Eric Blake df7b97ff89 nbd: Don't mishandle unaligned client requests ... 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 <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Tested-by: Kevin Wolf <kwolf@redhat.com> Message-id: 1461249750-31928-1-git-send-email-eblake@redhat.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>		2016-04-22 11:55:35 +01:00
..
client.c	nbd: Don't fail handshake on NBD_OPT_LIST descriptions	2016-04-15 17:56:56 +02:00
common.c	nbd: do not hang nbd_wr_syncv if outside a coroutine and no available data	2016-04-08 00:07:44 +02:00
Makefile.objs	nbd: Split nbd.c	2016-01-15 18:58:02 +01:00
nbd-internal.h	nbd: Avoid bitrot in TRACE() usage	2016-04-08 00:07:43 +02:00
server.c	nbd: Don't mishandle unaligned client requests	2016-04-22 11:55:35 +01:00