[PATCH v4] fsck.f2fs: check and fix i_namelen to avoid double free

[Yunlong Song]

v1 -> v2: use child_info to pass dentry namelen
v2 -> v3: check child != NULL to include the F2FS_FT_ORPHAN file type
v3 -> v4: fix the i_namelen problem of dump.f2fs

Signed-off-by: Yunlong Song <yunlong.song@xxxxxxxxxx>
---
 fsck/fsck.c | 28 +++++++++++++++++++++++-----
 fsck/fsck.h |  3 ++-
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/fsck/fsck.c b/fsck/fsck.c
index 2212aa3..5407cf2 100644
--- a/fsck/fsck.c
+++ b/fsck/fsck.c
@@ -539,7 +539,7 @@ int fsck_chk_node_blk(struct f2fs_sb_info *sbi, struct f2fs_inode *inode,
 
 		if (sanity_check_inode(sbi, node_blk))
 			goto err;
-		fsck_chk_inode_blk(sbi, nid, ftype, node_blk, blk_cnt, &ni);
+		fsck_chk_inode_blk(sbi, nid, ftype, node_blk, blk_cnt, &ni, child);
 		quota_add_inode_usage(fsck->qctx, nid, &node_blk->i);
 	} else {
 		switch (ntype) {
@@ -633,7 +633,7 @@ unmatched:
 /* start with valid nid and blkaddr */
 void fsck_chk_inode_blk(struct f2fs_sb_info *sbi, u32 nid,
 		enum FILE_TYPE ftype, struct f2fs_node *node_blk,
-		u32 *blk_cnt, struct node_info *ni)
+		u32 *blk_cnt, struct node_info *ni, struct child_info *child_d)
 {
 	struct f2fs_fsck *fsck = F2FS_FSCK(sbi);
 	struct child_info child;
@@ -850,8 +850,23 @@ 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),
+	namelen = le32_to_cpu(node_blk->i.i_namelen);
+	if (namelen > F2FS_NAME_LEN) {
+		if (child_d && child_d->i_namelen <= F2FS_NAME_LEN) {
+			ASSERT_MSG("ino: 0x%x has i_namelen: 0x%x, "
+					"but has %d characters for name",
+					nid, namelen, child_d->i_namelen);
+			if (c.fix_on) {
+				FIX_MSG("[0x%x] i_namelen=0x%x -> 0x%x", nid, namelen,
+					child_d->i_namelen);
+				node_blk->i.i_namelen = cpu_to_le32(child_d->i_namelen);
+				need_fix = 1;
+			}
+			namelen = child_d->i_namelen;
+		} else
+			namelen = F2FS_NAME_LEN;
+	}
+	namelen = convert_encrypted_name(node_blk->i.i_name, namelen,
 					en, file_enc_name(&node_blk->i));
 	en[namelen] = '\0';
 	if (ftype == F2FS_FT_ORPHAN)
@@ -1098,6 +1113,8 @@ int convert_encrypted_name(unsigned char *name, int len,
 				unsigned char *new, int enc_name)
 {
 	if (!enc_name) {
+		if (len > F2FS_NAME_LEN)
+			len = F2FS_NAME_LEN;
 		memcpy(new, name, len);
 		new[len] = 0;
 		return len;
@@ -1414,9 +1431,10 @@ static int __chk_dentries(struct f2fs_sb_info *sbi, struct child_info *child,
 				dentry, max, i, last_blk, enc_name);
 
 		blk_cnt = 1;
+		child->i_namelen = name_len;
 		ret = fsck_chk_node_blk(sbi,
 				NULL, le32_to_cpu(dentry[i].ino),
-				ftype, TYPE_INODE, &blk_cnt, NULL);
+				ftype, TYPE_INODE, &blk_cnt, child);
 
 		if (ret && c.fix_on) {
 			int j;
diff --git a/fsck/fsck.h b/fsck/fsck.h
index 0343fbd..d635c5a 100644
--- a/fsck/fsck.h
+++ b/fsck/fsck.h
@@ -54,6 +54,7 @@ struct child_info {
 	u32 pp_ino;		/*parent parent ino*/
 	struct extent_info ei;
 	u32 last_blk;
+	u32 i_namelen;  /* dentry namelen */
 };
 
 struct f2fs_fsck {
@@ -128,7 +129,7 @@ extern int fsck_chk_node_blk(struct f2fs_sb_info *, struct f2fs_inode *, u32,
 		enum FILE_TYPE, enum NODE_TYPE, u32 *,
 		struct child_info *);
 extern void fsck_chk_inode_blk(struct f2fs_sb_info *, u32, enum FILE_TYPE,
-		struct f2fs_node *, u32 *, struct node_info *);
+		struct f2fs_node *, u32 *, struct node_info *, struct child_info *);
 extern int fsck_chk_dnode_blk(struct f2fs_sb_info *, struct f2fs_inode *,
 		u32, enum FILE_TYPE, struct f2fs_node *, u32 *,
 		struct child_info *, struct node_info *);
-- 
1.8.5.2