/* * Implementation of the security services. * * Authors : Stephen Smalley, * James Morris * * Updated: Trusted Computer Solutions, Inc. * * Support for enhanced MLS infrastructure. * * Updated: Frank Mayer and Karl MacMillan * * Added conditional policy language extensions * * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc. * Copyright (C) 2003 - 2004 Tresys Technology, LLC * Copyright (C) 2003 Red Hat, Inc., James Morris * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, version 2. */ #include #include #include #include #include #include #include #include #include #include "flask.h" #include "avc.h" #include "avc_ss.h" #include "security.h" #include "context.h" #include "policydb.h" #include "sidtab.h" #include "services.h" #include "conditional.h" #include "mls.h" extern void selnl_notify_policyload(u32 seqno); unsigned int policydb_loaded_version; static DEFINE_RWLOCK(policy_rwlock); #define POLICY_RDLOCK read_lock(&policy_rwlock) #define POLICY_WRLOCK write_lock_irq(&policy_rwlock) #define POLICY_RDUNLOCK read_unlock(&policy_rwlock) #define POLICY_WRUNLOCK write_unlock_irq(&policy_rwlock) static DECLARE_MUTEX(load_sem); #define LOAD_LOCK down(&load_sem) #define LOAD_UNLOCK up(&load_sem) static struct sidtab sidtab; struct policydb policydb; int ss_initialized = 0; /* * The largest sequence number that has been used when * providing an access decision to the access vector cache. * The sequence number only changes when a policy change * occurs. */ static u32 latest_granting = 0; /* Forward declaration. */ static int context_struct_to_string(struct context *context, char **scontext, u32 *scontext_len); /* * 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. */ static int constraint_expr_eval(struct context *scontext, struct context *tcontext, struct context *xcontext, struct constraint_expr *cexpr) { u32 val1, val2; struct context *c; struct role_datum *r1, *r2; struct mls_level *l1, *l2; struct constraint_expr *e; int s[CEXPR_MAXDEPTH]; int sp = -1; for (e = cexpr; e; e = e->next) { switch (e->expr_type) { case CEXPR_NOT: BUG_ON(sp < 0); s[sp] = !s[sp]; break; case CEXPR_AND: BUG_ON(sp < 1); sp--; s[sp] &= s[sp+1]; break; case CEXPR_OR: BUG_ON(sp < 1); sp--; s[sp] |= s[sp+1]; break; case CEXPR_ATTR: if (sp == (CEXPR_MAXDEPTH-1)) return 0; switch (e->attr) { case CEXPR_USER: val1 = scontext->user; val2 = tcontext->user; break; case CEXPR_TYPE: val1 = scontext->type; val2 = tcontext->type; 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]; switch (e->op) { case CEXPR_DOM: s[++sp] = ebitmap_get_bit(&r1->dominates, val2 - 1); continue; case CEXPR_DOMBY: s[++sp] = ebitmap_get_bit(&r2->dominates, val1 - 1); continue; case CEXPR_INCOMP: s[++sp] = ( !ebitmap_get_bit(&r1->dominates, val2 - 1) && !ebitmap_get_bit(&r2->dominates, val1 - 1) ); continue; default: break; } break; case CEXPR_L1L2: l1 = &(scontext->range.level[0]); l2 = &(tcontext->range.level[0]); goto mls_ops; case CEXPR_L1H2: l1 = &(scontext->range.level[0]); l2 = &(tcontext->range.level[1]); goto mls_ops; case CEXPR_H1L2: l1 = &(scontext->range.level[1]); l2 = &(tcontext->range.level[0]); goto mls_ops; case CEXPR_H1H2: l1 = &(scontext->range.level[1]); l2 = &(tcontext->range.level[1]); goto mls_ops; case CEXPR_L1H1: l1 = &(scontext->range.level[0]); l2 = &(scontext->range.level[1]); goto mls_ops; case CEXPR_L2H2: l1 = &(tcontext->range.level[0]); l2 = &(tcontext->range.level[1]); goto mls_ops; mls_ops: switch (e->op) { case CEXPR_EQ: s[++sp] = mls_level_eq(l1, l2); continue; case CEXPR_NEQ: s[++sp] = !mls_level_eq(l1, l2); continue; case CEXPR_DOM: s[++sp] = mls_level_dom(l1, l2); continue; case CEXPR_DOMBY: s[++sp] = mls_level_dom(l2, l1); continue; case CEXPR_INCOMP: s[++sp] = mls_level_incomp(l2, l1); continue; default: BUG(); return 0; } break; default: BUG(); return 0; } switch (e->op) { case CEXPR_EQ: s[++sp] = (val1 == val2); break; case CEXPR_NEQ: s[++sp] = (val1 != val2); break; default: BUG(); return 0; } break; case CEXPR_NAMES: if (sp == (CEXPR_MAXDEPTH-1)) return 0; c = scontext; if (e->attr & CEXPR_TARGET) c = tcontext; else if (e->attr & CEXPR_XTARGET) { c = xcontext; if (!c) { BUG(); return 0; } } if (e->attr & CEXPR_USER) val1 = c->user; else if (e->attr & CEXPR_ROLE) val1 = c->role; else if (e->attr & CEXPR_TYPE) val1 = c->type; else { BUG(); return 0; } switch (e->op) { case CEXPR_EQ: s[++sp] = ebitmap_get_bit(&e->names, val1 - 1); break; case CEXPR_NEQ: s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1); break; default: BUG(); return 0; } break; default: BUG(); return 0; } } BUG_ON(sp != 0); return s[0]; } /* * Compute access vectors based on a context structure pair for * the permissions in a particular class. */ static int context_struct_compute_av(struct context *scontext, struct context *tcontext, u16 tclass, u32 requested, struct av_decision *avd) { struct constraint_node *constraint; struct role_allow *ra; struct avtab_key avkey; struct avtab_node *node; struct class_datum *tclass_datum; struct ebitmap *sattr, *tattr; struct ebitmap_node *snode, *tnode; unsigned int i, j; /* * Remap extended Netlink classes for old policy versions. * Do this here rather than socket_type_to_security_class() * in case a newer policy version is loaded, allowing sockets * to remain in the correct class. */ if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS) if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET && tclass <= SECCLASS_NETLINK_DNRT_SOCKET) tclass = SECCLASS_NETLINK_SOCKET; if (!tclass || tclass > policydb.p_classes.nprim) { printk(KERN_ERR "security_compute_av: unrecognized class %d\n", tclass); return -EINVAL; } tclass_datum = policydb.class_val_to_struct[tclass - 1]; /* * Initialize the access vectors to the default values. */ avd->allowed = 0; avd->decided = 0xffffffff; avd->auditallow = 0; avd->auditdeny = 0xffffffff; avd->seqno = latest_granting; /* * If a specific type enforcement rule was defined for * this permission check, then use it. */ avkey.target_class = tclass; avkey.specified = AVTAB_AV; sattr = &policydb.type_attr_map[scontext->type - 1]; tattr = &policydb.type_attr_map[tcontext->type - 1]; ebitmap_for_each_bit(sattr, snode, i) { if (!ebitmap_node_get_bit(snode, i)) continue; ebitmap_for_each_bit(tattr, tnode, j) { if (!ebitmap_node_get_bit(tnode, j)) continue; avkey.source_type = i + 1; avkey.target_type = j + 1; for (node = avtab_search_node(&policydb.te_avtab, &avkey); node != NULL; node = avtab_search_node_next(node, avkey.specified)) { if (node->key.specified == AVTAB_ALLOWED) avd->allowed |= node->datum.data; else if (node->key.specified == AVTAB_AUDITALLOW) avd->auditallow |= node->datum.data; else if (node->key.specified == AVTAB_AUDITDENY) avd->auditdeny &= node->datum.data; } /* Check conditional av table for additional permissions */ cond_compute_av(&policydb.te_cond_avtab, &avkey, avd); } } /* * Remove any permissions prohibited by a constraint (this includes * the MLS policy). */ constraint = tclass_datum->constraints; while (constraint) { if ((constraint->permissions & (avd->allowed)) && !constraint_expr_eval(scontext, tcontext, NULL, constraint->expr)) { avd->allowed = (avd->allowed) & ~(constraint->permissions); } constraint = constraint->next; } /* * If checking process transition permission and the * role is changing, then check the (current_role, new_role) * pair. */ if (tclass == SECCLASS_PROCESS && (avd->allowed & (PROCESS__TRANSITION | PROCESS__DYNTRANSITION)) && scontext->role != tcontext->role) { for (ra = policydb.role_allow; ra; ra = ra->next) { if (scontext->role == ra->role && tcontext->role == ra->new_role) break; } if (!ra) avd->allowed = (avd->allowed) & ~(PROCESS__TRANSITION | PROCESS__DYNTRANSITION); } return 0; } static int security_validtrans_handle_fail(struct context *ocontext, struct context *ncontext, struct context *tcontext, u16 tclass) { char *o = NULL, *n = NULL, *t = NULL; u32 olen, nlen, tlen; if (context_struct_to_string(ocontext, &o, &olen) < 0) goto out; if (context_struct_to_string(ncontext, &n, &nlen) < 0) goto out; if (context_struct_to_string(tcontext, &t, &tlen) < 0) goto out; audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR, "security_validate_transition: denied for" " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s", o, n, t, policydb.p_class_val_to_name[tclass-1]); out: kfree(o); kfree(n); kfree(t); if (!selinux_enforcing) return 0; return -EPERM; } int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid, u16 tclass) { struct context *ocontext; struct context *ncontext; struct context *tcontext; struct class_datum *tclass_datum; struct constraint_node *constraint; int rc = 0; if (!ss_initialized) return 0; POLICY_RDLOCK; /* * Remap extended Netlink classes for old policy versions. * Do this here rather than socket_type_to_security_class() * in case a newer policy version is loaded, allowing sockets * to remain in the correct class. */ if (policydb_loaded_version < POLICYDB_VERSION_NLCLASS) if (tclass >= SECCLASS_NETLINK_ROUTE_SOCKET && tclass <= SECCLASS_NETLINK_DNRT_SOCKET) tclass = SECCLASS_NETLINK_SOCKET; if (!tclass || tclass > policydb.p_classes.nprim) { printk(KERN_ERR "security_validate_transition: " "unrecognized class %d\n", tclass); rc = -EINVAL; goto out; } tclass_datum = policydb.class_val_to_struct[tclass - 1]; ocontext = sidtab_search(&sidtab, oldsid); if (!ocontext) { printk(KERN_ERR "security_validate_transition: " " unrecognized SID %d\n", oldsid); rc = -EINVAL; goto out; } ncontext = sidtab_search(&sidtab, newsid); if (!ncontext) { printk(KERN_ERR "security_validate_transition: " " unrecognized SID %d\n", newsid); rc = -EINVAL; goto out; } tcontext = sidtab_search(&sidtab, tasksid); if (!tcontext) { printk(KERN_ERR "security_validate_transition: " " unrecognized SID %d\n", tasksid); rc = -EINVAL; goto out; } constraint = tclass_datum->validatetrans; while (constraint) { if (!constraint_expr_eval(ocontext, ncontext, tcontext, constraint->expr)) { rc = security_validtrans_handle_fail(ocontext, ncontext, tcontext, tclass); goto out; } constraint = constraint->next; } out: POLICY_RDUNLOCK; return rc; } /** * security_compute_av - Compute access vector decisions. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions * @avd: access vector decisions * * Compute a set of access vector decisions based on the * SID pair (@ssid, @tsid) for the permissions in @tclass. * Return -%EINVAL if any of the parameters are invalid or %0 * if the access vector decisions were computed successfully. */ int security_compute_av(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct av_decision *avd) { struct context *scontext = NULL, *tcontext = NULL; int rc = 0; if (!ss_initialized) { avd->allowed = 0xffffffff; avd->decided = 0xffffffff; avd->auditallow = 0; avd->auditdeny = 0xffffffff; avd->seqno = latest_granting; return 0; } POLICY_RDLOCK; scontext = sidtab_search(&sidtab, ssid); if (!scontext) { printk(KERN_ERR "security_compute_av: unrecognized SID %d\n", ssid); rc = -EINVAL; goto out; } tcontext = sidtab_search(&sidtab, tsid); if (!tcontext) { printk(KERN_ERR "security_compute_av: unrecognized SID %d\n", tsid); rc = -EINVAL; goto out; } rc = context_struct_compute_av(scontext, tcontext, tclass, requested, avd); out: POLICY_RDUNLOCK; return rc; } /* * Write the security context string representation of * the context structure `context' into a dynamically * allocated string of the correct size. Set `*scontext' * to point to this string and set `*scontext_len' to * the length of the string. */ static int context_struct_to_string(struct context *context, char **scontext, u32 *scontext_len) { char *scontextp; *scontext = NULL; *scontext_len = 0; /* Compute the size of the context. */ *scontext_len += strlen(policydb.p_user_val_to_name[context->user - 1]) + 1; *scontext_len += strlen(policydb.p_role_val_to_name[context->role - 1]) + 1; *scontext_len += strlen(policydb.p_type_val_to_name[context->type - 1]) + 1; *scontext_len += mls_compute_context_len(context); /* Allocate space for the context; caller must free this space. */ scontextp = kmalloc(*scontext_len, GFP_ATOMIC); if (!scontextp) { return -ENOMEM; } *scontext = scontextp; /* * Copy the user name, role name and type name into the context. */ sprintf(scontextp, "%s:%s:%s", policydb.p_user_val_to_name[context->user - 1], policydb.p_role_val_to_name[context->role - 1], policydb.p_type_val_to_name[context->type - 1]); scontextp += strlen(policydb.p_user_val_to_name[context->user - 1]) + 1 + strlen(policydb.p_role_val_to_name[context->role - 1]) + 1 + strlen(policydb.p_type_val_to_name[context->type - 1]); mls_sid_to_context(context, &scontextp); *scontextp = 0; return 0; } #include "initial_sid_to_string.h" /** * security_sid_to_context - Obtain a context for a given SID. * @sid: security identifier, SID * @scontext: security context * @scontext_len: length in bytes * * Write the string representation of the context associated with @sid * into a dynamically allocated string of the correct size. Set @scontext * to point to this string and set @scontext_len to the length of the string. */ int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len) { struct context *context; int rc = 0; if (!ss_initialized) { if (sid <= SECINITSID_NUM) { char *scontextp; *scontext_len = strlen(initial_sid_to_string[sid]) + 1; scontextp = kmalloc(*scontext_len,GFP_ATOMIC); strcpy(scontextp, initial_sid_to_string[sid]); *scontext = scontextp; goto out; } printk(KERN_ERR "security_sid_to_context: called before initial " "load_policy on unknown SID %d\n", sid); rc = -EINVAL; goto out; } POLICY_RDLOCK; context = sidtab_search(&sidtab, sid); if (!context) { printk(KERN_ERR "security_sid_to_context: unrecognized SID " "%d\n", sid); rc = -EINVAL; goto out_unlock; } rc = context_struct_to_string(context, scontext, scontext_len); out_unlock: POLICY_RDUNLOCK; out: return rc; } static int security_context_to_sid_core(char *scontext, u32 scontext_len, u32 *sid, u32 def_sid) { char *scontext2; struct context context; struct role_datum *role; struct type_datum *typdatum; struct user_datum *usrdatum; char *scontextp, *p, oldc; int rc = 0; if (!ss_initialized) { int i; for (i = 1; i < SECINITSID_NUM; i++) { if (!strcmp(initial_sid_to_string[i], scontext)) { *sid = i; goto out; } } *sid = SECINITSID_KERNEL; goto out; } *sid = SECSID_NULL; /* Copy the string so that we can modify the copy as we parse it. The string should already by null terminated, but we append a null suffix to the copy to avoid problems with the existing attr package, which doesn't view the null terminator as part of the attribute value. */ scontext2 = kmalloc(scontext_len+1,GFP_KERNEL); if (!scontext2) { rc = -ENOMEM; goto out; } memcpy(scontext2, scontext, scontext_len); scontext2[scontext_len] = 0; context_init(&context); *sid = SECSID_NULL; POLICY_RDLOCK; /* Parse the security context. */ rc = -EINVAL; scontextp = (char *) scontext2; /* Extract the user. */ p = scontextp; while (*p && *p != ':') p++; if (*p == 0) goto out_unlock; *p++ = 0; usrdatum = hashtab_search(policydb.p_users.table, scontextp); if (!usrdatum) goto out_unlock; context.user = usrdatum->value; /* Extract role. */ scontextp = p; while (*p && *p != ':') p++; if (*p == 0) goto out_unlock; *p++ = 0; role = hashtab_search(policydb.p_roles.table, scontextp); if (!role) goto out_unlock; context.role = role->value; /* Extract type. */ scontextp = p; while (*p && *p != ':') p++; oldc = *p; *p++ = 0; typdatum = hashtab_search(policydb.p_types.table, scontextp); if (!typdatum) goto out_unlock; context.type = typdatum->value; rc = mls_context_to_sid(oldc, &p, &context, &sidtab, def_sid); if (rc) goto out_unlock; if ((p - scontext2) < scontext_len) { rc = -EINVAL; goto out_unlock; } /* Check the validity of the new context. */ if (!policydb_context_isvalid(&policydb, &context)) { rc = -EINVAL; goto out_unlock; } /* Obtain the new sid. */ rc = sidtab_context_to_sid(&sidtab, &context, sid); out_unlock: POLICY_RDUNLOCK; context_destroy(&context); kfree(scontext2); out: return rc; } /** * security_context_to_sid - Obtain a SID for a given security context. * @scontext: security context * @scontext_len: length in bytes * @sid: security identifier, SID * * Obtains a SID associated with the security context that * has the string representation specified by @scontext. * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient * memory is available, or 0 on success. */ int security_context_to_sid(char *scontext, u32 scontext_len, u32 *sid) { return security_context_to_sid_core(scontext, scontext_len, sid, SECSID_NULL); } /** * security_context_to_sid_default - Obtain a SID for a given security context, * falling back to specified default if needed. * * @scontext: security context * @scontext_len: length in bytes * @sid: security identifier, SID * @def_sid: default SID to assign on errror * * Obtains a SID associated with the security context that * has the string representation specified by @scontext. * The default SID is passed to the MLS layer to be used to allow * kernel labeling of the MLS field if the MLS field is not present * (for upgrading to MLS without full relabel). * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient * memory is available, or 0 on success. */ int security_context_to_sid_default(char *scontext, u32 scontext_len, u32 *sid, u32 def_sid) { return security_context_to_sid_core(scontext, scontext_len, sid, def_sid); } static int compute_sid_handle_invalid_context( struct context *scontext, struct context *tcontext, u16 tclass, struct context *newcontext) { char *s = NULL, *t = NULL, *n = NULL; u32 slen, tlen, nlen; if (context_struct_to_string(scontext, &s, &slen) < 0) goto out; if (context_struct_to_string(tcontext, &t, &tlen) < 0) goto out; if (context_struct_to_string(newcontext, &n, &nlen) < 0) goto out; audit_log(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR, "security_compute_sid: invalid context %s" " for scontext=%s" " tcontext=%s" " tclass=%s", n, s, t, policydb.p_class_val_to_name[tclass-1]); out: kfree(s); kfree(t); kfree(n); if (!selinux_enforcing) return 0; return -EACCES; } static int security_compute_sid(u32 ssid, u32 tsid, u16 tclass, u32 specified, u32 *out_sid) { struct context *scontext = NULL, *tcontext = NULL, newcontext; struct role_trans *roletr = NULL; struct avtab_key avkey; struct avtab_datum *avdatum; struct avtab_node *node; int rc = 0; if (!ss_initialized) { switch (tclass) { case SECCLASS_PROCESS: *out_sid = ssid; break; default: *out_sid = tsid; break; } goto out; } POLICY_RDLOCK; scontext = sidtab_search(&sidtab, ssid); if (!scontext) { printk(KERN_ERR "security_compute_sid: unrecognized SID %d\n", ssid); rc = -EINVAL; goto out_unlock; } tcontext = sidtab_search(&sidtab, tsid); if (!tcontext) { printk(KERN_ERR "security_compute_sid: unrecognized SID %d\n", tsid); rc = -EINVAL; goto out_unlock; } context_init(&newcontext); /* Set the user identity. */ switch (specified) { case AVTAB_TRANSITION: case AVTAB_CHANGE: /* Use the process user identity. */ newcontext.user = scontext->user; break; case AVTAB_MEMBER: /* Use the related object owner. */ newcontext.user = tcontext->user; break; } /* Set the role and type to default values. */ switch (tclass) { case SECCLASS_PROCESS: /* Use the current role and type of process. */ newcontext.role = scontext->role; newcontext.type = scontext->type; break; default: /* Use the well-defined object role. */ newcontext.role = OBJECT_R_VAL; /* Use the type of the related object. */ newcontext.type = tcontext->type; } /* Look for a type transition/member/change rule. */ avkey.source_type = scontext->type; avkey.target_type = tcontext->type; avkey.target_class = tclass; avkey.specified = specified; avdatum = avtab_search(&policydb.te_avtab, &avkey); /* If no permanent rule, also check for enabled conditional rules */ if(!avdatum) { node = avtab_search_node(&policydb.te_cond_avtab, &avkey); for (; node != NULL; node = avtab_search_node_next(node, specified)) { if (node->key.specified & AVTAB_ENABLED) { avdatum = &node->datum; break; } } } if (avdatum) { /* Use the type from the type transition/member/change rule. */ newcontext.type = avdatum->data; } /* Check for class-specific changes. */ switch (tclass) { case SECCLASS_PROCESS: if (specified & AVTAB_TRANSITION) { /* Look for a role transition rule. */ for (roletr = policydb.role_tr; roletr; roletr = roletr->next) { if (roletr->role == scontext->role && roletr->type == tcontext->type) { /* Use the role transition rule. */ newcontext.role = roletr->new_role; break; } } } break; default: break; } /* Set the MLS attributes. This is done last because it may allocate memory. */ rc = mls_compute_sid(scontext, tcontext, tclass, specified, &newcontext); if (rc) goto out_unlock; /* Check the validity of the context. */ if (!policydb_context_isvalid(&policydb, &newcontext)) { rc = compute_sid_handle_invalid_context(scontext, tcontext, tclass, &newcontext); if (rc) goto out_unlock; } /* Obtain the sid for the context. */ rc = sidtab_context_to_sid(&sidtab, &newcontext, out_sid); out_unlock: POLICY_RDUNLOCK; context_destroy(&newcontext); out: return rc; } /** * security_transition_sid - Compute the SID for a new subject/object. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @out_sid: security identifier for new subject/object * * Compute a SID to use for labeling a new subject or object in the * class @tclass based on a SID pair (@ssid, @tsid). * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM * if insufficient memory is available, or %0 if the new SID was * computed successfully. */ int security_transition_sid(u32 ssid, u32 tsid, u16 tclass, u32 *out_sid) { return security_compute_sid(ssid, tsid, tclass, AVTAB_TRANSITION, out_sid); } /** * security_member_sid - Compute the SID for member selection. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @out_sid: security identifier for selected member * * Compute a SID to use when selecting a member of a polyinstantiated * object of class @tclass based on a SID pair (@ssid, @tsid). * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM * if insufficient memory is available, or %0 if the SID was * computed successfully. */ int security_member_sid(u32 ssid, u32 tsid, u16 tclass, u32 *out_sid) { return security_compute_sid(ssid, tsid, tclass, AVTAB_MEMBER, out_sid); } /** * security_change_sid - Compute the SID for object relabeling. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @out_sid: security identifier for selected member * * Compute a SID to use for relabeling an object of class @tclass * based on a SID pair (@ssid, @tsid). * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM * if insufficient memory is available, or %0 if the SID was * computed successfully. */ int security_change_sid(u32 ssid, u32 tsid, u16 tclass, u32 *out_sid) { return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, out_sid); } /* * Verify that each permission that is defined under the * existing policy is still defined with the same value * in the new policy. */ static int validate_perm(void *key, void *datum, void *p) { struct hashtab *h; struct perm_datum *perdatum, *perdatum2; int rc = 0; h = p; perdatum = datum; perdatum2 = hashtab_search(h, key); if (!perdatum2) { printk(KERN_ERR "security: permission %s disappeared", (char *)key); rc = -ENOENT; goto out; } if (perdatum->value != perdatum2->value) { printk(KERN_ERR "security: the value of permission %s changed", (char *)key); rc = -EINVAL; } out: return rc; } /* * Verify that each class that is defined under the * existing policy is still defined with the same * attributes in the new policy. */ static int validate_class(void *key, void *datum, void *p) { struct policydb *newp; struct class_datum *cladatum, *cladatum2; int rc; newp = p; cladatum = datum; cladatum2 = hashtab_search(newp->p_classes.table, key); if (!cladatum2) { printk(KERN_ERR "security: class %s disappeared\n", (char *)key); rc = -ENOENT; goto out; } if (cladatum->value != cladatum2->value) { printk(KERN_ERR "security: the value of class %s changed\n", (char *)key); rc = -EINVAL; goto out; } if ((cladatum->comdatum && !cladatum2->comdatum) || (!cladatum->comdatum && cladatum2->comdatum)) { printk(KERN_ERR "security: the inherits clause for the access " "vector definition for class %s changed\n", (char *)key); rc = -EINVAL; goto out; } if (cladatum->comdatum) { rc = hashtab_map(cladatum->comdatum->permissions.table, validate_perm, cladatum2->comdatum->permissions.table); if (rc) { printk(" in the access vector definition for class " "%s\n", (char *)key); goto out; } } rc = hashtab_map(cladatum->permissions.table, validate_perm, cladatum2->permissions.table); if (rc) printk(" in access vector definition for class %s\n", (char *)key); out: return rc; } /* Clone the SID into the new SID table. */ static int clone_sid(u32 sid, struct context *context, void *arg) { struct sidtab *s = arg; return sidtab_insert(s, sid, context); } static inline int convert_context_handle_invalid_context(struct context *context) { int rc = 0; if (selinux_enforcing) { rc = -EINVAL; } else { char *s; u32 len; context_struct_to_string(context, &s, &len); printk(KERN_ERR "security: context %s is invalid\n", s); kfree(s); } return rc; } struct convert_context_args { struct policydb *oldp; struct policydb *newp; }; /* * Convert the values in the security context * structure `c' from the values specified * in the policy `p->oldp' to the values specified * in the policy `p->newp'. Verify that the * context is valid under the new policy. */ static int convert_context(u32 key, struct context *c, void *p) { struct convert_context_args *args; struct context oldc; struct role_datum *role; struct type_datum *typdatum; struct user_datum *usrdatum; char *s; u32 len; int rc; args = p; rc = context_cpy(&oldc, c); if (rc) goto out; rc = -EINVAL; /* Convert the user. */ usrdatum = hashtab_search(args->newp->p_users.table, args->oldp->p_user_val_to_name[c->user - 1]); if (!usrdatum) { goto bad; } c->user = usrdatum->value; /* Convert the role. */ role = hashtab_search(args->newp->p_roles.table, args->oldp->p_role_val_to_name[c->role - 1]); if (!role) { goto bad; } c->role = role->value; /* Convert the type. */ typdatum = hashtab_search(args->newp->p_types.table, args->oldp->p_type_val_to_name[c->type - 1]); if (!typdatum) { goto bad; } c->type = typdatum->value; rc = mls_convert_context(args->oldp, args->newp, c); if (rc) goto bad; /* Check the validity of the new context. */ if (!policydb_context_isvalid(args->newp, c)) { rc = convert_context_handle_invalid_context(&oldc); if (rc) goto bad; } context_destroy(&oldc); out: return rc; bad: context_struct_to_string(&oldc, &s, &len); context_destroy(&oldc); printk(KERN_ERR "security: invalidating context %s\n", s); kfree(s); goto out; } extern void selinux_complete_init(void); /** * security_load_policy - Load a security policy configuration. * @data: binary policy data * @len: length of data in bytes * * Load a new set of security policy configuration data, * validate it and convert the SID table as necessary. * This function will flush the access vector cache after * loading the new policy. */ int security_load_policy(void *data, size_t len) { struct policydb oldpolicydb, newpolicydb; struct sidtab oldsidtab, newsidtab; struct convert_context_args args; u32 seqno; int rc = 0; struct policy_file file = { data, len }, *fp = &file; LOAD_LOCK; if (!ss_initialized) { avtab_cache_init(); if (policydb_read(&policydb, fp)) { LOAD_UNLOCK; avtab_cache_destroy(); return -EINVAL; } if (policydb_load_isids(&policydb, &sidtab)) { LOAD_UNLOCK; policydb_destroy(&policydb); avtab_cache_destroy(); return -EINVAL; } policydb_loaded_version = policydb.policyvers; ss_initialized = 1; seqno = ++latest_granting; LOAD_UNLOCK; selinux_complete_init(); avc_ss_reset(seqno); selnl_notify_policyload(seqno); return 0; } #if 0 sidtab_hash_eval(&sidtab, "sids"); #endif if (policydb_read(&newpolicydb, fp)) { LOAD_UNLOCK; return -EINVAL; } sidtab_init(&newsidtab); /* Verify that the existing classes did not change. */ if (hashtab_map(policydb.p_classes.table, validate_class, &newpolicydb)) { printk(KERN_ERR "security: the definition of an existing " "class changed\n"); rc = -EINVAL; goto err; } /* Clone the SID table. */ sidtab_shutdown(&sidtab); if (sidtab_map(&sidtab, clone_sid, &newsidtab)) { rc = -ENOMEM; goto err; } /* Convert the internal representations of contexts in the new SID table and remove invalid SIDs. */ args.oldp = &policydb; args.newp = &newpolicydb; sidtab_map_remove_on_error(&newsidtab, convert_context, &args); /* Save the old policydb and SID table to free later. */ memcpy(&oldpolicydb, &policydb, sizeof policydb); sidtab_set(&oldsidtab, &sidtab); /* Install the new policydb and SID table. */ POLICY_WRLOCK; memcpy(&policydb, &newpolicydb, sizeof policydb); sidtab_set(&sidtab, &newsidtab); seqno = ++latest_granting; policydb_loaded_version = policydb.policyvers; POLICY_WRUNLOCK; LOAD_UNLOCK; /* Free the old policydb and SID table. */ policydb_destroy(&oldpolicydb); sidtab_destroy(&oldsidtab); avc_ss_reset(seqno); selnl_notify_policyload(seqno); return 0; err: LOAD_UNLOCK; sidtab_destroy(&newsidtab); policydb_destroy(&newpolicydb); return rc; } /** * security_port_sid - Obtain the SID for a port. * @domain: communication domain aka address family * @type: socket type * @protocol: protocol number * @port: port number * @out_sid: security identifier */ int security_port_sid(u16 domain, u16 type, u8 protocol, u16 port, u32 *out_sid) { struct ocontext *c; int rc = 0; POLICY_RDLOCK; c = policydb.ocontexts[OCON_PORT]; while (c) { if (c->u.port.protocol == protocol && c->u.port.low_port <= port && c->u.port.high_port >= port) break; c = c->next; } if (c) { if (!c->sid[0]) { rc = sidtab_context_to_sid(&sidtab, &c->context[0], &c->sid[0]); if (rc) goto out; } *out_sid = c->sid[0]; } else { *out_sid = SECINITSID_PORT; } out: POLICY_RDUNLOCK; return rc; } /** * security_netif_sid - Obtain the SID for a network interface. * @name: interface name * @if_sid: interface SID * @msg_sid: default SID for received packets */ int security_netif_sid(char *name, u32 *if_sid, u32 *msg_sid) { int rc = 0; struct ocontext *c; POLICY_RDLOCK; c = policydb.ocontexts[OCON_NETIF]; while (c) { if (strcmp(name, c->u.name) == 0) break; c = c->next; } if (c) { if (!c->sid[0] || !c->sid[1]) { rc = sidtab_context_to_sid(&sidtab, &c->context[0], &c->sid[0]); if (rc) goto out; rc = sidtab_context_to_sid(&sidtab, &c->context[1], &c->sid[1]); if (rc) goto out; } *if_sid = c->sid[0]; *msg_sid = c->sid[1]; } else { *if_sid = SECINITSID_NETIF; *msg_sid = SECINITSID_NETMSG; } out: POLICY_RDUNLOCK; return rc; } static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask) { int i, fail = 0; for(i = 0; i < 4; i++) if(addr[i] != (input[i] & mask[i])) { fail = 1; break; } return !fail; } /** * security_node_sid - Obtain the SID for a node (host). * @domain: communication domain aka address family * @addrp: address * @addrlen: address length in bytes * @out_sid: security identifier */ int security_node_sid(u16 domain, void *addrp, u32 addrlen, u32 *out_sid) { int rc = 0; struct ocontext *c; POLICY_RDLOCK; switch (domain) { case AF_INET: { u32 addr; if (addrlen != sizeof(u32)) { rc = -EINVAL; goto out; } addr = *((u32 *)addrp); c = policydb.ocontexts[OCON_NODE]; while (c) { if (c->u.node.addr == (addr & c->u.node.mask)) break; c = c->next; } break; } case AF_INET6: if (addrlen != sizeof(u64) * 2) { rc = -EINVAL; goto out; } c = policydb.ocontexts[OCON_NODE6]; while (c) { if (match_ipv6_addrmask(addrp, c->u.node6.addr, c->u.node6.mask)) break; c = c->next; } break; default: *out_sid = SECINITSID_NODE; goto out; } if (c) { if (!c->sid[0]) { rc = sidtab_context_to_sid(&sidtab, &c->context[0], &c->sid[0]); if (rc) goto out; } *out_sid = c->sid[0]; } else { *out_sid = SECINITSID_NODE; } out: POLICY_RDUNLOCK; return rc; } #define SIDS_NEL 25 /** * security_get_user_sids - Obtain reachable SIDs for a user. * @fromsid: starting SID * @username: username * @sids: array of reachable SIDs for user * @nel: number of elements in @sids * * Generate the set of SIDs for legal security contexts * for a given user that can be reached by @fromsid. * Set *@sids to point to a dynamically allocated * array containing the set of SIDs. Set *@nel to the * number of elements in the array. */ int security_get_user_sids(u32 fromsid, char *username, u32 **sids, u32 *nel) { struct context *fromcon, usercon; u32 *mysids, *mysids2, sid; u32 mynel = 0, maxnel = SIDS_NEL; struct user_datum *user; struct role_datum *role; struct av_decision avd; struct ebitmap_node *rnode, *tnode; int rc = 0, i, j; if (!ss_initialized) { *sids = NULL; *nel = 0; goto out; } POLICY_RDLOCK; fromcon = sidtab_search(&sidtab, fromsid); if (!fromcon) { rc = -EINVAL; goto out_unlock; } user = hashtab_search(policydb.p_users.table, username); if (!user) { rc = -EINVAL; goto out_unlock; } usercon.user = user->value; mysids = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC); if (!mysids) { rc = -ENOMEM; goto out_unlock; } ebitmap_for_each_bit(&user->roles, rnode, i) { if (!ebitmap_node_get_bit(rnode, i)) continue; role = policydb.role_val_to_struct[i]; usercon.role = i+1; ebitmap_for_each_bit(&role->types, tnode, j) { if (!ebitmap_node_get_bit(tnode, j)) continue; usercon.type = j+1; if (mls_setup_user_range(fromcon, user, &usercon)) continue; rc = context_struct_compute_av(fromcon, &usercon, SECCLASS_PROCESS, PROCESS__TRANSITION, &avd); if (rc || !(avd.allowed & PROCESS__TRANSITION)) continue; rc = sidtab_context_to_sid(&sidtab, &usercon, &sid); if (rc) { kfree(mysids); goto out_unlock; } if (mynel < maxnel) { mysids[mynel++] = sid; } else { maxnel += SIDS_NEL; mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC); if (!mysids2) { rc = -ENOMEM; kfree(mysids); goto out_unlock; } memcpy(mysids2, mysids, mynel * sizeof(*mysids2)); kfree(mysids); mysids = mysids2; mysids[mynel++] = sid; } } } *sids = mysids; *nel = mynel; out_unlock: POLICY_RDUNLOCK; out: return rc; } /** * security_genfs_sid - Obtain a SID for a file in a filesystem * @fstype: filesystem type * @path: path from root of mount * @sclass: file security class * @sid: SID for path * * Obtain a SID to use for a file in a filesystem that * cannot support xattr or use a fixed labeling behavior like * transition SIDs or task SIDs. */ int security_genfs_sid(const char *fstype, char *path, u16 sclass, u32 *sid) { int len; struct genfs *genfs; struct ocontext *c; int rc = 0, cmp = 0; POLICY_RDLOCK; for (genfs = policydb.genfs; genfs; genfs = genfs->next) { cmp = strcmp(fstype, genfs->fstype); if (cmp <= 0) break; } if (!genfs || cmp) { *sid = SECINITSID_UNLABELED; rc = -ENOENT; goto out; } for (c = genfs->head; c; c = c->next) { len = strlen(c->u.name); if ((!c->v.sclass || sclass == c->v.sclass) && (strncmp(c->u.name, path, len) == 0)) break; } if (!c) { *sid = SECINITSID_UNLABELED; rc = -ENOENT; goto out; } if (!c->sid[0]) { rc = sidtab_context_to_sid(&sidtab, &c->context[0], &c->sid[0]); if (rc) goto out; } *sid = c->sid[0]; out: POLICY_RDUNLOCK; return rc; } /** * security_fs_use - Determine how to handle labeling for a filesystem. * @fstype: filesystem type * @behavior: labeling behavior * @sid: SID for filesystem (superblock) */ int security_fs_use( const char *fstype, unsigned int *behavior, u32 *sid) { int rc = 0; struct ocontext *c; POLICY_RDLOCK; c = policydb.ocontexts[OCON_FSUSE]; while (c) { if (strcmp(fstype, c->u.name) == 0) break; c = c->next; } if (c) { *behavior = c->v.behavior; if (!c->sid[0]) { rc = sidtab_context_to_sid(&sidtab, &c->context[0], &c->sid[0]); if (rc) goto out; } *sid = c->sid[0]; } else { rc = security_genfs_sid(fstype, "/", SECCLASS_DIR, sid); if (rc) { *behavior = SECURITY_FS_USE_NONE; rc = 0; } else { *behavior = SECURITY_FS_USE_GENFS; } } out: POLICY_RDUNLOCK; return rc; } int security_get_bools(int *len, char ***names, int **values) { int i, rc = -ENOMEM; POLICY_RDLOCK; *names = NULL; *values = NULL; *len = policydb.p_bools.nprim; if (!*len) { rc = 0; goto out; } *names = kcalloc(*len, sizeof(char*), GFP_ATOMIC); if (!*names) goto err; *values = kcalloc(*len, sizeof(int), GFP_ATOMIC); if (!*values) goto err; for (i = 0; i < *len; i++) { size_t name_len; (*values)[i] = policydb.bool_val_to_struct[i]->state; name_len = strlen(policydb.p_bool_val_to_name[i]) + 1; (*names)[i] = kmalloc(sizeof(char) * name_len, GFP_ATOMIC); if (!(*names)[i]) goto err; strncpy((*names)[i], policydb.p_bool_val_to_name[i], name_len); (*names)[i][name_len - 1] = 0; } rc = 0; out: POLICY_RDUNLOCK; return rc; err: if (*names) { for (i = 0; i < *len; i++) kfree((*names)[i]); } kfree(*values); goto out; } int security_set_bools(int len, int *values) { int i, rc = 0; int lenp, seqno = 0; struct cond_node *cur; POLICY_WRLOCK; lenp = policydb.p_bools.nprim; if (len != lenp) { rc = -EFAULT; goto out; } for (i = 0; i < len; i++) { if (!!values[i] != policydb.bool_val_to_struct[i]->state) { audit_log(current->audit_context, GFP_ATOMIC, AUDIT_MAC_CONFIG_CHANGE, "bool=%s val=%d old_val=%d auid=%u", policydb.p_bool_val_to_name[i], !!values[i], policydb.bool_val_to_struct[i]->state, audit_get_loginuid(current->audit_context)); } if (values[i]) { policydb.bool_val_to_struct[i]->state = 1; } else { policydb.bool_val_to_struct[i]->state = 0; } } for (cur = policydb.cond_list; cur != NULL; cur = cur->next) { rc = evaluate_cond_node(&policydb, cur); if (rc) goto out; } seqno = ++latest_granting; out: POLICY_WRUNLOCK; if (!rc) { avc_ss_reset(seqno); selnl_notify_policyload(seqno); } return rc; } int security_get_bool_value(int bool) { int rc = 0; int len; POLICY_RDLOCK; len = policydb.p_bools.nprim; if (bool >= len) { rc = -EFAULT; goto out; } rc = policydb.bool_val_to_struct[bool]->state; out: POLICY_RDUNLOCK; return rc; }