[PATCH 1/1] Add security.selinux XATTR support for the UBIFS. Also fix couple of bugs in UBIFS extended attribute storage.
Subodh Nijsure
subodh.nijsure at gmail.com
Tue Oct 11 14:52:22 EDT 2011
From: Subodh Nijsure <snijsure at grid-net.com>
TESTING: Tested on MX25, MX28 based platforms using Micron MT29F2G08ABAEAH4 NAND
With these change we are able to label UBIFS filesystem with security.selinux
and run system with selinux enabled.
Signed-off-by: Subodh Nijsure <snijsure at grid-net.com>
---
fs/ubifs/dir.c | 50 +++++++++++++++++++++++++++
fs/ubifs/file.c | 6 +++
fs/ubifs/journal.c | 11 ++++--
fs/ubifs/super.c | 1 +
fs/ubifs/ubifs.h | 6 +++
fs/ubifs/xattr.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++-----
6 files changed, 158 insertions(+), 13 deletions(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 6834920..ef98495 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -253,6 +253,52 @@ out:
return ERR_PTR(err);
}
+static void ubifs_init_security(struct dentry *dentry, struct inode *inode,
+ struct inode *dir)
+{
+ int err;
+ char *name;
+ void *value = NULL;
+ size_t len = 0;
+ struct ubifs_inode *dir_ui = ubifs_inode(dir);
+ const struct qstr *qname = &dentry->d_name;
+
+ mutex_lock(&dir_ui->ui_mutex);
+ mutex_lock(&dentry->d_inode->i_mutex);
+ err = security_inode_init_security(inode, dir, qname, &name, &value,
+ &len);
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ return;
+ ubifs_err("unable to retrieve security context, error %d", err);
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ mutex_unlock(&dir_ui->ui_mutex);
+ return;
+ }
+
+ if (strncmp(name, "selinux", strlen("selinux")) == 0) {
+ kfree(name);
+ name = kstrdup("security.selinux", GFP_NOFS);
+ if (!name) {
+ ubifs_err("unable to set security context %.*s error",
+ dentry->d_name.len, dentry->d_name.name);
+ kfree(value);
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ mutex_unlock(&dir_ui->ui_mutex);
+ return;
+ }
+ }
+
+ err = ubifs_setxattr(dentry, name, value, len, 0);
+ if (err)
+ ubifs_err("unable to set security context name %.*s error %d",
+ dentry->d_name.len, dentry->d_name.name, err);
+ kfree(name);
+ kfree(value);
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ mutex_unlock(&dir_ui->ui_mutex);
+}
+
static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
struct nameidata *nd)
{
@@ -293,6 +339,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
ubifs_release_budget(c, &req);
insert_inode_hash(inode);
d_instantiate(dentry, inode);
+ ubifs_init_security(dentry, inode, dir);
return 0;
out_cancel:
@@ -754,6 +801,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
ubifs_release_budget(c, &req);
d_instantiate(dentry, inode);
+ ubifs_init_security(dentry, inode, dir);
return 0;
out_cancel:
@@ -831,6 +879,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
ubifs_release_budget(c, &req);
insert_inode_hash(inode);
d_instantiate(dentry, inode);
+ ubifs_init_security(dentry, inode, dir);
return 0;
out_cancel:
@@ -907,6 +956,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
ubifs_release_budget(c, &req);
insert_inode_hash(inode);
d_instantiate(dentry, inode);
+ ubifs_init_security(dentry, inode, dir);
return 0;
out_cancel:
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index f9c234b..ba33491 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1575,6 +1575,12 @@ const struct inode_operations ubifs_symlink_inode_operations = {
.follow_link = ubifs_follow_link,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
+#ifdef CONFIG_UBIFS_FS_XATTR
+ .setxattr = ubifs_symlink_setxattr,
+ .getxattr = ubifs_symlink_getxattr,
+ .listxattr = ubifs_listxattr,
+ .removexattr = ubifs_removexattr,
+#endif
};
const struct file_operations ubifs_file_operations = {
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index cef0460..5e1ebdb 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -553,7 +553,8 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
dbg_jnl("ino %lu, dent '%.*s', data len %d in dir ino %lu",
inode->i_ino, nm->len, nm->name, ui->data_len, dir->i_ino);
- ubifs_assert(dir_ui->data_len == 0);
+ if (!xent)
+ ubifs_assert(dir_ui->data_len == 0);
ubifs_assert(mutex_is_locked(&dir_ui->ui_mutex));
dlen = UBIFS_DENT_NODE_SZ + nm->len + 1;
@@ -572,7 +573,11 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
aligned_dlen = ALIGN(dlen, 8);
aligned_ilen = ALIGN(ilen, 8);
- len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ;
+ /* Make sure to account for dir_ui+data_len in length calculation
+ * in case there is extended attribute.
+ */
+ len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ
+ + dir_ui->data_len;
dent = kmalloc(len, GFP_NOFS);
if (!dent)
return -ENOMEM;
@@ -643,7 +648,7 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
*/
ino_key_init(c, &ino_key, inode->i_ino);
ino_offs = dent_offs + aligned_dlen;
- err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen);
+ err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen+dir_ui->data_len);
if (err)
goto out_ro;
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index b281212..025e5d0 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2062,6 +2062,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
if (c->max_inode_sz > MAX_LFS_FILESIZE)
sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
sb->s_op = &ubifs_super_operations;
+ sb->s_xattr = ubifs_xattr_handlers;
mutex_lock(&c->umount_mutex);
err = mount_ubifs(c);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 27f2255..1e00ec5 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -36,6 +36,7 @@
#include <linux/mtd/ubi.h>
#include <linux/pagemap.h>
#include <linux/backing-dev.h>
+#include <linux/security.h>
#include "ubifs-media.h"
/* Version of this UBIFS implementation */
@@ -1457,6 +1458,7 @@ extern spinlock_t ubifs_infos_lock;
extern atomic_long_t ubifs_clean_zn_cnt;
extern struct kmem_cache *ubifs_inode_slab;
extern const struct super_operations ubifs_super_operations;
+extern const struct xattr_handler *ubifs_xattr_handlers[];
extern const struct address_space_operations ubifs_file_address_operations;
extern const struct file_operations ubifs_file_operations;
extern const struct inode_operations ubifs_file_inode_operations;
@@ -1741,8 +1743,12 @@ int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
/* xattr.c */
int ubifs_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags);
+int ubifs_symlink_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags);
ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
size_t size);
+ssize_t ubifs_symlink_getxattr(struct dentry *dentry, const char *name,
+ void *buf, size_t size);
ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size);
int ubifs_removexattr(struct dentry *dentry, const char *name);
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index 16f19f5..cfacab9 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -211,11 +211,11 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
}
memcpy(ui->data, value, size);
inode->i_size = ui->ui_size = size;
- ui->data_len = size;
mutex_lock(&host_ui->ui_mutex);
host->i_ctime = ubifs_current_time(host);
host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
+ ui->data_len = size;
host_ui->xattr_size += CALC_XATTR_BYTES(size);
/*
@@ -295,18 +295,16 @@ static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
return ERR_PTR(-EINVAL);
}
-int ubifs_setxattr(struct dentry *dentry, const char *name,
+static int __ubifs_setxattr(struct inode *host, const char *name,
const void *value, size_t size, int flags)
{
- struct inode *inode, *host = dentry->d_inode;
+ struct inode *inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = { .name = name, .len = strlen(name) };
struct ubifs_dent_node *xent;
union ubifs_key key;
int err, type;
- dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
- host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
ubifs_assert(mutex_is_locked(&host->i_mutex));
if (size > UBIFS_MAX_INO_DATA)
@@ -358,10 +356,29 @@ out_free:
return err;
}
-ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
+int ubifs_symlink_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct inode *host = dentry->d_inode;
+ dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
+ host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+ return __ubifs_setxattr(host, name, value, size, flags);
+}
+
+int ubifs_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct inode *host = dentry->d_inode;
+ dbg_gen("xattr '%s', host ino %lu ('%.*s'), size %zd", name,
+ host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+ return __ubifs_setxattr(host, name, value, size, flags);
+}
+
+static
+ssize_t __ubifs_getxattr(struct inode *host, const char *name, void *buf,
size_t size)
{
- struct inode *inode, *host = dentry->d_inode;
+ struct inode *inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = { .name = name, .len = strlen(name) };
struct ubifs_inode *ui;
@@ -369,9 +386,6 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
union ubifs_key key;
int err;
- dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
- host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
-
err = check_namespace(&nm);
if (err < 0)
return err;
@@ -418,6 +432,25 @@ out_unlock:
return err;
}
+ssize_t ubifs_symlink_getxattr(struct dentry *dentry, const char *name,
+ void *buf, size_t size)
+{
+ struct inode *host = dentry->d_inode;
+ dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
+ host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+ return __ubifs_getxattr(host, name, buf, size);
+}
+
+ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
+ size_t size)
+{
+ struct inode *host = dentry->d_inode;
+ dbg_gen("xattr '%s', ino %lu ('%.*s'), buf size %zd", name,
+ host->i_ino, dentry->d_name.len, dentry->d_name.name, size);
+ return __ubifs_getxattr(host, name, buf, size);
+}
+
+
ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
union ubifs_key key;
@@ -570,3 +603,47 @@ out_free:
kfree(xent);
return err;
}
+
+size_t
+ubifs_security_listxattr(struct dentry *d, char *list, size_t list_size,
+ const char *name, size_t name_len, int flags)
+{
+ const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
+ const size_t total_len = prefix_len + name_len + 1;
+ if (list && total_len <= list_size) {
+ memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+ memcpy(list+prefix_len, name, name_len);
+ list[prefix_len + name_len] = '\0';
+ }
+ return total_len;
+}
+
+
+int ubifs_security_getxattr(struct dentry *d, const char *name,
+ void *buffer, size_t size, int flags)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return __ubifs_getxattr(d->d_inode, XATTR_NAME_SELINUX, buffer, size);
+}
+
+int ubifs_security_setxattr(struct dentry *d, const char *name,
+ const void *value, size_t size, int flags, int handler_flags)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return __ubifs_setxattr(d->d_inode, XATTR_NAME_SELINUX, value,
+ size, flags);
+}
+
+struct xattr_handler ubifs_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .list = ubifs_security_listxattr,
+ .get = ubifs_security_getxattr,
+ .set = ubifs_security_setxattr,
+};
+
+const struct xattr_handler *ubifs_xattr_handlers[] = {
+ &ubifs_xattr_security_handler,
+ NULL
+};
--
1.7.4.1
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