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From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Jeremy Kerr <jk@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/7] powerpc/spufs: simplify spufs core dumping
Date: Tue, 21 Apr 2020 19:49:41 +0100
Message-ID: <20200421184941.GD23230@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200421154204.252921-2-hch@lst.de>

On Tue, Apr 21, 2020 at 05:41:58PM +0200, Christoph Hellwig wrote:

>  static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
>  				   size_t len, loff_t *pos)
>  {
>  	struct spu_context *ctx = file->private_data;
> +	struct spu_proxydma_info info;
>  	int ret;
>  
> +	if (len < sizeof(info))
> +		return -EINVAL;
> +	if (!access_ok(buf, len))
> +		return -EFAULT;
> +
>  	ret = spu_acquire_saved(ctx);
>  	if (ret)
>  		return ret;
>  	spin_lock(&ctx->csa.register_lock);
> -	ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
> +	__spufs_proxydma_info_read(ctx, &info);
> +	ret = simple_read_from_buffer(buf, len, pos, &info, sizeof(info));

IDGI...  What's that access_ok() for?  If you are using simple_read_from_buffer(),
the damn thing goes through copy_to_user().  Why bother with separate access_ok()
here?

  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 15:41 remove set_fs calls from the exec and coredump code v3 Christoph Hellwig
2020-04-21 15:41 ` [PATCH 1/7] powerpc/spufs: simplify spufs core dumping Christoph Hellwig
2020-04-21 18:49   ` Al Viro [this message]
2020-04-21 19:01     ` Christoph Hellwig
2020-04-21 19:19       ` Al Viro
2020-04-21 19:25         ` Al Viro
2020-04-21 15:41 ` [PATCH 2/7] signal: factor copy_siginfo_to_external32 from copy_siginfo_to_user32 Christoph Hellwig
2020-04-26  4:47   ` Andrew Morton
2020-04-26  7:40     ` Christoph Hellwig
2020-04-27 22:40       ` Andrew Morton
2020-04-28  7:09         ` Christoph Hellwig
2020-04-28  7:45           ` Christophe Leroy
2020-04-28  7:48             ` Christoph Hellwig
2020-04-28 19:56               ` [PATCH] fixup! " Arnd Bergmann
2020-04-29  6:17                 ` Christophe Leroy
2020-04-29  6:29                   ` Christoph Hellwig
2020-04-29  6:44                 ` Christoph Hellwig
2020-04-29  8:07                   ` Arnd Bergmann
2020-04-29  9:42                     ` Christoph Hellwig
2020-04-29 11:28                       ` Arnd Bergmann
2020-04-29 11:53                 ` Christoph Hellwig
2020-04-29 12:34                   ` Arnd Bergmann
2020-04-21 15:42 ` [PATCH 3/7] binfmt_elf: femove the set_fs in fill_siginfo_note Christoph Hellwig
2020-04-21 15:42 ` [PATCH 4/7] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Christoph Hellwig
2020-04-21 15:42 ` [PATCH 5/7] binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump Christoph Hellwig
2020-04-21 15:42 ` [PATCH 6/7] exec: simplify the copy_strings_kernel calling convention Christoph Hellwig
2020-04-21 15:42 ` [PATCH 7/7] exec: open code copy_string_kernel Christoph Hellwig

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