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-rw-r--r--security/selinux/avc.c2
-rw-r--r--security/selinux/hooks.c15
-rw-r--r--security/selinux/include/avc.h4
-rw-r--r--security/selinux/include/security.h15
-rw-r--r--security/selinux/ss/policydb.c205
-rw-r--r--security/selinux/ss/policydb.h5
-rw-r--r--security/selinux/ss/services.c172
7 files changed, 398 insertions, 20 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 114b4b4c97b2..cb30c7e350b3 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -136,7 +136,7 @@ static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
* @tclass: target security class
* @av: access vector
*/
-static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
+void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
{
const char **common_pts = NULL;
u32 common_base = 0;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6b5790bba8f9..89f446d86054 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5226,8 +5226,12 @@ static int selinux_setprocattr(struct task_struct *p,
if (sid == 0)
return -EINVAL;
-
- /* Only allow single threaded processes to change context */
+ /*
+ * SELinux allows to change context in the following case only.
+ * - Single threaded processes.
+ * - Multi threaded processes intend to change its context into
+ * more restricted domain (defined by TYPEBOUNDS statement).
+ */
if (atomic_read(&p->mm->mm_users) != 1) {
struct task_struct *g, *t;
struct mm_struct *mm = p->mm;
@@ -5235,11 +5239,16 @@ static int selinux_setprocattr(struct task_struct *p,
do_each_thread(g, t) {
if (t->mm == mm && t != p) {
read_unlock(&tasklist_lock);
- return -EPERM;
+ error = security_bounded_transition(tsec->sid, sid);
+ if (!error)
+ goto boundary_ok;
+
+ return error;
}
} while_each_thread(g, t);
read_unlock(&tasklist_lock);
}
+boundary_ok:
/* Check permissions for the transition. */
error = avc_has_perm(tsec->sid, sid, SECCLASS_PROCESS,
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index 7b9769f5e775..d12ff1a9c0aa 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -12,6 +12,7 @@
#include <linux/kdev_t.h>
#include <linux/spinlock.h>
#include <linux/init.h>
+#include <linux/audit.h>
#include <linux/in6.h>
#include <linux/path.h>
#include <asm/system.h>
@@ -126,6 +127,9 @@ int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
u32 events, u32 ssid, u32 tsid,
u16 tclass, u32 perms);
+/* Shows permission in human readable form */
+void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av);
+
/* Exported to selinuxfs */
int avc_get_hash_stats(char *page);
extern unsigned int avc_cache_threshold;
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 7c543003d653..72447370bc95 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -27,13 +27,14 @@
#define POLICYDB_VERSION_RANGETRANS 21
#define POLICYDB_VERSION_POLCAP 22
#define POLICYDB_VERSION_PERMISSIVE 23
+#define POLICYDB_VERSION_BOUNDARY 24
/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
#ifdef CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX
#define POLICYDB_VERSION_MAX CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE
#else
-#define POLICYDB_VERSION_MAX POLICYDB_VERSION_PERMISSIVE
+#define POLICYDB_VERSION_MAX POLICYDB_VERSION_BOUNDARY
#endif
#define CONTEXT_MNT 0x01
@@ -62,6 +63,16 @@ enum {
extern int selinux_policycap_netpeer;
extern int selinux_policycap_openperm;
+/*
+ * type_datum properties
+ * available at the kernel policy version >= POLICYDB_VERSION_BOUNDARY
+ */
+#define TYPEDATUM_PROPERTY_PRIMARY 0x0001
+#define TYPEDATUM_PROPERTY_ATTRIBUTE 0x0002
+
+/* limitation of boundary depth */
+#define POLICYDB_BOUNDS_MAXDEPTH 4
+
int security_load_policy(void *data, size_t len);
int security_policycap_supported(unsigned int req_cap);
@@ -117,6 +128,8 @@ int security_node_sid(u16 domain, void *addr, u32 addrlen,
int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
u16 tclass);
+int security_bounded_transition(u32 oldsid, u32 newsid);
+
int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid);
int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 26646305dc0e..72e4a54973aa 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -30,6 +30,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
+#include <linux/audit.h>
#include "security.h"
#include "policydb.h"
@@ -116,7 +117,12 @@ static struct policydb_compat_info policydb_compat[] = {
.version = POLICYDB_VERSION_PERMISSIVE,
.sym_num = SYM_NUM,
.ocon_num = OCON_NUM,
- }
+ },
+ {
+ .version = POLICYDB_VERSION_BOUNDARY,
+ .sym_num = SYM_NUM,
+ .ocon_num = OCON_NUM,
+ },
};
static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -254,7 +260,9 @@ static int role_index(void *key, void *datum, void *datap)
role = datum;
p = datap;
- if (!role->value || role->value > p->p_roles.nprim)
+ if (!role->value
+ || role->value > p->p_roles.nprim
+ || role->bounds > p->p_roles.nprim)
return -EINVAL;
p->p_role_val_to_name[role->value - 1] = key;
p->role_val_to_struct[role->value - 1] = role;
@@ -270,9 +278,12 @@ static int type_index(void *key, void *datum, void *datap)
p = datap;
if (typdatum->primary) {
- if (!typdatum->value || typdatum->value > p->p_types.nprim)
+ if (!typdatum->value
+ || typdatum->value > p->p_types.nprim
+ || typdatum->bounds > p->p_types.nprim)
return -EINVAL;
p->p_type_val_to_name[typdatum->value - 1] = key;
+ p->type_val_to_struct[typdatum->value - 1] = typdatum;
}
return 0;
@@ -285,7 +296,9 @@ static int user_index(void *key, void *datum, void *datap)
usrdatum = datum;
p = datap;
- if (!usrdatum->value || usrdatum->value > p->p_users.nprim)
+ if (!usrdatum->value
+ || usrdatum->value > p->p_users.nprim
+ || usrdatum->bounds > p->p_users.nprim)
return -EINVAL;
p->p_user_val_to_name[usrdatum->value - 1] = key;
p->user_val_to_struct[usrdatum->value - 1] = usrdatum;
@@ -438,6 +451,14 @@ static int policydb_index_others(struct policydb *p)
goto out;
}
+ p->type_val_to_struct =
+ kmalloc(p->p_types.nprim * sizeof(*(p->type_val_to_struct)),
+ GFP_KERNEL);
+ if (!p->type_val_to_struct) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
if (cond_init_bool_indexes(p)) {
rc = -ENOMEM;
goto out;
@@ -625,6 +646,7 @@ void policydb_destroy(struct policydb *p)
kfree(p->class_val_to_struct);
kfree(p->role_val_to_struct);
kfree(p->user_val_to_struct);
+ kfree(p->type_val_to_struct);
avtab_destroy(&p->te_avtab);
@@ -1176,8 +1198,8 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
{
char *key = NULL;
struct role_datum *role;
- int rc;
- __le32 buf[2];
+ int rc, to_read = 2;
+ __le32 buf[3];
u32 len;
role = kzalloc(sizeof(*role), GFP_KERNEL);
@@ -1186,12 +1208,17 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
goto out;
}
- rc = next_entry(buf, fp, sizeof buf);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
+ to_read = 3;
+
+ rc = next_entry(buf, fp, sizeof(buf[0]) * to_read);
if (rc < 0)
goto bad;
len = le32_to_cpu(buf[0]);
role->value = le32_to_cpu(buf[1]);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
+ role->bounds = le32_to_cpu(buf[2]);
key = kmalloc(len + 1, GFP_KERNEL);
if (!key) {
@@ -1236,8 +1263,8 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
{
char *key = NULL;
struct type_datum *typdatum;
- int rc;
- __le32 buf[3];
+ int rc, to_read = 3;
+ __le32 buf[4];
u32 len;
typdatum = kzalloc(sizeof(*typdatum), GFP_KERNEL);
@@ -1246,13 +1273,27 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
return rc;
}
- rc = next_entry(buf, fp, sizeof buf);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
+ to_read = 4;
+
+ rc = next_entry(buf, fp, sizeof(buf[0]) * to_read);
if (rc < 0)
goto bad;
len = le32_to_cpu(buf[0]);
typdatum->value = le32_to_cpu(buf[1]);
- typdatum->primary = le32_to_cpu(buf[2]);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY) {
+ u32 prop = le32_to_cpu(buf[2]);
+
+ if (prop & TYPEDATUM_PROPERTY_PRIMARY)
+ typdatum->primary = 1;
+ if (prop & TYPEDATUM_PROPERTY_ATTRIBUTE)
+ typdatum->attribute = 1;
+
+ typdatum->bounds = le32_to_cpu(buf[3]);
+ } else {
+ typdatum->primary = le32_to_cpu(buf[2]);
+ }
key = kmalloc(len + 1, GFP_KERNEL);
if (!key) {
@@ -1309,8 +1350,8 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
{
char *key = NULL;
struct user_datum *usrdatum;
- int rc;
- __le32 buf[2];
+ int rc, to_read = 2;
+ __le32 buf[3];
u32 len;
usrdatum = kzalloc(sizeof(*usrdatum), GFP_KERNEL);
@@ -1319,12 +1360,17 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
goto out;
}
- rc = next_entry(buf, fp, sizeof buf);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
+ to_read = 3;
+
+ rc = next_entry(buf, fp, sizeof(buf[0]) * to_read);
if (rc < 0)
goto bad;
len = le32_to_cpu(buf[0]);
usrdatum->value = le32_to_cpu(buf[1]);
+ if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
+ usrdatum->bounds = le32_to_cpu(buf[2]);
key = kmalloc(len + 1, GFP_KERNEL);
if (!key) {
@@ -1465,6 +1511,133 @@ static int (*read_f[SYM_NUM]) (struct policydb *p, struct hashtab *h, void *fp)
cat_read,
};
+static int user_bounds_sanity_check(void *key, void *datum, void *datap)
+{
+ struct user_datum *upper, *user;
+ struct policydb *p = datap;
+ int depth = 0;
+
+ upper = user = datum;
+ while (upper->bounds) {
+ struct ebitmap_node *node;
+ unsigned long bit;
+
+ if (++depth == POLICYDB_BOUNDS_MAXDEPTH) {
+ printk(KERN_ERR "SELinux: user %s: "
+ "too deep or looped boundary",
+ (char *) key);
+ return -EINVAL;
+ }
+
+ upper = p->user_val_to_struct[upper->bounds - 1];
+ ebitmap_for_each_positive_bit(&user->roles, node, bit) {
+ if (ebitmap_get_bit(&upper->roles, bit))
+ continue;
+
+ printk(KERN_ERR
+ "SELinux: boundary violated policy: "
+ "user=%s role=%s bounds=%s\n",
+ p->p_user_val_to_name[user->value - 1],
+ p->p_role_val_to_name[bit],
+ p->p_user_val_to_name[upper->value - 1]);
+
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int role_bounds_sanity_check(void *key, void *datum, void *datap)
+{
+ struct role_datum *upper, *role;
+ struct policydb *p = datap;
+ int depth = 0;
+
+ upper = role = datum;
+ while (upper->bounds) {
+ struct ebitmap_node *node;
+ unsigned long bit;
+
+ if (++depth == POLICYDB_BOUNDS_MAXDEPTH) {
+ printk(KERN_ERR "SELinux: role %s: "
+ "too deep or looped bounds\n",
+ (char *) key);
+ return -EINVAL;
+ }
+
+ upper = p->role_val_to_struct[upper->bounds - 1];
+ ebitmap_for_each_positive_bit(&role->types, node, bit) {
+ if (ebitmap_get_bit(&upper->types, bit))
+ continue;
+
+ printk(KERN_ERR
+ "SELinux: boundary violated policy: "
+ "role=%s type=%s bounds=%s\n",
+ p->p_role_val_to_name[role->value - 1],
+ p->p_type_val_to_name[bit],
+ p->p_role_val_to_name[upper->value - 1]);
+
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int type_bounds_sanity_check(void *key, void *datum, void *datap)
+{
+ struct type_datum *upper, *type;
+ struct policydb *p = datap;
+ int depth = 0;
+
+ upper = type = datum;
+ while (upper->bounds) {
+ if (++depth == POLICYDB_BOUNDS_MAXDEPTH) {
+ printk(KERN_ERR "SELinux: type %s: "
+ "too deep or looped boundary\n",
+ (char *) key);
+ return -EINVAL;
+ }
+
+ upper = p->type_val_to_struct[upper->bounds - 1];
+ if (upper->attribute) {
+ printk(KERN_ERR "SELinux: type %s: "
+ "bounded by attribute %s",
+ (char *) key,
+ p->p_type_val_to_name[upper->value - 1]);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int policydb_bounds_sanity_check(struct policydb *p)
+{
+ int rc;
+
+ if (p->policyvers < POLICYDB_VERSION_BOUNDARY)
+ return 0;
+
+ rc = hashtab_map(p->p_users.table,
+ user_bounds_sanity_check, p);
+ if (rc)
+ return rc;
+
+ rc = hashtab_map(p->p_roles.table,
+ role_bounds_sanity_check, p);
+ if (rc)
+ return rc;
+
+ rc = hashtab_map(p->p_types.table,
+ type_bounds_sanity_check, p);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
extern int ss_initialized;
/*
@@ -1961,6 +2134,10 @@ int policydb_read(struct policydb *p, void *fp)
goto bad;
}
+ rc = policydb_bounds_sanity_check(p);
+ if (rc)
+ goto bad;
+
rc = 0;
out:
return rc;
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 4253370fda6a..55152d498b53 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -61,6 +61,7 @@ struct class_datum {
/* Role attributes */
struct role_datum {
u32 value; /* internal role value */
+ u32 bounds; /* boundary of role */
struct ebitmap dominates; /* set of roles dominated by this role */
struct ebitmap types; /* set of authorized types for role */
};
@@ -81,12 +82,15 @@ struct role_allow {
/* Type attributes */
struct type_datum {
u32 value; /* internal type value */
+ u32 bounds; /* boundary of type */
unsigned char primary; /* primary name? */
+ unsigned char attribute;/* attribute ?*/
};
/* User attributes */
struct user_datum {
u32 value; /* internal user value */
+ u32 bounds; /* bounds of user */
struct ebitmap roles; /* set of authorized roles for user */
struct mls_range range; /* MLS range (min - max) for user */
struct mls_level dfltlevel; /* default login MLS level for user */
@@ -209,6 +213,7 @@ struct policydb {
struct class_datum **class_val_to_struct;
struct role_datum **role_val_to_struct;
struct user_datum **user_val_to_struct;
+ struct type_datum **type_val_to_struct;
/* type enforcement access vectors and transitions */
struct avtab te_avtab;
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 5a0536bddc63..4f233d9960e7 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -88,6 +88,11 @@ static u32 latest_granting;
static int context_struct_to_string(struct context *context, char **scontext,
u32 *scontext_len);
+static int context_struct_compute_av(struct context *scontext,
+ struct context *tcontext,
+ u16 tclass,
+ u32 requested,
+ struct av_decision *avd);
/*
* Return the boolean value of a constraint expression
* when it is applied to the specified source and target
@@ -274,6 +279,100 @@ mls_ops:
}
/*
+ * security_boundary_permission - drops violated permissions
+ * on boundary constraint.
+ */
+static void type_attribute_bounds_av(struct context *scontext,
+ struct context *tcontext,
+ u16 tclass,
+ u32 requested,
+ struct av_decision *avd)
+{
+ struct context lo_scontext;
+ struct context lo_tcontext;
+ struct av_decision lo_avd;
+ struct type_datum *source
+ = policydb.type_val_to_struct[scontext->type - 1];
+ struct type_datum *target
+ = policydb.type_val_to_struct[tcontext->type - 1];
+ u32 masked = 0;
+
+ if (source->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+
+ memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
+ lo_scontext.type = source->bounds;
+
+ context_struct_compute_av(&lo_scontext,
+ tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (target->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+
+ memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
+ lo_tcontext.type = target->bounds;
+
+ context_struct_compute_av(scontext,
+ &lo_tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (source->bounds && target->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+ /*
+ * lo_scontext and lo_tcontext are already
+ * set up.
+ */
+
+ context_struct_compute_av(&lo_scontext,
+ &lo_tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (masked) {
+ struct audit_buffer *ab;
+ char *stype_name
+ = policydb.p_type_val_to_name[source->value - 1];
+ char *ttype_name
+ = policydb.p_type_val_to_name[target->value - 1];
+ char *tclass_name
+ = policydb.p_class_val_to_name[tclass - 1];
+
+ /* mask violated permissions */
+ avd->allowed &= ~masked;
+
+ /* notice to userspace via audit message */
+ ab = audit_log_start(current->audit_context,
+ GFP_ATOMIC, AUDIT_SELINUX_ERR);
+ if (!ab)
+ return;
+
+ audit_log_format(ab, "av boundary violation: "
+ "source=%s target=%s tclass=%s",
+ stype_name, ttype_name, tclass_name);
+ avc_dump_av(ab, tclass, masked);
+ audit_log_end(ab);
+ }
+}
+
+/*
* Compute access vectors based on a context structure pair for
* the permissions in a particular class.
*/
@@ -404,6 +503,14 @@ static int context_struct_compute_av(struct context *scontext,
PROCESS__DYNTRANSITION);
}
+ /*
+ * If the given source and target types have boundary
+ * constraint, lazy checks have to mask any violated
+ * permission and notice it to userspace via audit.
+ */
+ type_attribute_bounds_av(scontext, tcontext,
+ tclass, requested, avd);
+
return 0;
inval_class:
@@ -549,6 +656,69 @@ out:
return rc;
}
+/*
+ * security_bounded_transition - check whether the given
+ * transition is directed to bounded, or not.
+ * It returns 0, if @newsid is bounded by @oldsid.
+ * Otherwise, it returns error code.
+ *
+ * @oldsid : current security identifier
+ * @newsid : destinated security identifier
+ */
+int security_bounded_transition(u32 old_sid, u32 new_sid)
+{
+ struct context *old_context, *new_context;
+ struct type_datum *type;
+ int index;
+ int rc = -EINVAL;
+
+ read_lock(&policy_rwlock);
+
+ old_context = sidtab_search(&sidtab, old_sid);
+ if (!old_context) {
+ printk(KERN_ERR "SELinux: %s: unrecognized SID %u\n",
+ __func__, old_sid);
+ goto out;
+ }
+
+ new_context = sidtab_search(&sidtab, new_sid);
+ if (!new_context) {
+ printk(KERN_ERR "SELinux: %s: unrecognized SID %u\n",
+ __func__, new_sid);
+ goto out;
+ }
+
+ /* type/domain unchaned */
+ if (old_context->type == new_context->type) {
+ rc = 0;
+ goto out;
+ }
+
+ index = new_context->type;
+ while (true) {
+ type = policydb.type_val_to_struct[index - 1];
+ BUG_ON(!type);
+
+ /* not bounded anymore */
+ if (!type->bounds) {
+ rc = -EPERM;
+ break;
+ }
+
+ /* @newsid is bounded by @oldsid */
+ if (type->bounds == old_context->type) {
+ rc = 0;
+ break;
+ }
+ index = type->bounds;
+ }
+out:
+ read_unlock(&policy_rwlock);
+
+ return rc;
+}
+
+
/**
* security_compute_av - Compute access vector decisions.
* @ssid: source security identifier
@@ -794,7 +964,7 @@ static int string_to_context_struct(struct policydb *pol,
*p++ = 0;
typdatum = hashtab_search(pol->p_types.table, scontextp);
- if (!typdatum)
+ if (!typdatum || typdatum->attribute)
goto out;
ctx->type = typdatum->value;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.