From:   Wupeng Ma <mawupeng1@huawei.com>
To:     <akpm@linux-foundation.org>, <david@redhat.com>
CC:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <mawupeng1@huawei.com>, <kuleshovmail@gmail.com>,
        <aneesh.kumar@linux.ibm.com>
Subject: [PATCH v5 2/4] mm/mempolicy: return EINVAL for if len overflows for set_mempolicy_home_node
Date:   Tue, 21 Mar 2023 15:40:33 +0800
Message-ID: <20230321074035.1526157-3-mawupeng1@huawei.com>
In-Reply-To: <20230321074035.1526157-1-mawupeng1@huawei.com>
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From: Ma Wupeng <mawupeng1@huawei.com>

Check and return 0 if len == 0 at the beginning of the function.
Return -EINVAL if len overflows for set_mempolicy_home_node.

Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
---
 mm/mempolicy.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index a256a241fd1d..0a596c6cbed9 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1513,13 +1513,16 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
 	if (home_node >= MAX_NUMNODES || !node_online(home_node))
 		return -EINVAL;
 
+	if (!len)
+		return 0;
+
 	len = PAGE_ALIGN(len);
-	end = start + len;
+	if (!len)
+		return -EINVAL;
 
+	end = start + len;
 	if (end < start)
 		return -EINVAL;
-	if (end == start)
-		return 0;
 	mmap_write_lock(mm);
 	for_each_vma_range(vmi, vma, end) {
 		/*
-- 
2.25.1