From 243036df0d55673de59c214e240b9b914d278b65 Mon Sep 17 00:00:00 2001 From: Norbert Manthey Date: Fri, 26 Feb 2021 15:41:44 +0100 Subject: [PATCH] tools/xenstore: Harden xs_domain_is_introduced() The function single_with_domid() may return NULL if something went wrong (e.g. XenStored returns an error or the connection is in bad state). They are unlikely but not impossible, so it would be better to return an error and allow the caller to handle it gracefully rather than crashing. In this case we should treat it as the domain has disappeared (i.e. return false) as the caller will not likely going to be able to communicate with XenStored again. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. Signed-off-by: Norbert Manthey Reviewed-by: Julien Grall Reviewed-by: Raphael Ning Reviewed-by: Juergen Gross Release-Acked-by: Ian Jackson --- tools/libs/store/xs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c index b6ecbd787e..c91377c27f 100644 --- a/tools/libs/store/xs.c +++ b/tools/libs/store/xs.c @@ -1180,7 +1180,12 @@ bool xs_path_is_subpath(const char *parent, const char *child) bool xs_is_domain_introduced(struct xs_handle *h, unsigned int domid) { char *domain = single_with_domid(h, XS_IS_DOMAIN_INTRODUCED, domid); - int rc = strcmp("F", domain); + bool rc = false; + + if (!domain) + return rc; + + rc = strcmp("F", domain) != 0; free(domain); return rc; -- 2.39.5