diff options
Diffstat (limited to '0089-tools-xenstore-limit-outstanding-requests.patch')
| -rw-r--r-- | 0089-tools-xenstore-limit-outstanding-requests.patch | 453 |
1 files changed, 0 insertions, 453 deletions
diff --git a/0089-tools-xenstore-limit-outstanding-requests.patch b/0089-tools-xenstore-limit-outstanding-requests.patch deleted file mode 100644 index 2e110b0..0000000 --- a/0089-tools-xenstore-limit-outstanding-requests.patch +++ /dev/null @@ -1,453 +0,0 @@ -From 56300e8e1781cee1b6a514e5f2bea234a7885d55 Mon Sep 17 00:00:00 2001 -From: Juergen Gross <jgross@suse.com> -Date: Tue, 13 Sep 2022 07:35:08 +0200 -Subject: [PATCH 089/126] tools/xenstore: limit outstanding requests - -Add another quota for limiting the number of outstanding requests of a -guest. As the way to specify quotas on the command line is becoming -rather nasty, switch to a new scheme using [--quota|-Q] <what>=<val> -allowing to add more quotas in future easily. - -Set the default value to 20 (basically a random value not seeming to -be too high or too low). - -A request is said to be outstanding if any message generated by this -request (the direct response plus potential watch events) is not yet -completely stored into a ring buffer. The initial watch event sent as -a result of registering a watch is an exception. - -Note that across a live update the relation to buffered watch events -for other domains is lost. - -Use talloc_zero() for allocating the domain structure in order to have -all per-domain quota zeroed initially. - -This is part of XSA-326 / CVE-2022-42312. - -Signed-off-by: Juergen Gross <jgross@suse.com> -Acked-by: Julien Grall <jgrall@amazon.com> -(cherry picked from commit 36de433a273f55d614c83b89c9a8972287a1e475) ---- - tools/xenstore/xenstored_core.c | 88 +++++++++++++++++++++++++++++-- - tools/xenstore/xenstored_core.h | 20 ++++++- - tools/xenstore/xenstored_domain.c | 38 ++++++++++--- - tools/xenstore/xenstored_domain.h | 3 ++ - tools/xenstore/xenstored_watch.c | 15 ++++-- - 5 files changed, 150 insertions(+), 14 deletions(-) - -diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c -index ee3396fefa94..d871f217af9c 100644 ---- a/tools/xenstore/xenstored_core.c -+++ b/tools/xenstore/xenstored_core.c -@@ -107,6 +107,7 @@ int quota_max_entry_size = 2048; /* 2K */ - int quota_max_transaction = 10; - int quota_nb_perms_per_node = 5; - int quota_max_path_len = XENSTORE_REL_PATH_MAX; -+int quota_req_outstanding = 20; - - unsigned int timeout_watch_event_msec = 20000; - -@@ -223,12 +224,24 @@ static uint64_t get_now_msec(void) - return now_ts.tv_sec * 1000 + now_ts.tv_nsec / 1000000; - } - -+/* -+ * Remove a struct buffered_data from the list of outgoing data. -+ * A struct buffered_data related to a request having caused watch events to be -+ * sent is kept until all those events have been written out. -+ * Each watch event is referencing the related request via pend.req, while the -+ * number of watch events caused by a request is kept in pend.ref.event_cnt -+ * (those two cases are mutually exclusive, so the two fields can share memory -+ * via a union). -+ * The struct buffered_data is freed only if no related watch event is -+ * referencing it. The related return data can be freed right away. -+ */ - static void free_buffered_data(struct buffered_data *out, - struct connection *conn) - { - struct buffered_data *req; - - list_del(&out->list); -+ out->on_out_list = false; - - /* - * Update conn->timeout_msec with the next found timeout value in the -@@ -244,6 +257,30 @@ static void free_buffered_data(struct buffered_data *out, - } - } - -+ if (out->hdr.msg.type == XS_WATCH_EVENT) { -+ req = out->pend.req; -+ if (req) { -+ req->pend.ref.event_cnt--; -+ if (!req->pend.ref.event_cnt && !req->on_out_list) { -+ if (req->on_ref_list) { -+ domain_outstanding_domid_dec( -+ req->pend.ref.domid); -+ list_del(&req->list); -+ } -+ talloc_free(req); -+ } -+ } -+ } else if (out->pend.ref.event_cnt) { -+ /* Hang out off from conn. */ -+ talloc_steal(NULL, out); -+ if (out->buffer != out->default_buffer) -+ talloc_free(out->buffer); -+ list_add(&out->list, &conn->ref_list); -+ out->on_ref_list = true; -+ return; -+ } else -+ domain_outstanding_dec(conn); -+ - talloc_free(out); - } - -@@ -399,6 +436,7 @@ int delay_request(struct connection *conn, struct buffered_data *in, - static int destroy_conn(void *_conn) - { - struct connection *conn = _conn; -+ struct buffered_data *req; - - /* Flush outgoing if possible, but don't block. */ - if (!conn->domain) { -@@ -412,6 +450,11 @@ static int destroy_conn(void *_conn) - break; - close(conn->fd); - } -+ -+ conn_free_buffered_data(conn); -+ list_for_each_entry(req, &conn->ref_list, list) -+ req->on_ref_list = false; -+ - if (conn->target) - talloc_unlink(conn, conn->target); - list_del(&conn->list); -@@ -859,6 +902,8 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, - - /* Queue for later transmission. */ - list_add_tail(&bdata->list, &conn->out_list); -+ bdata->on_out_list = true; -+ domain_outstanding_inc(conn); - } - - /* -@@ -866,7 +911,8 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, - * As this is not directly related to the current command, errors can't be - * reported. - */ --void send_event(struct connection *conn, const char *path, const char *token) -+void send_event(struct buffered_data *req, struct connection *conn, -+ const char *path, const char *token) - { - struct buffered_data *bdata; - unsigned int len; -@@ -896,8 +942,13 @@ void send_event(struct connection *conn, const char *path, const char *token) - conn->timeout_msec = bdata->timeout_msec; - } - -+ bdata->pend.req = req; -+ if (req) -+ req->pend.ref.event_cnt++; -+ - /* Queue for later transmission. */ - list_add_tail(&bdata->list, &conn->out_list); -+ bdata->on_out_list = true; - } - - /* Some routines (write, mkdir, etc) just need a non-error return */ -@@ -1658,6 +1709,7 @@ static void handle_input(struct connection *conn) - return; - } - in = conn->in; -+ in->pend.ref.domid = conn->id; - - /* Not finished header yet? */ - if (in->inhdr) { -@@ -1727,6 +1779,7 @@ struct connection *new_connection(connwritefn_t *write, connreadfn_t *read) - new->is_ignored = false; - new->transaction_started = 0; - INIT_LIST_HEAD(&new->out_list); -+ INIT_LIST_HEAD(&new->ref_list); - INIT_LIST_HEAD(&new->watches); - INIT_LIST_HEAD(&new->transaction_list); - INIT_LIST_HEAD(&new->delayed); -@@ -2184,6 +2237,9 @@ static void usage(void) - " -t, --transaction <nb> limit the number of transaction allowed per domain,\n" - " -A, --perm-nb <nb> limit the number of permissions per node,\n" - " -M, --path-max <chars> limit the allowed Xenstore node path length,\n" -+" -Q, --quota <what>=<nb> set the quota <what> to the value <nb>, allowed\n" -+" quotas are:\n" -+" outstanding: number of outstanding requests\n" - " -w, --timeout <what>=<seconds> set the timeout in seconds for <what>,\n" - " allowed timeout candidates are:\n" - " watch-event: time a watch-event is kept pending\n" -@@ -2209,6 +2265,7 @@ static struct option options[] = { - { "transaction", 1, NULL, 't' }, - { "perm-nb", 1, NULL, 'A' }, - { "path-max", 1, NULL, 'M' }, -+ { "quota", 1, NULL, 'Q' }, - { "timeout", 1, NULL, 'w' }, - { "no-recovery", 0, NULL, 'R' }, - { "internal-db", 0, NULL, 'I' }, -@@ -2257,6 +2314,20 @@ static void set_timeout(const char *arg) - barf("unknown timeout \"%s\"\n", arg); - } - -+static void set_quota(const char *arg) -+{ -+ const char *eq = strchr(arg, '='); -+ int val; -+ -+ if (!eq) -+ barf("quotas must be specified via <what>=<nb>\n"); -+ val = get_optval_int(eq + 1); -+ if (what_matches(arg, "outstanding")) -+ quota_req_outstanding = val; -+ else -+ barf("unknown quota \"%s\"\n", arg); -+} -+ - int main(int argc, char *argv[]) - { - int opt; -@@ -2271,8 +2342,8 @@ int main(int argc, char *argv[]) - orig_argc = argc; - orig_argv = argv; - -- while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:T:RVW:w:U", options, -- NULL)) != -1) { -+ while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:Q:T:RVW:w:U", -+ options, NULL)) != -1) { - switch (opt) { - case 'D': - no_domain_init = true; -@@ -2320,6 +2391,9 @@ int main(int argc, char *argv[]) - quota_max_path_len = min(XENSTORE_REL_PATH_MAX, - quota_max_path_len); - break; -+ case 'Q': -+ set_quota(optarg); -+ break; - case 'w': - set_timeout(optarg); - break; -@@ -2776,6 +2850,14 @@ static void add_buffered_data(struct buffered_data *bdata, - - /* Queue for later transmission. */ - list_add_tail(&bdata->list, &conn->out_list); -+ bdata->on_out_list = true; -+ /* -+ * Watch events are never "outstanding", but the request causing them -+ * are instead kept "outstanding" until all watch events caused by that -+ * request have been delivered. -+ */ -+ if (bdata->hdr.msg.type != XS_WATCH_EVENT) -+ domain_outstanding_inc(conn); - } - - void read_state_buffered_data(const void *ctx, struct connection *conn, -diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h -index 2db577928fc6..fcb27399f116 100644 ---- a/tools/xenstore/xenstored_core.h -+++ b/tools/xenstore/xenstored_core.h -@@ -56,6 +56,8 @@ struct xs_state_connection; - struct buffered_data - { - struct list_head list; -+ bool on_out_list; -+ bool on_ref_list; - - /* Are we still doing the header? */ - bool inhdr; -@@ -63,6 +65,17 @@ struct buffered_data - /* How far are we? */ - unsigned int used; - -+ /* Outstanding request accounting. */ -+ union { -+ /* ref is being used for requests. */ -+ struct { -+ unsigned int event_cnt; /* # of outstanding events. */ -+ unsigned int domid; /* domid of request. */ -+ } ref; -+ /* req is being used for watch events. */ -+ struct buffered_data *req; /* request causing event. */ -+ } pend; -+ - union { - struct xsd_sockmsg msg; - char raw[sizeof(struct xsd_sockmsg)]; -@@ -115,6 +128,9 @@ struct connection - struct list_head out_list; - uint64_t timeout_msec; - -+ /* Referenced requests no longer pending. */ -+ struct list_head ref_list; -+ - /* Transaction context for current request (NULL if none). */ - struct transaction *transaction; - -@@ -184,7 +200,8 @@ unsigned int get_string(const struct buffered_data *data, unsigned int offset); - - void send_reply(struct connection *conn, enum xsd_sockmsg_type type, - const void *data, unsigned int len); --void send_event(struct connection *conn, const char *path, const char *token); -+void send_event(struct buffered_data *req, struct connection *conn, -+ const char *path, const char *token); - - /* Some routines (write, mkdir, etc) just need a non-error return */ - void send_ack(struct connection *conn, enum xsd_sockmsg_type type); -@@ -240,6 +257,7 @@ extern int dom0_domid; - extern int dom0_event; - extern int priv_domid; - extern int quota_nb_entry_per_domain; -+extern int quota_req_outstanding; - - extern unsigned int timeout_watch_event_msec; - -diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c -index 72a5cd3b9aaf..979f8c629835 100644 ---- a/tools/xenstore/xenstored_domain.c -+++ b/tools/xenstore/xenstored_domain.c -@@ -78,6 +78,9 @@ struct domain - /* number of watch for this domain */ - int nbwatch; - -+ /* Number of outstanding requests. */ -+ int nboutstanding; -+ - /* write rate limit */ - wrl_creditt wrl_credit; /* [ -wrl_config_writecost, +_dburst ] */ - struct wrl_timestampt wrl_timestamp; -@@ -287,8 +290,12 @@ bool domain_can_read(struct connection *conn) - { - struct xenstore_domain_interface *intf = conn->domain->interface; - -- if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0) -- return false; -+ if (domain_is_unprivileged(conn)) { -+ if (conn->domain->wrl_credit < 0) -+ return false; -+ if (conn->domain->nboutstanding >= quota_req_outstanding) -+ return false; -+ } - - if (conn->is_ignored) - return false; -@@ -337,7 +344,7 @@ static struct domain *alloc_domain(const void *context, unsigned int domid) - { - struct domain *domain; - -- domain = talloc(context, struct domain); -+ domain = talloc_zero(context, struct domain); - if (!domain) { - errno = ENOMEM; - return NULL; -@@ -398,9 +405,6 @@ static int new_domain(struct domain *domain, int port, bool restore) - domain->conn->domain = domain; - domain->conn->id = domain->domid; - -- domain->nbentry = 0; -- domain->nbwatch = 0; -- - return 0; - } - -@@ -944,6 +948,28 @@ int domain_watch(struct connection *conn) - : 0; - } - -+void domain_outstanding_inc(struct connection *conn) -+{ -+ if (!conn || !conn->domain) -+ return; -+ conn->domain->nboutstanding++; -+} -+ -+void domain_outstanding_dec(struct connection *conn) -+{ -+ if (!conn || !conn->domain) -+ return; -+ conn->domain->nboutstanding--; -+} -+ -+void domain_outstanding_domid_dec(unsigned int domid) -+{ -+ struct domain *d = find_domain_by_domid(domid); -+ -+ if (d) -+ d->nboutstanding--; -+} -+ - static wrl_creditt wrl_config_writecost = WRL_FACTOR; - static wrl_creditt wrl_config_rate = WRL_RATE * WRL_FACTOR; - static wrl_creditt wrl_config_dburst = WRL_DBURST * WRL_FACTOR; -diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h -index dc9759171317..5757a6557146 100644 ---- a/tools/xenstore/xenstored_domain.h -+++ b/tools/xenstore/xenstored_domain.h -@@ -68,6 +68,9 @@ int domain_entry(struct connection *conn); - void domain_watch_inc(struct connection *conn); - void domain_watch_dec(struct connection *conn); - int domain_watch(struct connection *conn); -+void domain_outstanding_inc(struct connection *conn); -+void domain_outstanding_dec(struct connection *conn); -+void domain_outstanding_domid_dec(unsigned int domid); - - /* Special node permission handling. */ - int set_perms_special(struct connection *conn, const char *name, -diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c -index bc6d833028a3..1d664e3d6b72 100644 ---- a/tools/xenstore/xenstored_watch.c -+++ b/tools/xenstore/xenstored_watch.c -@@ -142,6 +142,7 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, - struct node *node, bool exact, struct node_perms *perms) - { - struct connection *i; -+ struct buffered_data *req; - struct watch *watch; - - /* During transactions, don't fire watches, but queue them. */ -@@ -150,6 +151,8 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, - return; - } - -+ req = domain_is_unprivileged(conn) ? conn->in : NULL; -+ - /* Create an event for each watch. */ - list_for_each_entry(i, &connections, list) { - /* introduce/release domain watches */ -@@ -164,12 +167,12 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, - list_for_each_entry(watch, &i->watches, list) { - if (exact) { - if (streq(name, watch->node)) -- send_event(i, -+ send_event(req, i, - get_watch_path(watch, name), - watch->token); - } else { - if (is_child(name, watch->node)) -- send_event(i, -+ send_event(req, i, - get_watch_path(watch, name), - watch->token); - } -@@ -269,8 +272,12 @@ int do_watch(struct connection *conn, struct buffered_data *in) - trace_create(watch, "watch"); - send_ack(conn, XS_WATCH); - -- /* We fire once up front: simplifies clients and restart. */ -- send_event(conn, get_watch_path(watch, watch->node), watch->token); -+ /* -+ * We fire once up front: simplifies clients and restart. -+ * This event will not be linked to the XS_WATCH request. -+ */ -+ send_event(NULL, conn, get_watch_path(watch, watch->node), -+ watch->token); - - return 0; - } --- -2.37.4 - |