From nobody Wed Dec 17 12:21:19 2025 Received: from mail-pl1-f177.google.com (mail-pl1-f177.google.com [209.85.214.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE66F2F8BF1 for ; Tue, 30 Sep 2025 10:25:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.177 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759227961; cv=none; b=saKmOX1R9vI9+Yo5TjbKf28dL8zWiDFxY5lJL6iIiBryNDqkTZ4U3a1clhIzGidHqAOKCT1V3vdMhW4cCx9+aACfcNw+mIglgFF20ewwzxI2pzyFSKO2BpUTk/HSbJmqmysRsK93NWuwAQVGJKf2n1bVFB/+uvU8djnJNDLiBrU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759227961; c=relaxed/simple; bh=rcjBUVQ/qzqGAPyJDjq415/OqkbFTjgHYuWY7Q7758Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=L6JfIX44tag2KIB74wBtpjK2vSQBitmWkeWt4lgRqVP/VSnxPZWq5Dp02JxQJuvCzd5b2tbNM/QjYn6CDXRlLLZXkxEQLwTtegClyjgZnx71l4km6BBfAB90uLa1VgA3AqyGGoaKuuMLQY0sN8FDrZfb364dMwdF2I5EHk7Bj1g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=RZ5aTDp5; arc=none smtp.client-ip=209.85.214.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RZ5aTDp5" Received: by mail-pl1-f177.google.com with SMTP id d9443c01a7336-27eec33b737so60110645ad.1 for ; Tue, 30 Sep 2025 03:25:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759227959; x=1759832759; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Usj+zGMFyo0Na2GYD3pfOZ6hylAz1eRVpObNmN/MNOw=; b=RZ5aTDp5dw30LT4EpHWwAyQov/KSsHT4SKpkjZGBzmoUjBcMVSlCxqpqpnovhhhF4z 35nsxBkY91Z3JaQwZBCKlYUaB3o5NgqjKGDZP3ekkbVujMHbjLvAxFmDxQ1CqDOmH5R/ CUxrk8+4UTmLWZrYTaL7669T1V0fdlOgoBZEJVzLDo8kByJNzhSE7zJrhUnolgGeapWK p2QmbWmRHjrZTzoYeFdZIOHmN0bE6+kYgi7DtFLuEuUjDo6cNfecoF5hkBMRUPRTgO01 O4jUTBm19dVvfMMDJnnB5FgHD1Zj+abIP8vku7h3+VyqxtkQBCzv1OoTTZBQbLrsAicw xXBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759227959; x=1759832759; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Usj+zGMFyo0Na2GYD3pfOZ6hylAz1eRVpObNmN/MNOw=; b=LVcoKric4sF/O5eA3gdnAkE0D/rGUhxujZAJO3U5qCt/x73j2+cTks92shpojbg0Uh J63bXVHOs1Df089pyvG4GcGXKdlMEylE5BQ4dx3Av1GMOjU0swiDqvy+ga6ikSJYNeoe lbOH+VThql1WWVYOYj4P96FOZhUGJbD+vnUJPnfdmLL/zaYNmlv0g0d5ybln2gr0dckf 3evQx4welga3t3hQKotEsHY84NeiwrOelhJI00dUdFz8YN5tk1eHthcefBQdbhKZezXN 0/5gnS15hOBj1HXbEFNTf0lh+UhBLZMU34WlydEwUPzp6eNDaXCXb4VcrTYhCCcO6p27 XbeQ== X-Forwarded-Encrypted: i=1; AJvYcCXPQziqEO1ItifwsW20usVYP968JNAkkCsl1PG0Msfg3ID00obpBQWglrkZ5qizZEclZiOBwCsvRj4fINg=@vger.kernel.org X-Gm-Message-State: AOJu0YzAGbsXZCuG7/k1Q3p3/YHk4DBC8+6QF/Iql4gM2azI/+Gg8vK4 Pf4R5utGX6/CvHLHHxZpI8CdYF6ySXsbcad1Xpf6pt5x4IU78W5J1kds X-Gm-Gg: ASbGncvqbpru4ZZyhPxyF7YQPfOg5kJYzsLVzFKgI+oGEaNQji8PCe+myLmg3F+LAdG FZGlgLz4ypaM0rGW51J8rKyZRf2KvS9//LYq17WcKL7NtmN2XAmtsExt9fuGiEKNk2msE2LteNi qOrPlX3QvA3uHphzMCjqFGFg5wHveVRxmRH4cBlaAk4hVr6HBAa6nmD7t5NTP6t0XVGtbKP6RfC y5ASS1k2KjJQ5EcSm0O+qCcB/9YSfvtQ9+Iy+0RKRSdS4X9zs6C1YnLQh+Tprgef2IYkzxj3vDi Bz7OuvFw+/ek7gAmTe6rhAdkhKFtG6mWEShvFEi+171jRpfVN0+SuvPGxovzkj6wYf5aTpAgZuY 2HMU++H4BRARzs7/EkL4snA++nYymUXBzpr4mVIc6rH9wpPS50kqRblbT2N6Jp0xuPI2VQyvSPf o2SS+z//4YZXfgHORYt01BXr0Gl+s8DfS08t0= X-Google-Smtp-Source: AGHT+IHCbQEqQwID9i1SGsV/gT37SzgPwAgKzlUiVjvvwLB/MstniN5W45shljswpD3SsEPFWYW3IA== X-Received: by 2002:a17:903:46c5:b0:269:87a3:43b8 with SMTP id d9443c01a7336-27ed49c7741mr229629385ad.4.1759227959040; Tue, 30 Sep 2025 03:25:59 -0700 (PDT) Received: from deepanshu-kernel-hacker.. ([2405:201:682f:3094:86eb:e17:c717:ec3]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-27ed69bb502sm153429705ad.118.2025.09.30.03.25.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Sep 2025 03:25:58 -0700 (PDT) From: Deepanshu Kartikey To: tytso@mit.edu, adilger.kernel@dilger.ca Cc: yi.zhang@huaweicloud.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Deepanshu Kartikey , syzbot+038b7bf43423e132b308@syzkaller.appspotmail.com, Zhang Yi Subject: [PATCH v3] ext4: detect invalid INLINE_DATA + EXTENTS flag combination Date: Tue, 30 Sep 2025 15:55:49 +0530 Message-ID: <20250930102549.311578-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.43.0 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" syzbot reported a BUG_ON in ext4_es_cache_extent() when opening a verity file on a corrupted ext4 filesystem mounted without a journal. The issue is that the filesystem has an inode with both the INLINE_DATA and EXTENTS flags set: EXT4-fs error (device loop0): ext4_cache_extents:545: inode #15: comm syz.0.17: corrupted extent tree: lblk 0 < prev 66 Investigation revealed that the inode has both flags set: DEBUG: inode 15 - flag=3D1, i_inline_off=3D164, has_inline=3D1, extents= _flag=3D1 This is an invalid combination since an inode should have either: - INLINE_DATA: data stored directly in the inode - EXTENTS: data stored in extent-mapped blocks Having both flags causes ext4_has_inline_data() to return true, skipping extent tree validation in __ext4_iget(). The unvalidated out-of-order extents then trigger a BUG_ON in ext4_es_cache_extent() due to integer underflow when calculating hole sizes. Fix this by detecting this invalid flag combination early in ext4_iget() and rejecting the corrupted inode. Reported-and-tested-by: syzbot+038b7bf43423e132b308@syzkaller.appspotmail.c= om Closes: https://syzkaller.appspot.com/bug?extid=3D038b7bf43423e132b308 Suggested-by: Zhang Yi Signed-off-by: Deepanshu Kartikey Reviewed-by: Zhang Yi --- Changes in v3: - Fix code alignment and use existing function/line variables per Zhang Yi - Keep check after ret =3D 0 where all inode fields are initialized, as i_inline_off gets set during inode initialization after ext4_set_inode_fl= ags() Changes in v2: - Instead of adding validation in ext4_find_extent(), detect the invalid INLINE_DATA + EXTENTS flag combination in ext4_iget() as suggested by Zhang Yi to avoid redundant checks in the extent lookup path --- fs/ext4/inode.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5b7a15db4953..5c97de5775c7 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5445,6 +5445,15 @@ struct inode *__ext4_iget(struct super_block *sb, un= signed long ino, } =20 ret =3D 0; + /* Detect invalid flag combination - can't have both inline data and exte= nts */ + if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) && + ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + ext4_error_inode(inode, function, line, 0, + "inode has both inline data and extents flags"); + ret =3D -EFSCORRUPTED; + goto bad_inode; + } + if (ei->i_file_acl && !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) { ext4_error_inode(inode, function, line, 0, --=20 2.43.0