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From: Al Viro <viro@zeniv.linux.org.uk>
To: Carlos Neira <cneirabustos@gmail.com>
Cc: netdev@vger.kernel.org, yhs@fb.com, ebiederm@xmission.com,
	brouer@redhat.com, bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v10 2/4] bpf: new helper to obtain namespace data from  current task New bpf helper bpf_get_current_pidns_info.
Date: Fri, 6 Sep 2019 16:46:47 +0100
Message-ID: <20190906154647.GA19707@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190906152435.GW1131@ZenIV.linux.org.uk>

On Fri, Sep 06, 2019 at 04:24:35PM +0100, Al Viro wrote:
> > +	tmp = kmalloc(fnamesize, GFP_ATOMIC);
> > +	if (unlikely(!tmp)) {
> > +		__putname(fname);
> > +		ret = -ENOMEM;
> > +		goto clear;
> > +	}
> > +
> > +	tmp->name = (char *)fname;
> > +	fname = tmp;
> > +	len = strlen(pidns_path) + 1;
> > +	memcpy((char *)fname->name, pidns_path, len);
> > +	fname->uptr = NULL;
> > +	fname->aname = NULL;
> > +	fname->refcnt = 1;
> > +
> > +	ret = filename_lookup(AT_FDCWD, fname, 0, &kp, NULL);
> > +	if (ret)
> > +		goto clear;
> 
> Where do I begin?
> 	* getname_kernel() is there for purpose
> 	* so's kern_path(), damnit

Oh, and filename_lookup() *CAN* sleep, obviously.  So that
GFP_ATOMIC above is completely pointless.

> > +
> > +	inode = d_backing_inode(kp.dentry);
> > +	pidns_info->dev = (u32)inode->i_rdev;

Why are plaing with device number, anyway?  And why would it
be anything other than 0?

  reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-06 15:09 [PATCH bpf-next v10 0/4] BPF: New helper to obtain namespace data from current task Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 1/4] fs/namei.c: make available filename_lookup() for bpf helpers Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 2/4] bpf: new helper to obtain namespace data from current task New bpf helper bpf_get_current_pidns_info Carlos Neira
2019-09-06 15:24   ` Al Viro
2019-09-06 15:46     ` Al Viro [this message]
2019-09-06 16:00       ` Al Viro
2019-09-06 23:21         ` Yonghong Song
2019-09-07  0:10           ` Al Viro
2019-09-07  6:34             ` Yonghong Song
2019-09-09 17:45               ` Carlos Antonio Neira Bustos
2019-09-10 22:35                 ` Yonghong Song
2019-09-10 23:15                   ` Al Viro
2019-09-11  8:16                     ` Eric W. Biederman
2019-09-12  5:49                       ` Yonghong Song
     [not found]                         ` <CACiB22j9M2gmccnh7XqqFp8g7qKFuiOrSAVJiA2tQHLB0pmoSQ@mail.gmail.com>
2019-09-13  2:56                           ` Yonghong Song
2019-09-13 11:58                             ` Carlos Antonio Neira Bustos
2019-09-13 16:59                         ` Eric W. Biederman
2019-09-13 17:28                           ` Yonghong Song
2019-09-11  4:32                   ` Carlos Antonio Neira Bustos
2019-09-11  8:17                     ` Eric W. Biederman
2019-09-10 22:46   ` Yonghong Song
2019-09-11  4:33     ` Carlos Antonio Neira Bustos
2019-09-06 15:09 ` [PATCH bpf-next v10 3/4] tools: Added bpf_get_current_pidns_info helper Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 4/4] tools/testing/selftests/bpf: Add self-tests for helper bpf_get_pidns_info Carlos Neira
2019-09-10 22:55   ` Yonghong Song

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