selinux/checkpolicy/policy_scan.l

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/*
* Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
*/
/* Updated: David Caplan, <dac@tresys.com>
*
* Added conditional policy language extensions
*
* Jason Tang <jtang@tresys.com>
*
* Added support for binary policy modules
*
* Copyright (C) 2003-5 Tresys Technology, LLC
* Copyright (C) 2017 Mellanox Technologies Inc.
* 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.
*/
/* FLASK */
%{
#include <sys/types.h>
#include <ctype.h>
#include <limits.h>
#include <stdint.h>
#include <string.h>
typedef int (* require_func_t)(void);
#ifdef ANDROID
#include "policy_parse.h"
#else
#include "y.tab.h"
#endif
static char linebuf[2][255];
static unsigned int lno = 0;
int werror = 0;
int yyerror(const char *msg);
int yywarn(const char *msg);
void set_source_file(const char *name);
char source_file[PATH_MAX];
unsigned long source_lineno = 1;
unsigned long policydb_lineno = 1;
unsigned int policydb_errors = 0;
%}
%option noinput nounput noyywrap
%array
letter [A-Za-z]
digit [0-9]
alnum [a-zA-Z0-9]
hexval [0-9A-Fa-f]
%%
\n.* {
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-truncation"
#endif
strncpy(linebuf[lno], yytext+1, 255);
#if defined(__GNUC__) && __GNUC__ >= 8
#pragma GCC diagnostic pop
#endif
linebuf[lno][254] = 0;
lno = 1 - lno;
policydb_lineno++;
if (source_lineno == ULONG_MAX)
yywarn("source line number overflow");
else
source_lineno++;
yyless(1);
}
COMMON |
common { return(COMMON); }
CLASS |
class { return(CLASS); }
CONSTRAIN |
constrain { return(CONSTRAIN); }
VALIDATETRANS |
validatetrans { return(VALIDATETRANS); }
INHERITS |
inherits { return(INHERITS); }
SID |
sid { return(SID); }
ROLE |
role { return(ROLE); }
ROLES |
roles { return(ROLES); }
ROLEATTRIBUTE |
roleattribute { return(ROLEATTRIBUTE);}
ATTRIBUTE_ROLE |
attribute_role { return(ATTRIBUTE_ROLE);}
TYPES |
types { return(TYPES); }
TYPEALIAS |
typealias { return(TYPEALIAS); }
TYPEATTRIBUTE |
typeattribute { return(TYPEATTRIBUTE); }
TYPEBOUNDS |
typebounds { return(TYPEBOUNDS); }
TYPE |
type { return(TYPE); }
BOOL |
bool { return(BOOL); }
TUNABLE |
tunable { return(TUNABLE); }
IF |
if { return(IF); }
ELSE |
else { return(ELSE); }
ALIAS |
alias { return(ALIAS); }
ATTRIBUTE |
attribute { return(ATTRIBUTE); }
Add attribute expansion options This commit adds attribute expansion statements to the policy language allowing compiler defaults to be overridden. Always expands an attribute example: expandattribute { foo } true; CIL example: (expandtypeattribute (foo) true) Never expand an attribute example: expandattribute { bar } false; CIL example: (expandtypeattribute (bar) false) Adding the annotations directly to policy was chosen over other methods as it is consistent with how targeted runtime optimizations are specified in other languages. For example, in C the "inline" command. Motivation expandattribute true: Android has been moving away from a monolithic policy binary to a two part split policy representing the Android platform and the underlying vendor-provided hardware interface. The goal is a stable API allowing these two parts to be updated independently of each other. Attributes provide an important mechanism for compatibility. For example, when the vendor provides a HAL for the platform, permissions needed by clients of the HAL can be granted to an attribute. Clients need only be assigned the attribute and do not need to be aware of the underlying types and permissions being granted. Inheriting permissions via attribute creates a convenient mechanism for independence between vendor and platform policy, but results in the creation of many attributes, and the potential for performance issues when processes are clients of many HALs. [1] Annotating these attributes for expansion at compile time allows us to retain the compatibility benefits of using attributes without the performance costs. [2] expandattribute false: Commit 0be23c3f15fd added the capability to aggresively remove unused attributes. This is generally useful as too many attributes assigned to a type results in lengthy policy look up times when there is a cache miss. However, removing attributes can also result in loss of information used in external tests. On Android, we're considering stripping neverallow rules from on-device policy. This is consistent with the kernel policy binary which also did not contain neverallows. Removing neverallow rules results in a 5-10% decrease in on-device policy build and load and a policy size decrease of ~250k. Neverallow rules are still asserted at build time and during device certification (CTS). If neverallow rules are absent when secilc is run, some attributes are being stripped from policy and neverallow tests in CTS may be violated. [3] This change retains the aggressive attribute stripping behavior but adds an override mechanism to preserve attributes marked as necessary. [1] https://github.com/SELinuxProject/cil/issues/9 [2] Annotating all HAL client attributes for expansion resulted in system_server's dropping from 19 attributes to 8. Because these attributes were not widely applied to other types, the final policy size change was negligible. [3] data_file_type and service_manager_type are stripped from AOSP policy when using secilc's -G option. This impacts 11 neverallow tests in CTS. Test: Build and boot Marlin with all hal_*_client attributes marked for expansion. Verify (using seinfo and sesearch) that permissions are correctly expanded from attributes to types. Test: Mark types being stripped by secilc with "preserve" and verify that they are retained in policy and applied to the same types. Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
2017-05-04 21:36:49 +00:00
EXPANDATTRIBUTE |
expandattribute { return(EXPANDATTRIBUTE); }
TYPE_TRANSITION |
type_transition { return(TYPE_TRANSITION); }
TYPE_MEMBER |
type_member { return(TYPE_MEMBER); }
TYPE_CHANGE |
type_change { return(TYPE_CHANGE); }
ROLE_TRANSITION |
role_transition { return(ROLE_TRANSITION); }
RANGE_TRANSITION |
range_transition { return(RANGE_TRANSITION); }
SENSITIVITY |
sensitivity { return(SENSITIVITY); }
DOMINANCE |
dominance { return(DOMINANCE); }
CATEGORY |
category { return(CATEGORY); }
LEVEL |
level { return(LEVEL); }
RANGE |
range { return(RANGE); }
MLSCONSTRAIN |
mlsconstrain { return(MLSCONSTRAIN); }
MLSVALIDATETRANS |
mlsvalidatetrans { return(MLSVALIDATETRANS); }
USER |
user { return(USER); }
NEVERALLOW |
neverallow { return(NEVERALLOW); }
ALLOW |
allow { return(ALLOW); }
AUDITALLOW |
auditallow { return(AUDITALLOW); }
AUDITDENY |
auditdeny { return(AUDITDENY); }
DONTAUDIT |
dontaudit { return(DONTAUDIT); }
ALLOWXPERM |
allowxperm { return(ALLOWXPERM); }
AUDITALLOWXPERM |
auditallowxperm { return(AUDITALLOWXPERM); }
DONTAUDITXPERM |
dontauditxperm { return(DONTAUDITXPERM); }
NEVERALLOWXPERM |
neverallowxperm { return(NEVERALLOWXPERM); }
SOURCE |
source { return(SOURCE); }
TARGET |
target { return(TARGET); }
SAMEUSER |
sameuser { return(SAMEUSER);}
module|MODULE { return(MODULE); }
require|REQUIRE { return(REQUIRE); }
optional|OPTIONAL { return(OPTIONAL); }
OR |
or { return(OR);}
AND |
and { return(AND);}
NOT |
not { return(NOT);}
xor |
XOR { return(XOR); }
eq |
EQ { return(EQUALS);}
true |
TRUE { return(CTRUE); }
false |
FALSE { return(CFALSE); }
dom |
DOM { return(DOM);}
domby |
DOMBY { return(DOMBY);}
INCOMP |
incomp { return(INCOMP);}
fscon |
FSCON { return(FSCON);}
ibpkeycon |
IBPKEYCON { return(IBPKEYCON);}
ibendportcon |
IBENDPORTCON { return(IBENDPORTCON);}
portcon |
PORTCON { return(PORTCON);}
netifcon |
NETIFCON { return(NETIFCON);}
nodecon |
NODECON { return(NODECON);}
pirqcon |
PIRQCON { return(PIRQCON);}
iomemcon |
IOMEMCON { return(IOMEMCON);}
ioportcon |
IOPORTCON { return(IOPORTCON);}
pcidevicecon |
PCIDEVICECON { return(PCIDEVICECON);}
devicetreecon |
DEVICETREECON { return(DEVICETREECON);}
fs_use_xattr |
FS_USE_XATTR { return(FSUSEXATTR);}
fs_use_task |
FS_USE_TASK { return(FSUSETASK);}
fs_use_trans |
FS_USE_TRANS { return(FSUSETRANS);}
genfscon |
GENFSCON { return(GENFSCON);}
r1 |
R1 { return(R1); }
r2 |
R2 { return(R2); }
r3 |
R3 { return(R3); }
u1 |
U1 { return(U1); }
u2 |
U2 { return(U2); }
u3 |
U3 { return(U3); }
t1 |
T1 { return(T1); }
t2 |
T2 { return(T2); }
t3 |
T3 { return(T3); }
l1 |
L1 { return(L1); }
l2 |
L2 { return(L2); }
h1 |
H1 { return(H1); }
h2 |
H2 { return(H2); }
policycap |
POLICYCAP { return(POLICYCAP); }
permissive |
PERMISSIVE { return(PERMISSIVE); }
default_user |
DEFAULT_USER { return(DEFAULT_USER); }
default_role |
DEFAULT_ROLE { return(DEFAULT_ROLE); }
default_type |
DEFAULT_TYPE { return(DEFAULT_TYPE); }
default_range |
DEFAULT_RANGE { return(DEFAULT_RANGE); }
low-high |
LOW-HIGH { return(LOW_HIGH); }
high |
HIGH { return(HIGH); }
low |
LOW { return(LOW); }
glblub |
GLBLUB { return(GLBLUB); }
"/"[^ \n\r\t\f]* { return(PATH); }
\""/"[^\"\n]*\" { return(QPATH); }
\"[^"/"\"\n]+\" { return(FILENAME); }
{letter}({alnum}|[_\-])*([\.]?({alnum}|[_\-]))* { return(IDENTIFIER); }
{digit}+|0x{hexval}+ { return(NUMBER); }
{alnum}*{letter}{alnum}* { return(FILESYSTEM); }
{digit}{1,3}(\.{digit}{1,3}){3} { return(IPV4_ADDR); }
{hexval}{0,4}":"{hexval}{0,4}":"({hexval}|[:.])* { return(IPV6_ADDR); }
{digit}+(\.({alnum}|[_.])*)? { return(VERSION_IDENTIFIER); }
#line[ ]1[ ]\"[^\n]*\" { set_source_file(yytext+9); }
#line[ ]{digit}+ {
errno = 0;
source_lineno = strtoul(yytext+6, NULL, 10) - 1;
if (errno) {
yywarn("source line number too big");
}
}
#[^\n]* { /* delete comments */ }
[ \t\f]+ { /* delete whitespace */ }
"==" { return(EQUALS); }
"!=" { return (NOTEQUAL); }
"&&" { return (AND); }
"||" { return (OR); }
"!" { return (NOT); }
"^" { return (XOR); }
"," |
":" |
";" |
"(" |
")" |
"{" |
"}" |
"[" |
"-" |
"." |
"]" |
"~" |
"*" { return(yytext[0]); }
. { yyerror("unrecognized character");
/* Available since bison 3.6, avoids duplicate error message */
#ifdef YYerror
return YYerror;
#else
return INVALID_CHAR;
#endif
}
%%
int yyerror(const char *msg)
{
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
const char *token;
char buf[8];
if (isprint((unsigned char)yytext[0])) {
token = yytext;
} else {
snprintf(buf, sizeof(buf), "%#x", yytext[0]);
token = buf;
}
if (source_file[0])
fprintf(stderr, "%s:%lu:",
source_file, source_lineno);
else
fprintf(stderr, "(unknown source)::");
fprintf(stderr, "ERROR '%s' at token '%s' on line %lu:\n%s\n%s\n",
msg,
token,
policydb_lineno,
linebuf[0], linebuf[1]);
#else
(void)msg;
#endif
policydb_errors++;
return -1;
}
int yywarn(const char *msg)
{
if (werror)
return yyerror(msg);
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
if (source_file[0])
fprintf(stderr, "%s:%lu:",
source_file, source_lineno);
else
fprintf(stderr, "(unknown source)::");
fprintf(stderr, "WARNING '%s' at token '%s' on line %lu:\n%s\n%s\n",
msg,
yytext,
policydb_lineno,
linebuf[0], linebuf[1]);
#endif
return 0;
}
void set_source_file(const char *name)
{
source_lineno = 1;
strncpy(source_file, name, sizeof(source_file)-1);
source_file[sizeof(source_file)-1] = '\0';
if (strlen(source_file) && source_file[strlen(source_file)-1] == '"')
source_file[strlen(source_file)-1] = '\0';
}