out != -1)
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close(dev->fd_out);
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free(dev);
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}
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static void
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exec_device2iov(struct device *d, struct iovec *iov, int *niov,
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int maxiov __unused, int *auxfd, int *nauxfd)
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{
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struct execdevice *dev;
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int sz = physical_MaxDeviceSize();
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iov[*niov].iov_base = d = realloc(d, sz);
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if (d == NULL) {
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log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz);
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AbortProgram(EX_OSERR);
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}
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iov[*niov].iov_len = sz;
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(*niov)++;
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dev = device2exec(d);
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if (dev->fd_out >= 0) {
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*auxfd = dev->fd_out;
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(*nauxfd)++;
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}
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}
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static int
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exec_RemoveFromSet(struct physical *p, fd_set *r, fd_set *w, fd_set *e)
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{
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struct execdevice *dev = device2exec(p->handler);
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int sets;
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p->handler->removefromset = NULL;
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sets = physical_RemoveFromSet(p, r, w, e);
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p->handler->removefromset = exec_RemoveFromSet;
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if (dev->fd_out >= 0) {
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if (w && FD_ISSET(dev->fd_out, w)) {
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FD_CLR(dev->fd_out, w);
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log_Printf(LogTIMER, "%s: fdunset(w) %d\n", p->link.name, dev->fd_out);
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sets++;
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}
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if (e && FD_ISSET(dev->fd_out, e)) {
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FD_CLR(dev->fd_out, e);
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log_Printf(LogTIMER, "%s: fdunset(e) %d\n", p->link.name, dev->fd_out);
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sets++;
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}
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}
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return sets;
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}
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static ssize_t
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exec_Write(struct physical *p, const void *v, size_t n)
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{
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struct execdevice *dev = device2exec(p->handler);
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int fd = dev->fd_out == -1 ? p->fd : dev->fd_out;
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return write(fd, v, n);
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}
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static struct device baseexecdevice = {
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EXEC_DEVICE,
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"exec",
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0,
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{ CD_NOTREQUIRED, 0 },
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NULL,
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exec_RemoveFromSet,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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exec_Free,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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exec_Write,
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exec_device2iov,
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NULL,
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NULL,
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NULL
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@ -88,146 +172,238 @@ static struct device execdevice = {
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struct device *
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exec_iov2device(int type, struct physical *p, struct iovec *iov,
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int *niov, int maxiov __unused, int *auxfd __unused,
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int *nauxfd __unused)
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int *niov, int maxiov __unused, int *auxfd, int *nauxfd)
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{
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if (type == EXEC_DEVICE) {
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free(iov[(*niov)++].iov_base);
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physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
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return &execdevice;
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struct execdevice *dev = (struct execdevice *)iov[(*niov)++].iov_base;
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dev = realloc(dev, sizeof *dev); /* Reduce to the correct size */
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if (dev == NULL) {
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log_Printf(LogALERT, "Failed to allocate memory: %d\n",
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(int)(sizeof *dev));
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AbortProgram(EX_OSERR);
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}
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if (*nauxfd) {
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dev->fd_out = *auxfd;
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(*nauxfd)--;
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} else
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dev->fd_out = -1;
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/* Refresh function pointers etc */
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memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev);
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physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
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return &dev->dev;
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}
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return NULL;
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}
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static int
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exec_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
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{
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struct physical *p = descriptor2physical(d);
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struct execdevice *dev = device2exec(p->handler);
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int result = 0;
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if (w && dev->fd_out >= 0) {
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FD_SET(dev->fd_out, w);
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log_Printf(LogTIMER, "%s: fdset(w) %d\n", p->link.name, dev->fd_out);
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result++;
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w = NULL;
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}
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if (e && dev->fd_out >= 0) {
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FD_SET(dev->fd_out, e);
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log_Printf(LogTIMER, "%s: fdset(e) %d\n", p->link.name, dev->fd_out);
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result++;
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}
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if (result && *n <= dev->fd_out)
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*n = dev->fd_out + 1;
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return result + physical_doUpdateSet(d, r, w, e, n, 0);
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}
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static int
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exec_IsSet(struct fdescriptor *d, const fd_set *fdset)
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{
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struct physical *p = descriptor2physical(d);
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struct execdevice *dev = device2exec(p->handler);
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int result = dev->fd_out >= 0 && FD_ISSET(dev->fd_out, fdset);
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result += physical_IsSet(d, fdset);
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return result;
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}
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struct device *
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exec_Create(struct physical *p)
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{
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if (p->fd < 0 && *p->name.full == '!') {
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int fids[2], type;
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struct execdevice *dev;
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p->fd--; /* We own the device but maybe can't use it - change fd */
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type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM;
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if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0)
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log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
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strerror(errno));
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else {
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static int child_status; /* This variable is abused ! */
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int stat, argc, i, ret, wret, pidpipe[2];
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pid_t pid, realpid;
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char *argv[MAXARGS];
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stat = fcntl(fids[0], F_GETFL, 0);
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if (stat > 0) {
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stat |= O_NONBLOCK;
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fcntl(fids[0], F_SETFL, stat);
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dev = NULL;
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if (p->fd < 0) {
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if (*p->name.full == '!') {
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int fids[2], type;
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if ((dev = malloc(sizeof *dev)) == NULL) {
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log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n",
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p->link.name, strerror(errno));
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return NULL;
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}
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realpid = getpid();
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if (pipe(pidpipe) == -1) {
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log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n",
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dev->fd_out = -1;
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p->fd--; /* We own the device but maybe can't use it - change fd */
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type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM;
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if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0) {
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log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
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strerror(errno));
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close(fids[1]);
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} else switch ((pid = fork())) {
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case -1:
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log_Printf(LogPHASE, "Unable to fork for line exec: %s\n",
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free(dev);
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dev = NULL;
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} else {
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static int child_status; /* This variable is abused ! */
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int stat, argc, i, ret, wret, pidpipe[2];
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pid_t pid, realpid;
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char *argv[MAXARGS];
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stat = fcntl(fids[0], F_GETFL, 0);
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if (stat > 0) {
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stat |= O_NONBLOCK;
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fcntl(fids[0], F_SETFL, stat);
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}
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realpid = getpid();
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if (pipe(pidpipe) == -1) {
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log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n",
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strerror(errno));
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close(pidpipe[0]);
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close(pidpipe[1]);
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close(fids[1]);
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break;
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case 0:
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close(pidpipe[0]);
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close(fids[0]);
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timer_TermService();
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#ifndef NOSUID
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setuid(ID0realuid());
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#endif
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child_status = 0;
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switch ((pid = vfork())) {
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case 0:
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close(pidpipe[1]);
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break;
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case -1:
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ret = errno;
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log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n",
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strerror(errno));
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close(pidpipe[1]);
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_exit(ret);
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default:
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write(pidpipe[1], &pid, sizeof pid);
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close(pidpipe[1]);
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_exit(child_status); /* The error from exec() ! */
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}
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log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
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if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
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PARSE_REDUCE|PARSE_NOHASH)) < 0) {
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log_Printf(LogWARN, "Syntax error in exec command\n");
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_exit(ESRCH);
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}
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command_Expand(argv, argc, (char const *const *)argv,
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p->dl->bundle, 0, realpid);
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dup2(fids[1], STDIN_FILENO);
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dup2(fids[1], STDOUT_FILENO);
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dup2(fids[1], STDERR_FILENO);
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for (i = getdtablesize(); i > STDERR_FILENO; i--)
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fcntl(i, F_SETFD, 1);
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execvp(*argv, argv);
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child_status = errno; /* Only works for vfork() */
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printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
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_exit(child_status);
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break;
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default:
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close(pidpipe[1]);
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close(fids[1]);
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if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) !=
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sizeof p->session_owner)
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p->session_owner = (pid_t)-1;
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close(pidpipe[0]);
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while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
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;
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if (wret == -1) {
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log_Printf(LogWARN, "Waiting for child process: %s\n",
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free(dev);
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dev = NULL;
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} else switch ((pid = fork())) {
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case -1:
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log_Printf(LogPHASE, "Unable to fork for line exec: %s\n",
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strerror(errno));
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close(pidpipe[0]);
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close(pidpipe[1]);
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close(fids[1]);
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close(fids[0]);
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p->session_owner = (pid_t)-1;
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break;
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} else if (WIFSIGNALED(stat)) {
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log_Printf(LogWARN, "Child process received sig %d !\n",
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WTERMSIG(stat));
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case 0:
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close(pidpipe[0]);
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close(fids[0]);
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p->session_owner = (pid_t)-1;
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timer_TermService();
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#ifndef NOSUID
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setuid(ID0realuid());
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#endif
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child_status = 0;
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switch ((pid = vfork())) {
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case 0:
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close(pidpipe[1]);
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break;
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case -1:
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ret = errno;
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log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n",
|
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strerror(errno));
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close(pidpipe[1]);
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_exit(ret);
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default:
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write(pidpipe[1], &pid, sizeof pid);
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close(pidpipe[1]);
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_exit(child_status); /* The error from exec() ! */
|
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}
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log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
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|
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if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
|
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PARSE_REDUCE|PARSE_NOHASH)) < 0) {
|
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log_Printf(LogWARN, "Syntax error in exec command\n");
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_exit(ESRCH);
|
||||
}
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|
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command_Expand(argv, argc, (char const *const *)argv,
|
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p->dl->bundle, 0, realpid);
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|
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dup2(fids[1], STDIN_FILENO);
|
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dup2(fids[1], STDOUT_FILENO);
|
||||
dup2(fids[1], STDERR_FILENO);
|
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for (i = getdtablesize(); i > STDERR_FILENO; i--)
|
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fcntl(i, F_SETFD, 1);
|
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|
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execvp(*argv, argv);
|
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child_status = errno; /* Only works for vfork() */
|
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printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
|
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_exit(child_status);
|
||||
break;
|
||||
} else if (WIFSTOPPED(stat)) {
|
||||
log_Printf(LogWARN, "Child process received stop sig %d !\n",
|
||||
WSTOPSIG(stat));
|
||||
/* I guess that's ok.... */
|
||||
} else if ((ret = WEXITSTATUS(stat))) {
|
||||
log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
|
||||
strerror(ret));
|
||||
close(fids[0]);
|
||||
p->session_owner = (pid_t)-1;
|
||||
break;
|
||||
}
|
||||
p->fd = fids[0];
|
||||
log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
|
||||
physical_SetupStack(p, execdevice.name, PHYSICAL_NOFORCE);
|
||||
if (p->cfg.cd.necessity != CD_DEFAULT)
|
||||
log_Printf(LogWARN, "Carrier settings ignored\n");
|
||||
return &execdevice;
|
||||
|
||||
default:
|
||||
close(pidpipe[1]);
|
||||
close(fids[1]);
|
||||
if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) !=
|
||||
sizeof p->session_owner)
|
||||
p->session_owner = (pid_t)-1;
|
||||
close(pidpipe[0]);
|
||||
while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
|
||||
;
|
||||
if (wret == -1) {
|
||||
log_Printf(LogWARN, "Waiting for child process: %s\n",
|
||||
strerror(errno));
|
||||
close(fids[0]);
|
||||
p->session_owner = (pid_t)-1;
|
||||
break;
|
||||
} else if (WIFSIGNALED(stat)) {
|
||||
log_Printf(LogWARN, "Child process received sig %d !\n",
|
||||
WTERMSIG(stat));
|
||||
close(fids[0]);
|
||||
p->session_owner = (pid_t)-1;
|
||||
break;
|
||||
} else if (WIFSTOPPED(stat)) {
|
||||
log_Printf(LogWARN, "Child process received stop sig %d !\n",
|
||||
WSTOPSIG(stat));
|
||||
/* I guess that's ok.... */
|
||||
} else if ((ret = WEXITSTATUS(stat))) {
|
||||
log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
|
||||
strerror(ret));
|
||||
close(fids[0]);
|
||||
p->session_owner = (pid_t)-1;
|
||||
break;
|
||||
}
|
||||
p->fd = fids[0];
|
||||
log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
|
||||
}
|
||||
}
|
||||
close(fids[0]);
|
||||
}
|
||||
} else {
|
||||
struct stat st;
|
||||
|
||||
if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFIFO)) {
|
||||
if ((dev = malloc(sizeof *dev)) == NULL)
|
||||
log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n",
|
||||
p->link.name, strerror(errno));
|
||||
else if (p->fd == STDIN_FILENO) {
|
||||
log_Printf(LogPHASE, "%s: Using stdin/stdout to communicate with "
|
||||
"parent (pipe mode)\n", p->link.name);
|
||||
dev->fd_out = dup(STDOUT_FILENO);
|
||||
|
||||
/* Hook things up so that we monitor dev->fd_out */
|
||||
p->desc.UpdateSet = exec_UpdateSet;
|
||||
p->desc.IsSet = exec_IsSet;
|
||||
} else
|
||||
dev->fd_out = -1;
|
||||
}
|
||||
}
|
||||
|
||||
if (dev) {
|
||||
memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev);
|
||||
physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
|
||||
if (p->cfg.cd.necessity != CD_DEFAULT)
|
||||
log_Printf(LogWARN, "Carrier settings ignored\n");
|
||||
return &dev->dev;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
|
||||
@ -32,4 +32,4 @@ struct device;
|
||||
extern struct device *exec_Create(struct physical *);
|
||||
extern struct device *exec_iov2device(int, struct physical *,
|
||||
struct iovec *, int *, int, int *, int *);
|
||||
#define exec_DeviceSize physical_DeviceSize
|
||||
extern unsigned exec_DeviceSize(void);
|
||||
|
||||
@ -509,9 +509,11 @@ main(int argc, char **argv)
|
||||
if (!sw.fg)
|
||||
setsid();
|
||||
} else {
|
||||
/* -direct - STDIN_FILENO gets used by physical_Open */
|
||||
/*
|
||||
* -direct - STDIN_FILENO gets used by physical_Open. STDOUT_FILENO
|
||||
* *may* get used in exec/pipe mode.
|
||||
*/
|
||||
prompt_TtyInit(NULL);
|
||||
close(STDOUT_FILENO);
|
||||
close(STDERR_FILENO);
|
||||
}
|
||||
} else {
|
||||
|
||||
@ -1017,6 +1017,7 @@ physical_Open(struct physical *p)
|
||||
p->fd = STDIN_FILENO;
|
||||
for (h = 0; h < NDEVICES && p->handler == NULL && p->fd >= 0; h++)
|
||||
p->handler = (*devices[h].create)(p);
|
||||
close(STDOUT_FILENO);
|
||||
if (p->fd >= 0) {
|
||||
if (p->handler == NULL) {
|
||||
physical_SetupStack(p, "unknown", PHYSICAL_NOFORCE);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user