linux-kernel - [PATCH 0/1] hfs: discuss to add offset/length validation in hfs_brec

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Message-Id: <20250818141734.8559-1-yang.chenzhi@vivo.com>
Date: Mon, 18 Aug 2025 22:17:33 +0800
From: Chenzhi Yang <yang.chenzhi@...o.com>
To: slava@...eyko.com,
	glaubitz@...sik.fu-berlin.de,
	frank.li@...o.com
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Yang Chenzhi <yang.chenzhi@...o.com>
Subject: [PATCH 0/1] hfs: discuss to add offset/length validation in hfs_brec_lenoff

From: Yang Chenzhi <yang.chenzhi@...o.com>

When running syzbot with a crafted HFS/HFS+ disk image containing
invalid record offsets or lengths, the filesystem may hang. For
example, in this case syzbot set the header’s second record offset
to 0x7f00 while node_size is 4096. HFS/HFS+ failed to detect this
fault, which eventually led to a crash.

Since HFS/HFS+ makes heavy use of hfs_brec_lenoff, adding manual
offset/length checks at every call site would be tedious and
error-prone.

Instead, it may be more robust to introduce validation directly
inside hfs_brec_lenoff (or at a similar central point), ensuring
that all callers can safely rely on the returned offset and length
without additional checks.

Yang Chenzhi (1):
  hfs: validate record offset in hfsplus_bmap_alloc

 fs/hfsplus/bnode.c      | 41 ----------------------------------------
 fs/hfsplus/btree.c      |  6 ++++++
 fs/hfsplus/hfsplus_fs.h | 42 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 41 deletions(-)

-- 
2.43.0