[Ocfs2-devel] [PATCH] ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()

[Li Tuo]

Thanks for your feedback. We will prepare a V2 patch according to your advice.

Best wishes,
Tuo Li

On 2021/7/31 21:57, Joseph Qi wrote:
> Thanks for the efforts.
> For the issue you mentioned, I'd like just initialized
> oinfo->dqi_gqinode as NULL before calling ocfs2_global_read_info().
> But it seems still have other issues here such as dqi_gqlock.
> We need take care all those initialized in ocfs2_global_read_info()
> carefully.
>
> Thanks,
> Joseph
>
> On 7/31/21 3:56 PM, Tuo Li wrote:
>> A memory block is allocated through kmalloc(), and its return value is
>> assigned to the pointer oinfo. If the return value of
>> ocfs2_global_read_info() at line 709 is less than zero,
>> oinfo->dqi_gqinode may be not initialized. However, it is accessed at
>> line 775:
>>    iput(oinfo->dqi_gqinode);
>>
>> To fix this possible uninitialized-variable access, replace kmalloc()
>> with kzalloc() when allocating memory for oinfo.
>>
>> Reported-by: TOTE Robot <oslab at tsinghua.edu.cn>
>> Signed-off-by: Tuo Li <islituo at gmail.com>
>> ---
>>   fs/ocfs2/quota_local.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
>> index b1a8b046f4c2..4c1219e08b49 100644
>> --- a/fs/ocfs2/quota_local.c
>> +++ b/fs/ocfs2/quota_local.c
>> @@ -693,7 +693,7 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
>>   
>>   	info->dqi_max_spc_limit = 0x7fffffffffffffffLL;
>>   	info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
>> -	oinfo = kmalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
>> +	oinfo = kzalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
>>   	if (!oinfo) {
>>   		mlog(ML_ERROR, "failed to allocate memory for ocfs2 quota"
>>   			       " info.");
>>

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