linux-kernel - [PATCH v2 4/4] mm/msync: return ENOMEM if len overflows for msync

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Message-ID: <20230116115813.2956935-5-mawupeng1@huawei.com>
Date:   Mon, 16 Jan 2023 19:58:13 +0800
From:   Wupeng Ma <mawupeng1@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <mawupeng1@...wei.com>, <kuleshovmail@...il.com>,
        <aneesh.kumar@...ux.ibm.com>
Subject: [PATCH v2 4/4] mm/msync: return ENOMEM if len overflows for msync

From: Ma Wupeng <mawupeng1@...wei.com>

Return -ENOMEM if len overflows for msync.

Signed-off-by: Ma Wupeng <mawupeng1@...wei.com>
---
 mm/msync.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/msync.c b/mm/msync.c
index ac4c9bfea2e7..8ac227ec38af 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -36,6 +36,7 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 	struct vm_area_struct *vma;
 	int unmapped_error = 0;
 	int error = -EINVAL;
+	size_t old_len = len;
 
 	start = untagged_addr(start);
 
@@ -48,7 +49,7 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 	error = -ENOMEM;
 	len = (len + ~PAGE_MASK) & PAGE_MASK;
 	end = start + len;
-	if (end < start)
+	if (end < start || (old_len != 0 && len == 0))
 		goto out;
 	error = 0;
 	if (end == start)
-- 
2.25.1