Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759577Ab3EGSNY (ORCPT ); Tue, 7 May 2013 14:13:24 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:6745 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753225Ab3EGSNW (ORCPT ); Tue, 7 May 2013 14:13:22 -0400 X-Authority-Analysis: v=2.0 cv=UY7TuduN c=1 sm=0 a=tLUlnkoJZcZI9ocdGARlSQ==:17 a=c11ml42nfjYA:10 a=wom5GMh1gUkA:10 a=ce83iNt2u7sA:10 a=Rj1_iGo3bfgA:10 a=kj9zAlcOel0A:10 a=hBqU3vQJAAAA:8 a=4DsXJwEFsZQA:10 a=VnNF1IyMAAAA:8 a=DfNHnWVPAAAA:8 a=PtDNVHqPAAAA:8 a=VwQbUJbxAAAA:8 a=W0vUJOdyAAAA:8 a=5rdOox-fF5QFgpDjjLcA:9 a=CjuIK1q_8ugA:10 a=x8gzFH9gYPwA:10 a=lBRciGGoxdUA:10 a=wYE_KDyynt4A:10 a=tLUlnkoJZcZI9ocdGARlSQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 70.114.148.7 Date: Tue, 7 May 2013 13:14:24 -0500 From: "Serge E. Hallyn" To: Miklos Szeredi Cc: raven@themaw.net, autofs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, sukadev@linux.vnet.ibm.com, serge.hallyn@canonical.com, ebiederm@xmission.com Subject: Re: [PATCH 1/2] autofs4: allow autofs to work outside the initial PID namespace Message-ID: <20130507181424.GA12315@austin.hallyn.com> References: <20130507135446.GA6129@tucsk.piliscsaba.szeredi.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130507135446.GA6129@tucsk.piliscsaba.szeredi.hu> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7438 Lines: 225 Quoting Miklos Szeredi (miklos@szeredi.hu): > From: Sukadev Bhattiprolu > > This patch enables autofs4 to work in a "container". oz_pgrp is converted from > pid_t to struct pid and this is stored at mount time based on the "pgrp=" option > or if the option is missing then the current pgrp. > > The "pgrp=" option is interpreted in the PID namespace of the current process. > This option is flawed in that it doesn't carry the namespace information, so it > should be deprecated. AFAICS the autofs daemon always sends the current pgrp, > which is the default anyway. > > The oz_pgrp is also set from the AUTOFS_DEV_IOCTL_SETPIPEFD_CMD ioctl. This > ioctl sets oz_pgrp to the current pgrp. It is not allowed to change the pid > namespace. > > oz_pgrp is used mainly to determine whether the process traversing the autofs > mount tree is the autofs daemon itself or not. This function now compares the > pid pointers instead of the pid_t values. > > One other use of oz_pgrp is in autofs4_show_options. There is shows the > virtual pid number (i.e. the one that is valid inside the PID namespace of the > calling process) > > For debugging printk convert oz_pgrp to the value in the initial pid namespace. > > Signed-off-by: Sukadev Bhattiprolu > Cc: Serge Hallyn Haven't tested, but it looks good to me. Acked-by: Serge Hallyn > Cc: Eric Biederman > Signed-off-by: Miklos Szeredi > --- > fs/autofs4/autofs_i.h | 4 ++-- > fs/autofs4/dev-ioctl.c | 16 ++++++++++++++-- > fs/autofs4/inode.c | 33 +++++++++++++++++++++++++-------- > 3 files changed, 41 insertions(+), 12 deletions(-) > > --- a/fs/autofs4/autofs_i.h > +++ b/fs/autofs4/autofs_i.h > @@ -104,7 +104,7 @@ struct autofs_sb_info { > u32 magic; > int pipefd; > struct file *pipe; > - pid_t oz_pgrp; > + struct pid *oz_pgrp; > int catatonic; > int version; > int sub_version; > @@ -139,7 +139,7 @@ static inline struct autofs_info *autofs > filesystem without "magic".) */ > > static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) { > - return sbi->catatonic || task_pgrp_nr(current) == sbi->oz_pgrp; > + return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp; > } > > /* Does a dentry have some pending activity? */ > --- a/fs/autofs4/inode.c > +++ b/fs/autofs4/inode.c > @@ -62,6 +62,8 @@ void autofs4_kill_sb(struct super_block > /* Free wait queues, close pipe */ > autofs4_catatonic_mode(sbi); > > + put_pid(sbi->oz_pgrp); > + > sb->s_fs_info = NULL; > kfree(sbi); > > @@ -85,7 +87,7 @@ static int autofs4_show_options(struct s > if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID)) > seq_printf(m, ",gid=%u", > from_kgid_munged(&init_user_ns, root_inode->i_gid)); > - seq_printf(m, ",pgrp=%d", sbi->oz_pgrp); > + seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp)); > seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ); > seq_printf(m, ",minproto=%d", sbi->min_proto); > seq_printf(m, ",maxproto=%d", sbi->max_proto); > @@ -129,7 +131,8 @@ static const match_table_t tokens = { > }; > > static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid, > - pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto) > + int *pgrp, bool *pgrp_set, unsigned int *type, > + int *minproto, int *maxproto) > { > char *p; > substring_t args[MAX_OPT_ARGS]; > @@ -137,7 +140,6 @@ static int parse_options(char *options, > > *uid = current_uid(); > *gid = current_gid(); > - *pgrp = task_pgrp_nr(current); > > *minproto = AUTOFS_MIN_PROTO_VERSION; > *maxproto = AUTOFS_MAX_PROTO_VERSION; > @@ -176,6 +178,7 @@ static int parse_options(char *options, > if (match_int(args, &option)) > return 1; > *pgrp = option; > + *pgrp_set = true; > break; > case Opt_minproto: > if (match_int(args, &option)) > @@ -211,6 +214,8 @@ int autofs4_fill_super(struct super_bloc > int pipefd; > struct autofs_sb_info *sbi; > struct autofs_info *ino; > + int pgrp; > + bool pgrp_set = false; > > sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); > if (!sbi) > @@ -223,7 +228,7 @@ int autofs4_fill_super(struct super_bloc > sbi->pipe = NULL; > sbi->catatonic = 1; > sbi->exp_timeout = 0; > - sbi->oz_pgrp = task_pgrp_nr(current); > + sbi->oz_pgrp = NULL; > sbi->sb = s; > sbi->version = 0; > sbi->sub_version = 0; > @@ -260,12 +265,23 @@ int autofs4_fill_super(struct super_bloc > > /* Can this call block? */ > if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid, > - &sbi->oz_pgrp, &sbi->type, &sbi->min_proto, > - &sbi->max_proto)) { > + &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto, > + &sbi->max_proto)) { > printk("autofs: called with bogus options\n"); > goto fail_dput; > } > > + if (pgrp_set) { > + sbi->oz_pgrp = find_get_pid(pgrp); > + if (!sbi->oz_pgrp) { > + pr_warn("autofs: could not find process group %d\n", > + pgrp); > + goto fail_dput; > + } > + } else { > + sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID); > + } > + > if (autofs_type_trigger(sbi->type)) > __managed_dentry_set_managed(root); > > @@ -289,9 +305,9 @@ int autofs4_fill_super(struct super_bloc > sbi->version = sbi->max_proto; > sbi->sub_version = AUTOFS_PROTO_SUBVERSION; > > - DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp); > + DPRINTK("pipe fd = %d, pgrp = %u", pipefd, pid_nr(sbi->oz_pgrp)); > pipe = fget(pipefd); > - > + > if (!pipe) { > printk("autofs: could not open pipe file descriptor\n"); > goto fail_dput; > @@ -321,6 +337,7 @@ int autofs4_fill_super(struct super_bloc > fail_ino: > kfree(ino); > fail_free: > + put_pid(sbi->oz_pgrp); > kfree(sbi); > s->s_fs_info = NULL; > fail_unlock: > --- a/fs/autofs4/dev-ioctl.c > +++ b/fs/autofs4/dev-ioctl.c > @@ -346,6 +346,7 @@ static int autofs_dev_ioctl_setpipefd(st > { > int pipefd; > int err = 0; > + struct pid *new_pid = NULL; > > if (param->setpipefd.pipefd == -1) > return -EINVAL; > @@ -357,7 +358,17 @@ static int autofs_dev_ioctl_setpipefd(st > mutex_unlock(&sbi->wq_mutex); > return -EBUSY; > } else { > - struct file *pipe = fget(pipefd); > + struct file *pipe; > + > + new_pid = get_task_pid(current, PIDTYPE_PGID); > + > + if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) { > + AUTOFS_WARN("Not allowed to change PID namespace"); > + err = -EINVAL; > + goto out; > + } > + > + pipe = fget(pipefd); > if (!pipe) { > err = -EBADF; > goto out; > @@ -367,12 +378,13 @@ static int autofs_dev_ioctl_setpipefd(st > fput(pipe); > goto out; > } > - sbi->oz_pgrp = task_pgrp_nr(current); > + swap(sbi->oz_pgrp, new_pid); > sbi->pipefd = pipefd; > sbi->pipe = pipe; > sbi->catatonic = 0; > } > out: > + put_pid(new_pid); > mutex_unlock(&sbi->wq_mutex); > return err; > } > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/