[Ocfs2-tools-devel] [PATCH] libocfs2: fulfill lookup with zero firstly in ocfs2_find_entry_dx

[Joseph Qi]

Applied. Thanks.

On 17/11/17 09:30, alex chen wrote:
> Hi Changwei,
> 
> It looks good for me.
> 
> Thanks,
> Alex
> 
> On 2017/11/16 14:58, Changwei Ge wrote:
>> If ocfs2_find_entry_dx() fails with allocating memory or reading dx 
>> root, code path will jump to _out_ and try to release resources managed 
>> by lookup variable. However it is never initialized thus cause a crash 
>> issue.
>>
>> Backtrace follows:
>>
>> __GI___libc_free (mem=0x17) at malloc.c:2929
>> 0x0000000000417e2c in ?? () at memory.c:59
>> 0x00007ffd2c39e6f0 in ?? ()
>> 0x000000000042a924 in release_lookup_res (res=0x17) at
>> dir_indexed.c:1502
>> 0x0000000000417d1f in ocfs2_find_entry_dx (ls=0x7ffd2c39e730,
>> fs=0x2238300, di=<optimized out>,
>> buf=<optimized out>) at lookup.c:76
>> ocfs2_lookup (fs=0x2238300, dir=514, name=<optimized out>,
>> namelen=<optimized out>, buf=0x0,
>> inode=<optimized out>) at lookup.c:128
>> 0x00000000004071ee in do_open (args=<optimized out>) at commands.c:746
>> 0x000000000040775f in do_command (cmd=<optimized out>) at commands.c:346
>> 0x0000000000403684 in main (argc=35877120, argv=0x7ffd2c39eb18) at
>> main.c:487
>>
>> Signed-off-by: Kai Li <li.kai4 at h3c.com>
>> Signed-off-by: Changwei Ge <ge.changwei at h3c.com>
> 
> Reviewed-by: Alex Chen <alex.chen at huawei.com>
> 
>> ---
>>   libocfs2/lookup.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/libocfs2/lookup.c b/libocfs2/lookup.c
>> index c217c12d0fea..a8d0f3c7fed3 100644
>> --- a/libocfs2/lookup.c
>> +++ b/libocfs2/lookup.c
>> @@ -73,6 +73,8 @@ static errcode_t ocfs2_find_entry_dx(ocfs2_filesys *fs,
>>   	struct ocfs2_dir_lookup_result lookup;
>>   	errcode_t ret;
>>
>> +	memset(&lookup, 0, sizeof(struct ocfs2_dir_lookup_result));
>> +
>>   	ret = ocfs2_malloc_block(fs->fs_io, &dx_root_buf);
>>   	if (ret)
>>   		goto out;
>> @@ -81,7 +83,6 @@ static errcode_t ocfs2_find_entry_dx(ocfs2_filesys *fs,
>>   		goto out;
>>   	dx_root = (struct ocfs2_dx_root_block *)dx_root_buf;
>>
>> -	memset(&lookup, 0, sizeof(struct ocfs2_dir_lookup_result));
>>   	ocfs2_dx_dir_name_hash(fs, ls->name,
>>   			ls->len, &lookup.dl_hinfo);
>>
>