• Florian Westphal's avatar
    netfilter: avoid erronous array bounds warning · 421c119f
    Florian Westphal authored
    Unfortunately some versions of gcc emit following warning:
      $ make net/xfrm/xfrm_output.o
      linux/compiler.h:252:20: warning: array subscript is above array bounds [-Warray-bounds]
      hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
                                ^~~~~~~~~~~~~~~~~~~~~
    xfrm_output_resume passes skb_dst(skb)->ops->family as its 'pf' arg so compiler
    can't know that we'll never access hooks_arp[].
    (NFPROTO_IPV4 or NFPROTO_IPV6 are only possible cases).
    
    Avoid this by adding an explicit WARN_ON_ONCE() check.
    
    This patch has no effect if the family is a compile-time constant as gcc
    will remove the switch() construct entirely.
    Reported-by: default avatarDavid Ahern <dsahern@gmail.com>
    Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
    Reviewed-by: default avatarDavid Ahern <dsahern@gmail.com>
    Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
    421c119f
netfilter.h 13.2 KB