1 files changed, 97 insertions, 63 deletions

diff --git a/fs/namei.c b/fs/namei.c
index af3783fff1de..f05bed242422 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;
@@ -247,8 +257,7 @@ 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)
+        if (inode->i_op->permission)
                 retval = inode->i_op->permission(inode, mask);
         else
                 retval = generic_permission(inode, mask, NULL);
@@ -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)
 {
@@ -438,7 +432,7 @@ static int exec_permission_lite(struct inode *inode)
 {
         umode_t mode = inode->i_mode;
 
-        if (inode->i_op && inode->i_op->permission)
+        if (inode->i_op->permission)
                 return -EAGAIN;
 
         if (current_fsuid() == inode->i_uid)
@@ -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;
 
@@ -918,9 +908,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
                 inode = next.dentry->d_inode;
                 if (!inode)
                         goto out_dput;
-                err = -ENOTDIR; 
-                if (!inode->i_op)
-                        goto out_dput;
 
                 if (inode->i_op->follow_link) {
                         err = do_follow_link(&next, nd);
@@ -930,9 +917,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
                         inode = nd->path.dentry->d_inode;
                         if (!inode)
                                 break;
-                        err = -ENOTDIR; 
-                        if (!inode->i_op)
-                                break;
                 } else
                         path_to_nameidata(&next, nd);
                 err = -ENOTDIR; 
@@ -971,7 +955,7 @@ last_component:
                         break;
                 inode = next.dentry->d_inode;
                 if ((lookup_flags & LOOKUP_FOLLOW)
-                    && inode && inode->i_op && inode->i_op->follow_link) {
+                    && inode && inode->i_op->follow_link) {
                         err = do_follow_link(&next, nd);
                         if (err)
                                 goto return_err;
@@ -983,7 +967,7 @@ last_component:
                         break;
                 if (lookup_flags & LOOKUP_DIRECTORY) {
                         err = -ENOTDIR; 
-                        if (!inode->i_op || !inode->i_op->lookup)
+                        if (!inode->i_op->lookup)
                                 break;
                 }
                 goto return_base;
@@ -1479,7 +1463,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
         if (error)
                 return error;
 
-        if (!dir->i_op || !dir->i_op->create)
+        if (!dir->i_op->create)
                 return -EACCES; /* shouldn't it be ENOSYS? */
         mode &= S_IALLUGO;
         mode |= S_IFREG;
@@ -1493,9 +1477,9 @@ 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 +1500,13 @@ 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 +1540,9 @@ 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 +1573,18 @@ 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);
 }
 
 /*
@@ -1755,7 +1746,7 @@ do_last:
         error = -ENOENT;
         if (!path.dentry->d_inode)
                 goto exit_dput;
-        if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link)
+        if (path.dentry->d_inode->i_op->follow_link)
                 goto do_link;
 
         path_to_nameidata(&path, &nd);
@@ -1779,7 +1770,7 @@ 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);
@@ -1936,7 +1927,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
         if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
                 return -EPERM;
 
-        if (!dir->i_op || !dir->i_op->mknod)
+        if (!dir->i_op->mknod)
                 return -EPERM;
 
         error = devcgroup_inode_mknod(mode, dev);
@@ -1999,6 +1990,9 @@ 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 +2005,7 @@ 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);
@@ -2034,7 +2029,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         if (error)
                 return error;
 
-        if (!dir->i_op || !dir->i_op->mkdir)
+        if (!dir->i_op->mkdir)
                 return -EPERM;
 
         mode &= (S_IRWXUGO|S_ISVTX);
@@ -2070,7 +2065,11 @@ 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);
@@ -2121,7 +2120,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
         if (error)
                 return error;
 
-        if (!dir->i_op || !dir->i_op->rmdir)
+        if (!dir->i_op->rmdir)
                 return -EPERM;
 
         DQUOT_INIT(dir);
@@ -2180,7 +2179,11 @@ 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);
@@ -2204,7 +2207,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
         if (error)
                 return error;
 
-        if (!dir->i_op || !dir->i_op->unlink)
+        if (!dir->i_op->unlink)
                 return -EPERM;
 
         DQUOT_INIT(dir);
@@ -2265,7 +2268,11 @@ 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);
@@ -2307,7 +2314,7 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
         if (error)
                 return error;
 
-        if (!dir->i_op || !dir->i_op->symlink)
+        if (!dir->i_op->symlink)
                 return -EPERM;
 
         error = security_inode_symlink(dir, dentry, oldname);
@@ -2346,7 +2353,11 @@ 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);
@@ -2384,7 +2395,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
          */
         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
                 return -EPERM;
-        if (!dir->i_op || !dir->i_op->link)
+        if (!dir->i_op->link)
                 return -EPERM;
         if (S_ISDIR(inode->i_mode))
                 return -EPERM;
@@ -2443,7 +2454,11 @@ 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);
@@ -2587,7 +2602,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
         if (error)
                 return error;
 
-        if (!old_dir->i_op || !old_dir->i_op->rename)
+        if (!old_dir->i_op->rename)
                 return -EPERM;
 
         DQUOT_INIT(old_dir);
@@ -2679,8 +2694,13 @@ 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 +2770,16 @@ 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)
@@ -2788,18 +2811,23 @@ void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
         }
 }
 
-int __page_symlink(struct inode *inode, const char *symname, int len,
-                gfp_t gfp_mask)
+/*
+ * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
+ */
+int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
 {
         struct address_space *mapping = inode->i_mapping;
         struct page *page;
         void *fsdata;
         int err;
         char *kaddr;
+        unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE;
+        if (nofs)
+                flags |= AOP_FLAG_NOFS;
 
 retry:
         err = pagecache_write_begin(NULL, mapping, 0, len-1,
-                                AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
+                                flags, &page, &fsdata);
         if (err)
                 goto fail;
 
@@ -2823,7 +2851,7 @@ fail:
 int page_symlink(struct inode *inode, const char *symname, int len)
 {
         return __page_symlink(inode, symname, len,
-                        mapping_gfp_mask(inode->i_mapping));
+                        !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS));
 }
 
 const struct inode_operations page_symlink_inode_operations = {
@@ -2849,7 +2877,6 @@ 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 +2892,10 @@ 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,
+};