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s390: use generic UID16 implementation
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s390 has an almost identical copy of the code in kernel/uid16.c.

The problem here is that it requires calling the regular system calls,
which the generic implementation handles correctly, but the internal
interfaces are not declared in a global header for this.

The best way forward here seems to be to just use the generic code and
delete the s390 specific implementation.

I keep the changes to uapi/asm/posix_types.h inside of an #ifdef check
so user space does not observe any changes. As some of the system calls
pass pointers, we also need wrappers in compat_wrapper.c, which I add
for all calls with at least one argument. All those wrappers can be
removed in a later step.

Link: https://lore.kernel.org/lkml/20190116131527.2071570-4-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Arnd Bergmann authored and Martin Schwidefsky committed Jan 18, 2019
1 parent 58fa4a4 commit fef747b
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1 change: 1 addition & 0 deletions arch/s390/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -379,6 +379,7 @@ config COMPAT
select COMPAT_BINFMT_ELF if BINFMT_ELF
select ARCH_WANT_OLD_COMPAT_IPC
select COMPAT_OLD_SIGACTION
select HAVE_UID16
depends on MULTIUSER
help
Select this option if you want to enable your system kernel to
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6 changes: 6 additions & 0 deletions arch/s390/include/uapi/asm/posix_types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,12 @@ typedef long __kernel_ssize_t;
typedef unsigned short __kernel_old_dev_t;
#define __kernel_old_dev_t __kernel_old_dev_t

#ifdef __KERNEL__
typedef unsigned short __kernel_old_uid_t;
typedef unsigned short __kernel_old_gid_t;
#define __kernel_old_uid_t __kernel_old_uid_t
#endif

#ifndef __s390x__

typedef unsigned long __kernel_ino_t;
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233 changes: 0 additions & 233 deletions arch/s390/kernel/compat_linux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,6 @@
#include <linux/stat.h>
#include <linux/filter.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/mman.h>
#include <linux/ipv6.h>
#include <linux/in.h>
Expand All @@ -58,238 +57,6 @@

#include "compat_linux.h"

/* For this source file, we want overflow handling. */

#undef high2lowuid
#undef high2lowgid
#undef low2highuid
#undef low2highgid
#undef SET_UID16
#undef SET_GID16
#undef NEW_TO_OLD_UID
#undef NEW_TO_OLD_GID
#undef SET_OLDSTAT_UID
#undef SET_OLDSTAT_GID
#undef SET_STAT_UID
#undef SET_STAT_GID

#define high2lowuid(uid) ((uid) > 65535) ? (u16)overflowuid : (u16)(uid)
#define high2lowgid(gid) ((gid) > 65535) ? (u16)overflowgid : (u16)(gid)
#define low2highuid(uid) ((uid) == (u16)-1) ? (uid_t)-1 : (uid_t)(uid)
#define low2highgid(gid) ((gid) == (u16)-1) ? (gid_t)-1 : (gid_t)(gid)
#define SET_UID16(var, uid) var = high2lowuid(uid)
#define SET_GID16(var, gid) var = high2lowgid(gid)
#define NEW_TO_OLD_UID(uid) high2lowuid(uid)
#define NEW_TO_OLD_GID(gid) high2lowgid(gid)
#define SET_OLDSTAT_UID(stat, uid) (stat).st_uid = high2lowuid(uid)
#define SET_OLDSTAT_GID(stat, gid) (stat).st_gid = high2lowgid(gid)
#define SET_STAT_UID(stat, uid) (stat).st_uid = high2lowuid(uid)
#define SET_STAT_GID(stat, gid) (stat).st_gid = high2lowgid(gid)

COMPAT_SYSCALL_DEFINE3(s390_chown16, const char __user *, filename,
u16, user, u16, group)
{
return ksys_chown(filename, low2highuid(user), low2highgid(group));
}

COMPAT_SYSCALL_DEFINE3(s390_lchown16, const char __user *,
filename, u16, user, u16, group)
{
return ksys_lchown(filename, low2highuid(user), low2highgid(group));
}

COMPAT_SYSCALL_DEFINE3(s390_fchown16, unsigned int, fd, u16, user, u16, group)
{
return ksys_fchown(fd, low2highuid(user), low2highgid(group));
}

COMPAT_SYSCALL_DEFINE2(s390_setregid16, u16, rgid, u16, egid)
{
return sys_setregid(low2highgid(rgid), low2highgid(egid));
}

COMPAT_SYSCALL_DEFINE1(s390_setgid16, u16, gid)
{
return sys_setgid(low2highgid(gid));
}

COMPAT_SYSCALL_DEFINE2(s390_setreuid16, u16, ruid, u16, euid)
{
return sys_setreuid(low2highuid(ruid), low2highuid(euid));
}

COMPAT_SYSCALL_DEFINE1(s390_setuid16, u16, uid)
{
return sys_setuid(low2highuid(uid));
}

COMPAT_SYSCALL_DEFINE3(s390_setresuid16, u16, ruid, u16, euid, u16, suid)
{
return sys_setresuid(low2highuid(ruid), low2highuid(euid),
low2highuid(suid));
}

COMPAT_SYSCALL_DEFINE3(s390_getresuid16, u16 __user *, ruidp,
u16 __user *, euidp, u16 __user *, suidp)
{
const struct cred *cred = current_cred();
int retval;
u16 ruid, euid, suid;

ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));

if (!(retval = put_user(ruid, ruidp)) &&
!(retval = put_user(euid, euidp)))
retval = put_user(suid, suidp);

return retval;
}

COMPAT_SYSCALL_DEFINE3(s390_setresgid16, u16, rgid, u16, egid, u16, sgid)
{
return sys_setresgid(low2highgid(rgid), low2highgid(egid),
low2highgid(sgid));
}

COMPAT_SYSCALL_DEFINE3(s390_getresgid16, u16 __user *, rgidp,
u16 __user *, egidp, u16 __user *, sgidp)
{
const struct cred *cred = current_cred();
int retval;
u16 rgid, egid, sgid;

rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));

if (!(retval = put_user(rgid, rgidp)) &&
!(retval = put_user(egid, egidp)))
retval = put_user(sgid, sgidp);

return retval;
}

COMPAT_SYSCALL_DEFINE1(s390_setfsuid16, u16, uid)
{
return sys_setfsuid(low2highuid(uid));
}

COMPAT_SYSCALL_DEFINE1(s390_setfsgid16, u16, gid)
{
return sys_setfsgid(low2highgid(gid));
}

static int groups16_to_user(u16 __user *grouplist, struct group_info *group_info)
{
struct user_namespace *user_ns = current_user_ns();
int i;
u16 group;
kgid_t kgid;

for (i = 0; i < group_info->ngroups; i++) {
kgid = group_info->gid[i];
group = (u16)from_kgid_munged(user_ns, kgid);
if (put_user(group, grouplist+i))
return -EFAULT;
}

return 0;
}

static int groups16_from_user(struct group_info *group_info, u16 __user *grouplist)
{
struct user_namespace *user_ns = current_user_ns();
int i;
u16 group;
kgid_t kgid;

for (i = 0; i < group_info->ngroups; i++) {
if (get_user(group, grouplist+i))
return -EFAULT;

kgid = make_kgid(user_ns, (gid_t)group);
if (!gid_valid(kgid))
return -EINVAL;

group_info->gid[i] = kgid;
}

return 0;
}

COMPAT_SYSCALL_DEFINE2(s390_getgroups16, int, gidsetsize, u16 __user *, grouplist)
{
const struct cred *cred = current_cred();
int i;

if (gidsetsize < 0)
return -EINVAL;

get_group_info(cred->group_info);
i = cred->group_info->ngroups;
if (gidsetsize) {
if (i > gidsetsize) {
i = -EINVAL;
goto out;
}
if (groups16_to_user(grouplist, cred->group_info)) {
i = -EFAULT;
goto out;
}
}
out:
put_group_info(cred->group_info);
return i;
}

COMPAT_SYSCALL_DEFINE2(s390_setgroups16, int, gidsetsize, u16 __user *, grouplist)
{
struct group_info *group_info;
int retval;

if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;

group_info = groups_alloc(gidsetsize);
if (!group_info)
return -ENOMEM;
retval = groups16_from_user(group_info, grouplist);
if (retval) {
put_group_info(group_info);
return retval;
}

groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);

return retval;
}

COMPAT_SYSCALL_DEFINE0(s390_getuid16)
{
return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
}

COMPAT_SYSCALL_DEFINE0(s390_geteuid16)
{
return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
}

COMPAT_SYSCALL_DEFINE0(s390_getgid16)
{
return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
}

COMPAT_SYSCALL_DEFINE0(s390_getegid16)
{
return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
}

#ifdef CONFIG_SYSVIPC
COMPAT_SYSCALL_DEFINE5(s390_ipc, uint, call, int, first, compat_ulong_t, second,
compat_ulong_t, third, compat_uptr_t, ptr)
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15 changes: 15 additions & 0 deletions arch/s390/kernel/compat_wrapper.c
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Original file line number Diff line number Diff line change
Expand Up @@ -184,3 +184,18 @@ COMPAT_SYSCALL_WRAP5(statx, int, dfd, const char __user *, path, unsigned, flags
COMPAT_SYSCALL_WRAP4(s390_sthyi, unsigned long, code, void __user *, info, u64 __user *, rc, unsigned long, flags);
COMPAT_SYSCALL_WRAP5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags)
COMPAT_SYSCALL_WRAP4(rseq, struct rseq __user *, rseq, u32, rseq_len, int, flags, u32, sig)
COMPAT_SYSCALL_WRAP3(chown16, const char __user *, filename, u16, user, u16, group);
COMPAT_SYSCALL_WRAP3(lchown16, const char __user *, filename, u16, user, u16, group);
COMPAT_SYSCALL_WRAP3(fchown16, unsigned int, fd, u16, user, u16, group);
COMPAT_SYSCALL_WRAP2(setregid16, u16, rgid, u16, egid);
COMPAT_SYSCALL_WRAP1(setgid16, u16, gid);
COMPAT_SYSCALL_WRAP2(setreuid16, u16, ruid, u16, euid);
COMPAT_SYSCALL_WRAP1(setuid16, u16, uid);
COMPAT_SYSCALL_WRAP3(setresuid16, u16, ruid, u16, euid, u16, suid);
COMPAT_SYSCALL_WRAP3(getresuid16, u16 __user *, ruidp, u16 __user *, euidp, u16 __user *, suidp);
COMPAT_SYSCALL_WRAP3(setresgid16, u16, rgid, u16, egid, u16, sgid);
COMPAT_SYSCALL_WRAP3(getresgid16, u16 __user *, rgidp, u16 __user *, egidp, u16 __user *, sgidp);
COMPAT_SYSCALL_WRAP1(setfsuid16, u16, uid);
COMPAT_SYSCALL_WRAP1(setfsgid16, u16, gid);
COMPAT_SYSCALL_WRAP2(getgroups16, int, gidsetsize, u16 __user *, grouplist);
COMPAT_SYSCALL_WRAP2(setgroups16, int, gidsetsize, u16 __user *, grouplist);
38 changes: 19 additions & 19 deletions arch/s390/kernel/syscalls/syscall.tbl
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Original file line number Diff line number Diff line change
Expand Up @@ -23,13 +23,13 @@
13 32 time - compat_sys_time
14 common mknod sys_mknod compat_sys_mknod
15 common chmod sys_chmod compat_sys_chmod
16 32 lchown - compat_sys_s390_lchown16
16 32 lchown - compat_sys_lchown16
19 common lseek sys_lseek compat_sys_lseek
20 common getpid sys_getpid sys_getpid
21 common mount sys_mount compat_sys_mount
22 common umount sys_oldumount compat_sys_oldumount
23 32 setuid - compat_sys_s390_setuid16
24 32 getuid - compat_sys_s390_getuid16
23 32 setuid - compat_sys_setuid16
24 32 getuid - sys_getuid16
25 32 stime - compat_sys_stime
26 common ptrace sys_ptrace compat_sys_ptrace
27 common alarm sys_alarm sys_alarm
Expand All @@ -46,11 +46,11 @@
42 common pipe sys_pipe compat_sys_pipe
43 common times sys_times compat_sys_times
45 common brk sys_brk compat_sys_brk
46 32 setgid - compat_sys_s390_setgid16
47 32 getgid - compat_sys_s390_getgid16
46 32 setgid - compat_sys_setgid16
47 32 getgid - sys_getgid16
48 common signal sys_signal compat_sys_signal
49 32 geteuid - compat_sys_s390_geteuid16
50 32 getegid - compat_sys_s390_getegid16
49 32 geteuid - sys_geteuid16
50 32 getegid - sys_getegid16
51 common acct sys_acct compat_sys_acct
52 common umount2 sys_umount compat_sys_umount
54 common ioctl sys_ioctl compat_sys_ioctl
Expand All @@ -64,8 +64,8 @@
65 common getpgrp sys_getpgrp sys_getpgrp
66 common setsid sys_setsid sys_setsid
67 common sigaction sys_sigaction compat_sys_sigaction
70 32 setreuid - compat_sys_s390_setreuid16
71 32 setregid - compat_sys_s390_setregid16
70 32 setreuid - compat_sys_setreuid16
71 32 setregid - compat_sys_setregid16
72 common sigsuspend sys_sigsuspend compat_sys_sigsuspend
73 common sigpending sys_sigpending compat_sys_sigpending
74 common sethostname sys_sethostname compat_sys_sethostname
Expand All @@ -74,8 +74,8 @@
77 common getrusage sys_getrusage compat_sys_getrusage
78 common gettimeofday sys_gettimeofday compat_sys_gettimeofday
79 common settimeofday sys_settimeofday compat_sys_settimeofday
80 32 getgroups - compat_sys_s390_getgroups16
81 32 setgroups - compat_sys_s390_setgroups16
80 32 getgroups - compat_sys_getgroups16
81 32 setgroups - compat_sys_setgroups16
83 common symlink sys_symlink compat_sys_symlink
85 common readlink sys_readlink compat_sys_readlink
86 common uselib sys_uselib compat_sys_uselib
Expand All @@ -87,7 +87,7 @@
92 common truncate sys_truncate compat_sys_truncate
93 common ftruncate sys_ftruncate compat_sys_ftruncate
94 common fchmod sys_fchmod sys_fchmod
95 32 fchown - compat_sys_s390_fchown16
95 32 fchown - compat_sys_fchown16
96 common getpriority sys_getpriority sys_getpriority
97 common setpriority sys_setpriority sys_setpriority
99 common statfs sys_statfs compat_sys_statfs
Expand Down Expand Up @@ -126,8 +126,8 @@
135 common sysfs sys_sysfs compat_sys_sysfs
136 common personality sys_s390_personality sys_s390_personality
137 common afs_syscall - -
138 32 setfsuid - compat_sys_s390_setfsuid16
139 32 setfsgid - compat_sys_s390_setfsgid16
138 32 setfsuid - compat_sys_setfsuid16
139 32 setfsgid - compat_sys_setfsgid16
140 32 _llseek - compat_sys_llseek
141 common getdents sys_getdents compat_sys_getdents
142 32 _newselect - compat_sys_select
Expand All @@ -153,13 +153,13 @@
161 common sched_rr_get_interval sys_sched_rr_get_interval compat_sys_sched_rr_get_interval
162 common nanosleep sys_nanosleep compat_sys_nanosleep
163 common mremap sys_mremap compat_sys_mremap
164 32 setresuid - compat_sys_s390_setresuid16
165 32 getresuid - compat_sys_s390_getresuid16
164 32 setresuid - compat_sys_setresuid16
165 32 getresuid - compat_sys_getresuid16
167 common query_module - -
168 common poll sys_poll compat_sys_poll
169 common nfsservctl - -
170 32 setresgid - compat_sys_s390_setresgid16
171 32 getresgid - compat_sys_s390_getresgid16
170 32 setresgid - compat_sys_setresgid16
171 32 getresgid - compat_sys_getresgid16
172 common prctl sys_prctl compat_sys_prctl
173 common rt_sigreturn sys_rt_sigreturn compat_sys_rt_sigreturn
174 common rt_sigaction sys_rt_sigaction compat_sys_rt_sigaction
Expand All @@ -170,7 +170,7 @@
179 common rt_sigsuspend sys_rt_sigsuspend compat_sys_rt_sigsuspend
180 common pread64 sys_pread64 compat_sys_s390_pread64
181 common pwrite64 sys_pwrite64 compat_sys_s390_pwrite64
182 32 chown - compat_sys_s390_chown16
182 32 chown - compat_sys_chown16
183 common getcwd sys_getcwd compat_sys_getcwd
184 common capget sys_capget compat_sys_capget
185 common capset sys_capset compat_sys_capset
Expand Down

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