/* * Implementation of the kernel access vector cache (AVC). * * Authors: Stephen Smalley, * James Morris * * 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 version 2, * as published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "avc.h" #include "avc_ss.h" #ifdef CONFIG_AUDIT #include "class_to_string.h" #endif #include "common_perm_to_string.h" #include "av_inherit.h" #include "av_perm_to_string.h" #include "objsec.h" #define AVC_CACHE_SLOTS 512 #define AVC_CACHE_MAXNODES 410 struct avc_entry { u32 ssid; u32 tsid; u16 tclass; struct av_decision avd; int used; /* used recently */ }; struct avc_node { struct avc_entry ae; struct avc_node *next; }; struct avc_cache { struct avc_node *slots[AVC_CACHE_SLOTS]; u32 lru_hint; /* LRU hint for reclaim scan */ u32 active_nodes; u32 latest_notif; /* latest revocation notification */ }; struct avc_callback_node { int (*callback) (u32 event, u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 *out_retained); u32 events; u32 ssid; u32 tsid; u16 tclass; u32 perms; struct avc_callback_node *next; }; static spinlock_t avc_lock = SPIN_LOCK_UNLOCKED; static struct avc_node *avc_node_freelist = NULL; static struct avc_cache avc_cache; static unsigned avc_cache_stats[AVC_NSTATS]; static struct avc_callback_node *avc_callbacks = NULL; static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) { return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1); } /** * avc_dump_av - Display an access vector in human-readable form. * @tclass: target security class * @av: access vector */ void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) { char **common_pts = 0; u32 common_base = 0; int i, i2, perm; if (av == 0) { audit_log_format(ab, " null"); return; } for (i = 0; i < ARRAY_SIZE(av_inherit); i++) { if (av_inherit[i].tclass == tclass) { common_pts = av_inherit[i].common_pts; common_base = av_inherit[i].common_base; break; } } audit_log_format(ab, " {"); i = 0; perm = 1; while (perm < common_base) { if (perm & av) audit_log_format(ab, " %s", common_pts[i]); i++; perm <<= 1; } while (i < sizeof(av) * 8) { if (perm & av) { for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) { if ((av_perm_to_string[i2].tclass == tclass) && (av_perm_to_string[i2].value == perm)) break; } if (i2 < ARRAY_SIZE(av_perm_to_string)) audit_log_format(ab, " %s", av_perm_to_string[i2].name); } i++; perm <<= 1; } audit_log_format(ab, " }"); } /** * avc_dump_query - Display a SID pair and a class in human-readable form. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class */ void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass) { int rc; char *scontext; u32 scontext_len; rc = security_sid_to_context(ssid, &scontext, &scontext_len); if (rc) audit_log_format(ab, "ssid=%d", ssid); else { audit_log_format(ab, "scontext=%s", scontext); kfree(scontext); } rc = security_sid_to_context(tsid, &scontext, &scontext_len); if (rc) audit_log_format(ab, " tsid=%d", tsid); else { audit_log_format(ab, " tcontext=%s", scontext); kfree(scontext); } audit_log_format(ab, " tclass=%s", class_to_string[tclass]); } /** * avc_init - Initialize the AVC. * * Initialize the access vector cache. */ void __init avc_init(void) { struct avc_node *new; int i; for (i = 0; i < AVC_NSTATS; i++) avc_cache_stats[i] = 0; for (i = 0; i < AVC_CACHE_SLOTS; i++) avc_cache.slots[i] = 0; avc_cache.lru_hint = 0; avc_cache.active_nodes = 0; avc_cache.latest_notif = 0; for (i = 0; i < AVC_CACHE_MAXNODES; i++) { new = kmalloc(sizeof(*new), GFP_ATOMIC); if (!new) { printk(KERN_WARNING "avc: only able to allocate " "%d entries\n", i); break; } memset(new, 0, sizeof(*new)); new->next = avc_node_freelist; avc_node_freelist = new; } audit_log(current->audit_context, "AVC INITIALIZED\n"); } #if 0 static void avc_hash_eval(char *tag) { int i, chain_len, max_chain_len, slots_used; struct avc_node *node; unsigned long flags; spin_lock_irqsave(&avc_lock,flags); slots_used = 0; max_chain_len = 0; for (i = 0; i < AVC_CACHE_SLOTS; i++) { node = avc_cache.slots[i]; if (node) { slots_used++; chain_len = 0; while (node) { chain_len++; node = node->next; } if (chain_len > max_chain_len) max_chain_len = chain_len; } } spin_unlock_irqrestore(&avc_lock,flags); printk(KERN_INFO "\n"); printk(KERN_INFO "%s avc: %d entries and %d/%d buckets used, longest " "chain length %d\n", tag, avc_cache.active_nodes, slots_used, AVC_CACHE_SLOTS, max_chain_len); } #else static inline void avc_hash_eval(char *tag) { } #endif static inline struct avc_node *avc_reclaim_node(void) { struct avc_node *prev, *cur; int hvalue, try; hvalue = avc_cache.lru_hint; for (try = 0; try < 2; try++) { do { prev = NULL; cur = avc_cache.slots[hvalue]; while (cur) { if (!cur->ae.used) goto found; cur->ae.used = 0; prev = cur; cur = cur->next; } hvalue = (hvalue + 1) & (AVC_CACHE_SLOTS - 1); } while (hvalue != avc_cache.lru_hint); } panic("avc_reclaim_node"); found: avc_cache.lru_hint = hvalue; if (prev == NULL) avc_cache.slots[hvalue] = cur->next; else prev->next = cur->next; return cur; } static inline struct avc_node *avc_claim_node(u32 ssid, u32 tsid, u16 tclass) { struct avc_node *new; int hvalue; hvalue = avc_hash(ssid, tsid, tclass); if (avc_node_freelist) { new = avc_node_freelist; avc_node_freelist = avc_node_freelist->next; avc_cache.active_nodes++; } else { new = avc_reclaim_node(); if (!new) goto out; } new->ae.used = 1; new->ae.ssid = ssid; new->ae.tsid = tsid; new->ae.tclass = tclass; new->next = avc_cache.slots[hvalue]; avc_cache.slots[hvalue] = new; out: return new; } static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass, int *probes) { struct avc_node *cur; int hvalue; int tprobes = 1; hvalue = avc_hash(ssid, tsid, tclass); cur = avc_cache.slots[hvalue]; while (cur != NULL && (ssid != cur->ae.ssid || tclass != cur->ae.tclass || tsid != cur->ae.tsid)) { tprobes++; cur = cur->next; } if (cur == NULL) { /* cache miss */ goto out; } /* cache hit */ if (probes) *probes = tprobes; cur->ae.used = 1; out: return cur; } /** * avc_lookup - Look up an AVC entry. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions, interpreted based on @tclass * @aeref: AVC entry reference * * Look up an AVC entry that is valid for the * @requested permissions between the SID pair * (@ssid, @tsid), interpreting the permissions * based on @tclass. If a valid AVC entry exists, * then this function updates @aeref to refer to the * entry and returns %0. Otherwise, this function * returns -%ENOENT. */ int avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct avc_entry_ref *aeref) { struct avc_node *node; int probes, rc = 0; avc_cache_stats_incr(AVC_CAV_LOOKUPS); node = avc_search_node(ssid, tsid, tclass,&probes); if (node && ((node->ae.avd.decided & requested) == requested)) { avc_cache_stats_incr(AVC_CAV_HITS); avc_cache_stats_add(AVC_CAV_PROBES,probes); aeref->ae = &node->ae; goto out; } avc_cache_stats_incr(AVC_CAV_MISSES); rc = -ENOENT; out: return rc; } /** * avc_insert - Insert an AVC entry. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @ae: AVC entry * @aeref: AVC entry reference * * Insert an AVC entry for the SID pair * (@ssid, @tsid) and class @tclass. * The access vectors and the sequence number are * normally provided by the security server in * response to a security_compute_av() call. If the * sequence number @ae->avd.seqno is not less than the latest * revocation notification, then the function copies * the access vectors into a cache entry, updates * @aeref to refer to the entry, and returns %0. * Otherwise, this function returns -%EAGAIN. */ int avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae, struct avc_entry_ref *aeref) { struct avc_node *node; int rc = 0; if (ae->avd.seqno < avc_cache.latest_notif) { printk(KERN_WARNING "avc: seqno %d < latest_notif %d\n", ae->avd.seqno, avc_cache.latest_notif); rc = -EAGAIN; goto out; } node = avc_claim_node(ssid, tsid, tclass); if (!node) { rc = -ENOMEM; goto out; } node->ae.avd.allowed = ae->avd.allowed; node->ae.avd.decided = ae->avd.decided; node->ae.avd.auditallow = ae->avd.auditallow; node->ae.avd.auditdeny = ae->avd.auditdeny; node->ae.avd.seqno = ae->avd.seqno; aeref->ae = &node->ae; out: return rc; } static inline void avc_print_ipv6_addr(struct audit_buffer *ab, struct in6_addr *addr, u16 port, char *name1, char *name2) { if (!ipv6_addr_any(addr)) audit_log_format(ab, " %s=%04x:%04x:%04x:%04x:%04x:" "%04x:%04x:%04x", name1, NIP6(*addr)); if (port) audit_log_format(ab, " %s=%d", name2, ntohs(port)); } static inline void avc_print_ipv4_addr(struct audit_buffer *ab, u32 addr, u16 port, char *name1, char *name2) { if (addr) audit_log_format(ab, " %s=%d.%d.%d.%d", name1, NIPQUAD(addr)); if (port) audit_log_format(ab, " %s=%d", name2, ntohs(port)); } /** * avc_audit - Audit the granting or denial of permissions. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions * @avd: access vector decisions * @result: result from avc_has_perm_noaudit * @a: auxiliary audit data * * Audit the granting or denial of permissions in accordance * with the policy. This function is typically called by * avc_has_perm() after a permission check, but can also be * called directly by callers who use avc_has_perm_noaudit() * in order to separate the permission check from the auditing. * For example, this separation is useful when the permission check must * be performed under a lock, to allow the lock to be released * before calling the auditing code. */ void avc_audit(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct av_decision *avd, int result, struct avc_audit_data *a) { struct task_struct *tsk = current; struct inode *inode = NULL; u32 denied, audited; struct audit_buffer *ab; denied = requested & ~avd->allowed; if (denied) { audited = denied; if (!(audited & avd->auditdeny)) return; } else if (result) { audited = denied = requested; } else { audited = requested; if (!(audited & avd->auditallow)) return; } ab = audit_log_start(current->audit_context); if (!ab) return; /* audit_panic has been called */ audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted"); avc_dump_av(ab, tclass,audited); audit_log_format(ab, " for "); if (a && a->tsk) tsk = a->tsk; if (tsk && tsk->pid) { struct mm_struct *mm; struct vm_area_struct *vma; audit_log_format(ab, " pid=%d", tsk->pid); if (tsk == current) mm = current->mm; else mm = get_task_mm(tsk); if (mm) { if (down_read_trylock(&mm->mmap_sem)) { vma = mm->mmap; while (vma) { if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) { audit_log_d_path(ab, "exe=", vma->vm_file->f_dentry, vma->vm_file->f_vfsmnt); break; } vma = vma->vm_next; } up_read(&mm->mmap_sem); } if (tsk != current) mmput(mm); } else { audit_log_format(ab, " comm=%s", tsk->comm); } } if (a) { switch (a->type) { case AVC_AUDIT_DATA_IPC: audit_log_format(ab, " key=%d", a->u.ipc_id); break; case AVC_AUDIT_DATA_CAP: audit_log_format(ab, " capability=%d", a->u.cap); break; case AVC_AUDIT_DATA_FS: if (a->u.fs.dentry) { struct dentry *dentry = a->u.fs.dentry; if (a->u.fs.mnt) { audit_log_d_path(ab, "path=", dentry, a->u.fs.mnt); } else { audit_log_format(ab, " name=%s", dentry->d_name.name); } inode = dentry->d_inode; } else if (a->u.fs.inode) { struct dentry *dentry; inode = a->u.fs.inode; dentry = d_find_alias(inode); if (dentry) { audit_log_format(ab, " name=%s", dentry->d_name.name); dput(dentry); } } if (inode) audit_log_format(ab, " dev=%s ino=%ld", inode->i_sb->s_id, inode->i_ino); break; case AVC_AUDIT_DATA_NET: if (a->u.net.sk) { struct sock *sk = a->u.net.sk; struct unix_sock *u; int len = 0; char *p = NULL; switch (sk->sk_family) { case AF_INET: { struct inet_opt *inet = inet_sk(sk); avc_print_ipv4_addr(ab, inet->rcv_saddr, inet->sport, "laddr", "lport"); avc_print_ipv4_addr(ab, inet->daddr, inet->dport, "faddr", "fport"); break; } case AF_INET6: { struct inet_opt *inet = inet_sk(sk); struct ipv6_pinfo *inet6 = inet6_sk(sk); avc_print_ipv6_addr(ab, &inet6->rcv_saddr, inet->sport, "laddr", "lport"); avc_print_ipv6_addr(ab, &inet6->daddr, inet->dport, "faddr", "fport"); break; } case AF_UNIX: u = unix_sk(sk); if (u->dentry) { audit_log_d_path(ab, "path=", u->dentry, u->mnt); break; } if (!u->addr) break; len = u->addr->len-sizeof(short); p = &u->addr->name->sun_path[0]; if (*p) audit_log_format(ab, "path=%*.*s", len, len, p); else audit_log_format(ab, "path=@%*.*s", len-1, len-1, p+1); break; } } switch (a->u.net.family) { case AF_INET: avc_print_ipv4_addr(ab, a->u.net.v4info.saddr, a->u.net.sport, "saddr", "src"); avc_print_ipv4_addr(ab, a->u.net.v4info.daddr, a->u.net.dport, "daddr", "dest"); break; case AF_INET6: avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr, a->u.net.sport, "saddr", "src"); avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr, a->u.net.dport, "daddr", "dest"); break; } if (a->u.net.netif) audit_log_format(ab, " netif=%s", a->u.net.netif); break; } } audit_log_format(ab, " "); avc_dump_query(ab, ssid, tsid, tclass); audit_log_end(ab); } /** * avc_add_callback - Register a callback for security events. * @callback: callback function * @events: security events * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions * * Register a callback function for events in the set @events * related to the SID pair (@ssid, @tsid) and * and the permissions @perms, interpreting * @perms based on @tclass. Returns %0 on success or * -%ENOMEM if insufficient memory exists to add the callback. */ int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 *out_retained), u32 events, u32 ssid, u32 tsid, u16 tclass, u32 perms) { struct avc_callback_node *c; int rc = 0; c = kmalloc(sizeof(*c), GFP_ATOMIC); if (!c) { rc = -ENOMEM; goto out; } c->callback = callback; c->events = events; c->ssid = ssid; c->tsid = tsid; c->perms = perms; c->next = avc_callbacks; avc_callbacks = c; out: return rc; } static inline int avc_sidcmp(u32 x, u32 y) { return (x == y || x == SECSID_WILD || y == SECSID_WILD); } static inline void avc_update_node(u32 event, struct avc_node *node, u32 perms) { switch (event) { case AVC_CALLBACK_GRANT: node->ae.avd.allowed |= perms; break; case AVC_CALLBACK_TRY_REVOKE: case AVC_CALLBACK_REVOKE: node->ae.avd.allowed &= ~perms; break; case AVC_CALLBACK_AUDITALLOW_ENABLE: node->ae.avd.auditallow |= perms; break; case AVC_CALLBACK_AUDITALLOW_DISABLE: node->ae.avd.auditallow &= ~perms; break; case AVC_CALLBACK_AUDITDENY_ENABLE: node->ae.avd.auditdeny |= perms; break; case AVC_CALLBACK_AUDITDENY_DISABLE: node->ae.avd.auditdeny &= ~perms; break; } } static int avc_update_cache(u32 event, u32 ssid, u32 tsid, u16 tclass, u32 perms) { struct avc_node *node; int i; unsigned long flags; spin_lock_irqsave(&avc_lock,flags); if (ssid == SECSID_WILD || tsid == SECSID_WILD) { /* apply to all matching nodes */ for (i = 0; i < AVC_CACHE_SLOTS; i++) { for (node = avc_cache.slots[i]; node; node = node->next) { if (avc_sidcmp(ssid, node->ae.ssid) && avc_sidcmp(tsid, node->ae.tsid) && tclass == node->ae.tclass) { avc_update_node(event,node,perms); } } } } else { /* apply to one node */ node = avc_search_node(ssid, tsid, tclass, 0); if (node) { avc_update_node(event,node,perms); } } spin_unlock_irqrestore(&avc_lock,flags); return 0; } static int avc_control(u32 event, u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno, u32 *out_retained) { struct avc_callback_node *c; u32 tretained = 0, cretained = 0; int rc = 0; unsigned long flags; /* * try_revoke only removes permissions from the cache * state if they are not retained by the object manager. * Hence, try_revoke must wait until after the callbacks have * been invoked to update the cache state. */ if (event != AVC_CALLBACK_TRY_REVOKE) avc_update_cache(event,ssid,tsid,tclass,perms); for (c = avc_callbacks; c; c = c->next) { if ((c->events & event) && avc_sidcmp(c->ssid, ssid) && avc_sidcmp(c->tsid, tsid) && c->tclass == tclass && (c->perms & perms)) { cretained = 0; rc = c->callback(event, ssid, tsid, tclass, (c->perms & perms), &cretained); if (rc) goto out; tretained |= cretained; } } if (event == AVC_CALLBACK_TRY_REVOKE) { /* revoke any unretained permissions */ perms &= ~tretained; avc_update_cache(event,ssid,tsid,tclass,perms); *out_retained = tretained; } spin_lock_irqsave(&avc_lock,flags); if (seqno > avc_cache.latest_notif) avc_cache.latest_notif = seqno; spin_unlock_irqrestore(&avc_lock,flags); out: return rc; } /** * avc_ss_grant - Grant previously denied permissions. * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions to grant * @seqno: policy sequence number */ int avc_ss_grant(u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno) { return avc_control(AVC_CALLBACK_GRANT, ssid, tsid, tclass, perms, seqno, 0); } /** * avc_ss_try_revoke - Try to revoke previously granted permissions. * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions to grant * @seqno: policy sequence number * @out_retained: subset of @perms that are retained * * Try to revoke previously granted permissions, but * only if they are not retained as migrated permissions. * Return the subset of permissions that are retained via @out_retained. */ int avc_ss_try_revoke(u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno, u32 *out_retained) { return avc_control(AVC_CALLBACK_TRY_REVOKE, ssid, tsid, tclass, perms, seqno, out_retained); } /** * avc_ss_revoke - Revoke previously granted permissions. * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions to grant * @seqno: policy sequence number * * Revoke previously granted permissions, even if * they are retained as migrated permissions. */ int avc_ss_revoke(u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno) { return avc_control(AVC_CALLBACK_REVOKE, ssid, tsid, tclass, perms, seqno, 0); } /** * avc_ss_reset - Flush the cache and revalidate migrated permissions. * @seqno: policy sequence number */ int avc_ss_reset(u32 seqno) { struct avc_callback_node *c; int i, rc = 0; struct avc_node *node, *tmp; unsigned long flags; avc_hash_eval("reset"); spin_lock_irqsave(&avc_lock,flags); for (i = 0; i < AVC_CACHE_SLOTS; i++) { node = avc_cache.slots[i]; while (node) { tmp = node; node = node->next; tmp->ae.ssid = tmp->ae.tsid = SECSID_NULL; tmp->ae.tclass = SECCLASS_NULL; tmp->ae.avd.allowed = tmp->ae.avd.decided = 0; tmp->ae.avd.auditallow = tmp->ae.avd.auditdeny = 0; tmp->ae.used = 0; tmp->next = avc_node_freelist; avc_node_freelist = tmp; avc_cache.active_nodes--; } avc_cache.slots[i] = 0; } avc_cache.lru_hint = 0; spin_unlock_irqrestore(&avc_lock,flags); for (i = 0; i < AVC_NSTATS; i++) avc_cache_stats[i] = 0; for (c = avc_callbacks; c; c = c->next) { if (c->events & AVC_CALLBACK_RESET) { rc = c->callback(AVC_CALLBACK_RESET, 0, 0, 0, 0, 0); if (rc) goto out; } } spin_lock_irqsave(&avc_lock,flags); if (seqno > avc_cache.latest_notif) avc_cache.latest_notif = seqno; spin_unlock_irqrestore(&avc_lock,flags); out: return rc; } /** * avc_ss_set_auditallow - Enable or disable auditing of granted permissions. * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions to grant * @seqno: policy sequence number * @enable: enable flag. */ int avc_ss_set_auditallow(u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno, u32 enable) { if (enable) return avc_control(AVC_CALLBACK_AUDITALLOW_ENABLE, ssid, tsid, tclass, perms, seqno, 0); else return avc_control(AVC_CALLBACK_AUDITALLOW_DISABLE, ssid, tsid, tclass, perms, seqno, 0); } /** * avc_ss_set_auditdeny - Enable or disable auditing of denied permissions. * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions to grant * @seqno: policy sequence number * @enable: enable flag. */ int avc_ss_set_auditdeny(u32 ssid, u32 tsid, u16 tclass, u32 perms, u32 seqno, u32 enable) { if (enable) return avc_control(AVC_CALLBACK_AUDITDENY_ENABLE, ssid, tsid, tclass, perms, seqno, 0); else return avc_control(AVC_CALLBACK_AUDITDENY_DISABLE, ssid, tsid, tclass, perms, seqno, 0); } /** * avc_has_perm_noaudit - Check permissions but perform no auditing. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions, interpreted based on @tclass * @aeref: AVC entry reference * @avd: access vector decisions * * Check the AVC to determine whether the @requested permissions are granted * for the SID pair (@ssid, @tsid), interpreting the permissions * based on @tclass, and call the security server on a cache miss to obtain * a new decision and add it to the cache. Update @aeref to refer to an AVC * entry with the resulting decisions, and return a copy of the decisions * in @avd. Return %0 if all @requested permissions are granted, * -%EACCES if any permissions are denied, or another -errno upon * other errors. This function is typically called by avc_has_perm(), * but may also be called directly to separate permission checking from * auditing, e.g. in cases where a lock must be held for the check but * should be released for the auditing. */ int avc_has_perm_noaudit(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct avc_entry_ref *aeref, struct av_decision *avd) { struct avc_entry *ae; int rc = 0; unsigned long flags; struct avc_entry entry; u32 denied; struct avc_entry_ref ref; if (!aeref) { avc_entry_ref_init(&ref); aeref = &ref; } spin_lock_irqsave(&avc_lock, flags); avc_cache_stats_incr(AVC_ENTRY_LOOKUPS); ae = aeref->ae; if (ae) { if (ae->ssid == ssid && ae->tsid == tsid && ae->tclass == tclass && ((ae->avd.decided & requested) == requested)) { avc_cache_stats_incr(AVC_ENTRY_HITS); ae->used = 1; } else { avc_cache_stats_incr(AVC_ENTRY_DISCARDS); ae = 0; } } if (!ae) { avc_cache_stats_incr(AVC_ENTRY_MISSES); rc = avc_lookup(ssid, tsid, tclass, requested, aeref); if (rc) { spin_unlock_irqrestore(&avc_lock,flags); rc = security_compute_av(ssid,tsid,tclass,requested,&entry.avd); if (rc) goto out; spin_lock_irqsave(&avc_lock, flags); rc = avc_insert(ssid,tsid,tclass,&entry,aeref); if (rc) { spin_unlock_irqrestore(&avc_lock,flags); goto out; } } ae = aeref->ae; } if (avd) memcpy(avd, &ae->avd, sizeof(*avd)); denied = requested & ~(ae->avd.allowed); if (!requested || denied) { if (selinux_enforcing) { spin_unlock_irqrestore(&avc_lock,flags); rc = -EACCES; goto out; } else { ae->avd.allowed |= requested; spin_unlock_irqrestore(&avc_lock,flags); goto out; } } spin_unlock_irqrestore(&avc_lock,flags); out: return rc; } /** * avc_has_perm - Check permissions and perform any appropriate auditing. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions, interpreted based on @tclass * @aeref: AVC entry reference * @auditdata: auxiliary audit data * * Check the AVC to determine whether the @requested permissions are granted * for the SID pair (@ssid, @tsid), interpreting the permissions * based on @tclass, and call the security server on a cache miss to obtain * a new decision and add it to the cache. Update @aeref to refer to an AVC * entry with the resulting decisions. Audit the granting or denial of * permissions in accordance with the policy. Return %0 if all @requested * permissions are granted, -%EACCES if any permissions are denied, or * another -errno upon other errors. */ int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct avc_entry_ref *aeref, struct avc_audit_data *auditdata) { struct av_decision avd; int rc; rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, aeref, &avd); avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata); return rc; }