// SPDX-License-Identifier: GPL-2.0-only /* * AppArmor security module * * This file contains AppArmor label definitions * * Copyright 2017 Canonical Ltd. */ #include <linux/audit.h> #include <linux/seq_file.h> #include <linux/sort.h> #include "include/apparmor.h" #include "include/cred.h" #include "include/label.h" #include "include/policy.h" #include "include/secid.h" /* * the aa_label represents the set of profiles confining an object * * Labels maintain a reference count to the set of pointers they reference * Labels are ref counted by * tasks and object via the security field/security context off the field * code - will take a ref count on a label if it needs the label * beyond what is possible with an rcu_read_lock. * profiles - each profile is a label * secids - a pinned secid will keep a refcount of the label it is * referencing * objects - inode, files, sockets, ... * * Labels are not ref counted by the label set, so they maybe removed and * freed when no longer in use. * */ #define PROXY_POISON … #define LABEL_POISON … static void free_proxy(struct aa_proxy *proxy) { … } void aa_proxy_kref(struct kref *kref) { … } struct aa_proxy *aa_alloc_proxy(struct aa_label *label, gfp_t gfp) { … } /* requires profile list write lock held */ void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new) { … } static void __proxy_share(struct aa_label *old, struct aa_label *new) { … } /** * ns_cmp - compare ns for label set ordering * @a: ns to compare (NOT NULL) * @b: ns to compare (NOT NULL) * * Returns: <0 if a < b * ==0 if a == b * >0 if a > b */ static int ns_cmp(struct aa_ns *a, struct aa_ns *b) { … } /** * profile_cmp - profile comparison for set ordering * @a: profile to compare (NOT NULL) * @b: profile to compare (NOT NULL) * * Returns: <0 if a < b * ==0 if a == b * >0 if a > b */ static int profile_cmp(struct aa_profile *a, struct aa_profile *b) { … } /** * vec_cmp - label comparison for set ordering * @a: aa_profile to compare (NOT NULL) * @an: length of @a * @b: aa_profile to compare (NOT NULL) * @bn: length of @b * * Returns: <0 if @a < @b * ==0 if @a == @b * >0 if @a > @b */ static int vec_cmp(struct aa_profile **a, int an, struct aa_profile **b, int bn) { … } static bool vec_is_stale(struct aa_profile **vec, int n) { … } static long accum_vec_flags(struct aa_profile **vec, int n) { … } static int sort_cmp(const void *a, const void *b) { … } /* * assumes vec is sorted * Assumes @vec has null terminator at vec[n], and will null terminate * vec[n - dups] */ static inline int unique(struct aa_profile **vec, int n) { … } /** * aa_vec_unique - canonical sort and unique a list of profiles * @n: number of refcounted profiles in the list (@n > 0) * @vec: list of profiles to sort and merge * @flags: null terminator flags of @vec * * Returns: the number of duplicates eliminated == references put * * If @flags & VEC_FLAG_TERMINATE @vec has null terminator at vec[n], and will * null terminate vec[n - dups] */ int aa_vec_unique(struct aa_profile **vec, int n, int flags) { … } void aa_label_destroy(struct aa_label *label) { … } void aa_label_free(struct aa_label *label) { … } static void label_free_switch(struct aa_label *label) { … } static void label_free_rcu(struct rcu_head *head) { … } void aa_label_kref(struct kref *kref) { … } static void label_free_or_put_new(struct aa_label *label, struct aa_label *new) { … } bool aa_label_init(struct aa_label *label, int size, gfp_t gfp) { … } /** * aa_label_alloc - allocate a label with a profile vector of @size length * @size: size of profile vector in the label * @proxy: proxy to use OR null if to allocate a new one * @gfp: memory allocation type * * Returns: new label * else NULL if failed */ struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp) { … } /** * label_cmp - label comparison for set ordering * @a: label to compare (NOT NULL) * @b: label to compare (NOT NULL) * * Returns: <0 if a < b * ==0 if a == b * >0 if a > b */ static int label_cmp(struct aa_label *a, struct aa_label *b) { … } /* helper fn for label_for_each_confined */ int aa_label_next_confined(struct aa_label *label, int i) { … } /** * __aa_label_next_not_in_set - return the next profile of @sub not in @set * @I: label iterator * @set: label to test against * @sub: label to if is subset of @set * * Returns: profile in @sub that is not in @set, with iterator set pos after * else NULL if @sub is a subset of @set */ struct aa_profile *__aa_label_next_not_in_set(struct label_it *I, struct aa_label *set, struct aa_label *sub) { … } /** * aa_label_is_subset - test if @sub is a subset of @set * @set: label to test against * @sub: label to test if is subset of @set * * Returns: true if @sub is subset of @set * else false */ bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub) { … } /** * aa_label_is_unconfined_subset - test if @sub is a subset of @set * @set: label to test against * @sub: label to test if is subset of @set * * This checks for subset but taking into account unconfined. IF * @sub contains an unconfined profile that does not have a matching * unconfined in @set then this will not cause the test to fail. * Conversely we don't care about an unconfined in @set that is not in * @sub * * Returns: true if @sub is special_subset of @set * else false */ bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub) { … } /** * __label_remove - remove @label from the label set * @label: label to remove * @new: label to redirect to * * Requires: labels_set(@label)->lock write_lock * Returns: true if the label was in the tree and removed */ static bool __label_remove(struct aa_label *label, struct aa_label *new) { … } /** * __label_replace - replace @old with @new in label set * @old: label to remove from label set * @new: label to replace @old with * * Requires: labels_set(@old)->lock write_lock * valid ref count be held on @new * Returns: true if @old was in set and replaced by @new * * Note: current implementation requires label set be order in such a way * that @new directly replaces @old position in the set (ie. * using pointer comparison of the label address would not work) */ static bool __label_replace(struct aa_label *old, struct aa_label *new) { … } /** * __label_insert - attempt to insert @l into a label set * @ls: set of labels to insert @l into (NOT NULL) * @label: new label to insert (NOT NULL) * @replace: whether insertion should replace existing entry that is not stale * * Requires: @ls->lock * caller to hold a valid ref on l * if @replace is true l has a preallocated proxy associated * Returns: @l if successful in inserting @l - with additional refcount * else ref counted equivalent label that is already in the set, * the else condition only happens if @replace is false */ static struct aa_label *__label_insert(struct aa_labelset *ls, struct aa_label *label, bool replace) { … } /** * __vec_find - find label that matches @vec in label set * @vec: vec of profiles to find matching label for (NOT NULL) * @n: length of @vec * * Requires: @vec_labelset(vec) lock held * caller to hold a valid ref on l * * Returns: ref counted @label if matching label is in tree * ref counted label that is equiv to @l in tree * else NULL if @vec equiv is not in tree */ static struct aa_label *__vec_find(struct aa_profile **vec, int n) { … } /** * __label_find - find label @label in label set * @label: label to find (NOT NULL) * * Requires: labels_set(@label)->lock held * caller to hold a valid ref on l * * Returns: ref counted @label if @label is in tree OR * ref counted label that is equiv to @label in tree * else NULL if @label or equiv is not in tree */ static struct aa_label *__label_find(struct aa_label *label) { … } /** * aa_label_remove - remove a label from the labelset * @label: label to remove * * Returns: true if @label was removed from the tree * else @label was not in tree so it could not be removed */ bool aa_label_remove(struct aa_label *label) { … } /** * aa_label_replace - replace a label @old with a new version @new * @old: label to replace * @new: label replacing @old * * Returns: true if @old was in tree and replaced * else @old was not in tree, and @new was not inserted */ bool aa_label_replace(struct aa_label *old, struct aa_label *new) { … } /** * vec_find - find label @l in label set * @vec: array of profiles to find equiv label for (NOT NULL) * @n: length of @vec * * Returns: refcounted label if @vec equiv is in tree * else NULL if @vec equiv is not in tree */ static struct aa_label *vec_find(struct aa_profile **vec, int n) { … } /* requires sort and merge done first */ static struct aa_label *vec_create_and_insert_label(struct aa_profile **vec, int len, gfp_t gfp) { … } struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len, gfp_t gfp) { … } /** * aa_label_find - find label @label in label set * @label: label to find (NOT NULL) * * Requires: caller to hold a valid ref on l * * Returns: refcounted @label if @label is in tree * refcounted label that is equiv to @label in tree * else NULL if @label or equiv is not in tree */ struct aa_label *aa_label_find(struct aa_label *label) { … } /** * aa_label_insert - insert label @label into @ls or return existing label * @ls: labelset to insert @label into * @label: label to insert * * Requires: caller to hold a valid ref on @label * * Returns: ref counted @label if successful in inserting @label * else ref counted equivalent label that is already in the set */ struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *label) { … } /** * aa_label_next_in_merge - find the next profile when merging @a and @b * @I: label iterator * @a: label to merge * @b: label to merge * * Returns: next profile * else null if no more profiles */ struct aa_profile *aa_label_next_in_merge(struct label_it *I, struct aa_label *a, struct aa_label *b) { … } /** * label_merge_cmp - cmp of @a merging with @b against @z for set ordering * @a: label to merge then compare (NOT NULL) * @b: label to merge then compare (NOT NULL) * @z: label to compare merge against (NOT NULL) * * Assumes: using the most recent versions of @a, @b, and @z * * Returns: <0 if a < b * ==0 if a == b * >0 if a > b */ static int label_merge_cmp(struct aa_label *a, struct aa_label *b, struct aa_label *z) { … } /** * label_merge_insert - create a new label by merging @a and @b * @new: preallocated label to merge into (NOT NULL) * @a: label to merge with @b (NOT NULL) * @b: label to merge with @a (NOT NULL) * * Requires: preallocated proxy * * Returns: ref counted label either @new if merge is unique * @a if @b is a subset of @a * @b if @a is a subset of @b * * NOTE: will not use @new if the merge results in @new == @a or @b * * Must be used within labelset write lock to avoid racing with * setting labels stale. */ static struct aa_label *label_merge_insert(struct aa_label *new, struct aa_label *a, struct aa_label *b) { … } /** * labelset_of_merge - find which labelset a merged label should be inserted * @a: label to merge and insert * @b: label to merge and insert * * Returns: labelset that the merged label should be inserted into */ static struct aa_labelset *labelset_of_merge(struct aa_label *a, struct aa_label *b) { … } /** * __label_find_merge - find label that is equiv to merge of @a and @b * @ls: set of labels to search (NOT NULL) * @a: label to merge with @b (NOT NULL) * @b: label to merge with @a (NOT NULL) * * Requires: ls->lock read_lock held * * Returns: ref counted label that is equiv to merge of @a and @b * else NULL if merge of @a and @b is not in set */ static struct aa_label *__label_find_merge(struct aa_labelset *ls, struct aa_label *a, struct aa_label *b) { … } /** * aa_label_find_merge - find label that is equiv to merge of @a and @b * @a: label to merge with @b (NOT NULL) * @b: label to merge with @a (NOT NULL) * * Requires: labels be fully constructed with a valid ns * * Returns: ref counted label that is equiv to merge of @a and @b * else NULL if merge of @a and @b is not in set */ struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b) { … } /** * aa_label_merge - attempt to insert new merged label of @a and @b * @a: label to merge with @b (NOT NULL) * @b: label to merge with @a (NOT NULL) * @gfp: memory allocation type * * Requires: caller to hold valid refs on @a and @b * labels be fully constructed with a valid ns * * Returns: ref counted new label if successful in inserting merge of a & b * else ref counted equivalent label that is already in the set. * else NULL if could not create label (-ENOMEM) */ struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b, gfp_t gfp) { … } /* match a profile and its associated ns component if needed * Assumes visibility test has already been done. * If a subns profile is not to be matched should be prescreened with * visibility test. */ static inline aa_state_t match_component(struct aa_profile *profile, struct aa_ruleset *rules, struct aa_profile *tp, aa_state_t state) { … } /** * label_compound_match - find perms for full compound label * @profile: profile to find perms for * @rules: ruleset to search * @label: label to check access permissions for * @state: state to start match in * @subns: whether to do permission checks on components in a subns * @request: permissions to request * @perms: perms struct to set * * Returns: 0 on success else ERROR * * For the label A//&B//&C this does the perm match for A//&B//&C * @perms should be preinitialized with allperms OR a previous permission * check to be stacked. */ static int label_compound_match(struct aa_profile *profile, struct aa_ruleset *rules, struct aa_label *label, aa_state_t state, bool subns, u32 request, struct aa_perms *perms) { … } /** * label_components_match - find perms for all subcomponents of a label * @profile: profile to find perms for * @rules: ruleset to search * @label: label to check access permissions for * @start: state to start match in * @subns: whether to do permission checks on components in a subns * @request: permissions to request * @perms: an initialized perms struct to add accumulation to * * Returns: 0 on success else ERROR * * For the label A//&B//&C this does the perm match for each of A and B and C * @perms should be preinitialized with allperms OR a previous permission * check to be stacked. */ static int label_components_match(struct aa_profile *profile, struct aa_ruleset *rules, struct aa_label *label, aa_state_t start, bool subns, u32 request, struct aa_perms *perms) { … } /** * aa_label_match - do a multi-component label match * @profile: profile to match against (NOT NULL) * @rules: ruleset to search * @label: label to match (NOT NULL) * @state: state to start in * @subns: whether to match subns components * @request: permission request * @perms: Returns computed perms (NOT NULL) * * Returns: the state the match finished in, may be the none matching state */ int aa_label_match(struct aa_profile *profile, struct aa_ruleset *rules, struct aa_label *label, aa_state_t state, bool subns, u32 request, struct aa_perms *perms) { … } /** * aa_update_label_name - update a label to have a stored name * @ns: ns being viewed from (NOT NULL) * @label: label to update (NOT NULL) * @gfp: type of memory allocation * * Requires: labels_set(label) not locked in caller * * note: only updates the label name if it does not have a name already * and if it is in the labelset */ bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp) { … } /* * cached label name is present and visible * @label->hname only exists if label is namespace hierachical */ static inline bool use_label_hname(struct aa_ns *ns, struct aa_label *label, int flags) { … } /* helper macro for snprint routines */ #define update_for_len … /** * aa_profile_snxprint - print a profile name to a buffer * @str: buffer to write to. (MAY BE NULL if @size == 0) * @size: size of buffer * @view: namespace profile is being viewed from * @profile: profile to view (NOT NULL) * @flags: whether to include the mode string * @prev_ns: last ns printed when used in compound print * * Returns: size of name written or would be written if larger than * available buffer * * Note: will not print anything if the profile is not visible */ static int aa_profile_snxprint(char *str, size_t size, struct aa_ns *view, struct aa_profile *profile, int flags, struct aa_ns **prev_ns) { … } static const char *label_modename(struct aa_ns *ns, struct aa_label *label, int flags) { … } /* if any visible label is not unconfined the display_mode returns true */ static inline bool display_mode(struct aa_ns *ns, struct aa_label *label, int flags) { … } /** * aa_label_snxprint - print a label name to a string buffer * @str: buffer to write to. (MAY BE NULL if @size == 0) * @size: size of buffer * @ns: namespace profile is being viewed from * @label: label to view (NOT NULL) * @flags: whether to include the mode string * * Returns: size of name written or would be written if larger than * available buffer * * Note: labels do not have to be strictly hierarchical to the ns as * objects may be shared across different namespaces and thus * pickup labeling from each ns. If a particular part of the * label is not visible it will just be excluded. And if none * of the label is visible "---" will be used. */ int aa_label_snxprint(char *str, size_t size, struct aa_ns *ns, struct aa_label *label, int flags) { … } #undef update_for_len /** * aa_label_asxprint - allocate a string buffer and print label into it * @strp: Returns - the allocated buffer with the label name. (NOT NULL) * @ns: namespace profile is being viewed from * @label: label to view (NOT NULL) * @flags: flags controlling what label info is printed * @gfp: kernel memory allocation type * * Returns: size of name written or would be written if larger than * available buffer */ int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label, int flags, gfp_t gfp) { … } /** * aa_label_acntsxprint - allocate a __counted string buffer and print label * @strp: buffer to write to. * @ns: namespace profile is being viewed from * @label: label to view (NOT NULL) * @flags: flags controlling what label info is printed * @gfp: kernel memory allocation type * * Returns: size of name written or would be written if larger than * available buffer */ int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns, struct aa_label *label, int flags, gfp_t gfp) { … } void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns, struct aa_label *label, int flags, gfp_t gfp) { … } void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns, struct aa_label *label, int flags, gfp_t gfp) { … } void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags, gfp_t gfp) { … } void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp) { … } void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp) { … } void aa_label_printk(struct aa_label *label, gfp_t gfp) { … } static int label_count_strn_entries(const char *str, size_t n) { … } /* * ensure stacks with components like * :ns:A//&B * have :ns: applied to both 'A' and 'B' by making the lookup relative * to the base if the lookup specifies an ns, else making the stacked lookup * relative to the last embedded ns in the string. */ static struct aa_profile *fqlookupn_profile(struct aa_label *base, struct aa_label *currentbase, const char *str, size_t n) { … } /** * aa_label_strn_parse - parse, validate and convert a text string to a label * @base: base label to use for lookups (NOT NULL) * @str: null terminated text string (NOT NULL) * @n: length of str to parse, will stop at \0 if encountered before n * @gfp: allocation type * @create: true if should create compound labels if they don't exist * @force_stack: true if should stack even if no leading & * * Returns: the matching refcounted label if present * else ERRPTR */ struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str, size_t n, gfp_t gfp, bool create, bool force_stack) { … } struct aa_label *aa_label_parse(struct aa_label *base, const char *str, gfp_t gfp, bool create, bool force_stack) { … } /** * aa_labelset_destroy - remove all labels from the label set * @ls: label set to cleanup (NOT NULL) * * Labels that are removed from the set may still exist beyond the set * being destroyed depending on their reference counting */ void aa_labelset_destroy(struct aa_labelset *ls) { … } /* * @ls: labelset to init (NOT NULL) */ void aa_labelset_init(struct aa_labelset *ls) { … } static struct aa_label *labelset_next_stale(struct aa_labelset *ls) { … } /** * __label_update - insert updated version of @label into labelset * @label: the label to update/replace * * Returns: new label that is up to date * else NULL on failure * * Requires: @ns lock be held * * Note: worst case is the stale @label does not get updated and has * to be updated at a later time. */ static struct aa_label *__label_update(struct aa_label *label) { … } /** * __labelset_update - update labels in @ns * @ns: namespace to update labels in (NOT NULL) * * Requires: @ns lock be held * * Walk the labelset ensuring that all labels are up to date and valid * Any label that has a stale component is marked stale and replaced and * by an updated version. * * If failures happen due to memory pressures then stale labels will * be left in place until the next pass. */ static void __labelset_update(struct aa_ns *ns) { … } /** * __aa_labelset_update_subtree - update all labels with a stale component * @ns: ns to start update at (NOT NULL) * * Requires: @ns lock be held * * Invalidates labels based on @p in @ns and any children namespaces. */ void __aa_labelset_update_subtree(struct aa_ns *ns) { … }
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