From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Thu, 17 Nov 2022 19:32:36 +0000 (-0500)
Subject: maple_tree: Reduce user error potential
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=28fd1f84dc0fdbccd071d7371b5d30c964dfa93a;p=users%2Fjedix%2Flinux-maple.git

maple_tree: Reduce user error potential

When iterating, a user may modify the tree and cause the iterator to be
out of range.  Detect this scenario and correct it by setting to the
limit and invalidating the state.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ff28bd6d4745..440539ff0d11 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4735,6 +4735,11 @@ static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit)
 	unsigned long last;
 	enum maple_type mt;
 
+	if (mas->index > limit) {
+		mas->index = mas->last = limit;
+		mas_pause(mas);
+		return NULL;
+	}
 	last = mas->last;
 retry:
 	offset = mas->offset;
@@ -4841,6 +4846,11 @@ static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min)
 {
 	void *entry;
 
+	if (mas->index < min) {
+		mas->index = mas->last = min;
+		mas_pause(mas);
+		return NULL;
+	}
 retry:
 	while (likely(!mas_is_none(mas))) {
 		entry = mas_prev_nentry(mas, min, mas->index);