[f2fs-dev] [PATCH AUTOSEL 6.6 1/7] f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

[f2fs-dev] [PATCH AUTOSEL 6.6 1/7] f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

[Sasha Levin]

From: Chao Yu <chao@kernel.org>

[ Upstream commit fc01008c92f40015aeeced94750855a7111b6929 ]

syzbot reports a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/inline.c:258!
CPU: 1 PID: 34 Comm: kworker/u8:2 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0
RIP: 0010:f2fs_write_inline_data+0x781/0x790 fs/f2fs/inline.c:258
Call Trace:
 f2fs_write_single_data_page+0xb65/0x1d60 fs/f2fs/data.c:2834
 f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline]
 __f2fs_write_data_pages fs/f2fs/data.c:3288 [inline]
 f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3315
 do_writepages+0x35b/0x870 mm/page-writeback.c:2612
 __writeback_single_inode+0x165/0x10b0 fs/fs-writeback.c:1650
 writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941
 wb_writeback+0x457/0xce0 fs/fs-writeback.c:2117
 wb_do_writeback fs/fs-writeback.c:2264 [inline]
 wb_workfn+0x410/0x1090 fs/fs-writeback.c:2304
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The root cause is: inline_data inode can be fuzzed, so that there may
be valid blkaddr in its direct node, once f2fs triggers background GC
to migrate the block, it will hit f2fs_bug_on() during dirty page
writeback.

Let's add sanity check on F2FS_INLINE_DATA flag in inode during GC,
so that, it can forbid migrating inline_data inode's data block for
fixing.

Reported-by: syzbot+848062ba19c8782ca5c8@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/000000000000d103ce06174d7ec3@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/gc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 3f0632dd9d2e6..ca4249938337c 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1560,6 +1560,16 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 				continue;
 			}
 
+			if (f2fs_has_inline_data(inode)) {
+				iput(inode);
+				set_sbi_flag(sbi, SBI_NEED_FSCK);
+				f2fs_err_ratelimited(sbi,
+					"inode %lx has both inline_data flag and "
+					"data block, nid=%u, ofs_in_node=%u",
+					inode->i_ino, dni.nid, ofs_in_node);
+				continue;
+			}
+
 			err = f2fs_gc_pinned_control(inode, gc_type, segno);
 			if (err == -EAGAIN) {
 				iput(inode);
-- 
2.43.0



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[f2fs-dev] [PATCH AUTOSEL 6.6 2/7] f2fs: fix to do sanity check on blocks for inline_data inode

[Sasha Levin]

From: Chao Yu <chao@kernel.org>

[ Upstream commit c240c87bcd44a1a2375fc8ef8c645d1f1fe76466 ]

inode can be fuzzed, so it can has F2FS_INLINE_DATA flag and valid
i_blocks/i_nid value, this patch supports to do extra sanity check
to detect such corrupted state.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/f2fs.h   |  2 +-
 fs/f2fs/inline.c | 20 +++++++++++++++++++-
 fs/f2fs/inode.c  |  2 +-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c7e717ab09000..1252d57228dc6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4143,7 +4143,7 @@ extern struct kmem_cache *f2fs_inode_entry_slab;
  * inline.c
  */
 bool f2fs_may_inline_data(struct inode *inode);
-bool f2fs_sanity_check_inline_data(struct inode *inode);
+bool f2fs_sanity_check_inline_data(struct inode *inode, struct page *ipage);
 bool f2fs_may_inline_dentry(struct inode *inode);
 void f2fs_do_read_inline_data(struct page *page, struct page *ipage);
 void f2fs_truncate_inline_inode(struct inode *inode,
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 2fe25619ccb5f..529b88f0b8cc5 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -33,11 +33,29 @@ bool f2fs_may_inline_data(struct inode *inode)
 	return !f2fs_post_read_required(inode);
 }
 
-bool f2fs_sanity_check_inline_data(struct inode *inode)
+static bool inode_has_blocks(struct inode *inode, struct page *ipage)
+{
+	struct f2fs_inode *ri = F2FS_INODE(ipage);
+	int i;
+
+	if (F2FS_HAS_BLOCKS(inode))
+		return true;
+
+	for (i = 0; i < DEF_NIDS_PER_INODE; i++) {
+		if (ri->i_nid[i])
+			return true;
+	}
+	return false;
+}
+
+bool f2fs_sanity_check_inline_data(struct inode *inode, struct page *ipage)
 {
 	if (!f2fs_has_inline_data(inode))
 		return false;
 
+	if (inode_has_blocks(inode, ipage))
+		return false;
+
 	if (!support_inline_data(inode))
 		return true;
 
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index ab2eecd986ec5..abe2f5f043b0d 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -343,7 +343,7 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
 		}
 	}
 
-	if (f2fs_sanity_check_inline_data(inode)) {
+	if (f2fs_sanity_check_inline_data(inode, node_page)) {
 		f2fs_warn(sbi, "%s: inode (ino=%lx, mode=%u) should not have inline_data, run fsck to fix",
 			  __func__, inode->i_ino, inode->i_mode);
 		return false;
-- 
2.43.0



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[f2fs-dev] [PATCH AUTOSEL 6.6 3/7] f2fs: fix to cover read extent cache access with lock

[Sasha Levin]

From: Chao Yu <chao@kernel.org>

[ Upstream commit d7409b05a64f212735f0d33f5f1602051a886eab ]

syzbot reports a f2fs bug as below:

BUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46
Read of size 4 at addr ffff8880739ab220 by task syz-executor200/5097

CPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46
 do_read_inode fs/f2fs/inode.c:509 [inline]
 f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560
 f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237
 generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413
 exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444
 exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584
 do_handle_to_path fs/fhandle.c:155 [inline]
 handle_to_path fs/fhandle.c:210 [inline]
 do_handle_open+0x495/0x650 fs/fhandle.c:226
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

We missed to cover sanity_check_extent_cache() w/ extent cache lock,
so, below race case may happen, result in use after free issue.

- f2fs_iget
 - do_read_inode
  - f2fs_init_read_extent_tree
  : add largest extent entry in to cache
					- shrink
					 - f2fs_shrink_read_extent_tree
					  - __shrink_extent_tree
					   - __detach_extent_node
					   : drop largest extent entry
  - sanity_check_extent_cache
  : access et->largest w/o lock

let's refactor sanity_check_extent_cache() to avoid extent cache access
and call it before f2fs_init_read_extent_tree() to fix this issue.

Reported-by: syzbot+74ebe2104433e9dc610d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/00000000000009beea061740a531@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/extent_cache.c | 48 +++++++++++++++++-------------------------
 fs/f2fs/f2fs.h         |  2 +-
 fs/f2fs/inode.c        | 10 ++++-----
 3 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index ad8dfac73bd44..6a9a470345bfc 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -19,34 +19,24 @@
 #include "node.h"
 #include <trace/events/f2fs.h>
 
-bool sanity_check_extent_cache(struct inode *inode)
+bool sanity_check_extent_cache(struct inode *inode, struct page *ipage)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct f2fs_inode_info *fi = F2FS_I(inode);
-	struct extent_tree *et = fi->extent_tree[EX_READ];
-	struct extent_info *ei;
-
-	if (!et)
-		return true;
+	struct f2fs_extent *i_ext = &F2FS_INODE(ipage)->i_ext;
+	struct extent_info ei;
 
-	ei = &et->largest;
-	if (!ei->len)
-		return true;
+	get_read_extent_info(&ei, i_ext);
 
-	/* Let's drop, if checkpoint got corrupted. */
-	if (is_set_ckpt_flags(sbi, CP_ERROR_FLAG)) {
-		ei->len = 0;
-		et->largest_updated = true;
+	if (!ei.len)
 		return true;
-	}
 
-	if (!f2fs_is_valid_blkaddr(sbi, ei->blk, DATA_GENERIC_ENHANCE) ||
-	    !f2fs_is_valid_blkaddr(sbi, ei->blk + ei->len - 1,
+	if (!f2fs_is_valid_blkaddr(sbi, ei.blk, DATA_GENERIC_ENHANCE) ||
+	    !f2fs_is_valid_blkaddr(sbi, ei.blk + ei.len - 1,
 					DATA_GENERIC_ENHANCE)) {
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
 		f2fs_warn(sbi, "%s: inode (ino=%lx) extent info [%u, %u, %u] is incorrect, run fsck to fix",
 			  __func__, inode->i_ino,
-			  ei->blk, ei->fofs, ei->len);
+			  ei.blk, ei.fofs, ei.len);
 		return false;
 	}
 	return true;
@@ -395,24 +385,22 @@ void f2fs_init_read_extent_tree(struct inode *inode, struct page *ipage)
 
 	if (!__may_extent_tree(inode, EX_READ)) {
 		/* drop largest read extent */
-		if (i_ext && i_ext->len) {
+		if (i_ext->len) {
 			f2fs_wait_on_page_writeback(ipage, NODE, true, true);
 			i_ext->len = 0;
 			set_page_dirty(ipage);
 		}
-		goto out;
+		set_inode_flag(inode, FI_NO_EXTENT);
+		return;
 	}
 
 	et = __grab_extent_tree(inode, EX_READ);
 
-	if (!i_ext || !i_ext->len)
-		goto out;
-
 	get_read_extent_info(&ei, i_ext);
 
 	write_lock(&et->lock);
-	if (atomic_read(&et->node_cnt))
-		goto unlock_out;
+	if (atomic_read(&et->node_cnt) || !ei.len)
+		goto skip;
 
 	en = __attach_extent_node(sbi, et, &ei, NULL,
 				&et->root.rb_root.rb_node, true);
@@ -424,11 +412,13 @@ void f2fs_init_read_extent_tree(struct inode *inode, struct page *ipage)
 		list_add_tail(&en->list, &eti->extent_list);
 		spin_unlock(&eti->extent_lock);
 	}
-unlock_out:
+skip:
+	/* Let's drop, if checkpoint got corrupted. */
+	if (f2fs_cp_error(sbi)) {
+		et->largest.len = 0;
+		et->largest_updated = true;
+	}
 	write_unlock(&et->lock);
-out:
-	if (!F2FS_I(inode)->extent_tree[EX_READ])
-		set_inode_flag(inode, FI_NO_EXTENT);
 }
 
 void f2fs_init_age_extent_tree(struct inode *inode)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1252d57228dc6..c70f1314155f5 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4184,7 +4184,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *sbi);
 /*
  * extent_cache.c
  */
-bool sanity_check_extent_cache(struct inode *inode);
+bool sanity_check_extent_cache(struct inode *inode, struct page *ipage);
 void f2fs_init_extent_tree(struct inode *inode);
 void f2fs_drop_extent_tree(struct inode *inode);
 void f2fs_destroy_extent_node(struct inode *inode);
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index abe2f5f043b0d..dd7c0b4749e41 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -508,16 +508,16 @@ static int do_read_inode(struct inode *inode)
 
 	init_idisk_time(inode);
 
-	/* Need all the flag bits */
-	f2fs_init_read_extent_tree(inode, node_page);
-	f2fs_init_age_extent_tree(inode);
-
-	if (!sanity_check_extent_cache(inode)) {
+	if (!sanity_check_extent_cache(inode, node_page)) {
 		f2fs_put_page(node_page, 1);
 		f2fs_handle_error(sbi, ERROR_CORRUPTED_INODE);
 		return -EFSCORRUPTED;
 	}
 
+	/* Need all the flag bits */
+	f2fs_init_read_extent_tree(inode, node_page);
+	f2fs_init_age_extent_tree(inode);
+
 	f2fs_put_page(node_page, 1);
 
 	stat_inc_inline_xattr(inode);
-- 
2.43.0



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