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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
This commit is contained in:
Michael Paquier
2022-09-09 10:52:17 +09:00
parent df4a056619
commit 47bd0b3fa6
3 changed files with 48 additions and 159 deletions
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39
src/common/restricted_token.c
View File

@@ -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)
{