From: Jason Gunthorpe <jgg@ziepe.ca>
To: Kees Cook <keescook@chromium.org>
Cc: Erick Archer <erick.archer@gmx.com>,
Leon Romanovsky <leon@kernel.org>,
Edward Srouji <edwards@nvidia.com>,
Patrisious Haddad <phaddad@nvidia.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] RDMA/uverbs: Remove flexible arrays from struct *_filter
Date: Mon, 12 Feb 2024 14:59:56 -0400 [thread overview]
Message-ID: <20240212185956.GH765010@ziepe.ca> (raw)
In-Reply-To: <202402121026.0AF90DBA@keescook>
On Mon, Feb 12, 2024 at 10:30:17AM -0800, Kees Cook wrote:
> I might suggest doing a binary difference comparison[1], as it's possible
> that "real_sz" is being used to try to avoid trailing padding on
> structs. I wasn't able to trivially construct an example, so maybe I'm
> not understanding its purpose correctly.
Hmm.. No need for binary comparison:
+static_assert(offsetof(struct ib_flow_eth_filter, real_sz) == sizeof(struct ib_flow_eth_filter));
+static_assert(offsetof(struct ib_flow_ib_filter, real_sz) == sizeof(struct ib_flow_ib_filter));
+static_assert(offsetof(struct ib_flow_tunnel_filter, real_sz) == sizeof(struct ib_flow_tunnel_filter));
+static_assert(offsetof(struct ib_flow_esp_filter, real_sz) == sizeof(struct ib_flow_esp_filter));
+static_assert(offsetof(struct ib_flow_gre_filter, real_sz) == sizeof(struct ib_flow_gre_filter));
+static_assert(offsetof(struct ib_flow_mpls_filter, real_sz) == sizeof(struct ib_flow_mpls_filter));
But yep, it is doing something:
In file included from ../include/linux/mlx5/device.h:37:
../include/rdma/ib_verbs.h:1931:15: error: static assertion failed due to requirement '__builtin_offsetof(struct ib_flow_ib_filter, real_sz) == sizeof(struct ib_flow_ib_filter)': offsetof(struct ib_flow_ib_filter, real_sz) == sizeof(struct ib_flow_ib_filter)
1931 | static_assert(offsetof(struct ib_flow_ib_filter, real_sz) == sizeof(struct ib_flow_ib_filter));
__packed on that struct would probably be be OK.
Jason
prev parent reply other threads:[~2024-02-12 18:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-11 11:58 [PATCH] RDMA/uverbs: Remove flexible arrays from struct *_filter Erick Archer
2024-02-12 18:30 ` Kees Cook
2024-02-12 18:59 ` Jason Gunthorpe [this message]
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