all arch: remove system call sys_sysctl

Since commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.

We have been warning about people using the sysctl system call for years
and believe there are no more users.  Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.

So completely remove sys_sysctl on all architectures.

[nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu]
 Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org>		[arm/arm64]
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bin Meng <bin.meng@windriver.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: chenzefeng <chenzefeng2@huawei.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Diego Elio Pettenò <flameeyes@flameeyes.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kars de Jong <jongk@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Sven Schnelle <svens@stackframe.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 1 insertions, 173 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index b3da548691c9..9a20016d4900 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -5,7 +5,7 @@
 
 obj-y     = fork.o exec_domain.o panic.o \
 	    cpu.o exit.o softirq.o resource.o \
-	    sysctl.o sysctl_binary.o capability.o ptrace.o user.o \
+	    sysctl.o capability.o ptrace.o user.o \
 	    signal.o sys.o umh.o workqueue.o pid.o task_work.o \
 	    extable.o params.o \
 	    kthread.o sys_ni.o nsproxy.o \
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 3b69a560a7ac..4d59775ea79c 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -364,7 +364,6 @@ COND_SYSCALL(socketcall);
 COND_SYSCALL_COMPAT(socketcall);
 
 /* compat syscalls for arm64, x86, ... */
-COND_SYSCALL_COMPAT(sysctl);
 COND_SYSCALL_COMPAT(fanotify_mark);
 
 /* x86 */
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
deleted file mode 100644
index 7d550cc76a3b..000000000000
--- a/kernel/sysctl_binary.c
+++ /dev/null
@@ -1,171 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/stat.h>
-#include <linux/sysctl.h>
-#include "../fs/xfs/xfs_sysctl.h"
-#include <linux/sunrpc/debug.h>
-#include <linux/string.h>
-#include <linux/syscalls.h>
-#include <linux/namei.h>
-#include <linux/mount.h>
-#include <linux/fs.h>
-#include <linux/nsproxy.h>
-#include <linux/pid_namespace.h>
-#include <linux/file.h>
-#include <linux/ctype.h>
-#include <linux/netdevice.h>
-#include <linux/kernel.h>
-#include <linux/uuid.h>
-#include <linux/slab.h>
-#include <linux/compat.h>
-
-static ssize_t binary_sysctl(const int *name, int nlen,
-	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
-{
-	return -ENOSYS;
-}
-
-static void deprecated_sysctl_warning(const int *name, int nlen)
-{
-	int i;
-
-	/*
-	 * CTL_KERN/KERN_VERSION is used by older glibc and cannot
-	 * ever go away.
-	 */
-	if (nlen >= 2 && name[0] == CTL_KERN && name[1] == KERN_VERSION)
-		return;
-
-	if (printk_ratelimit()) {
-		printk(KERN_INFO
-			"warning: process `%s' used the deprecated sysctl "
-			"system call with ", current->comm);
-		for (i = 0; i < nlen; i++)
-			printk(KERN_CONT "%d.", name[i]);
-		printk(KERN_CONT "\n");
-	}
-	return;
-}
-
-#define WARN_ONCE_HASH_BITS 8
-#define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS)
-
-static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE);
-
-#define FNV32_OFFSET 2166136261U
-#define FNV32_PRIME 0x01000193
-
-/*
- * Print each legacy sysctl (approximately) only once.
- * To avoid making the tables non-const use a external
- * hash-table instead.
- * Worst case hash collision: 6, but very rarely.
- * NOTE! We don't use the SMP-safe bit tests. We simply
- * don't care enough.
- */
-static void warn_on_bintable(const int *name, int nlen)
-{
-	int i;
-	u32 hash = FNV32_OFFSET;
-
-	for (i = 0; i < nlen; i++)
-		hash = (hash ^ name[i]) * FNV32_PRIME;
-	hash %= WARN_ONCE_HASH_SIZE;
-	if (__test_and_set_bit(hash, warn_once_bitmap))
-		return;
-	deprecated_sysctl_warning(name, nlen);
-}
-
-static ssize_t do_sysctl(int __user *args_name, int nlen,
-	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
-{
-	int name[CTL_MAXNAME];
-	int i;
-
-	/* Check args->nlen. */
-	if (nlen < 0 || nlen > CTL_MAXNAME)
-		return -ENOTDIR;
-	/* Read in the sysctl name for simplicity */
-	for (i = 0; i < nlen; i++)
-		if (get_user(name[i], args_name + i))
-			return -EFAULT;
-
-	warn_on_bintable(name, nlen);
-
-	return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen);
-}
-
-SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
-{
-	struct __sysctl_args tmp;
-	size_t oldlen = 0;
-	ssize_t result;
-
-	if (copy_from_user(&tmp, args, sizeof(tmp)))
-		return -EFAULT;
-
-	if (tmp.oldval && !tmp.oldlenp)
-		return -EFAULT;
-
-	if (tmp.oldlenp && get_user(oldlen, tmp.oldlenp))
-		return -EFAULT;
-
-	result = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, oldlen,
-			   tmp.newval, tmp.newlen);
-
-	if (result >= 0) {
-		oldlen = result;
-		result = 0;
-	}
-
-	if (tmp.oldlenp && put_user(oldlen, tmp.oldlenp))
-		return -EFAULT;
-
-	return result;
-}
-
-
-#ifdef CONFIG_COMPAT
-
-struct compat_sysctl_args {
-	compat_uptr_t	name;
-	int		nlen;
-	compat_uptr_t	oldval;
-	compat_uptr_t	oldlenp;
-	compat_uptr_t	newval;
-	compat_size_t	newlen;
-	compat_ulong_t	__unused[4];
-};
-
-COMPAT_SYSCALL_DEFINE1(sysctl, struct compat_sysctl_args __user *, args)
-{
-	struct compat_sysctl_args tmp;
-	compat_size_t __user *compat_oldlenp;
-	size_t oldlen = 0;
-	ssize_t result;
-
-	if (copy_from_user(&tmp, args, sizeof(tmp)))
-		return -EFAULT;
-
-	if (tmp.oldval && !tmp.oldlenp)
-		return -EFAULT;
-
-	compat_oldlenp = compat_ptr(tmp.oldlenp);
-	if (compat_oldlenp && get_user(oldlen, compat_oldlenp))
-		return -EFAULT;
-
-	result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,
-			   compat_ptr(tmp.oldval), oldlen,
-			   compat_ptr(tmp.newval), tmp.newlen);
-
-	if (result >= 0) {
-		oldlen = result;
-		result = 0;
-	}
-
-	if (compat_oldlenp && put_user(oldlen, compat_oldlenp))
-		return -EFAULT;
-
-	return result;
-}
-
-#endif /* CONFIG_COMPAT */