__dentry_path() fixes

* we need to save the starting point for restarts
* reject pathologically short buffers outright

Spotted-by: Denys Vlasenko <dvlasenk@redhat.com>
Spotted-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-01-26 12:37:55 -05:00
parent a8323da036
commit f650080152
1 changed files with 6 additions and 3 deletions

View File

@ -3116,19 +3116,22 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
/*
* Write full pathname from the root of the filesystem into the buffer.
*/
static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
static char *__dentry_path(struct dentry *d, char *buf, int buflen)
{
struct dentry *dentry;
char *end, *retval;
int len, seq = 0;
int error = 0;
if (buflen < 2)
goto Elong;
rcu_read_lock();
restart:
dentry = d;
end = buf + buflen;
len = buflen;
prepend(&end, &len, "\0", 1);
if (buflen < 1)
goto Elong;
/* Get '/' right */
retval = end-1;
*retval = '/';