• Alan Stern's avatar
    USB: yurex: Don't retry on unexpected errors · a8fe336f
    Alan Stern authored
    commit 32a0721c upstream.
    
    According to Greg KH, it has been generally agreed that when a USB
    driver encounters an unknown error (or one it can't handle directly),
    it should just give up instead of going into a potentially infinite
    retry loop.
    
    The three codes -EPROTO, -EILSEQ, and -ETIME fall into this category.
    They can be caused by bus errors such as packet loss or corruption,
    attempting to communicate with a disconnected device, or by malicious
    firmware.  Nowadays the extent of packet loss or corruption is
    negligible, so it should be safe for a driver to give up whenever one
    of these errors occurs.
    
    Although the yurex driver handles -EILSEQ errors in this way, it
    doesn't do the same for -EPROTO (as discovered by the syzbot fuzzer)
    or other unrecognized errors.  This patch adjusts the driver so that
    it doesn't log an error message for -EPROTO or -ETIME, and it doesn't
    retry after any errors.
    
    Reported-and-tested-by: syzbot+b24d736f18a1541ad550@syzkaller.appspotmail.com
    Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
    CC: Tomoki Sekiyama <tomoki.sekiyama@gmail.com>
    CC: <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1909171245410.1590-100000@iolanthe.rowland.orgSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    a8fe336f
yurex.c 12.6 KB