POTD skeleton #42.

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>

1 files changed, 55 insertions, 30 deletions

diff --git a/src/jail.c b/src/jail.c
index e879c2c..b45f7c8 100644
--- a/src/jail.c
+++ b/src/jail.c
@@ -12,7 +12,6 @@
 #include "jail.h"
 #include "socket.h"
 #include "server.h"
-#include "pterm.h"
 #include "utils.h"
 #include "log.h"
 
@@ -26,8 +25,9 @@ static int jail_mainloop_epoll(int epoll_fd, jail_ctx *ctx[], size_t siz)
     __attribute__((noreturn));
 static int jail_accept_client(jail_ctx *ctx[],
                               size_t siz, struct epoll_event *event);
-static int jail_childfn(void *arg)
+static int jail_childfn(jail_prisoner_process *ctx)
     __attribute__((noreturn));
+static int jail_socket_tty_epoll(jail_prisoner_process *ctx, int tty_fd);
 
 
 void jail_init_ctx(jail_ctx **ctx, size_t stacksize)
@@ -259,85 +259,78 @@ error:
     return rc;
 }
 
-static int jail_childfn(void *arg)
+static int jail_childfn(jail_prisoner_process *ctx)
 {
-    jail_prisoner_process *args;
     const char *path_dev = "/dev";
     const char *path_devpts = "/dev/pts";
     const char *path_proc = "/proc";
     const char *path_shell = "/bin/sh";
-    char tty_name[TTYSZ+sizeof(long)];
-    int s, pty_fd, tty_fd;
+    int s, master_fd;
     int unshare_flags = CLONE_NEWUTS|CLONE_NEWPID|CLONE_NEWIPC|
         CLONE_NEWNS|CLONE_NEWNET;
     pid_t self_pid, child_pid;
 
-    assert(arg);
-    args = (jail_prisoner_process *) arg;
+    assert(ctx);
     self_pid = getpid();
 
     if (prctl(PR_SET_PDEATHSIG, SIGKILL) != 0)
         FATAL("Jail child prctl for pid %d", self_pid);
-    if (!args->newroot)
+    if (!ctx->newroot)
         FATAL("New root set for pid %d", self_pid);
 
     D2("Unshare prisoner %d", self_pid);
     if (unshare(unshare_flags))
         FATAL("Unshare prisoner %d", self_pid);
 
-    D2("Safe change root to: '%s'", args->newroot);
-    if (safe_chroot(args->newroot))
-        FATAL("Safe jail chroot to '%s' failed", args->newroot);
+    D2("Safe change root to: '%s'", ctx->newroot);
+    if (safe_chroot(ctx->newroot))
+        FATAL("Safe jail chroot to '%s' failed", ctx->newroot);
 
-    D2("Mounting rootfs to '%s'", args->newroot);
+    D2("Mounting rootfs to '%s'", ctx->newroot);
     mount_root();
 
-    D2("Mounting devtmpfs to '%s%s'", args->newroot, path_dev);
+    D2("Mounting devtmpfs to '%s%s'", ctx->newroot, path_dev);
     s = mkdir(path_dev, S_IRUSR|S_IWUSR|S_IXUSR|
                         S_IRGRP|S_IXGRP|
                         S_IROTH|S_IXOTH);
     if (s && errno != EEXIST)
         FATAL("Create directory '%s'", path_dev);
     if (!dir_is_mountpoint(path_dev) && mount_dev(path_dev))
-        FATAL("Mount devtmpfs to '%s%s'", args->newroot, path_dev);
+        FATAL("Mount devtmpfs to '%s%s'", ctx->newroot, path_dev);
 
-    D2("Mounting devpts to '%s%s'", args->newroot, path_devpts);
+    D2("Mounting devpts to '%s%s'", ctx->newroot, path_devpts);
     s = mkdir(path_devpts, S_IRUSR|S_IWUSR|S_IXUSR|
                            S_IRGRP|S_IXGRP|
                            S_IROTH|S_IXOTH);
     if (s && errno != EEXIST)
         FATAL("Create directory '%s'", path_devpts);
     if (!dir_is_mountpoint(path_devpts) && mount_pts(path_devpts))
-        FATAL("Mount devpts to '%s%s'", args->newroot, path_devpts);
+        FATAL("Mount devpts to '%s%s'", ctx->newroot, path_devpts);
 
-    D2("Mounting proc to '%s%s'", args->newroot, path_proc);
+    D2("Mounting proc to '%s%s'", ctx->newroot, path_proc);
     s = mkdir(path_proc, S_IRUSR|S_IWUSR|S_IXUSR|
                          S_IRGRP|S_IXGRP|
                          S_IROTH|S_IXOTH);
     if (s && errno != EEXIST)
         FATAL("Create directory '%s'", path_proc);
     if (!dir_is_mountpoint(path_proc) && mount_proc(path_proc))
-        FATAL("Mount devpts to '%s%s'", args->newroot, path_proc)
+        FATAL("Mount devpts to '%s%s'", ctx->newroot, path_proc)
 
-    D2("Creating device files in '%s%s'", args->newroot, path_dev);
+    D2("Creating device files in '%s%s'", ctx->newroot, path_dev);
     if (create_device_files(path_dev)) {
         E2("Device file creation failed for rootfs '%s%s'",
-            args->newroot, path_dev);
+            ctx->newroot, path_dev);
         exit(EXIT_FAILURE);
     }
 
-    if (pty_allocate(&pty_fd, &tty_fd, tty_name, TTYSZ))
-        FATAL("%s", "TTY allocation");
-
-    D2("Forking a new process for the slave tty from "
-       "parent pty with pid %d",
-       self_pid);
-    child_pid = fork();
+    D2("Forking a new pty process for "
+       "parent %d", self_pid);
+    child_pid = forkpty(&master_fd, NULL, NULL, NULL);
     switch (child_pid) {
         case -1:
             FATAL("Forking a new process for the slave tty from "
-                  "parent pty with pid %d",
-                  self_pid);
+                "parent pty with pid %d",
+                self_pid);
             break;
         case 0:
             D2("Executing '%s'", path_shell);
@@ -345,8 +338,40 @@ static int jail_childfn(void *arg)
                 FATAL("Execute a shell for pid %d", self_pid);
             break;
         default:
+            if (set_fd_nonblock(master_fd))
+                FATAL("Pty master fd nonblock for prisoner pid %d",
+                    child_pid);
+            N("Socket to tty I/O loop for prisoner pid %d",
+                child_pid);
+            if (jail_socket_tty_epoll(ctx, master_fd))
+                FATAL("Socket to tty I/O loop for prisoner pid %d",
+                    child_pid);
             waitpid(child_pid, &s, 0);
     }
 
     exit(EXIT_FAILURE);
 }
+
+static int jail_socket_tty_epoll(jail_prisoner_process *ctx, int tty_fd)
+{
+    int s, fd = epoll_create1(0);
+    struct epoll_event event = {0,{0}};
+
+    assert(ctx);
+    if (fd < 0)
+        return -1;
+
+    event.events = EPOLLIN | EPOLLET;
+    event.data.fd = ctx->client_psock.fd;
+    s = epoll_ctl(fd, EPOLL_CTL_ADD, ctx->client_psock.fd, &event);
+    if (s)
+        FATAL("Jail Socket Epoll for client %s:%s",
+            ctx->host_buf, ctx->service_buf);
+    event.data.fd = tty_fd;
+    s = epoll_ctl(fd, EPOLL_CTL_ADD, tty_fd, &event);
+    if (s)
+        FATAL("Jail TTY Epoll for client %s:%s",
+            ctx->host_buf, ctx->service_buf);
+
+    return 0;
+}