From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 B270618028 for ; Tue, 16 Jul 2024 02:12:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721095928; cv=none; b=btUik9gXrOs/4sM3NGbxPEj/uf8Zyatq3Wq6K8AhCosCofnIo8Df5mXhy3TyPX0WuW5esfD8p4SJbPGX6MqPgnk2RG7D0RFcUo0cKEc0MkJrIcp7E5+yJzqGg8YOZb3jcwiyQUgRBqxbj08j4cFxbiywJWCOVNsezcPUQPbsr4Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721095928; c=relaxed/simple; bh=2gAvbUggJLdIYoMTeoRLq2CnFZUmuS/WFxayjJM8DiI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=fEXpaXnMOW0NRiWpXMF1vDmwxfSV5TzohGce6wYTBE/EcBw46ie6/N2aeFc6fB1XBn0TRvEDjwrt+lYffAry19uWcxZIuZz5sHCnixZcP0P2en9dKV+vtoYDAQ4CuPMEunnh7jhxIwZmNrIx1lJrMY4/Ed1gBinJvyDqGPrBUYM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4WNMyD6g9Rz4f3jXV for ; Tue, 16 Jul 2024 10:11:48 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id DC0291A058E for ; Tue, 16 Jul 2024 10:12:00 +0800 (CST) Received: from [10.174.177.174] (unknown [10.174.177.174]) by APP4 (Coremail) with SMTP id gCh0CgA3Gznr1pVmVPgFAQ--.376S3; Tue, 16 Jul 2024 10:11:59 +0800 (CST) Message-ID: Date: Tue, 16 Jul 2024 10:11:55 +0800 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6.6/6.9 v2 2/2] ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists() To: gregkh@linuxfoundation.org Cc: sashal@kernel.org, yangerkun@huawei.com, Jan Kara , Ojaswin Mujoo , Theodore Ts'o , libaokun@huaweicloud.com, stable@vger.kernel.org References: <20240619121952.3508695-1-libaokun@huaweicloud.com> <20240619121952.3508695-2-libaokun@huaweicloud.com> Content-Language: en-US From: Baokun Li In-Reply-To: <20240619121952.3508695-2-libaokun@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID:gCh0CgA3Gznr1pVmVPgFAQ--.376S3 X-Coremail-Antispam: 1UD129KBjvJXoWxKw1fGw15Zw17XryxXFyfXrb_yoWxWr4fpa nIyFyxGr1FgryUWr4kC3Z0g34Fgw4xC3WUXryfXw18ZasrJF1Skr9rtF1YvF1kKrWkZF1f XFW2qFnrKrsrWa7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkv14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7CjxVAaw2AFwI0_JF0_ Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxV WUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI 7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r 1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI 42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUBVbkUUUUU= X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/1tbiAgAGBWaU3hQ7-AAAs+ On 2024/6/19 20:19, libaokun@huaweicloud.com wrote: > From: Baokun Li > > [ Upstream commit 13df4d44a3aaabe61cd01d277b6ee23ead2a5206 ] > > We can trigger a slab-out-of-bounds with the following commands: > > mkfs.ext4 -F /dev/$disk 10G > mount /dev/$disk /tmp/test > echo 2147483647 > /sys/fs/ext4/$disk/mb_group_prealloc > echo test > /tmp/test/file && sync > > ================================================================== > BUG: KASAN: slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4] > Read of size 8 at addr ffff888121b9d0f0 by task kworker/u2:0/11 > CPU: 0 PID: 11 Comm: kworker/u2:0 Tainted: GL 6.7.0-next-20240118 #521 > Call Trace: > dump_stack_lvl+0x2c/0x50 > kasan_report+0xb6/0xf0 > ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4] > ext4_mb_regular_allocator+0x19e9/0x2370 [ext4] > ext4_mb_new_blocks+0x88a/0x1370 [ext4] > ext4_ext_map_blocks+0x14f7/0x2390 [ext4] > ext4_map_blocks+0x569/0xea0 [ext4] > ext4_do_writepages+0x10f6/0x1bc0 [ext4] > [...] > ================================================================== > > The flow of issue triggering is as follows: > > // Set s_mb_group_prealloc to 2147483647 via sysfs > ext4_mb_new_blocks > ext4_mb_normalize_request > ext4_mb_normalize_group_request > ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc > ext4_mb_regular_allocator > ext4_mb_choose_next_group > ext4_mb_choose_next_group_best_avail > mb_avg_fragment_size_order > order = fls(len) - 2 = 29 > ext4_mb_find_good_group_avg_frag_lists > frag_list = &sbi->s_mb_avg_fragment_size[order] > if (list_empty(frag_list)) // Trigger SOOB! > > At 4k block size, the length of the s_mb_avg_fragment_size list is 14, > but an oversized s_mb_group_prealloc is set, causing slab-out-of-bounds > to be triggered by an attempt to access an element at index 29. > > Add a new attr_id attr_clusters_in_group with values in the range > [0, sbi->s_clusters_per_group] and declare mb_group_prealloc as > that type to fix the issue. In addition avoid returning an order > from mb_avg_fragment_size_order() greater than MB_NUM_ORDERS(sb) > and reduce some useless loops. > > Fixes: 7e170922f06b ("ext4: Add allocation criteria 1.5 (CR1_5)") > CC: stable@vger.kernel.org > Signed-off-by: Baokun Li > Reviewed-by: Jan Kara > Reviewed-by: Ojaswin Mujoo > Link: https://lore.kernel.org/r/20240319113325.3110393-5-libaokun1@huawei.com > Signed-off-by: Theodore Ts'o > Signed-off-by: Sasha Levin > Signed-off-by: Baokun Li > --- > fs/ext4/mballoc.c | 4 ++++ > fs/ext4/sysfs.c | 15 ++++++++++++++- > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 714f83632e3f..66b5a68b0254 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -831,6 +831,8 @@ static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len) > return 0; > if (order == MB_NUM_ORDERS(sb)) > order--; > + if (WARN_ON_ONCE(order > MB_NUM_ORDERS(sb))) > + order = MB_NUM_ORDERS(sb) - 1; > return order; > } > > @@ -1008,6 +1010,8 @@ static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context > * goal length. > */ > order = fls(ac->ac_g_ex.fe_len) - 1; > + if (WARN_ON_ONCE(order - 1 > MB_NUM_ORDERS(ac->ac_sb))) > + order = MB_NUM_ORDERS(ac->ac_sb); > min_order = order - sbi->s_mb_best_avail_max_trim_order; > if (min_order < 0) > min_order = 0; > diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c > index ca820620b974..d65dccb44ed5 100644 > --- a/fs/ext4/sysfs.c > +++ b/fs/ext4/sysfs.c > @@ -29,6 +29,7 @@ typedef enum { > attr_trigger_test_error, > attr_first_error_time, > attr_last_error_time, > + attr_clusters_in_group, > attr_feature, > attr_pointer_ui, > attr_pointer_ul, > @@ -207,13 +208,14 @@ EXT4_ATTR_FUNC(sra_exceeded_retry_limit, 0444); > > EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead, > ext4_sb_info, s_inode_readahead_blks); > +EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group, > + ext4_sb_info, s_mb_group_prealloc); > EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); > EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); > EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); > EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan); > EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); > EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request); > -EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc); > EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups); > EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb); > EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error); > @@ -392,6 +394,7 @@ static ssize_t ext4_attr_show(struct kobject *kobj, > (unsigned long long) > percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit)); > case attr_inode_readahead: > + case attr_clusters_in_group: > case attr_pointer_ui: > if (!ptr) > return 0; > @@ -469,6 +472,16 @@ static ssize_t ext4_attr_store(struct kobject *kobj, > else > *((unsigned int *) ptr) = t; > return len; > + case attr_clusters_in_group: Hi Greg, > + if (!ptr) > + return 0; I've found that the commit that eventually gets merged in doesn't have this judgment. 6.6: 677ff4589f15 ("ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists()") 6.9: b829687ae122 ("ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists()") This may result in a null pointer dereference. History: https://lore.kernel.org/all/0d620010-c6b4-4f80-a835-451813f957e3@huawei.com/ https://lore.kernel.org/all/20240619121952.3508695-2-libaokun@huaweicloud.com/ https://lore.kernel.org/all/20240625085542.189183696@linuxfoundation.org/ Regards, Baokun > + ret = kstrtouint(skip_spaces(buf), 0, &t); > + if (ret) > + return ret; > + if (t > sbi->s_clusters_per_group) > + return -EINVAL; > + *((unsigned int *) ptr) = t; > + return len; > case attr_pointer_ul: > if (!ptr) > return 0;