kernel/sysctl_binary.c

   1 #include <linux/stat.h>
   2 #include <linux/sysctl.h>
   3 #include "../fs/xfs/linux-2.6/xfs_sysctl.h"
   4 #include <linux/sunrpc/debug.h>
   5 #include <linux/string.h>
   6 #include <net/ip_vs.h>
   7 #include <linux/syscalls.h>
   8 #include <linux/namei.h>
   9 #include <linux/mount.h>
  10 #include <linux/fs.h>
  11 #include <linux/nsproxy.h>
  12 #include <linux/pid_namespace.h>
  13 #include <linux/file.h>
  14 #include <linux/ctype.h>
  15 #include <linux/smp_lock.h>
  16
  17 #ifdef CONFIG_SYSCTL_SYSCALL
  18
  19 /* Perform the actual read/write of a sysctl table entry. */
  20 static int do_sysctl_strategy(struct ctl_table_root *root,
  21                         struct ctl_table *table,
  22                         void __user *oldval, size_t __user *oldlenp,
  23                         void __user *newval, size_t newlen)
  24 {
  25         int op = 0, rc;
  26
  27         if (oldval)
  28                 op |= MAY_READ;
  29         if (newval)
  30                 op |= MAY_WRITE;
  31         if (sysctl_perm(root, table, op))
  32                 return -EPERM;
  33
  34         if (table->strategy) {
  35                 rc = table->strategy(table, oldval, oldlenp, newval, newlen);
  36                 if (rc < 0)
  37                         return rc;
  38                 if (rc > 0)
  39                         return 0;
  40         }
  41
  42         /* If there is no strategy routine, or if the strategy returns
  43          * zero, proceed with automatic r/w */
  44         if (table->data && table->maxlen) {
  45                 rc = sysctl_data(table, oldval, oldlenp, newval, newlen);
  46                 if (rc < 0)
  47                         return rc;
  48         }
  49         return 0;
  50 }
  51
  52 static int parse_table(const int *name, int nlen,
  53                        void __user *oldval, size_t __user *oldlenp,
  54                        void __user *newval, size_t newlen,
  55                        struct ctl_table_root *root,
  56                        struct ctl_table *table)
  57 {
  58         int n;
  59 repeat:
  60         if (!nlen)
  61                 return -ENOTDIR;
  62         n = *name;
  63         for ( ; table->ctl_name || table->procname; table++) {
  64                 if (!table->ctl_name)
  65                         continue;
  66                 if (n == table->ctl_name) {
  67                         int error;
  68                         if (table->child) {
  69                                 if (sysctl_perm(root, table, MAY_EXEC))
  70                                         return -EPERM;
  71                                 name++;
  72                                 nlen--;
  73                                 table = table->child;
  74                                 goto repeat;
  75                         }
  76                         error = do_sysctl_strategy(root, table,
  77                                                    oldval, oldlenp,
  78                                                    newval, newlen);
  79                         return error;
  80                 }
  81         }
  82         return -ENOTDIR;
  83 }
  84
  85 static ssize_t binary_sysctl(const int *name, int nlen,
  86         void __user *oldval, size_t __user *oldlenp,
  87         void __user *newval, size_t newlen)
  88
  89 {
  90         struct ctl_table_header *head;
  91         ssize_t error = -ENOTDIR;
  92
  93         for (head = sysctl_head_next(NULL); head;
  94                         head = sysctl_head_next(head)) {
  95                 error = parse_table(name, nlen, oldval, oldlenp,
  96                                         newval, newlen,
  97                                         head->root, head->ctl_table);
  98                 if (error != -ENOTDIR) {
  99                         sysctl_head_finish(head);
 100                         break;
 101                 }
 102         }
 103         return error;
 104 }
 105
 106 #else /* CONFIG_SYSCTL_SYSCALL */
 107
 108 static ssize_t binary_sysctl(const int *ctl_name, int nlen,
 109         void __user *oldval, size_t __user *oldlenp,
 110         void __user *newval, size_t newlen)
 111 {
 112         return -ENOSYS;
 113 }
 114
 115 #endif /* CONFIG_SYSCTL_SYSCALL */
 116
 117 static void deprecated_sysctl_warning(const int *name, int nlen)
 118 {
 119         static int msg_count;
 120         int i;
 121
 122         /* Ignore accesses to kernel.version */
 123         if ((nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
 124                 return;
 125
 126         if (msg_count < 5) {
 127                 msg_count++;
 128                 printk(KERN_INFO
 129                         "warning: process `%s' used the deprecated sysctl "
 130                         "system call with ", current->comm);
 131                 for (i = 0; i < nlen; i++)
 132                         printk("%d.", name[i]);
 133                 printk("\n");
 134         }
 135         return;
 136 }
 137
 138 int do_sysctl(int __user *args_name, int nlen,
 139         void __user *oldval, size_t __user *oldlenp,
 140         void __user *newval, size_t newlen)
 141 {
 142         int name[CTL_MAXNAME];
 143         size_t oldlen = 0;
 144         int i;
 145
 146         if (nlen <= 0 || nlen >= CTL_MAXNAME)
 147                 return -ENOTDIR;
 148         if (oldval && !oldlenp)
 149                 return -EFAULT;
 150         if (oldlenp && get_user(oldlen, oldlenp))
 151                 return -EFAULT;
 152
 153         /* Read in the sysctl name for simplicity */
 154         for (i = 0; i < nlen; i++)
 155                 if (get_user(name[i], args_name + i))
 156                         return -EFAULT;
 157
 158         deprecated_sysctl_warning(name, nlen);
 159
 160         return binary_sysctl(name, nlen, oldval, oldlenp, newval, newlen);
 161 }
 162
 163
 164 SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
 165 {
 166         struct __sysctl_args tmp;
 167         int error;
 168
 169         if (copy_from_user(&tmp, args, sizeof(tmp)))
 170                 return -EFAULT;
 171
 172         lock_kernel();
 173         error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
 174                           tmp.newval, tmp.newlen);
 175         unlock_kernel();
 176
 177         return error;
 178 }