lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sat, 20 Feb 2021 16:45:40 -0800 From: Linus Torvalds <torvalds@...ux-foundation.org> To: Al Viro <viro@...iv.linux.org.uk> Cc: syzbot <syzbot+3d2c27c2b7dc2a94814d@...kaller.appspotmail.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jiri Slaby <jirislaby@...nel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, snovitoll@...il.com, syzkaller-bugs <syzkaller-bugs@...glegroups.com> Subject: Re: WARNING in iov_iter_revert (2) [ Let's see how long this lasts, but I've got a generator for the laptop, and hopefully I'll be able to start doing pulls tonight, and get "real" power tomorrow ] On Sat, Feb 20, 2021 at 11:30 AM Al Viro <viro@...iv.linux.org.uk> wrote: > > IOW, it's not iov_iter_revert() being weird or do_tty_write() misuing it - > it's tpk_write() playing silly buggers. Ok, that's actually not as bad I was was afraid it might be. > Do we want to preserve that weirdness of /dev/ttyprintk writes? > That's orthogonal to the iov_iter uses in there. I don't think the ttyprintk weirdness was intentional. I'd fix that, but in the meantime clearly we should make do_tty_write() protect against this insanity, and do something like --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -961,6 +961,9 @@ static inline ssize_t do_tty_write( ret = write(tty, file, tty->write_buf, size); if (ret <= 0) break; + /* ttyprintk historical oddity */ + if (ret > size) + break; /* FIXME! Have Al check this! */ if (ret != size) in there. Because right now we clearly do strange and not-so-wonderful things if the write routine returns a bigger value than it was passed.. Not limited to that iov_iter_revert() thing, but the whole loop. Comments? Linus
Powered by blists - more mailing lists