diff options
| author | Jan Beulich <jbeulich@suse.com> | 2017-06-13 23:28:27 +0300 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2017-06-13 23:28:32 +0300 |
| commit | 089bc0143f489bd3a4578bdff5f4ca68fb26f341 (patch) | |
| tree | cacf9b2c4a98d97f7b697537fbbcd0909eb7ff1f /drivers/block/xen-blkback/blkback.c | |
| parent | a24fa22ce22ae302b3bf8f7008896d52d5d57b8d (diff) | |
| download | linux-089bc0143f489bd3a4578bdff5f4ca68fb26f341.tar.xz | |
xen-blkback: don't leak stack data via response ring
Rather than constructing a local structure instance on the stack, fill
the fields directly on the shared ring, just like other backends do.
Build on the fact that all response structure flavors are actually
identical (the old code did make this assumption too).
This is XSA-216.
Cc: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 6b14c509f3c7..0e824091a12f 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -1433,34 +1433,35 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring, static void make_response(struct xen_blkif_ring *ring, u64 id, unsigned short op, int st) { - struct blkif_response resp; + struct blkif_response *resp; unsigned long flags; union blkif_back_rings *blk_rings; int notify; - resp.id = id; - resp.operation = op; - resp.status = st; - spin_lock_irqsave(&ring->blk_ring_lock, flags); blk_rings = &ring->blk_rings; /* Place on the response ring for the relevant domain. */ switch (ring->blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: - memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt), - &resp, sizeof(resp)); + resp = RING_GET_RESPONSE(&blk_rings->native, + blk_rings->native.rsp_prod_pvt); break; case BLKIF_PROTOCOL_X86_32: - memcpy(RING_GET_RESPONSE(&blk_rings->x86_32, blk_rings->x86_32.rsp_prod_pvt), - &resp, sizeof(resp)); + resp = RING_GET_RESPONSE(&blk_rings->x86_32, + blk_rings->x86_32.rsp_prod_pvt); break; case BLKIF_PROTOCOL_X86_64: - memcpy(RING_GET_RESPONSE(&blk_rings->x86_64, blk_rings->x86_64.rsp_prod_pvt), - &resp, sizeof(resp)); + resp = RING_GET_RESPONSE(&blk_rings->x86_64, + blk_rings->x86_64.rsp_prod_pvt); break; default: BUG(); } + + resp->id = id; + resp->operation = op; + resp->status = st; + blk_rings->common.rsp_prod_pvt++; RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify); spin_unlock_irqrestore(&ring->blk_ring_lock, flags); |