apparmor/parser/libapparmor_re/policy_compat.cc
John Johansen 15a02e0948 parser: fix mapping of AA_CONT_MATCH for policydb compat entries
The mapping of AA_CONT_MATCH was being dropped resulting in the
tcp tests failing because they would only match up to the first conditional
match check in the layout.

Bug: https://gitlab.com/apparmor/apparmor/-/issues/462
Fixes: e29f5ce5f ("parser: if extended perms are supported by the kernel build a permstable")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2024-11-06 12:33:36 -08:00

220 lines
6.8 KiB
C++

/*
* Copyright (c) 2022
* 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.
*/
/*
* This is a set of functions to provide convertion from old style permission
* mappings, to new style kernel mappings. It is based on the kernel to
* as the kernel needs this for backwards compatibility. This allows the
* userspace to convert to the new permission mapping without reworking
* the internal dfa permission tracking.
*
* In the future this code will be converted to go the reverse direction
* i.e. new mappings into old, which the parser will need for backwards
* compat with old kernels.
*/
#include <stdint.h>
#include <iostream>
#include "policy_compat.h"
#include "../perms.h"
#include "../rule.h"
extern int prompt_compat_mode;
/* remap old accept table embedded permissions to separate permission table */
static uint32_t dfa_map_xindex(uint16_t mask)
{
uint16_t old_index = (mask >> 10) & 0xf;
uint32_t index = 0;
if (mask & 0x100)
index |= AA_X_UNSAFE;
if (mask & 0x200)
index |= AA_X_INHERIT;
if (mask & 0x80)
index |= AA_X_UNCONFINED;
if (old_index == 1) {
index |= AA_X_UNCONFINED;
} else if (old_index == 2) {
index |= AA_X_NAME;
} else if (old_index == 3) {
index |= AA_X_NAME | AA_X_CHILD;
} else if (old_index) {
index |= AA_X_TABLE;
index |= old_index - 4;
}
return index;
}
/*
* map old dfa inline permissions to new format
*/
#define dfa_user_allow(accept1) (((accept1) & 0x7f) | \
((accept1) & 0x80000000))
#define dfa_user_xbits(accept1) (((accept1) >> 7) & 0x7f)
#define dfa_user_audit(accept1, accept2) ((accept2) & 0x7f)
#define dfa_user_quiet(accept1, accept2) (((accept2) >> 7) & 0x7f)
#define dfa_user_xindex(accept1) \
(dfa_map_xindex(accept1 & 0x3fff))
#define dfa_other_allow(accept1) ((((accept1) >> 14) & \
0x7f) | \
((accept1) & 0x80000000))
#define dfa_other_xbits(accept1) \
((((accept1) >> 7) >> 14) & 0x7f)
#define dfa_other_audit(accept1, accept2) (((accept2) >> 14) & 0x7f)
#define dfa_other_quiet(accept1, accept2) \
((((accept2) >> 7) >> 14) & 0x7f)
#define dfa_other_xindex(accept1) \
dfa_map_xindex((accept1 >> 14) & 0x3fff)
/**
* map_old_perms - map old file perms layout to the new layout
* @old: permission set in old mapping
*
* Returns: new permission mapping
*/
static uint32_t map_old_perms(uint32_t old)
{
uint32_t perm = old & 0xf;
if (old & AA_MAY_READ)
perm |= AA_MAY_GETATTR | AA_MAY_OPEN;
if (old & AA_MAY_WRITE)
perm |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE |
AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN;
if (old & 0x10)
perm |= AA_MAY_LINK;
/* the old mapping lock and link_subset flags where overlaid
* and use was determined by part of a pair that they were in
*/
if (old & 0x20)
perm |= AA_MAY_LOCK | AA_LINK_SUBSET;
if (old & 0x40) /* AA_EXEC_MMAP */
perm |= AA_EXEC_MMAP;
return perm;
}
static void compute_fperms_allow(struct aa_perms *perms, uint32_t accept1)
{
perms->allow |= AA_MAY_GETATTR;
/* change_profile wasn't determined by ownership in old mapping */
if (accept1 & 0x80000000)
perms->allow |= AA_MAY_CHANGE_PROFILE;
if (accept1 & 0x40000000)
perms->allow |= AA_MAY_ONEXEC;
}
struct aa_perms compute_fperms_user(uint32_t accept1, uint32_t accept2,
uint32_t accept3)
{
struct aa_perms perms = { };
perms.allow = map_old_perms(dfa_user_allow(accept1));
perms.prompt = map_old_perms(dfa_user_allow(accept3));
perms.audit = map_old_perms(dfa_user_audit(accept1, accept2));
perms.quiet = map_old_perms(dfa_user_quiet(accept1, accept2));
if (prompt_compat_mode != PROMPT_COMPAT_PERMSV1)
perms.xindex = dfa_user_xindex(accept1);
compute_fperms_allow(&perms, accept1);
perms.prompt &= ~(perms.allow | perms.deny);
return perms;
}
struct aa_perms compute_fperms_other(uint32_t accept1, uint32_t accept2,
uint32_t accept3)
{
struct aa_perms perms = { };
perms.allow = map_old_perms(dfa_other_allow(accept1));
perms.prompt = map_old_perms(dfa_other_allow(accept3));
perms.audit = map_old_perms(dfa_other_audit(accept1, accept2));
perms.quiet = map_old_perms(dfa_other_quiet(accept1, accept2));
if (prompt_compat_mode != PROMPT_COMPAT_PERMSV1)
perms.xindex = dfa_other_xindex(accept1);
compute_fperms_allow(&perms, accept1);
perms.prompt &= ~(perms.allow | perms.deny);
return perms;
}
static uint32_t map_other(uint32_t x)
{
return ((x & 0x3) << 8) | /* SETATTR/GETATTR */
((x & 0x1c) << 18) | /* ACCEPT/BIND/LISTEN */
((x & 0x60) << 19); /* SETOPT/GETOPT */
}
static uint32_t map_xbits(uint32_t x)
{
return ((x & 0x1) << 7) |
((x & 0x7e) << 9);
}
struct aa_perms compute_perms_entry(uint32_t accept1, uint32_t accept2,
uint32_t accept3)
// don't need to worry about version internally within the parser
// uint32_t version)
{
struct aa_perms perms = { };
perms.allow = dfa_user_allow(accept1);
perms.prompt = dfa_user_allow(accept3);
perms.audit = dfa_user_audit(accept1, accept2);
perms.quiet = dfa_user_quiet(accept1, accept2);
if (accept1 & AA_COMPAT_CONT_MATCH)
perms.allow |= AA_CONT_MATCH;
/*
* This mapping is convulated due to history.
* v1-v4: only file perms, which are handled by compute_fperms
* v5: added policydb which dropped user conditional to gain new
* perm bits, but had to map around the xbits because the
* userspace compiler was still munging them.
* v9: adds using the xbits in policydb because the compiler now
* supports treating policydb permission bits different.
* Unfortunately there is no way to force auditing on the
* perms represented by the xbits
*/
perms.allow |= map_other(dfa_other_allow(accept1));
// v9 encoding never rolled out. AA_MAY_LOCK needed to fix
// non fs unix locking see kernel commit
// 1cf26c3d2c4c apparmor: fix apparmor mediating locking non-fs unix sockets
//if (VERSION_LE(version, v8))
perms.allow |= AA_MAY_LOCK;
//else
// perms.allow |= map_xbits(dfa_user_xbits(dfa, state));
/*
* for v5-v9 perm mapping in the policydb, the other set is used
* to extend the general perm set
*/
perms.prompt |= map_other(dfa_other_allow(accept3));
perms.audit |= map_other(dfa_other_audit(accept1, accept2));
perms.quiet |= map_other(dfa_other_quiet(accept1, accept2));
//if (VERSION_GT(version, v8))
// perms.quiet |= map_xbits(dfa_other_xbits(dfa, state));
return perms;
}