Hi Ted, Jaegeuk, On 2016/8/28 14:16, Chao Yu wrote: > Hi Ted, > > On 2016/8/28 13:13, Theodore Ts'o wrote: >> On Sun, Aug 28, 2016 at 09:13:28AM +0800, Chao Yu wrote: >>> From: Chao Yu <yuchao0@xxxxxxxxxx> >>> >>> This patch fixes to add null character at the end of encrypted filename Since encryption functionality in ext4/f2fs was exported to vfs as fscrypot module, more filesystems can use it, I'm not sure, maybe other fs will traverse encrypted filename directly. So, could we set this null character in fname_encrypt in advance in order to avoid hitting random characters behind target filename when traversing it? Thanks, >>> in fname_encrypt, in order to avoid incorrectly traversing random data >>> located after target filename. The call stack is as below: >>> >>> - f2fs_add_link >>> - __f2fs_add_link >>> - fscrypt_setup_filename >>> - fscrypt_fname_alloc_buffer allocate buffer for @fname >>> - fname_encrypt didn't set null character for @fname >>> - f2fs_add_regular_entry init qstr with @fname >>> - init_inode_metadata >>> - f2fs_init_security >>> - security_inode_init_security >>> - selinux_inode_init_security >>> - selinux_determine_inode_label >>> - security_transition_sid >>> - security_compute_sid >>> - filename_compute_type >>> - hashtab_search >>> - filenametr_hash traverse @fname as one which has null character >> >> The problem is not in fname_encrypt(), but rather that >> security_inode_init_security() should be given the _unencrypted_ >> filename. >> >> In ext4 security_inode_init_security() is called with the qstr from >> the dentry, not the encrypted qstr --- in fact we call >> security_inode_init_security before we call fname_encrypt. >> >> SELinux needs the unencrypted filename in order to decide which >> SELinux rules / labels should apply. > > You're right, I missed this mistake. So actually, this is a bug of f2fs. > Let me figure out the fixing patch. > > Thanks for your review! :) > > Thanks, > >> >> - Ted >> > > ------------------------------------------------------------------------------ > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
