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Replace load of functions by direct calls for some WIN32

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This commit changes the following code paths to do direct system calls
to some WIN32 functions rather than loading them from an external
library, shaving some code in the process:
- Creation of restricted tokens in pg_ctl.c, introduced by a25cd81.
- QuerySecurityContextToken() in auth.c for SSPI authentication in the
backend, introduced in d602592.
- CreateRestrictedToken() in src/common/.  This change is similar to the
case of pg_ctl.c.

Most of these functions were loaded rather than directly called because,
as mentioned in the code comments, MinGW headers were not declaring
them.  I have double-checked the recent MinGW code, and all the
functions changed here are declared in its headers, so this change
should be safe.  Note that I do not have a MinGW environment at hand so
I have not tested it directly, but that MSVC was fine with the change.
The buildfarm will tell soon enough if this change is appropriate or not
for a much broader set of environments.

A few code paths still use GetProcAddress() to load some functions:
- LDAP authentication for ldap_start_tls_sA(), where I am not confident
that this change would work.
- win32env.c and win32ntdll.c where we have a per-MSVC version
dependency for the name of the library loaded.
- crashdump.c for MiniDumpWriteDump() and EnumDirTree(), where direct
calls were not able to work after testing.

Reported-by: Thomas Munro
Reviewed-by: Justin Prysby
Discussion: https://postgr.es/m/CA+hUKG+BMdcaCe=P-EjMoLTCr3zrrzqbcVE=8h5LyNsSVHKXZA@mail.gmail.com
pull/103/head
Michael Paquier 3 years ago
parent df4a056619
commit 47bd0b3fa6
3 changed files with 47 additions and 158 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 29
      src/backend/libpq/auth.c
  2. 137
      src/bin/pg_ctl/pg_ctl.c
  3. 39
      src/common/restricted_token.c

29
src/backend/libpq/auth.c
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@ -1201,11 +1201,8 @@ pg_SSPI_recvauth(Port *port)
DWORD accountnamesize = sizeof(accountname);
DWORD domainnamesize = sizeof(domainname);
SID_NAME_USE accountnameuse;
HMODULE secur32;
char *authn_id;
QUERY_SECURITY_CONTEXT_TOKEN_FN _QuerySecurityContextToken;
/*
* Acquire a handle to the server credentials.
*/
@ -1358,36 +1355,12 @@ pg_SSPI_recvauth(Port *port)
*
* Get the name of the user that authenticated, and compare it to the pg
* username that was specified for the connection.
*
* MingW is missing the export for QuerySecurityContextToken in the
* secur32 library, so we have to load it dynamically.
*/
secur32 = LoadLibrary("SECUR32.DLL");
if (secur32 == NULL)
ereport(ERROR,
(errmsg("could not load library \"%s\": error code %lu",
"SECUR32.DLL", GetLastError())));
_QuerySecurityContextToken = (QUERY_SECURITY_CONTEXT_TOKEN_FN) (pg_funcptr_t)
GetProcAddress(secur32, "QuerySecurityContextToken");
if (_QuerySecurityContextToken == NULL)
{
FreeLibrary(secur32);
ereport(ERROR,
(errmsg_internal("could not locate QuerySecurityContextToken in secur32.dll: error code %lu",
GetLastError())));
}
r = (_QuerySecurityContextToken) (sspictx, &token);
r = QuerySecurityContextToken(sspictx, &token);
if (r != SEC_E_OK)
{
FreeLibrary(secur32);
pg_SSPI_error(ERROR,
_("could not get token from SSPI security context"), r);
}
FreeLibrary(secur32);
/*
* No longer need the security context, everything from here on uses the

137
src/bin/pg_ctl/pg_ctl.c
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@ -1724,17 +1724,6 @@ pgwin32_doRunAsService(void)
}
/*
* Mingw headers are incomplete, and so are the libraries. So we have to load
* a whole lot of API functions dynamically.
*/
typedef BOOL (WINAPI * __CreateRestrictedToken) (HANDLE, DWORD, DWORD, PSID_AND_ATTRIBUTES, DWORD, PLUID_AND_ATTRIBUTES, DWORD, PSID_AND_ATTRIBUTES, PHANDLE);
typedef BOOL (WINAPI * __IsProcessInJob) (HANDLE, HANDLE, PBOOL);
typedef HANDLE (WINAPI * __CreateJobObject) (LPSECURITY_ATTRIBUTES, LPCTSTR);
typedef BOOL (WINAPI * __SetInformationJobObject) (HANDLE, JOBOBJECTINFOCLASS, LPVOID, DWORD);
typedef BOOL (WINAPI * __AssignProcessToJobObject) (HANDLE, HANDLE);
typedef BOOL (WINAPI * __QueryInformationJobObject) (HANDLE, JOBOBJECTINFOCLASS, LPVOID, DWORD, LPDWORD);
/*
* Set up STARTUPINFO for the new process to inherit this process' handles.
*
@ -1777,20 +1766,11 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_ser
STARTUPINFO si;
HANDLE origToken;
HANDLE restrictedToken;
BOOL inJob;
SID_IDENTIFIER_AUTHORITY NtAuthority = {SECURITY_NT_AUTHORITY};
SID_AND_ATTRIBUTES dropSids[2];
PTOKEN_PRIVILEGES delPrivs;
/* Functions loaded dynamically */
__CreateRestrictedToken _CreateRestrictedToken = NULL;
__IsProcessInJob _IsProcessInJob = NULL;
__CreateJobObject _CreateJobObject = NULL;
__SetInformationJobObject _SetInformationJobObject = NULL;
__AssignProcessToJobObject _AssignProcessToJobObject = NULL;
__QueryInformationJobObject _QueryInformationJobObject = NULL;
HANDLE Kernel32Handle;
HANDLE Advapi32Handle;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
@ -1802,20 +1782,6 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_ser
*/
InheritStdHandles(&si);
Advapi32Handle = LoadLibrary("ADVAPI32.DLL");
if (Advapi32Handle != NULL)
{
_CreateRestrictedToken = (__CreateRestrictedToken) (pg_funcptr_t) GetProcAddress(Advapi32Handle, "CreateRestrictedToken");
}
if (_CreateRestrictedToken == NULL)
{
/* Log error if we cannot get the function */
write_stderr(_("%s: could not locate object function to create restricted token: error code %lu\n"),
progname, (unsigned long) GetLastError());
return 0;
}
/* Open the current token to use as a base for the restricted one */
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &origToken))
{
@ -1848,19 +1814,18 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_ser
/* Error message already printed */
return 0;
b = _CreateRestrictedToken(origToken,
0,
sizeof(dropSids) / sizeof(dropSids[0]),
dropSids,
delPrivs->PrivilegeCount, delPrivs->Privileges,
0, NULL,
&restrictedToken);
b = CreateRestrictedToken(origToken,
0,
sizeof(dropSids) / sizeof(dropSids[0]),
dropSids,
delPrivs->PrivilegeCount, delPrivs->Privileges,
0, NULL,
&restrictedToken);
free(delPrivs);
FreeSid(dropSids[1].Sid);
FreeSid(dropSids[0].Sid);
CloseHandle(origToken);
FreeLibrary(Advapi32Handle);
if (!b)
{
@ -1872,79 +1837,55 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, bool as_ser
AddUserToTokenDacl(restrictedToken);
r = CreateProcessAsUser(restrictedToken, NULL, cmd, NULL, NULL, TRUE, CREATE_SUSPENDED, NULL, NULL, &si, processInfo);
Kernel32Handle = LoadLibrary("KERNEL32.DLL");
if (Kernel32Handle != NULL)
{
_IsProcessInJob = (__IsProcessInJob) (pg_funcptr_t) GetProcAddress(Kernel32Handle, "IsProcessInJob");
_CreateJobObject = (__CreateJobObject) (pg_funcptr_t) GetProcAddress(Kernel32Handle, "CreateJobObjectA");
_SetInformationJobObject = (__SetInformationJobObject) (pg_funcptr_t) GetProcAddress(Kernel32Handle, "SetInformationJobObject");
_AssignProcessToJobObject = (__AssignProcessToJobObject) (pg_funcptr_t) GetProcAddress(Kernel32Handle, "AssignProcessToJobObject");
_QueryInformationJobObject = (__QueryInformationJobObject) (pg_funcptr_t) GetProcAddress(Kernel32Handle, "QueryInformationJobObject");
}
/* Verify that we found all functions */
if (_IsProcessInJob == NULL || _CreateJobObject == NULL || _SetInformationJobObject == NULL || _AssignProcessToJobObject == NULL || _QueryInformationJobObject == NULL)
if (IsProcessInJob(processInfo->hProcess, NULL, &inJob))
{
/* Log error if we can't get version */
write_stderr(_("%s: WARNING: could not locate all job object functions in system API\n"), progname);
}
else
{
BOOL inJob;
if (_IsProcessInJob(processInfo->hProcess, NULL, &inJob))
if (!inJob)
{
if (!inJob)
{
/*
* Job objects are working, and the new process isn't in one,
* so we can create one safely. If any problems show up when
* setting it, we're going to ignore them.
*/
HANDLE job;
char jobname[128];
/*
* Job objects are working, and the new process isn't in one, so
* we can create one safely. If any problems show up when setting
* it, we're going to ignore them.
*/
HANDLE job;
char jobname[128];
sprintf(jobname, "PostgreSQL_%lu",
(unsigned long) processInfo->dwProcessId);
sprintf(jobname, "PostgreSQL_%lu",
(unsigned long) processInfo->dwProcessId);
job = _CreateJobObject(NULL, jobname);
if (job)
{
JOBOBJECT_BASIC_LIMIT_INFORMATION basicLimit;
JOBOBJECT_BASIC_UI_RESTRICTIONS uiRestrictions;
JOBOBJECT_SECURITY_LIMIT_INFORMATION securityLimit;
job = CreateJobObject(NULL, jobname);
if (job)
{
JOBOBJECT_BASIC_LIMIT_INFORMATION basicLimit;
JOBOBJECT_BASIC_UI_RESTRICTIONS uiRestrictions;
JOBOBJECT_SECURITY_LIMIT_INFORMATION securityLimit;
ZeroMemory(&basicLimit, sizeof(basicLimit));
ZeroMemory(&uiRestrictions, sizeof(uiRestrictions));
ZeroMemory(&securityLimit, sizeof(securityLimit));
ZeroMemory(&basicLimit, sizeof(basicLimit));
ZeroMemory(&uiRestrictions, sizeof(uiRestrictions));
ZeroMemory(&securityLimit, sizeof(securityLimit));
basicLimit.LimitFlags = JOB_OBJECT_LIMIT_DIE_ON_UNHANDLED_EXCEPTION | JOB_OBJECT_LIMIT_PRIORITY_CLASS;
basicLimit.PriorityClass = NORMAL_PRIORITY_CLASS;
_SetInformationJobObject(job, JobObjectBasicLimitInformation, &basicLimit, sizeof(basicLimit));
basicLimit.LimitFlags = JOB_OBJECT_LIMIT_DIE_ON_UNHANDLED_EXCEPTION | JOB_OBJECT_LIMIT_PRIORITY_CLASS;
basicLimit.PriorityClass = NORMAL_PRIORITY_CLASS;
SetInformationJobObject(job, JobObjectBasicLimitInformation, &basicLimit, sizeof(basicLimit));
uiRestrictions.UIRestrictionsClass = JOB_OBJECT_UILIMIT_DESKTOP | JOB_OBJECT_UILIMIT_DISPLAYSETTINGS |
JOB_OBJECT_UILIMIT_EXITWINDOWS | JOB_OBJECT_UILIMIT_READCLIPBOARD |
JOB_OBJECT_UILIMIT_SYSTEMPARAMETERS | JOB_OBJECT_UILIMIT_WRITECLIPBOARD;
uiRestrictions.UIRestrictionsClass = JOB_OBJECT_UILIMIT_DESKTOP | JOB_OBJECT_UILIMIT_DISPLAYSETTINGS |
JOB_OBJECT_UILIMIT_EXITWINDOWS | JOB_OBJECT_UILIMIT_READCLIPBOARD |
JOB_OBJECT_UILIMIT_SYSTEMPARAMETERS | JOB_OBJECT_UILIMIT_WRITECLIPBOARD;
_SetInformationJobObject(job, JobObjectBasicUIRestrictions, &uiRestrictions, sizeof(uiRestrictions));
SetInformationJobObject(job, JobObjectBasicUIRestrictions, &uiRestrictions, sizeof(uiRestrictions));
securityLimit.SecurityLimitFlags = JOB_OBJECT_SECURITY_NO_ADMIN | JOB_OBJECT_SECURITY_ONLY_TOKEN;
securityLimit.JobToken = restrictedToken;
_SetInformationJobObject(job, JobObjectSecurityLimitInformation, &securityLimit, sizeof(securityLimit));
securityLimit.SecurityLimitFlags = JOB_OBJECT_SECURITY_NO_ADMIN | JOB_OBJECT_SECURITY_ONLY_TOKEN;
securityLimit.JobToken = restrictedToken;
SetInformationJobObject(job, JobObjectSecurityLimitInformation, &securityLimit, sizeof(securityLimit));
_AssignProcessToJobObject(job, processInfo->hProcess);
}
AssignProcessToJobObject(job, processInfo->hProcess);
}
}
}
CloseHandle(restrictedToken);
ResumeThread(processInfo->hThread);
FreeLibrary(Kernel32Handle);
/*
* We intentionally don't close the job object handle, because we want the
* object to live on until pg_ctl shuts down.

39
src/common/restricted_token.c
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@ -28,8 +28,6 @@
/* internal vars */
char *restrict_env;
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
@ -52,36 +50,15 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo)
HANDLE restrictedToken;
SID_IDENTIFIER_AUTHORITY NtAuthority = {SECURITY_NT_AUTHORITY};
SID_AND_ATTRIBUTES dropSids[2];
__CreateRestrictedToken _CreateRestrictedToken;
HANDLE Advapi32Handle;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
Advapi32Handle = LoadLibrary("ADVAPI32.DLL");
if (Advapi32Handle == NULL)
{
pg_log_error("could not load library \"%s\": error code %lu",
"ADVAPI32.DLL", GetLastError());
return 0;
}
_CreateRestrictedToken = (__CreateRestrictedToken) (pg_funcptr_t) GetProcAddress(Advapi32Handle, "CreateRestrictedToken");
if (_CreateRestrictedToken == NULL)
{
pg_log_error("cannot create restricted tokens on this platform: error code %lu",
GetLastError());
FreeLibrary(Advapi32Handle);
return 0;
}
/* Open the current token to use as a base for the restricted one */
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &origToken))
{
pg_log_error("could not open process token: error code %lu",
GetLastError());
FreeLibrary(Advapi32Handle);
return 0;
}
@ -97,22 +74,20 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo)
pg_log_error("could not allocate SIDs: error code %lu",
GetLastError());
CloseHandle(origToken);
FreeLibrary(Advapi32Handle);
return 0;
}
b = _CreateRestrictedToken(origToken,
DISABLE_MAX_PRIVILEGE,
sizeof(dropSids) / sizeof(dropSids[0]),
dropSids,
0, NULL,
0, NULL,
&restrictedToken);
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)
{

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