diff options
| author | Martin Pieuchot <mpi@cvs.openbsd.org> | 2018-05-28 08:55:12 +0000 |
|---|---|---|
| committer | Martin Pieuchot <mpi@cvs.openbsd.org> | 2018-05-28 08:55:12 +0000 |
| commit | e7d195cdf41f4161b5851871187dace57b6c1b0c (patch) | |
| tree | 24b12765d4524fbefe6213f060a4963bdc6c6660 /sys/kern | |
| parent | fd1e9ad8d30cfeb9d0cec034161aeaf2c5a26f2e (diff) | |
Returns EBUSY if dup2(2) is called for a LARVAL file.
This prevents a panic due to a double free if a program exits after having
called accept(2) and dup2(2) on the same fd but without the corresponding
connect(5).
It will also allows us to simplify file descriptor locking. The error code
has been choosed to match Linux's behavior.
Pointed by Mathieu on tech@ after a discussion with guenther@. ok visa@
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_descrip.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index 1d0e4b73edf..2d048683cd4 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_descrip.c,v 1.158 2018/05/08 09:03:58 mpi Exp $ */ +/* $OpenBSD: kern_descrip.c,v 1.159 2018/05/28 08:55:11 mpi Exp $ */ /* $NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $ */ /* @@ -634,13 +634,14 @@ finishdup(struct proc *p, struct file *fp, int old, int new, return (EDEADLK); } - /* - * Don't fd_getfile here. We want to closef LARVAL files and - * closef can deal with that. - */ oldfp = fdp->fd_ofiles[new]; - if (oldfp != NULL) + if (oldfp != NULL) { + if (!FILE_IS_USABLE(oldfp)) { + FRELE(fp, p); + return (EBUSY); + } FREF(oldfp); + } fdp->fd_ofiles[new] = fp; fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] & ~UF_EXCLOSE; |