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 629F919F11B for ; Wed, 26 Feb 2025 01:57:31 +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=1740535052; cv=none; b=bitQVlXRuMC14yJXZ4+JQdX8wGRYu1w8g06P+/mbuP21iPKRx+SiJZeauZJQSbU0hZYbQ4p6qaSc16WtixTmt4vhNzVHexh9QXRi74QDOjxQ6d7GuyLWmHjMpK1fxX0bdRmxkN5jpZJvWU9b49LCPGgRjGFtD6mNQjdCtMg6eHo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740535052; c=relaxed/simple; bh=fAna0bwH/eUk7obzIlENiGCYxPDMh1XzAhgdNvFMGxI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=LC6KbeSTpxm4cIdxnoeGAEBb5na8SotYCsfCxy+Ny2tBzmps0WbJRubWljlysO78H9/y55eahkGY+zvR9z0iBYhLESsmSU7nUkp3itN5FRR+qSGc1jRi32QDr/BBODns/kxiatTjPVdQEWAOpLDhUakKQhCCCA7JiuWqc/OAC3I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Y6iD8/9D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Y6iD8/9D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB148C4CEE7; Wed, 26 Feb 2025 01:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1740535051; bh=fAna0bwH/eUk7obzIlENiGCYxPDMh1XzAhgdNvFMGxI=; h=From:To:Cc:Subject:Date:Reply-to:From; b=Y6iD8/9DziaBeWX/B9U4fgX6R/8uCwTI5VrkdM2oTdHS2P8/KxfWOJj1KPI/KkeZs y/zyo/h6NeRC6+qS6i/85lXVMYQt585XWymTwKzahQF51raBye/DgfVEYIePiaiszC 2Ap5vP6uAqMHwkyTMCDBYOqxHOPkBC10x+UKQlXk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2021-47656: jffs2: fix use-after-free in jffs2_clear_xattr_subsystem Date: Wed, 26 Feb 2025 02:54:07 +0100 Message-ID: <2025022650-CVE-2021-47656-0abd@gregkh> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=6187; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=fAna0bwH/eUk7obzIlENiGCYxPDMh1XzAhgdNvFMGxI=; b=owGbwMvMwCRo6H6F97bub03G02pJDOn7SvTEXxy1lf7NmtV6VqskPyJF9KrWHg5h3/3eW33WH 5ry6YR/RywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAExEi49hwcSp2pExF6uORS39 U6qcJRL1tVrRmmGePfsaRfPdDtJ+sRsjXpxxZz3k6z8PAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: jffs2: fix use-after-free in jffs2_clear_xattr_subsystem When we mount a jffs2 image, assume that the first few blocks of the image are normal and contain at least one xattr-related inode, but the next block is abnormal. As a result, an error is returned in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then called in jffs2_build_filesystem() and then again in jffs2_do_fill_super(). Finally we can observe the following report: ================================================================== BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac Read of size 8 at addr ffff8881243384e0 by task mount/719 Call Trace: dump_stack+0x115/0x16b jffs2_clear_xattr_subsystem+0x95/0x6ac jffs2_do_fill_super+0x84f/0xc30 jffs2_fill_super+0x2ea/0x4c0 mtd_get_sb+0x254/0x400 mtd_get_sb_by_nr+0x4f/0xd0 get_tree_mtd+0x498/0x840 jffs2_get_tree+0x25/0x30 vfs_get_tree+0x8d/0x2e0 path_mount+0x50f/0x1e50 do_mount+0x107/0x130 __se_sys_mount+0x1c5/0x2f0 __x64_sys_mount+0xc7/0x160 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Allocated by task 719: kasan_save_stack+0x23/0x60 __kasan_kmalloc.constprop.0+0x10b/0x120 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0x1c0/0x870 jffs2_alloc_xattr_ref+0x2f/0xa0 jffs2_scan_medium.cold+0x3713/0x4794 jffs2_do_mount_fs.cold+0xa7/0x2253 jffs2_do_fill_super+0x383/0xc30 jffs2_fill_super+0x2ea/0x4c0 [...] Freed by task 719: kmem_cache_free+0xcc/0x7b0 jffs2_free_xattr_ref+0x78/0x98 jffs2_clear_xattr_subsystem+0xa1/0x6ac jffs2_do_mount_fs.cold+0x5e6/0x2253 jffs2_do_fill_super+0x383/0xc30 jffs2_fill_super+0x2ea/0x4c0 [...] The buggy address belongs to the object at ffff8881243384b8 which belongs to the cache jffs2_xattr_ref of size 48 The buggy address is located 40 bytes inside of 48-byte region [ffff8881243384b8, ffff8881243384e8) [...] ================================================================== The triggering of the BUG is shown in the following stack: ----------------------------------------------------------- jffs2_fill_super jffs2_do_fill_super jffs2_do_mount_fs jffs2_build_filesystem jffs2_scan_medium jffs2_scan_eraseblock <--- ERROR jffs2_clear_xattr_subsystem <--- free jffs2_clear_xattr_subsystem <--- free again ----------------------------------------------------------- An error is returned in jffs2_do_mount_fs(). If the error is returned by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to be executed. If the error is returned by jffs2_build_filesystem(), the jffs2_clear_xattr_subsystem() also does not need to be executed again. So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root' to fix this UAF problem. The Linux kernel CVE team has assigned CVE-2021-47656 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 4.9.311 with commit 9150cb625b46f68d524f4cfd491f1aafc23e10a9 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 4.14.276 with commit 3bd2454162ec6bbb5503233c804fce6e4b6dcec5 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 4.19.238 with commit c3b07c875fa8f906f932976460fd14798596f101 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.4.189 with commit 30bf7244acf32f19cb722c39f7bc1c2a9f300422 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.10.110 with commit 7bb7428dd73991bf4b3a7a61b493ca50046c2b13 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.15.33 with commit 7a75740206af5f17e9f3efa384211cba70213da1 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.16.19 with commit 22327bd7988f21de3a53c1373f3b81542bfe1f44 Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.17.2 with commit 8c0f024f29e055840a5a89fe23b96ae3f921afed Issue introduced in 2.6.18 with commit aa98d7cf59b5b0764d3502662053489585faf2fe and fixed in 5.18 with commit 4c7c44ee1650677fbe89d86edbad9497b7679b5c 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-2021-47656 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/jffs2/fs.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/9150cb625b46f68d524f4cfd491f1aafc23e10a9 https://git.kernel.org/stable/c/3bd2454162ec6bbb5503233c804fce6e4b6dcec5 https://git.kernel.org/stable/c/c3b07c875fa8f906f932976460fd14798596f101 https://git.kernel.org/stable/c/30bf7244acf32f19cb722c39f7bc1c2a9f300422 https://git.kernel.org/stable/c/7bb7428dd73991bf4b3a7a61b493ca50046c2b13 https://git.kernel.org/stable/c/7a75740206af5f17e9f3efa384211cba70213da1 https://git.kernel.org/stable/c/22327bd7988f21de3a53c1373f3b81542bfe1f44 https://git.kernel.org/stable/c/8c0f024f29e055840a5a89fe23b96ae3f921afed https://git.kernel.org/stable/c/4c7c44ee1650677fbe89d86edbad9497b7679b5c