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[Qemu-devel] [PULL 05/21] nbd/server: Hoist length check to qmp_nbd_serv
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 05/21] nbd/server: Hoist length check to qmp_nbd_server_add |
Date: |
Mon, 21 Jan 2019 16:48:51 -0600 |
We only had two callers to nbd_export_new; qemu-nbd.c always
passed a valid offset/length pair (because it already checked
the file length, to ensure that offset was in bounds), while
blockdev-nbd.c always passed 0/-1. Then nbd_export_new reduces
the size to a multiple of BDRV_SECTOR_SIZE (can only happen
when offset is not sector-aligned, since bdrv_getlength()
currently rounds up) (someday, it would be nice to have
byte-accurate lengths - but not today).
However, I'm finding it easier to work with the code if we are
consistent on having both callers pass in a valid length, and
just assert that things are sane in nbd_export_new, meaning
that no negative values were passed, and that offset+size does
not exceed 63 bits (as that really is a fundamental limit to
later operations, whether we use off_t or uint64_t).
Signed-off-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
blockdev-nbd.c | 10 +++++++++-
nbd/server.c | 10 +++-------
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index c76d5416b90..d73ac1b026a 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -146,6 +146,7 @@ void qmp_nbd_server_add(const char *device, bool has_name,
const char *name,
BlockDriverState *bs = NULL;
BlockBackend *on_eject_blk;
NBDExport *exp;
+ int64_t len;
if (!nbd_server) {
error_setg(errp, "NBD server not running");
@@ -168,6 +169,13 @@ void qmp_nbd_server_add(const char *device, bool has_name,
const char *name,
return;
}
+ len = bdrv_getlength(bs);
+ if (len < 0) {
+ error_setg_errno(errp, -len,
+ "Failed to determine the NBD export's length");
+ return;
+ }
+
if (!has_writable) {
writable = false;
}
@@ -175,7 +183,7 @@ void qmp_nbd_server_add(const char *device, bool has_name,
const char *name,
writable = false;
}
- exp = nbd_export_new(bs, 0, -1, name, NULL, bitmap,
+ exp = nbd_export_new(bs, 0, len, name, NULL, bitmap,
writable ? 0 : NBD_FLAG_READ_ONLY,
NULL, false, on_eject_blk, errp);
if (!exp) {
diff --git a/nbd/server.c b/nbd/server.c
index 6b136019f82..51ee8094e02 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1495,17 +1495,13 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t
dev_offset, off_t size,
exp->refcount = 1;
QTAILQ_INIT(&exp->clients);
exp->blk = blk;
+ assert(dev_offset >= 0 && dev_offset <= INT64_MAX);
exp->dev_offset = dev_offset;
exp->name = g_strdup(name);
exp->description = g_strdup(description);
exp->nbdflags = nbdflags;
- exp->size = size < 0 ? blk_getlength(blk) : size;
- if (exp->size < 0) {
- error_setg_errno(errp, -exp->size,
- "Failed to determine the NBD export's length");
- goto fail;
- }
- exp->size -= exp->size % BDRV_SECTOR_SIZE;
+ assert(size >= 0 && size <= INT64_MAX - dev_offset);
+ exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE);
if (bitmap) {
BdrvDirtyBitmap *bm = NULL;
--
2.20.1
- [Qemu-devel] [PULL 00/21] NBD patches through 2019-01-21, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 02/21] maint: Allow for EXAMPLES in texi2pod, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 01/21] iotests: Make 233 output more reliable, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 03/21] qemu-nbd: Enhance man page, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 04/21] qemu-nbd: Sanity check partition bounds, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 05/21] nbd/server: Hoist length check to qmp_nbd_server_add,
Eric Blake <=
- [Qemu-devel] [PULL 17/21] nbd/client: Add nbd_receive_export_list(), Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 08/21] nbd/client: Refactor nbd_receive_list(), Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 16/21] nbd/client: Refactor nbd_opt_go() to support NBD_OPT_INFO, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 06/21] nbd/server: Favor [u]int64_t over off_t, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 14/21] nbd/client: Split handshake into two functions, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 09/21] nbd/client: Move export name into NBDExportInfo, Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 11/21] nbd/client: Split out nbd_send_meta_query(), Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 18/21] nbd/client: Add meta contexts to nbd_receive_export_list(), Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 12/21] nbd/client: Split out nbd_receive_one_meta_context(), Eric Blake, 2019/01/21
- [Qemu-devel] [PULL 10/21] nbd/client: Change signature of nbd_negotiate_simple_meta_context(), Eric Blake, 2019/01/21