Re: [PATCH] fix mem-leak in netfilter

[Grant Coady]

On Sun, 7 May 2006 11:36:40 +0200, Willy Tarreau <willy@xxxxxxxxx> wrote:

>On Sun, May 07, 2006 at 04:26:10AM +0200, Jesper Juhl wrote:
>> The Coverity checker spotted that we may leak 'hold' in 
>> net/ipv4/netfilter/ipt_recent.c::checkentry() when the following
>> is true : 
>>   if (!curr_table->status_proc) {
>>     ...
>>     if(!curr_table) {
>>     ...
>>       return 0;  <-- here we leak.
>> Simply moving an existing vfree(hold); up a bit avoids the possible leak.
>> 
>> 
>> (please keep me on CC when replying since I'm not subscribed 
>>  to netfilter-devel)
>> 
>> 
>> Signed-off-by: Jesper Juhl <jesper.juhl@xxxxxxxxx>
>> ---
>> 
>>  net/ipv4/netfilter/ipt_recent.c |    2 +-
>>  1 files changed, 1 insertion(+), 1 deletion(-)
>> 
>> --- linux-2.6.17-rc3-git12-orig/net/ipv4/netfilter/ipt_recent.c	2006-05-07 03:25:38.000000000 +0200
>> +++ linux-2.6.17-rc3-git12/net/ipv4/netfilter/ipt_recent.c	2006-05-07 04:16:26.000000000 +0200
>> @@ -821,6 +821,7 @@ checkentry(const char *tablename,
>>  	/* Create our proc 'status' entry. */
>>  	curr_table->status_proc = create_proc_entry(curr_table->name, ip_list_perms, proc_net_ipt_recent);
>>  	if (!curr_table->status_proc) {
>> +		vfree(hold);
>>  		printk(KERN_INFO RECENT_NAME ": checkentry: unable to allocate for /proc entry.\n");
>>  		/* Destroy the created table */
>>  		spin_lock_bh(&recent_lock);
>> @@ -845,7 +846,6 @@ checkentry(const char *tablename,
>>  		spin_unlock_bh(&recent_lock);
>>  		vfree(curr_table->time_info);
>>  		vfree(curr_table->hash_table);
>> -		vfree(hold);
>>  		vfree(curr_table->table);
>>  		vfree(curr_table);
>>  		return 0;
>
>Seems valid for 2.4.32 too. I'm queuing it up for Marcelo.

When CONFIG_PROC_FS is not set the function looks like it may exit 
without doing the vfree()s for stuff allocated above the #ifdef 
CONFIG_PROC_FS.  

I wonder if the larger view of the function is also correct?  The 
coding style is difficult to work with as my terminal only goes to 
156 characters wide ;)  

Grant.
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