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namei: expand nested_symlink() in its only caller 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
hifive-unleashed-5.1
Al Viro 2015-04-17 23:44:45 -04:00
parent 896475d5bd
commit 5a460275ef
1 changed files with 23 additions and 38 deletions
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61
fs/namei.c
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@ -1612,43 +1612,6 @@ out_err:
return err;
}
/*
* This limits recursive symlink follows to 8, while
* limiting consecutive symlinks to 40.
*
* Without that kind of total limit, nasty chains of consecutive
* symlinks can cause almost arbitrarily long lookups.
*/
static inline int nested_symlink(struct nameidata *nd)
{
int res;
if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
path_put_conditional(&nd->link, nd);
path_put(&nd->path);
return -ELOOP;
}
BUG_ON(nd->depth >= MAX_NESTED_LINKS);
nd->depth++;
current->link_count++;
do {
struct path link = nd->link;
void *cookie;
res = follow_link(&link, nd, &cookie);
if (res)
break;
res = walk_component(nd, LOOKUP_FOLLOW);
put_link(nd, &link, cookie);
} while (res > 0);
current->link_count--;
nd->depth--;
return res;
}
/*
* We can do the critical dentry name comparison and hashing
* operations one word at a time, but we are limited to:
@ -1839,7 +1802,29 @@ static int link_path_walk(const char *name, struct nameidata *nd)
return err;
if (err) {
err = nested_symlink(nd);
if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
path_put_conditional(&nd->link, nd);
path_put(&nd->path);
return -ELOOP;
}
BUG_ON(nd->depth >= MAX_NESTED_LINKS);
nd->depth++;
current->link_count++;
do {
struct path link = nd->link;
void *cookie;
err = follow_link(&link, nd, &cookie);
if (err)
break;
err = walk_component(nd, LOOKUP_FOLLOW);
put_link(nd, &link, cookie);
} while (err > 0);
current->link_count--;
nd->depth--;
if (err)
return err;
}