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verified_exec.h revision 1.27
      1 /*	$NetBSD: verified_exec.h,v 1.27 2005/12/12 16:26:34 elad Exp $	*/
      2 
      3 /*-
      4  * Copyright 2005 Elad Efrat <elad (at) bsd.org.il>
      5  * Copyright 2005 Brett Lymn <blymn (at) netbsd.org>
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Brett Lymn and Elad Efrat
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Neither the name of The NetBSD Foundation nor the names of its
     16  *    contributors may be used to endorse or promote products derived
     17  *    from this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _SYS_VERIFIED_EXEC_H_
     33 #define _SYS_VERIFIED_EXEC_H_
     34 
     35 #include <sys/cdefs.h>
     36 #include <sys/param.h>
     37 #include <sys/hash.h>
     38 #include <uvm/uvm_extern.h>
     39 #include <uvm/uvm_pglist.h>
     40 #include <uvm/uvm_page.h>
     41 
     42 /* Max length of the fingerprint type string, including terminating \0 char */
     43 #define	VERIEXEC_TYPE_MAXLEN	9
     44 
     45 struct veriexec_params  {
     46 	unsigned char type;
     47 	unsigned char fp_type[VERIEXEC_TYPE_MAXLEN];
     48 	char file[MAXPATHLEN];
     49 	unsigned int size;  /* number of bytes in the fingerprint */
     50 	unsigned char *fingerprint;
     51 };
     52 
     53 struct veriexec_sizing_params {
     54 	dev_t dev;
     55 	size_t hash_size;
     56 };
     57 
     58 struct veriexec_delete_params {
     59 	dev_t dev;
     60 	ino_t ino;
     61 };
     62 
     63 /* Flags for a Veriexec entry. These can be OR'd together. */
     64 #define VERIEXEC_DIRECT		0x01 /* Direct execution (exec) */
     65 #define VERIEXEC_INDIRECT	0x02 /* Indirect execution (#!) */
     66 #define VERIEXEC_FILE		0x04 /* Plain file (open) */
     67 #define	VERIEXEC_UNTRUSTED	0x10 /* Untrusted storage */
     68 
     69 /* Operations for /dev/veriexec. */
     70 #define VERIEXEC_LOAD		_IOW('S', 0x1, struct veriexec_params)
     71 #define VERIEXEC_TABLESIZE	_IOW('S', 0x2, struct veriexec_sizing_params)
     72 #define VERIEXEC_DELETE		_IOW('S', 0x3, struct veriexec_delete_params)
     73 
     74 /* Verified exec sysctl objects. */
     75 #define	VERIEXEC_VERBOSE	1 /* Verbosity level. */
     76 #define	VERIEXEC_STRICT		2 /* Strict mode level. */
     77 #define	VERIEXEC_ALGORITHMS	3 /* Supported hashing algorithms. */
     78 #define	VERIEXEC_COUNT		4 /* # of fingerprinted files on device. */
     79 
     80 #ifdef _KERNEL
     81 void	veriexecattach(struct device *, struct device *, void *);
     82 int     veriexecopen(dev_t, int, int, struct lwp *);
     83 int     veriexecclose(dev_t, int, int, struct lwp *);
     84 int     veriexecioctl(dev_t, u_long, caddr_t, int, struct lwp *);
     85 
     86 /* defined in kern_verifiedexec.c */
     87 extern char *veriexec_fp_names;
     88 extern int veriexec_verbose;
     89 extern int veriexec_strict;
     90 /* this one requires sysctl.h to be included before verified_exec.h */
     91 #ifdef VERIEXEC_NEED_NODE
     92 extern const struct sysctlnode *veriexec_count_node;
     93 #endif /* VERIEXEC_NEED_NODE */
     94 
     95 /*
     96  * Operations vector for verified exec, this defines the characteristics
     97  * for the fingerprint type.
     98  * Function types: init, update, final.
     99  */
    100 typedef void (*VERIEXEC_INIT_FN)(void *);
    101 typedef void (*VERIEXEC_UPDATE_FN)(void *, u_char *, u_int);
    102 typedef void (*VERIEXEC_FINAL_FN)(u_char *, void *);
    103 
    104 struct veriexec_fp_ops {
    105 	char type[VERIEXEC_TYPE_MAXLEN];
    106 	size_t hash_len;
    107 	size_t context_size;
    108 	VERIEXEC_INIT_FN init;
    109 	VERIEXEC_UPDATE_FN update;
    110 	VERIEXEC_FINAL_FN final;
    111 	LIST_ENTRY(veriexec_fp_ops) entries;
    112 };
    113 
    114 /* An entry in the per-device hash table. */
    115 struct veriexec_hash_entry {
    116 	ino_t inode;				    /* Inode number. */
    117 	unsigned char type;			    /* Entry type. */
    118 	unsigned char status;			    /* Evaluation status. */
    119 	unsigned char page_fp_status;		    /* Per-page FP status. */
    120 	unsigned char *fp;			    /* Fingerprint. */
    121 	void *page_fp;				    /* Per-page fingerprints */
    122 	size_t npages;			    	    /* Number of pages. */
    123 	size_t last_page_size;			    /* To support < PAGE_SIZE */
    124 	struct veriexec_fp_ops *ops;		    /* Fingerprint ops vector*/
    125 	LIST_ENTRY(veriexec_hash_entry) entries;    /* List pointer. */
    126 };
    127 
    128 /* Valid status field values. */
    129 #define FINGERPRINT_NOTEVAL  0  /* fingerprint has not been evaluated */
    130 #define FINGERPRINT_VALID    1  /* fingerprint evaluated and matches list */
    131 #define FINGERPRINT_NOMATCH  2  /* fingerprint evaluated but does not match */
    132 
    133 /* Per-page fingerprint status. */
    134 #define	PAGE_FP_NONE	0	/* no per-page fingerprints. */
    135 #define	PAGE_FP_READY	1	/* per-page fingerprints ready for use. */
    136 #define	PAGE_FP_FAIL	2	/* mismatch in per-page fingerprints. */
    137 
    138 LIST_HEAD(veriexec_hashhead, veriexec_hash_entry);
    139 
    140 /* Veriexec hash table information. */
    141 struct veriexec_hashtbl {
    142 	struct veriexec_hashhead *hash_tbl;
    143 	size_t hash_size;	/* Number of slots in the table. */
    144 	dev_t hash_dev;		/* Device ID the hash table refers to. */
    145 	uint64_t hash_count;	/* # of fingerprinted files in table. */
    146 	LIST_ENTRY(veriexec_hashtbl) hash_list;
    147 };
    148 
    149 /* Global list of hash tables, one per device. */
    150 LIST_HEAD(, veriexec_hashtbl) veriexec_tables;
    151 
    152 /* Mask to ensure bounded access to elements in the hash table. */
    153 #define VERIEXEC_HASH_MASK(tbl)		((tbl)->hash_size - 1)
    154 
    155 /* Readable values for veriexec_report(). */
    156 #define	REPORT_NOVERBOSE	0	/* Always print */
    157 #define	REPORT_VERBOSE		1	/* Print when verbose >= 1 */
    158 #define	REPORT_VERBOSE_HIGH	2	/* Print when verbose >= 2 (debug) */
    159 #define	REPORT_NOPANIC		0	/* Normal report */
    160 #define	REPORT_PANIC		1	/* Use panic() */
    161 #define	REPORT_NOALARM		0	/* Normal report */
    162 #define	REPORT_ALARM		1	/* Alarm - also print pid/uid/.. */
    163 
    164 /*
    165  * Hashing function: Takes an inode number modulus the mask to give back
    166  * an index into the hash table.
    167  */
    168 #define VERIEXEC_HASH(tbl, inode)	\
    169 	(hash32_buf(&(inode), sizeof((inode)), HASH32_BUF_INIT) \
    170 	 & VERIEXEC_HASH_MASK(tbl))
    171 
    172 /* Initialize a fingerprint ops struct. */
    173 #define	VERIEXEC_OPINIT(ops, fp_type, hashlen, ctx_size, init_fn, \
    174 	update_fn, final_fn) \
    175 	do {								    \
    176 		(void) strlcpy((ops)->type, fp_type, sizeof((ops)->type));  \
    177 		(ops)->hash_len = (hashlen);				    \
    178 		(ops)->context_size = (ctx_size);			    \
    179 		(ops)->init = (VERIEXEC_INIT_FN) (init_fn);		    \
    180 		(ops)->update = (VERIEXEC_UPDATE_FN) (update_fn);	    \
    181 		(ops)->final = (VERIEXEC_FINAL_FN) (final_fn);		    \
    182 	} while (0);
    183 
    184 int veriexec_add_fp_ops(struct veriexec_fp_ops *);
    185 void veriexec_init_fp_ops(void);
    186 struct veriexec_fp_ops *veriexec_find_ops(u_char *name);
    187 int veriexec_fp_calc(struct lwp *, struct vnode *,
    188 		     struct veriexec_hash_entry *, uint64_t, u_char *);
    189 int veriexec_fp_cmp(struct veriexec_fp_ops *, u_char *, u_char *);
    190 struct veriexec_hashtbl *veriexec_tblfind(dev_t);
    191 struct veriexec_hash_entry *veriexec_lookup(dev_t, ino_t);
    192 int veriexec_hashadd(struct veriexec_hashtbl *, struct veriexec_hash_entry *);
    193 int veriexec_verify(struct lwp *, struct vnode *, struct vattr *,
    194 		    const u_char *, int, struct veriexec_hash_entry **);
    195 int veriexec_page_verify(struct veriexec_hash_entry *, struct vattr *,
    196 			 struct vm_page *, size_t, struct lwp *);
    197 int veriexec_removechk(struct lwp *, struct vnode *, const char *);
    198 int veriexec_renamechk(struct vnode *, const char *, const char *,
    199 		       struct lwp *);
    200 void veriexec_init_fp_ops(void);
    201 void veriexec_report(const u_char *, const u_char *, struct vattr *,
    202 		     struct lwp *, int, int, int);
    203 int veriexec_newtable(struct veriexec_sizing_params *);
    204 int veriexec_load(struct veriexec_params *, struct lwp *);
    205 int veriexec_delete(struct veriexec_delete_params *);
    206 
    207 #endif /* _KERNEL */
    208 
    209 #endif /* !_SYS_VERIFIED_EXEC_H_ */
    210