]> www.infradead.org Git - users/jedix/linux-maple.git/commitdiff
nbd: don't allow invalid blocksize settings
authorJens Axboe <axboe@kernel.dk>
Tue, 4 Sep 2018 17:52:34 +0000 (11:52 -0600)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 19 Sep 2018 20:43:35 +0000 (22:43 +0200)
commit bc811f05d77f47059c197a98b6ad242eb03999cb upstream.

syzbot reports a divide-by-zero off the NBD_SET_BLKSIZE ioctl.
We need proper validation of the input here. Not just if it's
zero, but also if the value is a power-of-2 and in a valid
range. Add that.

Cc: stable@vger.kernel.org
Reported-by: syzbot <syzbot+25dbecbec1e62c6b0dd4@syzkaller.appspotmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/block/nbd.c

index 5e55d03d3d011f5d177f09a13d98fd631dac2551..fe1414df0f3319cb201eb9fb63b14c4773c1c3fa 100644 (file)
@@ -1228,6 +1228,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
        case NBD_SET_SOCK:
                return nbd_add_socket(nbd, arg, false);
        case NBD_SET_BLKSIZE:
+               if (!arg || !is_power_of_2(arg) || arg < 512 ||
+                   arg > PAGE_SIZE)
+                       return -EINVAL;
                nbd_size_set(nbd, arg,
                             div_s64(config->bytesize, arg));
                return 0;