netlink: make sure nladdr has correct size in netlink_connect()

[pandora-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 7657be4..466d6ee 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -137,7 +137,7 @@ static int do_getname(const char __user *filename, char *page)
        return retval;
 }
 
-static char *getname_flags(const char __user * filename, int flags)
+static char *getname_flags(const char __user *filename, int flags, int *empty)
 {
        char *tmp, *result;
 
@@ -148,6 +148,8 @@ static char *getname_flags(const char __user * filename, int flags)
 
                result = tmp;
                if (retval < 0) {
+                       if (retval == -ENOENT && empty)
+                               *empty = 1;
                        if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) {
                                __putname(tmp);
                                result = ERR_PTR(retval);
@@ -160,7 +162,7 @@ static char *getname_flags(const char __user * filename, int flags)
 
 char *getname(const char __user * filename)
 {
-       return getname_flags(filename, 0);
+       return getname_flags(filename, 0, 0);
 }
 
 #ifdef CONFIG_AUDITSYSCALL
@@ -396,6 +398,25 @@ void path_put(struct path *path)
 }
 EXPORT_SYMBOL(path_put);
 
+/**
+ * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
+ * @path: nameidate to verify
+ *
+ * Rename can sometimes move a file or directory outside of a bind
+ * mount, path_connected allows those cases to be detected.
+ */
+static bool path_connected(const struct path *path)
+{
+       struct vfsmount *mnt = path->mnt;
+       struct super_block *sb = mnt->mnt_sb;
+
+       /* Bind mounts and multi-root filesystems can have disconnected paths */
+       if (!(sb->s_iflags & SB_I_MULTIROOT) && (mnt->mnt_root == sb->s_root))
+               return true;
+
+       return is_subdir(path->dentry, mnt->mnt_root);
+}
+
 /*
  * Path walking has 2 modes, rcu-walk and ref-walk (see
  * Documentation/filesystems/path-lookup.txt).  In situations when we can't
@@ -552,24 +573,22 @@ static int complete_walk(struct nameidata *nd)
 
 static __always_inline void set_root(struct nameidata *nd)
 {
-       if (!nd->root.mnt)
-               get_fs_root(current->fs, &nd->root);
+       get_fs_root(current->fs, &nd->root);
 }
 
 static int link_path_walk(const char *, struct nameidata *);
 
-static __always_inline void set_root_rcu(struct nameidata *nd)
+static __always_inline unsigned set_root_rcu(struct nameidata *nd)
 {
-       if (!nd->root.mnt) {
-               struct fs_struct *fs = current->fs;
-               unsigned seq;
+       struct fs_struct *fs = current->fs;
+       unsigned seq, res;
 
-               do {
-                       seq = read_seqcount_begin(&fs->seq);
-                       nd->root = fs->root;
-                       nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
-               } while (read_seqcount_retry(&fs->seq, seq));
-       }
+       do {
+               seq = read_seqcount_begin(&fs->seq);
+               nd->root = fs->root;
+               res = __read_seqcount_begin(&nd->root.dentry->d_seq);
+       } while (read_seqcount_retry(&fs->seq, seq));
+       return res;
 }
 
 static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
@@ -580,7 +599,8 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
                goto fail;
 
        if (*link == '/') {
-               set_root(nd);
+               if (!nd->root.mnt)
+                       set_root(nd);
                path_put(&nd->path);
                nd->path = nd->root;
                path_get(&nd->root);
@@ -850,7 +870,7 @@ static int follow_managed(struct path *path, unsigned flags)
                mntput(path->mnt);
        if (ret == -EISDIR)
                ret = 0;
-       return ret;
+       return ret < 0 ? ret : need_mntput;
 }
 
 int follow_down_one(struct path *path)
@@ -898,6 +918,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
                        break;
                path->mnt = mounted;
                path->dentry = mounted->mnt_root;
+               nd->flags |= LOOKUP_JUMPED;
                nd->seq = read_seqcount_begin(&path->dentry->d_seq);
                /*
                 * Update the inode too. We don't need to re-check the
@@ -909,22 +930,11 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
        return true;
 }
 
-static void follow_mount_rcu(struct nameidata *nd)
-{
-       while (d_mountpoint(nd->path.dentry)) {
-               struct vfsmount *mounted;
-               mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
-               if (!mounted)
-                       break;
-               nd->path.mnt = mounted;
-               nd->path.dentry = mounted->mnt_root;
-               nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
-       }
-}
-
 static int follow_dotdot_rcu(struct nameidata *nd)
 {
-       set_root_rcu(nd);
+       struct inode *inode = nd->inode;
+       if (!nd->root.mnt)
+               set_root_rcu(nd);
 
        while (1) {
                if (nd->path.dentry == nd->root.dentry &&
@@ -936,19 +946,32 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                        struct dentry *parent = old->d_parent;
                        unsigned seq;
 
+                       inode = parent->d_inode;
                        seq = read_seqcount_begin(&parent->d_seq);
                        if (read_seqcount_retry(&old->d_seq, nd->seq))
                                goto failed;
                        nd->path.dentry = parent;
                        nd->seq = seq;
+                       if (unlikely(!path_connected(&nd->path)))
+                               goto failed;
                        break;
                }
                if (!follow_up_rcu(&nd->path))
                        break;
+               inode = nd->path.dentry->d_inode;
                nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
        }
-       follow_mount_rcu(nd);
-       nd->inode = nd->path.dentry->d_inode;
+       while (d_mountpoint(nd->path.dentry)) {
+               struct vfsmount *mounted;
+               mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
+               if (!mounted)
+                       break;
+               nd->path.mnt = mounted;
+               nd->path.dentry = mounted->mnt_root;
+               inode = nd->path.dentry->d_inode;
+               nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
+       }
+       nd->inode = inode;
        return 0;
 
 failed:
@@ -1025,9 +1048,10 @@ static void follow_mount(struct path *path)
        }
 }
 
-static void follow_dotdot(struct nameidata *nd)
+static int follow_dotdot(struct nameidata *nd)
 {
-       set_root(nd);
+       if (!nd->root.mnt)
+               set_root(nd);
 
        while(1) {
                struct dentry *old = nd->path.dentry;
@@ -1040,6 +1064,10 @@ static void follow_dotdot(struct nameidata *nd)
                        /* rare case of legitimate dget_parent()... */
                        nd->path.dentry = dget_parent(nd->path.dentry);
                        dput(old);
+                       if (unlikely(!path_connected(&nd->path))) {
+                               path_put(&nd->path);
+                               return -ENOENT;
+                       }
                        break;
                }
                if (!follow_up(&nd->path))
@@ -1047,6 +1075,7 @@ static void follow_dotdot(struct nameidata *nd)
        }
        follow_mount(&nd->path);
        nd->inode = nd->path.dentry->d_inode;
+       return 0;
 }
 
 /*
@@ -1091,8 +1120,10 @@ static struct dentry *d_inode_lookup(struct dentry *parent, struct dentry *dentr
        struct dentry *old;
 
        /* Don't create child dentry for a dead directory. */
-       if (unlikely(IS_DEADDIR(inode)))
+       if (unlikely(IS_DEADDIR(inode))) {
+               dput(dentry);
                return ERR_PTR(-ENOENT);
+       }
 
        old = inode->i_op->lookup(inode, dentry, nd);
        if (unlikely(old)) {
@@ -1211,6 +1242,8 @@ retry:
                path_put_conditional(path, nd);
                return err;
        }
+       if (err)
+               nd->flags |= LOOKUP_JUMPED;
        *inode = path->dentry->d_inode;
        return 0;
 }
@@ -1234,7 +1267,7 @@ static inline int handle_dots(struct nameidata *nd, int type)
                        if (follow_dotdot_rcu(nd))
                                return -ECHILD;
                } else
-                       follow_dotdot(nd);
+                       return follow_dotdot(nd);
        }
        return 0;
 }
@@ -1497,7 +1530,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                if (flags & LOOKUP_RCU) {
                        br_read_lock(vfsmount_lock);
                        rcu_read_lock();
-                       set_root_rcu(nd);
+                       nd->seq = set_root_rcu(nd);
                } else {
                        set_root(nd);
                        path_get(&nd->root);
@@ -1553,7 +1586,15 @@ static int path_init(int dfd, const char *name, unsigned int flags,
        }
 
        nd->inode = nd->path.dentry->d_inode;
-       return 0;
+       if (!(flags & LOOKUP_RCU))
+               return 0;
+       if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
+               return 0;
+       if (!(nd->flags & LOOKUP_ROOT))
+               nd->root.mnt = NULL;
+       rcu_read_unlock();
+       br_read_unlock(vfsmount_lock);
+       return -ECHILD;
 
 fput_fail:
        fput_light(file, fput_needed);
@@ -1798,11 +1839,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
        return __lookup_hash(&this, base, NULL);
 }
 
-int user_path_at(int dfd, const char __user *name, unsigned flags,
-                struct path *path)
+int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
+                struct path *path, int *empty)
 {
        struct nameidata nd;
-       char *tmp = getname_flags(name, flags);
+       char *tmp = getname_flags(name, flags, empty);
        int err = PTR_ERR(tmp);
        if (!IS_ERR(tmp)) {
 
@@ -1816,6 +1857,12 @@ int user_path_at(int dfd, const char __user *name, unsigned flags,
        return err;
 }
 
+int user_path_at(int dfd, const char __user *name, unsigned flags,
+                struct path *path)
+{
+       return user_path_at_empty(dfd, name, flags, path, 0);
+}
+
 static int user_path_parent(int dfd, const char __user *path,
                        struct nameidata *nd, char **name)
 {
@@ -2126,7 +2173,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
                /* sayonara */
                error = complete_walk(nd);
                if (error)
-                       return ERR_PTR(-ECHILD);
+                       return ERR_PTR(error);
 
                error = -ENOTDIR;
                if (nd->flags & LOOKUP_DIRECTORY) {
@@ -2138,6 +2185,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        }
 
        /* create side of things */
+       /*
+        * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been
+        * cleared when we got to the last component we are about to look up
+        */
        error = complete_walk(nd);
        if (error)
                return ERR_PTR(error);
@@ -2206,6 +2257,9 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        if (error < 0)
                goto exit_dput;
 
+       if (error)
+               nd->flags |= LOOKUP_JUMPED;
+
        error = -ENOENT;
        if (!path->dentry->d_inode)
                goto exit_dput;
@@ -2215,6 +2269,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 
        path_to_nameidata(path, nd);
        nd->inode = path->dentry->d_inode;
+       /* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
+       error = complete_walk(nd);
+       if (error)
+               return ERR_PTR(error);
        error = -EISDIR;
        if (S_ISDIR(nd->inode->i_mode))
                goto exit;