vn_open_cred(): disallow O_CREAT | O_EMPTY_PATH

This combination does not make sense, and cannot be satisfied by lookup.
In particular, lookup cannot supply dvp, it only can directly return vp.

Reported and reviewed by:	markj using syzkaller
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
This commit is contained in:
Konstantin Belousov 2021-05-12 22:04:44 +03:00
parent 529ab5a759
commit 6de3cf14c4

View File

@ -233,7 +233,8 @@ vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
first_open = false;
fmode = *flagp;
if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
O_EXCL | O_DIRECTORY))
O_EXCL | O_DIRECTORY) ||
(fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH))
return (EINVAL);
else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;