*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/port/exec.c,v 1.57 2008/01/01 19:46:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/port/exec.c,v 1.58 2008/02/29 15:31:33 mha Exp $
*
*-------------------------------------------------------------------------
*/
static int resolve_symlinks(char *path);
static char *pipe_read_line(char *cmd, char *line, int maxsize);
+#ifdef WIN32
+static BOOL GetUserSid(PSID * ppSidUser, HANDLE hToken);
+#endif
/*
* validate_exec -- validate "path" as an executable file
putenv(strdup(env_path));
}
}
+
+#ifdef WIN32
+
+/*
+ * AddUserToDacl(HANDLE hProcess)
+ *
+ * This function adds the current user account to the default DACL
+ * which gets attached to the restricted token used when we create
+ * a restricted process.
+ *
+ * This is required because of some security changes in Windows
+ * that appeared in patches to XP/2K3 and in Vista/2008.
+ *
+ * On these machines, the Administrator account is not included in
+ * the default DACL - you just get Administrators + System. For
+ * regular users you get User + System. Because we strip Administrators
+ * when we create the restricted token, we are left with only System
+ * in the DACL which leads to access denied errors for later CreatePipe()
+ * and CreateProcess() calls when running as Administrator.
+ *
+ * This function fixes this problem by modifying the DACL of the
+ * specified process and explicitly re-adding the current user account.
+ * This is still secure because the Administrator account inherits it's
+ * privileges from the Administrators group - it doesn't have any of
+ * it's own.
+ */
+BOOL
+AddUserToDacl(HANDLE hProcess)
+{
+ int i;
+ ACL_SIZE_INFORMATION asi;
+ ACCESS_ALLOWED_ACE *pace;
+ DWORD dwNewAclSize;
+ DWORD dwSize = 0;
+ DWORD dwTokenInfoLength = 0;
+ DWORD dwResult = 0;
+ HANDLE hToken = NULL;
+ PACL pacl = NULL;
+ PSID psidUser = NULL;
+ TOKEN_DEFAULT_DACL tddNew;
+ TOKEN_DEFAULT_DACL *ptdd = NULL;
+ TOKEN_INFORMATION_CLASS tic = TokenDefaultDacl;
+ BOOL ret = FALSE;
+
+ /* Get the token for the process */
+ if (!OpenProcessToken(hProcess, TOKEN_QUERY | TOKEN_ADJUST_DEFAULT, &hToken))
+ {
+ log_error("could not open process token: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ /* Figure out the buffer size for the DACL info */
+ if (!GetTokenInformation(hToken, tic, (LPVOID) NULL, dwTokenInfoLength, &dwSize))
+ {
+ if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+ {
+ ptdd = (TOKEN_DEFAULT_DACL *) LocalAlloc(LPTR, dwSize);
+ if (ptdd == NULL)
+ {
+ log_error("could not allocate %i bytes of memory", dwSize);
+ goto cleanup;
+ }
+
+ if (!GetTokenInformation(hToken, tic, (LPVOID) ptdd, dwSize, &dwSize))
+ {
+ log_error("could not get token information: %ui", GetLastError());
+ goto cleanup;
+ }
+ }
+ else
+ {
+ log_error("could not get token information buffer size: %ui", GetLastError());
+ goto cleanup;
+ }
+ }
+
+ /* Get the ACL info */
+ if (!GetAclInformation(ptdd->DefaultDacl, (LPVOID) & asi,
+ (DWORD) sizeof(ACL_SIZE_INFORMATION),
+ AclSizeInformation))
+ {
+ log_error("could not get ACL information: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ /* Get the SID for the current user. We need to add this to the ACL. */
+ if (!GetUserSid(&psidUser, hToken))
+ {
+ log_error("could not get user SID: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ /* Figure out the size of the new ACL */
+ dwNewAclSize = asi.AclBytesInUse + sizeof(ACCESS_ALLOWED_ACE) + GetLengthSid(psidUser) - sizeof(DWORD);
+
+ /* Allocate the ACL buffer & initialize it */
+ pacl = (PACL) LocalAlloc(LPTR, dwNewAclSize);
+ if (pacl == NULL)
+ {
+ log_error("could not allocate %i bytes of memory", dwNewAclSize);
+ goto cleanup;
+ }
+
+ if (!InitializeAcl(pacl, dwNewAclSize, ACL_REVISION))
+ {
+ log_error("could not initialize ACL: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ /* Loop through the existing ACEs, and build the new ACL */
+ for (i = 0; i < (int) asi.AceCount; i++)
+ {
+ if (!GetAce(ptdd->DefaultDacl, i, (LPVOID *) & pace))
+ {
+ log_error("could not get ACE: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ if (!AddAce(pacl, ACL_REVISION, MAXDWORD, pace, ((PACE_HEADER) pace)->AceSize))
+ {
+ log_error("could not add ACE: %ui", GetLastError());
+ goto cleanup;
+ }
+ }
+
+ /* Add the new ACE for the current user */
+ if (!AddAccessAllowedAce(pacl, ACL_REVISION, GENERIC_ALL, psidUser))
+ {
+ log_error("could not add access allowed ACE: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ /* Set the new DACL in the token */
+ tddNew.DefaultDacl = pacl;
+
+ if (!SetTokenInformation(hToken, tic, (LPVOID) & tddNew, dwNewAclSize))
+ {
+ log_error("could not set token information: %ui", GetLastError());
+ goto cleanup;
+ }
+
+ ret = TRUE;
+
+cleanup:
+ if (psidUser)
+ FreeSid(psidUser);
+
+ if (pacl)
+ LocalFree((HLOCAL) pacl);
+
+ if (ptdd)
+ LocalFree((HLOCAL) ptdd);
+
+ if (hToken)
+ CloseHandle(hToken);
+
+ return ret;
+}
+
+/*
+ * GetUserSid*PSID *ppSidUser, HANDLE hToken)
+ *
+ * Get the SID for the current user
+ */
+static BOOL
+GetUserSid(PSID * ppSidUser, HANDLE hToken)
+{
+ DWORD dwLength;
+ DWORD cbName = 250;
+ DWORD cbDomainName = 250;
+ PTOKEN_USER pTokenUser = NULL;
+
+
+ if (!GetTokenInformation(hToken,
+ TokenUser,
+ pTokenUser,
+ 0,
+ &dwLength))
+ {
+ if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+ {
+ pTokenUser = (PTOKEN_USER) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwLength);
+
+ if (pTokenUser == NULL)
+ {
+ log_error("could not allocate %ui bytes of memory", dwLength);
+ return FALSE;
+ }
+ }
+ else
+ {
+ log_error("could not get token information buffer size: %ui", GetLastError());
+ return FALSE;
+ }
+ }
+
+ if (!GetTokenInformation(hToken,
+ TokenUser,
+ pTokenUser,
+ dwLength,
+ &dwLength))
+ {
+ HeapFree(GetProcessHeap(), 0, pTokenUser);
+ pTokenUser = NULL;
+
+ log_error("could not get token information: %ui", GetLastError());
+ return FALSE;
+ }
+
+ *ppSidUser = pTokenUser->User.Sid;
+ return TRUE;
+}
+
+#endif
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