From 8a7ce4f9338c475df1afc12502af704e4300a3e0 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Thu, 9 Feb 2017 15:43:38 +0100 Subject: [PATCH] nbd/server: Use real permissions for NBD exports NBD can't cope with device size changes, so resize must be forbidden, but otherwise we can tolerate anything. Depending on whether the export is writable or not, we only require consistent reads and writes. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Acked-by: Fam Zheng --- nbd/server.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 89362ba760..924a1fe2db 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -891,10 +891,17 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size, { BlockBackend *blk; NBDExport *exp = g_malloc0(sizeof(NBDExport)); + uint64_t perm; int ret; - /* FIXME Use real permissions */ - blk = blk_new(0, BLK_PERM_ALL); + /* Don't allow resize while the NBD server is running, otherwise we don't + * care what happens with the node. */ + perm = BLK_PERM_CONSISTENT_READ; + if ((nbdflags & NBD_FLAG_READ_ONLY) == 0) { + perm |= BLK_PERM_WRITE; + } + blk = blk_new(perm, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | + BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD); ret = blk_insert_bs(blk, bs, errp); if (ret < 0) { goto fail;