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From: Thomas Haller <thaller@redhat.com>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: NetFilter <netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH nft 7/9] expression: cleanup expr_ops_by_type() and handle u32 input
Date: Fri, 22 Sep 2023 10:54:52 +0200	[thread overview]
Message-ID: <988c6c1bc2a2fff3d0ab65bdd5c7bdb9e09499a1.camel@redhat.com> (raw)
In-Reply-To: <ZQxQ2bDCBBZGGfAR@calendula>

On Thu, 2023-09-21 at 16:19 +0200, Pablo Neira Ayuso wrote:
> On Wed, Sep 20, 2023 at 09:28:29PM +0200, Thomas Haller wrote:
> 
> 
> > The check "if (value > (uint32_t) EXPR_MAX)" is only here to ensure
> > that nothing is lost while casting the uint32_t "value" to the enum
> > expr_types.
> 
> Is this cast really required? This is to handle the hypothetical case
> where EXPR_MAX ever gets a negative value?
> 

EXPR_MAX is never negative.

If EXPR_MAX is treated as a signed integer, then it will be implicitly
cast to unsigned when comparing with the uint32_t. The behavior will be
correct without a cast.

But won't the compiler warn about comparing integers of different
signedness?

The cast is probably not needed. But it doesn't hurt.


Thomas


  reply	other threads:[~2023-09-22  8:55 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20 14:26 [PATCH nft 0/9] various cleanups related to enums and struct datatype Thomas Haller
2023-09-20 14:26 ` [PATCH nft 1/9] src: fix indentation/whitespace Thomas Haller
2023-09-20 16:03   ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 2/9] include: fix missing definitions in <cache.h>/<headers.h> Thomas Haller
2023-09-20 14:26 ` [PATCH nft 3/9] datatype: drop flags field from datatype Thomas Haller
2023-09-20 18:10   ` Pablo Neira Ayuso
2023-09-20 19:23     ` Thomas Haller
2023-09-21 14:23       ` Pablo Neira Ayuso
2023-09-22  8:51         ` Thomas Haller
2023-09-22 11:18           ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 4/9] datatype: use "enum byteorder" instead of int in set_datatype_alloc() Thomas Haller
2023-09-20 16:27   ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 5/9] payload: use enum icmp_hdr_field_type in payload_may_dependency_kill_icmp() Thomas Haller
2023-09-20 16:32   ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 6/9] netlink: handle invalid etype in set_make_key() Thomas Haller
2023-09-20 16:22   ` Pablo Neira Ayuso
2023-09-20 16:24   ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 7/9] expression: cleanup expr_ops_by_type() and handle u32 input Thomas Haller
2023-09-20 18:13   ` Pablo Neira Ayuso
2023-09-20 19:28     ` Thomas Haller
2023-09-21 14:19       ` Pablo Neira Ayuso
2023-09-22  8:54         ` Thomas Haller [this message]
2023-09-22  9:56           ` Pablo Neira Ayuso
2023-09-25  8:44           ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 8/9] datatype: use __attribute__((packed)) instead of enum bitfields Thomas Haller
2023-09-20 16:02   ` Pablo Neira Ayuso
2023-09-20 17:48     ` Thomas Haller
2023-09-20 18:07       ` Pablo Neira Ayuso
2023-09-20 16:46   ` Pablo Neira Ayuso
2023-09-20 14:26 ` [PATCH nft 9/9] proto: add missing proto_definitions for PROTO_DESC_GENEVE Thomas Haller
2023-09-20 16:14   ` Pablo Neira Ayuso

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