From nobody Sat Feb 7 23:22:56 2026 Received: from air.basealt.ru (air.basealt.ru [193.43.8.18]) (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 5B0412236F4 for ; Mon, 10 Mar 2025 09:05:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.43.8.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741597507; cv=none; b=gxxfCC+DPFkqbpggZ4VUJYVcMe03C/FLHfjB7SqLrWi4fR7oEhvMH33Af4irz5ifLkFIiDUuOQfloWXkK0qQ7pUgTvXO+LrRisfTzr+PwHlrICOtAoecQ6MIg7IPs0uP6fiMvkdtafIpBYwvBwKTs0xCCqhnVqQ6sQPeTD2eYpQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741597507; c=relaxed/simple; bh=w3BR6QPDy9hnL6s+qjUkpTKXrUYFLvXNgLVLn6KL2M4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=tIIv4xuLZsYmThp/o7ymGUzuWwBRpMYEhsrV/7EN6MwFz1m0AuRZzFX4SZd1wdJKf2xxn+wCVxEqHkt38yL5GT+4MG1OvHzjXjG0iHBPKINOBgmxsmzrxgft32xAkY5g3a1xzr8eTxipK/sFP3SNh3OAYVCFfDZXAlO9fVha8MM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=altlinux.org; spf=pass smtp.mailfrom=altlinux.org; arc=none smtp.client-ip=193.43.8.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=altlinux.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=altlinux.org Received: from altlinux.malta.altlinux.ru (obninsk.basealt.ru [217.15.195.17]) (Authenticated sender: kovalevvv) by air.basealt.ru (Postfix) with ESMTPSA id C5D8123374; Mon, 10 Mar 2025 11:56:02 +0300 (MSK) From: Vasiliy Kovalev To: Dave Kleikamp , Edward Adam Davis , Rand Deeb , jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org Cc: lvc-project@linuxtesting.org, kovalev@altlinux.org Subject: [PATCH] jfs: validate AG parameters in dbMount() to prevent crashes Date: Mon, 10 Mar 2025 11:56:02 +0300 Message-Id: <20250310085602.953206-1-kovalev@altlinux.org> X-Mailer: git-send-email 2.33.8 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Validate db_agheight, db_agwidth, and db_agstart in dbMount to catch corrupted metadata early and avoid undefined behavior in dbAllocAG. Limits are derived from L2LPERCTL, LPERCTL/MAXAG, and CTLTREESIZE: - agheight: 0 to L2LPERCTL/2 (0 to 5) ensures shift (L2LPERCTL - 2*agheight) >=3D 0. - agwidth: 1 to min(LPERCTL/MAXAG, 2^(L2LPERCTL - 2*agheight)) ensures agperlev >=3D 1. - Ranges: 1-8 (agheight 0-3), 1-4 (agheight 4), 1 (agheight 5). - LPERCTL/MAXAG =3D 1024/128 =3D 8 limits leaves per AG; 2^(10 - 2*agheight) prevents division to 0. - agstart: 0 to CTLTREESIZE-1 - agwidth*(MAXAG-1) keeps ti within stree (size 1365). - Ranges: 0-1237 (agwidth 1), 0-348 (agwidth 8). UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:1400:9 shift exponent -335544310 is negative CPU: 0 UID: 0 PID: 5822 Comm: syz-executor130 Not tainted 6.14.0-rc5-syzkal= ler #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 02/= 12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468 dbAllocAG+0x1087/0x10b0 fs/jfs/jfs_dmap.c:1400 dbDiscardAG+0x352/0xa20 fs/jfs/jfs_dmap.c:1613 jfs_ioc_trim+0x45a/0x6b0 fs/jfs/jfs_discard.c:105 jfs_ioctl+0x2cd/0x3e0 fs/jfs/ioctl.c:131 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Cc: stable@vger.kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+fe8264911355151c487f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3Dfe8264911355151c487f Signed-off-by: Vasiliy Kovalev --- fs/jfs/jfs_dmap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 26e89d0c69b61..cfb21f15f5971 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -194,7 +194,11 @@ int dbMount(struct inode *ipbmap) !bmp->db_numag || (bmp->db_numag > MAXAG) || (bmp->db_maxag >=3D MAXAG) || (bmp->db_maxag < 0) || (bmp->db_agpref >=3D MAXAG) || (bmp->db_agpref < 0) || - !bmp->db_agwidth || + bmp->db_agheight < 0 || bmp->db_agheight > (L2LPERCTL >> 1) || + bmp->db_agwidth < 1 || bmp->db_agwidth > (LPERCTL / MAXAG) || + bmp->db_agwidth > (1 << (L2LPERCTL - (bmp->db_agheight << 1))) || + bmp->db_agstart < 0 || bmp->db_agstart > + (CTLTREESIZE - 1 - bmp->db_agwidth * (MAXAG - 1)) || (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG) || (bmp->db_agl2size < 0) || ((bmp->db_mapsize - 1) >> bmp->db_agl2size) > MAXAG) { --=20 2.42.2