Re: [PATCH] netfilter: nf_conntrack_sctp: fix build warning

[Patrick McHardy <kaber@trash.net>]

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Wu Fengguang wrote:
> On Mon, Nov 24, 2008 at 02:23:16PM +0200, Patrick McHardy wrote:
>> +	/* Avoid bogus warning, gcc doesn't realize do_basic_checks()
>> +	 * guarantees that there is at least one SCTP chunk.
>> +	 */
>> +	if (unlikely(new_state == SCTP_CONNTRACK_MAX))
>> +		goto out;
>> +
> 
> If do_basic_checks() guarantees that, why not Initialize new_state to 0?

Good point. I've replaced the patch by this one:


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commit 328bd8997dbb7184d5389e45c642af44ae6e9043
Author: Patrick McHardy <kaber@trash.net>
Date:   Mon Nov 24 13:44:55 2008 +0100

    netfilter: nf_conntrack_proto_sctp: avoid bogus warning
    
    net/netfilter/nf_conntrack_proto_sctp.c: In function 'sctp_packet':
    net/netfilter/nf_conntrack_proto_sctp.c:376: warning: array subscript is above array bounds
    
    gcc doesn't realize that do_basic_checks() guarantees that there is
    at least one valid chunk and thus new_state is never SCTP_CONNTRACK_MAX
    after the loop. Initialize to SCTP_CONNTRACK_NONE to avoid the warning.
    
    Based on patch by Wu Fengguang <wfg@linux.intel.com>
    
    Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index c2bd457..74e0379 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -317,7 +317,7 @@ static int sctp_packet(struct nf_conn *ct,
 		goto out;
 	}
 
-	old_state = new_state = SCTP_CONNTRACK_MAX;
+	old_state = new_state = SCTP_CONNTRACK_NONE;
 	write_lock_bh(&sctp_lock);
 	for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
 		/* Special cases of Verification tag check (Sec 8.5.1) */