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hostfs: sanitize symlinks

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2010-06-06 21:51:16 -04:00
parent c5322220eb
commit d0352d3ed7
1 changed files with 34 additions and 25 deletions
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59
fs/hostfs/hostfs_kern.c
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@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include "hostfs.h"
#include "init.h"
#include "kern.h"
@ -48,7 +49,7 @@ static int append = 0;
static const struct inode_operations hostfs_iops;
static const struct inode_operations hostfs_dir_iops;
static const struct address_space_operations hostfs_link_aops;
static const struct inode_operations hostfs_link_iops;
#ifndef MODULE
static int __init hostfs_args(char *options, int *add)
@ -471,8 +472,7 @@ static int read_name(struct inode *ino, char *name)
switch (st.mode & S_IFMT) {
case S_IFLNK:
ino->i_op = &page_symlink_inode_operations;
ino->i_mapping->a_ops = &hostfs_link_aops;
ino->i_op = &hostfs_link_iops;
break;
case S_IFDIR:
ino->i_op = &hostfs_dir_iops;
@ -835,32 +835,41 @@ static const struct inode_operations hostfs_dir_iops = {
.setattr = hostfs_setattr,
};
int hostfs_link_readpage(struct file *file, struct page *page)
static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
char *buffer, *name;
int err;
buffer = kmap(page);
name = inode_name(page->mapping->host);
if (name == NULL)
return -ENOMEM;
err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE);
kfree(name);
if (err == PAGE_CACHE_SIZE)
err = -E2BIG;
else if (err > 0) {
flush_dcache_page(page);
SetPageUptodate(page);
if (PageError(page)) ClearPageError(page);
err = 0;
char *link = __getname();
if (link) {
char *path = dentry_name(dentry);
int err = -ENOMEM;
if (path) {
int err = hostfs_do_readlink(path, link, PATH_MAX);
if (err == PATH_MAX)
err = -E2BIG;
kfree(path);
}
if (err < 0) {
__putname(link);
link = ERR_PTR(err);
}
} else {
link = ERR_PTR(-ENOMEM);
}
kunmap(page);
unlock_page(page);
return err;
nd_set_link(nd, link);
return NULL;
}
static const struct address_space_operations hostfs_link_aops = {
.readpage = hostfs_link_readpage,
static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
{
char *s = nd_get_link(nd);
if (!IS_ERR(s))
__putname(s);
}
static const struct inode_operations hostfs_link_iops = {
.readlink = generic_readlink,
.follow_link = hostfs_follow_link,
.put_link = hostfs_put_link,
};
static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)