kernel/sysctl_check.c

   1 #include <linux/stat.h>
   2 #include <linux/sysctl.h>
   3 #include "../fs/xfs/xfs_sysctl.h"
   4 #include <linux/sunrpc/debug.h>
   5 #include <linux/string.h>
   6 #include <net/ip_vs.h>
   7
   8
   9 static int sysctl_depth(struct ctl_table *table)
  10 {
  11         struct ctl_table *tmp;
  12         int depth;
  13
  14         depth = 0;
  15         for (tmp = table; tmp->parent; tmp = tmp->parent)
  16                 depth++;
  17
  18         return depth;
  19 }
  20
  21 static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
  22 {
  23         int i;
  24
  25         for (i = 0; table && i < n; i++)
  26                 table = table->parent;
  27
  28         return table;
  29 }
  30
  31
  32 static void sysctl_print_path(struct ctl_table *table)
  33 {
  34         struct ctl_table *tmp;
  35         int depth, i;
  36         depth = sysctl_depth(table);
  37         if (table->procname) {
  38                 for (i = depth; i >= 0; i--) {
  39                         tmp = sysctl_parent(table, i);
  40                         printk("/%s", tmp->procname?tmp->procname:"");
  41                 }
  42         }
  43         printk(" ");
  44 }
  45
  46 static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
  47                                                 struct ctl_table *table)
  48 {
  49         struct ctl_table_header *head;
  50         struct ctl_table *ref, *test;
  51         int depth, cur_depth;
  52
  53         depth = sysctl_depth(table);
  54
  55         for (head = __sysctl_head_next(namespaces, NULL); head;
  56              head = __sysctl_head_next(namespaces, head)) {
  57                 cur_depth = depth;
  58                 ref = head->ctl_table;
  59 repeat:
  60                 test = sysctl_parent(table, cur_depth);
  61                 for (; ref->procname; ref++) {
  62                         int match = 0;
  63                         if (cur_depth && !ref->child)
  64                                 continue;
  65
  66                         if (test->procname && ref->procname &&
  67                             (strcmp(test->procname, ref->procname) == 0))
  68                                         match++;
  69
  70                         if (match) {
  71                                 if (cur_depth != 0) {
  72                                         cur_depth--;
  73                                         ref = ref->child;
  74                                         goto repeat;
  75                                 }
  76                                 goto out;
  77                         }
  78                 }
  79         }
  80         ref = NULL;
  81 out:
  82         sysctl_head_finish(head);
  83         return ref;
  84 }
  85
  86 static void set_fail(const char **fail, struct ctl_table *table, const char *str)
  87 {
  88         if (*fail) {
  89                 printk(KERN_ERR "sysctl table check failed: ");
  90                 sysctl_print_path(table);
  91                 printk(" %s\n", *fail);
  92                 dump_stack();
  93         }
  94         *fail = str;
  95 }
  96
  97 static void sysctl_check_leaf(struct nsproxy *namespaces,
  98                                 struct ctl_table *table, const char **fail)
  99 {
 100         struct ctl_table *ref;
 101
 102         ref = sysctl_check_lookup(namespaces, table);
 103         if (ref && (ref != table))
 104                 set_fail(fail, table, "Sysctl already exists");
 105 }
 106
 107 int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
 108 {
 109         int error = 0;
 110         for (; table->procname; table++) {
 111                 const char *fail = NULL;
 112
 113                 if (table->parent) {
 114                         if (!table->parent->procname)
 115                                 set_fail(&fail, table, "Parent without procname");
 116                 }
 117                 if (table->child) {
 118                         if (table->data)
 119                                 set_fail(&fail, table, "Directory with data?");
 120                         if (table->maxlen)
 121                                 set_fail(&fail, table, "Directory with maxlen?");
 122                         if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
 123                                 set_fail(&fail, table, "Writable sysctl directory");
 124                         if (table->proc_handler)
 125                                 set_fail(&fail, table, "Directory with proc_handler");
 126                         if (table->extra1)
 127                                 set_fail(&fail, table, "Directory with extra1");
 128                         if (table->extra2)
 129                                 set_fail(&fail, table, "Directory with extra2");
 130                 } else {
 131                         if ((table->proc_handler == proc_dostring) ||
 132                             (table->proc_handler == proc_dointvec) ||
 133                             (table->proc_handler == proc_dointvec_minmax) ||
 134                             (table->proc_handler == proc_dointvec_jiffies) ||
 135                             (table->proc_handler == proc_dointvec_userhz_jiffies) ||
 136                             (table->proc_handler == proc_dointvec_ms_jiffies) ||
 137                             (table->proc_handler == proc_doulongvec_minmax) ||
 138                             (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
 139                                 if (!table->data)
 140                                         set_fail(&fail, table, "No data");
 141                                 if (!table->maxlen)
 142                                         set_fail(&fail, table, "No maxlen");
 143                         }
 144 #ifdef CONFIG_PROC_SYSCTL
 145                         if (!table->proc_handler)
 146                                 set_fail(&fail, table, "No proc_handler");
 147 #endif
 148                         sysctl_check_leaf(namespaces, table, &fail);
 149                 }
 150                 if (table->mode > 0777)
 151                         set_fail(&fail, table, "bogus .mode");
 152                 if (fail) {
 153                         set_fail(&fail, table, NULL);
 154                         error = -EINVAL;
 155                 }
 156                 if (table->child)
 157                         error |= sysctl_check_table(namespaces, table->child);
 158         }
 159         return error;
 160 }