• Cyrill Gorcunov's avatar
    sunrpc: fix possible overrun on read of /proc/sys/sunrpc/transports · 27df6f25
    Cyrill Gorcunov authored
    Vegard Nossum reported
    > I noticed that something weird is going on with /proc/sys/sunrpc/transports.
    > This file is generated in net/sunrpc/sysctl.c, function proc_do_xprt(). When
    > I "cat" this file, I get the expected output:
    >    $ cat /proc/sys/sunrpc/transports
    >    tcp 1048576
    >    udp 32768
    > But I think that it does not check the length of the buffer supplied by
    > userspace to read(). With my original program, I found that the stack was
    > being overwritten by the characters above, even when the length given to
    > read() was just 1.
    David Wagner added (among other things) that copy_to_user could be
    probably used here.
    Ingo Oeser suggested to use simple_read_from_buffer() here.
    The conclusion is that proc_do_xprt doesn't check for userside buffer
    size indeed so fix this by using Ingo's suggestion.
    Reported-by: default avatarVegard Nossum <vegard.nossum@gmail.com>
    Signed-off-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
    CC: Ingo Oeser <ioe-lkml@rameria.de>
    Cc: Neil Brown <neilb@suse.de>
    Cc: Chuck Lever <chuck.lever@oracle.com>
    Cc: Greg Banks <gnb@sgi.com>
    Cc: Tom Tucker <tom@opengridcomputing.com>
    Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
sysctl.c 3.62 KB