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/*
* AppArmor security module
*
* This file contains AppArmor functions for unpacking policy loaded from
* userspace.
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
* AppArmor uses a serialized binary format for loading policy. To find
* policy format documentation look in Documentation/security/apparmor.txt
* All policy is validated before it is used.
*/
#include <asm/unaligned.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include "include/apparmor.h"
#include "include/audit.h"
#include "include/context.h"
#include "include/crypto.h"
#include "include/match.h"
#include "include/policy.h"
#include "include/policy_unpack.h"
/*
* The AppArmor interface treats data as a type byte followed by the
* actual data. The interface has the notion of a a named entry
* which has a name (AA_NAME typecode followed by name string) followed by
* the entries typecode and data. Named types allow for optional
* elements and extensions to be added and tested for without breaking
* backwards compatibility.
*/
enum aa_code {
AA_U8,
AA_U16,
AA_U32,
AA_U64,
AA_NAME, /* same as string except it is items name */
AA_STRING,
AA_BLOB,
AA_STRUCT,
AA_STRUCTEND,
AA_LIST,
AA_LISTEND,
AA_ARRAY,
AA_ARRAYEND,
};
/*
* aa_ext is the read of the buffer containing the serialized profile. The
* data is copied into a kernel buffer in apparmorfs and then handed off to
* the unpack routines.
*/
struct aa_ext {
void *start;
void *end;
void *pos; /* pointer to current position in the buffer */
u32 version;
};
/* audit callback for unpack fields */
static void audit_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
if (sa->aad->iface.target) {
struct aa_profile *name = sa->aad->iface.target;
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab, name->base.hname);
}
if (sa->aad->iface.pos)
audit_log_format(ab, " offset=%ld", sa->aad->iface.pos);
}
/**
* audit_iface - do audit message for policy unpacking/load/replace/remove
* @new: profile if it has been allocated (MAYBE NULL)
* @name: name of the profile being manipulated (MAYBE NULL)
* @info: any extra info about the failure (MAYBE NULL)
* @e: buffer position info
* @error: error code
*
* Returns: %0 or error
*/
static int audit_iface(struct aa_profile *new, const char *name,
const char *info, struct aa_ext *e, int error)
{
struct aa_profile *profile = __aa_current_profile();
struct common_audit_data sa;
struct apparmor_audit_data aad = {0,};
sa.type = LSM_AUDIT_DATA_NONE;
sa.aad = &aad;
if (e)
aad.iface.pos = e->pos - e->start;
aad.iface.target = new;
aad.name = name;
aad.info = info;
aad.error = error;
return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
audit_cb);
}
/* test if read will be in packed data bounds */
static bool inbounds(struct aa_ext *e, size_t size)
{
return (size <= e->end - e->pos);
}
/**
* aa_u16_chunck - test and do bounds checking for a u16 size based chunk
* @e: serialized data read head (NOT NULL)
* @chunk: start address for chunk of data (NOT NULL)
*
* Returns: the size of chunk found with the read head at the end of the chunk.
*/
static size_t unpack_u16_chunk(struct aa_ext *e, char **chunk)
{
size_t size = 0;
if (!inbounds(e, sizeof(u16)))
return 0;
size = le16_to_cpu(get_unaligned((u16 *) e->pos));
e->pos += sizeof(u16);
if (!inbounds(e, size))
return 0;
*chunk = e->pos;
e->pos += size;
return size;
}
/* unpack control byte */
static bool unpack_X(struct aa_ext *e, enum aa_code code)
{
if (!inbounds(e, 1))
return 0;
if (*(u8 *) e->pos != code)
return 0;
e->pos++;
return 1;
}
/**
* unpack_nameX - check is the next element is of type X with a name of @name
* @e: serialized data extent information (NOT NULL)
* @code: type code
* @name: name to match to the serialized element. (MAYBE NULL)
*
* check that the next serialized data element is of type X and has a tag
* name @name. If @name is specified then there must be a matching
* name element in the stream. If @name is NULL any name element will be
* skipped and only the typecode will be tested.
*
* Returns 1 on success (both type code and name tests match) and the read
* head is advanced past the headers
*
* Returns: 0 if either match fails, the read head does not move
*/
static bool unpack_nameX(struct aa_ext *e, enum aa_code code, const char *name)
{
/*
* May need to reset pos if name or type doesn't match
*/
void *pos = e->pos;
/*
* Check for presence of a tagname, and if present name size
* AA_NAME tag value is a u16.
*/
if (unpack_X(e, AA_NAME)) {
char *tag = NULL;
size_t size = unpack_u16_chunk(e, &tag);
/* if a name is specified it must match. otherwise skip tag */
if (name && (!size || strcmp(name, tag)))
goto fail;
} else if (name) {
/* if a name is specified and there is no name tag fail */
goto fail;
}
/* now check if type code matches */
if (unpack_X(e, code))
return 1;
fail:
e->pos = pos;
return 0;
}
static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
{
if (unpack_nameX(e, AA_U32, name)) {
if (!inbounds(e, sizeof(u32)))
return 0;
if (data)
*data = le32_to_cpu(get_unaligned((u32 *) e->pos));
e->pos += sizeof(u32);
return 1;
}
return 0;
}
static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
{
if (unpack_nameX(e,
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