no_shm_selinux/Temp.thy
changeset 77 6f7b9039715f
child 87 8d18cfc845dd
equal deleted inserted replaced
76:f27ba31b7e96 77:6f7b9039715f
       
     1 theory Temp
       
     2 imports Static_type OS_type_def Flask_type Flask Static
       
     3 begin
       
     4 
       
     5 context tainting_s
       
     6 
       
     7 begin
       
     8 
       
     9 definition update_ss :: "t_static_state \<Rightarrow> t_sobject \<Rightarrow> t_sobject \<Rightarrow> t_static_state"
       
    10 where
       
    11   "update_ss ss so so' \<equiv> if (is_many so) then ss \<union> {so'} else (ss - {so}) \<union> {so'}"
       
    12 
       
    13 definition add_ss :: "t_static_state \<Rightarrow> t_sobject \<Rightarrow> t_static_state"
       
    14 where
       
    15   "add_ss ss so \<equiv> ss \<union> {so}"
       
    16 
       
    17 definition del_ss :: "t_static_state \<Rightarrow> t_sobject \<Rightarrow> t_static_state"
       
    18 where
       
    19   "del_ss ss so \<equiv> if (is_many so) then ss else ss - {so}"
       
    20 
       
    21 (* all reachable static states(sobjects set) *)
       
    22 inductive_set static :: "t_static_state set"
       
    23 where
       
    24   s_init:    "init_static_state \<in> static"
       
    25 | s_execve:  "\<lbrakk>ss \<in> static; S_proc (pi, pctxt, fds) tagp \<in> ss; S_file sfs tagf \<in> ss;
       
    26                (fi,fsec,pfsec,asecs) \<in> sfs; npctxt_execve pctxt fsec = Some pctxt';
       
    27                grant_execve pctxt fsec pctxt'; search_check_s pctxt (fi,fsec,pfsec,asecs) True; 
       
    28                inherit_fds_check_s pctxt' fds'; fds' \<subseteq> fds\<rbrakk>
       
    29   \<Longrightarrow> (update_ss ss (S_proc (pi, pctxt, fds) tagp) 
       
    30                     (S_proc (pi, pctxt', fds') (tagp \<or> tagf))) \<in> static"
       
    31 | s_clone:   "\<lbrakk>ss \<in> static; S_proc (pi, pctxt, fds) tagp \<in> ss; 
       
    32                permission_check pctxt pctxt C_process P_fork;
       
    33                inherit_fds_check_s pctxt fds'; fds' \<subseteq> fds\<rbrakk>
       
    34   \<Longrightarrow> (add_ss ss (S_proc (Created, pctxt, fds') tagp)) \<in> static"
       
    35 (*
       
    36 | s_kill:    "\<lbrakk>ss \<in> static; S_proc (pi, pctxt, fds) tagp \<in> ss; 
       
    37                S_proc (pi', pctxt', fds') tagp' \<in> ss; 
       
    38                permission_check pctxt pctxt' C_process P_sigkill\<rbrakk>
       
    39   \<Longrightarrow> (del_ss ss (S_proc (pi', pctxt', fds', shms') tagp')) \<in> static"
       
    40 *)
       
    41 | s_ptrace:  "\<lbrakk>ss \<in> static; S_proc sp False \<in> ss; S_proc sp' True \<in> ss; 
       
    42                permission_check (sextxt_of_sproc sp) (sectxt_of_sproc sp') C_process P_ptrace\<rbrakk>
       
    43   \<Longrightarrow> (update_ss ss (S_proc sp False) (S_proc sp True)) \<in> static"
       
    44 | s_ptrace': "\<lbrakk>ss \<in> static; S_proc sp True \<in> ss; S_proc sp' False \<in> ss; 
       
    45                permission_check (sextxt_of_sproc sp) (sectxt_of_sproc sp') C_process P_ptrace\<rbrakk>
       
    46   \<Longrightarrow> (update_ss ss (S_proc sp' False) (S_proc sp' True)) \<in> static"
       
    47 (*
       
    48 | s_exit:    "\<lbrakk>ss \<in> static; S_proc sp tagp \<in> ss\<rbrakk> \<Longrightarrow> (del_ss ss (S_proc sp tagp)) \<in> static"
       
    49 *)
       
    50 | s_open:    "\<lbrakk>ss \<in> static; S_proc (pi, pctxt, fds) tagp \<in> ss; S_file sfs tagf \<in> ss; sf \<in> sfs;
       
    51               search_check_s pctxt sf True; \<not> is_creat_excl_flag flags; 
       
    52               oflags_check flags pctxt (sectxt_of_sfile sf); permission_check pctxt pctxt C_fd P_setattr\<rbrakk>
       
    53   \<Longrightarrow> (update_ss ss (S_proc (pi, pctxt, fds) tagp)
       
    54                     (S_proc (pi, pctxt, fds \<union> {(pctxt,flags,sf)}) tagp)) \<in> static"
       
    55 | s_open':   "\<lbrakk>ss \<in> static; S_proc (pi, pctxt, fds) tagp \<in> ss; is_creat_excl_flag flags;
       
    56                S_dir (pfi,fsec,pfsec,asecs) \<in> ss; search_check_s pctxt (pfi,fsec,pfsec,asecs) False; 
       
    57                nfsec = nfctxt_create pctxt fsec C_file; oflags_check flags pctxt nfsec;
       
    58                permission_check pctxt fsec C_dir P_add_rename; permission_check pctxt pctxt C_fd P_setattr\<rbrakk>
       
    59   \<Longrightarrow> (update_ss (add_ss ss (S_file {(Created, nfsec, Some fsec, asecs \<union> {fsec})} tagp))
       
    60          (S_proc (pi, pctxt, fds) tagp)
       
    61          (S_proc (pi, pctxt, fds \<union> {(pctxt, flags, (Created, nfsec, Some fsec, asecs \<union> {fsec}))}) tagp)
       
    62       ) \<in> static"
       
    63 | S_readf:   "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) False \<in> ss; (fdctxt,flags,sf) \<in> fds; 
       
    64                permission_check pctxt fdctxt C_fd P_setattr; S_file sfs True \<in> ss; sf \<in> sfs;
       
    65                permission_check pctxt (sectxt_of_sfile sf) C_file P_read; is_read_flag flags\<rbrakk>
       
    66   \<Longrightarrow> (update_ss ss (S_proc (pi, pctxt,fds) False) (S_proc (pi, pctxt, fds) True)) \<in> static"
       
    67 | S_writef:  "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) True \<in> ss; (fdctxt,flags,sf) \<in> fds; 
       
    68                permission_check pctxt fdctxt C_fd P_setattr; sf \<in> sfs; S_file sfs False \<in> ss; 
       
    69                permission_check pctxt (sectxt_of_sfile sf) C_file P_write; is_write_flag flags\<rbrakk>
       
    70   \<Longrightarrow> (update_ss ss (S_file sfs False) (S_file sfs True)) \<in> static"
       
    71 (*
       
    72 | S_unlink:  "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds,shms) tagp \<in> ss; S_file sfs tagf \<in> ss;  
       
    73                (Init f,fsec,Some pfsec,asecs) \<in> sfs; 
       
    74                search_check_s pctxt (Init f,fsec,Some pfsec,asecs) True; 
       
    75                permission_check pctxt fsec C_file P_unlink; 
       
    76                permission_check pctxt pfsec C_dir P_remove_name\<rbrakk>
       
    77   \<Longrightarrow> ((ss - {S_file sfs tagf}) \<union> {S_file (sfs - {(Init f,fsec,Some pfsec,asecs)}) tagf}) \<in> static"
       
    78 | S_rmdir:   "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds,shms) tagp \<in> ss; 
       
    79                S_dir (fi,fsec,Some pfsec,asecs) \<in> ss;  
       
    80                search_check_s pctxt (fi,fsec,Some pfsec,asecs) False; 
       
    81                permission_check pctxt fsec C_dir P_rmdir;
       
    82                permission_check pctxt pfsec C_dir P_remove_name\<rbrakk>
       
    83   \<Longrightarrow> (del_ss ss (S_dir (fi,fsec,Some pfsec,asecs))) \<in> static"
       
    84 *)
       
    85 | S_mkdir:   "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_dir (fi,fsec,pfsec,asecs) \<in> ss;  
       
    86                search_check_s pctxt (fi,fsec,pfsec,asecs) False; 
       
    87                permission_check pctxt (nfctxt_create pctxt fsec C_dir) C_dir P_create;
       
    88                permission_check pctxt fsec C_dir P_add_name\<rbrakk>
       
    89   \<Longrightarrow> (add_ss ss (S_dir (Created,nfctxt_create pctxt fsec C_dir,Some fsec,asecs \<union> {fsec}))) \<in> static"
       
    90 | s_link:    "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_dir (pfi,pfsec,ppfsec,asecs) \<in> ss;
       
    91                S_file sfs tagf \<in> ss; sf \<in> sfs; nfsec = nfctxt_create pctxt pfsec C_file;  
       
    92                search_check_s pctxt (pfi,pfsec,ppfsec,asecs) False; search_check_s pctxt sf True;
       
    93                permission_check pctxt (sectxt_of_sfile sf) C_file P_link; 
       
    94                permission_check pctxt pfsec C_dir P_add_name\<rbrakk>
       
    95   \<Longrightarrow> (update_ss ss (S_file sfs tagf) 
       
    96                   (S_file (sfs \<union> {(Created,nfsec,Some pfsec, asecs \<union> {pfsec})}) tagf)) \<in> static"
       
    97 | s_trunc:   "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) True \<in> ss; S_file sfs False \<in> ss; sf \<in> sfs; 
       
    98                search_check_s pctxt sf True; permission_check pctxt (sectxt_of_sfile sf) C_file P_setattr\<rbrakk>
       
    99   \<Longrightarrow> (update_ss ss (S_file sfs False) (S_file sfs True)) \<in> static"
       
   100 (*
       
   101 | s_rename:  "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_file sfs tagf \<in> ss;
       
   102                (sf#spf') \<in> sfs; S_dir spf tagpf \<in> ss; \<not>((sf#spf') \<preceq> (sf#spf)); 
       
   103                search_check_s pctxt spf False; search_check_s pctxt (sf#spf') True; 
       
   104                sectxt_of_sfile (sf#spf') = Some fctxt; sectxt_of_sfile spf = Some pfctxt;  
       
   105                permission_check pctxt fctxt C_file P_rename;
       
   106                permission_check pctxt pfctxt C_dir P_add_name;
       
   107                ss_rename ss (sf#spf') (sf#spf) ss'; 
       
   108                ss_rename_no_same_fname ss (sf#spf') (sf#spf)\<rbrakk>
       
   109               \<Longrightarrow> ss' \<in> static"
       
   110 | s_rename': "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_dir (sf#spf') tagf \<in> ss;
       
   111                S_dir spf tagpf \<in> ss; \<not>((sf#spf') \<preceq> (sf#spf)); 
       
   112                search_check_s pctxt spf False; search_check_s pctxt (sf#spf') True; 
       
   113                sectxt_of_sfile (sf#spf') = Some fctxt; sectxt_of_sfile spf = Some pfctxt;  
       
   114                permission_check pctxt fctxt C_dir P_reparent;
       
   115                permission_check pctxt pfctxt C_dir P_add_name;
       
   116                ss_rename ss (sf#spf') (sf#spf) ss'; 
       
   117                ss_rename_no_same_fname ss (sf#spf') (sf#spf)\<rbrakk>
       
   118               \<Longrightarrow> ss' \<in> static"
       
   119 *)
       
   120 | s_createq: "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; 
       
   121                permission_check pctxt pctxt C_msgq P_associate;
       
   122                permission_check pctxt pctxt C_msgq P_create\<rbrakk>
       
   123   \<Longrightarrow> (add_ss ss (S_msgq (Created,pctxt,[]))) \<in> static" 
       
   124 | s_sendmsg: "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_msgq (qi,qctxt,sms) \<in> ss;
       
   125                permission_check pctxt qctxt C_msgq P_enqueue;
       
   126                permission_check pctxt qctxt C_msgq P_write; 
       
   127                permission_check pctxt pctxt C_msg  P_create\<rbrakk>
       
   128   \<Longrightarrow> (update_ss ss (S_msgq (qi,qctxt,sms)) 
       
   129                     (S_msgq (qi,qctxt,sms @ [(Created, pctxt, tagp)]))) \<in> static"
       
   130 | s_recvmsg: "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; 
       
   131                S_msgq (qi,qctxt,(mi,mctxt,tagm)#sms) \<in> ss;
       
   132                permission_check pctxt qctxt C_msgq P_read; 
       
   133                permission_check pctxt mctxt C_msg  P_receive\<rbrakk>
       
   134   \<Longrightarrow> (update_ss (update_ss ss (S_proc (pi,pctxt,fds) tagp) (S_proc (pi, pctxt, fds) (tagp \<or> tagm))) 
       
   135                  (S_msgq (qi, qctxt, (mi, mctxt, tagm)#sms))
       
   136                  (S_msgq (qi, qctxt, sms))) \<in> static"
       
   137 (*
       
   138 | s_removeq: "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_msgq (qi,qctxt,sms) \<in> ss;
       
   139                permission_check pctxt qctxt C_msgq P_destroy\<rbrakk>
       
   140   \<Longrightarrow> (del_ss ss (S_msgq (qi,qctxt,sms))) \<in> static"
       
   141 | s_createh: "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss;
       
   142                permission_check pctxt pctxt C_shm P_associate; 
       
   143                permission_check pctxt pctxt C_shm P_create\<rbrakk>
       
   144    \<Longrightarrow> (add_ss ss (S_shm (Created, pctxt))) \<in> static"
       
   145 | s_attach:  "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_shm (hi,hctxt) \<in> ss;
       
   146                if flag = SHM_RDONLY then permission_check pctxt hctxt C_shm P_read
       
   147                else (permission_check pctxt hctxt C_shm P_read \<and>
       
   148                      permission_check pctxt hctxt C_shm P_write)\<rbrakk>
       
   149    \<Longrightarrow> (update_ss ss (S_proc (pi,pctxt,fds) tagp)
       
   150                     (S_proc (pi,pctxt,fds,shms \<union> {((hi,hctxt),flag)}) tagp)) \<in> static"
       
   151 | s_detach:  "\<lbrakk>ss \<in> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_shm sh \<in> ss;
       
   152                (sh,flag) \<in> shms; \<not> is_many_sshm sh\<rbrakk>
       
   153    \<Longrightarrow> (update_ss ss (S_proc (pi,pctxt,fds) tagp)
       
   154                     (S_proc (pi,pctxt,fds,shms - {(sh,flag)}) tagp)) \<in> static"
       
   155 | s_deleteh: "\<lbrakk>ss \<notin> static; S_proc (pi,pctxt,fds) tagp \<in> ss; S_shm (hi,hctxt) \<in> ss;
       
   156                permission_check pctxt hctxt C_shm P_destroy; \<not> is_many_sshm sh\<rbrakk>
       
   157    \<Longrightarrow> (remove_sproc_sshm (del_ss ss (S_shm (hi,hctxt))) (hi,hctxt)) \<in> static"
       
   158 *)
       
   159 
       
   160 fun tainted_s :: "t_static_state \<Rightarrow> t_sobject \<Rightarrow> bool"
       
   161 where
       
   162   "tainted_s ss (S_proc sp  tag) = (S_proc sp tag  \<in> ss \<and> tag = True)"
       
   163 | "tainted_s ss (S_file sfs tag) = (S_file sfs tag \<in> ss \<and> tag = True)"
       
   164 (*
       
   165 | "tainted_s ss (S_msg  (qi, sec, sms)  (mi, secm, tag)) = 
       
   166      (S_msgq (qi, sec, sms) \<in> ss \<and> (mi,secm,tag) \<in> set sms \<and> tag = True)"
       
   167 *)
       
   168 | "tainted_s ss _ = False"
       
   169 
       
   170 (*
       
   171 fun tainted_s :: "t_object \<Rightarrow> t_static_state \<Rightarrow> bool"
       
   172 where 
       
   173   "tainted_s (O_proc p)  ss = (\<exists> sp. S_proc sp True \<in> ss \<and> sproc_related p sp)"
       
   174 | "tainted_s (O_file f)  ss = (\<exists> sfs sf. S_file sfs True \<in> ss \<and> sf \<in> sfs \<and> sfile_related f sf)"
       
   175 | "tainted_s (O_msg q m) ss = (\<exists> sq. S_msgq sq \<in> ss \<and> smsgq_smsg_relatainted q m sq)"
       
   176 | "tainted_s _           ss = False"
       
   177 *)
       
   178 
       
   179 definition taintable_s :: "t_object \<Rightarrow> bool"
       
   180 where
       
   181   "taintable_s obj \<equiv> \<exists> ss \<in> static. \<exists> sobj. tainted_s ss sobj \<and> init_obj_related sobj obj"
       
   182 
       
   183 (* this definition is wrong, cause process can exited from static-world 
       
   184 definition deletable_s :: "t_object \<Rightarrow> bool"
       
   185 where
       
   186   "deletable_s obj \<equiv> init_alive obj \<and> (\<exists> ss \<in> static. \<forall> sobj \<in> ss. \<not> init_obj_related sobj obj)"
       
   187 *)
       
   188 
       
   189 lemma ss_init_sp_unique_initstate:
       
   190   "\<lbrakk>S_proc (Init p, pctxt, fds) tagp \<in> init_static_state;
       
   191     S_proc (Init p, pctxt', fds') tagp' \<in> init_static_state\<rbrakk>
       
   192    \<Longrightarrow> pctxt' = pctxt \<and> fds' = fds \<and> tagp' = tagp"
       
   193 apply (simp add:init_static_state_def)
       
   194 apply (erule exE|erule conjE)+
       
   195 apply (case_tac obj, case_tac [!] obja)
       
   196 apply (auto simp:init_cp2sproc_def split:option.splits)
       
   197 done
       
   198 
       
   199 (*
       
   200 lemma ss_init_sp_unique:
       
   201   "ss \<in> static \<Longrightarrow> \<forall> p pctxt fds tagp pctxt' fds' tagp'. S_proc (Init p, pctxt, fds) tagp \<in> ss 
       
   202       \<and> S_proc (Init p, pctxt', fds') tagp' \<in> ss \<longrightarrow> pctxt' = pctxt \<and> fds' = fds \<and> tagp' = tagp"
       
   203 apply (erule static.induct)
       
   204 apply (rule allI|rule impI|erule conjE)+
       
   205 apply (erule ss_init_sp_unique_initstate, simp)
       
   206 sorry
       
   207 
       
   208 lemma taintable_s_imp_init_alive_aux[rule_format]:
       
   209   "ss \<in> static \<Longrightarrow> \<forall> sobj obj. sobj \<in> ss \<and> init_obj_related sobj obj \<longrightarrow> init_alive obj"
       
   210 apply (erule static.induct)
       
   211 apply (clarsimp simp:init_static_state_def)
       
   212 apply (case_tac obj, simp)
       
   213 sorry
       
   214 
       
   215 lemma taintable_s_imp_init_alive:
       
   216   "taintable_s obj \<Longrightarrow> init_alive obj"
       
   217 apply (clarsimp simp add:taintable_s_def)
       
   218 thm taintable_s_imp_init_alive_aux
       
   219 apply (erule_tac sobj = sobj in taintable_s_imp_init_alive_aux)
       
   220 apply (case_tac sobj)
       
   221 apply simp_all
       
   222 apply (case_tac [!] obj)
       
   223 apply ( simp_all)
       
   224 apply (case_tac bool, simp, simp)
       
   225 apply (case_tac bool, simp+)
       
   226 done
       
   227 *)
       
   228 
       
   229 fun deleted_s :: "t_static_state \<Rightarrow> t_object \<Rightarrow> bool"
       
   230 where
       
   231   "deleted_s ss (O_proc p) = (\<exists> pi pctxt fds tagp pctxt' fds' tagp'. S_proc (pi, pctxt, fds) tagp \<in> ss \<and>
       
   232      S_proc (Init p, pctxt', fds') tagp' \<in> ss \<and> pi \<noteq> Init p \<and> permission_check pctxt pctxt' C_process P_sigkill)"
       
   233 | "deleted_s ss (O_file f) = (\<exists> pi pctxt fds tagp sfs tagf fsec pfsec asecs. S_proc (pi, pctxt, fds) tagp \<in> ss \<and>
       
   234      S_file sfs tagf \<in> ss \<and> (Init f, fsec, Some pfsec, asecs) \<in> sfs \<and> 
       
   235      search_check_s pctxt (Init f, fsec, Some pfsec, asecs) True \<and>
       
   236      permission_check pctxt fsec C_file P_unlink \<and>
       
   237      permission_check pctxt pfsec C_dir P_remove_name)"
       
   238 | "deleted_s ss (O_dir f) = (\<exists> pi pctxt fds tagp fsec pfsec asecs. S_proc (pi, pctxt, fds) tagp \<in> ss \<and>
       
   239      S_dir (Init f, fsec, Some pfsec, asecs) \<in> ss \<and> search_check_s pctxt (Init f, fsec, Some pfsec, asecs) False \<and>
       
   240      permission_check pctxt fsec C_dir P_rmdir \<and> permission_check pctxt pfsec C_dir P_remove_name)"
       
   241 | "deleted_s ss (O_msgq q) = (\<exists> pi pctxt fds tagp qctxt sms. S_proc (pi, pctxt, fds) tagp \<in> ss \<and>
       
   242      S_msgq (Init q, qctxt, sms) \<in> ss \<and> permission_check pctxt qctxt C_msgq P_destroy)"
       
   243 
       
   244 definition deletable_s :: "t_object \<Rightarrow> bool"
       
   245 where
       
   246   "deletable_s obj \<equiv> init_alive obj \<and> (\<exists> ss \<in> static. deleted_s ss obj)"
       
   247 
       
   248 definition undeletable_s :: "t_object \<Rightarrow> bool"
       
   249 where
       
   250   "undeletable_s obj \<equiv> init_alive obj \<and> (\<forall> ss \<in> static. \<not> deleted_s ss obj)"
       
   251 
       
   252 definition init_ss_eq:: "t_static_state \<Rightarrow> t_static_state \<Rightarrow> bool" (infix "\<doteq>" 100)
       
   253 where
       
   254   "ss \<doteq> ss' \<equiv> ss \<subseteq> ss' \<and> {sobj. is_init_sobj sobj \<and> sobj \<in> ss'} \<subseteq> ss"
       
   255 
       
   256 lemma [simp]: "ss \<doteq> ss"
       
   257 by (auto simp:init_ss_eq_def)
       
   258 
       
   259 definition init_ss_in:: "t_static_state \<Rightarrow> t_static_state set \<Rightarrow> bool" (infix "\<propto>" 101)
       
   260 where
       
   261   "ss \<propto> sss \<equiv> \<exists> ss' \<in> sss. ss \<doteq> ss'"
       
   262 
       
   263 lemma s2ss_included_sobj:
       
   264   "\<lbrakk>alive s obj; co2sobj s obj= Some sobj\<rbrakk> \<Longrightarrow> sobj \<in> (s2ss s)"
       
   265 by (simp add:s2ss_def, rule_tac x = obj in exI, simp)
       
   266 
       
   267 lemma init_ss_in_prop:
       
   268   "\<lbrakk>s2ss s \<propto> static; co2sobj s obj = Some sobj; alive s obj; init_obj_related sobj obj\<rbrakk>
       
   269    \<Longrightarrow> \<exists> ss \<in> static. sobj \<in> ss"
       
   270 apply (simp add:init_ss_in_def init_ss_eq_def)
       
   271 apply (erule bexE, erule conjE)
       
   272 apply (rule_tac x = ss' in bexI, auto dest!:s2ss_included_sobj)
       
   273 done
       
   274 
       
   275 
       
   276 end
       
   277 
       
   278 end