From: ebiederm@xmission.com (Eric W. Biederman)
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: lkml <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Alban Crequy <alban@kinvolk.io>,
Seth Forshee <seth.forshee@canonical.com>,
Sargun Dhillon <sargun@sargun.me>,
Dongsu Park <dongsu@kinvolk.io>,
"Serge E. Hallyn" <serge@hallyn.com>,
Miklos Szeredi <mszeredi@redhat.com>
Subject: Re: [PATCH] fuse: Ensure posix acls are translated outside of init_user_ns
Date: Tue, 29 May 2018 07:42:35 -0500 [thread overview]
Message-ID: <877enmskec.fsf@xmission.com> (raw)
In-Reply-To: <87wovubbdf.fsf@xmission.com> (Eric W. Biederman's message of "Wed, 23 May 2018 11:11:24 -0500")
ebiederm@xmission.com (Eric W. Biederman) writes:
> ebiederm@xmission.com (Eric W. Biederman) writes:
>
>> Ensure the translation happens by failing to read or write
>> posix acls when the filesystem has not indicated it supports
>> posix acls.
>>
>> This ensures that modern cached posix acl support is available
>> and used when dealing with posix acls. This is important
>> because only that path has the code to convernt the uids and
>> gids in posix acls into the user namespace of a fuse filesystem.
>>
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>
> ping.
>
> Miklos are you around where you can look at this?
Perhaps I got the wrong email address.
Ping?
>
>> Miklos after several attempts to handle this better last cycle. I
>> figure we should go with the stupid version for now. I think I know
>> how to do better but I don't want that to gate forward progress on
>> fully unprivileged fuse mounts. Especially as this is the last known
>> issue to deal with.
>>
>> fs/fuse/fuse_i.h | 1 +
>> fs/fuse/inode.c | 7 +++++++
>> fs/fuse/xattr.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 51 insertions(+)
>>
>> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
>> index f630951df8dc..5256ad333b05 100644
>> --- a/fs/fuse/fuse_i.h
>> +++ b/fs/fuse/fuse_i.h
>> @@ -985,6 +985,7 @@ ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
>> int fuse_removexattr(struct inode *inode, const char *name);
>> extern const struct xattr_handler *fuse_xattr_handlers[];
>> extern const struct xattr_handler *fuse_acl_xattr_handlers[];
>> +extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
>>
>> struct posix_acl;
>> struct posix_acl *fuse_get_acl(struct inode *inode, int type);
>> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
>> index 1643043d4fe5..22c76cf8c2e3 100644
>> --- a/fs/fuse/inode.c
>> +++ b/fs/fuse/inode.c
>> @@ -1100,6 +1100,13 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
>> file->f_cred->user_ns != sb->s_user_ns)
>> goto err_fput;
>>
>> + /*
>> + * If we are not in the initial user namespace posix
>> + * acls must be translated.
>> + */
>> + if (sb->s_user_ns != &init_user_ns)
>> + sb->s_xattr = fuse_no_acl_xattr_handlers;
>> +
>> fc = kmalloc(sizeof(*fc), GFP_KERNEL);
>> err = -ENOMEM;
>> if (!fc)
>> diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
>> index 3caac46b08b0..433717640f78 100644
>> --- a/fs/fuse/xattr.c
>> +++ b/fs/fuse/xattr.c
>> @@ -192,6 +192,26 @@ static int fuse_xattr_set(const struct xattr_handler *handler,
>> return fuse_setxattr(inode, name, value, size, flags);
>> }
>>
>> +static bool no_xattr_list(struct dentry *dentry)
>> +{
>> + return false;
>> +}
>> +
>> +static int no_xattr_get(const struct xattr_handler *handler,
>> + struct dentry *dentry, struct inode *inode,
>> + const char *name, void *value, size_t size)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +
>> +static int no_xattr_set(const struct xattr_handler *handler,
>> + struct dentry *dentry, struct inode *nodee,
>> + const char *name, const void *value,
>> + size_t size, int flags)
>> +{
>> + return -EOPNOTSUPP;
>> +}
>> +
>> static const struct xattr_handler fuse_xattr_handler = {
>> .prefix = "",
>> .get = fuse_xattr_get,
>> @@ -209,3 +229,26 @@ const struct xattr_handler *fuse_acl_xattr_handlers[] = {
>> &fuse_xattr_handler,
>> NULL
>> };
>> +
>> +static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
>> + .name = XATTR_NAME_POSIX_ACL_ACCESS,
>> + .flags = ACL_TYPE_ACCESS,
>> + .list = no_xattr_list,
>> + .get = no_xattr_get,
>> + .set = no_xattr_set,
>> +};
>> +
>> +static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
>> + .name = XATTR_NAME_POSIX_ACL_DEFAULT,
>> + .flags = ACL_TYPE_ACCESS,
>> + .list = no_xattr_list,
>> + .get = no_xattr_get,
>> + .set = no_xattr_set,
>> +};
>> +
>> +const struct xattr_handler *fuse_no_acl_xattr_handlers[] = {
>> + &fuse_no_acl_access_xattr_handler,
>> + &fuse_no_acl_default_xattr_handler,
>> + &fuse_xattr_handler,
>> + NULL
>> +};
next prev parent reply other threads:[~2018-05-29 12:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-04 16:47 [PATCH] fuse: Ensure posix acls are translated outside of init_user_ns Eric W. Biederman
2018-05-08 13:37 ` Seth Forshee
2018-05-23 16:11 ` Eric W. Biederman
2018-05-29 12:42 ` Eric W. Biederman [this message]
2018-05-29 12:55 ` Miklos Szeredi
2018-05-29 14:02 ` Eric W. Biederman
2018-05-29 14:04 ` [PATCH] fuse: Allow fully unprivileged mounts Eric W. Biederman
2018-05-31 14:45 ` Miklos Szeredi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=877enmskec.fsf@xmission.com \
--to=ebiederm@xmission.com \
--cc=alban@kinvolk.io \
--cc=containers@lists.linux-foundation.org \
--cc=dongsu@kinvolk.io \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=mszeredi@redhat.com \
--cc=sargun@sargun.me \
--cc=serge@hallyn.com \
--cc=seth.forshee@canonical.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).