From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794313898; b=wB7pzVTcIaqYT2lfn3GWWo1xOVAtCNU/bsVQifnlazRp2m2+67UMNlXtyQNyFb/5Oyc3 OTYk/6+CPSNsW9r/DovCE0t6Lg2l5XHiaNdVSrrhg8AMPW57OuY3EsWWnLnr1GiKNg2DA HwrpB2raHGlVVIdmxxB/scl5Y8XhGdxsCASEwoqn7YzCUK10cd15y/CqyltPTVVmWXNwG yYT69kH1n0jwx/GWq3/Xt55IJG/c+phRKWCUjOj1/Rae6quyg8nSvo/JJyIKoIG9EL5x9 ZrIVTUsaqA/Igid/kl4CzksxJMyQJmN9N6h4t32bctRwuULrLKT3mptQRVgnvXvkk7g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794313898; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=0Px9meDwVxdSFJRp1wavOES8p66Y34pNoVX5MGwrgOY=; b=5c7gPs5ewtbNT1MsiIsSOBZ4LjegV7s+P6gQHhU4lNj6r3LTqxMNQN4rHb+EWzKB0bWR tTu+5c2SIX3sQt22QL3klSCmBGvQNSbBx7SeBp7TotiniAZT6S6iWA5UtTrou9tV+t0Hy JOuH7jxFt0QZX3slP6fNkgTbqwSRYEtBGtiOmNfArqzxpLEEWZm83TPO6zBGfx1Sd7oYx leVrNSBWD2yyo90bmaY+4GHRJLqioQoRaAzvsryVB8Ap31xONQ761n63AqVI1jMG9JIio VndTezma1cxldWahGFks+Qy+ubTRLZd61iTaNo22M0noNU/gnqcAbOsjc8KPgj4AjnQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=R6uT6ZsC; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19A69606A321 for ; Tue, 10 Nov 2026 12:31:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=R6uT6ZsC Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69B521F008A1; Tue, 10 Nov 2026 12:31:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794313897; bh=0Px9meDwVxdSFJRp1wavOES8p66Y34pNoVX5MGwrgOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=R6uT6ZsC/nISC3iX7XygbjPnFQMNvQZfgLS4EjUFxKzGG11ARqs0XENjKO/FP2XwG fLOM0y20xg14dJLPahwF7VHJlvIQ1YH+8bf/9PkCgKsUIkMgsEe2oOtgkSvODOgDPc azgLia8jZpDNhvbImCm7Ycxxg5c6E7+V64hmd9IPAK6KsrbjedBliejnXh5Ou/2f7O g8CNcYTSC1yD1sjltYPbgMIhfhsXXYLuxrFYVQfaj75dH5eI1p3jXE8WLqzIsIZ8q7 wR9vy384kUFAjWb5xIg8vWXMrn8pOsxOXgb/G9S4FyeUhr0Us1WGU3mjhWZZkrP1pR TJFEy1n7z0Iew== From: Sasha Levin To: stable@vger.kernel.org Cc: Joseph Qi , Andrew Morton , Changwei Ge , Heming Zhao , Joel Becker , Jun Piao , Junxiao Bi , Mark Fasheh , Sasha Levin Subject: [PATCH 6.6.y] ocfs2: restrict OCFS2_INVALID_SLOT suballoc slot to system inodes Date: Tue, 10 Nov 2026 07:31:35 -0500 Message-ID: <20261110123115.1278382-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107053226-failed-6.6-25bf9e549360@kernel.org> References: <20261107053226-failed-6.6-25bf9e549360@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Joseph Qi [ Upstream commit 25bf9e549360b656a6763232e0e9e58a00c3aff7 ] Patch series "ocfs2: validate suballoc slot and bit of metadata blocks", v3. The ocfs2 metadata validators trust the on-disk suballoc slot and bit without checking them against the slot range of the mounted filesystem and the capacity of the block group bitmap. A corrupted image can carry OCFS2_INVALID_SLOT or another out-of-range slot, or a suballoc bit beyond the bitmap, and once the corresponding inode, extent block, xattr block, dir index root or refcount block gets freed, the bad value goes straight into ocfs2_get_system_file_inode() or _ocfs2_free_suballoc_bits() and hits a BUG_ON() or runs off the end of local_system_inodes[]. This series rejects such values at read time, in the existing validators, so corrupted objects fail with -EROFS (and a read-only remount) instead of crashing: patch 1 restricts OCFS2_INVALID_SLOT dinodes to system inodes, completing fe7a283b3916 ("ocfs2: add suballoc slot check in ocfs2_validate_inode_block()"), and turns the "system file state is ambiguous" BUG_ON() in ocfs2_read_locked_inode() into an ocfs2_error(); patch 2 rejects oversized dinode suballoc bits; patch 3 validates the suballoc slot and bit of xattr and dir index blocks; patch 4 validates the suballoc slot and bit of extent and refcount blocks. The checks only enforce what the kernel and mkfs.ocfs2 already write: a valid slot from meta_ac->ac_alloc_slot and a bit within the block group bitmap, with system inodes carrying OCFS2_INVALID_SLOT plus OCFS2_SYSTEM_FL and extent blocks using slot 0. Nothing changes for healthy filesystems. Each new check was exercised under QEMU by corrupting the field in question with an out-of-range value; with the series applied the access fails with -EROFS and the filesystem remounts read-only instead of hitting the BUG_ON(). This patch (of 4): ocfs2_validate_inode_block() currently permits i_suballoc_slot to be OCFS2_INVALID_SLOT for any dinode. Only system inodes created by mkfs.ocfs2 are allocated from the global allocator and thus legitimately carry this value; regular inodes are always allocated from a per-slot suballocator and hence must have a valid slot. If a corrupted regular inode with OCFS2_INVALID_SLOT is accepted, ocfs2_remove_inode() will pass the slot to ocfs2_get_system_file_inode() and get_local_system_inode() will hit BUG_ON(slot == OCFS2_INVALID_SLOT) when the inode is deleted. This can be triggered by an unprivileged user unlinking such a corrupted file. Reject OCFS2_INVALID_SLOT for non-system dinodes during validation, while still accepting it for system inodes. Note that a crafted dinode carrying OCFS2_SYSTEM_FL passes the check above, yet a plain lookup of it still used to BUG() in ocfs2_read_locked_inode() ("system file state is ambiguous"). Since i_flags comes from disk, handle that mismatch with ocfs2_error() instead of BUG_ON() as well. Link: https://lore.kernel.org/20260901125221.1634686-1-joseph.qi@linux.alibaba.com Link: https://lore.kernel.org/20260901125221.1634686-2-joseph.qi@linux.alibaba.com Fixes: fe7a283b3916 ("ocfs2: add suballoc slot check in ocfs2_validate_inode_block()") Signed-off-by: Joseph Qi Signed-off-by: Andrew Morton Cc: Changwei Ge Cc: Heming Zhao Cc: Joel Becker Cc: Jun Piao Cc: Junxiao Bi Cc: Mark Fasheh Cc: [ sashal: adjusted context around the suballoc slot check in ocfs2_validate_inode_block() ] Signed-off-by: Sasha Levin --- fs/ocfs2/inode.c | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index 01e33782f4f6e..213cc1ebc14b8 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -573,14 +573,18 @@ static int ocfs2_read_locked_inode(struct inode *inode, fe = (struct ocfs2_dinode *) bh->b_data; /* - * This is a code bug. Right now the caller needs to - * understand whether it is asking for a system file inode or - * not so the proper lock names can be built. + * The caller must know whether it is asking for a system file inode + * or not so the proper lock names can be built. Since i_flags comes + * from disk, a mismatch is filesystem corruption instead of a code + * bug, so handle it with ocfs2_error() rather than BUG_ON(). */ - mlog_bug_on_msg(!!(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL)) != - !!(args->fi_flags & OCFS2_FI_FLAG_SYSFILE), - "Inode %llu: system file state is ambiguous\n", - (unsigned long long)args->fi_blkno); + if (!!(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL)) != + !!(args->fi_flags & OCFS2_FI_FLAG_SYSFILE)) { + status = ocfs2_error(osb->sb, + "Inode %llu: system file state is ambiguous\n", + (unsigned long long)args->fi_blkno); + goto bail; + } if (S_ISCHR(le16_to_cpu(fe->i_mode)) || S_ISBLK(le16_to_cpu(fe->i_mode))) @@ -1597,8 +1601,23 @@ int ocfs2_validate_inode_block(struct super_block *sb, } } - if (le16_to_cpu(di->i_suballoc_slot) != (u16)OCFS2_INVALID_SLOT && - (u32)le16_to_cpu(di->i_suballoc_slot) > OCFS2_SB(sb)->max_slots - 1) { + /* + * Only system inodes created by mkfs.ocfs2 are allocated from the + * global allocator and thus legitimately carry OCFS2_INVALID_SLOT. + * Regular inodes are always allocated from a per-slot suballocator. + * If a regular inode with OCFS2_INVALID_SLOT was accepted here, + * deleting it would pass the slot to get_local_system_inode() via + * ocfs2_remove_inode() and trigger BUG_ON(slot == OCFS2_INVALID_SLOT). + */ + if (le16_to_cpu(di->i_suballoc_slot) == (u16)OCFS2_INVALID_SLOT) { + if (!(le32_to_cpu(di->i_flags) & OCFS2_SYSTEM_FL)) { + rc = ocfs2_error(sb, + "Invalid dinode %llu: suballoc slot %u for non-system inode\n", + (unsigned long long)bh->b_blocknr, + le16_to_cpu(di->i_suballoc_slot)); + goto bail; + } + } else if ((u32)le16_to_cpu(di->i_suballoc_slot) > OCFS2_SB(sb)->max_slots - 1) { rc = ocfs2_error(sb, "Invalid dinode %llu: suballoc slot %u\n", (unsigned long long)bh->b_blocknr, le16_to_cpu(di->i_suballoc_slot)); -- 2.53.0