• John Fastabend's avatar
    bpf: Sockmap/tls, fix pop data with SK_DROP return code · 7361d448
    John Fastabend authored
    When user returns SK_DROP we need to reset the number of copied bytes
    to indicate to the user the bytes were dropped and not sent. If we
    don't reset the copied arg sendmsg will return as if those bytes were
    copied giving the user a positive return value.
    
    This works as expected today except in the case where the user also
    pops bytes. In the pop case the sg.size is reduced but we don't correctly
    account for this when copied bytes is reset. The popped bytes are not
    accounted for and we return a small positive value potentially confusing
    the user.
    
    The reason this happens is due to a typo where we do the wrong comparison
    when accounting for pop bytes. In this fix notice the if/else is not
    needed and that we have a similar problem if we push data except its not
    visible to the user because if delta is larger the sg.size we return a
    negative value so it appears as an error regardless.
    
    Fixes: 7246d8ed ("bpf: helper to pop data from messages")
    Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
    Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
    Acked-by: default avatarJonathan Lemon <jonathan.lemon@gmail.com>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/bpf/20200111061206.8028-9-john.fastabend@gmail.com
    7361d448
tls_sw.c 61.3 KB