windows/winsecur.c

   1 /*
   2  * winsecur.c: implementation of winsecur.h.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7
   8 #include "putty.h"
   9
  10 #if !defined NO_SECURITY
  11
  12 #define WINSECUR_GLOBAL
  13 #include "winsecur.h"
  14
  15 int got_advapi(void)
  16 {
  17     static int attempted = FALSE;
  18     static int successful;
  19     static HMODULE advapi;
  20
  21     if (!attempted) {
  22         attempted = TRUE;
  23         advapi = load_system32_dll("advapi32.dll");
  24         successful = advapi &&
  25             GET_WINDOWS_FUNCTION(advapi, GetSecurityInfo) &&
  26             GET_WINDOWS_FUNCTION(advapi, OpenProcessToken) &&
  27             GET_WINDOWS_FUNCTION(advapi, GetTokenInformation) &&
  28             GET_WINDOWS_FUNCTION(advapi, InitializeSecurityDescriptor) &&
  29             GET_WINDOWS_FUNCTION(advapi, SetSecurityDescriptorOwner) &&
  30             GET_WINDOWS_FUNCTION(advapi, SetEntriesInAclA);
  31     }
  32     return successful;
  33 }
  34
  35 int got_crypt(void)
  36 {
  37     static int attempted = FALSE;
  38     static int successful;
  39     static HMODULE crypt;
  40
  41     if (!attempted) {
  42         attempted = TRUE;
  43         crypt = load_system32_dll("crypt32.dll");
  44         successful = crypt &&
  45             GET_WINDOWS_FUNCTION(crypt, CryptProtectMemory);
  46     }
  47     return successful;
  48 }
  49
  50 PSID get_user_sid(void)
  51 {
  52     HANDLE proc = NULL, tok = NULL;
  53     TOKEN_USER *user = NULL;
  54     DWORD toklen, sidlen;
  55     PSID sid = NULL, ret = NULL;
  56
  57     if (!got_advapi())
  58         goto cleanup;
  59
  60     if ((proc = OpenProcess(MAXIMUM_ALLOWED, FALSE,
  61                             GetCurrentProcessId())) == NULL)
  62         goto cleanup;
  63
  64     if (!p_OpenProcessToken(proc, TOKEN_QUERY, &tok))
  65         goto cleanup;
  66
  67     if (!p_GetTokenInformation(tok, TokenUser, NULL, 0, &toklen) &&
  68         GetLastError() != ERROR_INSUFFICIENT_BUFFER)
  69         goto cleanup;
  70
  71     if ((user = (TOKEN_USER *)LocalAlloc(LPTR, toklen)) == NULL)
  72         goto cleanup;
  73
  74     if (!p_GetTokenInformation(tok, TokenUser, user, toklen, &toklen))
  75         goto cleanup;
  76
  77     sidlen = GetLengthSid(user->User.Sid);
  78
  79     sid = (PSID)smalloc(sidlen);
  80
  81     if (!CopySid(sidlen, sid, user->User.Sid))
  82         goto cleanup;
  83
  84     /* Success. Move sid into the return value slot, and null it out
  85      * to stop the cleanup code freeing it. */
  86     ret = sid;
  87     sid = NULL;
  88
  89   cleanup:
  90     if (proc != NULL)
  91         CloseHandle(proc);
  92     if (tok != NULL)
  93         CloseHandle(tok);
  94     if (user != NULL)
  95         LocalFree(user);
  96     if (sid != NULL)
  97         sfree(sid);
  98
  99     return ret;
 100 }
 101
 102 int make_private_security_descriptor(DWORD permissions,
 103                                      PSECURITY_DESCRIPTOR *psd,
 104                                      PSID *networksid,
 105                                      PACL *acl,
 106                                      char **error)
 107 {
 108     SID_IDENTIFIER_AUTHORITY nt_auth = SECURITY_NT_AUTHORITY;
 109     EXPLICIT_ACCESS ea[3];
 110     int acl_err;
 111     int ret = FALSE;
 112
 113     *psd = NULL;
 114     *networksid = NULL;
 115     *acl = NULL;
 116     *error = NULL;
 117
 118     if (!got_advapi()) {
 119         *error = dupprintf("unable to load advapi32.dll");
 120         goto cleanup;
 121     }
 122
 123     if (!AllocateAndInitializeSid(&nt_auth, 1, SECURITY_NETWORK_RID,
 124                                   0, 0, 0, 0, 0, 0, 0, networksid)) {
 125         *error = dupprintf("unable to construct SID for "
 126                            "local same-user access only: %s",
 127                            win_strerror(GetLastError()));
 128         goto cleanup;
 129     }
 130
 131     memset(ea, 0, sizeof(ea));
 132     ea[0].grfAccessPermissions = permissions;
 133     ea[0].grfAccessMode = REVOKE_ACCESS;
 134     ea[0].grfInheritance = NO_INHERITANCE;
 135     ea[0].Trustee.TrusteeForm = TRUSTEE_IS_NAME;
 136     ea[0].Trustee.ptstrName = "EVERYONE";
 137     ea[1].grfAccessPermissions = permissions;
 138     ea[1].grfAccessMode = GRANT_ACCESS;
 139     ea[1].grfInheritance = NO_INHERITANCE;
 140     ea[1].Trustee.TrusteeForm = TRUSTEE_IS_NAME;
 141     ea[1].Trustee.ptstrName = "CURRENT_USER";
 142     ea[2].grfAccessPermissions = permissions;
 143     ea[2].grfAccessMode = REVOKE_ACCESS;
 144     ea[2].grfInheritance = NO_INHERITANCE;
 145     ea[2].Trustee.TrusteeForm = TRUSTEE_IS_SID;
 146     ea[2].Trustee.ptstrName = (LPTSTR)*networksid;
 147
 148     acl_err = p_SetEntriesInAclA(3, ea, NULL, acl);
 149     if (acl_err != ERROR_SUCCESS || *acl == NULL) {
 150         *error = dupprintf("unable to construct ACL: %s",
 151                            win_strerror(acl_err));
 152         goto cleanup;
 153     }
 154
 155     *psd = (PSECURITY_DESCRIPTOR)
 156         LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
 157     if (!*psd) {
 158         *error = dupprintf("unable to allocate security descriptor: %s",
 159                            win_strerror(GetLastError()));
 160         goto cleanup;
 161     }
 162
 163     if (!InitializeSecurityDescriptor(*psd, SECURITY_DESCRIPTOR_REVISION)) {
 164         *error = dupprintf("unable to initialise security descriptor: %s",
 165                            win_strerror(GetLastError()));
 166         goto cleanup;
 167     }
 168
 169     if (!SetSecurityDescriptorDacl(*psd, TRUE, *acl, FALSE)) {
 170         *error = dupprintf("unable to set DACL in security descriptor: %s",
 171                            win_strerror(GetLastError()));
 172         goto cleanup;
 173     }
 174
 175     ret = TRUE;
 176
 177   cleanup:
 178     if (!ret) {
 179         if (*psd) {
 180             LocalFree(*psd);
 181             *psd = NULL;
 182         }
 183         if (*networksid) {
 184             LocalFree(*networksid);
 185             *networksid = NULL;
 186         }
 187         if (*acl) {
 188             LocalFree(*acl);
 189             *acl = NULL;
 190         }
 191     } else {
 192         sfree(*error);
 193         *error = NULL;
 194     }
 195     return ret;
 196 }
 197
 198 #endif /* !defined NO_SECURITY */