• Eric Dumazet's avatar
    scm: add user copy checks to put_cmsg() · 5f1eb1ff
    Eric Dumazet authored
    This is a followup of commit 2558b803 ("net: use a bounce
    buffer for copying skb->mark")
    
    x86 and powerpc define user_access_begin, meaning
    that they are not able to perform user copy checks
    when using user_write_access_begin() / unsafe_copy_to_user()
    and friends [1]
    
    Instead of waiting bugs to trigger on other arches,
    add a check_object_size() in put_cmsg() to make sure
    that new code tested on x86 with CONFIG_HARDENED_USERCOPY=y
    will perform more security checks.
    
    [1] We can not generically call check_object_size() from
    unsafe_copy_to_user() because UACCESS is enabled at this point.
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Cc: Kees Cook <keescook@chromium.org>
    Acked-by: default avatarKees Cook <keescook@chromium.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    5f1eb1ff
scm.c 8.53 KB