Run pg_upgrade and pg_resetxlog with restricted token on Windows

As with initdb these programs need to run with a restricted token, and
if they don't pg_upgrade will fail when run as a user with Adminstrator
privileges.

Backpatch to all live branches. On the development branch the code is
reorganized so that the restricted token code is now in a single
location. On the stable bramches a less invasive change is made by
simply copying the relevant code to pg_upgrade.c and pg_resetxlog.c.

Patches and bug report from Muhammad Asif Naeem, reviewed by Michael
Paquier, slightly edited by me.

diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
index a106511b4da98e43d9a9aa2588bc7dd3dff94280..89e427503a70604a12994a2ff0f9b9d6b6d9f130 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.c
+++ b/contrib/pg_upgrade/pg_upgrade.c
@@ -50,6 +50,11 @@ static void copy_clog_xlog_xid(void);
 static void set_frozenxids(void);
 static void setup(char *argv0, bool live_check);
 static void cleanup(void);
+static void    get_restricted_token(const char *progname);
+
+#ifdef WIN32
+static int     CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char *progname);
+#endif
 
 ClusterInfo old_cluster,
                        new_cluster;
@@ -67,6 +72,9 @@ char     *output_files[] = {
        NULL
 };
 
+#ifdef WIN32
+static char *restrict_env;
+#endif
 
 int
 main(int argc, char **argv)
@@ -78,6 +86,8 @@ main(int argc, char **argv)
 
        parseCommandLine(argc, argv);
 
+       get_restricted_token(os_info.progname);
+
        adjust_data_dir(&old_cluster);
        adjust_data_dir(&new_cluster);
 
@@ -170,6 +180,162 @@ main(int argc, char **argv)
        return 0;
 }
 
+#ifdef WIN32
+typedef BOOL(WINAPI * __CreateRestrictedToken) (HANDLE, DWORD, DWORD, PSID_AND_ATTRIBUTES, DWORD, PLUID_AND_ATTRIBUTES, DWORD, PSID_AND_ATTRIBUTES, PHANDLE);
+
+/* Windows API define missing from some versions of MingW headers */
+#ifndef  DISABLE_MAX_PRIVILEGE
+#define DISABLE_MAX_PRIVILEGE  0x1
+#endif
+
+/*
+* Create a restricted token and execute the specified process with it.
+*
+* Returns 0 on failure, non-zero on success, same as CreateProcess().
+*
+* On NT4, or any other system not containing the required functions, will
+* NOT execute anything.
+*/
+static int
+CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char *progname)
+{
+       BOOL            b;
+       STARTUPINFO si;
+       HANDLE          origToken;
+       HANDLE          restrictedToken;
+       SID_IDENTIFIER_AUTHORITY NtAuthority = { SECURITY_NT_AUTHORITY };
+       SID_AND_ATTRIBUTES dropSids[2];
+       __CreateRestrictedToken _CreateRestrictedToken = NULL;
+       HANDLE          Advapi32Handle;
+
+       ZeroMemory(&si, sizeof(si));
+       si.cb = sizeof(si);
+
+       Advapi32Handle = LoadLibrary("ADVAPI32.DLL");
+       if (Advapi32Handle != NULL)
+       {
+               _CreateRestrictedToken = (__CreateRestrictedToken)GetProcAddress(Advapi32Handle, "CreateRestrictedToken");
+       }
+
+       if (_CreateRestrictedToken == NULL)
+       {
+               fprintf(stderr, _("%s: WARNING: cannot create restricted tokens on this platform\n"), progname);
+               if (Advapi32Handle != NULL)
+                       FreeLibrary(Advapi32Handle);
+               return 0;
+       }
+
+       /* Open the current token to use as a base for the restricted one */
+       if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &origToken))
+       {
+               fprintf(stderr, _("%s: could not open process token: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+       /* Allocate list of SIDs to remove */
+       ZeroMemory(&dropSids, sizeof(dropSids));
+       if (!AllocateAndInitializeSid(&NtAuthority, 2,
+               SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0,
+               0, &dropSids[0].Sid) ||
+               !AllocateAndInitializeSid(&NtAuthority, 2,
+               SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_POWER_USERS, 0, 0, 0, 0, 0,
+               0, &dropSids[1].Sid))
+       {
+               fprintf(stderr, _("%s: could not to allocate SIDs: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+       b = _CreateRestrictedToken(origToken,
+                                               DISABLE_MAX_PRIVILEGE,
+                                               sizeof(dropSids) / sizeof(dropSids[0]),
+                                               dropSids,
+                                               0, NULL,
+                                               0, NULL,
+                                               &restrictedToken);
+
+       FreeSid(dropSids[1].Sid);
+       FreeSid(dropSids[0].Sid);
+       CloseHandle(origToken);
+       FreeLibrary(Advapi32Handle);
+
+       if (!b)
+       {
+               fprintf(stderr, _("%s: could not create restricted token: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+#ifndef __CYGWIN__
+       AddUserToTokenDacl(restrictedToken);
+#endif
+
+       if (!CreateProcessAsUser(restrictedToken,
+                                                       NULL,
+                                                       cmd,
+                                                       NULL,
+                                                       NULL,
+                                                       TRUE,
+                                                       CREATE_SUSPENDED,
+                                                       NULL,
+                                                       NULL,
+                                                       &si,
+                                                       processInfo))
+
+       {
+               fprintf(stderr, _("%s: could not start process for command \"%s\": error code %lu\n"), progname, cmd, GetLastError());
+               return 0;
+       }
+
+       return ResumeThread(processInfo->hThread);
+}
+#endif
+
+void
+get_restricted_token(const char *progname)
+{
+#ifdef WIN32
+
+       /*
+       * Before we execute another program, make sure that we are running with a
+       * restricted token. If not, re-execute ourselves with one.
+       */
+
+       if ((restrict_env = getenv("PG_RESTRICT_EXEC")) == NULL
+               || strcmp(restrict_env, "1") != 0)
+       {
+               PROCESS_INFORMATION pi;
+               char       *cmdline;
+
+               ZeroMemory(&pi, sizeof(pi));
+
+               cmdline = pg_strdup(GetCommandLine());
+
+               putenv("PG_RESTRICT_EXEC=1");
+
+               if (!CreateRestrictedProcess(cmdline, &pi, progname))
+               {
+                       fprintf(stderr, _("%s: could not re-execute with restricted token: error code %lu\n"), progname, GetLastError());
+               }
+               else
+               {
+                       /*
+                       * Successfully re-execed. Now wait for child process to capture
+                       * exitcode.
+                       */
+                       DWORD           x;
+
+                       CloseHandle(pi.hThread);
+                       WaitForSingleObject(pi.hProcess, INFINITE);
+
+                       if (!GetExitCodeProcess(pi.hProcess, &x))
+                       {
+                               fprintf(stderr, _("%s: could not get exit code from subprocess: error code %lu\n"), progname, GetLastError());
+                               exit(1);
+                       }
+                       exit(x);
+               }
+       }
+#endif
+}
 
 static void
 setup(char *argv0, bool live_check)

diff --git a/src/bin/pg_resetxlog/pg_resetxlog.c b/src/bin/pg_resetxlog/pg_resetxlog.c
index 92d98fc963cbdd16abe5759511c2284d72d8e3d6..24de764f5c998f659e6db663d21526ed49ff2923 100644 (file)
--- a/src/bin/pg_resetxlog/pg_resetxlog.c
+++ b/src/bin/pg_resetxlog/pg_resetxlog.c
@@ -65,6 +65,10 @@ static uint32 newXlogId,
 static bool guessed = false;   /* T if we had to guess at any values */
 static const char *progname;
 
+#ifdef WIN32
+static char *restrict_env;
+#endif
+
 static bool ReadControlFile(void);
 static void GuessControlValues(void);
 static void PrintControlValues(bool guessed);
@@ -74,7 +78,12 @@ static void KillExistingXLOG(void);
 static void KillExistingArchiveStatus(void);
 static void WriteEmptyXLOG(void);
 static void usage(void);
+static void    get_restricted_token(const char *progname);
 
+#ifdef WIN32
+static int     CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char *progname);
+static char *pg_strdup(const char *str);
+#endif
 
 int
 main(int argc, char *argv[])
@@ -256,6 +265,7 @@ main(int argc, char *argv[])
        }
 #endif
 
+       get_restricted_token(progname);
        DataDir = argv[optind];
 
        if (chdir(DataDir) < 0)
@@ -380,6 +390,20 @@ main(int argc, char *argv[])
        return 0;
 }
 
+#ifdef WIN32
+static char *
+pg_strdup(const char *str)
+{
+       char    *result = strdup(str);
+
+       if (!result)
+       {
+               fprintf(stderr, _("out of memory\n"));
+               exit(1);
+       }
+       return result;
+}
+#endif
 
 /*
  * Try to read the existing pg_control file.
@@ -1022,6 +1046,162 @@ WriteEmptyXLOG(void)
        close(fd);
 }
 
+#ifdef WIN32
+typedef BOOL(WINAPI * __CreateRestrictedToken) (HANDLE, DWORD, DWORD, PSID_AND_ATTRIBUTES, DWORD, PLUID_AND_ATTRIBUTES, DWORD, PSID_AND_ATTRIBUTES, PHANDLE);
+
+/* Windows API define missing from some versions of MingW headers */
+#ifndef  DISABLE_MAX_PRIVILEGE
+#define DISABLE_MAX_PRIVILEGE  0x1
+#endif
+
+/*
+* Create a restricted token and execute the specified process with it.
+*
+* Returns 0 on failure, non-zero on success, same as CreateProcess().
+*
+* On NT4, or any other system not containing the required functions, will
+* NOT execute anything.
+*/
+static int
+CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char *progname)
+{
+       BOOL            b;
+       STARTUPINFO si;
+       HANDLE          origToken;
+       HANDLE          restrictedToken;
+       SID_IDENTIFIER_AUTHORITY NtAuthority = { SECURITY_NT_AUTHORITY };
+       SID_AND_ATTRIBUTES dropSids[2];
+       __CreateRestrictedToken _CreateRestrictedToken = NULL;
+       HANDLE          Advapi32Handle;
+
+       ZeroMemory(&si, sizeof(si));
+       si.cb = sizeof(si);
+
+       Advapi32Handle = LoadLibrary("ADVAPI32.DLL");
+       if (Advapi32Handle != NULL)
+       {
+               _CreateRestrictedToken = (__CreateRestrictedToken)GetProcAddress(Advapi32Handle, "CreateRestrictedToken");
+       }
+
+       if (_CreateRestrictedToken == NULL)
+       {
+               fprintf(stderr, _("%s: WARNING: cannot create restricted tokens on this platform\n"), progname);
+               if (Advapi32Handle != NULL)
+                       FreeLibrary(Advapi32Handle);
+               return 0;
+       }
+
+       /* Open the current token to use as a base for the restricted one */
+       if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &origToken))
+       {
+               fprintf(stderr, _("%s: could not open process token: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+       /* Allocate list of SIDs to remove */
+       ZeroMemory(&dropSids, sizeof(dropSids));
+       if (!AllocateAndInitializeSid(&NtAuthority, 2,
+               SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0,
+               0, &dropSids[0].Sid) ||
+               !AllocateAndInitializeSid(&NtAuthority, 2,
+               SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_POWER_USERS, 0, 0, 0, 0, 0,
+               0, &dropSids[1].Sid))
+       {
+               fprintf(stderr, _("%s: could not to allocate SIDs: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+       b = _CreateRestrictedToken(origToken,
+                                               DISABLE_MAX_PRIVILEGE,
+                                               sizeof(dropSids) / sizeof(dropSids[0]),
+                                               dropSids,
+                                               0, NULL,
+                                               0, NULL,
+                                               &restrictedToken);
+
+       FreeSid(dropSids[1].Sid);
+       FreeSid(dropSids[0].Sid);
+       CloseHandle(origToken);
+       FreeLibrary(Advapi32Handle);
+
+       if (!b)
+       {
+               fprintf(stderr, _("%s: could not create restricted token: error code %lu\n"), progname, GetLastError());
+               return 0;
+       }
+
+#ifndef __CYGWIN__
+       AddUserToTokenDacl(restrictedToken);
+#endif
+
+       if (!CreateProcessAsUser(restrictedToken,
+                                                       NULL,
+                                                       cmd,
+                                                       NULL,
+                                                       NULL,
+                                                       TRUE,
+                                                       CREATE_SUSPENDED,
+                                                       NULL,
+                                                       NULL,
+                                                       &si,
+                                                       processInfo))
+
+       {
+               fprintf(stderr, _("%s: could not start process for command \"%s\": error code %lu\n"), progname, cmd, GetLastError());
+               return 0;
+       }
+
+       return ResumeThread(processInfo->hThread);
+}
+#endif
+
+void
+get_restricted_token(const char *progname)
+{
+#ifdef WIN32
+
+       /*
+       * Before we execute another program, make sure that we are running with a
+       * restricted token. If not, re-execute ourselves with one.
+       */
+
+       if ((restrict_env = getenv("PG_RESTRICT_EXEC")) == NULL
+               || strcmp(restrict_env, "1") != 0)
+       {
+               PROCESS_INFORMATION pi;
+               char       *cmdline;
+
+               ZeroMemory(&pi, sizeof(pi));
+
+               cmdline = pg_strdup(GetCommandLine());
+
+               putenv("PG_RESTRICT_EXEC=1");
+
+               if (!CreateRestrictedProcess(cmdline, &pi, progname))
+               {
+                       fprintf(stderr, _("%s: could not re-execute with restricted token: error code %lu\n"), progname, GetLastError());
+               }
+               else
+               {
+                       /*
+                       * Successfully re-execed. Now wait for child process to capture
+                       * exitcode.
+                       */
+                       DWORD           x;
+
+                       CloseHandle(pi.hThread);
+                       WaitForSingleObject(pi.hProcess, INFINITE);
+
+                       if (!GetExitCodeProcess(pi.hProcess, &x))
+                       {
+                               fprintf(stderr, _("%s: could not get exit code from subprocess: error code %lu\n"), progname, GetLastError());
+                               exit(1);
+                       }
+                       exit(x);
+               }
+       }
+#endif
+}
 
 static void
 usage(void)