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Biederman) To: Miklos Szeredi Cc: Dongsu Park , lkml , Linux Containers , Alban Crequy , Seth Forshee , Sargun Dhillon , linux-fsdevel , Alexander Viro References: <61a37f0b159dd56825696d8d3beb8eaffdf1f72f.1512041070.git.dongsu@kinvolk.io> Date: Mon, 19 Feb 2018 16:56:56 -0600 In-Reply-To: (Miklos Szeredi's message of "Wed, 14 Feb 2018 13:28:12 +0100") Message-ID: <87mv04mvuv.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1enuN6-00028G-Kb;;;mid=<87mv04mvuv.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=174.19.85.160;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19p8dqWSB+bJ3PmBuoZvZQPIEgJRBx/rwk= X-SA-Exim-Connect-IP: 174.19.85.160 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on sa04.xmission.com X-Spam-Level: ** X-Spam-Status: No, score=2.0 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,TVD_RCVD_IP,T_TM2_M_HEADER_IN_MSG,T_TooManySym_01, XMNoVowels,XMSubLong autolearn=disabled version=3.4.1 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.7 XMSubLong Long Subject * 0.0 TVD_RCVD_IP Message was received from an IP address * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa04 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa04 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Miklos Szeredi X-Spam-Relay-Country: X-Spam-Timing: total 271 ms - load_scoreonly_sql: 0.06 (0.0%), signal_user_changed: 4.0 (1.5%), b_tie_ro: 2.9 (1.1%), parse: 1.40 (0.5%), extract_message_metadata: 23 (8.6%), get_uri_detail_list: 2.8 (1.0%), tests_pri_-1000: 12 (4.4%), tests_pri_-950: 1.75 (0.6%), tests_pri_-900: 1.48 (0.5%), tests_pri_-400: 22 (8.2%), check_bayes: 21 (7.7%), b_tokenize: 8 (2.9%), b_tok_get_all: 6 (2.2%), b_comp_prob: 2.4 (0.9%), b_tok_touch_all: 2.3 (0.8%), b_finish: 0.71 (0.3%), tests_pri_0: 137 (50.7%), check_dkim_signature: 0.56 (0.2%), check_dkim_adsp: 3.0 (1.1%), tests_pri_500: 63 (23.2%), poll_dns_idle: 54 (20.1%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH 07/11] fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miklos Szeredi writes: > On Fri, Dec 22, 2017 at 3:32 PM, Dongsu Park wrote: >> From: Seth Forshee >> >> The user in control of a super block should be allowed to freeze >> and thaw it. Relax the restrictions on the FIFREEZE and FITHAW >> ioctls to require CAP_SYS_ADMIN in s_user_ns. > > Why is this required for unprivileged fuse? > > Fuse doesn't support freeze, so this seems to make no sense in the > context of this patchset. This isn't required to support fuse. It is a relaxation in permissions so it isn't strictly necessary for anything. Until just recently Seth and I work working through the vfs looking at what we need in general for unprivileged mounts. With fuse as our focus but we were not limiting ourselves to fuse. I have been putting off relaxation of permissions like this because they are not necessary for safety. But in general they do make sense. In practice I think all we need to worry about for fuse is the last 4 patches. Eric