1 files changed, 75 insertions, 40 deletions

diff --git a/fs/namei.c b/fs/namei.c
index af3783fff1de..dd5c9f0bf829 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -226,6 +226,16 @@ int generic_permission(struct inode *inode, int mask,
         return -EACCES;
 }
 
+/**
+ * inode_permission  -  check for access rights to a given inode
+ * @inode:      inode to check permission on
+ * @mask:       right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
+ *
+ * Used to check for read/write/execute permissions on an inode.
+ * We use "fsuid" for this, letting us set arbitrary permissions
+ * for filesystem access without changing the "normal" uids which
+ * are used for other things.
+ */
 int inode_permission(struct inode *inode, int mask)
 {
         int retval;
@@ -247,7 +257,6 @@ int inode_permission(struct inode *inode, int mask)
                         return -EACCES;
         }
 
-        /* Ordinary permission routines do not understand MAY_APPEND. */
         if (inode->i_op && inode->i_op->permission)
                 retval = inode->i_op->permission(inode, mask);
         else
@@ -265,21 +274,6 @@ int inode_permission(struct inode *inode, int mask)
 }
 
 /**
- * vfs_permission  -  check for access rights to a given path
- * @nd:         lookup result that describes the path
- * @mask:       right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
- *
- * Used to check for read/write/execute permissions on a path.
- * We use "fsuid" for this, letting us set arbitrary permissions
- * for filesystem access without changing the "normal" uids which
- * are used for other things.
- */
-int vfs_permission(struct nameidata *nd, int mask)
-{
-        return inode_permission(nd->path.dentry->d_inode, mask);
-}
-
-/**
  * file_permission  -  check for additional access rights to a given file
  * @file:       file to check access rights for
  * @mask:       right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
@@ -289,7 +283,7 @@ int vfs_permission(struct nameidata *nd, int mask)
  *
  * Note:
  *      Do not use this function in new code.  All access checks should
- *      be done using vfs_permission().
+ *      be done using inode_permission().
  */
 int file_permission(struct file *file, int mask)
 {
@@ -527,18 +521,6 @@ out_unlock:
         return result;
 }
 
-/* SMP-safe */
-static __always_inline void
-walk_init_root(const char *name, struct nameidata *nd)
-{
-        struct fs_struct *fs = current->fs;
-
-        read_lock(&fs->lock);
-        nd->path = fs->root;
-        path_get(&fs->root);
-        read_unlock(&fs->lock);
-}
-
 /*
  * Wrapper to retry pathname resolution whenever the underlying
  * file system returns an ESTALE.
@@ -576,9 +558,16 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
                 goto fail;
 
         if (*link == '/') {
+                struct fs_struct *fs = current->fs;
+
                 path_put(&nd->path);
-                walk_init_root(link, nd);
+
+                read_lock(&fs->lock);
+                nd->path = fs->root;
+                path_get(&fs->root);
+                read_unlock(&fs->lock);
         }
+
         res = link_path_walk(link, nd);
         if (nd->depth || res || nd->last_type!=LAST_NORM)
                 return res;
@@ -859,7 +848,8 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
                 nd->flags |= LOOKUP_CONTINUE;
                 err = exec_permission_lite(inode);
                 if (err == -EAGAIN)
-                        err = vfs_permission(nd, MAY_EXEC);
+                        err = inode_permission(nd->path.dentry->d_inode,
+                                               MAY_EXEC);
                 if (err)
                         break;
 
@@ -1493,9 +1483,9 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
         return error;
 }
 
-int may_open(struct nameidata *nd, int acc_mode, int flag)
+int may_open(struct path *path, int acc_mode, int flag)
 {
-        struct dentry *dentry = nd->path.dentry;
+        struct dentry *dentry = path->dentry;
         struct inode *inode = dentry->d_inode;
         int error;
 
@@ -1516,13 +1506,13 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
         if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
                 flag &= ~O_TRUNC;
         } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
-                if (nd->path.mnt->mnt_flags & MNT_NODEV)
+                if (path->mnt->mnt_flags & MNT_NODEV)
                         return -EACCES;
 
                 flag &= ~O_TRUNC;
         }
 
-        error = vfs_permission(nd, acc_mode);
+        error = inode_permission(inode, acc_mode);
         if (error)
                 return error;
         /*
@@ -1556,6 +1546,9 @@ 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(path, 0,
+                                               ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
                 if (!error) {
                         DQUOT_INIT(inode);
 
@@ -1586,14 +1579,18 @@ 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;
         if (error)
                 return error;
         /* Don't check for write permission, don't truncate */
-        return may_open(nd, 0, flag & ~O_TRUNC);
+        return may_open(&nd->path, 0, flag & ~O_TRUNC);
 }
 
 /*
@@ -1779,7 +1776,7 @@ ok:
                 if (error)
                         goto exit;
         }
-        error = may_open(&nd, acc_mode, flag);
+        error = may_open(&nd.path, acc_mode, flag);
         if (error) {
                 if (will_write)
                         mnt_drop_write(nd.path.mnt);
@@ -1999,6 +1996,9 @@ 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 +2011,7 @@ 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 +2071,11 @@ 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 +2185,11 @@ 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 +2274,11 @@ 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 +2359,11 @@ 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 +2460,11 @@ 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 +2700,13 @@ 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);
@@ -2750,13 +2776,16 @@ int vfs_follow_link(struct nameidata *nd, const char *link)
 /* get the link contents into pagecache */
 static char *page_getlink(struct dentry * dentry, struct page **ppage)
 {
-        struct page * page;
+        char *kaddr;
+        struct page *page;
         struct address_space *mapping = dentry->d_inode->i_mapping;
         page = read_mapping_page(mapping, 0, NULL);
         if (IS_ERR(page))
                 return (char*)page;
         *ppage = page;
-        return kmap(page);
+        kaddr = kmap(page);
+        nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
+        return kaddr;
 }
 
 int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
@@ -2849,7 +2878,6 @@ EXPORT_SYMBOL(path_lookup);
 EXPORT_SYMBOL(kern_path);
 EXPORT_SYMBOL(vfs_path_lookup);
 EXPORT_SYMBOL(inode_permission);
-EXPORT_SYMBOL(vfs_permission);
 EXPORT_SYMBOL(file_permission);
 EXPORT_SYMBOL(unlock_rename);
 EXPORT_SYMBOL(vfs_create);
@@ -2865,3 +2893,10 @@ EXPORT_SYMBOL(vfs_symlink);
 EXPORT_SYMBOL(vfs_unlink);
 EXPORT_SYMBOL(dentry_unhash);
 EXPORT_SYMBOL(generic_readlink);
+
+/* to be mentioned only in INIT_TASK */
+struct fs_struct init_fs = {
+        .count          = ATOMIC_INIT(1),
+        .lock           = __RW_LOCK_UNLOCKED(init_fs.lock),
+        .umask          = 0022,
+};