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Date: Wed, 11 Apr 2012 20:08:23 -0400
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: Subodh Nijsure <subodh.nijsure@...il.com>
Cc: linux-mtd@...ts.infradead.org,
Artem Bityutskiy <dedekind1@...il.com>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org,
Subodh Nijsure <snijsure@...d-net.com>
Subject: Re: [PATCH v3] Add security.* XATTR support for the UBIFS
On Wed, 2012-04-11 at 16:45 -0700, Subodh Nijsure wrote:
> On Wed, Apr 11, 2012 at 4:27 PM, Mimi Zohar <zohar@...ux.vnet.ibm.com> wrote:
> > On Wed, 2012-04-11 at 14:28 -0700, subodh.nijsure@...il.com wrote:
> >> From: Subodh Nijsure <snijsure@...d-net.com>
> >>
> >> Also fix couple of bugs in UBIFS extended attribute length calculation.
> >>
> >> Changes in v3:
> >> Invoke ubifs_init_security only if CONFIG_UBIFS_FS_XATTR is defined.
> >> Invoke it before d_instantiate and check ubifs_init_security return
> >> code.
> >
> >> Changes in v2:
> >> Instead of just handling security.selinux extended attribute handle
> >> all security.* attributes.
> >>
> >> TESTING: Tested on 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.
> >> This change also allows one to set other security.* extended
> >> attributes, such as security.smack security.evm, security.ima
> >> Ran integck test on UBI filesystem.
> >>
> >> Signed-off-by: Subodh Nijsure <snijsure@...d-net.com>
> >> ---
> >> fs/ubifs/dir.c | 47 +++++++++++++++++
> >> fs/ubifs/file.c | 6 ++
> >> fs/ubifs/journal.c | 12 +++-
> >> fs/ubifs/super.c | 3 +
> >> fs/ubifs/ubifs.h | 9 +++
> >> fs/ubifs/xattr.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++----
> >> 6 files changed, 210 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
> >> index ec9f187..422bcec 100644
> >> --- a/fs/ubifs/dir.c
> >> +++ b/fs/ubifs/dir.c
> >> @@ -292,6 +292,18 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
> >>
> >> ubifs_release_budget(c, &req);
> >> insert_inode_hash(inode);
> >> +
> >> +#ifdef CONFIG_UBIFS_FS_XATTR
> >> +
> >> + err = ubifs_init_security(dir, inode, &dentry->d_name);
> >> + if (err) {
> >> + ubifs_err("cannot initialize extended attribute, error %d",
> >> + err);
> >> + goto out_cancel;
> >> + }
> >> +
> >> +#endif
> >> +
> >
> > The preferred method for including code based on CONFIG options is to
> > define a stub function in an include file. #ifdef's in C code is
> > frowned upon (refer to section 2.2 of Documentation/SubmittingPatches).
> >
> > thanks,
> >
> > Mimi
>
> I can certainly change the code to follow that guideline, sorry I missed it...
>
> There is other code in ubifs that uses #ifdef
> CONFIG_UBIFS_FS_XATTR/#endif should I be changing that or expectation
> is not to introduce new #ifdef/#endif? And if its the prior should
> that change come in as separate patch set?
>
> BTW, would very much appreciate if someone can actually test this
> patch with UBIFS on their hardware. I have posted a patch to
> mtd-utils/integck test program on linux-mtd mailing list.
>
> Regards,
> -Subodh
Definitely keep your patch separate from any other cleanup. Most, if
not all other filesystems, put the xattr code in a separate file. The
Makefile includes the file based on the CONFIG option. Refer to
fs/ext3|ext4/Makefile for an example.
thanks,
Mimi
> >> d_instantiate(dentry, inode);
> >> return 0;
> >>
> >> @@ -753,6 +765,17 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
> >> mutex_unlock(&dir_ui->ui_mutex);
> >>
> >> ubifs_release_budget(c, &req);
> >> +
> >> +#ifdef CONFIG_UBIFS_FS_XATTR
> >> +
> >> + err = ubifs_init_security(dir, inode, &dentry->d_name);
> >> + if (err) {
> >> + ubifs_err("cannot initialize extended attribute, error %d",
> >> + err);
> >> + goto out_cancel;
> >> + }
> >> +
> >> +#endif
> >> d_instantiate(dentry, inode);
> >> return 0;
> >>
> >> @@ -830,6 +853,18 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
> >>
> >> ubifs_release_budget(c, &req);
> >> insert_inode_hash(inode);
> >> +
> >> +#ifdef CONFIG_UBIFS_FS_XATTR
> >> +
> >> + err = ubifs_init_security(dir, inode, &dentry->d_name);
> >> + if (err) {
> >> + ubifs_err("cannot initialize extended attribute, error %d",
> >> + err);
> >> + goto out_cancel;
> >> + }
> >> +
> >> +#endif
> >> +
> >> d_instantiate(dentry, inode);
> >> return 0;
> >>
> >> @@ -906,6 +941,18 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
> >>
> >> ubifs_release_budget(c, &req);
> >> insert_inode_hash(inode);
> >> +
> >> +#ifdef CONFIG_UBIFS_FS_XATTR
> >> +
> >> + err = ubifs_init_security(dir, inode, &dentry->d_name);
> >> + if (err) {
> >> + ubifs_err("cannot initialize extended attribute, error %d",
> >> + err);
> >> + goto out_cancel;
> >> + }
> >> +
> >> +#endif
> >> +
> >> d_instantiate(dentry, inode);
> >> return 0;
> >>
> >> diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
> >> index 5c8f6dc..b8e9d66 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 2f438ab..725dc17 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;
> >> @@ -649,7 +654,8 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
> >>
> >> ino_key_init(c, &ino_key, dir->i_ino);
> >> ino_offs += aligned_ilen;
> >> - err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, UBIFS_INO_NODE_SZ);
> >> + err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs,
> >> + UBIFS_INO_NODE_SZ + dir_ui->data_len);
> >> if (err)
> >> goto out_ro;
> >>
> >> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> >> index 76e4e05..c28ac04 100644
> >> --- a/fs/ubifs/super.c
> >> +++ b/fs/ubifs/super.c
> >> @@ -2061,6 +2061,9 @@ 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;
> >> +#ifdef CONFIG_UBIFS_FS_XATTR
> >> + sb->s_xattr = ubifs_xattr_handlers;
> >> +#endif
> >>
> >> mutex_lock(&c->umount_mutex);
> >> err = mount_ubifs(c);
> >> diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
> >> index 93d59ac..60b57f7 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 */
> >> @@ -1454,6 +1455,7 @@ 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;
> >> @@ -1736,10 +1738,17 @@ int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
> >> struct kstat *stat);
> >>
> >> /* xattr.c */
> >> +
> >> int ubifs_setxattr(struct dentry *dentry, const char *name,
> >> const void *value, size_t size, int flags);
> >> +int ubifs_init_security(struct inode *dentry, struct inode *inode,
> >> + const struct qstr *qstr);
> >> +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 85b2722..c8be7cd 100644
> >> --- a/fs/ubifs/xattr.c
> >> +++ b/fs/ubifs/xattr.c
> >> @@ -209,11 +209,11 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
> >> goto out_free;
> >> }
> >> 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);
> >>
> >> /*
> >> @@ -293,18 +293,16 @@ 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,
> >> - const void *value, size_t size, int flags)
> >> +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)
> >> @@ -356,10 +354,29 @@ out_free:
> >> return err;
> >> }
> >>
> >> -ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
> >> - size_t size)
> >> +int ubifs_symlink_setxattr(struct dentry *dentry, const char *name,
> >> + const void *value, size_t size, int flags)
> >> {
> >> - struct inode *inode, *host = dentry->d_inode;
> >> + 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;
> >> struct ubifs_info *c = host->i_sb->s_fs_info;
> >> struct qstr nm = { .name = name, .len = strlen(name) };
> >> struct ubifs_inode *ui;
> >> @@ -367,8 +384,8 @@ 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);
> >> + dbg_gen("xattr '%s', ino %lu buf size %zd", name,
> >> + host->i_ino, size);
> >>
> >> err = check_namespace(&nm);
> >> if (err < 0)
> >> @@ -416,6 +433,25 @@ 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;
> >> @@ -568,3 +604,92 @@ 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, name, 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, name, 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
> >> +};
> >> +
> >> +static int ubifs_initxattrs(struct inode *inode,
> >> + const struct xattr *xattr_array, void *fs_info)
> >> +{
> >> + const struct xattr *xattr;
> >> + char *name;
> >> + int err = 0;
> >> +
> >> + for (xattr = xattr_array; xattr->name != NULL; xattr++) {
> >> + name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
> >> + strlen(xattr->name) + 1, GFP_NOFS);
> >> + if (!name) {
> >> + err = -ENOMEM;
> >> + break;
> >> + }
> >> + strcpy(name, XATTR_SECURITY_PREFIX);
> >> + strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
> >> +
> >> + err = __ubifs_setxattr(inode, xattr->name, xattr->value,
> >> + xattr->value_len, 0);
> >> + kfree(name);
> >> + if (err < 0)
> >> + break;
> >> + }
> >> + return err;
> >> +}
> >> +
> >> +int
> >> +ubifs_init_security(struct inode *dentry, struct inode *inode,
> >> + const struct qstr *qstr)
> >> +{
> >> + struct ubifs_inode *dir_ui = ubifs_inode(inode);
> >> + int err = 0;
> >> +
> >> + mutex_lock(&dir_ui->ui_mutex);
> >> + mutex_lock(&inode->i_mutex);
> >> +
> >> + err = security_inode_init_security(inode, dentry, qstr,
> >> + &ubifs_initxattrs, 0);
> >> + mutex_unlock(&inode->i_mutex);
> >> + mutex_unlock(&dir_ui->ui_mutex);
> >> + return err;
> >> +}
> >
> >
>
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