diff options
Diffstat (limited to 'security/selinux/ss/services.c')
| -rw-r--r-- | security/selinux/ss/services.c | 1777 |
1 files changed, 1777 insertions, 0 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c new file mode 100644 index 00000000000..5a820cf88c9 --- /dev/null +++ b/security/selinux/ss/services.c @@ -0,0 +1,1777 @@ +/* + * Implementation of the security services. + * + * Authors : Stephen Smalley, <sds@epoch.ncsc.mil> + * James Morris <jmorris@redhat.com> + * + * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com> + * + * Support for enhanced MLS infrastructure. + * + * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com> + * + * 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 <jmorris@redhat.com> + * 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 <linux/kernel.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/spinlock.h> +#include <linux/errno.h> +#include <linux/in.h> +#include <linux/sched.h> +#include <linux/audit.h> +#include <asm/semaphore.h> +#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_datum *avdatum; + struct class_datum *tclass_datum; + + /* + * 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.source_type = scontext->type; + avkey.target_type = tcontext->type; + avkey.target_class = tclass; + avdatum = avtab_search(&policydb.te_avtab, &avkey, AVTAB_AV); + if (avdatum) { + if (avdatum->specified & AVTAB_ALLOWED) + avd->allowed = avtab_allowed(avdatum); + if (avdatum->specified & AVTAB_AUDITDENY) + avd->auditdeny = avtab_auditdeny(avdatum); + if (avdatum->specified & AVTAB_AUDITALLOW) + avd->auditallow = avtab_auditallow(avdatum); + } + + /* 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, + "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 = requested; + avd->decided = requested; + 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; + +} + +/** + * 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) +{ + 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); + 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; +} + +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, + "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; + unsigned int type_change = 0; + 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; + avdatum = avtab_search(&policydb.te_avtab, &avkey, AVTAB_TYPE); + + /* If no permanent rule, also check for enabled conditional rules */ + if(!avdatum) { + node = avtab_search_node(&policydb.te_cond_avtab, &avkey, specified); + for (; node != NULL; node = avtab_search_node_next(node, specified)) { + if (node->datum.specified & AVTAB_ENABLED) { + avdatum = &node->datum; + break; + } + } + } + + type_change = (avdatum && (avdatum->specified & specified)); + if (type_change) { + /* Use the type from the type transition/member/change rule. */ + switch (specified) { + case AVTAB_TRANSITION: + newcontext.type = avtab_transition(avdatum); + break; + case AVTAB_MEMBER: + newcontext.type = avtab_member(avdatum); + break; + case AVTAB_CHANGE: + newcontext.type = avtab_change(avdatum); + break; + } + } + + /* 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; + + LOAD_UNLOCK; + selinux_complete_init(); + 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; + 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 = kmalloc(maxnel*sizeof(*mysids), GFP_ATOMIC); + if (!mysids) { + rc = -ENOMEM; + goto out_unlock; + } + memset(mysids, 0, maxnel*sizeof(*mysids)); + + for (i = ebitmap_startbit(&user->roles); i < ebitmap_length(&user->roles); i++) { + if (!ebitmap_get_bit(&user->roles, i)) + continue; + role = policydb.role_val_to_struct[i]; + usercon.role = i+1; + for (j = ebitmap_startbit(&role->types); j < ebitmap_length(&role->types); j++) { + if (!ebitmap_get_bit(&role->types, 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 = kmalloc(maxnel*sizeof(*mysids2), GFP_ATOMIC); + if (!mysids2) { + rc = -ENOMEM; + kfree(mysids); + goto out_unlock; + } + memset(mysids2, 0, maxnel*sizeof(*mysids2)); + 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 = (char**)kmalloc(sizeof(char*) * *len, GFP_ATOMIC); + if (!*names) + goto err; + memset(*names, 0, sizeof(char*) * *len); + + *values = (int*)kmalloc(sizeof(int) * *len, 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] = (char*)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++) + if ((*names)[i]) + kfree((*names)[i]); + } + if (*values) + 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; + } + + printk(KERN_INFO "security: committed booleans { "); + for (i = 0; i < len; i++) { + if (values[i]) { + policydb.bool_val_to_struct[i]->state = 1; + } else { + policydb.bool_val_to_struct[i]->state = 0; + } + if (i != 0) + printk(", "); + printk("%s:%d", policydb.p_bool_val_to_name[i], + policydb.bool_val_to_struct[i]->state); + } + printk(" }\n"); + + 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; +} |