tools/xenstore/xenstored_core.c | 3 +++ tools/xenstore/xenstored_domain.c | 4 ++-- tools/xenstore/xenstored_domain.h | 7 ++++++- tools/xenstore/xenstored_transaction.c | 16 ++++++++++++++-- tools/xenstore/xenstored_transaction.h | 3 +++ 5 files changed, 28 insertions(+), 5 deletions(-)
Today when finalizing a transaction the number of node quota is checked
to not being exceeded after the transaction. This check is always done,
even if the transaction is being performed by a privileged connection,
or if there were no nodes created in the transaction.
Correct that by checking quota only if:
- the transaction is being performed by an unprivileged guest, and
- at least one node was created in the transaction
Reported-by: Julien Grall <julien@xen.org>
Fixes: f2bebf72c4d5 ("xenstore: rework of transaction handling")
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- add comment (Julien Grall)
---
tools/xenstore/xenstored_core.c | 3 +++
tools/xenstore/xenstored_domain.c | 4 ++--
tools/xenstore/xenstored_domain.h | 7 ++++++-
tools/xenstore/xenstored_transaction.c | 16 ++++++++++++++--
tools/xenstore/xenstored_transaction.h | 3 +++
5 files changed, 28 insertions(+), 5 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index a61db2db2d..3ca68681e3 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1472,6 +1472,9 @@ static struct node *create_node(struct connection *conn, const void *ctx,
if (!node)
return NULL;
+ if (conn && conn->transaction)
+ ta_node_created(conn->transaction);
+
node->data = data;
node->datalen = datalen;
diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index d7fc2fafc7..f62be2245c 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -544,7 +544,7 @@ static struct domain *find_domain_by_domid(unsigned int domid)
return (d && d->introduced) ? d : NULL;
}
-int acc_fix_domains(struct list_head *head, bool update)
+int acc_fix_domains(struct list_head *head, bool chk_quota, bool update)
{
struct changed_domain *cd;
int cnt;
@@ -552,7 +552,7 @@ int acc_fix_domains(struct list_head *head, bool update)
list_for_each_entry(cd, head, list) {
cnt = domain_nbentry_fix(cd->domid, cd->nbentry, update);
if (!update) {
- if (cnt >= quota_nb_entry_per_domain)
+ if (chk_quota && cnt >= quota_nb_entry_per_domain)
return ENOSPC;
if (cnt < 0)
return ENOMEM;
diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
index dc4660861e..279cccb3ad 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -96,7 +96,12 @@ void domain_outstanding_dec(struct connection *conn);
void domain_outstanding_domid_dec(unsigned int domid);
int domain_get_quota(const void *ctx, struct connection *conn,
unsigned int domid);
-int acc_fix_domains(struct list_head *head, bool update);
+
+/*
+ * Update or check number of nodes per domain at the end of a transaction.
+ * If "update" is true, "chk_quota" is ignored.
+ */
+int acc_fix_domains(struct list_head *head, bool chk_quota, bool update);
/* Write rate limiting */
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index 1aa9d3cb3d..2b15506953 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -160,12 +160,20 @@ struct transaction
/* List of changed domains - to record the changed domain entry number */
struct list_head changed_domains;
+ /* There was at least one node created in the transaction. */
+ bool node_created;
+
/* Flag for letting transaction fail. */
bool fail;
};
uint64_t generation;
+void ta_node_created(struct transaction *trans)
+{
+ trans->node_created = true;
+}
+
static struct accessed_node *find_accessed_node(struct transaction *trans,
const char *name)
{
@@ -509,6 +517,7 @@ int do_transaction_end(const void *ctx, struct connection *conn,
const char *arg = onearg(in);
struct transaction *trans;
bool is_corrupt = false;
+ bool chk_quota;
int ret;
if (!arg || (!streq(arg, "T") && !streq(arg, "F")))
@@ -523,13 +532,16 @@ int do_transaction_end(const void *ctx, struct connection *conn,
if (!conn->transaction_started)
conn->ta_start_time = 0;
+ chk_quota = trans->node_created && domain_is_unprivileged(conn);
+
/* Attach transaction to ctx for auto-cleanup */
talloc_steal(ctx, trans);
if (streq(arg, "T")) {
if (trans->fail)
return ENOMEM;
- ret = acc_fix_domains(&trans->changed_domains, false);
+ ret = acc_fix_domains(&trans->changed_domains, chk_quota,
+ false);
if (ret)
return ret;
ret = finalize_transaction(conn, trans, &is_corrupt);
@@ -539,7 +551,7 @@ int do_transaction_end(const void *ctx, struct connection *conn,
wrl_apply_debit_trans_commit(conn);
/* fix domain entry for each changed domain */
- acc_fix_domains(&trans->changed_domains, true);
+ acc_fix_domains(&trans->changed_domains, false, true);
if (is_corrupt)
corrupt(conn, "transaction inconsistency");
diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h
index b6f8cb7d0a..883145163f 100644
--- a/tools/xenstore/xenstored_transaction.h
+++ b/tools/xenstore/xenstored_transaction.h
@@ -36,6 +36,9 @@ int do_transaction_end(const void *ctx, struct connection *conn,
struct transaction *transaction_lookup(struct connection *conn, uint32_t id);
+/* Set flag for created node. */
+void ta_node_created(struct transaction *trans);
+
/* This node was accessed. */
int __must_check access_node(struct connection *conn, struct node *node,
enum node_access_type type, TDB_DATA *key);
--
2.35.3On 28.03.2023 16:43, Juergen Gross wrote:
> Today when finalizing a transaction the number of node quota is checked
> to not being exceeded after the transaction. This check is always done,
> even if the transaction is being performed by a privileged connection,
> or if there were no nodes created in the transaction.
>
> Correct that by checking quota only if:
> - the transaction is being performed by an unprivileged guest, and
> - at least one node was created in the transaction
>
> Reported-by: Julien Grall <julien@xen.org>
> Fixes: f2bebf72c4d5 ("xenstore: rework of transaction handling")
> Signed-off-by: Juergen Gross <jgross@suse.com>
Considering the referenced commit is about 6 years old, I thought this
would be a backporting candidate. The function mentioned in the title
doesn't appear to exist on 4.17, though. Therefore, if there is an
intention for this to be backported, may I please ask that a suitable
backport be provided?
Thanks, Jan
On 24.04.23 10:56, Jan Beulich wrote:
> On 28.03.2023 16:43, Juergen Gross wrote:
>> Today when finalizing a transaction the number of node quota is checked
>> to not being exceeded after the transaction. This check is always done,
>> even if the transaction is being performed by a privileged connection,
>> or if there were no nodes created in the transaction.
>>
>> Correct that by checking quota only if:
>> - the transaction is being performed by an unprivileged guest, and
>> - at least one node was created in the transaction
>>
>> Reported-by: Julien Grall <julien@xen.org>
>> Fixes: f2bebf72c4d5 ("xenstore: rework of transaction handling")
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>
> Considering the referenced commit is about 6 years old, I thought this
> would be a backporting candidate. The function mentioned in the title
> doesn't appear to exist on 4.17, though. Therefore, if there is an
> intention for this to be backported, may I please ask that a suitable
> backport be provided?
This should do the job.
Juergen
Hi Juergen,
On 28/03/2023 15:43, Juergen Gross wrote:
> Today when finalizing a transaction the number of node quota is checked
> to not being exceeded after the transaction. This check is always done,
> even if the transaction is being performed by a privileged connection,
> or if there were no nodes created in the transaction.
>
> Correct that by checking quota only if:
> - the transaction is being performed by an unprivileged guest, and
> - at least one node was created in the transaction
>
> Reported-by: Julien Grall <julien@xen.org>
> Fixes: f2bebf72c4d5 ("xenstore: rework of transaction handling")
> Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
And committed.
Cheers,
> ---
> V2:
> - add comment (Julien Grall)
> ---
> tools/xenstore/xenstored_core.c | 3 +++
> tools/xenstore/xenstored_domain.c | 4 ++--
> tools/xenstore/xenstored_domain.h | 7 ++++++-
> tools/xenstore/xenstored_transaction.c | 16 ++++++++++++++--
> tools/xenstore/xenstored_transaction.h | 3 +++
> 5 files changed, 28 insertions(+), 5 deletions(-)
>
> diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
> index a61db2db2d..3ca68681e3 100644
> --- a/tools/xenstore/xenstored_core.c
> +++ b/tools/xenstore/xenstored_core.c
> @@ -1472,6 +1472,9 @@ static struct node *create_node(struct connection *conn, const void *ctx,
> if (!node)
> return NULL;
>
> + if (conn && conn->transaction)
> + ta_node_created(conn->transaction);
> +
> node->data = data;
> node->datalen = datalen;
>
> diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
> index d7fc2fafc7..f62be2245c 100644
> --- a/tools/xenstore/xenstored_domain.c
> +++ b/tools/xenstore/xenstored_domain.c
> @@ -544,7 +544,7 @@ static struct domain *find_domain_by_domid(unsigned int domid)
> return (d && d->introduced) ? d : NULL;
> }
>
> -int acc_fix_domains(struct list_head *head, bool update)
> +int acc_fix_domains(struct list_head *head, bool chk_quota, bool update)
> {
> struct changed_domain *cd;
> int cnt;
> @@ -552,7 +552,7 @@ int acc_fix_domains(struct list_head *head, bool update)
> list_for_each_entry(cd, head, list) {
> cnt = domain_nbentry_fix(cd->domid, cd->nbentry, update);
> if (!update) {
> - if (cnt >= quota_nb_entry_per_domain)
> + if (chk_quota && cnt >= quota_nb_entry_per_domain)
> return ENOSPC;
> if (cnt < 0)
> return ENOMEM;
> diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
> index dc4660861e..279cccb3ad 100644
> --- a/tools/xenstore/xenstored_domain.h
> +++ b/tools/xenstore/xenstored_domain.h
> @@ -96,7 +96,12 @@ void domain_outstanding_dec(struct connection *conn);
> void domain_outstanding_domid_dec(unsigned int domid);
> int domain_get_quota(const void *ctx, struct connection *conn,
> unsigned int domid);
> -int acc_fix_domains(struct list_head *head, bool update);
> +
> +/*
> + * Update or check number of nodes per domain at the end of a transaction.
> + * If "update" is true, "chk_quota" is ignored.
> + */
> +int acc_fix_domains(struct list_head *head, bool chk_quota, bool update);
>
> /* Write rate limiting */
>
> diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
> index 1aa9d3cb3d..2b15506953 100644
> --- a/tools/xenstore/xenstored_transaction.c
> +++ b/tools/xenstore/xenstored_transaction.c
> @@ -160,12 +160,20 @@ struct transaction
> /* List of changed domains - to record the changed domain entry number */
> struct list_head changed_domains;
>
> + /* There was at least one node created in the transaction. */
> + bool node_created;
> +
> /* Flag for letting transaction fail. */
> bool fail;
> };
>
> uint64_t generation;
>
> +void ta_node_created(struct transaction *trans)
> +{
> + trans->node_created = true;
> +}
> +
> static struct accessed_node *find_accessed_node(struct transaction *trans,
> const char *name)
> {
> @@ -509,6 +517,7 @@ int do_transaction_end(const void *ctx, struct connection *conn,
> const char *arg = onearg(in);
> struct transaction *trans;
> bool is_corrupt = false;
> + bool chk_quota;
> int ret;
>
> if (!arg || (!streq(arg, "T") && !streq(arg, "F")))
> @@ -523,13 +532,16 @@ int do_transaction_end(const void *ctx, struct connection *conn,
> if (!conn->transaction_started)
> conn->ta_start_time = 0;
>
> + chk_quota = trans->node_created && domain_is_unprivileged(conn);
> +
> /* Attach transaction to ctx for auto-cleanup */
> talloc_steal(ctx, trans);
>
> if (streq(arg, "T")) {
> if (trans->fail)
> return ENOMEM;
> - ret = acc_fix_domains(&trans->changed_domains, false);
> + ret = acc_fix_domains(&trans->changed_domains, chk_quota,
> + false);
> if (ret)
> return ret;
> ret = finalize_transaction(conn, trans, &is_corrupt);
> @@ -539,7 +551,7 @@ int do_transaction_end(const void *ctx, struct connection *conn,
> wrl_apply_debit_trans_commit(conn);
>
> /* fix domain entry for each changed domain */
> - acc_fix_domains(&trans->changed_domains, true);
> + acc_fix_domains(&trans->changed_domains, false, true);
>
> if (is_corrupt)
> corrupt(conn, "transaction inconsistency");
> diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h
> index b6f8cb7d0a..883145163f 100644
> --- a/tools/xenstore/xenstored_transaction.h
> +++ b/tools/xenstore/xenstored_transaction.h
> @@ -36,6 +36,9 @@ int do_transaction_end(const void *ctx, struct connection *conn,
>
> struct transaction *transaction_lookup(struct connection *conn, uint32_t id);
>
> +/* Set flag for created node. */
> +void ta_node_created(struct transaction *trans);
> +
> /* This node was accessed. */
> int __must_check access_node(struct connection *conn, struct node *node,
> enum node_access_type type, TDB_DATA *key);
--
Julien Grall
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