apparmor/parser/parser_common.c

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/*
* Copyright (c) 2010 - 2012
* Canonical Ltd. (All rights reserved)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, contact Novell, Inc. or Canonical,
* Ltd.
*/
#include <stdlib.h>
#include <stdarg.h>
#include "parser.h"
Add the ability to separate policy_version from kernel and parser abi This will allow for the parser to invalidate its caches separate of whether the kernel policy version has changed. This can be desirable if a parser bug is discovered, a new version the parser is shipped and we need to force cache files to be regenerated. Policy current stores a 32 bit version number in the header binary policy. For newer policy (> v5 kernel abi) split this number into 3 separate fields policy_version, parser_abi, kernel_abi. If binary policy with a split version number is loaded to an older kernel it will be correctly rejected as unsupported as those kernels will see it as a none v5 version. For kernels that only support v5 policy on the kernel abi version is written. The rules for policy versioning should be policy_version: Set by text policy language version. Parsers that don't understand a specified version may fail, or drop rules they are unaware of. parser_abi_version: gets bumped when a userspace bug is discovered that requires policy be recompiled. The policy version could be reset for each new kernel version but since the parser needs to support multiple kernel versions tracking this is extra work and should be avoided. kernel_abi_version: gets bumped when semantic changes need to be applied. Eg unix domain sockets being mediated at connect. the kernel abi version does not encapsulate all supported features. As kernels could have different sets of patches supplied. Basic feature support is determined by the policy_mediates() encoding in the policydb. As such comparing cache features to kernel features is still needed to determine if cached policy is best matched to the kernel. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
2014-04-23 11:00:32 -07:00
/* Policy versioning is determined by a combination of 3 values:
* policy_version: version of txt policy
* parser_abi_version: version of abi revision of policy generated by parser
* kernel_abi_version: version of abi revision for the kernel
*
* The version info is stored in a single 32 bit version field in the
* header portion of each binary policy file.
*
* policy_version:
* a gross revision number indicating what features and semantics are
* expected by the text policy. This does not necessarily map directly
* to a feature set as a kernel may not have all the supported features
* patched/builtin.
*
* policy_version is not supported by kernels that only support v5
* kernel abi, so it will not be written when creating policy for
* those kernels.
*
* kernel_abi_version:
* should be set to the highest version supported by both the parser and
* the kernel.
* This allows new kernels to detect old userspaces, and new parsers
* to support old kernels and policies semantics.
*
* parser_abi_version:
* should be bumped when a compiler error or some other event happens
* and policy cache needs to be forced to be recomputed, when the
* policy_version or kernel version has not changed.
*
* parser_abi_version is not supported by kernels that only support
* v5 kernel abi so it will not be written when creating policy for those
* kernels.
*
* Default values set to v5 kernel abi before the different versioning
* numbers where supported.
*/
uint32_t policy_version = 2;
uint32_t parser_abi_version = 2;
Add the ability to separate policy_version from kernel and parser abi This will allow for the parser to invalidate its caches separate of whether the kernel policy version has changed. This can be desirable if a parser bug is discovered, a new version the parser is shipped and we need to force cache files to be regenerated. Policy current stores a 32 bit version number in the header binary policy. For newer policy (> v5 kernel abi) split this number into 3 separate fields policy_version, parser_abi, kernel_abi. If binary policy with a split version number is loaded to an older kernel it will be correctly rejected as unsupported as those kernels will see it as a none v5 version. For kernels that only support v5 policy on the kernel abi version is written. The rules for policy versioning should be policy_version: Set by text policy language version. Parsers that don't understand a specified version may fail, or drop rules they are unaware of. parser_abi_version: gets bumped when a userspace bug is discovered that requires policy be recompiled. The policy version could be reset for each new kernel version but since the parser needs to support multiple kernel versions tracking this is extra work and should be avoided. kernel_abi_version: gets bumped when semantic changes need to be applied. Eg unix domain sockets being mediated at connect. the kernel abi version does not encapsulate all supported features. As kernels could have different sets of patches supplied. Basic feature support is determined by the policy_mediates() encoding in the policydb. As such comparing cache features to kernel features is still needed to determine if cached policy is best matched to the kernel. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
2014-04-23 11:00:32 -07:00
uint32_t kernel_abi_version = 5;
int force_complain = 0;
int perms_create = 0; /* perms contain create flag */
int net_af_max_override = -1; /* use kernel to determine af_max */
int kernel_load = 1;
Fix profile loads from cache files that contain multiple profiles v3: fix freeing of filename when undefined v2: address tyhicks feedback refactor to have a common write routine fix issue with set profile load being done even if !kernel_load Profile loads from cache files that contain multiple profiles can result in multiple reloads of the same profile or error messages about failure to load profiles if the --add option is used. eg. apparmor="STATUS" operation="profile_load" name="/usr/lib/apache2/mpm-prefork/apache2" pid=8631 comm="apparmor_parser" <sth0R> [82932.058388] type=1400 audit(1395415826.937:616): apparmor="STATUS" operation="profile_load" name="DEFAULT_URI" pid=8631 comm="apparmor_parser" <sth0R> [82932.058391] type=1400 audit(1395415826.937:617): apparmor="STATUS" operation="profile_load" name="HANDLING_UNTRUSTED_INPUT" pid=8631 comm="apparmor_parser" <sth0R> [82932.058394] type=1400 audit(1395415826.937:618): apparmor="STATUS" operation="profile_load" name="phpsysinfo" pid=8631 comm="apparmor_parser" <sth0R> [82932.059058] type=1400 audit(1395415826.937:619): apparmor="STATUS" operation="profile_replace" info="profile can not be replaced" error=-17 name="/usr/lib/apache2/mpm-prefork/apache2//DEFAULT_URI" pid=8631 comm="apparmor_parser" <sth0R> [82932.059574] type=1400 audit(1395415826.937:620): apparmor="STATUS" operation="profile_replace" info="profile can not be replaced" error=-17 name="/usr/lib/apache2/mpm-prefork/apache2//HANDLING_UNTRUSTED_INPUT" pid=8631 comm="apparmor_parser" The reason this happens is that the cache file is a container that can contain multiple profiles in sequential order profile1 profile2 profile3 The parser loads the entire cache file to memory and the writes the whole file to the kernel interface. It then skips foward in the file to the next profile and reloads the file from that profile into the kernel. eg. First load profile1 profile2 profile3 advance to profile2, do second load profile2 profile3 advance to profile3, do third load profile3 With older kernels the interface would stop after the first profile and return that it had processed the whole file, thus while wasting compute resources copying extra data no errors occurred. However newer kernels now support atomic loading of multipe profiles, so that all the profiles passed in to the interface get processed. This means on newer kernels the current parser load behavior results in multiple loads/replacements when a cache file contains more than one profile (note: loads from a compile do not have this problem). To fix this, detect if the kernel supports atomic set loads, and load the cache file once. If it doesn't only load one profile section from a cache file at a time. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
2014-05-08 09:03:13 -07:00
int kernel_supports_setload = 0; /* kernel supports atomic set loads */
int kernel_supports_network = 0; /* kernel supports network rules */
parser: first step implementing fine grained mediation for unix domain sockets This patch implements parsing of fine grained mediation for unix domain sockets, that have abstract and anonymous paths. Sockets with file system paths are handled by regular file access rules. The unix network rules follow the general fine grained network rule pattern of [<qualifiers>] af_name [<access expr>] [<rule conds>] [<local expr>] [<peer expr>] specifically for af_unix this is [<qualifiers>] 'unix' [<access expr>] [<rule conds>] [<local expr>] [<peer expr>] <qualifiers> = [ 'audit' ] [ 'allow' | 'deny' ] <access expr> = ( <access> | <access list> ) <access> = ( 'server' | 'create' | 'bind' | 'listen' | 'accept' | 'connect' | 'shutdown' | 'getattr' | 'setattr' | 'getopt' | 'setopt' | 'send' | 'receive' | 'r' | 'w' | 'rw' ) (some access modes are incompatible with some rules or require additional parameters) <access list> = '(' <access> ( [','] <WS> <access> )* ')' <WS> = white space <rule conds> = ( <type cond> | <protocol cond> )* each cond can appear at most once <type cond> = 'type' '=' ( <AARE> | '(' ( '"' <AARE> '"' | <AARE> )+ ')' ) <protocol cond> = 'protocol' '=' ( <AARE> | '(' ( '"' <AARE> '"' | <AARE> )+ ')' ) <local expr> = ( <path cond> | <attr cond> | <opt cond> )* each cond can appear at most once <peer expr> = 'peer' '=' ( <path cond> | <label cond> )+ each cond can appear at most once <path cond> = 'path' '=' ( <AARE> | '(' '"' <AARE> '"' | <AARE> ')' ) <label cond> = 'label' '=' ( <AARE> | '(' '"' <AARE> '"' | <AARE> ')') <attr cond> = 'attr' '=' ( <AARE> | '(' '"' <AARE> '"' | <AARE> ')' ) <opt cond> = 'opt' '=' ( <AARE> | '(' '"' <AARE> '"' | <AARE> ')' ) <AARE> = ?*[]{}^ ( see man page ) unix domain socket rules are accumulated so that the granted unix socket permissions are the union of all the listed unix rule permissions. unix domain socket rules are broad and general and become more restrictive as further information is specified. Policy may be specified down to the path and label level. The content of the communication is not examined. Some permissions are not compatible with all unix rules. unix socket rule permissions are implied when a rule does not explicitly state an access list. By default if a rule does not have an access list all permissions that are compatible with the specified set of local and peer conditionals are implied. The 'server', 'r', 'w' and 'rw' permissions are aliases for other permissions. server = (create, bind, listen, accept) r = (receive, getattr, getopt) w = (create, connect, send, setattr, setopt) In addition it supports the v7 kernel abi semantics around generic network rules. The v7 abi removes the masking unix and netlink address families from the generic masking and uses fine grained mediation for an address type if supplied. This means that the rules network unix, network netlink, are now enforced instead of ignored. The parser previously could accept these but the kernel would ignore anything written to them. If a network rule is supplied it takes precedence over the finer grained mediation rule. If permission is not granted via a broad network access rule fine grained mediation is applied. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
2014-09-03 13:22:26 -07:00
int kernel_supports_unix = 0; /* kernel supports unix socket rules */
int kernel_supports_policydb = 0; /* kernel supports new policydb */
int kernel_supports_mount = 0; /* kernel supports mount rules */
int kernel_supports_dbus = 0; /* kernel supports dbus rules */
int kernel_supports_diff_encode = 0; /* kernel supports diff_encode */
int kernel_supports_signal = 0; /* kernel supports signal rules */
int kernel_supports_ptrace = 0; /* kernel supports ptrace rules */
int kernel_supports_stacking = 0; /* kernel supports stacking */
int conf_verbose = 0;
int conf_quiet = 0;
int names_only = 0;
int current_lineno = 1;
int option = OPTION_ADD;
dfaflags_t dfaflags = (dfaflags_t)(DFA_CONTROL_TREE_NORMAL | DFA_CONTROL_TREE_SIMPLE | DFA_CONTROL_MINIMIZE | DFA_CONTROL_DIFF_ENCODE);
dfaflags_t warnflags = 0;
const char *progname = __FILE__;
char *profile_ns = NULL;
char *profilename = NULL;
char *current_filename = NULL;
FILE *ofile = NULL;
#ifdef FORCE_READ_IMPLIES_EXEC
int read_implies_exec = 1;
#else
int read_implies_exec = 0;
#endif
void pwarn(const char *fmt, ...)
{
va_list arg;
char *newfmt;
if (conf_quiet || names_only || option == OPTION_REMOVE)
return;
if (asprintf(&newfmt, _("Warning from %s (%s%sline %d): %s"),
profilename ? profilename : "stdin",
current_filename ? current_filename : "",
current_filename ? " " : "",
current_lineno,
fmt) == -1)
return;
va_start(arg, fmt);
vfprintf(stderr, newfmt, arg);
va_end(arg);
free(newfmt);
}