New upstream version 2.0pre9.2

src/base/core/priv.c

@@ -0,0 +1,257 @@
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <grp.h>
+#ifdef HAVE_SYS_IO_H
+#include <sys/io.h>
+#endif
+#include "emu.h"
+#include "priv.h"
+#include "dosemu_config.h"
+#include "mapping.h"
+#include "utilities.h"
+#ifdef X86_EMULATOR
+#include "cpu-emu.h"
+#endif
+
+#if 0
+#define PRIV_TESTING
+#endif
+
+/* Some handy information to have around */
+static uid_t uid,euid;
+static gid_t gid,egid;
+static uid_t cur_uid, cur_euid;
+static gid_t cur_gid, cur_egid;
+
+static int skip_priv_setting = 0;
+
+int can_do_root_stuff;
+int under_root_login;
+int using_sudo;
+int current_iopl;
+
+#define PRIVS_ARE_ON (euid == cur_euid)
+#define PRIVS_ARE_OFF (uid == cur_euid)
+#define PRIVS_WERE_ON(privs) (pop_priv(privs))
+
+
+static void push_priv(saved_priv_status *privs)
+{
+  if (!privs || *privs != PRIV_MAGIC) {
+    error("Aiiiee... not in-sync saved priv status on push_priv\n");
+    leavedos(99);
+  }
+  *privs = PRIVS_ARE_ON;
+#ifdef PRIV_TESTING
+  c_printf("PRIV: pushing %d privs_ptr=%p\n", *privs, privs);
+#endif
+}
+
+static int pop_priv(saved_priv_status *privs)
+{
+  int ret;
+  if (!privs || *privs == PRIV_MAGIC) {
+    error("Aiiiee... not in-sync saved priv status on pop_priv\n");
+    leavedos(99);
+  }
+#ifdef PRIV_TESTING
+  c_printf("PRIV: popping %d privs_ptr=%p\n", *privs, privs);
+#endif
+  ret = (int)*privs;
+  *privs = PRIV_MAGIC;
+  return ret;
+}
+
+static int _priv_on(void)
+{
+  if (PRIVS_ARE_OFF) {  /* make sure the privs need to be changed */
+#ifdef PRIV_TESTING
+      c_printf("PRIV: on-in %d\n", cur_euid);
+#endif
+      if (setreuid(uid,euid)) {
+         error("Cannot turn privs on!\n");
+         return 0;
+      }
+      cur_uid = uid;
+      cur_euid = euid;
+      if (setregid(gid,egid)) {
+	  error("Cannot turn privs on!\n");
+	  return 0;
+      }
+      cur_gid = gid;
+      cur_egid = egid;
+  }
+#ifdef PRIV_TESTING
+  c_printf("PRIV: on-ex %d\n", cur_euid);
+#endif
+  return 1;
+}
+
+static int _priv_off(void)
+{
+  if (PRIVS_ARE_ON) {  /* make sure the privs need to be changed */
+#ifdef PRIV_TESTING
+      c_printf("PRIV: off-in %d\n", cur_euid);
+#endif
+      if (setreuid(euid,uid)) {
+	error("Cannot turn privs off!\n");
+	return 0;
+      }
+      cur_uid = euid;
+      cur_euid = uid;
+      if (setregid(egid,gid)) {
+	error("Cannot turn privs off!\n");
+	return 0;
+      }
+      cur_gid = egid;
+      cur_egid = gid;
+  }
+#ifdef PRIV_TESTING
+  c_printf("PRIV: off-ex %d\n", cur_euid);
+#endif
+  return 1;
+}
+
+int real_enter_priv_on(saved_priv_status *privs)
+{
+  if (skip_priv_setting) return 1;
+  push_priv(privs);
+  return _priv_on();
+}
+
+int real_enter_priv_off(saved_priv_status *privs)
+{
+  if (skip_priv_setting) return 1;
+  push_priv(privs);
+  return _priv_off();
+}
+
+int real_leave_priv_setting(saved_priv_status *privs)
+{
+  if (skip_priv_setting) return 1;
+  if (PRIVS_WERE_ON(privs)) return _priv_on();
+  return _priv_off();
+}
+
+int priv_iopl(int pl)
+{
+#ifdef HAVE_SYS_IO_H
+  int ret;
+  if (PRIVS_ARE_OFF) {
+    _priv_on();
+    ret = iopl(pl);
+    _priv_off();
+  }
+  else ret = iopl(pl);
+#ifdef X86_EMULATOR
+  if (config.cpu_vm == CPUVM_EMU) e_priv_iopl(pl);
+#endif
+  if (ret == 0)
+    current_iopl = pl;
+  return ret;
+#else
+  return -1;
+#endif
+}
+
+uid_t get_cur_uid(void)
+{
+  return cur_uid;
+}
+
+uid_t get_cur_euid(void)
+{
+  return cur_euid;
+}
+
+gid_t get_cur_egid(void)
+{
+  return cur_egid;
+}
+
+uid_t get_orig_uid(void)
+{
+  return uid;
+}
+
+uid_t get_orig_euid(void)
+{
+  return euid;
+}
+
+gid_t get_orig_gid(void)
+{
+  return gid;
+}
+
+int priv_drop(void)
+{
+  if (setreuid(uid,uid) || setregid(gid,gid))
+    {
+      error("Cannot drop root uid or gid!\n");
+      return 0;
+    }
+  cur_euid = euid = cur_uid = uid;
+  cur_egid = egid = cur_gid = gid;
+  skip_priv_setting = 1;
+  if (uid) can_do_root_stuff = 0;
+  return 1;
+}
+
+void priv_init(void)
+{
+  const char *sh = getenv("SUDO_HOME"); // theoretical future var
+  const char *h = getenv("HOME");
+  uid  = cur_uid  = getuid();
+  /* suid bit only sets euid & suid but not uid, sudo sets all 3 */
+  if (!uid) under_root_login = 1;
+  euid = cur_euid = geteuid();
+  if (!euid) can_do_root_stuff = 1;
+  if (!uid && !euid) skip_priv_setting = 1;
+  gid  = cur_gid  = getgid();
+  egid = cur_egid = getegid();
+
+  /* must store the /proc/self/exe symlink contents before dropping
+     privs! */
+  dosemu_proc_self_exe = readlink_malloc("/proc/self/exe");
+  /* For Fedora we must also save a file descriptor to /proc/self/maps */
+  dosemu_proc_self_maps_fd = open("/proc/self/maps", O_RDONLY | O_CLOEXEC);
+  if (!sh)
+    sh = getenv("DOSEMU_SUDO_HOME");
+  /* see if -E was used */
+  if (under_root_login && sh && h && strcmp(sh, h) == 0)
+  {
+    /* check for sudo and set to original user */
+    char *s = getenv("SUDO_GID");
+    if (s) {
+      gid = cur_gid = atoi(s);
+      if (gid) {
+        setregid(gid, egid);
+      }
+    }
+    s = getenv("SUDO_UID");
+    if (s) {
+      uid = cur_uid = atoi(s);
+      if (uid) {
+        skip_priv_setting = under_root_login = 0;
+	using_sudo = 1;
+	s = getenv("SUDO_USER");
+	if (s) {
+	  initgroups(s, gid);
+	  setenv("USER", s, 1);
+	}
+        setreuid(uid, euid);
+      }
+    }
+  }
+
+  if (!can_do_root_stuff)
+    {
+      skip_priv_setting = 1;
+    }
+
+  if (!skip_priv_setting) _priv_off();
+}