Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Theodore Ts'o
On Thu, Sep 22, 2016 at 04:21:30PM +0200, Richard Weinberger wrote: > > Got it. So, the use case is preventing off-line attacks. > But I fear this is only a drop in the bucket. What we really need is > meta data authentication. True security requires a system-wide design, sure. For example, you

Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Theodore Ts'o
On Thu, Sep 22, 2016 at 04:21:30PM +0200, Richard Weinberger wrote: > > Got it. So, the use case is preventing off-line attacks. > But I fear this is only a drop in the bucket. What we really need is > meta data authentication. True security requires a system-wide design, sure. For example, you

Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Richard Weinberger
Ted, On 22.09.2016 15:44, Theodore Ts'o wrote: > On Thu, Sep 22, 2016 at 02:24:35PM +0200, Richard Weinberger wrote: >> Why do we need this check? AFAIK this situation can never happen unless due >> to >> a bug in the filesystem code. > > Or in the case of a malicious attacker who is trying to

Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Richard Weinberger
Ted, On 22.09.2016 15:44, Theodore Ts'o wrote: > On Thu, Sep 22, 2016 at 02:24:35PM +0200, Richard Weinberger wrote: >> Why do we need this check? AFAIK this situation can never happen unless due >> to >> a bug in the filesystem code. > > Or in the case of a malicious attacker who is trying to

Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Theodore Ts'o
On Thu, Sep 22, 2016 at 02:24:35PM +0200, Richard Weinberger wrote: > Hi! > > Both ext4 and f2fs check in the file open code the context of the parent > directory too: > > ext4: > if (ext4_encrypted_inode(d_inode(dir)) && >

Re: ext4, f2fs: fscrypt_has_permitted_context() check in file open

2016-09-22 Thread Theodore Ts'o
On Thu, Sep 22, 2016 at 02:24:35PM +0200, Richard Weinberger wrote: > Hi! > > Both ext4 and f2fs check in the file open code the context of the parent > directory too: > > ext4: > if (ext4_encrypted_inode(d_inode(dir)) && >