Messages in this thread | | | Date | Fri, 5 Oct 2018 05:46:59 +0100 | From | Al Viro <> | Subject | Re: [PATCH bpf-next 1/6] bpf: introduce BPF_PROG_TYPE_FILE_FILTER |
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On Wed, Oct 03, 2018 at 07:57:45PM -0700, Alexei Starovoitov wrote:
> @@ -15,6 +15,7 @@ > #include <linux/bpf.h> > #include <linux/bpf-cgroup.h> > #include <net/sock.h> > +#include <../fs/mount.h>
No.
> + struct file *file = NULL; > + struct inode *inode; > + struct super_block *sb; > + struct mount *mnt;
Fuck, no.
> + case offsetof(struct bpf_file_info, mnt_id): > + /* dst = real_mount(file->f_path.mnt)->mnt_id */ > + mnt = real_mount(LD_1(file->f_path.mnt)); > + LD_n(mnt->mnt_id);
NAK. Anything in struct mount is private to just a couple of files in fs/*.c. Don't do that. And keep in mind that internal details can and will be changed at zero notice, so be careful with adding such stuff.
Another problem is your direct poking in ->i_ino. It's not something directly exposed to userland at the moment and it should not become such. Filesystem has every right to have ->getattr() set ->ino (== ->st_ino value) in whichever way it likes; the same goes for ->dev.
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