From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC6A03B19AB for ; Fri, 24 Jul 2026 10:49:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784890155; cv=none; b=UWn6oTjMGZduGUW1KeUzJ+0gyA8nrodBSb0Th/N5qh2Zb8OYEAB4WDqF6WBggfOpfIP/pbb0UfXUFaRPCv6ZTmPNS5it8DWlfrkPM4tsUeoYfZLEC/fec7Nskt7UWta9oF9YN3xF/pjE3SOS16w155HuQb4MBtwpibFH1ko/V9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784890155; c=relaxed/simple; bh=ZizFG+0xmvAb9PF34+RPA75QGYM/cgjVOnh/Ffs9PZQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mrFkf+IoQFHofmgRQt+v+IXFlf82i+bZ/1pO6YkNC72bbwPxZ3piNgKtbTe40MpCT/+LNUMlruTnYU9YCqIJ7I+SNxXFs0jds9PrTAtanxZ6XY+JQCuCF4A5cHqakkjDp9FjHP433h3BDlqYjvmmGKdx3gVMDE8GEETv/tuzXck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CRVZYtx1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CRVZYtx1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C601A1F00AC4; Fri, 24 Jul 2026 10:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784890154; bh=I/qJkp6Hd6ntfVZvqWjbuK579diEXGTC9a3LcGMp8cM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CRVZYtx1t4hy6SvZNS1JpiVfbao1mr4Q9LqERXCCGVfdzZphxjjFbcmrnnxqOZtqD je0ox70jlHso3TULcxxdWHFpW4TwwVFzJGok4ndTf7wotod+ys9d0UmDh4j3clAxJt OzAkHNSQzFmnPeLJeT1y8jHVHlx4joV5fI91VE3tearkRC7WQdMfnfELNIvqIzYHV3 NfLZq6F9ycEB3I/ggm3xCNOFqgqq9q8gpO8reuWOLJuCDsmM6YQjVmFkBYj5F6/2s4 2wgmZpAIm7AP415cyPXtRWDhJ+yM6NLylplnxzdPf26O4T9pz5tyAl1MgBUjoOJpvE OaGmyuZtIjHgQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Michael Bommarito , Konstantin Komarov , Sasha Levin Subject: [PATCH 6.1.y 2/2] ntfs3: validate split-point offset in indx_insert_into_buffer Date: Fri, 24 Jul 2026 06:49:11 -0400 Message-ID: <20260724104911.3974416-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260724104911.3974416-1-sashal@kernel.org> References: <2026072048-smudge-reselect-d44b@gregkh> <20260724104911.3974416-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Michael Bommarito [ Upstream commit f1df9d771df47aa40de6d70949c28720ae1e430d ] indx_insert_into_buffer() computes used = used1 - to_copy - sp_size; memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off)); where sp and sp_size come from hdr_find_split(). hdr_find_split() walks entries by le16_to_cpu(e->size) without validating that each step stays within hdr->used or that the size field is at least sizeof(struct NTFS_DE). index_hdr_check(), the on-load gatekeeper, only validates header-level fields (used, total, de_off) and does not walk per-entry sizes. A crafted NTFS image whose leaf INDEX_HDR reports used == total but contains one interior NTFS_DE with size = 0xFFF0 therefore passes validation, descends to indx_insert_into_buffer() through the ntfs_create() -> indx_insert_entry() path, and makes hdr_find_split() return an sp whose sp_size (0xFFF0) greatly exceeds the remaining bytes in the buffer. The u32 subtraction underflows and the memmove count becomes a near-4-GiB value, producing an out-of-bounds kernel write that corrupts adjacent allocations and panics the kernel. Reproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a single 'touch' inside the mounted directory; crash site resolves to fs/ntfs3/index.c at the memmove. Trigger requires only local mount of an attacker-supplied filesystem image (USB, loopback, or removable media auto-mount). Reject the split whenever the chosen sp plus its declared size already extends past hdr1->used. This is the minimal fix; it preserves the existing hdr_find_split() contract and relies on the same out: cleanup path as the pre-existing error returns. A prior OOB read in the very same indx_insert_into_buffer() memmove was fixed in commit b8c44949044e ("fs/ntfs3: Fix OOB read in indx_insert_into_buffer") by tightening hdr_find_e(), but that fix does not cover the split-point size field path addressed here: sp is returned by hdr_find_split(), not hdr_find_e(), and the underflow is driven by sp->size rather than hdr->used exceeding hdr->total. Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block") Cc: stable@vger.kernel.org Reported-by: Michael Bommarito Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin --- fs/ntfs3/index.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c index e801bf16854de9..78de866b5ddce2 100644 --- a/fs/ntfs3/index.c +++ b/fs/ntfs3/index.c @@ -1834,6 +1834,20 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni, memcpy(up_e, sp, sp_size); used1 = le32_to_cpu(hdr1->used); + + /* + * hdr_find_split does not validate per-entry sizes, so a crafted + * NTFS_DE whose le16 size field is out of range can place sp such + * that (PtrOffset(hdr1, sp) + sp_size) exceeds used1. Without this + * guard the u32 'used = used1 - to_copy - sp_size' underflows and + * the subsequent memmove count becomes a near-4-GiB value, + * triggering an out-of-bounds kernel write. + */ + if (PtrOffset(hdr1, sp) + sp_size > used1) { + err = -EINVAL; + goto out; + } + hdr1_saved = kmemdup(hdr1, used1, GFP_NOFS); if (!hdr1_saved) { err = -ENOMEM; -- 2.53.0