linux-kernel - [PATCH] fsck.f2fs: check and fix i

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Date:   Fri, 15 Dec 2017 14:25:30 +0800
From:   Yunlong Song <yunlong.song@...wei.com>
To:     <jaegeuk@...nel.org>, <chao@...nel.org>, <yuchao0@...wei.com>,
        <yunlong.song@...oud.com>, <yunlong.song@...wei.com>
CC:     <miaoxie@...wei.com>, <bintian.wang@...wei.com>,
        <shengyong1@...wei.com>, <heyunlei@...wei.com>,
        <linux-fsdevel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] fsck.f2fs: check and fix i_namelen to avoid double free

Signed-off-by: Yunlong Song <yunlong.song@...wei.com>
---
 fsck/fsck.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/fsck/fsck.c b/fsck/fsck.c
index 2212aa3..8ff4e4b 100644
--- a/fsck/fsck.c
+++ b/fsck/fsck.c
@@ -643,7 +643,7 @@ void fsck_chk_inode_blk(struct f2fs_sb_info *sbi, u32 nid,
 	u64 i_blocks = le64_to_cpu(node_blk->i.i_blocks);
 	int ofs = get_extra_isize(node_blk);
 	unsigned char *en;
-	int namelen;
+	int namelen, i_namelen;
 	unsigned int idx = 0;
 	int need_fix = 0;
 	int ret;
@@ -850,8 +850,21 @@ skip_blkcnt_fix:
 	en = malloc(F2FS_NAME_LEN + 1);
 	ASSERT(en);
 
-	namelen = convert_encrypted_name(node_blk->i.i_name,
-					le32_to_cpu(node_blk->i.i_namelen),
+	i_namelen = le32_to_cpu(node_blk->i.i_namelen);
+	namelen = strlen((const char *)node_blk->i.i_name);
+	if (i_namelen > F2FS_NAME_LEN) {
+		ASSERT_MSG("ino: 0x%x has i_namelen: 0x%x, "
+				"but has %d characters for name",
+				nid, i_namelen, namelen);
+		if (c.fix_on) {
+			FIX_MSG("[0x%x] i_namelen=0x%x -> 0x%x", nid, i_namelen,
+				namelen);
+			node_blk->i.i_namelen = cpu_to_le32(namelen);
+			need_fix = 1;
+		}
+		i_namelen = namelen;
+	}
+	namelen = convert_encrypted_name(node_blk->i.i_name, i_namelen,
 					en, file_enc_name(&node_blk->i));
 	en[namelen] = '\0';
 	if (ftype == F2FS_FT_ORPHAN)
-- 
1.8.5.2