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

[Jon M. <jm...@re...>]

Acked-by: Jon Maloy <jm...@re...>

On 5/26/22 07:02, 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.
>
> Reported-by: syz...@sy...
> Signed-off-by: Hoang Le <hoa...@de...>
> ---
>   net/tipc/bearer.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
> index 6d39ca05f249..0fd7554c7cde 100644
> --- a/net/tipc/bearer.c
> +++ b/net/tipc/bearer.c
> @@ -258,10 +258,10 @@ static int tipc_enable_bearer(struct net *net, const char *name,
>   	char *errstr = "";
>   	u32 i;
>   
> -	if (!bearer_name_validate(name, &b_names)) {
> -		errstr = "illegal name";
> +	if (strlen(name) > TIPC_MAX_BEARER_NAME ||
> +	    !bearer_name_validate(name, &b_names)) {
>   		NL_SET_ERR_MSG(extack, "Illegal name");
> -		goto rejected;
> +		return res;
>   	}
>   
>   	if (prio > TIPC_MAX_LINK_PRI && prio != TIPC_MEDIA_LINK_PRI) {