lkml.org 
[lkml]   [2020]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 20/86] ALSA: info: Drop WARN_ON() from buffer NULL sanity check
    Date
    From: Takashi Iwai <tiwai@suse.de>

    commit 60379ba08532eca861e933b389526a4dc89e0c42 upstream.

    snd_info_get_line() has a sanity check of NULL buffer -- both buffer
    itself being NULL and buffer->buffer being NULL. Basically both
    checks are valid and necessary, but the problem is that it's with
    snd_BUG_ON() macro that triggers WARN_ON(). The latter condition
    (NULL buffer->buffer) can be met arbitrarily by user since the buffer
    is allocated at the first write, so it means that user can trigger
    WARN_ON() at will.

    This patch addresses it by simply moving buffer->buffer NULL check out
    of snd_BUG_ON() so that spurious WARNING is no longer triggered.

    Reported-by: syzbot+e42d0746c3c3699b6061@syzkaller.appspotmail.com
    Cc: <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/20200717084023.5928-1-tiwai@suse.de
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    sound/core/info.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    --- a/sound/core/info.c
    +++ b/sound/core/info.c
    @@ -634,7 +634,9 @@ int snd_info_get_line(struct snd_info_bu
    {
    int c = -1;

    - if (snd_BUG_ON(!buffer || !buffer->buffer))
    + if (snd_BUG_ON(!buffer))
    + return 1;
    + if (!buffer->buffer)
    return 1;
    if (len <= 0 || buffer->stop || buffer->error)
    return 1;

    \
     
     \ /
      Last update: 2020-07-27 16:40    [W:4.032 / U:0.484 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site