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Subject[PATCH 1/3] implement uid and gid mount options for ext2
Date
Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>
---
Documentation/filesystems/ext2.txt | 9 ++++
fs/ext2/ext2.h | 8 +++
fs/ext2/inode.c | 48 +++++++++++++-----
fs/ext2/super.c | 95 +++++++++++++++++++++++++++++++++++-
4 Dateien geändert, 147 Zeilen hinzugefügt(+), 13 Zeilen entfernt(-)
diff --git a/Documentation/filesystems/ext2.txt b/Documentation/filesystems/ext2.txt
index 67639f9..fcc1002 100644
--- a/Documentation/filesystems/ext2.txt
+++ b/Documentation/filesystems/ext2.txt
@@ -42,6 +42,15 @@ orlov (*) Use the Orlov block allocator.
resuid=n The user ID which may use the reserved blocks.
resgid=n The group ID which may use the reserved blocks.

+uid=n[:m] Make all files appear to belong to uid n.
+ Useful for e.g. removable media with fstab
+ options 'user,uid=useruid'. The optional second
+ uid m is actually written to the file system.
+
+gid=n[:m] Make all files appear to belong to gid n.
+ The optional second gid m is actually written to
+ the file system.
+
sb=n Use alternate superblock at this location.

user_xattr Enable "user." POSIX Extended Attributes
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index d9a17d0..160d5d8 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -84,6 +84,10 @@ struct ext2_sb_info {
unsigned long s_sb_block;
kuid_t s_resuid;
kgid_t s_resgid;
+ kuid_t s_uid; /* make all files appear to belong to this uid */
+ kuid_t s_diskuid; /* write this uid to disk (if s_uid != 0) */
+ kgid_t s_gid; /* make all files appear to belong to this gid */
+ kgid_t s_diskgid; /* write this gid to disk (if s_gid != 0) */
unsigned short s_mount_state;
unsigned short s_pad;
int s_addr_per_block_bits;
@@ -639,6 +643,10 @@ struct ext2_mount_options {
unsigned long s_mount_opt;
kuid_t s_resuid;
kgid_t s_resgid;
+ kuid_t s_uid;
+ kuid_t s_diskuid;
+ kgid_t s_gid;
+ kgid_t s_diskgid;
};

/*
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 6363ac6..b2320e4 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1321,8 +1321,14 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
}
- i_uid_write(inode, i_uid);
- i_gid_write(inode, i_gid);
+ if (uid_valid(EXT2_SB(sb)->s_uid))
+ inode->i_uid = EXT2_SB(sb)->s_uid;
+ else
+ i_uid_write(inode, i_uid);
+ if (gid_valid(EXT2_SB(sb)->s_gid))
+ inode->i_gid = EXT2_SB(sb)->s_gid;
+ else
+ i_gid_write(inode, i_gid);
set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
inode->i_size = le32_to_cpu(raw_inode->i_size);
inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
@@ -1426,6 +1432,10 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
int n;
int err = 0;
+ __le16 uid_low;
+ __le16 gid_low;
+ __le16 uid_high;
+ __le16 gid_high;

if (IS_ERR(raw_inode))
return -EIO;
@@ -1437,26 +1447,40 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)

ext2_get_inode_flags(ei);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+ if (uid_valid(EXT2_SB(sb)->s_uid))
+ uid = from_kuid(&init_user_ns, EXT2_SB(sb)->s_diskuid);
+ if (gid_valid(EXT2_SB(sb)->s_gid))
+ gid = from_kgid(&init_user_ns, EXT2_SB(sb)->s_diskgid);
if (!(test_opt(sb, NO_UID32))) {
- raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
- raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
+ uid_low = cpu_to_le16(low_16_bits(uid));
+ gid_low = cpu_to_le16(low_16_bits(gid));
/*
* Fix up interoperability with old kernels. Otherwise, old inodes get
* re-used with the upper 16 bits of the uid/gid intact
*/
if (!ei->i_dtime) {
- raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
- raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
+ uid_high = cpu_to_le16(high_16_bits(uid));
+ gid_high = cpu_to_le16(high_16_bits(gid));
} else {
- raw_inode->i_uid_high = 0;
- raw_inode->i_gid_high = 0;
+ uid_high = 0;
+ gid_high = 0;
}
} else {
- raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
- raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
- raw_inode->i_uid_high = 0;
- raw_inode->i_gid_high = 0;
+ uid_low = cpu_to_le16(fs_high2lowuid(uid));
+ gid_low = cpu_to_le16(fs_high2lowgid(gid));
+ uid_high = 0;
+ gid_high = 0;
+ }
+ /* don't mangle uid/gid of existing files if override is active */
+ if (!uid_valid(EXT2_SB(sb)->s_uid) || ei->i_state & EXT2_STATE_NEW) {
+ raw_inode->i_uid_high = uid_high;
+ raw_inode->i_uid_low = uid_low;
}
+ if (!gid_valid(EXT2_SB(sb)->s_gid) || ei->i_state & EXT2_STATE_NEW) {
+ raw_inode->i_gid_high = gid_high;
+ raw_inode->i_gid_low = gid_low;
+ }
+
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
raw_inode->i_size = cpu_to_le32(inode->i_size);
raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index af74d9e..0f91dfb 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -237,6 +237,24 @@ static int ext2_show_options(struct seq_file *seq, struct dentry *root)
seq_printf(seq, ",resgid=%u",
from_kgid_munged(&init_user_ns, sbi->s_resgid));
}
+ if (uid_valid(sbi->s_uid)) {
+ if (!uid_eq(sbi->s_uid, sbi->s_diskuid))
+ seq_printf(seq, ",uid=%u:%u",
+ from_kuid_munged(&init_user_ns, sbi->s_uid),
+ from_kuid_munged(&init_user_ns, sbi->s_diskuid));
+ else
+ seq_printf(seq, ",uid=%u",
+ from_kuid_munged(&init_user_ns, sbi->s_uid));
+ }
+ if (gid_valid(sbi->s_gid)) {
+ if (!gid_eq(sbi->s_gid, sbi->s_diskgid))
+ seq_printf(seq, ",gid=%u:%u",
+ from_kgid_munged(&init_user_ns, sbi->s_gid),
+ from_kgid_munged(&init_user_ns, sbi->s_diskgid));
+ else
+ seq_printf(seq, ",gid=%u",
+ from_kgid_munged(&init_user_ns, sbi->s_gid));
+ }
if (test_opt(sb, ERRORS_RO)) {
int def_errors = le16_to_cpu(es->s_errors);

@@ -390,7 +408,8 @@ enum {
Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
- Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
+ Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation,
+ Opt_uid, Opt_diskuid, Opt_gid, Opt_diskgid
};

static const match_table_t tokens = {
@@ -424,6 +443,10 @@ static const match_table_t tokens = {
{Opt_usrquota, "usrquota"},
{Opt_reservation, "reservation"},
{Opt_noreservation, "noreservation"},
+ {Opt_uid, "uid=%u"},
+ {Opt_diskuid, "uid=%u:%u"},
+ {Opt_gid, "gid=%u"},
+ {Opt_diskgid, "gid=%u:%u"},
{Opt_err, NULL}
};

@@ -578,6 +601,64 @@ static int parse_options(char *options, struct super_block *sb)
clear_opt(sbi->s_mount_opt, RESERVATION);
ext2_msg(sb, KERN_INFO, "reservations OFF");
break;
+ case Opt_uid:
+ if (match_int(&args[0], &option))
+ return 0;
+ uid = make_kuid(current_user_ns(), option);
+ if (!uid_valid(uid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
+ return -1;
+ }
+ sbi->s_uid = sbi->s_diskuid = uid;
+ break;
+ case Opt_diskuid:
+ if (match_int(&args[0], &option))
+ return 0;
+ uid = make_kuid(current_user_ns(), option);
+ if (!uid_valid(uid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
+ return -1;
+ }
+ sbi->s_uid = uid;
+
+ if (match_int(&args[1], &option))
+ return 0;
+ uid = make_kuid(current_user_ns(), option);
+ if (!uid_valid(uid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
+ return -1;
+ }
+ sbi->s_diskuid = uid;
+ break;
+ case Opt_gid:
+ if (match_int(&args[0], &option))
+ return 0;
+ gid = make_kgid(current_user_ns(), option);
+ if (!gid_valid(gid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
+ return -1;
+ }
+ sbi->s_gid = sbi->s_diskgid = gid;
+ break;
+ case Opt_diskgid:
+ if (match_int(&args[0], &option))
+ return 0;
+ gid = make_kgid(current_user_ns(), option);
+ if (!gid_valid(gid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
+ return -1;
+ }
+ sbi->s_gid = gid;
+
+ if (match_int(&args[1], &option))
+ return 0;
+ gid = make_kgid(current_user_ns(), option);
+ if (!gid_valid(gid)) {
+ ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
+ return -1;
+ }
+ sbi->s_diskgid = gid;
+ break;
case Opt_ignore:
break;
default:
@@ -853,6 +934,10 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)

sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
+ sbi->s_uid = INVALID_UID;
+ sbi->s_gid = INVALID_GID;
+ sbi->s_diskuid = INVALID_UID;
+ sbi->s_diskgid = INVALID_GID;

set_opt(sbi->s_mount_opt, RESERVATION);

@@ -1256,6 +1341,10 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
old_opts.s_mount_opt = sbi->s_mount_opt;
old_opts.s_resuid = sbi->s_resuid;
old_opts.s_resgid = sbi->s_resgid;
+ old_opts.s_uid = sbi->s_uid;
+ old_opts.s_diskuid = sbi->s_diskuid;
+ old_opts.s_gid = sbi->s_gid;
+ old_opts.s_diskgid = sbi->s_diskgid;

/*
* Allow the "check" option to be passed as a remount option.
@@ -1342,6 +1431,10 @@ restore_opts:
sbi->s_mount_opt = old_opts.s_mount_opt;
sbi->s_resuid = old_opts.s_resuid;
sbi->s_resgid = old_opts.s_resgid;
+ sbi->s_uid = old_opts.s_uid;
+ sbi->s_diskuid = old_opts.s_diskuid;
+ sbi->s_gid = old_opts.s_gid;
+ sbi->s_diskgid = old_opts.s_diskgid;
sb->s_flags = old_sb_flags;
spin_unlock(&sbi->s_lock);
return err;
--
1.7.10.4
--
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