Messages in this thread | | | From | Pietro Borrello <> | Date | Wed, 1 Feb 2023 12:01:12 +0100 | Subject | Re: [PATCH net-next 1/2] tun: tun_chr_open(): correctly initialize socket uid |
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On Wed, 1 Feb 2023 at 04:10, Stephen Hemminger <stephen@networkplumber.org> wrote: > > On Wed, 01 Feb 2023 00:35:45 +0000 > Pietro Borrello <borrello@diag.uniroma1.it> wrote: > > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > > index a7d17c680f4a..6713fffb1488 100644 > > --- a/drivers/net/tun.c > > +++ b/drivers/net/tun.c > > @@ -3450,6 +3450,11 @@ static int tun_chr_open(struct inode *inode, struct file * file) > > > > sock_init_data(&tfile->socket, &tfile->sk); > > > > + // sock_init_data initializes sk.sk_uid assuming tfile->socket is embedded > > + // in a struct socket_alloc and reading its corresponding inode. Since we > > + // pass a socket contained in a struct tun_file we have to fix this manually > > + tfile->sk.sk_uid = inode->i_uid; > > + > > Do not use C++ style comments in the kernel.
Thanks for pointing it out. I will fix this in v2.
> Rule #1 of code maintenance. Bug fixes should not stand out.
Thanks for the comment. I agree bug fixes should not stand out. I sent the patches also to sparkle some discussion on how this should be better fixed. As briefly mentioned in the cover letter, I am not sure what is the cleanest fix according to Linux standards. Are you suggesting a briefer comment or removing it completely?
The alternative fixes I see, would be: 1) pass a NULL socket and manually initialize it, which I think would make the fix to stand out more, but it would be probably cleaner 2) change the API of sock_init_data, but probably not worth it, given tuntap devices are the only 2 users among almost 60 to break the socket_alloc assumption 3) introduce a sock_init_data_with_inode which explicitly uses an inode to initialize uid, but would be a bad solution for code duplication 4) wrap sock_init_data call to fix uid in a similar fashion as done here, maybe cleaner
Best regards, Pietro
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