1 files changed, 97 insertions, 54 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 967c3db92724..f3c5b278895a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -552,6 +552,17 @@ static __always_inline int link_path_walk(const char *name, struct nameidata *nd
         return result;
 }
 
+static __always_inline void set_root(struct nameidata *nd)
+{
+        if (!nd->root.mnt) {
+                struct fs_struct *fs = current->fs;
+                read_lock(&fs->lock);
+                nd->root = fs->root;
+                path_get(&nd->root);
+                read_unlock(&fs->lock);
+        }
+}
+
 static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
 {
         int res = 0;
@@ -560,14 +571,10 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
                 goto fail;
 
         if (*link == '/') {
-                struct fs_struct *fs = current->fs;
-
+                set_root(nd);
                 path_put(&nd->path);
-
-                read_lock(&fs->lock);
-                nd->path = fs->root;
-                path_get(&fs->root);
-                read_unlock(&fs->lock);
+                nd->path = nd->root;
+                path_get(&nd->root);
         }
 
         res = link_path_walk(link, nd);
@@ -668,23 +675,23 @@ loop:
         return err;
 }
 
-int follow_up(struct vfsmount **mnt, struct dentry **dentry)
+int follow_up(struct path *path)
 {
         struct vfsmount *parent;
         struct dentry *mountpoint;
         spin_lock(&vfsmount_lock);
-        parent=(*mnt)->mnt_parent;
-        if (parent == *mnt) {
+        parent = path->mnt->mnt_parent;
+        if (parent == path->mnt) {
                 spin_unlock(&vfsmount_lock);
                 return 0;
         }
         mntget(parent);
-        mountpoint=dget((*mnt)->mnt_mountpoint);
+        mountpoint = dget(path->mnt->mnt_mountpoint);
         spin_unlock(&vfsmount_lock);
-        dput(*dentry);
-        *dentry = mountpoint;
-        mntput(*mnt);
-        *mnt = parent;
+        dput(path->dentry);
+        path->dentry = mountpoint;
+        mntput(path->mnt);
+        path->mnt = parent;
         return 1;
 }
 
@@ -695,7 +702,7 @@ static int __follow_mount(struct path *path)
 {
         int res = 0;
         while (d_mountpoint(path->dentry)) {
-                struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry);
+                struct vfsmount *mounted = lookup_mnt(path);
                 if (!mounted)
                         break;
                 dput(path->dentry);
@@ -708,32 +715,32 @@ static int __follow_mount(struct path *path)
         return res;
 }
 
-static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
+static void follow_mount(struct path *path)
 {
-        while (d_mountpoint(*dentry)) {
-                struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
+        while (d_mountpoint(path->dentry)) {
+                struct vfsmount *mounted = lookup_mnt(path);
                 if (!mounted)
                         break;
-                dput(*dentry);
-                mntput(*mnt);
-                *mnt = mounted;
-                *dentry = dget(mounted->mnt_root);
+                dput(path->dentry);
+                mntput(path->mnt);
+                path->mnt = mounted;
+                path->dentry = dget(mounted->mnt_root);
         }
 }
 
 /* no need for dcache_lock, as serialization is taken care in
  * namespace.c
  */
-int follow_down(struct vfsmount **mnt, struct dentry **dentry)
+int follow_down(struct path *path)
 {
         struct vfsmount *mounted;
 
-        mounted = lookup_mnt(*mnt, *dentry);
+        mounted = lookup_mnt(path);
         if (mounted) {
-                dput(*dentry);
-                mntput(*mnt);
-                *mnt = mounted;
-                *dentry = dget(mounted->mnt_root);
+                dput(path->dentry);
+                mntput(path->mnt);
+                path->mnt = mounted;
+                path->dentry = dget(mounted->mnt_root);
                 return 1;
         }
         return 0;
@@ -741,19 +748,16 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry)
 
 static __always_inline void follow_dotdot(struct nameidata *nd)
 {
-        struct fs_struct *fs = current->fs;
+        set_root(nd);
 
         while(1) {
                 struct vfsmount *parent;
                 struct dentry *old = nd->path.dentry;
 
-                read_lock(&fs->lock);
-                if (nd->path.dentry == fs->root.dentry &&
-                    nd->path.mnt == fs->root.mnt) {
-                        read_unlock(&fs->lock);
+                if (nd->path.dentry == nd->root.dentry &&
+                    nd->path.mnt == nd->root.mnt) {
                         break;
                 }
-                read_unlock(&fs->lock);
                 spin_lock(&dcache_lock);
                 if (nd->path.dentry != nd->path.mnt->mnt_root) {
                         nd->path.dentry = dget(nd->path.dentry->d_parent);
@@ -775,7 +779,7 @@ static __always_inline void follow_dotdot(struct nameidata *nd)
                 mntput(nd->path.mnt);
                 nd->path.mnt = parent;
         }
-        follow_mount(&nd->path.mnt, &nd->path.dentry);
+        follow_mount(&nd->path);
 }
 
 /*
@@ -853,7 +857,8 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
                         err = inode_permission(nd->path.dentry->d_inode,
                                                MAY_EXEC);
                 if (!err)
-                        err = ima_path_check(&nd->path, MAY_EXEC);
+                        err = ima_path_check(&nd->path, MAY_EXEC,
+                                             IMA_COUNT_UPDATE);
                 if (err)
                         break;
 
@@ -1016,25 +1021,23 @@ static int path_walk(const char *name, struct nameidata *nd)
         return link_path_walk(name, nd);
 }
 
-/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int do_path_lookup(int dfd, const char *name,
-                                unsigned int flags, struct nameidata *nd)
+static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
 {
         int retval = 0;
         int fput_needed;
         struct file *file;
-        struct fs_struct *fs = current->fs;
 
         nd->last_type = LAST_ROOT; /* if there are only slashes... */
         nd->flags = flags;
         nd->depth = 0;
+        nd->root.mnt = NULL;
 
         if (*name=='/') {
-                read_lock(&fs->lock);
-                nd->path = fs->root;
-                path_get(&fs->root);
-                read_unlock(&fs->lock);
+                set_root(nd);
+                nd->path = nd->root;
+                path_get(&nd->root);
         } else if (dfd == AT_FDCWD) {
+                struct fs_struct *fs = current->fs;
                 read_lock(&fs->lock);
                 nd->path = fs->pwd;
                 path_get(&fs->pwd);
@@ -1062,17 +1065,29 @@ static int do_path_lookup(int dfd, const char *name,
 
                 fput_light(file, fput_needed);
         }
+        return 0;
 
-        retval = path_walk(name, nd);
+fput_fail:
+        fput_light(file, fput_needed);
+out_fail:
+        return retval;
+}
+
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
+static int do_path_lookup(int dfd, const char *name,
+                                unsigned int flags, struct nameidata *nd)
+{
+        int retval = path_init(dfd, name, flags, nd);
+        if (!retval)
+                retval = path_walk(name, nd);
         if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
                                 nd->path.dentry->d_inode))
                 audit_inode(name, nd->path.dentry);
-out_fail:
+        if (nd->root.mnt) {
+                path_put(&nd->root);
+                nd->root.mnt = NULL;
+        }
         return retval;
-
-fput_fail:
-        fput_light(file, fput_needed);
-        goto out_fail;
 }
 
 int path_lookup(const char *name, unsigned int flags,
@@ -1112,14 +1127,18 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
         nd->path.dentry = dentry;
         nd->path.mnt = mnt;
         path_get(&nd->path);
+        nd->root = nd->path;
+        path_get(&nd->root);
 
         retval = path_walk(name, nd);
         if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
                                 nd->path.dentry->d_inode))
                 audit_inode(name, nd->path.dentry);
 
-        return retval;
+        path_put(&nd->root);
+        nd->root.mnt = NULL;
 
+        return retval;
 }
 
 /**
@@ -1515,7 +1534,8 @@ int may_open(struct path *path, int acc_mode, int flag)
                 return error;
 
         error = ima_path_check(path,
-                               acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
+                               acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC),
+                               IMA_COUNT_UPDATE);
         if (error)
                 return error;
         /*
@@ -1674,9 +1694,17 @@ struct file *do_filp_open(int dfd, const char *pathname,
         /*
          * Create - we need to know the parent.
          */
-        error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
+        error = path_init(dfd, pathname, LOOKUP_PARENT, &nd);
         if (error)
                 return ERR_PTR(error);
+        error = path_walk(pathname, &nd);
+        if (error) {
+                if (nd.root.mnt)
+                        path_put(&nd.root);
+                return ERR_PTR(error);
+        }
+        if (unlikely(!audit_dummy_context()))
+                audit_inode(pathname, nd.path.dentry);
 
         /*
          * We have the parent and last component. First of all, check
@@ -1733,7 +1761,13 @@ do_last:
                         goto exit;
                 }
                 filp = nameidata_to_filp(&nd, open_flag);
+                if (IS_ERR(filp))
+                        ima_counts_put(&nd.path,
+                                       acc_mode & (MAY_READ | MAY_WRITE |
+                                                   MAY_EXEC));
                 mnt_drop_write(nd.path.mnt);
+                if (nd.root.mnt)
+                        path_put(&nd.root);
                 return filp;
         }
 
@@ -1787,6 +1821,9 @@ ok:
                 goto exit;
         }
         filp = nameidata_to_filp(&nd, open_flag);
+        if (IS_ERR(filp))
+                ima_counts_put(&nd.path,
+                               acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
         /*
          * It is now safe to drop the mnt write
          * because the filp has had a write taken
@@ -1794,6 +1831,8 @@ ok:
          */
         if (will_write)
                 mnt_drop_write(nd.path.mnt);
+        if (nd.root.mnt)
+                path_put(&nd.root);
         return filp;
 
 exit_mutex_unlock:
@@ -1804,6 +1843,8 @@ exit:
         if (!IS_ERR(nd.intent.open.file))
                 release_open_intent(&nd);
 exit_parent:
+        if (nd.root.mnt)
+                path_put(&nd.root);
         path_put(&nd.path);
         return ERR_PTR(error);
 
@@ -1832,6 +1873,8 @@ do_link:
                  * with "intent.open".
                  */
                 release_open_intent(&nd);
+                if (nd.root.mnt)
+                        path_put(&nd.root);
                 return ERR_PTR(error);
         }
         nd.flags &= ~LOOKUP_PARENT;