[PATCH 41/43] userns: Convert tmpfs to use kuid and kgid where appropriate

"Eric W. Beiderman
2012-04-08T05:13:32Z

From: Eric W. Biederman <ebiederm@xmission.com>

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
include/linux/shmem_fs.h | 4 ++--
mm/shmem.c | 22 ++++++++++++++++------
2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 79ab255..bef2cf0 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -28,8 +28,8 @@ struct shmem_sb_info {
unsigned long max_inodes; /* How many inodes are allowed */
unsigned long free_inodes; /* How many are left for allocation */
spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
- uid_t uid; /* Mount uid for root directory */
- gid_t gid; /* Mount gid for root directory */
+ kuid_t uid; /* Mount uid for root directory */
+ kgid_t gid; /* Mount gid for root directory */
umode_t mode; /* Mount mode for root directory */
struct mempolicy *mpol; /* default memory policy for mappings */
};
diff --git a/mm/shmem.c b/mm/shmem.c
index f99ff3e..d7b433a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2075,6 +2075,8 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
bool remount)
{
char *this_char, *value, *rest;
+ uid_t uid;
+ gid_t gid;

while (options != NULL) {
this_char = options;
@@ -2134,15 +2136,21 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
} else if (!strcmp(this_char,"uid")) {
if (remount)
continue;
- sbinfo->uid = simple_strtoul(value, &rest, 0);
+ uid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
+ sbinfo->uid = make_kuid(current_user_ns(), uid);
+ if (!uid_valid(sbinfo->uid))
+ goto bad_val;
} else if (!strcmp(this_char,"gid")) {
if (remount)
continue;
- sbinfo->gid = simple_strtoul(value, &rest, 0);
+ gid = simple_strtoul(value, &rest, 0);
if (*rest)
goto bad_val;
+ sbinfo->gid = make_kgid(current_user_ns(), gid);
+ if (!gid_valid(sbinfo->gid))
+ goto bad_val;
} else if (!strcmp(this_char,"mpol")) {
if (mpol_parse_str(value, &sbinfo->mpol, 1))
goto bad_val;
@@ -2210,10 +2218,12 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root)
seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
seq_printf(seq, ",mode=%03ho", sbinfo->mode);
- if (sbinfo->uid != 0)
- seq_printf(seq, ",uid=%u", sbinfo->uid);
- if (sbinfo->gid != 0)
- seq_printf(seq, ",gid=%u", sbinfo->gid);
+ if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
+ seq_printf(seq, ",uid=%u",
+ from_kuid_munged(&init_user_ns, sbinfo->uid));
+ if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
+ seq_printf(seq, ",gid=%u",
+ from_kgid_munged(&init_user_ns, sbinfo->gid));
shmem_show_mpol(seq, sbinfo->mpol);
return 0;
}
--
1.7.2.5