From c63e8fe201075982fbdf523eeee179cabb0cf376 Mon Sep 17 00:00:00 2001
From: "Andrey V. Elsukov" <ae@FreeBSD.org>
Date: Wed, 11 May 2011 19:59:43 +0000
Subject: [PATCH] Add basic metadata integrity check. In case when partition
 table was probed and read successfull, but it contains invalid values (e.g.
 overlapped partitions, offset or size is out of bounds), then table will be
 rejected.

MFC after:	1 month
---
 sys/geom/part/g_part.c | 49 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/sys/geom/part/g_part.c b/sys/geom/part/g_part.c
index 437914a15f4..aa5444e3c8f 100644
--- a/sys/geom/part/g_part.c
+++ b/sys/geom/part/g_part.c
@@ -231,6 +231,48 @@ g_part_geometry(struct g_part_table *table, struct g_consumer *cp,
 	}
 }
 
+static int
+g_part_check_integrity(struct g_part_table *table, struct g_consumer *cp)
+{
+	struct g_part_entry *e1, *e2;
+	struct g_provider *pp;
+
+	pp = cp->provider;
+	if (table->gpt_first > table->gpt_last ||
+	    table->gpt_last > pp->mediasize / pp->sectorsize - 1)
+		goto fail;
+
+	LIST_FOREACH(e1, &table->gpt_entry, gpe_entry) {
+		if (e1->gpe_deleted || e1->gpe_internal)
+			continue;
+		if (e1->gpe_start < table->gpt_first ||
+		    e1->gpe_start > table->gpt_last ||
+		    e1->gpe_end < e1->gpe_start ||
+		    e1->gpe_end > table->gpt_last)
+			goto fail;
+		e2 = e1;
+		while ((e2 = LIST_NEXT(e2, gpe_entry)) != NULL) {
+			if (e2->gpe_deleted || e2->gpe_internal)
+				continue;
+			if (e1->gpe_start >= e2->gpe_start &&
+			    e1->gpe_start <= e2->gpe_end)
+				goto fail;
+			if (e1->gpe_end >= e2->gpe_start &&
+			    e1->gpe_end <= e2->gpe_end)
+				goto fail;
+			if (e1->gpe_start < e2->gpe_start &&
+			    e1->gpe_end > e2->gpe_end)
+				goto fail;
+		}
+	}
+	return (0);
+fail:
+	if (bootverbose)
+		printf("GEOM_PART: integrity check failed (%s, %s)\n",
+		    pp->name, table->gpt_scheme->name);
+	return (EINVAL);
+}
+
 struct g_part_entry *
 g_part_new_entry(struct g_part_table *table, int index, quad_t start,
     quad_t end)
@@ -1308,11 +1350,13 @@ g_part_ctl_undo(struct gctl_req *req, struct g_part_parms *gpp)
 	}
 
 	error = G_PART_READ(table, cp);
+	if (error)
+		goto fail;
+	error = g_part_check_integrity(table, cp);
 	if (error)
 		goto fail;
 
 	g_topology_lock();
-
 	LIST_FOREACH(entry, &table->gpt_entry, gpe_entry) {
 		if (!entry->gpe_internal)
 			g_part_new_provider(gp, table, entry);
@@ -1771,6 +1815,9 @@ g_part_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
 	g_part_geometry(table, cp, pp->mediasize / pp->sectorsize);
 
 	error = G_PART_READ(table, cp);
+	if (error)
+		goto fail;
+	error = g_part_check_integrity(table, cp);
 	if (error)
 		goto fail;