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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Liu Yuntao <liuyuntao10@huawei.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 5.16 153/164] hugetlbfs: fix a truncation issue in hugepages parameter
Date:   Mon, 28 Feb 2022 18:25:15 +0100
Message-Id: <20220228172413.643077553@linuxfoundation.org>
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From: Liu Yuntao <liuyuntao10@huawei.com>

commit e79ce9832316e09529b212a21278d68240ccbf1f upstream.

When we specify a large number for node in hugepages parameter, it may
be parsed to another number due to truncation in this statement:

	node = tmp;

For example, add following parameter in command line:

	hugepagesz=1G hugepages=4294967297:5

and kernel will allocate 5 hugepages for node 1 instead of ignoring it.

I move the validation check earlier to fix this issue, and slightly
simplifies the condition here.

Link: https://lkml.kernel.org/r/20220209134018.8242-1-liuyuntao10@huawei.com
Fixes: b5389086ad7be0 ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Signed-off-by: Liu Yuntao <liuyuntao10@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 mm/hugetlb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e57650a9404f..f294db835f4b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4159,10 +4159,10 @@ static int __init hugepages_setup(char *s)
 				pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
 				return 0;
 			}
+			if (tmp >= nr_online_nodes)
+				goto invalid;
 			node = tmp;
 			p += count + 1;
-			if (node < 0 || node >= nr_online_nodes)
-				goto invalid;
 			/* Parse hugepages */
 			if (sscanf(p, "%lu%n", &tmp, &count) != 1)
 				goto invalid;
-- 
2.35.1