linux-kernel - Re: [V9fs-developer] [PATCH] version pointer uninitialized

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Message-ID: <02d636a1-858a-45a5-d28c-9f7380d27ab3@gmail.com>
Date:   Thu, 12 Jul 2018 18:44:17 +0200
From:   Tomas Bortoli <tomasbortoli@...il.com>
To:     jiangyiwen <jiangyiwen@...wei.com>, ericvh@...il.com,
        rminnich@...dia.gov, lucho@...kov.net
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller@...glegroups.com, v9fs-developer@...ts.sourceforge.net,
        davem@...emloft.net, Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [V9fs-developer] [PATCH] version pointer uninitialized

On 07/11/2018 03:26 AM, jiangyiwen wrote:
> On 2018/7/10 6:29, Tomas Bortoli wrote:
>> The p9_client_version() does not initialize the version
>> pointer. If the call to p9pdu_readf() returns an error and version has not
>> been allocated in p9pdu_readf(), then the program will jump to the "error"
>> label and will try to free the version pointer. If version is not
>> initialized, free() will be called with uninitialized, garbage data and
>> will provoke a crash.
>>
>> Signed-off-by: Tomas Bortoli <tomasbortoli@...il.com>
> Reviewed-by: Yiwen Jiang <jiangyiwen@...wei.com>
>
>> Reported-by: syzbot+65c6b72f284a39d416b4@...kaller.appspotmail.com
>> ---
>>  net/9p/client.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/9p/client.c b/net/9p/client.c
>> index 18c5271910dc..40f7c47f2f74 100644
>> --- a/net/9p/client.c
>> +++ b/net/9p/client.c
>> @@ -957,7 +957,7 @@ static int p9_client_version(struct p9_client *c)
>>  {
>>  	int err = 0;
>>  	struct p9_req_t *req;
>> -	char *version;
>> +	char *version = NULL;
>>  	int msize;
>>  
>>  	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
>>
>

+ Cc: Andrew Morton <akpm@...ux-foundation.org>

This goes with the other patch: [V9fs-developer] [PATCH]
p9_parse_header() validate PDU length

Tomas