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    Subject[TOMOYO #16 01/25] LSM: Add security_path_chmod() and security_path_chown().
    This patch allows pathname based LSM modules to check chmod()/chown()
    operations. Since notify_change() does not receive "struct vfsmount *",
    we add security_path_chmod() and security_path_chown() to the caller of
    notify_change().

    These hooks are used by TOMOYO.

    Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
    ---
    fs/open.c | 24 ++++++++++++++++++++----
    include/linux/security.h | 30 ++++++++++++++++++++++++++++++
    security/capability.c | 13 +++++++++++++
    security/security.c | 15 +++++++++++++++
    4 files changed, 78 insertions(+), 4 deletions(-)

    --- security-testing-2.6.orig/fs/open.c
    +++ security-testing-2.6/fs/open.c
    @@ -616,6 +616,9 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd
    err = mnt_want_write_file(file);
    if (err)
    goto out_putf;
    + err = security_path_chmod(dentry, file->f_vfsmnt, mode);
    + if (err)
    + goto out_drop_write;
    mutex_lock(&inode->i_mutex);
    if (mode == (mode_t) -1)
    mode = inode->i_mode;
    @@ -623,6 +626,7 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd
    newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
    err = notify_change(dentry, &newattrs);
    mutex_unlock(&inode->i_mutex);
    +out_drop_write:
    mnt_drop_write(file->f_path.mnt);
    out_putf:
    fput(file);
    @@ -645,6 +649,9 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, cons
    error = mnt_want_write(path.mnt);
    if (error)
    goto dput_and_out;
    + error = security_path_chmod(path.dentry, path.mnt, mode);
    + if (error)
    + goto out_drop_write;
    mutex_lock(&inode->i_mutex);
    if (mode == (mode_t) -1)
    mode = inode->i_mode;
    @@ -652,6 +659,7 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, cons
    newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
    error = notify_change(path.dentry, &newattrs);
    mutex_unlock(&inode->i_mutex);
    +out_drop_write:
    mnt_drop_write(path.mnt);
    dput_and_out:
    path_put(&path);
    @@ -700,7 +708,9 @@ SYSCALL_DEFINE3(chown, const char __user
    error = mnt_want_write(path.mnt);
    if (error)
    goto out_release;
    - error = chown_common(path.dentry, user, group);
    + error = security_path_chown(&path, user, group);
    + if (!error)
    + error = chown_common(path.dentry, user, group);
    mnt_drop_write(path.mnt);
    out_release:
    path_put(&path);
    @@ -725,7 +735,9 @@ SYSCALL_DEFINE5(fchownat, int, dfd, cons
    error = mnt_want_write(path.mnt);
    if (error)
    goto out_release;
    - error = chown_common(path.dentry, user, group);
    + error = security_path_chown(&path, user, group);
    + if (!error)
    + error = chown_common(path.dentry, user, group);
    mnt_drop_write(path.mnt);
    out_release:
    path_put(&path);
    @@ -744,7 +756,9 @@ SYSCALL_DEFINE3(lchown, const char __use
    error = mnt_want_write(path.mnt);
    if (error)
    goto out_release;
    - error = chown_common(path.dentry, user, group);
    + error = security_path_chown(&path, user, group);
    + if (!error)
    + error = chown_common(path.dentry, user, group);
    mnt_drop_write(path.mnt);
    out_release:
    path_put(&path);
    @@ -767,7 +781,9 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd
    goto out_fput;
    dentry = file->f_path.dentry;
    audit_inode(NULL, dentry);
    - error = chown_common(dentry, user, group);
    + error = security_path_chown(&file->f_path, user, group);
    + if (!error)
    + error = chown_common(dentry, user, group);
    mnt_drop_write(file->f_path.mnt);
    out_fput:
    fput(file);
    --- security-testing-2.6.orig/include/linux/security.h
    +++ security-testing-2.6/include/linux/security.h
    @@ -447,6 +447,18 @@ static inline void security_free_mnt_opt
    * @new_dir contains the path structure for parent of the new link.
    * @new_dentry contains the dentry structure of the new link.
    * Return 0 if permission is granted.
    + * @path_chmod:
    + * Check for permission to change DAC's permission of a file or directory.
    + * @dentry contains the dentry structure.
    + * @mnt contains the vfsmnt structure.
    + * @mode contains DAC's mode.
    + * Return 0 if permission is granted.
    + * @path_chown:
    + * Check for permission to change owner/group of a file or directory.
    + * @path contains the path structure.
    + * @uid contains new owner's ID.
    + * @gid contains new group's ID.
    + * Return 0 if permission is granted.
    * @inode_readlink:
    * Check the permission to read the symbolic link.
    * @dentry contains the dentry structure for the file link.
    @@ -1488,6 +1500,9 @@ struct security_operations {
    struct dentry *new_dentry);
    int (*path_rename) (struct path *old_dir, struct dentry *old_dentry,
    struct path *new_dir, struct dentry *new_dentry);
    + int (*path_chmod) (struct dentry *dentry, struct vfsmount *mnt,
    + mode_t mode);
    + int (*path_chown) (struct path *path, uid_t uid, gid_t gid);
    #endif

    int (*inode_alloc_security) (struct inode *inode);
    @@ -2952,6 +2967,9 @@ int security_path_link(struct dentry *ol
    struct dentry *new_dentry);
    int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
    struct path *new_dir, struct dentry *new_dentry);
    +int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
    + mode_t mode);
    +int security_path_chown(struct path *path, uid_t uid, gid_t gid);
    #else /* CONFIG_SECURITY_PATH */
    static inline int security_path_unlink(struct path *dir, struct dentry *dentry)
    {
    @@ -3001,6 +3019,18 @@ static inline int security_path_rename(s
    {
    return 0;
    }
    +
    +static inline int security_path_chmod(struct dentry *dentry,
    + struct vfsmount *mnt,
    + mode_t mode)
    +{
    + return 0;
    +}
    +
    +static inline int security_path_chown(struct path *path, uid_t uid, gid_t gid)
    +{
    + return 0;
    +}
    #endif /* CONFIG_SECURITY_PATH */

    #ifdef CONFIG_KEYS
    --- security-testing-2.6.orig/security/capability.c
    +++ security-testing-2.6/security/capability.c
    @@ -308,6 +308,17 @@ static int cap_path_truncate(struct path
    {
    return 0;
    }
    +
    +static int cap_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
    + mode_t mode)
    +{
    + return 0;
    +}
    +
    +static int cap_path_chown(struct path *path, uid_t uid, gid_t gid)
    +{
    + return 0;
    +}
    #endif

    static int cap_file_permission(struct file *file, int mask)
    @@ -977,6 +988,8 @@ void security_fixup_ops(struct security_
    set_to_cap_if_null(ops, path_link);
    set_to_cap_if_null(ops, path_rename);
    set_to_cap_if_null(ops, path_truncate);
    + set_to_cap_if_null(ops, path_chmod);
    + set_to_cap_if_null(ops, path_chown);
    #endif
    set_to_cap_if_null(ops, file_permission);
    set_to_cap_if_null(ops, file_alloc_security);
    --- security-testing-2.6.orig/security/security.c
    +++ security-testing-2.6/security/security.c
    @@ -434,6 +434,21 @@ int security_path_truncate(struct path *
    return 0;
    return security_ops->path_truncate(path, length, time_attrs);
    }
    +
    +int security_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
    + mode_t mode)
    +{
    + if (unlikely(IS_PRIVATE(dentry->d_inode)))
    + return 0;
    + return security_ops->path_chmod(dentry, mnt, mode);
    +}
    +
    +int security_path_chown(struct path *path, uid_t uid, gid_t gid)
    +{
    + if (unlikely(IS_PRIVATE(path->dentry->d_inode)))
    + return 0;
    + return security_ops->path_chown(path, uid, gid);
    +}
    #endif

    int security_inode_create(struct inode *dir, struct dentry *dentry, int mode)
    --


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