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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, Gong Chen <gongchen4@huawei.com>,
        Sheng Yong <shengyong1@huawei.com>,
        Chao Yu <yuchao0@huawei.com>, Jaegeuk Kim <jaegeuk@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 014/212] f2fs: check if file namelen exceeds max value
Date:   Thu, 20 Aug 2020 11:19:47 +0200
Message-Id: <20200820091603.051946798@linuxfoundation.org>
In-Reply-To: <20200820091602.251285210@linuxfoundation.org>
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From: Sheng Yong <shengyong1@huawei.com>

[ Upstream commit 720db068634c91553a8e1d9a0fcd8c7050e06d2b ]

Dentry bitmap is not enough to detect incorrect dentries. So this patch
also checks the namelen value of a dentry.

Signed-off-by: Gong Chen <gongchen4@huawei.com>
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/dir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 79d138756acb5..9a11b48e55ca2 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -845,7 +845,8 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
 
 		/* check memory boundary before moving forward */
 		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
-		if (unlikely(bit_pos > d->max)) {
+		if (unlikely(bit_pos > d->max ||
+				le16_to_cpu(de->name_len) > F2FS_NAME_LEN)) {
 			f2fs_msg(F2FS_I_SB(d->inode)->sb, KERN_WARNING,
 				"%s: corrupted namelen=%d, run fsck to fix.",
 				__func__, le16_to_cpu(de->name_len));
-- 
2.25.1