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

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

[Chao Yu via Linux-f2fs-devel]

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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[f2fs-dev] [PATCH 2/2] f2fs: fix to do sanity check on node footer in {read, write}_end_io

[Chao Yu via Linux-f2fs-devel]

-----------[ cut here ]------------
kernel BUG at fs/f2fs/data.c:358!
Call Trace:
 <IRQ>
 blk_update_request+0x5eb/0xe70 block/blk-mq.c:987
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1149
 blk_complete_reqs block/blk-mq.c:1224 [inline]
 blk_done_softirq+0x107/0x160 block/blk-mq.c:1229
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>

In f2fs_write_end_io(), it detects there is inconsistency in between
node page index (nid) and footer.nid of node page.

If footer of node page is corrupted in fuzzed image, then we load corrupted
node page w/ async method, e.g. f2fs_ra_node_pages() or f2fs_ra_node_page(),
in where we won't do sanity check on node footer, once node page becomes
dirty, we will encounter this bug after node page writeback.

Cc: stable@kernel.org
Reported-by: syzbot+803dd716c4310d16ff3a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=803dd716c4310d16ff3a
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/data.c | 13 +++++++++++--
 fs/f2fs/f2fs.h | 11 +++++++++++
 fs/f2fs/node.c | 24 ++++++++++++++----------
 fs/f2fs/node.h |  8 --------
 4 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 775aa4f63aa3..07dcc0211824 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -150,6 +150,12 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
 			continue;
 		}
 
+		if (F2FS_F_SB(folio)->node_inode && is_node_folio(folio)) {
+			if (f2fs_sanity_check_node_footer(F2FS_F_SB(folio),
+				folio, folio->index, NODE_TYPE_REGULAR, true))
+				bio->bi_status = BLK_STS_IOERR;
+		}
+
 		dec_page_count(F2FS_F_SB(folio), __read_io_type(folio));
 		folio_end_read(folio, bio->bi_status == BLK_STS_OK);
 	}
@@ -352,8 +358,11 @@ static void f2fs_write_end_io(struct bio *bio)
 						STOP_CP_REASON_WRITE_FAIL);
 		}
 
-		f2fs_bug_on(sbi, is_node_folio(folio) &&
-				folio->index != nid_of_node(folio));
+		if (is_node_folio(folio)) {
+			f2fs_sanity_check_node_footer(sbi, folio,
+				folio->index, NODE_TYPE_REGULAR, true);
+			f2fs_bug_on(sbi, folio->index != nid_of_node(folio));
+		}
 
 		dec_page_count(sbi, type);
 		if (f2fs_in_warm_node_list(sbi, folio))
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b6e35fdd5fd3..839032a4da39 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1504,6 +1504,14 @@ enum f2fs_lookup_mode {
 	LOOKUP_AUTO,
 };
 
+/* For node type in __get_node_folio() */
+enum node_type {
+	NODE_TYPE_REGULAR,
+	NODE_TYPE_INODE,
+	NODE_TYPE_XATTR,
+	NODE_TYPE_NON_INODE,
+};
+
 static inline int f2fs_test_bit(unsigned int nr, char *addr);
 static inline void f2fs_set_bit(unsigned int nr, char *addr);
 static inline void f2fs_clear_bit(unsigned int nr, char *addr);
@@ -3849,6 +3857,9 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs);
 void f2fs_ra_node_page(struct f2fs_sb_info *sbi, nid_t nid);
 struct folio *f2fs_get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid,
 						enum node_type node_type);
+int f2fs_sanity_check_node_footer(struct f2fs_sb_info *sbi,
+					struct folio *folio, pgoff_t nid,
+					enum node_type ntype, bool in_irq);
 struct folio *f2fs_get_inode_folio(struct f2fs_sb_info *sbi, pgoff_t ino);
 struct folio *f2fs_get_xnode_folio(struct f2fs_sb_info *sbi, pgoff_t xnid);
 int f2fs_move_node_folio(struct folio *node_folio, int gc_type);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 2bb9e6d35080..e70c970a3047 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1500,9 +1500,9 @@ void f2fs_ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
 	f2fs_folio_put(afolio, err ? true : false);
 }
 
-static int sanity_check_node_footer(struct f2fs_sb_info *sbi,
+int f2fs_sanity_check_node_footer(struct f2fs_sb_info *sbi,
 					struct folio *folio, pgoff_t nid,
-					enum node_type ntype)
+					enum node_type ntype, bool in_irq)
 {
 	bool is_inode;
 
@@ -1544,13 +1544,16 @@ static int sanity_check_node_footer(struct f2fs_sb_info *sbi,
 		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);
+	f2fs_warn_ratelimited(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));
+	if (in_irq)
+		f2fs_handle_error_async(sbi, ERROR_INCONSISTENT_FOOTER);
+	else
+		f2fs_handle_error(sbi, ERROR_INCONSISTENT_FOOTER);
 	return -EFSCORRUPTED;
 }
 
@@ -1595,7 +1598,7 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid,
 		goto out_err;
 	}
 page_hit:
-	err = sanity_check_node_footer(sbi, folio, nid, ntype);
+	err = f2fs_sanity_check_node_footer(sbi, folio, nid, ntype, false);
 	if (!err)
 		return folio;
 out_err:
@@ -1769,7 +1772,8 @@ 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);
 
-	if (sanity_check_node_footer(sbi, folio, nid, NODE_TYPE_REGULAR)) {
+	if (f2fs_sanity_check_node_footer(sbi, folio, nid,
+					NODE_TYPE_REGULAR, false)) {
 		f2fs_handle_critical_error(sbi, STOP_CP_REASON_CORRUPTED_NID);
 		goto redirty_out;
 	}
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index 9cb8dcf8d417..824ac9f0e6e4 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -52,14 +52,6 @@ enum {
 	IS_PREALLOC,		/* nat entry is preallocated */
 };
 
-/* For node type in __get_node_folio() */
-enum node_type {
-	NODE_TYPE_REGULAR,
-	NODE_TYPE_INODE,
-	NODE_TYPE_XATTR,
-	NODE_TYPE_NON_INODE,
-};
-
 /*
  * For node information
  */
-- 
2.49.0



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