git: 4b0d5d1d6a7c - main - libgeom: Improve type safety of xml2tree code

The branch main has been updated by des:

URL: https://cgit.FreeBSD.org/src/commit/?id=4b0d5d1d6a7c9773e38882feb4747a76b37a645c

commit 4b0d5d1d6a7c9773e38882feb4747a76b37a645c
Author:     Dag-Erling Smørgrav <des@FreeBSD.org>
AuthorDate: 2026-01-03 09:10:03 +0000
Commit:     Dag-Erling Smørgrav <des@FreeBSD.org>
CommitDate: 2026-01-03 09:10:23 +0000

    libgeom: Improve type safety of xml2tree code
    
    When resolving references, assert that the type of the object we find
    is what we expect.  This will help prevent memory corruption if two
    objects of different types somehow end up with the same identifier.
    
    MFC after:      1 week
    Reviewed by:    imp
    Differential Revision:  https://reviews.freebsd.org/D54454
---
 lib/libgeom/geom_xml2tree.c | 54 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 44 insertions(+), 10 deletions(-)

diff --git a/lib/libgeom/geom_xml2tree.c b/lib/libgeom/geom_xml2tree.c
index 81f7de1be263..03210947d431 100644
--- a/lib/libgeom/geom_xml2tree.c
+++ b/lib/libgeom/geom_xml2tree.c
@@ -36,6 +36,7 @@
 #include <sys/stat.h>
 #include <sys/sysctl.h>
 
+#include <assert.h>
 #include <ctype.h>
 #include <err.h>
 #include <errno.h>
@@ -358,14 +359,47 @@ geom_lookupid(const struct gmesh *gmp, const void *id)
 }
 
 static void *
-geom_lookupidptr(struct gmesh *gmp, const void *id)
+geom_lookup_class(const struct gmesh *gmp, const void *id)
 {
 	struct gident *gip;
 
-	gip = geom_lookupid(gmp, id);
-	if (gip)
-		return (gip->lg_ptr);
-	return (NULL);
+	if ((gip = geom_lookupid(gmp, id)) == NULL)
+		return (NULL);
+	assert(gip->lg_what == ISCLASS);
+	return (gip->lg_ptr);
+}
+
+static void *
+geom_lookup_geom(const struct gmesh *gmp, const void *id)
+{
+	struct gident *gip;
+
+	if ((gip = geom_lookupid(gmp, id)) == NULL)
+		return (NULL);
+	assert(gip->lg_what == ISGEOM);
+	return (gip->lg_ptr);
+}
+
+static void *
+geom_lookup_provider(const struct gmesh *gmp, const void *id)
+{
+	struct gident *gip;
+
+	if ((gip = geom_lookupid(gmp, id)) == NULL)
+		return (NULL);
+	assert(gip->lg_what == ISPROVIDER);
+	return (gip->lg_ptr);
+}
+
+static void * __unused
+geom_lookup_consumer(const struct gmesh *gmp, const void *id)
+{
+	struct gident *gip;
+
+	if ((gip = geom_lookupid(gmp, id)) == NULL)
+		return (NULL);
+	assert(gip->lg_what == ISCONSUMER);
+	return (gip->lg_ptr);
 }
 
 int
@@ -441,15 +475,15 @@ geom_xml2tree(struct gmesh *gmp, char *p)
 	/* Substitute all identifiers */
 	LIST_FOREACH(cl, &gmp->lg_class, lg_class) {
 		LIST_FOREACH(ge, &cl->lg_geom, lg_geom) {
-			ge->lg_class = geom_lookupidptr(gmp, ge->lg_class);
+			ge->lg_class = geom_lookup_class(gmp, ge->lg_class);
 			LIST_FOREACH(pr, &ge->lg_provider, lg_provider) {
-				pr->lg_geom = geom_lookupidptr(gmp, pr->lg_geom);
+				pr->lg_geom = geom_lookup_geom(gmp, pr->lg_geom);
 			}
 			LIST_FOREACH(co, &ge->lg_consumer, lg_consumer) {
-				co->lg_geom = geom_lookupidptr(gmp, co->lg_geom);
+				co->lg_geom = geom_lookup_geom(gmp, co->lg_geom);
 				if (co->lg_provider != NULL) {
-					co->lg_provider = geom_lookupidptr(gmp,
-						co->lg_provider);
+					co->lg_provider = geom_lookup_provider(gmp,
+					    co->lg_provider);
 					if (co->lg_provider != NULL) {
 						LIST_INSERT_HEAD(
 						    &co->lg_provider->lg_consumers,