[PATCH AUTOSEL 5.4 06/14] hfs: add missing clean-up in hfs_fill_super

[PATCH AUTOSEL 5.4 06/14] hfs: add missing clean-up in hfs_fill_super

[Sasha Levin]

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

[ Upstream commit 16ee572eaf0d09daa4c8a755fdb71e40dbf8562d ]

Patch series "hfs: fix various errors", v2.

This series ultimately aims to address a lockdep warning in
hfs_find_init reported by Syzbot [1].

The work done for this led to the discovery of another bug, and the
Syzkaller repro test also reveals an invalid memory access error after
clearing the lockdep warning.  Hence, this series is broken up into
three patches:

1. Add a missing call to hfs_find_exit for an error path in
   hfs_fill_super

2. Fix memory mapping in hfs_bnode_read by fixing calls to kmap

3. Add lock nesting notation to tell lockdep that the observed locking
   hierarchy is safe

This patch (of 3):

Before exiting hfs_fill_super, the struct hfs_find_data used in
hfs_find_init should be passed to hfs_find_exit to be cleaned up, and to
release the lock held on the btree.

The call to hfs_find_exit is missing from an error path.  We add it back
in by consolidating calls to hfs_find_exit for error paths.

Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1]
Link: https://lkml.kernel.org/r/20210701030756.58760-1-desmondcheongzx@gmail.com
Link: https://lkml.kernel.org/r/20210701030756.58760-2-desmondcheongzx@gmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/super.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index c33324686d89..bcf820ce0e02 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -421,14 +421,12 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!res) {
 		if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
 			res =  -EIO;
-			goto bail;
+			goto bail_hfs_find;
 		}
 		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
 	}
-	if (res) {
-		hfs_find_exit(&fd);
-		goto bail_no_root;
-	}
+	if (res)
+		goto bail_hfs_find;
 	res = -EINVAL;
 	root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
 	hfs_find_exit(&fd);
@@ -444,6 +442,8 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 	/* everything's okay */
 	return 0;
 
+bail_hfs_find:
+	hfs_find_exit(&fd);
 bail_no_root:
 	pr_err("get root inode failed\n");
 bail:
-- 
2.30.2

[PATCH AUTOSEL 5.4 07/14] hfs: fix high memory mapping in hfs_bnode_read

[Sasha Levin]

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

[ Upstream commit 54a5ead6f5e2b47131a7385d0c0af18e7b89cb02 ]

Pages that we read in hfs_bnode_read need to be kmapped into kernel
address space.  However, currently only the 0th page is kmapped.  If the
given offset + length exceeds this 0th page, then we have an invalid
memory access.

To fix this, we kmap relevant pages one by one and copy their relevant
portions of data.

An example of invalid memory access occurring without this fix can be seen
in the following crash report:

  ==================================================================
  BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline]
  BUG: KASAN: use-after-free in hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26
  Read of size 2 at addr ffff888125fdcffe by task syz-executor5/4634

  CPU: 0 PID: 4634 Comm: syz-executor5 Not tainted 5.13.0-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:79 [inline]
   dump_stack+0x195/0x1f8 lib/dump_stack.c:120
   print_address_description.constprop.0+0x1d/0x110 mm/kasan/report.c:233
   __kasan_report mm/kasan/report.c:419 [inline]
   kasan_report.cold+0x7b/0xd4 mm/kasan/report.c:436
   check_region_inline mm/kasan/generic.c:180 [inline]
   kasan_check_range+0x154/0x1b0 mm/kasan/generic.c:186
   memcpy+0x24/0x60 mm/kasan/shadow.c:65
   memcpy include/linux/fortify-string.h:191 [inline]
   hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26
   hfs_bnode_read_u16 fs/hfs/bnode.c:34 [inline]
   hfs_bnode_find+0x880/0xcc0 fs/hfs/bnode.c:365
   hfs_brec_find+0x2d8/0x540 fs/hfs/bfind.c:126
   hfs_brec_read+0x27/0x120 fs/hfs/bfind.c:165
   hfs_cat_find_brec+0x19a/0x3b0 fs/hfs/catalog.c:194
   hfs_fill_super+0xc13/0x1460 fs/hfs/super.c:419
   mount_bdev+0x331/0x3f0 fs/super.c:1368
   hfs_mount+0x35/0x40 fs/hfs/super.c:457
   legacy_get_tree+0x10c/0x220 fs/fs_context.c:592
   vfs_get_tree+0x93/0x300 fs/super.c:1498
   do_new_mount fs/namespace.c:2905 [inline]
   path_mount+0x13f5/0x20e0 fs/namespace.c:3235
   do_mount fs/namespace.c:3248 [inline]
   __do_sys_mount fs/namespace.c:3456 [inline]
   __se_sys_mount fs/namespace.c:3433 [inline]
   __x64_sys_mount+0x2b8/0x340 fs/namespace.c:3433
   do_syscall_64+0x37/0xc0 arch/x86/entry/common.c:47
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  RIP: 0033:0x45e63a
  Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 88 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
  RSP: 002b:00007f9404d410d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
  RAX: ffffffffffffffda RBX: 0000000020000248 RCX: 000000000045e63a
  RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f9404d41120
  RBP: 00007f9404d41120 R08: 00000000200002c0 R09: 0000000020000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
  R13: 0000000000000003 R14: 00000000004ad5d8 R15: 0000000000000000

  The buggy address belongs to the page:
  page:00000000dadbcf3e refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x125fdc
  flags: 0x2fffc0000000000(node=0|zone=2|lastcpupid=0x3fff)
  raw: 02fffc0000000000 ffffea000497f748 ffffea000497f6c8 0000000000000000
  raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888125fdce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff888125fdcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  >ffff888125fdcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                  ^
   ffff888125fdd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff888125fdd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ==================================================================

Link: https://lkml.kernel.org/r/20210701030756.58760-3-desmondcheongzx@gmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/bnode.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c
index b63a4df7327b..c0a73a6ffb28 100644
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -15,16 +15,31 @@
 
 #include "btree.h"
 
-void hfs_bnode_read(struct hfs_bnode *node, void *buf,
-		int off, int len)
+void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
 {
 	struct page *page;
+	int pagenum;
+	int bytes_read;
+	int bytes_to_read;
+	void *vaddr;
 
 	off += node->page_offset;
-	page = node->page[0];
+	pagenum = off >> PAGE_SHIFT;
+	off &= ~PAGE_MASK; /* compute page offset for the first page */
 
-	memcpy(buf, kmap(page) + off, len);
-	kunmap(page);
+	for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
+		if (pagenum >= node->tree->pages_per_bnode)
+			break;
+		page = node->page[pagenum];
+		bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
+
+		vaddr = kmap_atomic(page);
+		memcpy(buf + bytes_read, vaddr + off, bytes_to_read);
+		kunmap_atomic(vaddr);
+
+		pagenum++;
+		off = 0; /* page offset only applies to the first page */
+	}
 }
 
 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
-- 
2.30.2

[PATCH AUTOSEL 5.4 08/14] hfs: add lock nesting notation to hfs_find_init

[Sasha Levin]

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

[ Upstream commit b3b2177a2d795e35dc11597b2609eb1e7e57e570 ]

Syzbot reports a possible recursive lock in [1].

This happens due to missing lock nesting information.  From the logs, we
see that a call to hfs_fill_super is made to mount the hfs filesystem.
While searching for the root inode, the lock on the catalog btree is
grabbed.  Then, when the parent of the root isn't found, a call to
__hfs_bnode_create is made to create the parent of the root.  This
eventually leads to a call to hfs_ext_read_extent which grabs a lock on
the extents btree.

Since the order of locking is catalog btree -> extents btree, this lock
hierarchy does not lead to a deadlock.

To tell lockdep that this locking is safe, we add nesting notation to
distinguish between catalog btrees, extents btrees, and attributes
btrees (for HFS+).  This has already been done in hfsplus.

Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1]
Link: https://lkml.kernel.org/r/20210701030756.58760-4-desmondcheongzx@gmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reported-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com
Tested-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/bfind.c | 14 +++++++++++++-
 fs/hfs/btree.h |  7 +++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index 4af318fbda77..ef9498a6e88a 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -25,7 +25,19 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
 	fd->key = ptr + tree->max_key_len + 2;
 	hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n",
 		tree->cnid, __builtin_return_address(0));
-	mutex_lock(&tree->tree_lock);
+	switch (tree->cnid) {
+	case HFS_CAT_CNID:
+		mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX);
+		break;
+	case HFS_EXT_CNID:
+		mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX);
+		break;
+	case HFS_ATTR_CNID:
+		mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
+		break;
+	default:
+		return -EINVAL;
+	}
 	return 0;
 }
 
diff --git a/fs/hfs/btree.h b/fs/hfs/btree.h
index dcc2aab1b2c4..25ac9a8bb57a 100644
--- a/fs/hfs/btree.h
+++ b/fs/hfs/btree.h
@@ -13,6 +13,13 @@ typedef int (*btree_keycmp)(const btree_key *, const btree_key *);
 
 #define NODE_HASH_SIZE  256
 
+/* B-tree mutex nested subclasses */
+enum hfs_btree_mutex_classes {
+	CATALOG_BTREE_MUTEX,
+	EXTENTS_BTREE_MUTEX,
+	ATTR_BTREE_MUTEX,
+};
+
 /* A HFS BTree held in memory */
 struct hfs_btree {
 	struct super_block *sb;
-- 
2.30.2

[PATCH AUTOSEL 5.4 12/14] iomap: remove the length variable in iomap_seek_data

[Sasha Levin]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 3ac1d426510f97ace05093ae9f2f710d9cbe6215 ]

The length variable is rather pointless given that it can be trivially
deduced from offset and size.  Also the initial calculation can lead
to KASAN warnings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Leizhen (ThunderTown) <thunder.leizhen@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/iomap/seek.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
index c04bad4b2b43..c61b889235b3 100644
--- a/fs/iomap/seek.c
+++ b/fs/iomap/seek.c
@@ -186,27 +186,23 @@ loff_t
 iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
 {
 	loff_t size = i_size_read(inode);
-	loff_t length = size - offset;
 	loff_t ret;
 
 	/* Nothing to be found before or beyond the end of the file. */
 	if (offset < 0 || offset >= size)
 		return -ENXIO;
 
-	while (length > 0) {
-		ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
-				  &offset, iomap_seek_data_actor);
+	while (offset < size) {
+		ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
+				  ops, &offset, iomap_seek_data_actor);
 		if (ret < 0)
 			return ret;
 		if (ret == 0)
-			break;
-
+			return offset;
 		offset += ret;
-		length -= ret;
 	}
 
-	if (length <= 0)
-		return -ENXIO;
-	return offset;
+	/* We've reached the end of the file without finding data */
+	return -ENXIO;
 }
 EXPORT_SYMBOL_GPL(iomap_seek_data);
-- 
2.30.2

[PATCH AUTOSEL 5.4 13/14] iomap: remove the length variable in iomap_seek_hole

[Sasha Levin]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 49694d14ff68fa4b5f86019dbcfb44a8bd213e58 ]

The length variable is rather pointless given that it can be trivially
deduced from offset and size.  Also the initial calculation can lead
to KASAN warnings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Leizhen (ThunderTown) <thunder.leizhen@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/iomap/seek.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
index c61b889235b3..10c4c1e80124 100644
--- a/fs/iomap/seek.c
+++ b/fs/iomap/seek.c
@@ -140,23 +140,20 @@ loff_t
 iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
 {
 	loff_t size = i_size_read(inode);
-	loff_t length = size - offset;
 	loff_t ret;
 
 	/* Nothing to be found before or beyond the end of the file. */
 	if (offset < 0 || offset >= size)
 		return -ENXIO;
 
-	while (length > 0) {
-		ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
-				  &offset, iomap_seek_hole_actor);
+	while (offset < size) {
+		ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
+				  ops, &offset, iomap_seek_hole_actor);
 		if (ret < 0)
 			return ret;
 		if (ret == 0)
 			break;
-
 		offset += ret;
-		length -= ret;
 	}
 
 	return offset;
-- 
2.30.2