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Commit ebd09abb authored by Duane Griffin's avatar Duane Griffin Committed by Al Viro
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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 <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDuane Griffin <duaneg@dghda.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 03514685

fs/namei.c

+5 −2
Original line number Diff line number Diff line
@@ -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)

{

	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)