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-rw-r--r--nbd/nbd-internal.h8
-rw-r--r--nbd/server.c18
2 files changed, 16 insertions, 10 deletions
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index 4065bc68ac..396ddb4d3e 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -38,9 +38,13 @@
*/
/* Size of all NBD_OPT_*, without payload */
-#define NBD_REQUEST_SIZE (4 + 2 + 2 + 8 + 8 + 4)
+#define NBD_REQUEST_SIZE (4 + 2 + 2 + 8 + 8 + 4)
/* Size of all NBD_REP_* sent in answer to most NBD_OPT_*, without payload */
-#define NBD_REPLY_SIZE (4 + 4 + 8)
+#define NBD_REPLY_SIZE (4 + 4 + 8)
+/* Size of reply to NBD_OPT_EXPORT_NAME */
+#define NBD_REPLY_EXPORT_NAME_SIZE (8 + 2 + 124)
+/* Size of oldstyle negotiation */
+#define NBD_OLDSTYLE_NEGOTIATE_SIZE (8 + 8 + 8 + 4 + 124)
#define NBD_REQUEST_MAGIC 0x25609513
#define NBD_REPLY_MAGIC 0x67446698
diff --git a/nbd/server.c b/nbd/server.c
index 49ed57455c..82a78bf439 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -283,12 +283,16 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,
Error **errp)
{
char name[NBD_MAX_NAME_SIZE + 1];
- char buf[8 + 4 + 124] = "";
+ char buf[NBD_REPLY_EXPORT_NAME_SIZE] = "";
size_t len;
int ret;
/* Client sends:
[20 .. xx] export name (length bytes)
+ Server replies:
+ [ 0 .. 7] size
+ [ 8 .. 9] export flags
+ [10 .. 133] reserved (0) [unless no_zeroes]
*/
trace_nbd_negotiate_handle_export_name();
if (length >= sizeof(name)) {
@@ -800,22 +804,21 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
*/
static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
{
- char buf[8 + 8 + 8 + 128];
+ char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = "";
int ret;
const uint16_t myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |
NBD_FLAG_SEND_WRITE_ZEROES);
bool oldStyle;
- /* Old style negotiation header without options
+ /* Old style negotiation header, no room for options
[ 0 .. 7] passwd ("NBDMAGIC")
[ 8 .. 15] magic (NBD_CLIENT_MAGIC)
[16 .. 23] size
- [24 .. 25] server flags (0)
- [26 .. 27] export flags
+ [24 .. 27] export flags (zero-extended)
[28 .. 151] reserved (0)
- New style negotiation header with options
+ New style negotiation header, client can send options
[ 0 .. 7] passwd ("NBDMAGIC")
[ 8 .. 15] magic (NBD_OPTS_MAGIC)
[16 .. 17] server flags (0)
@@ -825,7 +828,6 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
qio_channel_set_blocking(client->ioc, false, NULL);
trace_nbd_negotiate_begin();
- memset(buf, 0, sizeof(buf));
memcpy(buf, "NBDMAGIC", 8);
oldStyle = client->exp != NULL && !client->tlscreds;
@@ -834,7 +836,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
client->exp->nbdflags | myflags);
stq_be_p(buf + 8, NBD_CLIENT_MAGIC);
stq_be_p(buf + 16, client->exp->size);
- stw_be_p(buf + 26, client->exp->nbdflags | myflags);
+ stl_be_p(buf + 24, client->exp->nbdflags | myflags);
if (nbd_write(client->ioc, buf, sizeof(buf), errp) < 0) {
error_prepend(errp, "write failed: ");