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 835E337417B for ; Sat, 15 Aug 2026 06:24:01 +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=1786775042; cv=none; b=SYIdwh9WrhYlnKH77qrS/SB8DcolXTPik3GVIHcf/X86onLcVRVfPFgxklhW0AywVkZtKJ44dobwRkk1hGf1yPOYviHx5RevuVb7XUMfVj67P7jlW/2rfhsGWEHuleDuRcEEPOilHfWVlyHtfHKCT9w3IMLQU4iMQ3K2+MFivqg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775042; c=relaxed/simple; bh=pzHr/JHsKEwbiy4L7eAO6A6Y67NjcWH2hlSC1su9J+s=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dwfQvI64gwHwi9m4QW2n2b9lQ2HEAo68go9pBcnMZ5EndJLbFMFFM8X98Q9ti47GQZTJiGVNf4bh+4EoytenO/ui9ZmACqaTdl7i0lsC4sJjaXGZFY10Fr8MQnItTFGUp33hQokaE+e/Wgd9EwrPlJQkRjhxz8rlcrseOCh5PDY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CK4Yebhi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CK4Yebhi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B18951F000E9; Sat, 15 Aug 2026 06:24:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775041; bh=Bs7p3npKDgKBVPXMtftJ8hEME2R06s2f2ysH76eOrW8=; h=From:To:Cc:Subject:Date:Reply-To; b=CK4Yebhi60eZwidxj8asG3NI7GUH7A/eP4CCYngkJ1jZ1drWrEPATT7RKMGMyv9tY GbP9uUKxmBJmFx8r8cMGJFKn8K8i1KguO2S4l4w13qKwXbHc97vFJ6Tm2am0u+Cxzf zHCyazKjsYlmkjs1y7Y6EnMjrbWo+UDkjWf2SNVg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-72353: ntfs: avoid stale runlist element dereference in fallocate Date: Sat, 15 Aug 2026 15:07:12 +0900 Message-ID: <2026081512-CVE-2026-72353-8629@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5060; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=hshTlv8uzp98v22PiAnsz6jy1ByuDlOLUcO7gJ+RvnU=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNDE8CG7+FzPimmXP92Qe9d7HGj1cuYqp6dKxd2vbOl CNv1kxk7YhlYRBkYpAVU2T5so3n6P6KQ4pehranYeawMoEMYeDiFICJPPZjmMNx+ueeluU9E0sq Xk+4fvWr1jbeTh+GBUdfxd2x8Vuvpb/df9ayU8vLNmzz4AUA X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: ntfs: avoid stale runlist element dereference in fallocate ntfs_attr_fallocate() allocates holes and delayed allocations inside initialized size by looking up the current runlist element under ni->runlist.lock. The returned struct runlist_element is only a borrowed pointer into ni->runlist.rl. A writer can replace and free that array after the read lock is dropped, so later reads of rl->lcn, rl->length and rl->vcn can touch freed memory. The buggy scenario involves two paths, with each column showing the order within that path: ntfs_attr_fallocate(): 1. Take ni->runlist.lock for read. 2. Get rl from ntfs_attr_find_vcn_nolock(). 3. Drop ni->runlist.lock. 4. Read rl->lcn, rl->length and rl->vcn. mmap page_mkwrite: 1. Enter ntfs_filemap_page_mkwrite(). 2. Reach __ntfs_write_iomap_begin() and ntfs_attr_map_cluster(). 3. Merge allocation state with ntfs_runlists_merge(). 4. Reallocate ni->runlist.rl in ntfs_rl_realloc(), freeing the old array. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in ntfs_attr_fallocate+0xbb8/0xd00 Call Trace: dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 ? ntfs_attr_fallocate+0xbb8/0xd00 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x20d/0x410 ? ntfs_attr_fallocate+0xbb8/0xd00 kasan_report+0xe0/0x110 ? ntfs_attr_fallocate+0xbb8/0xd00 ntfs_attr_fallocate+0xbb8/0xd00 ? lock_acquire+0x2b8/0x2f0 ? __pfx_ntfs_attr_fallocate+0x10/0x10 ? 0xffffffffc0000095 ? down_write+0x10d/0x1e0 ntfs_fallocate+0x5c9/0x1d00 ? __pfx_ntfs_fallocate+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_acquire+0x2b8/0x2f0 ? srso_alias_return_thunk+0x5/0xfbef5 ? selinux_file_permission+0x3a7/0x510 vfs_fallocate+0x29d/0xd30 __x64_sys_fallocate+0xc7/0x150 ? do_syscall_64+0x81/0x6a0 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Allocated by task 410: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kvmalloc_node_noprof+0x353/0x920 ntfs_rl_realloc+0x3f/0x110 ntfs_runlists_merge+0xaa3/0x3010 ntfs_attr_map_cluster+0x4e5/0xf80 ntfs_attr_fallocate+0x53f/0xd00 ntfs_fallocate+0x5c9/0x1d00 vfs_fallocate+0x29d/0xd30 __x64_sys_fallocate+0xc7/0x150 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 424: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 kfree+0x307/0x580 ntfs_rl_realloc+0x6f/0x110 ntfs_runlists_merge+0x7b1/0x3010 ntfs_attr_map_cluster+0x4e5/0xf80 __ntfs_write_iomap_begin+0x8cd/0x2280 iomap_iter+0x6de/0x11e0 iomap_page_mkwrite+0x391/0x650 ntfs_filemap_page_mkwrite+0x1ac/0x400 do_page_mkwrite+0x15c/0x280 __handle_mm_fault+0xd6d/0x1ca0 handle_mm_fault+0x19c/0x470 do_user_addr_fault+0x23b/0x9c0 exc_page_fault+0x5c/0xc0 asm_exc_page_fault+0x26/0x30 Fix this by copying the needed runlist fields while the read lock is still held and using only those scalar snapshots after unlocking. After the snapshot, ntfs_attr_map_cluster() can also find that the range is already mapped and return balloc=false. Only call ntfs_dio_zero_range() when new clusters were allocated, matching the write iomap path and preserving the zero-newly-allocated-holes behavior. The Linux kernel CVE team has assigned CVE-2026-72353 to this issue. Affected and fixed versions =========================== Issue introduced in 7.1 with commit 495e90fa334828d4119061e2726af51d0a0fb4ed and fixed in 7.1.5 with commit 3dd3e43f17cda174009a51fe668046ed7afef46a Issue introduced in 7.1 with commit 495e90fa334828d4119061e2726af51d0a0fb4ed and fixed in 7.2-rc3 with commit 88496c4ac5a6ade75619f4b1015706a8b924d50a Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-72353 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/ntfs/attrib.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/3dd3e43f17cda174009a51fe668046ed7afef46a https://git.kernel.org/stable/c/88496c4ac5a6ade75619f4b1015706a8b924d50a