197 lines
5.4 KiB
C
197 lines
5.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* AppArmor security module
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*
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* This file contains AppArmor policy dfa matching engine definitions.
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*
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* Copyright (C) 1998-2008 Novell/SUSE
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* Copyright 2009-2012 Canonical Ltd.
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*/
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#ifndef __AA_MATCH_H
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#define __AA_MATCH_H
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#include <linux/kref.h>
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#define DFA_NOMATCH 0
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#define DFA_START 1
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/**
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* The format used for transition tables is based on the GNU flex table
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* file format (--tables-file option; see Table File Format in the flex
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* info pages and the flex sources for documentation). The magic number
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* used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because
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* new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF
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* (default) tables are used slightly differently (see the apparmor-parser
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* package).
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*
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*
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* The data in the packed dfa is stored in network byte order, and the tables
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* are arranged for flexibility. We convert the table data to host native
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* byte order.
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*
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* The dfa begins with a table set header, and is followed by the actual
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* tables.
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*/
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#define YYTH_MAGIC 0x1B5E783D
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#define YYTH_FLAG_DIFF_ENCODE 1
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#define YYTH_FLAG_OOB_TRANS 2
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#define YYTH_FLAGS (YYTH_FLAG_DIFF_ENCODE | YYTH_FLAG_OOB_TRANS)
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#define MAX_OOB_SUPPORTED 1
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struct table_set_header {
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u32 th_magic; /* YYTH_MAGIC */
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u32 th_hsize;
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u32 th_ssize;
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u16 th_flags;
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char th_version[];
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};
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/* The YYTD_ID are one less than flex table mappings. The flex id
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* has 1 subtracted at table load time, this allows us to directly use the
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* ID's as indexes.
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*/
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#define YYTD_ID_ACCEPT 0
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#define YYTD_ID_BASE 1
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#define YYTD_ID_CHK 2
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#define YYTD_ID_DEF 3
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#define YYTD_ID_EC 4
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#define YYTD_ID_META 5
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#define YYTD_ID_ACCEPT2 6
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#define YYTD_ID_NXT 7
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#define YYTD_ID_TSIZE 8
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#define YYTD_ID_MAX 8
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#define YYTD_DATA8 1
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#define YYTD_DATA16 2
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#define YYTD_DATA32 4
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#define YYTD_DATA64 8
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/* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the
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* first flags
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*/
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#define ACCEPT1_FLAGS(X) ((X) & 0x3f)
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#define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2)
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#define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X)
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#define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2)
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#define DFA_FLAG_VERIFY_STATES 0x1000
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struct table_header {
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u16 td_id;
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u16 td_flags;
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u32 td_hilen;
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u32 td_lolen;
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char td_data[];
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};
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#define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data))
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#define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data))
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#define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data))
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#define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data))
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#define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data))
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#define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data))
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#define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data))
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struct aa_dfa {
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struct kref count;
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u16 flags;
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u32 max_oob;
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struct table_header *tables[YYTD_ID_TSIZE];
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};
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extern struct aa_dfa *nulldfa;
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extern struct aa_dfa *stacksplitdfa;
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#define byte_to_byte(X) (X)
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#define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX) \
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do { \
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typeof(LEN) __i; \
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TTYPE *__t = (TTYPE *) TABLE; \
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BTYPE *__b = (BTYPE *) BLOB; \
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for (__i = 0; __i < LEN; __i++) { \
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__t[__i] = NTOHX(__b[__i]); \
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} \
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} while (0)
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static inline size_t table_size(size_t len, size_t el_size)
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{
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return ALIGN(sizeof(struct table_header) + len * el_size, 8);
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}
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int aa_setup_dfa_engine(void);
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void aa_teardown_dfa_engine(void);
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struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);
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unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
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const char *str, int len);
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unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
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const char *str);
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unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
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const char c);
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unsigned int aa_dfa_outofband_transition(struct aa_dfa *dfa,
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unsigned int state);
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unsigned int aa_dfa_match_until(struct aa_dfa *dfa, unsigned int start,
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const char *str, const char **retpos);
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unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start,
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const char *str, int n, const char **retpos);
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void aa_dfa_free_kref(struct kref *kref);
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#define WB_HISTORY_SIZE 24
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struct match_workbuf {
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unsigned int count;
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unsigned int pos;
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unsigned int len;
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unsigned int size; /* power of 2, same as history size */
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unsigned int history[WB_HISTORY_SIZE];
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};
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#define DEFINE_MATCH_WB(N) \
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struct match_workbuf N = { \
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.count = 0, \
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.pos = 0, \
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.len = 0, \
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}
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unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start,
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const char *str, unsigned int *count);
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/**
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* aa_get_dfa - increment refcount on dfa @p
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* @dfa: dfa (MAYBE NULL)
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*
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* Returns: pointer to @dfa if @dfa is NULL will return NULL
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* Requires: @dfa must be held with valid refcount when called
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*/
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static inline struct aa_dfa *aa_get_dfa(struct aa_dfa *dfa)
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{
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if (dfa)
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kref_get(&(dfa->count));
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return dfa;
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}
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/**
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* aa_put_dfa - put a dfa refcount
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* @dfa: dfa to put refcount (MAYBE NULL)
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*
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* Requires: if @dfa != NULL that a valid refcount be held
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*/
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static inline void aa_put_dfa(struct aa_dfa *dfa)
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{
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if (dfa)
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kref_put(&dfa->count, aa_dfa_free_kref);
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}
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#define MATCH_FLAG_DIFF_ENCODE 0x80000000
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#define MARK_DIFF_ENCODE 0x40000000
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#define MATCH_FLAG_OOB_TRANSITION 0x20000000
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#define MATCH_FLAGS_MASK 0xff000000
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#define MATCH_FLAGS_VALID (MATCH_FLAG_DIFF_ENCODE | MATCH_FLAG_OOB_TRANSITION)
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#define MATCH_FLAGS_INVALID (MATCH_FLAGS_MASK & ~MATCH_FLAGS_VALID)
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#endif /* __AA_MATCH_H */
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