From 671a2781ff01abf4fdc8904881fc3abd3a8279af Mon Sep 17 00:00:00 2001 From: Jeff Vander Stoep Date: Fri, 10 Jul 2015 17:19:55 -0400 Subject: [PATCH 1/7] security: add ioctl specific auditing to lsm_audit Add information about ioctl calls to the LSM audit data. Log the file path and command number. Signed-off-by: Jeff Vander Stoep Acked-by: Nick Kralevich [PM: subject line tweak] Signed-off-by: Paul Moore --- include/linux/lsm_audit.h | 7 +++++++ security/lsm_audit.c | 15 +++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h index 1cc89e9df480..ffb9c9da4f39 100644 --- a/include/linux/lsm_audit.h +++ b/include/linux/lsm_audit.h @@ -40,6 +40,11 @@ struct lsm_network_audit { } fam; }; +struct lsm_ioctlop_audit { + struct path path; + u16 cmd; +}; + /* Auxiliary data to use in generating the audit record. */ struct common_audit_data { char type; @@ -53,6 +58,7 @@ struct common_audit_data { #define LSM_AUDIT_DATA_KMOD 8 #define LSM_AUDIT_DATA_INODE 9 #define LSM_AUDIT_DATA_DENTRY 10 +#define LSM_AUDIT_DATA_IOCTL_OP 11 union { struct path path; struct dentry *dentry; @@ -68,6 +74,7 @@ struct common_audit_data { } key_struct; #endif char *kmod_name; + struct lsm_ioctlop_audit *op; } u; /* this union contains LSM specific data */ union { diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 1d34277dc402..9f6c649c65e9 100644 --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -245,6 +245,21 @@ static void dump_common_audit_data(struct audit_buffer *ab, } break; } + case LSM_AUDIT_DATA_IOCTL_OP: { + struct inode *inode; + + audit_log_d_path(ab, " path=", &a->u.op->path); + + inode = a->u.op->path.dentry->d_inode; + if (inode) { + audit_log_format(ab, " dev="); + audit_log_untrustedstring(ab, inode->i_sb->s_id); + audit_log_format(ab, " ino=%lu", inode->i_ino); + } + + audit_log_format(ab, " ioctlcmd=%hx", a->u.op->cmd); + break; + } case LSM_AUDIT_DATA_DENTRY: { struct inode *inode; From fa1aa143ac4a682c7f5fd52a3cf05f5a6fe44a0a Mon Sep 17 00:00:00 2001 From: Jeff Vander Stoep Date: Fri, 10 Jul 2015 17:19:56 -0400 Subject: [PATCH 2/7] selinux: extended permissions for ioctls Add extended permissions logic to selinux. Extended permissions provides additional permissions in 256 bit increments. Extend the generic ioctl permission check to use the extended permissions for per-command filtering. Source/target/class sets including the ioctl permission may additionally include a set of commands. Example: allowxperm : ioctl unpriv_app_socket_cmds auditallowxperm : ioctl priv_gpu_cmds Where unpriv_app_socket_cmds and priv_gpu_cmds are macros representing commonly granted sets of ioctl commands. When ioctl commands are omitted only the permissions are checked. This feature is intended to provide finer granularity for the ioctl permission that may be too imprecise. For example, the same driver may use ioctls to provide important and benign functionality such as driver version or socket type as well as dangerous capabilities such as debugging features, read/write/execute to physical memory or access to sensitive data. Per-command filtering provides a mechanism to reduce the attack surface of the kernel, and limit applications to the subset of commands required. The format of the policy binary has been modified to include ioctl commands, and the policy version number has been incremented to POLICYDB_VERSION_XPERMS_IOCTL=30 to account for the format change. The extended permissions logic is deliberately generic to allow components to be reused e.g. netlink filters Signed-off-by: Jeff Vander Stoep Acked-by: Nick Kralevich Signed-off-by: Paul Moore --- security/selinux/avc.c | 415 +++++++++++++++++++++++++++- security/selinux/hooks.c | 42 ++- security/selinux/include/avc.h | 6 + security/selinux/include/security.h | 32 ++- security/selinux/ss/avtab.c | 104 ++++++- security/selinux/ss/avtab.h | 33 ++- security/selinux/ss/conditional.c | 38 ++- security/selinux/ss/conditional.h | 6 +- security/selinux/ss/policydb.c | 5 + security/selinux/ss/services.c | 213 ++++++++++++-- security/selinux/ss/services.h | 6 + 11 files changed, 837 insertions(+), 63 deletions(-) diff --git a/security/selinux/avc.c b/security/selinux/avc.c index 3c17dda9571d..2d5e1b04cd50 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -48,6 +49,7 @@ struct avc_entry { u32 tsid; u16 tclass; struct av_decision avd; + struct avc_xperms_node *xp_node; }; struct avc_node { @@ -56,6 +58,16 @@ struct avc_node { struct rcu_head rhead; }; +struct avc_xperms_decision_node { + struct extended_perms_decision xpd; + struct list_head xpd_list; /* list of extended_perms_decision */ +}; + +struct avc_xperms_node { + struct extended_perms xp; + struct list_head xpd_head; /* list head of extended_perms_decision */ +}; + struct avc_cache { struct hlist_head slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */ spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */ @@ -80,6 +92,9 @@ DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 }; static struct avc_cache avc_cache; static struct avc_callback_node *avc_callbacks; static struct kmem_cache *avc_node_cachep; +static struct kmem_cache *avc_xperms_data_cachep; +static struct kmem_cache *avc_xperms_decision_cachep; +static struct kmem_cache *avc_xperms_cachep; static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) { @@ -170,7 +185,17 @@ void __init avc_init(void) atomic_set(&avc_cache.lru_hint, 0); avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node), - 0, SLAB_PANIC, NULL); + 0, SLAB_PANIC, NULL); + avc_xperms_cachep = kmem_cache_create("avc_xperms_node", + sizeof(struct avc_xperms_node), + 0, SLAB_PANIC, NULL); + avc_xperms_decision_cachep = kmem_cache_create( + "avc_xperms_decision_node", + sizeof(struct avc_xperms_decision_node), + 0, SLAB_PANIC, NULL); + avc_xperms_data_cachep = kmem_cache_create("avc_xperms_data", + sizeof(struct extended_perms_data), + 0, SLAB_PANIC, NULL); audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n"); } @@ -205,9 +230,261 @@ int avc_get_hash_stats(char *page) slots_used, AVC_CACHE_SLOTS, max_chain_len); } +/* + * using a linked list for extended_perms_decision lookup because the list is + * always small. i.e. less than 5, typically 1 + */ +static struct extended_perms_decision *avc_xperms_decision_lookup(u8 driver, + struct avc_xperms_node *xp_node) +{ + struct avc_xperms_decision_node *xpd_node; + + list_for_each_entry(xpd_node, &xp_node->xpd_head, xpd_list) { + if (xpd_node->xpd.driver == driver) + return &xpd_node->xpd; + } + return NULL; +} + +static inline unsigned int +avc_xperms_has_perm(struct extended_perms_decision *xpd, + u8 perm, u8 which) +{ + unsigned int rc = 0; + + if ((which == XPERMS_ALLOWED) && + (xpd->used & XPERMS_ALLOWED)) + rc = security_xperm_test(xpd->allowed->p, perm); + else if ((which == XPERMS_AUDITALLOW) && + (xpd->used & XPERMS_AUDITALLOW)) + rc = security_xperm_test(xpd->auditallow->p, perm); + else if ((which == XPERMS_DONTAUDIT) && + (xpd->used & XPERMS_DONTAUDIT)) + rc = security_xperm_test(xpd->dontaudit->p, perm); + return rc; +} + +static void avc_xperms_allow_perm(struct avc_xperms_node *xp_node, + u8 driver, u8 perm) +{ + struct extended_perms_decision *xpd; + security_xperm_set(xp_node->xp.drivers.p, driver); + xpd = avc_xperms_decision_lookup(driver, xp_node); + if (xpd && xpd->allowed) + security_xperm_set(xpd->allowed->p, perm); +} + +static void avc_xperms_decision_free(struct avc_xperms_decision_node *xpd_node) +{ + struct extended_perms_decision *xpd; + + xpd = &xpd_node->xpd; + if (xpd->allowed) + kmem_cache_free(avc_xperms_data_cachep, xpd->allowed); + if (xpd->auditallow) + kmem_cache_free(avc_xperms_data_cachep, xpd->auditallow); + if (xpd->dontaudit) + kmem_cache_free(avc_xperms_data_cachep, xpd->dontaudit); + kmem_cache_free(avc_xperms_decision_cachep, xpd_node); +} + +static void avc_xperms_free(struct avc_xperms_node *xp_node) +{ + struct avc_xperms_decision_node *xpd_node, *tmp; + + if (!xp_node) + return; + + list_for_each_entry_safe(xpd_node, tmp, &xp_node->xpd_head, xpd_list) { + list_del(&xpd_node->xpd_list); + avc_xperms_decision_free(xpd_node); + } + kmem_cache_free(avc_xperms_cachep, xp_node); +} + +static void avc_copy_xperms_decision(struct extended_perms_decision *dest, + struct extended_perms_decision *src) +{ + dest->driver = src->driver; + dest->used = src->used; + if (dest->used & XPERMS_ALLOWED) + memcpy(dest->allowed->p, src->allowed->p, + sizeof(src->allowed->p)); + if (dest->used & XPERMS_AUDITALLOW) + memcpy(dest->auditallow->p, src->auditallow->p, + sizeof(src->auditallow->p)); + if (dest->used & XPERMS_DONTAUDIT) + memcpy(dest->dontaudit->p, src->dontaudit->p, + sizeof(src->dontaudit->p)); +} + +/* + * similar to avc_copy_xperms_decision, but only copy decision + * information relevant to this perm + */ +static inline void avc_quick_copy_xperms_decision(u8 perm, + struct extended_perms_decision *dest, + struct extended_perms_decision *src) +{ + /* + * compute index of the u32 of the 256 bits (8 u32s) that contain this + * command permission + */ + u8 i = perm >> 5; + + dest->used = src->used; + if (dest->used & XPERMS_ALLOWED) + dest->allowed->p[i] = src->allowed->p[i]; + if (dest->used & XPERMS_AUDITALLOW) + dest->auditallow->p[i] = src->auditallow->p[i]; + if (dest->used & XPERMS_DONTAUDIT) + dest->dontaudit->p[i] = src->dontaudit->p[i]; +} + +static struct avc_xperms_decision_node + *avc_xperms_decision_alloc(u8 which) +{ + struct avc_xperms_decision_node *xpd_node; + struct extended_perms_decision *xpd; + + xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, + GFP_ATOMIC | __GFP_NOMEMALLOC); + if (!xpd_node) + return NULL; + + xpd = &xpd_node->xpd; + if (which & XPERMS_ALLOWED) { + xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep, + GFP_ATOMIC | __GFP_NOMEMALLOC); + if (!xpd->allowed) + goto error; + } + if (which & XPERMS_AUDITALLOW) { + xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep, + GFP_ATOMIC | __GFP_NOMEMALLOC); + if (!xpd->auditallow) + goto error; + } + if (which & XPERMS_DONTAUDIT) { + xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep, + GFP_ATOMIC | __GFP_NOMEMALLOC); + if (!xpd->dontaudit) + goto error; + } + return xpd_node; +error: + avc_xperms_decision_free(xpd_node); + return NULL; +} + +static int avc_add_xperms_decision(struct avc_node *node, + struct extended_perms_decision *src) +{ + struct avc_xperms_decision_node *dest_xpd; + + node->ae.xp_node->xp.len++; + dest_xpd = avc_xperms_decision_alloc(src->used); + if (!dest_xpd) + return -ENOMEM; + avc_copy_xperms_decision(&dest_xpd->xpd, src); + list_add(&dest_xpd->xpd_list, &node->ae.xp_node->xpd_head); + return 0; +} + +static struct avc_xperms_node *avc_xperms_alloc(void) +{ + struct avc_xperms_node *xp_node; + + xp_node = kmem_cache_zalloc(avc_xperms_cachep, + GFP_ATOMIC|__GFP_NOMEMALLOC); + if (!xp_node) + return xp_node; + INIT_LIST_HEAD(&xp_node->xpd_head); + return xp_node; +} + +static int avc_xperms_populate(struct avc_node *node, + struct avc_xperms_node *src) +{ + struct avc_xperms_node *dest; + struct avc_xperms_decision_node *dest_xpd; + struct avc_xperms_decision_node *src_xpd; + + if (src->xp.len == 0) + return 0; + dest = avc_xperms_alloc(); + if (!dest) + return -ENOMEM; + + memcpy(dest->xp.drivers.p, src->xp.drivers.p, sizeof(dest->xp.drivers.p)); + dest->xp.len = src->xp.len; + + /* for each source xpd allocate a destination xpd and copy */ + list_for_each_entry(src_xpd, &src->xpd_head, xpd_list) { + dest_xpd = avc_xperms_decision_alloc(src_xpd->xpd.used); + if (!dest_xpd) + goto error; + avc_copy_xperms_decision(&dest_xpd->xpd, &src_xpd->xpd); + list_add(&dest_xpd->xpd_list, &dest->xpd_head); + } + node->ae.xp_node = dest; + return 0; +error: + avc_xperms_free(dest); + return -ENOMEM; + +} + +static inline u32 avc_xperms_audit_required(u32 requested, + struct av_decision *avd, + struct extended_perms_decision *xpd, + u8 perm, + int result, + u32 *deniedp) +{ + u32 denied, audited; + + denied = requested & ~avd->allowed; + if (unlikely(denied)) { + audited = denied & avd->auditdeny; + if (audited && xpd) { + if (avc_xperms_has_perm(xpd, perm, XPERMS_DONTAUDIT)) + audited &= ~requested; + } + } else if (result) { + audited = denied = requested; + } else { + audited = requested & avd->auditallow; + if (audited && xpd) { + if (!avc_xperms_has_perm(xpd, perm, XPERMS_AUDITALLOW)) + audited &= ~requested; + } + } + + *deniedp = denied; + return audited; +} + +static inline int avc_xperms_audit(u32 ssid, u32 tsid, u16 tclass, + u32 requested, struct av_decision *avd, + struct extended_perms_decision *xpd, + u8 perm, int result, + struct common_audit_data *ad) +{ + u32 audited, denied; + + audited = avc_xperms_audit_required( + requested, avd, xpd, perm, result, &denied); + if (likely(!audited)) + return 0; + return slow_avc_audit(ssid, tsid, tclass, requested, + audited, denied, result, ad, 0); +} + static void avc_node_free(struct rcu_head *rhead) { struct avc_node *node = container_of(rhead, struct avc_node, rhead); + avc_xperms_free(node->ae.xp_node); kmem_cache_free(avc_node_cachep, node); avc_cache_stats_incr(frees); } @@ -221,6 +498,7 @@ static void avc_node_delete(struct avc_node *node) static void avc_node_kill(struct avc_node *node) { + avc_xperms_free(node->ae.xp_node); kmem_cache_free(avc_node_cachep, node); avc_cache_stats_incr(frees); atomic_dec(&avc_cache.active_nodes); @@ -367,6 +645,7 @@ static int avc_latest_notif_update(int seqno, int is_insert) * @tsid: target security identifier * @tclass: target security class * @avd: resulting av decision + * @xp_node: resulting extended permissions * * Insert an AVC entry for the SID pair * (@ssid, @tsid) and class @tclass. @@ -378,7 +657,9 @@ static int avc_latest_notif_update(int seqno, int is_insert) * the access vectors into a cache entry, returns * avc_node inserted. Otherwise, this function returns NULL. */ -static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd) +static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, + struct av_decision *avd, + struct avc_xperms_node *xp_node) { struct avc_node *pos, *node = NULL; int hvalue; @@ -391,10 +672,15 @@ static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_dec if (node) { struct hlist_head *head; spinlock_t *lock; + int rc = 0; hvalue = avc_hash(ssid, tsid, tclass); avc_node_populate(node, ssid, tsid, tclass, avd); - + rc = avc_xperms_populate(node, xp_node); + if (rc) { + kmem_cache_free(avc_node_cachep, node); + return NULL; + } head = &avc_cache.slots[hvalue]; lock = &avc_cache.slots_lock[hvalue]; @@ -523,14 +809,17 @@ int __init avc_add_callback(int (*callback)(u32 event), u32 events) * @perms : Permission mask bits * @ssid,@tsid,@tclass : identifier of an AVC entry * @seqno : sequence number when decision was made + * @xpd: extended_perms_decision to be added to the node * * if a valid AVC entry doesn't exist,this function returns -ENOENT. * if kmalloc() called internal returns NULL, this function returns -ENOMEM. * otherwise, this function updates the AVC entry. The original AVC-entry object * will release later by RCU. */ -static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, - u32 seqno) +static int avc_update_node(u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid, + u32 tsid, u16 tclass, u32 seqno, + struct extended_perms_decision *xpd, + u32 flags) { int hvalue, rc = 0; unsigned long flag; @@ -574,9 +863,19 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd); + if (orig->ae.xp_node) { + rc = avc_xperms_populate(node, orig->ae.xp_node); + if (rc) { + kmem_cache_free(avc_node_cachep, node); + goto out_unlock; + } + } + switch (event) { case AVC_CALLBACK_GRANT: node->ae.avd.allowed |= perms; + if (node->ae.xp_node && (flags & AVC_EXTENDED_PERMS)) + avc_xperms_allow_perm(node->ae.xp_node, driver, xperm); break; case AVC_CALLBACK_TRY_REVOKE: case AVC_CALLBACK_REVOKE: @@ -594,6 +893,9 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, case AVC_CALLBACK_AUDITDENY_DISABLE: node->ae.avd.auditdeny &= ~perms; break; + case AVC_CALLBACK_ADD_XPERMS: + avc_add_xperms_decision(node, xpd); + break; } avc_node_replace(node, orig); out_unlock: @@ -665,18 +967,20 @@ int avc_ss_reset(u32 seqno) * results in a bigger stack frame. */ static noinline struct avc_node *avc_compute_av(u32 ssid, u32 tsid, - u16 tclass, struct av_decision *avd) + u16 tclass, struct av_decision *avd, + struct avc_xperms_node *xp_node) { rcu_read_unlock(); - security_compute_av(ssid, tsid, tclass, avd); + INIT_LIST_HEAD(&xp_node->xpd_head); + security_compute_av(ssid, tsid, tclass, avd, &xp_node->xp); rcu_read_lock(); - return avc_insert(ssid, tsid, tclass, avd); + return avc_insert(ssid, tsid, tclass, avd, xp_node); } static noinline int avc_denied(u32 ssid, u32 tsid, - u16 tclass, u32 requested, - unsigned flags, - struct av_decision *avd) + u16 tclass, u32 requested, + u8 driver, u8 xperm, unsigned flags, + struct av_decision *avd) { if (flags & AVC_STRICT) return -EACCES; @@ -684,11 +988,91 @@ static noinline int avc_denied(u32 ssid, u32 tsid, if (selinux_enforcing && !(avd->flags & AVD_FLAGS_PERMISSIVE)) return -EACCES; - avc_update_node(AVC_CALLBACK_GRANT, requested, ssid, - tsid, tclass, avd->seqno); + avc_update_node(AVC_CALLBACK_GRANT, requested, driver, xperm, ssid, + tsid, tclass, avd->seqno, NULL, flags); return 0; } +/* + * The avc extended permissions logic adds an additional 256 bits of + * permissions to an avc node when extended permissions for that node are + * specified in the avtab. If the additional 256 permissions is not adequate, + * as-is the case with ioctls, then multiple may be chained together and the + * driver field is used to specify which set contains the permission. + */ +int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested, + u8 driver, u8 xperm, struct common_audit_data *ad) +{ + struct avc_node *node; + struct av_decision avd; + u32 denied; + struct extended_perms_decision local_xpd; + struct extended_perms_decision *xpd = NULL; + struct extended_perms_data allowed; + struct extended_perms_data auditallow; + struct extended_perms_data dontaudit; + struct avc_xperms_node local_xp_node; + struct avc_xperms_node *xp_node; + int rc = 0, rc2; + + xp_node = &local_xp_node; + BUG_ON(!requested); + + rcu_read_lock(); + + node = avc_lookup(ssid, tsid, tclass); + if (unlikely(!node)) { + node = avc_compute_av(ssid, tsid, tclass, &avd, xp_node); + } else { + memcpy(&avd, &node->ae.avd, sizeof(avd)); + xp_node = node->ae.xp_node; + } + /* if extended permissions are not defined, only consider av_decision */ + if (!xp_node || !xp_node->xp.len) + goto decision; + + local_xpd.allowed = &allowed; + local_xpd.auditallow = &auditallow; + local_xpd.dontaudit = &dontaudit; + + xpd = avc_xperms_decision_lookup(driver, xp_node); + if (unlikely(!xpd)) { + /* + * Compute the extended_perms_decision only if the driver + * is flagged + */ + if (!security_xperm_test(xp_node->xp.drivers.p, driver)) { + avd.allowed &= ~requested; + goto decision; + } + rcu_read_unlock(); + security_compute_xperms_decision(ssid, tsid, tclass, driver, + &local_xpd); + rcu_read_lock(); + avc_update_node(AVC_CALLBACK_ADD_XPERMS, requested, driver, xperm, + ssid, tsid, tclass, avd.seqno, &local_xpd, 0); + } else { + avc_quick_copy_xperms_decision(xperm, &local_xpd, xpd); + } + xpd = &local_xpd; + + if (!avc_xperms_has_perm(xpd, xperm, XPERMS_ALLOWED)) + avd.allowed &= ~requested; + +decision: + denied = requested & ~(avd.allowed); + if (unlikely(denied)) + rc = avc_denied(ssid, tsid, tclass, requested, driver, xperm, + AVC_EXTENDED_PERMS, &avd); + + rcu_read_unlock(); + + rc2 = avc_xperms_audit(ssid, tsid, tclass, requested, + &avd, xpd, xperm, rc, ad); + if (rc2) + return rc2; + return rc; +} /** * avc_has_perm_noaudit - Check permissions but perform no auditing. @@ -716,6 +1100,7 @@ inline int avc_has_perm_noaudit(u32 ssid, u32 tsid, struct av_decision *avd) { struct avc_node *node; + struct avc_xperms_node xp_node; int rc = 0; u32 denied; @@ -725,13 +1110,13 @@ inline int avc_has_perm_noaudit(u32 ssid, u32 tsid, node = avc_lookup(ssid, tsid, tclass); if (unlikely(!node)) - node = avc_compute_av(ssid, tsid, tclass, avd); + node = avc_compute_av(ssid, tsid, tclass, avd, &xp_node); else memcpy(avd, &node->ae.avd, sizeof(*avd)); denied = requested & ~(avd->allowed); if (unlikely(denied)) - rc = avc_denied(ssid, tsid, tclass, requested, flags, avd); + rc = avc_denied(ssid, tsid, tclass, requested, 0, 0, flags, avd); rcu_read_unlock(); return rc; diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 692e3cc8ce23..a049b7216270 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3216,6 +3216,46 @@ static void selinux_file_free_security(struct file *file) file_free_security(file); } +/* + * Check whether a task has the ioctl permission and cmd + * operation to an inode. + */ +int ioctl_has_perm(const struct cred *cred, struct file *file, + u32 requested, u16 cmd) +{ + struct common_audit_data ad; + struct file_security_struct *fsec = file->f_security; + struct inode *inode = file_inode(file); + struct inode_security_struct *isec = inode->i_security; + struct lsm_ioctlop_audit ioctl; + u32 ssid = cred_sid(cred); + int rc; + u8 driver = cmd >> 8; + u8 xperm = cmd & 0xff; + + ad.type = LSM_AUDIT_DATA_IOCTL_OP; + ad.u.op = &ioctl; + ad.u.op->cmd = cmd; + ad.u.op->path = file->f_path; + + if (ssid != fsec->sid) { + rc = avc_has_perm(ssid, fsec->sid, + SECCLASS_FD, + FD__USE, + &ad); + if (rc) + goto out; + } + + if (unlikely(IS_PRIVATE(inode))) + return 0; + + rc = avc_has_extended_perms(ssid, isec->sid, isec->sclass, + requested, driver, xperm, &ad); +out: + return rc; +} + static int selinux_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -3258,7 +3298,7 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd, * to the file's ioctl() function. */ default: - error = file_has_perm(cred, file, FILE__IOCTL); + error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd); } return error; } diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h index ddf8eec03f21..db12ff14277b 100644 --- a/security/selinux/include/avc.h +++ b/security/selinux/include/avc.h @@ -142,6 +142,7 @@ static inline int avc_audit(u32 ssid, u32 tsid, } #define AVC_STRICT 1 /* Ignore permissive mode. */ +#define AVC_EXTENDED_PERMS 2 /* update extended permissions */ int avc_has_perm_noaudit(u32 ssid, u32 tsid, u16 tclass, u32 requested, unsigned flags, @@ -151,6 +152,10 @@ int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct common_audit_data *auditdata); +int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested, + u8 driver, u8 perm, struct common_audit_data *ad); + + u32 avc_policy_seqno(void); #define AVC_CALLBACK_GRANT 1 @@ -161,6 +166,7 @@ u32 avc_policy_seqno(void); #define AVC_CALLBACK_AUDITALLOW_DISABLE 32 #define AVC_CALLBACK_AUDITDENY_ENABLE 64 #define AVC_CALLBACK_AUDITDENY_DISABLE 128 +#define AVC_CALLBACK_ADD_XPERMS 256 int avc_add_callback(int (*callback)(u32 event), u32 events); diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 36993ad1c067..6a681d26bf20 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -35,13 +35,14 @@ #define POLICYDB_VERSION_NEW_OBJECT_DEFAULTS 27 #define POLICYDB_VERSION_DEFAULT_TYPE 28 #define POLICYDB_VERSION_CONSTRAINT_NAMES 29 +#define POLICYDB_VERSION_XPERMS_IOCTL 30 /* Range of policy versions we understand*/ #define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE #ifdef CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX #define POLICYDB_VERSION_MAX CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE #else -#define POLICYDB_VERSION_MAX POLICYDB_VERSION_CONSTRAINT_NAMES +#define POLICYDB_VERSION_MAX POLICYDB_VERSION_XPERMS_IOCTL #endif /* Mask for just the mount related flags */ @@ -109,11 +110,38 @@ struct av_decision { u32 flags; }; +#define XPERMS_ALLOWED 1 +#define XPERMS_AUDITALLOW 2 +#define XPERMS_DONTAUDIT 4 + +#define security_xperm_set(perms, x) (perms[x >> 5] |= 1 << (x & 0x1f)) +#define security_xperm_test(perms, x) (1 & (perms[x >> 5] >> (x & 0x1f))) +struct extended_perms_data { + u32 p[8]; +}; + +struct extended_perms_decision { + u8 used; + u8 driver; + struct extended_perms_data *allowed; + struct extended_perms_data *auditallow; + struct extended_perms_data *dontaudit; +}; + +struct extended_perms { + u16 len; /* length associated decision chain */ + struct extended_perms_data drivers; /* flag drivers that are used */ +}; + /* definitions of av_decision.flags */ #define AVD_FLAGS_PERMISSIVE 0x0001 void security_compute_av(u32 ssid, u32 tsid, - u16 tclass, struct av_decision *avd); + u16 tclass, struct av_decision *avd, + struct extended_perms *xperms); + +void security_compute_xperms_decision(u32 ssid, u32 tsid, u16 tclass, + u8 driver, struct extended_perms_decision *xpermd); void security_compute_av_user(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd); diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c index b64f2772b030..3628d3a868b6 100644 --- a/security/selinux/ss/avtab.c +++ b/security/selinux/ss/avtab.c @@ -24,6 +24,7 @@ #include "policydb.h" static struct kmem_cache *avtab_node_cachep; +static struct kmem_cache *avtab_xperms_cachep; /* Based on MurmurHash3, written by Austin Appleby and placed in the * public domain. @@ -70,11 +71,24 @@ avtab_insert_node(struct avtab *h, int hvalue, struct avtab_key *key, struct avtab_datum *datum) { struct avtab_node *newnode; + struct avtab_extended_perms *xperms; newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL); if (newnode == NULL) return NULL; newnode->key = *key; - newnode->datum = *datum; + + if (key->specified & AVTAB_XPERMS) { + xperms = kmem_cache_zalloc(avtab_xperms_cachep, GFP_KERNEL); + if (xperms == NULL) { + kmem_cache_free(avtab_node_cachep, newnode); + return NULL; + } + *xperms = *(datum->u.xperms); + newnode->datum.u.xperms = xperms; + } else { + newnode->datum.u.data = datum->u.data; + } + if (prev) { newnode->next = prev->next; prev->next = newnode; @@ -107,8 +121,12 @@ static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_dat if (key->source_type == cur->key.source_type && key->target_type == cur->key.target_type && key->target_class == cur->key.target_class && - (specified & cur->key.specified)) + (specified & cur->key.specified)) { + /* extended perms may not be unique */ + if (specified & AVTAB_XPERMS) + break; return -EEXIST; + } if (key->source_type < cur->key.source_type) break; if (key->source_type == cur->key.source_type && @@ -271,6 +289,9 @@ void avtab_destroy(struct avtab *h) while (cur) { temp = cur; cur = cur->next; + if (temp->key.specified & AVTAB_XPERMS) + kmem_cache_free(avtab_xperms_cachep, + temp->datum.u.xperms); kmem_cache_free(avtab_node_cachep, temp); } } @@ -359,7 +380,10 @@ static uint16_t spec_order[] = { AVTAB_AUDITALLOW, AVTAB_TRANSITION, AVTAB_CHANGE, - AVTAB_MEMBER + AVTAB_MEMBER, + AVTAB_XPERMS_ALLOWED, + AVTAB_XPERMS_AUDITALLOW, + AVTAB_XPERMS_DONTAUDIT }; int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, @@ -369,10 +393,11 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, { __le16 buf16[4]; u16 enabled; - __le32 buf32[7]; u32 items, items2, val, vers = pol->policyvers; struct avtab_key key; struct avtab_datum datum; + struct avtab_extended_perms xperms; + __le32 buf32[ARRAY_SIZE(xperms.perms.p)]; int i, rc; unsigned set; @@ -429,11 +454,15 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, printk(KERN_ERR "SELinux: avtab: entry has both access vectors and types\n"); return -EINVAL; } + if (val & AVTAB_XPERMS) { + printk(KERN_ERR "SELinux: avtab: entry has extended permissions\n"); + return -EINVAL; + } for (i = 0; i < ARRAY_SIZE(spec_order); i++) { if (val & spec_order[i]) { key.specified = spec_order[i] | enabled; - datum.data = le32_to_cpu(buf32[items++]); + datum.u.data = le32_to_cpu(buf32[items++]); rc = insertf(a, &key, &datum, p); if (rc) return rc; @@ -476,14 +505,42 @@ int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, return -EINVAL; } - rc = next_entry(buf32, fp, sizeof(u32)); - if (rc) { - printk(KERN_ERR "SELinux: avtab: truncated entry\n"); - return rc; + if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) && + (key.specified & AVTAB_XPERMS)) { + printk(KERN_ERR "SELinux: avtab: policy version %u does not " + "support extended permissions rules and one " + "was specified\n", vers); + return -EINVAL; + } else if (key.specified & AVTAB_XPERMS) { + memset(&xperms, 0, sizeof(struct avtab_extended_perms)); + rc = next_entry(&xperms.specified, fp, sizeof(u8)); + if (rc) { + printk(KERN_ERR "SELinux: avtab: truncated entry\n"); + return rc; + } + rc = next_entry(&xperms.driver, fp, sizeof(u8)); + if (rc) { + printk(KERN_ERR "SELinux: avtab: truncated entry\n"); + return rc; + } + rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p)); + if (rc) { + printk(KERN_ERR "SELinux: avtab: truncated entry\n"); + return rc; + } + for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++) + xperms.perms.p[i] = le32_to_cpu(buf32[i]); + datum.u.xperms = &xperms; + } else { + rc = next_entry(buf32, fp, sizeof(u32)); + if (rc) { + printk(KERN_ERR "SELinux: avtab: truncated entry\n"); + return rc; + } + datum.u.data = le32_to_cpu(*buf32); } - datum.data = le32_to_cpu(*buf32); if ((key.specified & AVTAB_TYPE) && - !policydb_type_isvalid(pol, datum.data)) { + !policydb_type_isvalid(pol, datum.u.data)) { printk(KERN_ERR "SELinux: avtab: invalid type\n"); return -EINVAL; } @@ -543,8 +600,9 @@ int avtab_read(struct avtab *a, void *fp, struct policydb *pol) int avtab_write_item(struct policydb *p, struct avtab_node *cur, void *fp) { __le16 buf16[4]; - __le32 buf32[1]; + __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)]; int rc; + unsigned int i; buf16[0] = cpu_to_le16(cur->key.source_type); buf16[1] = cpu_to_le16(cur->key.target_type); @@ -553,8 +611,22 @@ int avtab_write_item(struct policydb *p, struct avtab_node *cur, void *fp) rc = put_entry(buf16, sizeof(u16), 4, fp); if (rc) return rc; - buf32[0] = cpu_to_le32(cur->datum.data); - rc = put_entry(buf32, sizeof(u32), 1, fp); + + if (cur->key.specified & AVTAB_XPERMS) { + rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp); + if (rc) + return rc; + rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp); + if (rc) + return rc; + for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++) + buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]); + rc = put_entry(buf32, sizeof(u32), + ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp); + } else { + buf32[0] = cpu_to_le32(cur->datum.u.data); + rc = put_entry(buf32, sizeof(u32), 1, fp); + } if (rc) return rc; return 0; @@ -588,9 +660,13 @@ void avtab_cache_init(void) avtab_node_cachep = kmem_cache_create("avtab_node", sizeof(struct avtab_node), 0, SLAB_PANIC, NULL); + avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms", + sizeof(struct avtab_extended_perms), + 0, SLAB_PANIC, NULL); } void avtab_cache_destroy(void) { kmem_cache_destroy(avtab_node_cachep); + kmem_cache_destroy(avtab_xperms_cachep); } diff --git a/security/selinux/ss/avtab.h b/security/selinux/ss/avtab.h index adb451cd44f9..d946c9dc3c9c 100644 --- a/security/selinux/ss/avtab.h +++ b/security/selinux/ss/avtab.h @@ -23,6 +23,7 @@ #ifndef _SS_AVTAB_H_ #define _SS_AVTAB_H_ +#include "security.h" #include struct avtab_key { @@ -37,13 +38,43 @@ struct avtab_key { #define AVTAB_MEMBER 0x0020 #define AVTAB_CHANGE 0x0040 #define AVTAB_TYPE (AVTAB_TRANSITION | AVTAB_MEMBER | AVTAB_CHANGE) +/* extended permissions */ +#define AVTAB_XPERMS_ALLOWED 0x0100 +#define AVTAB_XPERMS_AUDITALLOW 0x0200 +#define AVTAB_XPERMS_DONTAUDIT 0x0400 +#define AVTAB_XPERMS (AVTAB_XPERMS_ALLOWED | \ + AVTAB_XPERMS_AUDITALLOW | \ + AVTAB_XPERMS_DONTAUDIT) #define AVTAB_ENABLED_OLD 0x80000000 /* reserved for used in cond_avtab */ #define AVTAB_ENABLED 0x8000 /* reserved for used in cond_avtab */ u16 specified; /* what field is specified */ }; +/* + * For operations that require more than the 32 permissions provided by the avc + * extended permissions may be used to provide 256 bits of permissions. + */ +struct avtab_extended_perms { +/* These are not flags. All 256 values may be used */ +#define AVTAB_XPERMS_IOCTLFUNCTION 0x01 +#define AVTAB_XPERMS_IOCTLDRIVER 0x02 + /* extension of the avtab_key specified */ + u8 specified; /* ioctl, netfilter, ... */ + /* + * if 256 bits is not adequate as is often the case with ioctls, then + * multiple extended perms may be used and the driver field + * specifies which permissions are included. + */ + u8 driver; + /* 256 bits of permissions */ + struct extended_perms_data perms; +}; + struct avtab_datum { - u32 data; /* access vector or type value */ + union { + u32 data; /* access vector or type value */ + struct avtab_extended_perms *xperms; + } u; }; struct avtab_node { diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c index 62c6773be0b7..18643bf9894d 100644 --- a/security/selinux/ss/conditional.c +++ b/security/selinux/ss/conditional.c @@ -15,6 +15,7 @@ #include "security.h" #include "conditional.h" +#include "services.h" /* * cond_evaluate_expr evaluates a conditional expr @@ -612,21 +613,39 @@ int cond_write_list(struct policydb *p, struct cond_node *list, void *fp) return 0; } -/* Determine whether additional permissions are granted by the conditional - * av table, and if so, add them to the result - */ -void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd) + +void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key, + struct extended_perms_decision *xpermd) { struct avtab_node *node; - if (!ctab || !key || !avd) + if (!ctab || !key || !xpermd) + return; + + for (node = avtab_search_node(ctab, key); node; + node = avtab_search_node_next(node, key->specified)) { + if (node->key.specified & AVTAB_ENABLED) + services_compute_xperms_decision(xpermd, node); + } + return; + +} +/* Determine whether additional permissions are granted by the conditional + * av table, and if so, add them to the result + */ +void cond_compute_av(struct avtab *ctab, struct avtab_key *key, + struct av_decision *avd, struct extended_perms *xperms) +{ + struct avtab_node *node; + + if (!ctab || !key || !avd || !xperms) return; for (node = avtab_search_node(ctab, key); node; node = avtab_search_node_next(node, key->specified)) { if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) == (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED))) - avd->allowed |= node->datum.data; + avd->allowed |= node->datum.u.data; if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) == (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED))) /* Since a '0' in an auditdeny mask represents a @@ -634,10 +653,13 @@ void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decisi * the '&' operand to ensure that all '0's in the mask * are retained (much unlike the allow and auditallow cases). */ - avd->auditdeny &= node->datum.data; + avd->auditdeny &= node->datum.u.data; if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) == (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED))) - avd->auditallow |= node->datum.data; + avd->auditallow |= node->datum.u.data; + if ((node->key.specified & AVTAB_ENABLED) && + (node->key.specified & AVTAB_XPERMS)) + services_compute_xperms_drivers(xperms, node); } return; } diff --git a/security/selinux/ss/conditional.h b/security/selinux/ss/conditional.h index 4d1f87466508..ddb43e7e1c75 100644 --- a/security/selinux/ss/conditional.h +++ b/security/selinux/ss/conditional.h @@ -73,8 +73,10 @@ int cond_read_list(struct policydb *p, void *fp); int cond_write_bool(void *key, void *datum, void *ptr); int cond_write_list(struct policydb *p, struct cond_node *list, void *fp); -void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd); - +void cond_compute_av(struct avtab *ctab, struct avtab_key *key, + struct av_decision *avd, struct extended_perms *xperms); +void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key, + struct extended_perms_decision *xpermd); int evaluate_cond_node(struct policydb *p, struct cond_node *node); #endif /* _CONDITIONAL_H_ */ diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 74aa224267c1..992a31530825 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -148,6 +148,11 @@ static struct policydb_compat_info policydb_compat[] = { .sym_num = SYM_NUM, .ocon_num = OCON_NUM, }, + { + .version = POLICYDB_VERSION_XPERMS_IOCTL, + .sym_num = SYM_NUM, + .ocon_num = OCON_NUM, + }, }; static struct policydb_compat_info *policydb_lookup_compat(int version) diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 9e2d82070915..b7df12ba61d8 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -93,9 +93,10 @@ static int context_struct_to_string(struct context *context, char **scontext, u32 *scontext_len); static void context_struct_compute_av(struct context *scontext, - struct context *tcontext, - u16 tclass, - struct av_decision *avd); + struct context *tcontext, + u16 tclass, + struct av_decision *avd, + struct extended_perms *xperms); struct selinux_mapping { u16 value; /* policy value */ @@ -565,7 +566,8 @@ static void type_attribute_bounds_av(struct context *scontext, context_struct_compute_av(&lo_scontext, tcontext, tclass, - &lo_avd); + &lo_avd, + NULL); if ((lo_avd.allowed & avd->allowed) == avd->allowed) return; /* no masked permission */ masked = ~lo_avd.allowed & avd->allowed; @@ -580,7 +582,8 @@ static void type_attribute_bounds_av(struct context *scontext, context_struct_compute_av(scontext, &lo_tcontext, tclass, - &lo_avd); + &lo_avd, + NULL); if ((lo_avd.allowed & avd->allowed) == avd->allowed) return; /* no masked permission */ masked = ~lo_avd.allowed & avd->allowed; @@ -596,7 +599,8 @@ static void type_attribute_bounds_av(struct context *scontext, context_struct_compute_av(&lo_scontext, &lo_tcontext, tclass, - &lo_avd); + &lo_avd, + NULL); if ((lo_avd.allowed & avd->allowed) == avd->allowed) return; /* no masked permission */ masked = ~lo_avd.allowed & avd->allowed; @@ -613,13 +617,39 @@ static void type_attribute_bounds_av(struct context *scontext, } /* - * Compute access vectors based on a context structure pair for - * the permissions in a particular class. + * flag which drivers have permissions + * only looking for ioctl based extended permssions + */ +void services_compute_xperms_drivers( + struct extended_perms *xperms, + struct avtab_node *node) +{ + unsigned int i; + + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) { + /* if one or more driver has all permissions allowed */ + for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++) + xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i]; + } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) { + /* if allowing permissions within a driver */ + security_xperm_set(xperms->drivers.p, + node->datum.u.xperms->driver); + } + + /* If no ioctl commands are allowed, ignore auditallow and auditdeny */ + if (node->key.specified & AVTAB_XPERMS_ALLOWED) + xperms->len = 1; +} + +/* + * Compute access vectors and extended permissions based on a context + * structure pair for the permissions in a particular class. */ static void context_struct_compute_av(struct context *scontext, - struct context *tcontext, - u16 tclass, - struct av_decision *avd) + struct context *tcontext, + u16 tclass, + struct av_decision *avd, + struct extended_perms *xperms) { struct constraint_node *constraint; struct role_allow *ra; @@ -633,6 +663,10 @@ static void context_struct_compute_av(struct context *scontext, avd->allowed = 0; avd->auditallow = 0; avd->auditdeny = 0xffffffff; + if (xperms) { + memset(&xperms->drivers, 0, sizeof(xperms->drivers)); + xperms->len = 0; + } if (unlikely(!tclass || tclass > policydb.p_classes.nprim)) { if (printk_ratelimit()) @@ -647,7 +681,7 @@ static void context_struct_compute_av(struct context *scontext, * this permission check, then use it. */ avkey.target_class = tclass; - avkey.specified = AVTAB_AV; + avkey.specified = AVTAB_AV | AVTAB_XPERMS; sattr = flex_array_get(policydb.type_attr_map_array, scontext->type - 1); BUG_ON(!sattr); tattr = flex_array_get(policydb.type_attr_map_array, tcontext->type - 1); @@ -660,15 +694,18 @@ static void context_struct_compute_av(struct context *scontext, node; node = avtab_search_node_next(node, avkey.specified)) { if (node->key.specified == AVTAB_ALLOWED) - avd->allowed |= node->datum.data; + avd->allowed |= node->datum.u.data; else if (node->key.specified == AVTAB_AUDITALLOW) - avd->auditallow |= node->datum.data; + avd->auditallow |= node->datum.u.data; else if (node->key.specified == AVTAB_AUDITDENY) - avd->auditdeny &= node->datum.data; + avd->auditdeny &= node->datum.u.data; + else if (xperms && (node->key.specified & AVTAB_XPERMS)) + services_compute_xperms_drivers(xperms, node); } /* Check conditional av table for additional permissions */ - cond_compute_av(&policydb.te_cond_avtab, &avkey, avd); + cond_compute_av(&policydb.te_cond_avtab, &avkey, + avd, xperms); } } @@ -899,6 +936,139 @@ static void avd_init(struct av_decision *avd) avd->flags = 0; } +void services_compute_xperms_decision(struct extended_perms_decision *xpermd, + struct avtab_node *node) +{ + unsigned int i; + + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) { + if (xpermd->driver != node->datum.u.xperms->driver) + return; + } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) { + if (!security_xperm_test(node->datum.u.xperms->perms.p, + xpermd->driver)) + return; + } else { + BUG(); + } + + if (node->key.specified == AVTAB_XPERMS_ALLOWED) { + xpermd->used |= XPERMS_ALLOWED; + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) { + memset(xpermd->allowed->p, 0xff, + sizeof(xpermd->allowed->p)); + } + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) { + for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++) + xpermd->allowed->p[i] |= + node->datum.u.xperms->perms.p[i]; + } + } else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) { + xpermd->used |= XPERMS_AUDITALLOW; + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) { + memset(xpermd->auditallow->p, 0xff, + sizeof(xpermd->auditallow->p)); + } + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) { + for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++) + xpermd->auditallow->p[i] |= + node->datum.u.xperms->perms.p[i]; + } + } else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) { + xpermd->used |= XPERMS_DONTAUDIT; + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) { + memset(xpermd->dontaudit->p, 0xff, + sizeof(xpermd->dontaudit->p)); + } + if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) { + for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++) + xpermd->dontaudit->p[i] |= + node->datum.u.xperms->perms.p[i]; + } + } else { + BUG(); + } +} + +void security_compute_xperms_decision(u32 ssid, + u32 tsid, + u16 orig_tclass, + u8 driver, + struct extended_perms_decision *xpermd) +{ + u16 tclass; + struct context *scontext, *tcontext; + struct avtab_key avkey; + struct avtab_node *node; + struct ebitmap *sattr, *tattr; + struct ebitmap_node *snode, *tnode; + unsigned int i, j; + + xpermd->driver = driver; + xpermd->used = 0; + memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p)); + memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p)); + memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p)); + + read_lock(&policy_rwlock); + if (!ss_initialized) + goto allow; + + scontext = sidtab_search(&sidtab, ssid); + if (!scontext) { + printk(KERN_ERR "SELinux: %s: unrecognized SID %d\n", + __func__, ssid); + goto out; + } + + tcontext = sidtab_search(&sidtab, tsid); + if (!tcontext) { + printk(KERN_ERR "SELinux: %s: unrecognized SID %d\n", + __func__, tsid); + goto out; + } + + tclass = unmap_class(orig_tclass); + if (unlikely(orig_tclass && !tclass)) { + if (policydb.allow_unknown) + goto allow; + goto out; + } + + + if (unlikely(!tclass || tclass > policydb.p_classes.nprim)) { + pr_warn_ratelimited("SELinux: Invalid class %hu\n", tclass); + goto out; + } + + avkey.target_class = tclass; + avkey.specified = AVTAB_XPERMS; + sattr = flex_array_get(policydb.type_attr_map_array, + scontext->type - 1); + BUG_ON(!sattr); + tattr = flex_array_get(policydb.type_attr_map_array, + tcontext->type - 1); + BUG_ON(!tattr); + ebitmap_for_each_positive_bit(sattr, snode, i) { + ebitmap_for_each_positive_bit(tattr, tnode, j) { + avkey.source_type = i + 1; + avkey.target_type = j + 1; + for (node = avtab_search_node(&policydb.te_avtab, &avkey); + node; + node = avtab_search_node_next(node, avkey.specified)) + services_compute_xperms_decision(xpermd, node); + + cond_compute_xperms(&policydb.te_cond_avtab, + &avkey, xpermd); + } + } +out: + read_unlock(&policy_rwlock); + return; +allow: + memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p)); + goto out; +} /** * security_compute_av - Compute access vector decisions. @@ -906,6 +1076,7 @@ static void avd_init(struct av_decision *avd) * @tsid: target security identifier * @tclass: target security class * @avd: access vector decisions + * @xperms: extended permissions * * Compute a set of access vector decisions based on the * SID pair (@ssid, @tsid) for the permissions in @tclass. @@ -913,13 +1084,15 @@ static void avd_init(struct av_decision *avd) void security_compute_av(u32 ssid, u32 tsid, u16 orig_tclass, - struct av_decision *avd) + struct av_decision *avd, + struct extended_perms *xperms) { u16 tclass; struct context *scontext = NULL, *tcontext = NULL; read_lock(&policy_rwlock); avd_init(avd); + xperms->len = 0; if (!ss_initialized) goto allow; @@ -947,7 +1120,7 @@ void security_compute_av(u32 ssid, goto allow; goto out; } - context_struct_compute_av(scontext, tcontext, tclass, avd); + context_struct_compute_av(scontext, tcontext, tclass, avd, xperms); map_decision(orig_tclass, avd, policydb.allow_unknown); out: read_unlock(&policy_rwlock); @@ -993,7 +1166,7 @@ void security_compute_av_user(u32 ssid, goto out; } - context_struct_compute_av(scontext, tcontext, tclass, avd); + context_struct_compute_av(scontext, tcontext, tclass, avd, NULL); out: read_unlock(&policy_rwlock); return; @@ -1515,7 +1688,7 @@ static int security_compute_sid(u32 ssid, if (avdatum) { /* Use the type from the type transition/member/change rule. */ - newcontext.type = avdatum->data; + newcontext.type = avdatum->u.data; } /* if we have a objname this is a file trans check so check those rules */ diff --git a/security/selinux/ss/services.h b/security/selinux/ss/services.h index e8d907e903cd..6abcd8729ec3 100644 --- a/security/selinux/ss/services.h +++ b/security/selinux/ss/services.h @@ -11,5 +11,11 @@ extern struct policydb policydb; +void services_compute_xperms_drivers(struct extended_perms *xperms, + struct avtab_node *node); + +void services_compute_xperms_decision(struct extended_perms_decision *xpermd, + struct avtab_node *node); + #endif /* _SS_SERVICES_H_ */ From 9629d04ae06812f217846b69728c969afee690b4 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 10 Jul 2015 17:19:56 -0400 Subject: [PATCH 3/7] selinux: reduce locking overhead in inode_free_security() The inode_free_security() function just took the superblock's isec_lock before checking and trying to remove the inode security struct from the linked list. In many cases, the list was empty and so the lock taking is wasteful as no useful work is done. On multi-socket systems with a large number of CPUs, there can also be a fair amount of spinlock contention on the isec_lock if many tasks are exiting at the same time. This patch changes the code to check the state of the list first before taking the lock and attempting to dequeue it. The list_del_init() can be called more than once on the same list with no harm as long as they are properly serialized. It should not be possible to have inode_free_security() called concurrently with list_add(). For better safety, however, we use list_empty_careful() here even though it is still not completely safe in case that happens. Signed-off-by: Waiman Long Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a049b7216270..4de09f0227b4 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -254,10 +254,21 @@ static void inode_free_security(struct inode *inode) struct inode_security_struct *isec = inode->i_security; struct superblock_security_struct *sbsec = inode->i_sb->s_security; - spin_lock(&sbsec->isec_lock); - if (!list_empty(&isec->list)) + /* + * As not all inode security structures are in a list, we check for + * empty list outside of the lock to make sure that we won't waste + * time taking a lock doing nothing. + * + * The list_del_init() function can be safely called more than once. + * It should not be possible for this function to be called with + * concurrent list_add(), but for better safety against future changes + * in the code, we use list_empty_careful() here. + */ + if (!list_empty_careful(&isec->list)) { + spin_lock(&sbsec->isec_lock); list_del_init(&isec->list); - spin_unlock(&sbsec->isec_lock); + spin_unlock(&sbsec->isec_lock); + } /* * The inode may still be referenced in a path walk and From 5dee25d08eac01472904b0ab32ce35edee5c0518 Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Fri, 10 Jul 2015 17:19:57 -0400 Subject: [PATCH 4/7] selinux: initialize sock security class to default value Initialize the security class of sock security structures to the generic socket class. This is similar to what is already done in inode_alloc_security for files. Generally the sclass field will later by set by socket_post_create or sk_clone or sock_graft, but for protocol implementations that fail to call any of these for newly accepted sockets, we want some sane default that will yield a legitimate avc denied message with non-garbage values for class and permission. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 1 + 1 file changed, 1 insertion(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 4de09f0227b4..ef310f82717d 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4559,6 +4559,7 @@ static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority sksec->peer_sid = SECINITSID_UNLABELED; sksec->sid = SECINITSID_UNLABELED; + sksec->sclass = SECCLASS_SOCKET; selinux_netlbl_sk_security_reset(sksec); sk->sk_security = sksec; From bd1741f4cf05d7709348f591d16eeb5f786de673 Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Fri, 10 Jul 2015 17:19:57 -0400 Subject: [PATCH 5/7] selinux: Augment BUG_ON assertion for secclass_map. Ensure that we catch any cases where tclass == 0. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/avc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/security/selinux/avc.c b/security/selinux/avc.c index 2d5e1b04cd50..324acc62f7e0 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -116,6 +116,7 @@ static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) return; } + BUG_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map)); perms = secclass_map[tclass-1].perms; audit_log_format(ab, " {"); @@ -164,7 +165,7 @@ static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tcla kfree(scontext); } - BUG_ON(tclass >= ARRAY_SIZE(secclass_map)); + BUG_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map)); audit_log_format(ab, " tclass=%s", secclass_map[tclass-1].name); } From c3c188b2c3ed29effe8693672ee1c84184103b4e Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 10 Jul 2015 17:19:58 -0400 Subject: [PATCH 6/7] selinux: Create a common helper to determine an inode label [ver #3] Create a common helper function to determine the label for a new inode. This is then used by: - may_create() - selinux_dentry_init_security() - selinux_inode_init_security() This will change the behaviour of the functions slightly, bringing them all into line. Suggested-by: Stephen Smalley Signed-off-by: David Howells Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 87 +++++++++++++++++++--------------------- 1 file changed, 41 insertions(+), 46 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index ef310f82717d..f4be0a110788 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1709,6 +1709,32 @@ static int file_has_perm(const struct cred *cred, return rc; } +/* + * Determine the label for an inode that might be unioned. + */ +static int selinux_determine_inode_label(const struct inode *dir, + const struct qstr *name, + u16 tclass, + u32 *_new_isid) +{ + const struct superblock_security_struct *sbsec = dir->i_sb->s_security; + const struct inode_security_struct *dsec = dir->i_security; + const struct task_security_struct *tsec = current_security(); + + if ((sbsec->flags & SE_SBINITIALIZED) && + (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) { + *_new_isid = sbsec->mntpoint_sid; + } else if ((sbsec->flags & SBLABEL_MNT) && + tsec->create_sid) { + *_new_isid = tsec->create_sid; + } else { + return security_transition_sid(tsec->sid, dsec->sid, tclass, + name, _new_isid); + } + + return 0; +} + /* Check whether a task can create a file. */ static int may_create(struct inode *dir, struct dentry *dentry, @@ -1725,7 +1751,6 @@ static int may_create(struct inode *dir, sbsec = dir->i_sb->s_security; sid = tsec->sid; - newsid = tsec->create_sid; ad.type = LSM_AUDIT_DATA_DENTRY; ad.u.dentry = dentry; @@ -1736,12 +1761,10 @@ static int may_create(struct inode *dir, if (rc) return rc; - if (!newsid || !(sbsec->flags & SBLABEL_MNT)) { - rc = security_transition_sid(sid, dsec->sid, tclass, - &dentry->d_name, &newsid); - if (rc) - return rc; - } + rc = selinux_determine_inode_label(dir, &dentry->d_name, tclass, + &newsid); + if (rc) + return rc; rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad); if (rc) @@ -2715,32 +2738,14 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode, struct qstr *name, void **ctx, u32 *ctxlen) { - const struct cred *cred = current_cred(); - struct task_security_struct *tsec; - struct inode_security_struct *dsec; - struct superblock_security_struct *sbsec; - struct inode *dir = d_backing_inode(dentry->d_parent); u32 newsid; int rc; - tsec = cred->security; - dsec = dir->i_security; - sbsec = dir->i_sb->s_security; - - if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) { - newsid = tsec->create_sid; - } else { - rc = security_transition_sid(tsec->sid, dsec->sid, - inode_mode_to_security_class(mode), - name, - &newsid); - if (rc) { - printk(KERN_WARNING - "%s: security_transition_sid failed, rc=%d\n", - __func__, -rc); - return rc; - } - } + rc = selinux_determine_inode_label(d_inode(dentry->d_parent), name, + inode_mode_to_security_class(mode), + &newsid); + if (rc) + return rc; return security_sid_to_context(newsid, (char **)ctx, ctxlen); } @@ -2763,22 +2768,12 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, sid = tsec->sid; newsid = tsec->create_sid; - if ((sbsec->flags & SE_SBINITIALIZED) && - (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) - newsid = sbsec->mntpoint_sid; - else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) { - rc = security_transition_sid(sid, dsec->sid, - inode_mode_to_security_class(inode->i_mode), - qstr, &newsid); - if (rc) { - printk(KERN_WARNING "%s: " - "security_transition_sid failed, rc=%d (dev=%s " - "ino=%ld)\n", - __func__, - -rc, inode->i_sb->s_id, inode->i_ino); - return rc; - } - } + rc = selinux_determine_inode_label( + dir, qstr, + inode_mode_to_security_class(inode->i_mode), + &newsid); + if (rc) + return rc; /* Possibly defer initialization to selinux_complete_init. */ if (sbsec->flags & SE_SBINITIALIZED) { From fda4d578ed0a7e1d116f56a15efea0e4ba78acad Mon Sep 17 00:00:00 2001 From: Laurent Bigonville Date: Tue, 7 Jul 2015 23:10:52 +0200 Subject: [PATCH 7/7] selinux: explicitly declare the role "base_r" This fixes the compilation of policy generated by mdp with the recent version of checkpolicy. Signed-off-by: Laurent Bigonville Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- scripts/selinux/mdp/mdp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/scripts/selinux/mdp/mdp.c b/scripts/selinux/mdp/mdp.c index 62b34ce1f50d..e10beb11b696 100644 --- a/scripts/selinux/mdp/mdp.c +++ b/scripts/selinux/mdp/mdp.c @@ -98,6 +98,7 @@ int main(int argc, char *argv[]) /* types, roles, and allows */ fprintf(fout, "type base_t;\n"); + fprintf(fout, "role base_r;\n"); fprintf(fout, "role base_r types { base_t };\n"); for (i = 0; secclass_map[i].name; i++) fprintf(fout, "allow base_t base_t:%s *;\n",