Re: [net v3] tipc: check attribute length for bearer name

[Leon Romanovsky <leon@kernel.org>]

On Thu, Jun 02, 2022 at 11:57:57AM +0700, Hoang Le wrote:
> syzbot reported uninit-value:
> =====================================================
> BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:644 [inline]
> BUG: KMSAN: uninit-value in string+0x4f9/0x6f0 lib/vsprintf.c:725
>  string_nocheck lib/vsprintf.c:644 [inline]
>  string+0x4f9/0x6f0 lib/vsprintf.c:725
>  vsnprintf+0x2222/0x3650 lib/vsprintf.c:2806
>  vprintk_store+0x537/0x2150 kernel/printk/printk.c:2158
>  vprintk_emit+0x28b/0xab0 kernel/printk/printk.c:2256
>  vprintk_default+0x86/0xa0 kernel/printk/printk.c:2283
>  vprintk+0x15f/0x180 kernel/printk/printk_safe.c:50
>  _printk+0x18d/0x1cf kernel/printk/printk.c:2293
>  tipc_enable_bearer net/tipc/bearer.c:371 [inline]
>  __tipc_nl_bearer_enable+0x2022/0x22a0 net/tipc/bearer.c:1033
>  tipc_nl_bearer_enable+0x6c/0xb0 net/tipc/bearer.c:1042
>  genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
> 
> - Do sanity check the attribute length for TIPC_NLA_BEARER_NAME.
> - Do not use 'illegal name' in printing message.
> 
> v3: add Fixes tag in commit message.
> v2: remove unnecessary sanity check as Jakub's comment.

Same comment as for v2, please put changelog after --- trailer.

Thanks

> 
> Reported-by: syzbot+e820fdc8ce362f2dea51@syzkaller.appspotmail.com
> Fixes: cb30a63384bc ("tipc: refactor function tipc_enable_bearer()")
> Acked-by: Jon Maloy <jmaloy@redhat.com>
> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
> ---
>  net/tipc/bearer.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
> index 6d39ca05f249..932c87b98eca 100644
> --- a/net/tipc/bearer.c
> +++ b/net/tipc/bearer.c
> @@ -259,9 +259,8 @@ static int tipc_enable_bearer(struct net *net, const char *name,
>  	u32 i;
>  
>  	if (!bearer_name_validate(name, &b_names)) {
> -		errstr = "illegal name";
>  		NL_SET_ERR_MSG(extack, "Illegal name");
> -		goto rejected;
> +		return res;
>  	}
>  
>  	if (prio > TIPC_MAX_LINK_PRI && prio != TIPC_MEDIA_LINK_PRI) {
> -- 
> 2.30.2
>