diff options
Diffstat (limited to 'security/selinux')
| -rw-r--r-- | security/selinux/avc.c | 8 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 40 | ||||
| -rw-r--r-- | security/selinux/include/avc.h | 6 | ||||
| -rw-r--r-- | security/selinux/ss/services.c | 142 |
4 files changed, 160 insertions, 36 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c index b2ab60859832..236aaa2ea86d 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -137,7 +137,7 @@ static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) * @tclass: target security class * @av: access vector */ -void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) +static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) { const char **common_pts = NULL; u32 common_base = 0; @@ -970,3 +970,9 @@ u32 avc_policy_seqno(void) { return avc_cache.latest_notif; } + +void avc_disable(void) +{ + if (avc_node_cachep) + kmem_cache_destroy(avc_node_cachep); +} diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 15c2a08a66f1..5dee88362e71 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1854,12 +1854,12 @@ static inline u32 open_file_to_av(struct file *file) /* Hook functions begin here. */ -static int selinux_ptrace_may_access(struct task_struct *child, +static int selinux_ptrace_access_check(struct task_struct *child, unsigned int mode) { int rc; - rc = cap_ptrace_may_access(child, mode); + rc = cap_ptrace_access_check(child, mode); if (rc) return rc; @@ -2938,11 +2938,6 @@ static int selinux_revalidate_file_permission(struct file *file, int mask) const struct cred *cred = current_cred(); struct inode *inode = file->f_path.dentry->d_inode; - if (!mask) { - /* No permission to check. Existence test. */ - return 0; - } - /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */ if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE)) mask |= MAY_APPEND; @@ -2953,10 +2948,20 @@ static int selinux_revalidate_file_permission(struct file *file, int mask) static int selinux_file_permission(struct file *file, int mask) { + struct inode *inode = file->f_path.dentry->d_inode; + struct file_security_struct *fsec = file->f_security; + struct inode_security_struct *isec = inode->i_security; + u32 sid = current_sid(); + if (!mask) /* No permission to check. Existence test. */ return 0; + if (sid == fsec->sid && fsec->isid == isec->sid && + fsec->pseqno == avc_policy_seqno()) + /* No change since dentry_open check. */ + return 0; + return selinux_revalidate_file_permission(file, mask); } @@ -3029,9 +3034,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot, int rc = 0; u32 sid = current_sid(); - if (addr < mmap_min_addr) + /* + * notice that we are intentionally putting the SELinux check before + * the secondary cap_file_mmap check. This is such a likely attempt + * at bad behaviour/exploit that we always want to get the AVC, even + * if DAC would have also denied the operation. + */ + if (addr < CONFIG_LSM_MMAP_MIN_ADDR) { rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT, MEMPROTECT__MMAP_ZERO, NULL); + if (rc) + return rc; + } + + /* do DAC check on address space usage */ + rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only); if (rc || addr_only) return rc; @@ -5182,7 +5199,7 @@ static int selinux_setprocattr(struct task_struct *p, /* Only allow single threaded processes to change context */ error = -EPERM; - if (!is_single_threaded(p)) { + if (!current_is_single_threaded()) { error = security_bounded_transition(tsec->sid, sid); if (error) goto abort_change; @@ -5310,7 +5327,7 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer) static struct security_operations selinux_ops = { .name = "selinux", - .ptrace_may_access = selinux_ptrace_may_access, + .ptrace_access_check = selinux_ptrace_access_check, .ptrace_traceme = selinux_ptrace_traceme, .capget = selinux_capget, .capset = selinux_capset, @@ -5678,6 +5695,9 @@ int selinux_disable(void) selinux_disabled = 1; selinux_enabled = 0; + /* Try to destroy the avc node cache */ + avc_disable(); + /* Reset security_ops to the secondary module, dummy or capability. */ security_ops = secondary_ops; diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h index d12ff1a9c0aa..ae4c3a0e2c1a 100644 --- a/security/selinux/include/avc.h +++ b/security/selinux/include/avc.h @@ -127,13 +127,13 @@ int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid, u32 events, u32 ssid, u32 tsid, u16 tclass, u32 perms); -/* Shows permission in human readable form */ -void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av); - /* Exported to selinuxfs */ int avc_get_hash_stats(char *page); extern unsigned int avc_cache_threshold; +/* Attempt to free avc node cache */ +void avc_disable(void); + #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats); #endif diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 500e6f78e115..ff17820d35ec 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -22,6 +22,11 @@ * * Added validation of kernel classes and permissions * + * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com> + * + * Added support for bounds domain and audit messaged on masked permissions + * + * Copyright (C) 2008, 2009 NEC Corporation * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P. * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc. * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC @@ -279,6 +284,95 @@ mls_ops: } /* + * security_dump_masked_av - dumps masked permissions during + * security_compute_av due to RBAC, MLS/Constraint and Type bounds. + */ +static int dump_masked_av_helper(void *k, void *d, void *args) +{ + struct perm_datum *pdatum = d; + char **permission_names = args; + + BUG_ON(pdatum->value < 1 || pdatum->value > 32); + + permission_names[pdatum->value - 1] = (char *)k; + + return 0; +} + +static void security_dump_masked_av(struct context *scontext, + struct context *tcontext, + u16 tclass, + u32 permissions, + const char *reason) +{ + struct common_datum *common_dat; + struct class_datum *tclass_dat; + struct audit_buffer *ab; + char *tclass_name; + char *scontext_name = NULL; + char *tcontext_name = NULL; + char *permission_names[32]; + int index, length; + bool need_comma = false; + + if (!permissions) + return; + + tclass_name = policydb.p_class_val_to_name[tclass - 1]; + tclass_dat = policydb.class_val_to_struct[tclass - 1]; + common_dat = tclass_dat->comdatum; + + /* init permission_names */ + if (common_dat && + hashtab_map(common_dat->permissions.table, + dump_masked_av_helper, permission_names) < 0) + goto out; + + if (hashtab_map(tclass_dat->permissions.table, + dump_masked_av_helper, permission_names) < 0) + goto out; + + /* get scontext/tcontext in text form */ + if (context_struct_to_string(scontext, + &scontext_name, &length) < 0) + goto out; + + if (context_struct_to_string(tcontext, + &tcontext_name, &length) < 0) + goto out; + + /* audit a message */ + ab = audit_log_start(current->audit_context, + GFP_ATOMIC, AUDIT_SELINUX_ERR); + if (!ab) + goto out; + + audit_log_format(ab, "op=security_compute_av reason=%s " + "scontext=%s tcontext=%s tclass=%s perms=", + reason, scontext_name, tcontext_name, tclass_name); + + for (index = 0; index < 32; index++) { + u32 mask = (1 << index); + + if ((mask & permissions) == 0) + continue; + + audit_log_format(ab, "%s%s", + need_comma ? "," : "", + permission_names[index] + ? permission_names[index] : "????"); + need_comma = true; + } + audit_log_end(ab); +out: + /* release scontext/tcontext */ + kfree(tcontext_name); + kfree(scontext_name); + + return; +} + +/* * security_boundary_permission - drops violated permissions * on boundary constraint. */ @@ -347,28 +441,12 @@ static void type_attribute_bounds_av(struct context *scontext, } if (masked) { - struct audit_buffer *ab; - char *stype_name - = policydb.p_type_val_to_name[source->value - 1]; - char *ttype_name - = policydb.p_type_val_to_name[target->value - 1]; - char *tclass_name - = policydb.p_class_val_to_name[tclass - 1]; - /* mask violated permissions */ avd->allowed &= ~masked; - /* notice to userspace via audit message */ - ab = audit_log_start(current->audit_context, - GFP_ATOMIC, AUDIT_SELINUX_ERR); - if (!ab) - return; - - audit_log_format(ab, "av boundary violation: " - "source=%s target=%s tclass=%s", - stype_name, ttype_name, tclass_name); - avc_dump_av(ab, tclass, masked); - audit_log_end(ab); + /* audit masked permissions */ + security_dump_masked_av(scontext, tcontext, + tclass, masked, "bounds"); } } @@ -480,7 +558,7 @@ static int context_struct_compute_av(struct context *scontext, if ((constraint->permissions & (avd->allowed)) && !constraint_expr_eval(scontext, tcontext, NULL, constraint->expr)) { - avd->allowed = (avd->allowed) & ~(constraint->permissions); + avd->allowed &= ~(constraint->permissions); } constraint = constraint->next; } @@ -499,8 +577,8 @@ static int context_struct_compute_av(struct context *scontext, break; } if (!ra) - avd->allowed = (avd->allowed) & ~(PROCESS__TRANSITION | - PROCESS__DYNTRANSITION); + avd->allowed &= ~(PROCESS__TRANSITION | + PROCESS__DYNTRANSITION); } /* @@ -687,6 +765,26 @@ int security_bounded_transition(u32 old_sid, u32 new_sid) } index = type->bounds; } + + if (rc) { + char *old_name = NULL; + char *new_name = NULL; + int length; + + if (!context_struct_to_string(old_context, + &old_name, &length) && + !context_struct_to_string(new_context, + &new_name, &length)) { + audit_log(current->audit_context, + GFP_ATOMIC, AUDIT_SELINUX_ERR, + "op=security_bounded_transition " + "result=denied " + "oldcontext=%s newcontext=%s", + old_name, new_name); + } + kfree(new_name); + kfree(old_name); + } out: read_unlock(&policy_rwlock); |