From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (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 4699810EA for ; Sat, 28 Oct 2023 06:49:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4SHVPH3j5QzpWRL; Sat, 28 Oct 2023 14:44:03 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Sat, 28 Oct 2023 14:48:58 +0800 From: Baokun Li To: CC: , , , , , , , Subject: [PATCH 5.4 3/3] ext4: avoid overlapping preallocations due to overflow Date: Sat, 28 Oct 2023 14:53:31 +0800 Message-ID: <20231028065331.948339-3-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20231028065331.948339-1-libaokun1@huawei.com> References: <20231028065331.948339-1-libaokun1@huawei.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpeml500021.china.huawei.com (7.185.36.21) X-CFilter-Loop: Reflected commit bedc5d34632c21b5adb8ca7143d4c1f794507e4c upstream. Let's say we want to allocate 2 blocks starting from 4294966386, after predicting the file size, start is aligned to 4294965248, len is changed to 2048, then end = start + size = 0x100000000. Since end is of type ext4_lblk_t, i.e. uint, end is truncated to 0. This causes (pa->pa_lstart >= end) to always hold when checking if the current extent to be allocated crosses already preallocated blocks, so the resulting ac_g_ex may cross already preallocated blocks. Hence we convert the end type to loff_t and use pa_logical_end() to avoid overflow. Signed-off-by: Baokun Li Reviewed-by: Ritesh Harjani (IBM) Link: https://lore.kernel.org/r/20230724121059.11834-4-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Conflicts: fs/ext4/mballoc.c Signed-off-by: Baokun Li --- fs/ext4/mballoc.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 901302735f1c..a0ec645bd7ed 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3094,8 +3094,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); struct ext4_super_block *es = sbi->s_es; int bsbits, max; - ext4_lblk_t end; - loff_t size, start_off; + loff_t size, start_off, end; loff_t orig_size __maybe_unused; ext4_lblk_t start; struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); @@ -3203,7 +3202,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, /* check we don't cross already preallocated blocks */ rcu_read_lock(); list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) { - ext4_lblk_t pa_end; + loff_t pa_end; if (pa->pa_deleted) continue; @@ -3213,8 +3212,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, continue; } - pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb), - pa->pa_len); + pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa); /* PA must not overlap original request */ BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end || @@ -3243,12 +3241,11 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, /* XXX: extra loop to check we really don't overlap preallocations */ rcu_read_lock(); list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) { - ext4_lblk_t pa_end; + loff_t pa_end; spin_lock(&pa->pa_lock); if (pa->pa_deleted == 0) { - pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb), - pa->pa_len); + pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa); BUG_ON(!(start >= pa_end || end <= pa->pa_lstart)); } spin_unlock(&pa->pa_lock); -- 2.31.1