I have a question in a corner case.
How do we handle the case when filename component contains whitespaces?
Or multibyte characters?
Rught now, policy_scan.l of checkpolicy defines IDENTIFIER element as follows:
{letter}({alnum}|[_\-])*([\.]?({alnum}|[_\-]))* { return(IDENTIFIER); }
I think it is an issue in corner case, however, to be considered.
IMO, it is not a good idea to handle multibyte support by ourselves.
The security policy should have same character set with other stuffs.
Regarding to whitespaces, is it possible to define a syntax without conflicts
to the existing syntax?
Thanks,
--
NEC Europe Ltd, Global Competence Center
KaiGai Kohei <kohei.kaigai@xxxxxxxxxx>
> -----Original Message-----
> From: owner-selinux@xxxxxxxxxxxxx [mailto:owner-selinux@xxxxxxxxxxxxx] On
> Behalf Of Eric Paris
> Sent: 28. MÃrz 2011 19:00
> To: selinux@xxxxxxxxxxxxx
> Cc: method@xxxxxxxxxxxxxxx; sds@xxxxxxxxxxxxx
> Subject: [PATCH] checkpolicy: add support for using last path component in
> type transition rules
>
> This patch adds support for using the last path component as part of the
> information in making labeling decisions for new objects. A example
> rule looks like so:
>
> type_transition unconfined_t etc_t:file system_conf_t eric;
>
> This rule says if unconfined_t creates a file in a directory labeled
> etc_t and the last path component is "eric" (no globbing, no matching
> magic, just exact strcmp) it should be labeled system_conf_t.
>
> The kernel and policy representation does not have support for such
> rules in conditionals, and thus policy explicitly notes that fact if
> such a rule is added to a conditional.
>
> Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
> ---
>
> diff -up checkpolicy-2.0.23/module_compiler.c.eparis2
> checkpolicy-2.0.23/module_compiler.c
> --- checkpolicy-2.0.23/module_compiler.c.eparis2 2010-12-21
> 16:35:45.000000000 -0500
> +++ checkpolicy-2.0.23/module_compiler.c 2011-03-23 14:19:51.152530839
> -0400
> @@ -1313,6 +1313,18 @@ void append_role_allow(role_allow_rule_t
> }
>
> /* this doesn't actually append, but really prepends it */
> +void append_filename_trans(filename_trans_rule_t * filename_trans_rules)
> +{
> + avrule_decl_t *decl = stack_top->decl;
> +
> + /* filename transitions are not allowed within conditionals */
> + assert(stack_top->type == 1);
> +
> + filename_trans_rules->next = decl->filename_trans_rules;
> + decl->filename_trans_rules = filename_trans_rules;
> +}
> +
> +/* this doesn't actually append, but really prepends it */
> void append_range_trans(range_trans_rule_t * range_tr_rules)
> {
> avrule_decl_t *decl = stack_top->decl;
> diff -up checkpolicy-2.0.23/module_compiler.h.eparis2
> checkpolicy-2.0.23/module_compiler.h
> --- checkpolicy-2.0.23/module_compiler.h.eparis2 2010-12-21
> 16:35:45.000000000 -0500
> +++ checkpolicy-2.0.23/module_compiler.h 2011-03-23 14:19:51.154531123
> -0400
> @@ -80,6 +80,7 @@ void append_avrule(avrule_t * avrule);
> void append_role_trans(role_trans_rule_t * role_tr_rules);
> void append_role_allow(role_allow_rule_t * role_allow_rules);
> void append_range_trans(range_trans_rule_t * range_tr_rules);
> +void append_filename_trans(filename_trans_rule_t * filename_trans_rules);
>
> /* Create a new optional block and add it to the global policy.
> * During the second pass resolve the block's requirements. Return 0
> diff -up checkpolicy-2.0.23/policy_define.c.eparis2
> checkpolicy-2.0.23/policy_define.c
> --- checkpolicy-2.0.23/policy_define.c.eparis2 2010-12-21
> 16:35:45.000000000 -0500
> +++ checkpolicy-2.0.23/policy_define.c 2011-03-28 13:50:57.667710915
> -0400
> @@ -2196,6 +2196,190 @@ int define_role_allow(void)
> return 0;
> }
>
> +avrule_t *define_cond_filename_trans(void)
> +{
> + yyerror("type transitions with a filename not allowed inside "
> + "conditionals\n");
> + return COND_ERR;
> +}
> +
> +int define_filename_trans(void)
> +{
> + char *id, *name = NULL;
> + type_set_t stypes, ttypes;
> + ebitmap_t e_stypes, e_ttypes;
> + ebitmap_t e_tclasses;
> + ebitmap_node_t *snode, *tnode, *cnode;
> + filename_trans_t *ft;
> + filename_trans_rule_t *ftr;
> + class_datum_t *cladatum;
> + type_datum_t *typdatum;
> + uint32_t otype;
> + unsigned int c, s, t;
> + int add;
> +
> + if (pass == 1) {
> + /* stype */
> + while ((id = queue_remove(id_queue)))
> + free(id);
> + /* ttype */
> + while ((id = queue_remove(id_queue)))
> + free(id);
> + /* tclass */
> + while ((id = queue_remove(id_queue)))
> + free(id);
> + /* otype */
> + id = queue_remove(id_queue);
> + free(id);
> + /* name */
> + id = queue_remove(id_queue);
> + free(id);
> + return 0;
> + }
> +
> +
> + add = 1;
> + type_set_init(&stypes);
> + while ((id = queue_remove(id_queue))) {
> + if (set_types(&stypes, id, &add, 0))
> + goto bad;
> + }
> +
> + add =1;
> + type_set_init(&ttypes);
> + while ((id = queue_remove(id_queue))) {
> + if (set_types(&ttypes, id, &add, 0))
> + goto bad;
> + }
> +
> + ebitmap_init(&e_tclasses);
> + while ((id = queue_remove(id_queue))) {
> + if (!is_id_in_scope(SYM_CLASSES, id)) {
> + yyerror2("class %s is not within scope", id);
> + free(id);
> + goto bad;
> + }
> + cladatum = hashtab_search(policydbp->p_classes.table, id);
> + if (!cladatum) {
> + yyerror2("unknown class %s", id);
> + goto bad;
> + }
> + if (ebitmap_set_bit(&e_tclasses, cladatum->s.value - 1,
> TRUE)) {
> + yyerror("Out of memory");
> + goto bad;
> + }
> + free(id);
> + }
> +
> + id = (char *)queue_remove(id_queue);
> + if (!id) {
> + yyerror("no otype in transition definition?");
> + goto bad;
> + }
> + if (!is_id_in_scope(SYM_TYPES, id)) {
> + yyerror2("type %s is not within scope", id);
> + free(id);
> + goto bad;
> + }
> + typdatum = hashtab_search(policydbp->p_types.table, id);
> + if (!typdatum) {
> + yyerror2("unknown type %s used in transition definition",
> id);
> + goto bad;
> + }
> + free(id);
> + otype = typdatum->s.value;
> +
> + name = queue_remove(id_queue);
> + if (!name) {
> + yyerror("no pathname specified in filename_trans
> definition?");
> + goto bad;
> + }
> +
> + /* We expand the class set into seperate rules. We expand the types
> + * just to make sure there are not duplicates. They will get turned
> + * into seperate rules later */
> + ebitmap_init(&e_stypes);
> + if (type_set_expand(&stypes, &e_stypes, policydbp, 1))
> + goto bad;
> +
> + ebitmap_init(&e_ttypes);
> + if (type_set_expand(&ttypes, &e_ttypes, policydbp, 1))
> + goto bad;
> +
> + ebitmap_for_each_bit(&e_tclasses, cnode, c) {
> + if (!ebitmap_node_get_bit(cnode, c))
> + continue;
> + ebitmap_for_each_bit(&e_stypes, snode, s) {
> + if (!ebitmap_node_get_bit(snode, s))
> + continue;
> + ebitmap_for_each_bit(&e_ttypes, tnode, t) {
> + if (!ebitmap_node_get_bit(tnode, t))
> + continue;
> +
> + for (ft = policydbp->filename_trans; ft;
> ft = ft->next) {
> + if (ft->stype == (s + 1) &&
> + ft->ttype == (t + 1) &&
> + ft->tclass == (c + 1) &&
> + !strcmp(ft->name, name)) {
> + yyerror2("duplicate
> filename transition for: filename_trans %s %s %s:%s",
> + name,
> +
> policydbp->p_type_val_to_name[s],
> +
> policydbp->p_type_val_to_name[t],
> +
> policydbp->p_class_val_to_name[c]);
> + goto bad;
> + }
> + }
> +
> + ft = malloc(sizeof(*ft));
> + if (!ft) {
> + yyerror("out of memory");
> + goto bad;
> + }
> + memset(ft, 0, sizeof(*ft));
> +
> + ft->next = policydbp->filename_trans;
> + policydbp->filename_trans = ft;
> +
> + ft->name = strdup(name);
> + if (!ft->name) {
> + yyerror("out of memory");
> + goto bad;
> + }
> + ft->stype = s + 1;
> + ft->ttype = t + 1;
> + ft->tclass = c + 1;
> + ft->otype = otype;
> + }
> + }
> +
> + /* Now add the real rule since we didn't find any duplicates
> */
> + ftr = malloc(sizeof(*ftr));
> + if (!ftr) {
> + yyerror("out of memory");
> + goto bad;
> + }
> + filename_trans_rule_init(ftr);
> + append_filename_trans(ftr);
> +
> + ftr->name = strdup(name);
> + ftr->stypes = stypes;
> + ftr->ttypes = ttypes;
> + ftr->tclass = c + 1;
> + ftr->otype = otype;
> + }
> +
> + free(name);
> + ebitmap_destroy(&e_stypes);
> + ebitmap_destroy(&e_ttypes);
> + ebitmap_destroy(&e_tclasses);
> +
> + return 0;
> +
> +bad:
> + free(name);
> + return -1;
> +}
> +
> static constraint_expr_t *constraint_expr_clone(constraint_expr_t * expr)
> {
> constraint_expr_t *h = NULL, *l = NULL, *e, *newe;
> diff -up checkpolicy-2.0.23/policy_define.h.eparis2
> checkpolicy-2.0.23/policy_define.h
> --- checkpolicy-2.0.23/policy_define.h.eparis2 2010-12-21
> 16:35:45.000000000 -0500
> +++ checkpolicy-2.0.23/policy_define.h 2011-03-28 13:50:05.489297128
> -0400
> @@ -16,6 +16,7 @@
> avrule_t *define_cond_compute_type(int which);
> avrule_t *define_cond_pol_list(avrule_t *avlist, avrule_t *stmt);
> avrule_t *define_cond_te_avtab(int which);
> +avrule_t *define_cond_filename_trans(void);
> cond_expr_t *define_cond_expr(uint32_t expr_type, void *arg1, void* arg2);
> int define_attrib(void);
> int define_av_perms(int inherits);
> @@ -47,6 +48,7 @@ int define_range_trans(int class_specifi
> int define_role_allow(void);
> int define_role_trans(void);
> int define_role_types(void);
> +int define_filename_trans(void);
> int define_sens(void);
> int define_te_avtab(int which);
> int define_typealias(void);
> diff -up checkpolicy-2.0.23/policy_parse.y.eparis2
> checkpolicy-2.0.23/policy_parse.y
> --- checkpolicy-2.0.23/policy_parse.y.eparis2 2011-03-23
> 14:19:51.133528148 -0400
> +++ checkpolicy-2.0.23/policy_parse.y 2011-03-28 13:49:03.489482156
> -0400
> @@ -342,7 +342,10 @@ cond_rule_def : cond_transitio
> | require_block
> { $$ = NULL; }
> ;
> -cond_transition_def : TYPE_TRANSITION names names ':' names identifier
> ';'
> +cond_transition_def : TYPE_TRANSITION names names ':' names identifier
> identifier ';'
> + { $$ = define_cond_filename_trans() ;
> + if ($$ == COND_ERR) return -1;}
> + | TYPE_TRANSITION names names ':' names identifier
> ';'
> { $$ =
> define_cond_compute_type(AVRULE_TRANSITION) ;
> if ($$ == COND_ERR) return -1;}
> | TYPE_MEMBER names names ':' names identifier ';'
> @@ -377,7 +380,10 @@ cond_dontaudit_def : DONTAUDIT names nam
> { $$ = define_cond_te_avtab(AVRULE_DONTAUDIT);
> if ($$ == COND_ERR) return -1; }
> ;
> -transition_def : TYPE_TRANSITION names names ':' names identifier
> ';'
> + ;
> +transition_def : TYPE_TRANSITION names names ':' names identifier
> identifier ';'
> + {if (define_filename_trans()) return -1; }
> + | TYPE_TRANSITION names names ':' names identifier
> ';'
> {if (define_compute_type(AVRULE_TRANSITION))
> return -1;}
> | TYPE_MEMBER names names ':' names identifier ';'
> {if (define_compute_type(AVRULE_MEMBER)) return
> -1;}
> diff -up checkpolicy-2.0.23/test/dismod.c.eparis2
> checkpolicy-2.0.23/test/dismod.c
> --- checkpolicy-2.0.23/test/dismod.c.eparis2 2011-03-23
> 14:19:51.142529423 -0400
> +++ checkpolicy-2.0.23/test/dismod.c 2011-03-23 14:19:51.160531973
> -0400
> @@ -52,6 +52,7 @@
> #define DISPLAY_AVBLOCK_ROLE_ALLOW 4
> #define DISPLAY_AVBLOCK_REQUIRES 5
> #define DISPLAY_AVBLOCK_DECLARES 6
> +#define DISPLAY_AVBLOCK_FILENAME_TRANS 7
>
> static policydb_t policydb;
> extern unsigned int ss_initialized;
> @@ -480,6 +481,18 @@ void display_role_allow(role_allow_rule_
> }
> }
>
> +void display_filename_trans(filename_trans_rule_t * tr, policydb_t * p, FILE
> * fp)
> +{
> + for (; tr; tr = tr->next) {
> + fprintf(fp, "filename transition %s", tr->name);
> + display_type_set(&tr->stypes, 0, p, fp);
> + display_type_set(&tr->ttypes, 0, p, fp);
> + display_id(p, fp, SYM_CLASSES, tr->tclass - 1, ":");
> + display_id(p, fp, SYM_TYPES, tr->otype - 1, "");
> + fprintf(fp, "\n");
> + }
> +}
> +
> int role_display_callback(hashtab_key_t key, hashtab_datum_t datum, void
> *data)
> {
> role_datum_t *role;
> @@ -647,6 +660,11 @@ int display_avdecl(avrule_decl_t * decl,
> }
> break;
> }
> + case DISPLAY_AVBLOCK_FILENAME_TRANS:
> + display_filename_trans(decl->filename_trans_rules,
> policy,
> + out_fp);
> + return -1;
> + break;
> default:{
> assert(0);
> }
> @@ -812,6 +830,7 @@ int menu()
> printf("c) Display policy capabilities\n");
> printf("l) Link in a module\n");
> printf("u) Display the unknown handling setting\n");
> + printf("F) Display filename_trans rules\n");
> printf("\n");
> printf("f) set output file\n");
> printf("m) display menu\n");
> @@ -947,6 +966,11 @@ int main(int argc, char **argv)
> if (out_fp != stdout)
> printf("\nOutput to file: %s\n",
> OutfileName);
> break;
> + case 'F':
> + fprintf(out_fp, "filename_trans rules:\n");
> + display_avblock(DISPLAY_AVBLOCK_FILENAME_TRANS,
> + 0, &policydb, out_fp);
> + break;
> case 'l':
> link_module(&policydb, out_fp);
> break;
> diff -up checkpolicy-2.0.23/test/dispol.c.eparis2
> checkpolicy-2.0.23/test/dispol.c
> --- checkpolicy-2.0.23/test/dispol.c.eparis2 2010-12-21
> 16:35:45.000000000 -0500
> +++ checkpolicy-2.0.23/test/dispol.c 2011-03-23 14:19:51.162532256
> -0400
> @@ -341,6 +341,21 @@ static void display_permissive(policydb_
> }
> }
>
> +static void display_filename_trans(policydb_t *p, FILE *fp)
> +{
> + filename_trans_t *ft;
> +
> + fprintf(fp, "filename_trans rules:\n");
> + for (ft = p->filename_trans; ft; ft = ft->next) {
> + fprintf(fp, "%s\n", ft->name);
> + display_id(p, fp, SYM_TYPES, ft->stype - 1, "");
> + display_id(p, fp, SYM_TYPES, ft->ttype - 1, "");
> + display_id(p, fp, SYM_CLASSES, ft->tclass - 1, ":");
> + display_id(p, fp, SYM_TYPES, ft->otype - 1, "");
> + fprintf(fp, "\n");
> + }
> +}
> +
> int menu()
> {
> printf("\nSelect a command:\n");
> @@ -355,6 +370,8 @@ int menu()
> printf("c) display policy capabilities\n");
> printf("p) display the list of permissive types\n");
> printf("u) display unknown handling setting\n");
> + printf("F) display filename_trans rules\n");
> + printf("\n");
> printf("f) set output file\n");
> printf("m) display menu\n");
> printf("q) quit\n");
> @@ -492,6 +509,9 @@ int main(int argc, char **argv)
> if (out_fp != stdout)
> printf("\nOutput to file: %s\n",
> OutfileName);
> break;
> + case 'F':
> + display_filename_trans(&policydb, out_fp);
> + break;
> case 'q':
> policydb_destroy(&policydb);
> exit(0);
>
>
>
> --
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