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/ext4_jbd2.h> 10 #include <linux/ext4_fs.h> 11 #include <linux/security.h> 12 #include "xattr.h" 13 14 static size_t 15 ext4_xattr_security_list(struct inode *inode, char *list, size_t list_size, 16 const char *name, size_t name_len) 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 inode *inode, const char *name, 32 void *buffer, size_t size) 33 { 34 if (strcmp(name, "") == 0) 35 return -EINVAL; 36 return ext4_xattr_get(inode, EXT4_XATTR_INDEX_SECURITY, name, 37 buffer, size); 38 } 39 40 static int 41 ext4_xattr_security_set(struct inode *inode, const char *name, 42 const void *value, size_t size, int flags) 43 { 44 if (strcmp(name, "") == 0) 45 return -EINVAL; 46 return ext4_xattr_set(inode, EXT4_XATTR_INDEX_SECURITY, name, 47 value, size, flags); 48 } 49 50 int 51 ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir) 52 { 53 int err; 54 size_t len; 55 void *value; 56 char *name; 57 58 err = security_inode_init_security(inode, dir, &name, &value, &len); 59 if (err) { 60 if (err == -EOPNOTSUPP) 61 return 0; 62 return err; 63 } 64 err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY, 65 name, value, len, 0); 66 kfree(name); 67 kfree(value); 68 return err; 69 } 70 71 struct xattr_handler ext4_xattr_security_handler = { 72 .prefix = XATTR_SECURITY_PREFIX, 73 .list = ext4_xattr_security_list, 74 .get = ext4_xattr_security_get, 75 .set = ext4_xattr_security_set, 76 }; 77