netdev - Re: [PATCH v2 1/4][next] uapi: socket: Introduce struct sockaddr

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: <202410281632.1AFBD73@keescook>
Date: Mon, 28 Oct 2024 16:34:48 -0700
From: Kees Cook <kees@...nel.org>
To: "Gustavo A. R. Silva" <gustavoars@...nel.org>
Cc: Andrew Lunn <andrew+netdev@...n.ch>,
	Johannes Berg <johannes@...solutions.net>,
	David Ahern <dsahern@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-hardening@...r.kernel.org, Simon Horman <horms@...nel.org>
Subject: Re: [PATCH v2 1/4][next] uapi: socket: Introduce struct
 sockaddr_legacy

On Thu, Oct 24, 2024 at 03:11:24PM -0600, Gustavo A. R. Silva wrote:
> diff --git a/include/uapi/linux/socket.h b/include/uapi/linux/socket.h
> index d3fcd3b5ec53..2e179706bec4 100644
> --- a/include/uapi/linux/socket.h
> +++ b/include/uapi/linux/socket.h
> @@ -35,4 +35,32 @@ struct __kernel_sockaddr_storage {
>  #define SOCK_TXREHASH_DISABLED	0
>  #define SOCK_TXREHASH_ENABLED	1
>  
> +typedef __kernel_sa_family_t    sa_family_t;
> +
> +/*
> + * This is the legacy form of `struct sockaddr`. The original `struct sockaddr`
> + * was modified in commit b5f0de6df6dce ("net: dev: Convert sa_data to flexible
> + * array in struct sockaddr") due to the fact that "One of the worst offenders
> + * of "fake flexible arrays" is struct sockaddr". This means that the original
> + * `char sa_data[14]` behaved as a flexible array at runtime, so a proper
> + * flexible-array member was introduced.
> + *
> + * This caused several flexible-array-in-the-middle issues:
> + * https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wflex-array-member-not-at-end
> + *
> + * `struct sockaddr_legacy` replaces `struct sockaddr` in all instances where
> + * objects of this type do not appear at the end of composite structures.
> + */
> +struct sockaddr_legacy {
> +        sa_family_t     sa_family;      /* address family, AF_xxx       */
> +        char            sa_data[14];    /* 14 bytes of protocol address */
> +};
> +
> +#ifdef __KERNEL__
> +#	define __kernel_sockaddr_legacy		sockaddr_legacy
> +#else
> +#	define __kernel_sockaddr_legacy		sockaddr
> +#endif

Yeah, this matches what I'd expect.

Reviewed-by: Kees Cook <kees@...nel.org>

-- 
Kees Cook