Am 21.04.2016 um 18:28 hat Peter Maydell geschrieben: > On 21 April 2016 at 15:42, Eric Blake <ebl...@redhat.com> wrote: > > The NBD protocol does not (yet) force any alignment constraints > > on clients. Even though qemu NBD clients always send requests > > that are aligned to 512 bytes, we must be prepared for non-qemu > > clients that don't care about alignment (even if it means they > > are less efficient). Our use of blk_read() and blk_write() was > > silently operating on the wrong file offsets when the client > > made an unaligned request, corrupting the client's data (but > > as the client already has control over the file we are serving, > > I don't think it is a security hole, per se, just a data > > corruption bug). > > > > Note that in the case of NBD_CMD_READ, an unaligned length could > > cause us to return up to 511 bytes of uninitialized trailing > > garbage from blk_try_blockalign() - hopefully nothing sensitive > > from the heap's prior usage is ever leaked in that manner. > > > > Signed-off-by: Eric Blake <ebl...@redhat.com> > > --- > > > > It's late for 2.6, but as a data corruption bug fix, I think > > it's worth having if there is still time. > > I want to tag rc3 today, but since it looks like there's going to > be an rc4 for the virtio handler bug this can probably go into rc4 > if it gets review.
Reviewed-by: Kevin Wolf <kw...@redhat.com> Peter, do you want a pull request (which I would have to do because Paolo is away) or are you going to apply the patch directly? Also adding Cc: qemu-stable, because this is an old bug that has existed ever since qemu-nbd was added. Kevin
