Messages in this thread Patch in this message | | | From | Xiaoming Ni <> | Subject | [PATCH] sysctl: Delete the code of sys_sysctl | Date | Tue, 9 Jun 2020 14:20:05 +0800 |
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Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"), sys_sysctl has lost its actual role: any input can only return an error.
Delete the code and return -ENOSYS directly at the function entry
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> --- kernel/sysctl_binary.c | 146 +------------------------------------------------ 1 file changed, 2 insertions(+), 144 deletions(-)
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c index 7d550cc..41a88f8 100644 --- a/kernel/sysctl_binary.c +++ b/kernel/sysctl_binary.c @@ -1,126 +1,11 @@ // 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; + return -ENOSYS; } @@ -138,34 +23,7 @@ struct compat_sysctl_args { 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; + return -ENOSYS; } #endif /* CONFIG_COMPAT */ -- 1.8.5.6
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