// SPDX-License-Identifier: GPL-2.0-only/* * AppArmor security module * * This file contains basic common functions used in AppArmor * * Copyright (C) 1998-2008 Novell/SUSE * Copyright 2009-2010 Canonical Ltd. */ #include <linux/ctype.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/vmalloc.h> #include "include/audit.h"#include "include/apparmor.h"#include "include/lib.h"#include "include/perms.h"#include "include/policy.h" struct aa_perms nullperms;struct aa_perms allperms = { .allow = ALL_PERMS_MASK,			     .quiet = ALL_PERMS_MASK,			     .hide = ALL_PERMS_MASK }; /** * aa_free_str_table - free entries str table * @t: the string table to free  (MAYBE NULL) */void aa_free_str_table(struct aa_str_table *t){	int i; 	if (t) {		if (!t->table)			return; 		for (i = 0; i < t->size; i++)			kfree_sensitive(t->table[i]);		kfree_sensitive(t->table);		t->table = NULL;		t->size = 0;	}} /** * skipn_spaces - Removes leading whitespace from @str. * @str: The string to be stripped. * @n: length of str to parse, will stop at \0 if encountered before n * * Returns a pointer to the first non-whitespace character in @str. * if all whitespace will return NULL */ const char *skipn_spaces(const char *str, size_t n){	for (; n && isspace(*str); --n)		++str;	if (n)		return (char *)str;	return NULL;} const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,			     size_t *ns_len){	const char *end = fqname + n;	const char *name = skipn_spaces(fqname, n); 	*ns_name = NULL;	*ns_len = 0; 	if (!name)		return NULL; 	if (name[0] == ':') {		char *split = strnchr(&name[1], end - &name[1], ':');		*ns_name = skipn_spaces(&name[1], end - &name[1]);		if (!*ns_name)			return NULL;		if (split) {			*ns_len = split - *ns_name;			if (*ns_len == 0)				*ns_name = NULL;			split++;			if (end - split > 1 && strncmp(split, "//", 2) == 0)				split += 2;			name = skipn_spaces(split, end - split);		} else {			/* a ns name without a following profile is allowed */			name = NULL;			*ns_len = end - *ns_name;		}	}	if (name && *name == 0)		name = NULL; 	return name;} /** * aa_info_message - log a none profile related status message * @str: message to log */void aa_info_message(const char *str){	if (audit_enabled) {		DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_NONE, NULL); 		ad.info = str;		aa_audit_msg(AUDIT_APPARMOR_STATUS, &ad, NULL);	}	printk(KERN_INFO "AppArmor: %s\n", str);} __counted char *aa_str_alloc(int size, gfp_t gfp){	struct counted_str *str; 	str = kmalloc(struct_size(str, name, size), gfp);	if (!str)		return NULL; 	kref_init(&str->count);	return str->name;} void aa_str_kref(struct kref *kref){	kfree(container_of(kref, struct counted_str, count));}  const char aa_file_perm_chrs[] = "xwracd         km l     ";const char *aa_file_perm_names[] = {	"exec",	"write",	"read",	"append", 	"create",	"delete",	"open",	"rename", 	"setattr",	"getattr",	"setcred",	"getcred", 	"chmod",	"chown",	"chgrp",	"lock", 	"mmap",	"mprot",	"link",	"snapshot", 	"unknown",	"unknown",	"unknown",	"unknown", 	"unknown",	"unknown",	"unknown",	"unknown", 	"stack",	"change_onexec",	"change_profile",	"change_hat",}; /** * aa_perm_mask_to_str - convert a perm mask to its short string * @str: character buffer to store string in (at least 10 characters) * @str_size: size of the @str buffer * @chrs: NUL-terminated character buffer of permission characters * @mask: permission mask to convert */void aa_perm_mask_to_str(char *str, size_t str_size, const char *chrs, u32 mask){	unsigned int i, perm = 1;	size_t num_chrs = strlen(chrs); 	for (i = 0; i < num_chrs; perm <<= 1, i++) {		if (mask & perm) {			/* Ensure that one byte is left for NUL-termination */			if (WARN_ON_ONCE(str_size <= 1))				break; 			*str++ = chrs[i];			str_size--;		}	}	*str = '\0';} void aa_audit_perm_names(struct audit_buffer *ab, const char * const *names,			 u32 mask){	const char *fmt = "%s";	unsigned int i, perm = 1;	bool prev = false; 	for (i = 0; i < 32; perm <<= 1, i++) {		if (mask & perm) {			audit_log_format(ab, fmt, names[i]);			if (!prev) {				prev = true;				fmt = " %s";			}		}	}} void aa_audit_perm_mask(struct audit_buffer *ab, u32 mask, const char *chrs,			u32 chrsmask, const char * const *names, u32 namesmask){	char str[33]; 	audit_log_format(ab, "\"");	if ((mask & chrsmask) && chrs) {		aa_perm_mask_to_str(str, sizeof(str), chrs, mask & chrsmask);		mask &= ~chrsmask;		audit_log_format(ab, "%s", str);		if (mask & namesmask)			audit_log_format(ab, " ");	}	if ((mask & namesmask) && names)		aa_audit_perm_names(ab, names, mask & namesmask);	audit_log_format(ab, "\"");} /** * aa_apply_modes_to_perms - apply namespace and profile flags to perms * @profile: that perms where computed from * @perms: perms to apply mode modifiers to * * TODO: split into profile and ns based flags for when accumulating perms */void aa_apply_modes_to_perms(struct aa_profile *profile, struct aa_perms *perms){	switch (AUDIT_MODE(profile)) {	case AUDIT_ALL:		perms->audit = ALL_PERMS_MASK;		fallthrough;	case AUDIT_NOQUIET:		perms->quiet = 0;		break;	case AUDIT_QUIET:		perms->audit = 0;		fallthrough;	case AUDIT_QUIET_DENIED:		perms->quiet = ALL_PERMS_MASK;		break;	} 	if (KILL_MODE(profile))		perms->kill = ALL_PERMS_MASK;	else if (COMPLAIN_MODE(profile))		perms->complain = ALL_PERMS_MASK;	else if (USER_MODE(profile))		perms->prompt = ALL_PERMS_MASK;} void aa_profile_match_label(struct aa_profile *profile,			    struct aa_ruleset *rules,			    struct aa_label *label,			    int type, u32 request, struct aa_perms *perms){	/* TODO: doesn't yet handle extended types */	aa_state_t state; 	state = aa_dfa_next(rules->policy->dfa,			    rules->policy->start[AA_CLASS_LABEL],			    type);	aa_label_match(profile, rules, label, state, false, request, perms);}  /** * aa_check_perms - do audit mode selection based on perms set * @profile: profile being checked * @perms: perms computed for the request * @request: requested perms * @ad: initialized audit structure (MAY BE NULL if not auditing) * @cb: callback fn for type specific fields (MAY BE NULL) * * Returns: 0 if permission else error code * * Note: profile audit modes need to be set before calling by setting the *       perm masks appropriately. * *       If not auditing then complain mode is not enabled and the *       error code will indicate whether there was an explicit deny *	 with a positive value. */int aa_check_perms(struct aa_profile *profile, struct aa_perms *perms,		   u32 request, struct apparmor_audit_data *ad,		   void (*cb)(struct audit_buffer *, void *)){	int type, error;	u32 denied = request & (~perms->allow | perms->deny); 	if (likely(!denied)) {		/* mask off perms that are not being force audited */		request &= perms->audit;		if (!request || !ad)			return 0; 		type = AUDIT_APPARMOR_AUDIT;		error = 0;	} else {		error = -EACCES; 		if (denied & perms->kill)			type = AUDIT_APPARMOR_KILL;		else if (denied == (denied & perms->complain))			type = AUDIT_APPARMOR_ALLOWED;		else			type = AUDIT_APPARMOR_DENIED; 		if (denied == (denied & perms->hide))			error = -ENOENT; 		denied &= ~perms->quiet;		if (!ad || !denied)			return error;	} 	if (ad) {		ad->subj_label = &profile->label;		ad->request = request;		ad->denied = denied;		ad->error = error;		aa_audit_msg(type, ad, cb);	} 	if (type == AUDIT_APPARMOR_ALLOWED)		error = 0; 	return error;}  /** * aa_policy_init - initialize a policy structure * @policy: policy to initialize  (NOT NULL) * @prefix: prefix name if any is required.  (MAYBE NULL) * @name: name of the policy, init will make a copy of it  (NOT NULL) * @gfp: allocation mode * * Note: this fn creates a copy of strings passed in * * Returns: true if policy init successful */bool aa_policy_init(struct aa_policy *policy, const char *prefix,		    const char *name, gfp_t gfp){	char *hname; 	/* freed by policy_free */	if (prefix) {		hname = aa_str_alloc(strlen(prefix) + strlen(name) + 3, gfp);		if (hname)			sprintf(hname, "%s//%s", prefix, name);	} else {		hname = aa_str_alloc(strlen(name) + 1, gfp);		if (hname)			strcpy(hname, name);	}	if (!hname)		return false;	policy->hname = hname;	/* base.name is a substring of fqname */	policy->name = basename(policy->hname);	INIT_LIST_HEAD(&policy->list);	INIT_LIST_HEAD(&policy->profiles); 	return true;} /** * aa_policy_destroy - free the elements referenced by @policy * @policy: policy that is to have its elements freed  (NOT NULL) */void aa_policy_destroy(struct aa_policy *policy){	AA_BUG(on_list_rcu(&policy->profiles));	AA_BUG(on_list_rcu(&policy->list)); 	/* don't free name as its a subset of hname */	aa_put_str(policy->hname);}