[f2fs-dev] [PATCH 1/2] f2fs: fix to do sanity check on node folio during its writeback

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

Add more sanity check on node folio during its writeback, if node footer
indicates it is an inode:
- i_mode should be consistent w/ inode
- ofs_of_node should be consistent w/ non-xattr node

In addition, if sanity check fails, let's shutdown filesystem to avoid
looping to redirty and writeback it.

Cc: stable@kernel.org
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/node.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 482a362f2625..2bb9e6d35080 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1504,20 +1504,37 @@ static int sanity_check_node_footer(struct f2fs_sb_info *sbi,
 					struct folio *folio, pgoff_t nid,
 					enum node_type ntype)
 {
+	bool is_inode;
+
 	if (unlikely(nid != nid_of_node(folio)))
 		goto out_err;
 
+	is_inode = IS_INODE(folio);
+
 	switch (ntype) {
+	case NODE_TYPE_REGULAR:
+		if (is_inode) {
+			umode_t m = le16_to_cpu(F2FS_INODE(folio)->i_mode);
+
+			if (!S_ISLNK(m) && !S_ISREG(m) && !S_ISDIR(m) &&
+				!S_ISCHR(m) && !S_ISBLK(m) && !S_ISFIFO(m) &&
+				!S_ISSOCK(m))
+				goto out_err;
+
+			if (f2fs_has_xattr_block(ofs_of_node(folio)))
+				goto out_err;
+		}
+		break;
 	case NODE_TYPE_INODE:
-		if (!IS_INODE(folio))
+		if (!is_inode)
 			goto out_err;
 		break;
 	case NODE_TYPE_XATTR:
-		if (!f2fs_has_xattr_block(ofs_of_node(folio)))
+		if (is_inode || !f2fs_has_xattr_block(ofs_of_node(folio)))
 			goto out_err;
 		break;
 	case NODE_TYPE_NON_INODE:
-		if (IS_INODE(folio))
+		if (is_inode)
 			goto out_err;
 		break;
 	default:
@@ -1751,7 +1768,11 @@ static bool __write_node_folio(struct folio *folio, bool atomic, bool *submitted
 
 	/* get old block addr of this node page */
 	nid = nid_of_node(folio);
-	f2fs_bug_on(sbi, folio->index != nid);
+
+	if (sanity_check_node_footer(sbi, folio, nid, NODE_TYPE_REGULAR)) {
+		f2fs_handle_critical_error(sbi, STOP_CP_REASON_CORRUPTED_NID);
+		goto redirty_out;
+	}
 
 	if (f2fs_get_node_info(sbi, nid, &ni, !do_balance))
 		goto redirty_out;
-- 
2.49.0



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