Messages in this thread | | | Subject | Re: [PATCH] fscrypto: fix to null-terminate encrypted filename in fname_encrypt | From | Chao Yu <> | Date | Sun, 28 Aug 2016 14:16:03 +0800 |
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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@huawei.com> >> >> This patch fixes to add null character at the end of encrypted filename >> 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 >
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