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Add sepol_compute_av_reason_buffer patch from Richard Haines

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This commit is contained in:
Dan Walsh 2012-11-19 09:10:41 -05:00
parent eb4908df1b
commit 0557b38137
2 changed files with 843 additions and 1 deletions
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839
libsepol-rhat.patch
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@ -11,6 +11,47 @@ index f90a48d..9152446 100644
POLICYDB_CAPABILITY_ALWAYSNETWORK,
__POLICYDB_CAPABILITY_MAX
};
diff --git a/libsepol/include/sepol/policydb/services.h b/libsepol/include/sepol/policydb/services.h
index aef0c7b..3fd9700 100644
--- a/libsepol/include/sepol/policydb/services.h
+++ b/libsepol/include/sepol/policydb/services.h
@@ -58,6 +58,36 @@ extern int sepol_compute_av_reason(sepol_security_id_t ssid,
struct sepol_av_decision *avd,
unsigned int *reason);
+/*
+ * Same as above, but also returns the constraint expression calculations
+ * whether allowed or denied in a buffer. This buffer is allocated by
+ * this call and must be free'd by the caller.
+ * The contraint buffer is in RPN format.
+ */
+extern int sepol_compute_av_reason_buffer(sepol_security_id_t ssid,
+ sepol_security_id_t tsid,
+ sepol_security_class_t tclass,
+ sepol_access_vector_t requested,
+ struct sepol_av_decision *avd,
+ unsigned int *reason,
+ char **reason_buf);
+
+/*
+ * Return a class ID associated with the class string representation
+ * specified by `class_name'.
+ */
+extern int sepol_class_name_to_id(const char *class_name,
+ sepol_security_class_t *tclass);
+
+/*
+ * Return a permission av bit associated with tclass and the string
+ * representation of the `perm_name'.
+ */
+extern int sepol_perm_name_to_av(sepol_security_class_t tclass,
+ const char *perm_name,
+ sepol_access_vector_t *av);
+
+
/*
* Compute a SID to use for labeling a new object in the
* class `tclass' based on a SID pair.
diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
index 2003eb6..a2d209c 100644
--- a/libsepol/src/expand.c
@ -265,3 +306,801 @@ index 43a71a7..7615a9b 100644
"always_check_network", /* POLICYDB_CAPABILITY_ALWAYSNETWORK */
NULL
};
diff --git a/libsepol/src/services.c b/libsepol/src/services.c
index 9c2920c..04f9978 100644
--- a/libsepol/src/services.c
+++ b/libsepol/src/services.c
@@ -54,6 +54,7 @@
#include <sepol/policydb/services.h>
#include <sepol/policydb/conditional.h>
#include <sepol/policydb/flask.h>
+#include <sepol/policydb/util.h>
#include "debug.h"
#include "private.h"
@@ -112,20 +113,208 @@ int sepol_set_policydb_from_file(FILE * fp)
static uint32_t latest_granting = 0;
/*
- * Return the boolean value of a constraint expression
- * when it is applied to the specified source and target
+ * Start of changes to support constraint reason failures.
+ */
+
+/*
+ * get_names_list obtains the list of users, roles or types when expr
+ * has a names list. For 'types' only, find how many in the name list, and
+ * then the attributes associated to them (also count these). When
+ * complete take the list of attributes and find those whose count
+ * matches the number of types. The attributes in the final list will be
+ * one of those that needs to has the type added (but which one !!!).
+ *
+ * The best way to solve this is for the compilers (checkpolicy and
+ * checkmodule) to add attributes to the constraint_expr_t structure
+ * (see constraint.h). The CIL compiler does add attribute names to
+ * constraint_expr_t->names, but the kernel does not translate them to
+ * types (i.e. the 30-04-12 version of the CIL compiler does not build
+ * the policy correctly).
+ *
+ * Note that the type_datum_t ->types (policydb.h) does not contain
+ * a list of types when inspecting a binary policy. This is only used
+ * in the *.pp modules.
+ */
+int get_names_list(const ebitmap_t * e, int type, char ** expr_buf)
+{
+ type_datum_t *t1 = NULL;
+
+#define MAX_ATTRS 300
+ /* Hold the type attribute names and count of instances */
+ struct attr_entries {
+ unsigned int entry;
+ int count;
+ } attr_info[MAX_ATTRS];
+
+ int struct_count = 0;
+ int x;
+
+ int rc = 0;
+ unsigned int i;
+ int entry_count = 0;
+ int is_attr = 0;
+
+ char tmp_buf[100];
+ /* if empty_set is 0, then <empty_set> */
+ int empty_set = 0;
+
+ ebitmap_t *attr;
+ unsigned int j;
+
+ int type_count = 0;
+
+ if (!*expr_buf)
+ return 0;
+
+ for (x = 0; x < MAX_ATTRS; x++) {
+ attr_info[x].entry = '\0';
+ attr_info[x].count = '\0';
+ }
+
+ /* For type entries find how many entries so we can check attributes */
+ if (type == CEXPR_TYPE) {
+ for (j = ebitmap_startbit(e); j < ebitmap_length(e); j++) {
+ if ((rc = ebitmap_get_bit(e, j)) == 0)
+ continue;
+ type_count++;
+ }
+ }
+
+ /* Start the list of names where e = &e->names */
+ strcat(*expr_buf, "{ ");
+
+ for (i = ebitmap_startbit(e); i < ebitmap_length(e); i++) {
+ if ((rc = ebitmap_get_bit(e, i)) == 0)
+ continue;
+
+ switch (type) {
+ case CEXPR_USER:
+ sprintf(tmp_buf, "%s ", policydb->p_user_val_to_name[i]);
+ strcat(*expr_buf, tmp_buf);
+ break;
+
+ case CEXPR_ROLE:
+ sprintf(tmp_buf, "%s ", policydb->p_role_val_to_name[i]);
+ strcat(*expr_buf, tmp_buf);
+ break;
+
+ case CEXPR_TYPE:
+/*
+ * When checking a type for associated attributes, you can get a number
+ * of attributes, any one of which could be the one to update, for example:
+ *
+ * constrain process { transition noatsecure siginh rlimitinh }
+ * (
+ * r1 == r2
+ * or ( t1 == can_change_process_role and t2 == process_user_target )
+ * or ( t1 == cron_source_domain and t2 == cron_job_domain )
+ * or ( t1 == can_system_change and r2 == system_r )
+ * or ( t1 == process_uncond_exempt )
+ * );
+ *
+ * for the 'targeted' policy it will yeld for "can_change_process_role"
+ * the following possible entries: can_change_process_role,
+ * nsswitch_domain or domain as each type that makes up
+ * "can_change_process_role" is also in the others.
+ *
+ * The "cron_source_domain" will give the largest amount of attributes
+ * as there is only one type (crond_t) but has 36 associations.
+ */
+ /*
+ * Get node for the type ID and if an attribute just add name,
+ * otherwise find the list of attrs associated to this type.
+ */
+ t1 = policydb->type_val_to_struct[i];
+ if (t1->flavor == TYPE_ATTRIB) {
+ is_attr = 1;
+ sprintf(tmp_buf, "%s ", policydb->p_type_val_to_name[i]);
+ strcat(*expr_buf, tmp_buf);
+ break;
+ } else {
+ /* Have type so but names in buffer and sort out attrs */
+ sprintf(tmp_buf, "%s ", policydb->p_type_val_to_name[i]);
+ strcat(*expr_buf, tmp_buf);
+ /* Process attributes attached to the type */
+ attr = &policydb->type_attr_map[t1->s.value-1];
+ unsigned int z;
+ struct_count = 0;
+ for (z = ebitmap_startbit(attr); z < ebitmap_length(attr); z++) {
+ if ((rc = ebitmap_get_bit(attr, z)) == 0)
+ continue;
+ t1 = policydb->type_val_to_struct[z];
+ if (t1->flavor == TYPE_ATTRIB) {
+ x = 0;
+ while (x < MAX_ATTRS) {
+ if (attr_info[x].entry == z) {
+ attr_info[x].entry = z;
+ attr_info[x].count++;
+ break;
+ }
+ if (attr_info[x].entry == 0) {
+ attr_info[x].entry = z;
+ attr_info[x].count++;
+ break;
+ }
+ x++;
+ }
+ struct_count++;
+ }
+ }
+ break;
+ }
+ break;
+
+ default:
+ ERR(NULL, "Invalid u_r_t value: %d\n", type);
+ return -1;
+ break;
+ }
+ empty_set++;
+ entry_count++;
+ }
+
+ /* End the list of names but if type then check for attributes. */
+ if (empty_set == 0) {
+ strcat(*expr_buf, "<empty_set> }");
+ } else if (type == CEXPR_TYPE && is_attr == 0) {
+ strcat(*expr_buf, "} ** Attributes associated to the types: ");
+ for (x = 0; x < MAX_ATTRS; x++) {
+ if (attr_info[x].count == type_count) {
+ sprintf(tmp_buf, "%s ", policydb->p_type_val_to_name[attr_info[x].entry]);
+ strcat(*expr_buf, tmp_buf);
+ }
+ }
+ strcat(*expr_buf, "**");
+ } else
+ strcat(*expr_buf, "}");
+ return 0;
+}
+
+
+/*
+ * Modified version of constraint_expr_eval
+ *
+ * Return the boolean value of a constraint expression
+ * when it is applied to the specified source and target
* security contexts.
*
* xcontext is a special beast... It is used by the validatetrans rules
* only. For these rules, scontext is the context before the transition,
* tcontext is the context after the transition, and xcontext is the context
* of the process performing the transition. All other callers of
- * constraint_expr_eval should pass in NULL for xcontext.
+ * constraint_expr_eval_reason should pass in NULL for xcontext.
+ *
+ * This function will also build a buffer as the constraint is processed
+ * for analysis. If this option is not required, then:
+ * 'tclass' and 'allowed' should be '0' and expr_buf MUST be NULL.
*/
-static int constraint_expr_eval(context_struct_t * scontext,
+static int constraint_expr_eval_reason(context_struct_t * scontext,
context_struct_t * tcontext,
context_struct_t * xcontext,
- constraint_expr_t * cexpr)
+ sepol_security_class_t tclass,
+ sepol_access_vector_t allowed,
+ constraint_expr_t * cexpr,
+ char ** expr_buf)
{
uint32_t val1, val2;
context_struct_t *c;
@@ -135,21 +324,68 @@ static int constraint_expr_eval(context_struct_t * scontext,
int s[CEXPR_MAXDEPTH];
int sp = -1;
+ char tmp_buf[1024];
+
+/*
+ * Define the s_t_x_num values that make up r1, t2 etc. in text strings
+ * Set 1 = source, 2 = target, 3 = xcontext for validatetrans
+ */
+#define SOURCE 1
+#define TARGET 2
+#define XTARGET 3
+
+ int s_t_x_num = SOURCE;
+
+ /* Set 0 = fail, u = CEXPR_USER, r = CEXPR_ROLE, t = CEXPR_TYPE */
+ int u_r_t = 0;
+
+ char *name1, *name2;
+
+ if (*expr_buf) {
+ /* Get constraint statement type */
+ sprintf(tmp_buf, "constrain ");
+ for (e = cexpr; e; e = e->next) {
+ if (e->attr >= CEXPR_L1L2) {
+ sprintf(tmp_buf, "mlsconstrain ");
+ break;
+ }
+ }
+ strcat(*expr_buf, tmp_buf);
+
+ /* Get class entry */
+ sprintf(tmp_buf, "%s ", policydb->p_class_val_to_name[tclass - 1]);
+ strcat(*expr_buf, tmp_buf);
+
+ /*
+ * Get permission entries sepol_av_to_string defined in util.c
+ * and its buffer to hold the perm list is 1024 chars.
+ */
+ sprintf(tmp_buf, "{%s } ", sepol_av_to_string(policydb, tclass, allowed));
+ strcat(*expr_buf, tmp_buf);
+ }
+
+ /* Original function but with buffer support */
for (e = cexpr; e; e = e->next) {
switch (e->expr_type) {
case CEXPR_NOT:
BUG_ON(sp < 0);
s[sp] = !s[sp];
+ if (*expr_buf)
+ strcat(*expr_buf, " not ");
break;
case CEXPR_AND:
BUG_ON(sp < 1);
sp--;
s[sp] &= s[sp + 1];
+ if (*expr_buf)
+ strcat(*expr_buf, " and ");
break;
case CEXPR_OR:
BUG_ON(sp < 1);
sp--;
s[sp] |= s[sp + 1];
+ if (*expr_buf)
+ strcat(*expr_buf, " or ");
break;
case CEXPR_ATTR:
if (sp == (CEXPR_MAXDEPTH - 1))
@@ -158,33 +394,57 @@ static int constraint_expr_eval(context_struct_t * scontext,
case CEXPR_USER:
val1 = scontext->user;
val2 = tcontext->user;
+ if (*expr_buf)
+ strcat(*expr_buf, "(u1 u2 ");
break;
case CEXPR_TYPE:
val1 = scontext->type;
val2 = tcontext->type;
+ if (*expr_buf)
+ strcat(*expr_buf, "(t1 t2 ");
break;
case CEXPR_ROLE:
val1 = scontext->role;
val2 = tcontext->role;
r1 = policydb->role_val_to_struct[val1 - 1];
r2 = policydb->role_val_to_struct[val2 - 1];
+ if (*expr_buf) {
+ name1 = policydb->p_role_val_to_name[r1->s.value - 1];
+ name2 = policydb->p_role_val_to_name[r2->s.value - 1];
+ sprintf(tmp_buf, "(r1-%s r2-%s ", name1, name2);
+ strcat(*expr_buf, tmp_buf);
+ }
switch (e->op) {
case CEXPR_DOM:
- s[++sp] =
- ebitmap_get_bit(&r1->dominates,
- val2 - 1);
+ s[++sp] = ebitmap_get_bit(&r1->dominates, val2 - 1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "dom -Fail-) ");
+ } else {
+ strcat(*expr_buf, "dom -Fail-) ");
+ }
+ }
continue;
case CEXPR_DOMBY:
- s[++sp] =
- ebitmap_get_bit(&r2->dominates,
- val1 - 1);
+ s[++sp] = ebitmap_get_bit(&r2->dominates, val1 - 1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "domby -Fail-) ");
+ } else {
+ strcat(*expr_buf, "domby +Pass+) ");
+ }
+ }
continue;
case CEXPR_INCOMP:
- s[++sp] =
- (!ebitmap_get_bit
- (&r1->dominates, val2 - 1)
- && !ebitmap_get_bit(&r2->dominates,
- val1 - 1));
+ s[++sp] = (!ebitmap_get_bit(&r1->dominates, val2 - 1)
+ && !ebitmap_get_bit(&r2->dominates, val1 - 1));
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "incomp -Fail-) ");
+ } else {
+ strcat(*expr_buf, "incomp +Pass+) ");
+ }
+ }
continue;
default:
break;
@@ -193,43 +453,90 @@ static int constraint_expr_eval(context_struct_t * scontext,
case CEXPR_L1L2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[0]);
+ if (*expr_buf)
+ strcat(*expr_buf, "(l1 l2 ");
goto mls_ops;
case CEXPR_L1H2:
l1 = &(scontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
+ if (*expr_buf)
+ strcat(*expr_buf, "(l1 h2 ");
goto mls_ops;
case CEXPR_H1L2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[0]);
+ if (*expr_buf)
+ strcat(*expr_buf,"(h1 l2 ");
goto mls_ops;
case CEXPR_H1H2:
l1 = &(scontext->range.level[1]);
l2 = &(tcontext->range.level[1]);
+ if (*expr_buf)
+ strcat(*expr_buf, "(h1 h2 ");
goto mls_ops;
case CEXPR_L1H1:
l1 = &(scontext->range.level[0]);
l2 = &(scontext->range.level[1]);
+ if (*expr_buf)
+ strcat(*expr_buf, "(l1 h1 ");
goto mls_ops;
case CEXPR_L2H2:
l1 = &(tcontext->range.level[0]);
l2 = &(tcontext->range.level[1]);
+ if (*expr_buf)
+ strcat(*expr_buf, "(l2 h2 ");
goto mls_ops;
- mls_ops:
+ mls_ops:
switch (e->op) {
case CEXPR_EQ:
s[++sp] = mls_level_eq(l1, l2);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "eq -Fail-) ");
+ } else {
+ strcat(*expr_buf, "eq +Pass+) ");
+ }
+ }
continue;
case CEXPR_NEQ:
s[++sp] = !mls_level_eq(l1, l2);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "neq -Fail-) ");
+ } else {
+ strcat(*expr_buf, "neq +Pass+) ");
+ }
+ }
continue;
case CEXPR_DOM:
s[++sp] = mls_level_dom(l1, l2);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "dom -Fail-) ");
+ } else {
+ strcat(*expr_buf, "dom +Pass+) ");
+ }
+ }
continue;
case CEXPR_DOMBY:
s[++sp] = mls_level_dom(l2, l1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "domby -Fail-) ");
+ } else {
+ strcat(*expr_buf, "domby +Pass+) ");
+ }
+ }
continue;
case CEXPR_INCOMP:
s[++sp] = mls_level_incomp(l2, l1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "incomp -Fail-) ");
+ } else {
+ strcat(*expr_buf, "incomp +Pass+) ");
+ }
+ }
continue;
default:
BUG();
@@ -244,9 +551,23 @@ static int constraint_expr_eval(context_struct_t * scontext,
switch (e->op) {
case CEXPR_EQ:
s[++sp] = (val1 == val2);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "eq -Fail-) ");
+ } else {
+ strcat(*expr_buf, "eq +Pass+) ");
+ }
+ }
break;
case CEXPR_NEQ:
s[++sp] = (val1 != val2);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, "neq -Fail-) ");
+ } else {
+ strcat(*expr_buf, "neq +Pass+) ");
+ }
+ }
break;
default:
BUG();
@@ -256,22 +577,46 @@ static int constraint_expr_eval(context_struct_t * scontext,
case CEXPR_NAMES:
if (sp == (CEXPR_MAXDEPTH - 1))
return 0;
+ s_t_x_num = SOURCE;
c = scontext;
- if (e->attr & CEXPR_TARGET)
+ if (e->attr & CEXPR_TARGET) {
+ s_t_x_num = TARGET;
c = tcontext;
- else if (e->attr & CEXPR_XTARGET) {
+ } else if (e->attr & CEXPR_XTARGET) {
+ s_t_x_num = XTARGET;
c = xcontext;
- if (!c) {
- BUG();
- return 0;
- }
}
- if (e->attr & CEXPR_USER)
+ if (!c) {
+ BUG();
+ return 0;
+ }
+ if (e->attr & CEXPR_USER) {
+ u_r_t = CEXPR_USER;
val1 = c->user;
- else if (e->attr & CEXPR_ROLE)
+ if (*expr_buf) {
+ name1 = policydb->p_user_val_to_name[val1 - 1];
+ sprintf(tmp_buf, "(u%d-%s ", s_t_x_num, name1);
+ strcat(*expr_buf, tmp_buf);
+ }
+ }
+ else if (e->attr & CEXPR_ROLE) {
+ u_r_t = CEXPR_ROLE;
val1 = c->role;
- else if (e->attr & CEXPR_TYPE)
+ if (*expr_buf) {
+ name1 = policydb->p_role_val_to_name[val1 - 1];
+ sprintf(tmp_buf, "(r%d-%s ", s_t_x_num, name1);
+ strcat(*expr_buf, tmp_buf);
+ }
+ }
+ else if (e->attr & CEXPR_TYPE) {
+ u_r_t = CEXPR_TYPE;
val1 = c->type;
+ if (*expr_buf) {
+ name1 = policydb->p_type_val_to_name[val1 - 1];
+ sprintf(tmp_buf, "(t%d-%s ", s_t_x_num, name1);
+ strcat(*expr_buf, tmp_buf);
+ }
+ }
else {
BUG();
return 0;
@@ -279,10 +624,61 @@ static int constraint_expr_eval(context_struct_t * scontext,
switch (e->op) {
case CEXPR_EQ:
+ switch (u_r_t) {
+ case CEXPR_USER:
+ name1 = policydb->p_user_val_to_name[val1 - 1];
+ break;
+ case CEXPR_ROLE:
+ name1 = policydb->p_role_val_to_name[val1 - 1];
+ break;
+ case CEXPR_TYPE:
+ name1 = policydb->p_type_val_to_name[val1 - 1];
+ break;
+ default:
+ name1 = NULL;
+ ERR(NULL, "unrecognized u_r_t Value: %d", u_r_t);
+ break;
+ }
+
+ get_names_list(&e->names, u_r_t, expr_buf);
+
s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, " eq -Fail-) ");
+ } else {
+ strcat(*expr_buf, " eq +Pass+) ");
+ }
+ }
break;
+
case CEXPR_NEQ:
+ switch (u_r_t) {
+ case CEXPR_USER:
+ name1 = policydb->p_user_val_to_name[val1 - 1];
+ break;
+ case CEXPR_ROLE:
+ name1 = policydb->p_role_val_to_name[val1 - 1];
+ break;
+ case CEXPR_TYPE:
+ name1 = policydb->p_type_val_to_name[val1 - 1];
+ break;
+ default:
+ name1 = NULL;
+ ERR(NULL, "unrecognized u_r_t Value: %d", u_r_t);
+ break;
+ }
+
+ get_names_list(&e->names, u_r_t, expr_buf);
+
s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
+ if (*expr_buf) {
+ if (s[sp] == 0) {
+ strcat(*expr_buf, " neq -Fail-) ");
+ } else {
+ strcat(*expr_buf, " neq +Pass+) ");
+ }
+ }
break;
default:
BUG();
@@ -296,9 +692,21 @@ static int constraint_expr_eval(context_struct_t * scontext,
}
BUG_ON(sp != 0);
+
+ if (*expr_buf) {
+ if (s[0] == 0) {
+ char *denied = {"\n** Constraint DENIED access **\n\n"};
+ strcat(*expr_buf, denied);
+ } else {
+ char *allow = {"\n** Constraint ALLOWED access **\n\n"};
+ strcat(*expr_buf, allow);
+ }
+ }
return s[0];
}
+
+
/*
* Compute access vectors based on a context structure pair for
* the permissions in a particular class.
@@ -308,7 +716,8 @@ static int context_struct_compute_av(context_struct_t * scontext,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
- unsigned int *reason)
+ unsigned int *reason,
+ char *expr_buf)
{
constraint_node_t *constraint;
struct role_allow *ra;
@@ -383,8 +792,8 @@ static int context_struct_compute_av(context_struct_t * scontext,
constraint = tclass_datum->constraints;
while (constraint) {
if ((constraint->permissions & (avd->allowed)) &&
- !constraint_expr_eval(scontext, tcontext, NULL,
- constraint->expr)) {
+ !constraint_expr_eval_reason(scontext, tcontext, NULL,
+ tclass, avd->allowed, constraint->expr, &expr_buf)) {
avd->allowed =
(avd->allowed) & ~(constraint->permissions);
}
@@ -459,8 +868,8 @@ int hidden sepol_validate_transition(sepol_security_id_t oldsid,
constraint = tclass_datum->validatetrans;
while (constraint) {
- if (!constraint_expr_eval(ocontext, ncontext, tcontext,
- constraint->expr)) {
+ if (!constraint_expr_eval_reason(ocontext, ncontext, tcontext,
+ 0, 0, constraint->expr, NULL)) {
return -EPERM;
}
constraint = constraint->next;
@@ -469,13 +878,21 @@ int hidden sepol_validate_transition(sepol_security_id_t oldsid,
return 0;
}
-int hidden sepol_compute_av_reason(sepol_security_id_t ssid,
+/*
+ * sepol_compute_av_reason_buffer - the reason buffer is malloc'd
+ * to REASON_BUF_SIZE that seems okay for the Reference Policy.
+ * TODO manage size using realloc at some stage.
+ */
+#define REASON_BUF_SIZE 100000
+int hidden sepol_compute_av_reason_buffer(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
sepol_access_vector_t requested,
struct sepol_av_decision *avd,
- unsigned int *reason)
+ unsigned int *reason,
+ char **reason_buf)
{
+ char *expr_buf = NULL;
context_struct_t *scontext = 0, *tcontext = 0;
int rc = 0;
@@ -485,6 +902,7 @@ int hidden sepol_compute_av_reason(sepol_security_id_t ssid,
rc = -EINVAL;
goto out;
}
+
tcontext = sepol_sidtab_search(sidtab, tsid);
if (!tcontext) {
ERR(NULL, "unrecognized SID %d", tsid);
@@ -493,11 +911,36 @@ int hidden sepol_compute_av_reason(sepol_security_id_t ssid,
}
rc = context_struct_compute_av(scontext, tcontext, tclass,
- requested, avd, reason);
- out:
+ requested, avd, reason, expr_buf);
+ if (rc) {
+ goto out;
+ }
+
+ if (!avd->allowed && (*reason & SEPOL_COMPUTEAV_CONS) && reason_buf) {
+ expr_buf = calloc(REASON_BUF_SIZE,1);
+ if (!expr_buf) {
+ ERR(NULL, "malloc failed to allocate constraint reason buffer");
+ return -ENOMEM;
+ }
+ rc = context_struct_compute_av(scontext, tcontext, tclass,
+ requested, avd, reason, expr_buf);
+ *reason_buf = expr_buf;
+ }
+
+out:
return rc;
}
+int hidden sepol_compute_av_reason(sepol_security_id_t ssid,
+ sepol_security_id_t tsid,
+ sepol_security_class_t tclass,
+ sepol_access_vector_t requested,
+ struct sepol_av_decision *avd,
+ unsigned int *reason)
+{
+ return sepol_compute_av_reason_buffer(ssid, tsid, tclass, requested, avd, reason, NULL);
+}
+
int hidden sepol_compute_av(sepol_security_id_t ssid,
sepol_security_id_t tsid,
sepol_security_class_t tclass,
@@ -510,6 +953,65 @@ int hidden sepol_compute_av(sepol_security_id_t ssid,
}
/*
+ * Return a class ID associated with the class string representation
+ * specified by `class_name'.
+ */
+int hidden sepol_class_name_to_id(const char *class_name,
+ sepol_security_class_t *tclass)
+{
+ char *class = NULL;
+ sepol_security_class_t id;
+
+ for (id = 1; ; id++) {
+ if ((class = policydb->p_class_val_to_name[id - 1]) == NULL) {
+ ERR(NULL, "could not convert %s to class id", class_name);
+ return STATUS_ERR;
+ }
+ if ((strcmp(class, class_name)) == 0) {
+ *tclass = id;
+ return STATUS_SUCCESS;
+ }
+ }
+}
+
+/*
+ * Return access vertor bit associated with the class / permission string.
+ */
+int hidden sepol_perm_name_to_av(sepol_security_class_t tclass,
+ const char *perm_name,
+ sepol_access_vector_t *av)
+{
+ class_datum_t *tclass_datum;
+ perm_datum_t *base_perm;
+ perm_datum_t *common_perm;
+
+ if (!tclass || tclass > policydb->p_classes.nprim) {
+ ERR(NULL, "unrecognized class %d", tclass);
+ return -EINVAL;
+ }
+ tclass_datum = policydb->class_val_to_struct[tclass - 1];
+
+ base_perm = (perm_datum_t *)
+ hashtab_search(tclass_datum->permissions.table,
+ (hashtab_key_t)perm_name);
+ if (base_perm != NULL) {
+ *av = 0x1 << (base_perm->s.value - 1);
+ return STATUS_SUCCESS;
+ }
+
+ common_perm = (perm_datum_t *)
+ hashtab_search(tclass_datum->comdatum->permissions.table,
+ (hashtab_key_t)perm_name);
+ if (common_perm != NULL) {
+ *av = 0x1 << (common_perm->s.value - 1);
+ return STATUS_SUCCESS;
+ }
+
+ ERR(NULL, "could not convert %s to av bit", perm_name);
+ return STATUS_ERR;
+}
+
+/*
* Write the security context string representation of
* the context associated with `sid' into a dynamically
* allocated string of the correct size. Set `*scontext'
@@ -1337,7 +1839,7 @@ int hidden sepol_get_user_sids(sepol_security_id_t fromsid,
rc = context_struct_compute_av(fromcon, &usercon,
SECCLASS_PROCESS,
PROCESS__TRANSITION,
- &avd, &reason);
+ &avd, &reason, NULL);
if (rc || !(avd.allowed & PROCESS__TRANSITION))
continue;
rc = sepol_sidtab_context_to_sid(sidtab, &usercon,

5
libsepol.spec
View File

@ -1,7 +1,7 @@
Summary: SELinux binary policy manipulation library
Name: libsepol
Version: 2.1.8
Release: 2%{?dist}
Release: 3%{?dist}
License: LGPLv2+
Group: System Environment/Libraries
Source: http://www.nsa.gov/selinux/archives/libsepol-%{version}.tgz
@ -99,6 +99,9 @@ exit 0
/%{_lib}/libsepol.so.1
%changelog
* Mon Nov 19 2012 Dan Walsh <dwalsh@redhat.com> - 2.1.8-3
- Add sepol_compute_av_reason_buffer patch from Richard Haines
* Wed Sep 19 2012 Dan Walsh <dwalsh@redhat.com> - 2.1.8-2
- Revert patch that was attempting to expand filetrans attributes, but is breaking filetrans rules