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 792AB3264EB for ; Wed, 24 Jun 2026 16:36:39 +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=1782319002; cv=none; b=S2f7EziLj43/Kt0SH5gClaPor20F8yo2+9bxdtho1Dny45L4HBFy3TdBWTbKaxkiaTRQ3rbLbf+dg+wf1HPDiU5HiNUKMkIVym/1F0O591z6PX6xEk9Vp48pL6siHht7RG4qnrewxs3kImyyvVPzHb1XexlgOwfNJLXqUMW1KLw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782319002; c=relaxed/simple; bh=Y7GY7XZ+19a3jSryIPWewlFHJwEJakiFQcHW4WbNAQ8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pW/moHmb4JJJRze0W8V2pqUdYABsEnOFN/zoz52wSpN+b0yn4p8d1g7UaGShNsACz0uuF1egKUmgh+ovp+S2nz8ie3R2FJcjUK9Km9Ryf2OL0g2h4r0Aqnc7xTvKgvM9nRlRjY/jxCsfRTqn8uJttLIQRaqwKB2LCEbHFx0grSw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PtpcEpzH; 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="PtpcEpzH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59BCB1F00A3E; Wed, 24 Jun 2026 16:36:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782318999; bh=+lXSyIJvfPdi1+zHSBInCKdFQGKMY7rsc4rAychxYa8=; h=From:To:Cc:Subject:Date:Reply-To; b=PtpcEpzHcpsxjIXN9ROeCnFmZHr9cn9kMEXM0HfCCaX8sYovAASql2FF+MgqvzXR2 /pAmk1M6QI4L35sFNuY0R/Kge3oS2AxpO3xEN8HqmlIxyMW5fEn9wZHU9seRiAfy2Q vEJ83+yfXzaw56/aCmB7IIeLt6Eh6xN5zWML8BfI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-53040: ocfs2: validate bg_bits during freefrag scan Date: Wed, 24 Jun 2026 17:31:04 +0100 Message-ID: <2026062456-CVE-2026-53040-e3ea@gregkh> X-Mailer: git-send-email 2.54.0 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=5780; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=0Nkm055LUsaqqFmuoRI036pgshNDSbtI5jYj0kQKHKQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDFk2bCyMk2Jf1DAW1UY+69/iOF/QorFMPvbGt/UaZYHib lppVckdsSwMgkwMsmKKLF+28RzdX3FI0cvQ9jTMHFYmkCEMXJwCMBH5mQwL9ihbX3ymEZ/+OU73 weuHnIn9Bx3TGRZMOMJ0+bR3wbvv+7iu6Ya4xc/dOysLAA== 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: ocfs2: validate bg_bits during freefrag scan [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. The Linux kernel CVE team has assigned CVE-2026-53040 to this issue. Affected and fixed versions =========================== Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 5.10.258 with commit bb2906a1065ec28de021bac2ed03f2624edd7d07 Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 5.15.209 with commit 3e167e230d19cd273108bab2e4c61800fc335ae8 Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 6.1.175 with commit 0998674eec138c55e9e349b9cbd9dbc5129a9cc8 Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 6.6.141 with commit bb3c54d1e71578521111f1a1ee7d5f4761a242b8 Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 6.12.91 with commit 05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 6.18.33 with commit 4c2d62ddde8928db12f4608950b67a20e67deab2 Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 7.0.10 with commit e0dcf12665d6dde37facf790803cdad44d5c328c Issue introduced in 3.0 with commit d24a10b9f8ed548981696cd36e2b4f16e6f360b1 and fixed in 7.1 with commit 8f687eeed3da3012152b0f9473f578869de0cd7b 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-2026-53040 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/ocfs2/ioctl.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/bb2906a1065ec28de021bac2ed03f2624edd7d07 https://git.kernel.org/stable/c/3e167e230d19cd273108bab2e4c61800fc335ae8 https://git.kernel.org/stable/c/0998674eec138c55e9e349b9cbd9dbc5129a9cc8 https://git.kernel.org/stable/c/bb3c54d1e71578521111f1a1ee7d5f4761a242b8 https://git.kernel.org/stable/c/05d0cbea41167b6b061c6ba5b70ee5a9a7a24c9e https://git.kernel.org/stable/c/4c2d62ddde8928db12f4608950b67a20e67deab2 https://git.kernel.org/stable/c/e0dcf12665d6dde37facf790803cdad44d5c328c https://git.kernel.org/stable/c/8f687eeed3da3012152b0f9473f578869de0cd7b