/* SPDX-License-Identifier: GPL-2.0-only */
/*
* AppArmor security module
*
* This file contains AppArmor lib definitions
*
* 2017 Canonical Ltd.
*/
#ifndef __AA_LIB_H
#define __AA_LIB_H
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/lsm_hooks.h>
#include "match.h"
/*
* DEBUG remains global (no per profile flag) since it is mostly used in sysctl
* which is not related to profile accesses.
*/
#define DEBUG_ON (aa_g_debug)
#define dbg_printk(__fmt, __args...) pr_debug(__fmt, ##__args)
#define AA_DEBUG(fmt, args...) \
do { \
if (DEBUG_ON) \
pr_debug_ratelimited("AppArmor: " fmt, ##args); \
} while (0)
#define AA_WARN(X) WARN((X), "APPARMOR WARN %s: %s\n", __func__, #X)
#define AA_BUG(X, args...) AA_BUG_FMT((X), "" args)
#ifdef CONFIG_SECURITY_APPARMOR_DEBUG_ASSERTS
#define AA_BUG_FMT(X, fmt, args...) \
WARN((X), "AppArmor WARN %s: (" #X "): " fmt, __func__, ##args)
#else
#define AA_BUG_FMT(X, fmt, args...)
#endif
#define AA_ERROR(fmt, args...) \
pr_err_ratelimited("AppArmor: " fmt, ##args)
/* Flag indicating whether initialization completed */
extern int apparmor_initialized;
/* fn's in lib */
const char *skipn_spaces(const char *str, size_t n);
char *aa_split_fqname(char *args, char **ns_name);
const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
size_t *ns_len);
void aa_info_message(const char *str);
/* Security blob offsets */
extern struct lsm_blob_sizes apparmor_blob_sizes;
/**
* aa_strneq - compare null terminated @str to a non null terminated substring
* @str: a null terminated string
* @sub: a substring, not necessarily null terminated
* @len: length of @sub to compare
*
* The @str string must be full consumed for this to be considered a match
*/
static inline bool aa_strneq(const char *str, const char *sub, int len)
{
return !strncmp(str, sub, len) && !str[len];
}
/**
* aa_dfa_null_transition - step to next state after null character
* @dfa: the dfa to match against
* @start: the state of the dfa to start matching in
*
* aa_dfa_null_transition transitions to the next state after a null
* character which is not used in standard matching and is only
* used to separate pairs.
*/
static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
unsigned int start)
{
/* the null transition only needs the string's null terminator byte */
return aa_dfa_next(dfa, start, 0);
}
static inline bool path_mediated_fs(struct dentry *dentry)
{
return !(dentry->d_sb->s_flags & SB_NOUSER);
}
struct counted_str {
struct kref count;
char name[];
};
#define str_to_counted(str) \
((struct counted_str *)(str - offsetof(struct counted_str, name)))
#define __counted /* atm just a notation */
void aa_str_kref(struct kref *kref);
char *aa_str_alloc(int size, gfp_t gfp);
static inline __counted char *aa_get_str(__counted char *str)
{
if (str)
kref_get(&(str_to_counted(str)->count));
return str;
}
static inline void aa_put_str(__counted char *str)
{
if (str)
kref_put(&str_to_counted(str)->count, aa_str_kref);
}
/* struct aa_policy - common part of both namespaces and profiles
* @name: name of the object
* @hname - The hierarchical name
* @list: list policy object is on
* @profiles: head of the profiles list contained in the object
*/
struct aa_policy {
const char *name;
__counted char *hname;
struct list_head list;
struct list_head profiles;
};
/**
* basename - find the last component of an hname
* @name: hname to find the base profile name component of (NOT NULL)
*
* Returns: the tail (base profile name) name component of an hname
*/
static inline const char *basename(const char *hname)
{
char *split;
hname = strim((char *)hname);
for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
hname = split + 2;
return hname;
}
/**
* __policy_find - find a policy by @name on a policy list
* @head: list to search (NOT NULL)
* @name: name to search for (NOT NULL)
*
* Requires: rcu_read_lock be held
*
* Returns: unrefcounted policy that match @name or NULL if not found
*/
static inline struct aa_policy *__policy_find(struct list_head *head,
const char *name)
{
struct aa_policy *policy;
list_for_each_entry_rcu(policy, head, list) {
if (!strcmp(policy->name, name))
return policy;
}
return NULL;
}
/**
* __policy_strn_find - find a policy that's name matches @len chars of @str
* @head: list to search (NOT NULL)
* @str: string to search for (NOT NULL)
* @len: length of match required
*
* Requires: rcu_read_lock be held
*
* Returns: unrefcounted policy that match @str or NULL if not found
*
* if @len == strlen(@strlen) then this is equiv to __policy_find
* other wise it allows searching for policy by a partial match of name
*/
static inline struct aa_policy *__policy_strn_find(struct list_head *head,
const char *str, int len)
{
struct aa_policy *policy;
list_for_each_entry_rcu(policy, head, list) {
if (aa_strneq(policy->name, str, len))
return policy;
}
return NULL;
}
bool aa_policy_init(struct aa_policy *policy, const char *prefix,
const char *name, gfp_t gfp);
void aa_policy_destroy(struct aa_policy *policy);
/*
* fn_label_build - abstract out the build of a label transition
* @L: label the transition is being computed for
* @P: profile parameter derived from L by this macro, can be passed to FN
* @GFP: memory allocation type to use
* @FN: fn to call for each profile transition. @P is set to the profile
*
* Returns: new label on success
* ERR_PTR if build @FN fails
* NULL if label_build fails due to low memory conditions
*
* @FN must return a label or ERR_PTR on failure. NULL is not allowed
*/
#define fn_label_build(L, P, GFP, FN) \
({ \
__label__ __cleanup, __done; \
struct aa_label *__new_; \
\
if ((L)->size > 1) { \
/* TODO: add cache of transitions already done */ \
struct label_it __i; \
int __j, __k, __count; \
DEFINE_VEC(label, __lvec); \
DEFINE_VEC(profile, __pvec); \
if (vec_setup(label, __lvec, (L)->size, (GFP))) { \
__new_ = NULL; \
goto __done; \
} \
__j = 0; \
label_for_each(__i, (L), (P)) { \
__new_ = (FN); \
AA_BUG(!__new_); \
if (IS_ERR(__new_)) \
goto __cleanup; \
__lvec[__j++] = __new_; \
} \
for (__j = __count = 0; __j < (L)->size; __j++) \
__count += __lvec[__j]->size; \
if (!vec_setup(profile, __pvec, __count, (GFP))) { \
for (__j = __k = 0; __j < (L)->size; __j++) { \
label_for_each(__i, __lvec[__j], (P)) \
__pvec[__k++] = aa_get_profile(P); \
} \
__count -= aa_vec_unique(__pvec, __count, 0); \
if (__count > 1) { \
__new_ = aa_vec_find_or_create_label(__pvec,\
__count, (GFP)); \
/* only fails if out of Mem */ \
if (!__new_) \
__new_ = NULL; \
} else \
__new_ = aa_get_label(&__pvec[0]->label); \
vec_cleanup(profile, __pvec, __count); \
} else \
__new_ = NULL; \
__cleanup: \
vec_cleanup(label, __lvec, (L)->size); \
} else { \
(P) = labels_profile(L); \
__new_ = (FN); \
} \
__done: \
if (!__new_) \
AA_DEBUG("label build failed\n"); \
(__new_); \
})
#define __fn_build_in_ns(NS, P, NS_FN, OTHER_FN) \
({ \
struct aa_label *__new; \
if ((P)->ns != (NS)) \
__new = (OTHER_FN); \
else \
__new = (NS_FN); \
(__new); \
})
#define fn_label_build_in_ns(L, P, GFP, NS_FN, OTHER_FN) \
({ \
fn_label_build((L), (P), (GFP), \
__fn_build_in_ns(labels_ns(L), (P), (NS_FN), (OTHER_FN))); \
})
#endif /* __AA_LIB_H */
