linux-kernel - Re: [PATCH] ipv4: fib: avoid NULL dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <92672813-153a-eccb-dbee-4b59bbf657f1@gmail.com>
Date:   Fri, 6 Jul 2018 08:49:14 -0600
From:   David Ahern <dsahern@...il.com>
To:     Mark Rutland <mark.rutland@....com>, linux-kernel@...r.kernel.org
Cc:     Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        "David S . Miller" <davem@...emloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        netdev@...r.kernel.org
Subject: Re: [PATCH] ipv4: fib: avoid NULL dereference

On 7/6/18 8:28 AM, Mark Rutland wrote:
> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
> index 5bc0c89e81e4..8d98c8162554 100644
> --- a/net/ipv4/fib_trie.c
> +++ b/net/ipv4/fib_trie.c
> @@ -497,11 +497,11 @@ static void tnode_free(struct key_vector *tn)
>  	struct callback_head *head = &tn_info(tn)->rcu;
>  
>  	while (head) {
> +		tn = container_of(head, struct tnode, rcu)->kv;
> +
>  		head = head->next;
>  		tnode_free_size += TNODE_SIZE(1ul << tn->bits);
>  		node_free(tn);

you are changing tn before the above 2 calls are made on the tn passed in


> -
> -		tn = container_of(head, struct tnode, rcu)->kv;
>  	}
>  
>  	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
>