diff options
Diffstat (limited to '0088-tools-xenstore-let-unread-watch-events-time-out.patch')
| -rw-r--r-- | 0088-tools-xenstore-let-unread-watch-events-time-out.patch | 309 |
1 files changed, 0 insertions, 309 deletions
diff --git a/0088-tools-xenstore-let-unread-watch-events-time-out.patch b/0088-tools-xenstore-let-unread-watch-events-time-out.patch deleted file mode 100644 index 03419c6..0000000 --- a/0088-tools-xenstore-let-unread-watch-events-time-out.patch +++ /dev/null @@ -1,309 +0,0 @@ -From 53a77b82717530d836300f1de0ad037de85477dd Mon Sep 17 00:00:00 2001 -From: Juergen Gross <jgross@suse.com> -Date: Tue, 13 Sep 2022 07:35:07 +0200 -Subject: [PATCH 088/126] tools/xenstore: let unread watch events time out - -A future modification will limit the number of outstanding requests -for a domain, where "outstanding" means that the response of the -request or any resulting watch event hasn't been consumed yet. - -In order to avoid a malicious guest being capable to block other guests -by not reading watch events, add a timeout for watch events. In case a -watch event hasn't been consumed after this timeout, it is being -deleted. Set the default timeout to 20 seconds (a random value being -not too high). - -In order to support to specify other timeout values in future, use a -generic command line option for that purpose: - ---timeout|-w watch-event=<seconds> - -This is part of XSA-326 / CVE-2022-42311. - -Signed-off-by: Juergen Gross <jgross@suse.com> -Reviewed-by: Julien Grall <jgrall@amazon.com> -(cherry picked from commit 5285dcb1a5c01695c11e6397c95d906b5e765c98) ---- - tools/xenstore/xenstored_core.c | 133 +++++++++++++++++++++++++++++++- - tools/xenstore/xenstored_core.h | 6 ++ - 2 files changed, 138 insertions(+), 1 deletion(-) - -diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c -index 5157a7527f58..ee3396fefa94 100644 ---- a/tools/xenstore/xenstored_core.c -+++ b/tools/xenstore/xenstored_core.c -@@ -108,6 +108,8 @@ int quota_max_transaction = 10; - int quota_nb_perms_per_node = 5; - int quota_max_path_len = XENSTORE_REL_PATH_MAX; - -+unsigned int timeout_watch_event_msec = 20000; -+ - void trace(const char *fmt, ...) - { - va_list arglist; -@@ -211,19 +213,92 @@ void reopen_log(void) - } - } - -+static uint64_t get_now_msec(void) -+{ -+ struct timespec now_ts; -+ -+ if (clock_gettime(CLOCK_MONOTONIC, &now_ts)) -+ barf_perror("Could not find time (clock_gettime failed)"); -+ -+ return now_ts.tv_sec * 1000 + now_ts.tv_nsec / 1000000; -+} -+ - static void free_buffered_data(struct buffered_data *out, - struct connection *conn) - { -+ struct buffered_data *req; -+ - list_del(&out->list); -+ -+ /* -+ * Update conn->timeout_msec with the next found timeout value in the -+ * queued pending requests. -+ */ -+ if (out->timeout_msec) { -+ conn->timeout_msec = 0; -+ list_for_each_entry(req, &conn->out_list, list) { -+ if (req->timeout_msec) { -+ conn->timeout_msec = req->timeout_msec; -+ break; -+ } -+ } -+ } -+ - talloc_free(out); - } - -+static void check_event_timeout(struct connection *conn, uint64_t msecs, -+ int *ptimeout) -+{ -+ uint64_t delta; -+ struct buffered_data *out, *tmp; -+ -+ if (!conn->timeout_msec) -+ return; -+ -+ delta = conn->timeout_msec - msecs; -+ if (conn->timeout_msec <= msecs) { -+ delta = 0; -+ list_for_each_entry_safe(out, tmp, &conn->out_list, list) { -+ /* -+ * Only look at buffers with timeout and no data -+ * already written to the ring. -+ */ -+ if (out->timeout_msec && out->inhdr && !out->used) { -+ if (out->timeout_msec > msecs) { -+ conn->timeout_msec = out->timeout_msec; -+ delta = conn->timeout_msec - msecs; -+ break; -+ } -+ -+ /* -+ * Free out without updating conn->timeout_msec, -+ * as the update is done in this loop already. -+ */ -+ out->timeout_msec = 0; -+ trace("watch event path %s for domain %u timed out\n", -+ out->buffer, conn->id); -+ free_buffered_data(out, conn); -+ } -+ } -+ if (!delta) { -+ conn->timeout_msec = 0; -+ return; -+ } -+ } -+ -+ if (*ptimeout == -1 || *ptimeout > delta) -+ *ptimeout = delta; -+} -+ - void conn_free_buffered_data(struct connection *conn) - { - struct buffered_data *out; - - while ((out = list_top(&conn->out_list, struct buffered_data, list))) - free_buffered_data(out, conn); -+ -+ conn->timeout_msec = 0; - } - - static bool write_messages(struct connection *conn) -@@ -382,6 +457,7 @@ static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout) - { - struct connection *conn; - struct wrl_timestampt now; -+ uint64_t msecs; - - if (fds) - memset(fds, 0, sizeof(struct pollfd) * current_array_size); -@@ -402,10 +478,12 @@ static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout) - - wrl_gettime_now(&now); - wrl_log_periodic(now); -+ msecs = get_now_msec(); - - list_for_each_entry(conn, &connections, list) { - if (conn->domain) { - wrl_check_timeout(conn->domain, now, ptimeout); -+ check_event_timeout(conn, msecs, ptimeout); - if (domain_can_read(conn) || - (domain_can_write(conn) && - !list_empty(&conn->out_list))) -@@ -760,6 +838,7 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, - return; - bdata->inhdr = true; - bdata->used = 0; -+ bdata->timeout_msec = 0; - - if (len <= DEFAULT_BUFFER_SIZE) - bdata->buffer = bdata->default_buffer; -@@ -811,6 +890,12 @@ void send_event(struct connection *conn, const char *path, const char *token) - bdata->hdr.msg.type = XS_WATCH_EVENT; - bdata->hdr.msg.len = len; - -+ if (timeout_watch_event_msec && domain_is_unprivileged(conn)) { -+ bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; -+ if (!conn->timeout_msec) -+ conn->timeout_msec = bdata->timeout_msec; -+ } -+ - /* Queue for later transmission. */ - list_add_tail(&bdata->list, &conn->out_list); - } -@@ -2099,6 +2184,9 @@ 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" -+" -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" - " -R, --no-recovery to request that no recovery should be attempted when\n" - " the store is corrupted (debug only),\n" - " -I, --internal-db store database in memory, not on disk\n" -@@ -2121,6 +2209,7 @@ static struct option options[] = { - { "transaction", 1, NULL, 't' }, - { "perm-nb", 1, NULL, 'A' }, - { "path-max", 1, NULL, 'M' }, -+ { "timeout", 1, NULL, 'w' }, - { "no-recovery", 0, NULL, 'R' }, - { "internal-db", 0, NULL, 'I' }, - { "verbose", 0, NULL, 'V' }, -@@ -2135,6 +2224,39 @@ int dom0_domid = 0; - int dom0_event = 0; - int priv_domid = 0; - -+static int get_optval_int(const char *arg) -+{ -+ char *end; -+ long val; -+ -+ val = strtol(arg, &end, 10); -+ if (!*arg || *end || val < 0 || val > INT_MAX) -+ barf("invalid parameter value \"%s\"\n", arg); -+ -+ return val; -+} -+ -+static bool what_matches(const char *arg, const char *what) -+{ -+ unsigned int what_len = strlen(what); -+ -+ return !strncmp(arg, what, what_len) && arg[what_len] == '='; -+} -+ -+static void set_timeout(const char *arg) -+{ -+ const char *eq = strchr(arg, '='); -+ int val; -+ -+ if (!eq) -+ barf("quotas must be specified via <what>=<seconds>\n"); -+ val = get_optval_int(eq + 1); -+ if (what_matches(arg, "watch-event")) -+ timeout_watch_event_msec = val * 1000; -+ else -+ barf("unknown timeout \"%s\"\n", arg); -+} -+ - int main(int argc, char *argv[]) - { - int opt; -@@ -2149,7 +2271,7 @@ 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:U", options, -+ while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:T:RVW:w:U", options, - NULL)) != -1) { - switch (opt) { - case 'D': -@@ -2198,6 +2320,9 @@ int main(int argc, char *argv[]) - quota_max_path_len = min(XENSTORE_REL_PATH_MAX, - quota_max_path_len); - break; -+ case 'w': -+ set_timeout(optarg); -+ break; - case 'e': - dom0_event = strtol(optarg, NULL, 10); - break; -@@ -2642,6 +2767,12 @@ static void add_buffered_data(struct buffered_data *bdata, - barf("error restoring buffered data"); - - memcpy(bdata->buffer, data, len); -+ if (bdata->hdr.msg.type == XS_WATCH_EVENT && timeout_watch_event_msec && -+ domain_is_unprivileged(conn)) { -+ bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; -+ if (!conn->timeout_msec) -+ conn->timeout_msec = bdata->timeout_msec; -+ } - - /* Queue for later transmission. */ - list_add_tail(&bdata->list, &conn->out_list); -diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h -index 0ba5b783d4d1..2db577928fc6 100644 ---- a/tools/xenstore/xenstored_core.h -+++ b/tools/xenstore/xenstored_core.h -@@ -27,6 +27,7 @@ - #include <dirent.h> - #include <stdbool.h> - #include <stdint.h> -+#include <time.h> - #include <errno.h> - - #include "xenstore_lib.h" -@@ -67,6 +68,8 @@ struct buffered_data - char raw[sizeof(struct xsd_sockmsg)]; - } hdr; - -+ uint64_t timeout_msec; -+ - /* The actual data. */ - char *buffer; - char default_buffer[DEFAULT_BUFFER_SIZE]; -@@ -110,6 +113,7 @@ struct connection - - /* Buffered output data */ - struct list_head out_list; -+ uint64_t timeout_msec; - - /* Transaction context for current request (NULL if none). */ - struct transaction *transaction; -@@ -237,6 +241,8 @@ extern int dom0_event; - extern int priv_domid; - extern int quota_nb_entry_per_domain; - -+extern unsigned int timeout_watch_event_msec; -+ - /* Map the kernel's xenstore page. */ - void *xenbus_map(void); - void unmap_xenbus(void *interface); --- -2.37.4 - |