f2fs: fix to do sanity check on node footer for non inode dnode

commit c18ecd99e0c707ef8f83cace861cbc3162f4fdf1 upstream.

As syzbot reported below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/file.c:1243!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5354 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full)
RIP: 0010:f2fs_truncate_hole+0x69e/0x6c0 fs/f2fs/file.c:1243
Call Trace:
 <TASK>
 f2fs_punch_hole+0x2db/0x330 fs/f2fs/file.c:1306
 f2fs_fallocate+0x546/0x990 fs/f2fs/file.c:2018
 vfs_fallocate+0x666/0x7e0 fs/open.c:342
 ksys_fallocate fs/open.c:366 [inline]
 __do_sys_fallocate fs/open.c:371 [inline]
 __se_sys_fallocate fs/open.c:369 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:369
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1e65f8ebe9

w/ a fuzzed image, f2fs may encounter panic due to it detects inconsistent
truncation range in direct node in f2fs_truncate_hole().

The root cause is: a non-inode dnode may has the same footer.ino and
footer.nid, so the dnode will be parsed as an inode, then ADDRS_PER_PAGE()
may return wrong blkaddr count which may be 923 typically, by chance,
dn.ofs_in_node is equal to 923, then count can be calculated to 0 in below
statement, later it will trigger panic w/ f2fs_bug_on(, count == 0 || ...).

	count = min(end_offset - dn.ofs_in_node, pg_end - pg_start);

This patch introduces a new node_type NODE_TYPE_NON_INODE, then allowing
passing the new_type to sanity_check_node_footer in f2fs_get_node_folio()
to detect corruption that a non-inode dnode has the same footer.ino and
footer.nid.

Scripts to reproduce:
mkfs.f2fs -f /dev/vdb
mount /dev/vdb /mnt/f2fs
touch /mnt/f2fs/foo
touch /mnt/f2fs/bar
dd if=/dev/zero of=/mnt/f2fs/foo bs=1M count=8
umount /mnt/f2fs
inject.f2fs --node --mb i_nid --nid 4 --idx 0 --val 5 /dev/vdb
mount /dev/vdb /mnt/f2fs
xfs_io /mnt/f2fs/foo -c "fpunch 6984k 4k"

Cc: stable@kernel.org
Reported-by: syzbot+b9c7ffd609c3f09416ab@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/68a68e27.050a0220.1a3988.0002.GAE@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 39 insertions, 19 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 27743b93e186..92054dcbe20d 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -871,7 +871,8 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
 		}
 
 		if (!done) {
-			nfolio[i] = f2fs_get_node_folio(sbi, nids[i]);
+			nfolio[i] = f2fs_get_node_folio(sbi, nids[i],
+						NODE_TYPE_NON_INODE);
 			if (IS_ERR(nfolio[i])) {
 				err = PTR_ERR(nfolio[i]);
 				f2fs_folio_put(nfolio[0], false);
@@ -989,7 +990,7 @@ static int truncate_dnode(struct dnode_of_data *dn)
 		return 1;
 
 	/* get direct node */
-	folio = f2fs_get_node_folio(sbi, dn->nid);
+	folio = f2fs_get_node_folio(sbi, dn->nid, NODE_TYPE_NON_INODE);
 	if (PTR_ERR(folio) == -ENOENT)
 		return 1;
 	else if (IS_ERR(folio))
@@ -1033,7 +1034,8 @@ static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs,
 
 	trace_f2fs_truncate_nodes_enter(dn->inode, dn->nid, dn->data_blkaddr);
 
-	folio = f2fs_get_node_folio(F2FS_I_SB(dn->inode), dn->nid);
+	folio = f2fs_get_node_folio(F2FS_I_SB(dn->inode), dn->nid,
+						NODE_TYPE_NON_INODE);
 	if (IS_ERR(folio)) {
 		trace_f2fs_truncate_nodes_exit(dn->inode, PTR_ERR(folio));
 		return PTR_ERR(folio);
@@ -1111,7 +1113,8 @@ static int truncate_partial_nodes(struct dnode_of_data *dn,
 	/* get indirect nodes in the path */
 	for (i = 0; i < idx + 1; i++) {
 		/* reference count'll be increased */
-		folios[i] = f2fs_get_node_folio(F2FS_I_SB(dn->inode), nid[i]);
+		folios[i] = f2fs_get_node_folio(F2FS_I_SB(dn->inode), nid[i],
+							NODE_TYPE_NON_INODE);
 		if (IS_ERR(folios[i])) {
 			err = PTR_ERR(folios[i]);
 			idx = i - 1;
@@ -1496,21 +1499,37 @@ static int sanity_check_node_footer(struct f2fs_sb_info *sbi,
 					struct folio *folio, pgoff_t nid,
 					enum node_type ntype)
 {
-	if (unlikely(nid != nid_of_node(folio) ||
-		(ntype == NODE_TYPE_INODE && !IS_INODE(folio)) ||
-		(ntype == NODE_TYPE_XATTR &&
-		!f2fs_has_xattr_block(ofs_of_node(folio))) ||
-		time_to_inject(sbi, FAULT_INCONSISTENT_FOOTER))) {
-		f2fs_warn(sbi, "inconsistent node block, node_type:%d, nid:%lu, "
-			  "node_footer[nid:%u,ino:%u,ofs:%u,cpver:%llu,blkaddr:%u]",
-			  ntype, nid, nid_of_node(folio), ino_of_node(folio),
-			  ofs_of_node(folio), cpver_of_node(folio),
-			  next_blkaddr_of_node(folio));
-		set_sbi_flag(sbi, SBI_NEED_FSCK);
-		f2fs_handle_error(sbi, ERROR_INCONSISTENT_FOOTER);
-		return -EFSCORRUPTED;
+	if (unlikely(nid != nid_of_node(folio)))
+		goto out_err;
+
+	switch (ntype) {
+	case NODE_TYPE_INODE:
+		if (!IS_INODE(folio))
+			goto out_err;
+		break;
+	case NODE_TYPE_XATTR:
+		if (!f2fs_has_xattr_block(ofs_of_node(folio)))
+			goto out_err;
+		break;
+	case NODE_TYPE_NON_INODE:
+		if (IS_INODE(folio))
+			goto out_err;
+		break;
+	default:
+		break;
 	}
+	if (time_to_inject(sbi, FAULT_INCONSISTENT_FOOTER))
+		goto out_err;
 	return 0;
+out_err:
+	f2fs_warn(sbi, "inconsistent node block, node_type:%d, nid:%lu, "
+		  "node_footer[nid:%u,ino:%u,ofs:%u,cpver:%llu,blkaddr:%u]",
+		  ntype, nid, nid_of_node(folio), ino_of_node(folio),
+		  ofs_of_node(folio), cpver_of_node(folio),
+		  next_blkaddr_of_node(folio));
+	set_sbi_flag(sbi, SBI_NEED_FSCK);
+	f2fs_handle_error(sbi, ERROR_INCONSISTENT_FOOTER);
+	return -EFSCORRUPTED;
 }
 
 static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid,
@@ -1567,9 +1586,10 @@ out_put_err:
 	return ERR_PTR(err);
 }
 
-struct folio *f2fs_get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid)
+struct folio *f2fs_get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid,
+						enum node_type node_type)
 {
-	return __get_node_folio(sbi, nid, NULL, 0, NODE_TYPE_REGULAR);
+	return __get_node_folio(sbi, nid, NULL, 0, node_type);
 }
 
 struct folio *f2fs_get_inode_folio(struct f2fs_sb_info *sbi, pgoff_t ino)