[PATCH v3] Add security.* XATTR support for the UBIFS

Mimi Zohar zohar at linux.vnet.ibm.com
Wed Apr 11 20:08:23 EDT 2012


On Wed, 2012-04-11 at 16:45 -0700, Subodh Nijsure wrote:
> On Wed, Apr 11, 2012 at 4:27 PM, Mimi Zohar <zohar at linux.vnet.ibm.com> wrote:
> > On Wed, 2012-04-11 at 14:28 -0700, subodh.nijsure at gmail.com wrote:
> >> From: Subodh Nijsure <snijsure at grid-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 at grid-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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