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Re: [Qemu-block] [PATCH v5 05/11] nbd/server: Refactor zero-length optio
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From: |
Vladimir Sementsov-Ogievskiy |
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Subject: |
Re: [Qemu-block] [PATCH v5 05/11] nbd/server: Refactor zero-length option check |
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Date: |
Fri, 20 Oct 2017 11:34:08 +0300 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
20.10.2017 01:26, Eric Blake wrote:
Consolidate the check for a zero-length payload to an option
into a new function, nbd_check_zero_length(); this check will
also be used when introducing support for structured replies.
By sticking a catch-all check at the end of the loop for
processing options, we can simplify several of the intermediate
cases.
Signed-off-by: Eric Blake <address@hidden>
looks like two patches in one, however I'm not against (considering my
big patches =)).
I've already put an r-b here but suddenly understood a hidden behavior
change you've made,
which may considered like a bug, see below.
---
nbd/server.c | 76 +++++++++++++++++++++++++++---------------------------------
1 file changed, 34 insertions(+), 42 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 05ff7470d5..b3f7e0b18e 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -253,21 +253,10 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc,
NBDExport *exp,
/* Process the NBD_OPT_LIST command, with a potential series of replies.
* Return -errno on error, 0 on success. */
-static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length,
- Error **errp)
+static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
{
NBDExport *exp;
- if (length) {
- if (nbd_drop(client->ioc, length, errp) < 0) {
- return -EIO;
- }
- return nbd_negotiate_send_rep_err(client->ioc,
- NBD_REP_ERR_INVALID, NBD_OPT_LIST,
- errp,
- "OPT_LIST should not have length");
- }
-
/* For each export, send a NBD_REP_SERVER reply. */
QTAILQ_FOREACH(exp, &exports, next) {
if (nbd_negotiate_send_rep_list(client->ioc, exp, errp)) {
@@ -531,7 +520,6 @@ static int nbd_negotiate_handle_info(NBDClient *client,
uint32_t length,
/* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the
* new channel for all further (now-encrypted) communication. */
static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
- uint32_t length,
Error **errp)
{
QIOChannel *ioc;
@@ -540,15 +528,6 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient
*client,
trace_nbd_negotiate_handle_starttls();
ioc = client->ioc;
- if (length) {
- if (nbd_drop(ioc, length, errp) < 0) {
- return NULL;
- }
- nbd_negotiate_send_rep_err(ioc, NBD_REP_ERR_INVALID, NBD_OPT_STARTTLS,
- errp,
- "OPT_STARTTLS should not have length");
- return NULL;
- }
if (nbd_negotiate_send_rep(client->ioc, NBD_REP_ACK,
NBD_OPT_STARTTLS, errp) < 0) {
@@ -584,6 +563,25 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient
*client,
return QIO_CHANNEL(tioc);
}
+/* nbd_check_zero_length: Handle any unexpected payload.
+ * Return:
+ * -errno on error, errp is set
+ * 0 on successful negotiation, errp is not set
+ */
+static int nbd_check_zero_length(NBDClient *client, uint32_t length,
+ uint32_t option, Error **errp)
+{
+ if (!length) {
+ return 0;
+ }
+ if (nbd_drop(client->ioc, length, errp) < 0) {
+ return -EIO;
+ }
+ return nbd_negotiate_send_rep_err(client->ioc, NBD_REP_ERR_INVALID, option,
+ errp, "option %s should have zero
length",
may be quotes around %s or your trace-notation %d (%s) would be more
readable
+ nbd_opt_lookup(option));
+}
+
/* nbd_negotiate_options
* Process all NBD_OPT_* client option commands, during fixed newstyle
* negotiation.
@@ -674,7 +672,11 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
}
switch (option) {
case NBD_OPT_STARTTLS:
- tioc = nbd_negotiate_handle_starttls(client, length, errp);
+ ret = nbd_check_zero_length(client, length, option, errp);
+ if (ret < 0) {
+ return ret;
+ }
no, you should not continue if length>0 (old behavior).
nbd_negotiate_send_rep_err returns 0 on success
in nbd_check_zero_length().
+ tioc = nbd_negotiate_handle_starttls(client, errp);
if (!tioc) {
return -EIO;
}
@@ -698,9 +700,6 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
"Option 0x%" PRIx32
"not permitted before TLS",
option);
- if (ret < 0) {
- return ret;
- }
/* Let the client keep trying, unless they asked to
* quit. In this mode, we've already sent an error, so
* we can't ack the abort. */
@@ -712,9 +711,9 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
} else if (fixedNewstyle) {
switch (option) {
case NBD_OPT_LIST:
- ret = nbd_negotiate_handle_list(client, length, errp);
- if (ret < 0) {
- return ret;
+ ret = nbd_check_zero_length(client, length, option, errp);
+ if (!ret) {
the same here
+ ret = nbd_negotiate_handle_list(client, errp);
}
break;
@@ -738,16 +737,12 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
assert(option == NBD_OPT_GO);
return 0;
}
- if (ret) {
- return ret;
- }
break;
case NBD_OPT_STARTTLS:
- if (nbd_drop(client->ioc, length, errp) < 0) {
- return -EIO;
- }
- if (client->tlscreds) {
+ if (length) {
+ ret = nbd_check_zero_length(client, length, option, errp);
+ } else if (client->tlscreds) {
ret = nbd_negotiate_send_rep_err(client->ioc,
NBD_REP_ERR_INVALID,
option, errp,
@@ -758,9 +753,6 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
option, errp,
"TLS not configured");
}
- if (ret < 0) {
- return ret;
- }
break;
default:
if (nbd_drop(client->ioc, length, errp) < 0) {
@@ -772,9 +764,6 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
"Unsupported option 0x%"
PRIx32 " (%s)", option,
nbd_opt_lookup(option));
- if (ret < 0) {
- return ret;
- }
break;
}
} else {
@@ -794,6 +783,9 @@ static int nbd_negotiate_options(NBDClient *client,
uint16_t myflags,
return -EINVAL;
}
}
+ if (ret < 0) {
+ return ret;
+ }
}
}
--
Best regards,
Vladimir
- [Qemu-block] [PATCH v5 00/11] nbd minimal structured read, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 02/11] nbd: Move nbd_errno_to_system_errno() to public header, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 04/11] nbd/server: Report error for write to read-only export, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 03/11] nbd: Expose constants and structs for structured read, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 01/11] nbd: Include error names in trace messages, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 05/11] nbd/server: Refactor zero-length option check, Eric Blake, 2017/10/19
- Re: [Qemu-block] [PATCH v5 05/11] nbd/server: Refactor zero-length option check,
Vladimir Sementsov-Ogievskiy <=
- [Qemu-block] [PATCH v5 08/11] nbd/client: refactor nbd_receive_starttls, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 09/11] nbd/client: prepare nbd_receive_reply for structured reply, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 10/11] nbd: Move nbd_read() to common header, Eric Blake, 2017/10/19
- [Qemu-block] [PATCH v5 06/11] nbd: Minimal structured read for server, Eric Blake, 2017/10/19