linux-kernel - Re: [PATCH] proc: smoke test lseek()

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: <20210407195809.GG2531743@casper.infradead.org>
Date:   Wed, 7 Apr 2021 20:58:09 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH] proc: smoke test lseek()

On Wed, Apr 07, 2021 at 10:55:14PM +0300, Alexey Dobriyan wrote:
> Now that ->proc_lseek has been made mandatory it would be nice to test
> that nothing has been forgotten.

> @@ -45,6 +45,8 @@ static void f_reg(DIR *d, const char *filename)
>  	fd = openat(dirfd(d), filename, O_RDONLY|O_NONBLOCK);
>  	if (fd == -1)
>  		return;
> +	/* struct proc_ops::proc_lseek is mandatory if file is seekable. */
> +	(void)lseek(fd, 0, SEEK_SET);
>  	rv = read(fd, buf, sizeof(buf));
>  	assert((0 <= rv && rv <= sizeof(buf)) || rv == -1);
>  	close(fd);

why throw away the return value?  if it returns an error seeking to
offset 0, something is terribly wrong.