introduce new LSM hooks where vfsmount is available.

Add new LSM hooks for path-based checks.  Call them on directory-modifying
operations at the points where we still know the vfsmount involved.

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 36 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index af3783fff1de..ab441af4196b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1556,6 +1556,9 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
                  * Refuse to truncate files with mandatory locks held on them.
                  */
                 error = locks_verify_locked(inode);
+                if (!error)
+                        error = security_path_truncate(&nd->path, 0,
+                                               ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
                 if (!error) {
                         DQUOT_INIT(inode);
 
@@ -1586,7 +1589,11 @@ static int __open_namei_create(struct nameidata *nd, struct path *path,
 
         if (!IS_POSIXACL(dir->d_inode))
                 mode &= ~current->fs->umask;
+        error = security_path_mknod(&nd->path, path->dentry, mode, 0);
+        if (error)
+                goto out_unlock;
         error = vfs_create(dir->d_inode, path->dentry, mode, nd);
+out_unlock:
         mutex_unlock(&dir->d_inode->i_mutex);
         dput(nd->path.dentry);
         nd->path.dentry = path->dentry;
@@ -1999,6 +2006,9 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto out_dput;
+        error = security_path_mknod(&nd.path, dentry, mode, dev);
+        if (error)
+                goto out_drop_write;
         switch (mode & S_IFMT) {
                 case 0: case S_IFREG:
                         error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
@@ -2011,6 +2021,7 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
                         error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
                         break;
         }
+out_drop_write:
         mnt_drop_write(nd.path.mnt);
 out_dput:
         dput(dentry);
@@ -2070,7 +2081,11 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto out_dput;
+        error = security_path_mkdir(&nd.path, dentry, mode);
+        if (error)
+                goto out_drop_write;
         error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
+out_drop_write:
         mnt_drop_write(nd.path.mnt);
 out_dput:
         dput(dentry);
@@ -2180,7 +2195,11 @@ static long do_rmdir(int dfd, const char __user *pathname)
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto exit3;
+        error = security_path_rmdir(&nd.path, dentry);
+        if (error)
+                goto exit4;
         error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
+exit4:
         mnt_drop_write(nd.path.mnt);
 exit3:
         dput(dentry);
@@ -2265,7 +2284,11 @@ static long do_unlinkat(int dfd, const char __user *pathname)
                 error = mnt_want_write(nd.path.mnt);
                 if (error)
                         goto exit2;
+                error = security_path_unlink(&nd.path, dentry);
+                if (error)
+                        goto exit3;
                 error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+exit3:
                 mnt_drop_write(nd.path.mnt);
         exit2:
                 dput(dentry);
@@ -2346,7 +2369,11 @@ asmlinkage long sys_symlinkat(const char __user *oldname,
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto out_dput;
+        error = security_path_symlink(&nd.path, dentry, from);
+        if (error)
+                goto out_drop_write;
         error = vfs_symlink(nd.path.dentry->d_inode, dentry, from);
+out_drop_write:
         mnt_drop_write(nd.path.mnt);
 out_dput:
         dput(dentry);
@@ -2443,7 +2470,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
         error = mnt_want_write(nd.path.mnt);
         if (error)
                 goto out_dput;
+        error = security_path_link(old_path.dentry, &nd.path, new_dentry);
+        if (error)
+                goto out_drop_write;
         error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
+out_drop_write:
         mnt_drop_write(nd.path.mnt);
 out_dput:
         dput(new_dentry);
@@ -2679,8 +2710,13 @@ asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
         error = mnt_want_write(oldnd.path.mnt);
         if (error)
                 goto exit5;
+        error = security_path_rename(&oldnd.path, old_dentry,
+                                     &newnd.path, new_dentry);
+        if (error)
+                goto exit6;
         error = vfs_rename(old_dir->d_inode, old_dentry,
                                    new_dir->d_inode, new_dentry);
+exit6:
         mnt_drop_write(oldnd.path.mnt);
 exit5:
         dput(new_dentry);