fs/ext4/xattr_security.c

   1 /*
   2  * linux/fs/ext4/xattr_security.c
   3  * Handler for storing security labels as extended attributes.
   4  */
   5
   6 #include <linux/string.h>
   7 #include <linux/fs.h>
   8 #include <linux/security.h>
   9 #include <linux/slab.h>
  10 #include "ext4_jbd2.h"
  11 #include "ext4.h"
  12 #include "xattr.h"
  13
  14 static size_t
  15 ext4_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
  16                 const char *name, size_t name_len, int type)
  17 {
  18         const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
  19         const size_t total_len = prefix_len + name_len + 1;
  20
  21
  22         if (list && total_len <= list_size) {
  23                 memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
  24                 memcpy(list+prefix_len, name, name_len);
  25                 list[prefix_len + name_len] = '\0';
  26         }
  27         return total_len;
  28 }
  29
  30 static int
  31 ext4_xattr_security_get(struct dentry *dentry, const char *name,
  32                        void *buffer, size_t size, int type)
  33 {
  34         if (strcmp(name, "") == 0)
  35                 return -EINVAL;
  36         return ext4_xattr_get(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
  37                               name, buffer, size);
  38 }
  39
  40 static int
  41 ext4_xattr_security_set(struct dentry *dentry, const char *name,
  42                 const void *value, size_t size, int flags, int type)
  43 {
  44         if (strcmp(name, "") == 0)
  45                 return -EINVAL;
  46         return ext4_xattr_set(d_inode(dentry), EXT4_XATTR_INDEX_SECURITY,
  47                               name, value, size, flags);
  48 }
  49
  50 static int
  51 ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
  52                 void *fs_info)
  53 {
  54         const struct xattr *xattr;
  55         handle_t *handle = fs_info;
  56         int err = 0;
  57
  58         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
  59                 err = ext4_xattr_set_handle(handle, inode,
  60                                             EXT4_XATTR_INDEX_SECURITY,
  61                                             xattr->name, xattr->value,
  62                                             xattr->value_len, 0);
  63                 if (err < 0)
  64                         break;
  65         }
  66         return err;
  67 }
  68
  69 int
  70 ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
  71                    const struct qstr *qstr)
  72 {
  73         return security_inode_init_security(inode, dir, qstr,
  74                                             &ext4_initxattrs, handle);
  75 }
  76
  77 const struct xattr_handler ext4_xattr_security_handler = {
  78         .prefix = XATTR_SECURITY_PREFIX,
  79         .list   = ext4_xattr_security_list,
  80         .get    = ext4_xattr_security_get,
  81         .set    = ext4_xattr_security_set,
  82 };