From ebd09abbd9699f328165aee50a070403fbf55a37 Mon Sep 17 00:00:00 2001 From: Duane Griffin Date: Fri, 19 Dec 2008 20:47:12 +0000 Subject: [PATCH] vfs: ensure page symlinks are NUL-terminated On-disk data corruption could cause a page link to have its i_size set to PAGE_SIZE (or a multiple thereof) and its contents all non-NUL. NUL-terminate the link name to ensure this doesn't cause further problems for the kernel. Cc: Al Viro Cc: Andrew Morton Signed-off-by: Duane Griffin Signed-off-by: Al Viro --- fs/namei.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index ab441af4196b..9ed5e2818f80 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2786,13 +2786,16 @@ 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)