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Date: Wed, 16 Aug 2017 17:05:02 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, Nick Kralevich <nnk@google.com>,
        Sebastian Schmidt <yath@yath.de>, Tony Luck <tony.luck@intel.com>,
        Anton Vorontsov <anton@enomsg.org>, Colin Cross <ccross@android.com>,
        Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Patrick Tjin <pattjin@google.com>, Mark Salyzyn <salyzyn@google.com>
Subject: Re: [PATCH 1/2] pstore: Make default pstorefs root dir perms 0750
Message-ID: <20170816080502.GD522@jagdpanzerIV.localdomain>
References: <1502397395-118652-1-git-send-email-keescook@chromium.org>
 <1502397395-118652-2-git-send-email-keescook@chromium.org>
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Hello,

On (08/10/17 13:36), Kees Cook wrote:
> Currently only DMESG and CONSOLE record types are protected, and it isn't
> obvious that they are using a capability check. Instead switch to explicit
> root directory mode of 0750 to keep files private by default.  This will
> allow the removal of the capability check, which was non-obvious and
> forces a process to have possibly too much privilege

it's CAP_SYSLOG, isn't it? is it too much? does chgrp require less privileges?

	-ss

> when simple post-boot chgrp for readers would be possible without it.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  fs/pstore/inode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
> index fefd22611cf6..f1e88b695090 100644
> --- a/fs/pstore/inode.c
> +++ b/fs/pstore/inode.c
> @@ -471,7 +471,7 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
>  
>  	inode = pstore_get_inode(sb);
>  	if (inode) {
> -		inode->i_mode = S_IFDIR | 0755;
> +		inode->i_mode = S_IFDIR | 0750;
>  		inode->i_op = &pstore_dir_inode_operations;
>  		inode->i_fop = &simple_dir_operations;
>  		inc_nlink(inode);
> -- 
> 2.7.4
>