749 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			749 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C++
		
	
	
	
| /* security.cc: NT file access control functions
 | |
| 
 | |
|    Originaly written by Gunther Ebert, gunther.ebert@ixos-leipzig.de
 | |
|    Completely rewritten by Corinna Vinschen <corinna@vinschen.de>
 | |
| 
 | |
| This file is part of Cygwin.
 | |
| 
 | |
| This software is a copyrighted work licensed under the terms of the
 | |
| Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
 | |
| details. */
 | |
| 
 | |
| #include "winsup.h"
 | |
| #include <unistd.h>
 | |
| #include <stdlib.h>
 | |
| #include <cygwin/acl.h>
 | |
| #include "cygerrno.h"
 | |
| #include "security.h"
 | |
| #include "path.h"
 | |
| #include "fhandler.h"
 | |
| #include "dtable.h"
 | |
| #include "pinfo.h"
 | |
| #include "cygheap.h"
 | |
| #include "ntdll.h"
 | |
| #include "tls_pbuf.h"
 | |
| #include <aclapi.h>
 | |
| 
 | |
| #define ALL_SECURITY_INFORMATION (DACL_SECURITY_INFORMATION \
 | |
| 				  | GROUP_SECURITY_INFORMATION \
 | |
| 				  | OWNER_SECURITY_INFORMATION)
 | |
| 
 | |
| static GENERIC_MAPPING NO_COPY_RO file_mapping = { FILE_GENERIC_READ,
 | |
| 						   FILE_GENERIC_WRITE,
 | |
| 						   FILE_GENERIC_EXECUTE,
 | |
| 						   FILE_ALL_ACCESS };
 | |
| LONG
 | |
| get_file_sd (HANDLE fh, path_conv &pc, security_descriptor &sd,
 | |
| 	     bool justcreated)
 | |
| {
 | |
|   NTSTATUS status = STATUS_SUCCESS;
 | |
|   OBJECT_ATTRIBUTES attr;
 | |
|   IO_STATUS_BLOCK io;
 | |
|   ULONG len = SD_MAXIMUM_SIZE, rlen;
 | |
| 
 | |
|   /* Allocate space for the security descriptor. */
 | |
|   if (!sd.malloc (len))
 | |
|     {
 | |
|       set_errno (ENOMEM);
 | |
|       return -1;
 | |
|     }
 | |
|   /* Try to fetch the security descriptor if the handle is valid. */
 | |
|   if (fh)
 | |
|     {
 | |
|       status = NtQuerySecurityObject (fh, ALL_SECURITY_INFORMATION,
 | |
| 				      sd, len, &rlen);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	debug_printf ("NtQuerySecurityObject (%S), status %y",
 | |
| 		      pc.get_nt_native_path (), status);
 | |
|     }
 | |
|   /* If the handle was NULL, or fetching with the original handle didn't work,
 | |
|      try to reopen the file with READ_CONTROL and fetch the security descriptor
 | |
|      using that handle. */
 | |
|   if (!fh || !NT_SUCCESS (status))
 | |
|     {
 | |
|       status = NtOpenFile (&fh, READ_CONTROL,
 | |
| 			   fh ? pc.init_reopen_attr (attr, fh)
 | |
| 			      : pc.get_object_attr (attr, sec_none_nih),
 | |
| 			   &io, FILE_SHARE_VALID_FLAGS,
 | |
| 			   FILE_OPEN_FOR_BACKUP_INTENT
 | |
| 			   | pc.is_known_reparse_point ()
 | |
| 			   ? FILE_OPEN_REPARSE_POINT : 0);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	{
 | |
| 	  sd.free ();
 | |
| 	  __seterrno_from_nt_status (status);
 | |
| 	  return -1;
 | |
| 	}
 | |
|       status = NtQuerySecurityObject (fh, ALL_SECURITY_INFORMATION,
 | |
| 				      sd, len, &rlen);
 | |
|       NtClose (fh);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	{
 | |
| 	  sd.free ();
 | |
| 	  __seterrno_from_nt_status (status);
 | |
| 	  return -1;
 | |
| 	}
 | |
|     }
 | |
|   /* We have a security descriptor now.  Unfortunately, if you want to know
 | |
|      if an ACE is inherited from the parent object, this isn't sufficient.
 | |
| 
 | |
|      In the simple case, the SDs control word contains one of the
 | |
|      SE_DACL_AUTO_INHERITED or SE_DACL_PROTECTED flags, or at least one of
 | |
|      the ACEs has the INHERITED_ACE flag set.  In all of these cases we
 | |
|      know the DACL has been inherited.
 | |
| 
 | |
|      If none of these flags is set in the SD, the information whether
 | |
|      or not an ACE has been inherited is not available in the DACL of the
 | |
|      object.  In this case GetSecurityInfo fetches the SD from the parent
 | |
|      directory and tests if the object's SD contains inherited ACEs from the
 | |
|      parent.
 | |
| 
 | |
|      Note that we're not testing the SE_DACL_AUTO_INHERITED and
 | |
|      SE_DACL_PROTECTED flags here because we know the state the file's SD
 | |
|      is in.  Since we're creating all files with a NULL descriptor, the DACL
 | |
|      is either inherited from the parent, or it's the default DACL.  In
 | |
|      neither case, one of these flags is set.
 | |
| 
 | |
|      For speed, we're not calling RtlConvertToAutoInheritSecurityObject
 | |
|      anymore (but keep the code here for reference).  Rather we just test
 | |
|      if one of the parent's ACEs is inheritable.  If so, we know we inherited
 | |
|      it and set the SE_DACL_AUTO_INHERITED flag.  If not, we may assume our
 | |
|      object's DACL is the default DACL.
 | |
| 
 | |
|      This functionality is slow and the extra information is only required
 | |
|      when the file has been created and the permissions are about to be set
 | |
|      to POSIX permissions.  Therefore we only use it in case the file just
 | |
|      got created. */
 | |
|   if (justcreated)
 | |
|     {
 | |
|       PACL dacl;
 | |
|       BOOLEAN exists, def;
 | |
|       ACCESS_ALLOWED_ACE *ace;
 | |
|       UNICODE_STRING dirname;
 | |
|       PSECURITY_DESCRIPTOR psd;
 | |
|       tmp_pathbuf tp;
 | |
| 
 | |
|       /* Open the parent directory with READ_CONTROL... */
 | |
|       RtlSplitUnicodePath (pc.get_nt_native_path (), &dirname, NULL);
 | |
|       InitializeObjectAttributes (&attr, &dirname, pc.objcaseinsensitive (),
 | |
| 				  NULL, NULL);
 | |
|       status = NtOpenFile (&fh, READ_CONTROL, &attr, &io,
 | |
| 			   FILE_SHARE_VALID_FLAGS,
 | |
| 			   FILE_OPEN_FOR_BACKUP_INTENT
 | |
| 			   | FILE_OPEN_REPARSE_POINT);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	{
 | |
| 	  debug_printf ("NtOpenFile (%S), status %y", &dirname, status);
 | |
| 	  return 0;
 | |
| 	}
 | |
|       /* ... fetch the parent's security descriptor ... */
 | |
|       psd = (PSECURITY_DESCRIPTOR) tp.w_get ();
 | |
|       status = NtQuerySecurityObject (fh, ALL_SECURITY_INFORMATION,
 | |
| 				      psd, len, &rlen);
 | |
|       NtClose (fh);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	{
 | |
| 	  debug_printf ("NtQuerySecurityObject (%S), status %y",
 | |
| 			&dirname, status);
 | |
| 	  return 0;
 | |
| 	}
 | |
| #if 0
 | |
|       /* ... and create a new security descriptor in which all inherited ACEs
 | |
| 	 are marked with the INHERITED_ACE flag.  For a description of the
 | |
| 	 undocumented RtlConvertToAutoInheritSecurityObject function from
 | |
| 	 ntdll.dll see the MSDN man page for the advapi32 function
 | |
| 	 ConvertToAutoInheritPrivateObjectSecurity.  Fortunately the latter
 | |
| 	 is just a shim. */
 | |
|       PSECURITY_DESCRIPTOR nsd;
 | |
|       status = RtlConvertToAutoInheritSecurityObject (psd, sd, &nsd, NULL,
 | |
| 						      pc.isdir (),
 | |
| 						      &file_mapping);
 | |
|       if (!NT_SUCCESS (status))
 | |
| 	{
 | |
| 	  debug_printf ("RtlConvertToAutoInheritSecurityObject (%S), status %y",
 | |
| 			&dirname, status);
 | |
| 	  return 0;
 | |
| 	}
 | |
|       /* Eventually copy the new security descriptor into sd and delete the
 | |
| 	 original one created by RtlConvertToAutoInheritSecurityObject from
 | |
| 	 the heap. */
 | |
|       len = RtlLengthSecurityDescriptor (nsd);
 | |
|       memcpy ((PSECURITY_DESCRIPTOR) sd, nsd, len);
 | |
|       RtlDeleteSecurityObject (&nsd);
 | |
| #else
 | |
|       /* ... and check the parent descriptor for inheritable ACEs matching
 | |
| 	 our current object type (file/dir).  The simple truth in our case
 | |
| 	 is, either the parent dir had inheritable ACEs and all our ACEs are
 | |
| 	 inherited, or the parent dir didn't have inheritable ACEs and all
 | |
| 	 our ACEs are taken from the default DACL. */
 | |
|       bool inherited = false;
 | |
|       BYTE search_flags = pc.isdir () ? SUB_CONTAINERS_AND_OBJECTS_INHERIT
 | |
| 				      : SUB_OBJECTS_ONLY_INHERIT;
 | |
|       if (NT_SUCCESS (RtlGetDaclSecurityDescriptor (psd, &exists, &dacl, &def))
 | |
| 	  && exists && dacl)
 | |
| 	for (ULONG idx = 0; idx < dacl->AceCount; ++idx)
 | |
| 	  if (NT_SUCCESS (RtlGetAce (dacl, idx, (PVOID *) &ace))
 | |
| 	      && (ace->Header.AceFlags & search_flags))
 | |
| 	    {
 | |
| 	      inherited = true;
 | |
| 	      break;
 | |
| 	    }
 | |
|       /* Then, if the parent descriptor contained inheritable ACEs, we mark
 | |
| 	 the SD as SE_DACL_AUTO_INHERITED.  Note that this requires the
 | |
| 	 matching check in get_posix_access.  If we ever revert to
 | |
| 	 RtlConvertToAutoInheritSecurityObject, the check in get_posix_access
 | |
| 	 has to test every single ACE for the INHERITED_ACE flag again. */
 | |
|       if (inherited
 | |
| 	  && NT_SUCCESS (RtlGetDaclSecurityDescriptor (sd, &exists, &dacl,
 | |
| 						       &def))
 | |
| 	  && exists && dacl)
 | |
| 	RtlSetControlSecurityDescriptor (sd, SE_DACL_AUTO_INHERITED,
 | |
| 					     SE_DACL_AUTO_INHERITED);
 | |
| #endif
 | |
|     }
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| LONG
 | |
| set_file_sd (HANDLE fh, path_conv &pc, security_descriptor &sd, bool is_chown)
 | |
| {
 | |
|   NTSTATUS status = STATUS_SUCCESS;
 | |
|   int retry = 0;
 | |
|   int res = -1;
 | |
| 
 | |
|   for (; retry < 2; ++retry)
 | |
|     {
 | |
|       if (fh)
 | |
| 	{
 | |
| 	  status = NtSetSecurityObject (fh,
 | |
| 					is_chown ? ALL_SECURITY_INFORMATION
 | |
| 						 : DACL_SECURITY_INFORMATION,
 | |
| 					sd);
 | |
| 	  if (NT_SUCCESS (status))
 | |
| 	    {
 | |
| 	      res = 0;
 | |
| 	      break;
 | |
| 	    }
 | |
| 	}
 | |
|       if (!retry)
 | |
| 	{
 | |
| 	  OBJECT_ATTRIBUTES attr;
 | |
| 	  IO_STATUS_BLOCK io;
 | |
| 	  status = NtOpenFile (&fh, (is_chown ? WRITE_OWNER  : 0) | WRITE_DAC,
 | |
| 			       fh ? pc.init_reopen_attr (attr, fh)
 | |
| 				  : pc.get_object_attr (attr, sec_none_nih),
 | |
| 			       &io,
 | |
| 			       FILE_SHARE_VALID_FLAGS,
 | |
| 			       FILE_OPEN_FOR_BACKUP_INTENT
 | |
| 			       | pc.is_known_reparse_point ()
 | |
| 			       ? FILE_OPEN_REPARSE_POINT : 0);
 | |
| 	  if (!NT_SUCCESS (status))
 | |
| 	    {
 | |
| 	      fh = NULL;
 | |
| 	      break;
 | |
| 	    }
 | |
| 	}
 | |
|     }
 | |
|   if (retry && fh)
 | |
|     NtClose (fh);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     __seterrno_from_nt_status (status);
 | |
|   return res;
 | |
| }
 | |
| 
 | |
| static int
 | |
| get_reg_sd (HANDLE handle, security_descriptor &sd_ret)
 | |
| {
 | |
|   LONG ret;
 | |
|   DWORD len = 0;
 | |
| 
 | |
|   ret = RegGetKeySecurity ((HKEY) handle, ALL_SECURITY_INFORMATION,
 | |
| 			   sd_ret, &len);
 | |
|   if (ret == ERROR_INSUFFICIENT_BUFFER)
 | |
|     {
 | |
|       if (!sd_ret.malloc (len))
 | |
| 	set_errno (ENOMEM);
 | |
|       else
 | |
| 	ret = RegGetKeySecurity ((HKEY) handle, ALL_SECURITY_INFORMATION,
 | |
| 				 sd_ret, &len);
 | |
|     }
 | |
|   if (ret != ERROR_SUCCESS)
 | |
|     {
 | |
|       __seterrno ();
 | |
|       return -1;
 | |
|     }
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| int
 | |
| get_reg_attribute (HKEY hkey, mode_t *attribute, uid_t *uidret,
 | |
| 		   gid_t *gidret)
 | |
| {
 | |
|   security_descriptor sd;
 | |
| 
 | |
|   if (!get_reg_sd (hkey, sd))
 | |
|     {
 | |
|       get_posix_access (sd, attribute, uidret, gidret, NULL, 0);
 | |
|       return 0;
 | |
|     }
 | |
|   /* The entries are already set to default values */
 | |
|   return -1;
 | |
| }
 | |
| 
 | |
| int
 | |
| get_file_attribute (HANDLE handle, path_conv &pc,
 | |
| 		    mode_t *attribute, uid_t *uidret, gid_t *gidret)
 | |
| {
 | |
|   if (pc.has_acls ())
 | |
|     {
 | |
|       security_descriptor sd;
 | |
| 
 | |
|       if (!get_file_sd (handle, pc, sd, false))
 | |
| 	{
 | |
| 	  get_posix_access (sd, attribute, uidret, gidret, NULL, 0);
 | |
| 	  return 0;
 | |
| 	}
 | |
|       /* ENOSYS is returned by get_file_sd if fetching the DACL from a remote
 | |
| 	 share returns STATUS_INVALID_NETWORK_RESPONSE, which in turn is
 | |
| 	 converted to ERROR_BAD_NET_RESP.  This potentially occurs when trying
 | |
| 	 to fetch DACLs from a NT4 machine which is not part of the domain of
 | |
| 	 the requesting machine. */
 | |
|       else if (get_errno () != ENOSYS)
 | |
| 	{
 | |
| 	  if (uidret)
 | |
| 	    *uidret = ILLEGAL_UID;
 | |
| 	  if (gidret)
 | |
| 	    *gidret = ILLEGAL_GID;
 | |
| 
 | |
| 	  return -1;
 | |
| 	}
 | |
|     }
 | |
| 
 | |
|   if (uidret)
 | |
|     *uidret = myself->uid;
 | |
|   if (gidret)
 | |
|     *gidret = myself->gid;
 | |
| 
 | |
|   return -1;
 | |
| }
 | |
| 
 | |
| bool
 | |
| add_access_allowed_ace (PACL acl, DWORD attributes, PSID sid, size_t &len_add,
 | |
| 			DWORD inherit)
 | |
| {
 | |
|   NTSTATUS status = RtlAddAccessAllowedAceEx (acl, ACL_REVISION, inherit,
 | |
| 					      attributes, sid);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     {
 | |
|       __seterrno_from_nt_status (status);
 | |
|       return false;
 | |
|     }
 | |
|   len_add += sizeof (ACCESS_ALLOWED_ACE) - sizeof (DWORD) + RtlLengthSid (sid);
 | |
|   return true;
 | |
| }
 | |
| 
 | |
| bool
 | |
| add_access_denied_ace (PACL acl, DWORD attributes, PSID sid, size_t &len_add,
 | |
| 		       DWORD inherit)
 | |
| {
 | |
|   NTSTATUS status = RtlAddAccessDeniedAceEx (acl, ACL_REVISION, inherit,
 | |
| 					     attributes, sid);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     {
 | |
|       __seterrno_from_nt_status (status);
 | |
|       return false;
 | |
|     }
 | |
|   len_add += sizeof (ACCESS_DENIED_ACE) - sizeof (DWORD) + RtlLengthSid (sid);
 | |
|   return true;
 | |
| }
 | |
| 
 | |
| void
 | |
| set_security_attribute (path_conv &pc, int attribute, PSECURITY_ATTRIBUTES psa,
 | |
| 			security_descriptor &sd)
 | |
| {
 | |
|   psa->lpSecurityDescriptor = sd.malloc (SECURITY_DESCRIPTOR_MIN_LENGTH);
 | |
|   RtlCreateSecurityDescriptor ((PSECURITY_DESCRIPTOR) psa->lpSecurityDescriptor,
 | |
| 				SECURITY_DESCRIPTOR_REVISION);
 | |
|   psa->lpSecurityDescriptor = set_posix_access (attribute, geteuid32 (),
 | |
| 						getegid32 (), NULL, 0,
 | |
| 						sd, false);
 | |
| }
 | |
| 
 | |
| int
 | |
| get_object_sd (HANDLE handle, security_descriptor &sd)
 | |
| {
 | |
|   ULONG len = 0;
 | |
|   NTSTATUS status;
 | |
| 
 | |
|   status = NtQuerySecurityObject (handle, ALL_SECURITY_INFORMATION,
 | |
| 				  sd, len, &len);
 | |
|   if (status != STATUS_BUFFER_TOO_SMALL)
 | |
|     {
 | |
|       __seterrno_from_nt_status (status);
 | |
|       return -1;
 | |
|     }
 | |
|   if (!sd.malloc (len))
 | |
|     {
 | |
|       set_errno (ENOMEM);
 | |
|       return -1;
 | |
|     }
 | |
|   status = NtQuerySecurityObject (handle, ALL_SECURITY_INFORMATION,
 | |
| 				  sd, len, &len);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     {
 | |
|       __seterrno_from_nt_status (status);
 | |
|       return -1;
 | |
|     }
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| int
 | |
| get_object_attribute (HANDLE handle, uid_t *uidret, gid_t *gidret,
 | |
| 		      mode_t *attribute)
 | |
| {
 | |
|   security_descriptor sd;
 | |
| 
 | |
|   if (get_object_sd (handle, sd))
 | |
|     return -1;
 | |
|   return get_posix_access (sd, attribute, uidret, gidret, NULL, 0)
 | |
| 	 >= 0 ? 0 : -1;
 | |
| }
 | |
| 
 | |
| int
 | |
| create_object_sd_from_attribute (uid_t uid, gid_t gid, mode_t attribute,
 | |
| 				 security_descriptor &sd)
 | |
| {
 | |
|   return set_posix_access (attribute, uid, gid, NULL, 0, sd, false)
 | |
| 	 ? 0 : -1;
 | |
| }
 | |
| 
 | |
| int
 | |
| set_object_sd (HANDLE handle, security_descriptor &sd, bool chown)
 | |
| {
 | |
|   NTSTATUS status;
 | |
|   status = NtSetSecurityObject (handle, chown ? ALL_SECURITY_INFORMATION
 | |
| 					      : DACL_SECURITY_INFORMATION, sd);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     {
 | |
|       __seterrno_from_nt_status (status);
 | |
|       return -1;
 | |
|     }
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| int
 | |
| set_object_attribute (HANDLE handle, uid_t uid, gid_t gid, mode_t attribute)
 | |
| {
 | |
|   security_descriptor sd;
 | |
| 
 | |
|   if (create_object_sd_from_attribute (uid, gid, attribute, sd)
 | |
|       || set_object_sd (handle, sd, uid != ILLEGAL_UID || gid != ILLEGAL_GID))
 | |
|     return -1;
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| int
 | |
| set_created_file_access (HANDLE handle, path_conv &pc, mode_t attr)
 | |
| {
 | |
|   int ret = -1;
 | |
|   security_descriptor sd, sd_ret;
 | |
|   mode_t attr_rd;
 | |
|   uid_t uid;
 | |
|   gid_t gid;
 | |
|   tmp_pathbuf tp;
 | |
|   aclent_t *aclp;
 | |
|   int nentries, idx;
 | |
|   bool std_acl;
 | |
| 
 | |
|   if (!get_file_sd (handle, pc, sd, true))
 | |
|     {
 | |
|       attr |= S_JUSTCREATED;
 | |
|       if (pc.isdir ())
 | |
| 	attr |= S_IFDIR;
 | |
|       attr_rd = attr;
 | |
|       aclp = (aclent_t *) tp.c_get ();
 | |
|       if ((nentries = get_posix_access (sd, &attr_rd, &uid, &gid, aclp,
 | |
| 					MAX_ACL_ENTRIES, &std_acl)) >= 0)
 | |
| 	{
 | |
| 	  if (S_ISLNK (attr))
 | |
| 	    {
 | |
| 	      /* Symlinks always get the request POSIX perms. */
 | |
| 	      aclp[0].a_perm = (attr >> 6) & S_IRWXO;
 | |
| 	      if ((idx = searchace (aclp, nentries, GROUP_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm = (attr >> 3) & S_IRWXO;
 | |
| 	      if ((idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm = (attr >> 3) & S_IRWXO;
 | |
| 	      if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm = attr & S_IRWXO;
 | |
| 	    }
 | |
| 	  else
 | |
| 	    {
 | |
| 	      /* Overwrite ACL permissions as required by POSIX 1003.1e
 | |
| 		 draft 17. */
 | |
| 	      aclp[0].a_perm &= (attr >> 6) & S_IRWXO;
 | |
| 	      if ((idx = searchace (aclp, nentries, CLASS_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm &= (attr >> 3) & S_IRWXO;
 | |
| 	      if (std_acl
 | |
| 		  && (idx = searchace (aclp, nentries, GROUP_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm &= (attr >> 3) & S_IRWXO;
 | |
| 	      if ((idx = searchace (aclp, nentries, OTHER_OBJ)) >= 0)
 | |
| 		aclp[idx].a_perm &= attr & S_IRWXO;
 | |
| 	    }
 | |
| 	  /* Construct appropriate inherit attribute for new directories.
 | |
| 	     Basically we do this only for the sake of non-Cygwin applications.
 | |
| 	     Cygwin applications don't need these.  Additionally, if the
 | |
| 	     S_ISGID bit is set, propagate it. */
 | |
| 	  if (S_ISDIR (attr))
 | |
| 	    {
 | |
| 	      if (searchace (aclp, nentries, DEF_USER_OBJ) < 0)
 | |
| 		{
 | |
| 		  aclp[nentries].a_type = DEF_USER_OBJ;
 | |
| 		  aclp[nentries].a_id = ILLEGAL_UID;
 | |
| 		  aclp[nentries++].a_perm = (attr >> 6) & S_IRWXO;
 | |
| 		}
 | |
| 	      if (searchace (aclp, nentries, DEF_GROUP_OBJ) < 0)
 | |
| 		{
 | |
| 		  aclp[nentries].a_type = DEF_GROUP_OBJ;
 | |
| 		  aclp[nentries].a_id = ILLEGAL_GID;
 | |
| 		  aclp[nentries++].a_perm = (attr >> 3) & S_IRWXO;
 | |
| 		}
 | |
| 	      if (searchace (aclp, nentries, DEF_OTHER_OBJ) < 0)
 | |
| 		{
 | |
| 		  aclp[nentries].a_type = DEF_OTHER_OBJ;
 | |
| 		  aclp[nentries].a_id = ILLEGAL_UID;
 | |
| 		  aclp[nentries++].a_perm = attr & S_IRWXO;
 | |
| 		}
 | |
| 	      if (attr_rd & S_ISGID)
 | |
| 		attr |= S_ISGID;
 | |
| 	    }
 | |
| 	  if (set_posix_access (attr, uid, gid, aclp, nentries, sd_ret,
 | |
| 				pc.fs_is_samba ()))
 | |
| 	    ret = set_file_sd (handle, pc, sd_ret, attr_rd & S_ISGID);
 | |
| 	}
 | |
|     }
 | |
|   return ret;
 | |
| }
 | |
| 
 | |
| static int
 | |
| check_access (security_descriptor &sd, GENERIC_MAPPING &mapping,
 | |
| 	      ACCESS_MASK desired, int flags, bool effective)
 | |
| {
 | |
|   int ret = -1;
 | |
|   NTSTATUS status, allow;
 | |
|   ACCESS_MASK granted;
 | |
|   DWORD plen = sizeof (PRIVILEGE_SET) + 3 * sizeof (LUID_AND_ATTRIBUTES);
 | |
|   PPRIVILEGE_SET pset = (PPRIVILEGE_SET) alloca (plen);
 | |
|   HANDLE tok = ((effective && cygheap->user.issetuid ())
 | |
| 		? cygheap->user.imp_token ()
 | |
| 		: hProcImpToken);
 | |
| 
 | |
|   if (!tok)
 | |
|     {
 | |
|       if (!DuplicateTokenEx (hProcToken, MAXIMUM_ALLOWED, NULL,
 | |
| 			    SecurityImpersonation, TokenImpersonation,
 | |
| 			    &hProcImpToken))
 | |
| 	 {
 | |
| 	    __seterrno ();
 | |
| 	    return ret;
 | |
| 	 }
 | |
|       tok = hProcImpToken;
 | |
|     }
 | |
| 
 | |
|   status = NtAccessCheck (sd, tok, desired, &mapping, pset, &plen, &granted,
 | |
| 			  &allow);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     __seterrno ();
 | |
|   else if (!NT_SUCCESS (allow))
 | |
|     {
 | |
|       /* CV, 2006-10-16: Now, that's really weird.  Imagine a user who has no
 | |
| 	 standard access to a file, but who has backup and restore privileges
 | |
| 	 and these privileges are enabled in the access token.  One would
 | |
| 	 expect that the AccessCheck function takes this into consideration
 | |
| 	 when returning the access status.  Otherwise, why bother with the
 | |
| 	 pset parameter, right?
 | |
| 	 But not so.  AccessCheck actually returns a status of "false" here,
 | |
| 	 even though opening a file with backup resp. restore intent
 | |
| 	 naturally succeeds for this user.  This definitely spoils the results
 | |
| 	 of access(2) for administrative users or the SYSTEM account.  So, in
 | |
| 	 case the access check fails, another check against the user's
 | |
| 	 backup/restore privileges has to be made.  Sigh. */
 | |
|       int granted_flags = 0;
 | |
|       BOOLEAN has_priv;
 | |
| 
 | |
|       if (flags & R_OK)
 | |
| 	{
 | |
| 	  pset->PrivilegeCount = 1;
 | |
| 	  pset->Control = 0;
 | |
| 	  pset->Privilege[0].Luid.HighPart = 0L;
 | |
| 	  pset->Privilege[0].Luid.LowPart = SE_BACKUP_PRIVILEGE;
 | |
| 	  pset->Privilege[0].Attributes = 0;
 | |
| 	  status = NtPrivilegeCheck (tok, pset, &has_priv);
 | |
| 	  if (NT_SUCCESS (status) && has_priv)
 | |
| 	    granted_flags |= R_OK;
 | |
| 	}
 | |
|       if (flags & W_OK)
 | |
| 	{
 | |
| 	  pset->PrivilegeCount = 1;
 | |
| 	  pset->Control = 0;
 | |
| 	  pset->Privilege[0].Luid.HighPart = 0L;
 | |
| 	  pset->Privilege[0].Luid.LowPart = SE_RESTORE_PRIVILEGE;
 | |
| 	  pset->Privilege[0].Attributes = 0;
 | |
| 	  status = NtPrivilegeCheck (tok, pset, &has_priv);
 | |
| 	  if (NT_SUCCESS (status) && has_priv)
 | |
| 	    granted_flags |= W_OK;
 | |
| 	}
 | |
|       if (granted_flags == flags)
 | |
| 	ret = 0;
 | |
|       else
 | |
| 	set_errno (EACCES);
 | |
|     }
 | |
|   else
 | |
|     ret = 0;
 | |
|   return ret;
 | |
| }
 | |
| 
 | |
| /* Samba override.  Check security descriptor for Samba UNIX user and group
 | |
|    accounts and check if we have an RFC 2307 mapping to a Windows account.
 | |
|    Create a new security descriptor with all of the UNIX accounts with
 | |
|    valid mapping replaced with their Windows counterpart. */
 | |
| static void
 | |
| convert_samba_sd (security_descriptor &sd_ret)
 | |
| {
 | |
|   NTSTATUS status;
 | |
|   BOOLEAN dummy;
 | |
|   PSID sid;
 | |
|   cygsid owner;
 | |
|   cygsid group;
 | |
|   SECURITY_DESCRIPTOR sd;
 | |
|   cyg_ldap cldap;
 | |
|   tmp_pathbuf tp;
 | |
|   PACL acl, oacl;
 | |
|   size_t acl_len;
 | |
|   PACCESS_ALLOWED_ACE ace;
 | |
| 
 | |
|   if (!NT_SUCCESS (RtlGetOwnerSecurityDescriptor (sd_ret, &sid, &dummy)))
 | |
|     return;
 | |
|   owner = sid;
 | |
|   if (!NT_SUCCESS (RtlGetGroupSecurityDescriptor (sd_ret, &sid, &dummy)))
 | |
|     return;
 | |
|   group = sid;
 | |
| 
 | |
|   if (sid_id_auth (owner) == 22)
 | |
|     {
 | |
|       struct passwd *pwd;
 | |
|       uid_t uid = owner.get_uid (&cldap);
 | |
|       if (uid < UNIX_POSIX_OFFSET && (pwd = internal_getpwuid (uid)))
 | |
| 	owner.getfrompw (pwd);
 | |
|     }
 | |
|   if (sid_id_auth (group) == 22)
 | |
|     {
 | |
|       struct group *grp;
 | |
|       gid_t gid = group.get_gid (&cldap);
 | |
|       if (gid < UNIX_POSIX_OFFSET && (grp = internal_getgrgid (gid)))
 | |
| 	group.getfromgr (grp);
 | |
|     }
 | |
| 
 | |
|   if (!NT_SUCCESS (RtlGetDaclSecurityDescriptor (sd_ret, &dummy,
 | |
| 						 &oacl, &dummy)))
 | |
|     return;
 | |
|   acl = (PACL) tp.w_get ();
 | |
|   RtlCreateAcl (acl, ACL_MAXIMUM_SIZE, ACL_REVISION);
 | |
|   acl_len = sizeof (ACL);
 | |
| 
 | |
|   for (DWORD i = 0; i < oacl->AceCount; ++i)
 | |
|     if (NT_SUCCESS (RtlGetAce (oacl, i, (PVOID *) &ace)))
 | |
|       {
 | |
| 	cygsid ace_sid ((PSID) &ace->SidStart);
 | |
| 	if (sid_id_auth (ace_sid) == 22)
 | |
| 	  {
 | |
| 	    if (sid_sub_auth (ace_sid, 0) == 1) /* user */
 | |
| 	      {
 | |
| 		struct passwd *pwd;
 | |
| 		uid_t uid = ace_sid.get_uid (&cldap);
 | |
| 		if (uid < UNIX_POSIX_OFFSET && (pwd = internal_getpwuid (uid)))
 | |
| 		  ace_sid.getfrompw (pwd);
 | |
| 	      }
 | |
| 	    else if (sid_sub_auth (ace_sid, 0) == 2) /* group */
 | |
| 	      {
 | |
| 		struct group *grp;
 | |
| 		gid_t gid = ace_sid.get_gid (&cldap);
 | |
| 		if (gid < UNIX_POSIX_OFFSET && (grp = internal_getgrgid (gid)))
 | |
| 		  ace_sid.getfromgr (grp);
 | |
| 	      }
 | |
| 	  }
 | |
| 	if (!add_access_allowed_ace (acl, ace->Mask, ace_sid, acl_len,
 | |
| 				     ace->Header.AceFlags))
 | |
| 	  return;
 | |
|       }
 | |
|   acl->AclSize = acl_len;
 | |
| 
 | |
|   RtlCreateSecurityDescriptor (&sd, SECURITY_DESCRIPTOR_REVISION);
 | |
|   RtlSetControlSecurityDescriptor (&sd, SE_DACL_PROTECTED, SE_DACL_PROTECTED);
 | |
|   RtlSetOwnerSecurityDescriptor (&sd, owner, FALSE);
 | |
|   RtlSetGroupSecurityDescriptor (&sd, group, FALSE);
 | |
| 
 | |
|   status = RtlSetDaclSecurityDescriptor (&sd, TRUE, acl, FALSE);
 | |
|   if (!NT_SUCCESS (status))
 | |
|     return;
 | |
|   DWORD sd_size = 0;
 | |
|   status = RtlAbsoluteToSelfRelativeSD (&sd, sd_ret, &sd_size);
 | |
|   if (sd_size > 0 && sd_ret.malloc (sd_size))
 | |
|     RtlAbsoluteToSelfRelativeSD (&sd, sd_ret, &sd_size);
 | |
| }
 | |
| 
 | |
| int
 | |
| check_file_access (path_conv &pc, int flags, bool effective)
 | |
| {
 | |
|   security_descriptor sd;
 | |
|   int ret = -1;
 | |
|   ACCESS_MASK desired = 0;
 | |
|   if (flags & R_OK)
 | |
|     desired |= FILE_READ_DATA;
 | |
|   if (flags & W_OK)
 | |
|     desired |= FILE_WRITE_DATA;
 | |
|   if (flags & X_OK)
 | |
|     desired |= FILE_EXECUTE;
 | |
|   if (!get_file_sd (pc.handle (), pc, sd, false))
 | |
|     {
 | |
|       /* Tweak Samba security descriptor as necessary. */
 | |
|       if (pc.fs_is_samba ())
 | |
| 	convert_samba_sd (sd);
 | |
|       ret = check_access (sd, file_mapping, desired, flags, effective);
 | |
|     }
 | |
|   debug_printf ("flags %y, ret %d", flags, ret);
 | |
|   return ret;
 | |
| }
 | |
| 
 | |
| int
 | |
| check_registry_access (HANDLE hdl, int flags, bool effective)
 | |
| {
 | |
|   security_descriptor sd;
 | |
|   int ret = -1;
 | |
|   static GENERIC_MAPPING NO_COPY_RO reg_mapping = { KEY_READ,
 | |
| 						    KEY_WRITE,
 | |
| 						    KEY_EXECUTE,
 | |
| 						    KEY_ALL_ACCESS };
 | |
|   ACCESS_MASK desired = 0;
 | |
|   if (flags & R_OK)
 | |
|     desired |= KEY_ENUMERATE_SUB_KEYS;
 | |
|   if (flags & W_OK)
 | |
|     desired |= KEY_SET_VALUE;
 | |
|   if (flags & X_OK)
 | |
|     desired |= KEY_QUERY_VALUE;
 | |
| 
 | |
|   if ((HKEY) hdl == HKEY_PERFORMANCE_DATA)
 | |
|     /* RegGetKeySecurity() always fails with ERROR_INVALID_HANDLE.  */
 | |
|     ret = 0;
 | |
|   else if (!get_reg_sd (hdl, sd))
 | |
|     ret = check_access (sd, reg_mapping, desired, flags, effective);
 | |
| 
 | |
|   /* As long as we can't write the registry... */
 | |
|   if (flags & W_OK)
 | |
|     {
 | |
|       set_errno (EROFS);
 | |
|       ret = -1;
 | |
|     }
 | |
|   debug_printf ("flags %y, ret %d", flags, ret);
 | |
|   return ret;
 | |
| }
 |