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