From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3AF2A2FD681 for ; Sun, 12 Apr 2026 18:11:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776017481; cv=none; b=dmnhjUoZFzPA4eI+3R4pQ9ojl8ZY5XNdj9e8lt8dGh7IZS7H+55ohB82wSXd8Js4aYC+pma/E1j7++JT0WYDE/5RJSgTUlvm8Jf0RF9IRVCjlM3tY9OJfdBlbMSMUWX4Ofn57prpGMbe6YgOJhI/pKrzmyvcjkeGkBwhQ2GzE8U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776017481; c=relaxed/simple; bh=uNLOIUDbvaQofJYYqEJj4onsRaPlCfkVqHsTjY02OoE=; h=Date:To:From:Subject:Message-Id; b=VhC91cr6WCSgI+dePjOwRibBY2CXSHjZKcphkfPfvQwhK877ZnZyYJVino4C5tF237lNmtAuJnMKzk/b9SBdqXEp57U2GWO2yPgN25KqQ3QX3Ipg+lC3AVQtV/tXPsDwaWKrIWylJWbQ2DBX1UfJYhQl9bUj0LtTPnt7m/puuA8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Qx6RwNbD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Qx6RwNbD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EC54C19424; Sun, 12 Apr 2026 18:11:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1776017480; bh=uNLOIUDbvaQofJYYqEJj4onsRaPlCfkVqHsTjY02OoE=; h=Date:To:From:Subject:From; b=Qx6RwNbDgN1ffeC7c0vHKKJj6mSy7uhYCGnuMXR2PkMtBehE3QAynsTK/h4PjyeSU ydk8U50yP1yF2qoacG8nnZawvQD8iU9uGcyKVtMzfXbPI2qIaPX7ebIaMGYpVDXaYc tdAhN84PVZ2bt1YSFw7V1MX0pdvNSqIyr6o8FRlg= Date: Sun, 12 Apr 2026 11:11:17 -0700 To: mm-commits@vger.kernel.org,piaojun@huawei.com,mark@fasheh.com,junxiao.bi@oracle.com,joseph.qi@linux.alibaba.com,jlbec@evilplan.org,heming.zhao@suse.com,gechangwei@live.cn,gality369@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + ocfs2-validate-bg_bits-during-freefrag-scan.patch added to mm-nonmm-unstable branch Message-Id: <20260412181120.3EC54C19424@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: ocfs2: validate bg_bits during freefrag scan has been added to the -mm mm-nonmm-unstable branch. Its filename is ocfs2-validate-bg_bits-during-freefrag-scan.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-validate-bg_bits-during-freefrag-scan.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: ZhengYuan Huang Subject: ocfs2: validate bg_bits during freefrag scan Date: Fri, 10 Apr 2026 11:42:20 +0800 [BUG] A crafted filesystem can trigger an out-of-bounds bitmap walk when OCFS2_IOC_INFO is issued with OCFS2_INFO_FL_NON_COHERENT. BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: use-after-free in test_bit_le include/asm-generic/bitops/le.h:21 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] BUG: KASAN: use-after-free in ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 Read of size 8 at addr ffff888031bce000 by task syz.0.636/1435 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xd1/0x650 mm/kasan/report.c:482 kasan_report+0xfb/0x140 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x11c/0x200 mm/kasan/generic.c:200 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] test_bit_le include/asm-generic/bitops/le.h:21 [inline] ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline] ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline] ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline] ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754 ocfs2_info_handle+0x18d/0x2a0 fs/ocfs2/ioctl.c:828 ocfs2_ioctl+0x632/0x6e0 fs/ocfs2/ioctl.c:913 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583 ... [CAUSE] ocfs2_info_freefrag_scan_chain() uses on-disk bg_bits directly as the bitmap scan limit. The coherent path reads group descriptors through ocfs2_read_group_descriptor(), which validates the descriptor before use. The non-coherent path uses ocfs2_read_blocks_sync() instead and skips that validation, so an impossible bg_bits value can drive the bitmap walk past the end of the block. [FIX] Compute the bitmap capacity from the filesystem format with ocfs2_group_bitmap_size(), report descriptors whose bg_bits exceeds that limit, and clamp the scan to the computed capacity. This keeps the freefrag report going while avoiding reads beyond the buffer. Link: https://lkml.kernel.org/r/20260410034220.3825769-1-gality369@gmail.com Fixes: d24a10b9f8ed ("Ocfs2: Add a new code 'OCFS2_INFO_FREEFRAG' for o2info ioctl.") Signed-off-by: ZhengYuan Huang Reviewed-by: Heming Zhao Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Jun Piao Cc: Heming Zhao Signed-off-by: Andrew Morton --- fs/ocfs2/ioctl.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) --- a/fs/ocfs2/ioctl.c~ocfs2-validate-bg_bits-during-freefrag-scan +++ a/fs/ocfs2/ioctl.c @@ -441,13 +441,16 @@ static int ocfs2_info_freefrag_scan_chai struct buffer_head *bh = NULL; struct ocfs2_group_desc *bg = NULL; - unsigned int max_bits, num_clusters; + unsigned int max_bits, max_bitmap_bits, num_clusters; unsigned int offset = 0, cluster, chunk; unsigned int chunk_free, last_chunksize = 0; if (!le32_to_cpu(rec->c_free)) goto bail; + max_bitmap_bits = 8 * ocfs2_group_bitmap_size(osb->sb, 0, + osb->s_feature_incompat); + do { if (!bg) blkno = le64_to_cpu(rec->c_blkno); @@ -479,6 +482,19 @@ static int ocfs2_info_freefrag_scan_chai continue; max_bits = le16_to_cpu(bg->bg_bits); + + /* + * Non-coherent scans read raw blocks and do not get the + * bg_bits validation from + * ocfs2_read_group_descriptor(). + */ + if (max_bits > max_bitmap_bits) { + mlog(ML_ERROR, + "Group desc #%llu has %u bits, max bitmap bits %u\n", + (unsigned long long)blkno, max_bits, max_bitmap_bits); + max_bits = max_bitmap_bits; + } + offset = 0; for (chunk = 0; chunk < chunks_in_group; chunk++) { _ Patches currently in -mm which might be from gality369@gmail.com are ocfs2-validate-bg_list-extent-bounds-in-discontig-groups.patch ocfs2-handle-invalid-dinode-in-ocfs2_group_extend.patch ocfs2-fix-listxattr-handling-when-the-buffer-is-full.patch ocfs2-validate-bg_bits-during-freefrag-scan.patch