linux-kernel - Re: [PATCH 01/25] userns: Convert fat to use kuid/kgid where appropriate

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Message-ID: <87pq5gx60i.fsf@devron.myhome.or.jp>
Date:	Thu, 20 Sep 2012 20:55:57 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	<linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Serge Hallyn <serge@...lyn.com>,
	Linux Containers <containers@...ts.linux-foundation.org>
Subject: Re: [PATCH 01/25] userns: Convert fat to use kuid/kgid where appropriate

"Eric W. Biederman" <ebiederm@...ssion.com> writes:

>  struct fat_mount_options {
> -	uid_t fs_uid;
> -	gid_t fs_gid;
> +	kuid_t fs_uid;
> +	kgid_t fs_gid;
>  	unsigned short fs_fmask;
>  	unsigned short fs_dmask;
>  	unsigned short codepage;  /* Codepage for shortname conversions */

I'm not reading this thread, so I may be wrong though. Doesn't this need
to initialize opts->fs_uid/fs_gid by GLOBAL_ROOT_UID/GID?

> diff --git a/fs/fat/file.c b/fs/fat/file.c
> index e007b8b..a62e0ec 100644
> --- a/fs/fat/file.c
> +++ b/fs/fat/file.c
> @@ -352,7 +352,7 @@ static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
>  {
>  	umode_t allow_utime = sbi->options.allow_utime;
>  
> -	if (current_fsuid() != inode->i_uid) {
> +	if (!uid_eq(current_fsuid(), inode->i_uid)) {
>  		if (in_group_p(inode->i_gid))
>  			allow_utime >>= 3;
>  		if (allow_utime & MAY_WRITE)
> @@ -407,9 +407,9 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
>  	}
>  
>  	if (((attr->ia_valid & ATTR_UID) &&
> -	     (attr->ia_uid != sbi->options.fs_uid)) ||
> +	     (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) ||
>  	    ((attr->ia_valid & ATTR_GID) &&
> -	     (attr->ia_gid != sbi->options.fs_gid)) ||
> +	     (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) ||
>  	    ((attr->ia_valid & ATTR_MODE) &&
>  	     (attr->ia_mode & ~FAT_VALID_MODE)))
>  		error = -EPERM;
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 05e897f..47d9eb0 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -791,10 +791,12 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
>  	struct fat_mount_options *opts = &sbi->options;
>  	int isvfat = opts->isvfat;
>  
> -	if (opts->fs_uid != 0)
> -		seq_printf(m, ",uid=%u", opts->fs_uid);
> -	if (opts->fs_gid != 0)
> -		seq_printf(m, ",gid=%u", opts->fs_gid);
> +	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
> +		seq_printf(m, ",uid=%u",
> +				from_kuid_munged(&init_user_ns, opts->fs_uid));
> +	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
> +		seq_printf(m, ",gid=%u",
> +				from_kgid_munged(&init_user_ns, opts->fs_gid));
>  	seq_printf(m, ",fmask=%04o", opts->fs_fmask);
>  	seq_printf(m, ",dmask=%04o", opts->fs_dmask);
>  	if (opts->allow_utime)
> @@ -1037,12 +1039,16 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
>  		case Opt_uid:
>  			if (match_int(&args[0], &option))
>  				return 0;
> -			opts->fs_uid = option;
> +			opts->fs_uid = make_kuid(current_user_ns(), option);
> +			if (!uid_valid(opts->fs_uid))
> +				return 0;
>  			break;
>  		case Opt_gid:
>  			if (match_int(&args[0], &option))
>  				return 0;
> -			opts->fs_gid = option;
> +			opts->fs_gid = make_kgid(current_user_ns(), option);
> +			if (!gid_valid(opts->fs_gid))
> +				return 0;
>  			break;
>  		case Opt_umask:
>  			if (match_octal(&args[0], &option))
> diff --git a/init/Kconfig b/init/Kconfig
> index 296d48b..60bdff2 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -952,7 +952,6 @@ config UIDGID_CONVERTED
>  	depends on ECRYPT_FS = n
>  	depends on EFS_FS = n
>  	depends on EXOFS_FS = n
> -	depends on FAT_FS = n
>  	depends on FUSE_FS = n
>  	depends on GFS2_FS = n
>  	depends on HFS_FS = n

-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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