opnsense-src/sys/compat/linux/linux_uid16.c
Kyle Evans be1f7435ef kern: start tracking cr_gid outside of cr_groups[]
This is the (mostly) kernel side of de-conflating cr_gid and the
supplemental groups.  The pre-existing behavior for getgroups() and
setgroups() is retained to keep the user <-> kernel boundary
functionally the same while we audit use of these syscalls, but we can
remove a lot of the internal special-casing just by reorganizing ucred
like this.

struct xucred has been altered because the cr_gid macro becomes
problematic if ucred has a real cr_gid member but xucred does not.  Most
notably, they both also have cr_groups[] members, so the definition
means that we could easily have situations where we end up using the
first supplemental group as the egid in some places.  We really can't
change the ABI of xucred, so instead we alias the first member to the
`cr_gid` name and maintain the status quo.

This also fixes the Linux setgroups(2)/getgroups(2) implementation to
more cleanly preserve the group set, now that we don't need to special
case cr_groups[0].

__FreeBSD_version bumped for the `struct ucred` ABI break.

For relnotes: downstreams and out-of-tree modules absolutely must fix
any references to cr_groups[0] in their code.  These are almost
exclusively incorrect in the new world, and cr_gid should be used
instead.  There is a cr_gid macro available in earlier FreeBSD versions
that can be used to avoid having version-dependant conditionals to refer
to the effective group id.  Surrounding code may need adjusted if it
peels off the first element of cr_groups and uses the others as the
supplemental groups, since the supplemental groups start at cr_groups[0]
now if &cr_groups[0] != &cr_gid.

Relnotes:	yes (see last paragraph)
Co-authored-by:	olce
Differential Revision:	https://reviews.freebsd.org/D51489
2025-07-30 23:44:11 -05:00

288 lines
6.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2001 The FreeBSD Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif
#include <compat/linux/linux_dtrace.h>
#include <compat/linux/linux_util.h>
/* DTrace init */
LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
/**
* DTrace probes in this module.
*/
LIN_SDT_PROBE_DEFINE1(uid16, linux_chown16, conv_path, "char *");
LIN_SDT_PROBE_DEFINE1(uid16, linux_lchown16, conv_path, "char *");
LIN_SDT_PROBE_DEFINE1(uid16, linux_setgroups16, copyin_error, "int");
LIN_SDT_PROBE_DEFINE1(uid16, linux_setgroups16, priv_check_cred_error, "int");
LIN_SDT_PROBE_DEFINE1(uid16, linux_getgroups16, copyout_error, "int");
DUMMY(setfsuid16);
DUMMY(setfsgid16);
DUMMY(getresuid16);
DUMMY(getresgid16);
#define CAST_NOCHG(x) ((x == 0xFFFF) ? -1 : x)
int
linux_chown16(struct thread *td, struct linux_chown16_args *args)
{
return (kern_fchownat(td, AT_FDCWD, args->path, UIO_USERSPACE,
CAST_NOCHG(args->uid), CAST_NOCHG(args->gid), 0));
}
int
linux_lchown16(struct thread *td, struct linux_lchown16_args *args)
{
return (kern_fchownat(td, AT_FDCWD, args->path, UIO_USERSPACE,
CAST_NOCHG(args->uid), CAST_NOCHG(args->gid), AT_SYMLINK_NOFOLLOW));
}
int
linux_setgroups16(struct thread *td, struct linux_setgroups16_args *args)
{
struct ucred *newcred, *oldcred;
l_gid16_t *linux_gidset;
int ngrp, error;
struct proc *p;
ngrp = args->gidsetsize;
if (ngrp < 0 || ngrp >= ngroups_max)
return (EINVAL);
linux_gidset = malloc(ngrp * sizeof(*linux_gidset), M_LINUX, M_WAITOK);
error = copyin(args->gidset, linux_gidset, ngrp * sizeof(l_gid16_t));
if (error) {
LIN_SDT_PROBE1(uid16, linux_setgroups16, copyin_error, error);
free(linux_gidset, M_LINUX);
return (error);
}
newcred = crget();
p = td->td_proc;
PROC_LOCK(p);
oldcred = crcopysafe(p, newcred);
if ((error = priv_check_cred(oldcred, PRIV_CRED_SETGROUPS)) != 0) {
PROC_UNLOCK(p);
crfree(newcred);
LIN_SDT_PROBE1(uid16, linux_setgroups16, priv_check_cred_error,
error);
goto out;
}
newcred->cr_ngroups = ngrp;
for (int i = 0; i < ngrp; i++)
newcred->cr_groups[i] = linux_gidset[i];
setsugid(td->td_proc);
proc_set_cred(p, newcred);
PROC_UNLOCK(p);
crfree(oldcred);
error = 0;
out:
free(linux_gidset, M_LINUX);
return (error);
}
int
linux_getgroups16(struct thread *td, struct linux_getgroups16_args *args)
{
struct ucred *cred;
l_gid16_t *linux_gidset;
gid_t *bsd_gidset;
int bsd_gidsetsz, ngrp, error;
cred = td->td_ucred;
bsd_gidset = cred->cr_groups;
bsd_gidsetsz = cred->cr_ngroups;
if ((ngrp = args->gidsetsize) == 0) {
td->td_retval[0] = bsd_gidsetsz;
return (0);
}
if (ngrp < bsd_gidsetsz)
return (EINVAL);
ngrp = 0;
linux_gidset = malloc(bsd_gidsetsz * sizeof(*linux_gidset),
M_LINUX, M_WAITOK);
while (ngrp < bsd_gidsetsz) {
linux_gidset[ngrp] = bsd_gidset[ngrp];
ngrp++;
}
error = copyout(linux_gidset, args->gidset, ngrp * sizeof(l_gid16_t));
free(linux_gidset, M_LINUX);
if (error) {
LIN_SDT_PROBE1(uid16, linux_getgroups16, copyout_error, error);
return (error);
}
td->td_retval[0] = ngrp;
return (0);
}
int
linux_getgid16(struct thread *td, struct linux_getgid16_args *args)
{
td->td_retval[0] = td->td_ucred->cr_rgid;
return (0);
}
int
linux_getuid16(struct thread *td, struct linux_getuid16_args *args)
{
td->td_retval[0] = td->td_ucred->cr_ruid;
return (0);
}
int
linux_getegid16(struct thread *td, struct linux_getegid16_args *args)
{
struct getegid_args bsd;
int error;
error = sys_getegid(td, &bsd);
return (error);
}
int
linux_geteuid16(struct thread *td, struct linux_geteuid16_args *args)
{
struct geteuid_args bsd;
int error;
error = sys_geteuid(td, &bsd);
return (error);
}
int
linux_setgid16(struct thread *td, struct linux_setgid16_args *args)
{
struct setgid_args bsd;
int error;
bsd.gid = args->gid;
error = sys_setgid(td, &bsd);
return (error);
}
int
linux_setuid16(struct thread *td, struct linux_setuid16_args *args)
{
struct setuid_args bsd;
int error;
bsd.uid = args->uid;
error = sys_setuid(td, &bsd);
return (error);
}
int
linux_setregid16(struct thread *td, struct linux_setregid16_args *args)
{
struct setregid_args bsd;
int error;
bsd.rgid = CAST_NOCHG(args->rgid);
bsd.egid = CAST_NOCHG(args->egid);
error = sys_setregid(td, &bsd);
return (error);
}
int
linux_setreuid16(struct thread *td, struct linux_setreuid16_args *args)
{
struct setreuid_args bsd;
int error;
bsd.ruid = CAST_NOCHG(args->ruid);
bsd.euid = CAST_NOCHG(args->euid);
error = sys_setreuid(td, &bsd);
return (error);
}
int
linux_setresgid16(struct thread *td, struct linux_setresgid16_args *args)
{
struct setresgid_args bsd;
int error;
bsd.rgid = CAST_NOCHG(args->rgid);
bsd.egid = CAST_NOCHG(args->egid);
bsd.sgid = CAST_NOCHG(args->sgid);
error = sys_setresgid(td, &bsd);
return (error);
}
int
linux_setresuid16(struct thread *td, struct linux_setresuid16_args *args)
{
struct setresuid_args bsd;
int error;
bsd.ruid = CAST_NOCHG(args->ruid);
bsd.euid = CAST_NOCHG(args->euid);
bsd.suid = CAST_NOCHG(args->suid);
error = sys_setresuid(td, &bsd);
return (error);
}