The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=be10c0a910155709dc4e521db3349d50e0440018
commit be10c0a910155709dc4e521db3349d50e0440018
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2021-11-03 12:51:06 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2021-11-03 16:00:42 +0000
fexecve(2): allow O_PATH file descriptors opened without O_EXEC
This improves compatibility with Linux.
Noted by: Drew DeVault <s...@cmpwn.com>
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32821
---
lib/libc/sys/open.2 | 3 ---
sys/kern/kern_descrip.c | 5 +++--
sys/kern/kern_exec.c | 13 ++++++++++---
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/lib/libc/sys/open.2 b/lib/libc/sys/open.2
index da42c238a151..f6b061079ddf 100644
--- a/lib/libc/sys/open.2
+++ b/lib/libc/sys/open.2
@@ -334,9 +334,6 @@ but advisory locking is not allowed
.It Xr close 2
.It Xr fstat 2
.It Xr fexecve 2
-requires that
-.Dv O_EXEC
-was also specified at open time
.It Dv SCM_RIGHTS
can be passed over a
.Xr unix 4
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index a7e3785bc672..37d978e96de5 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -3213,8 +3213,9 @@ _fget(struct thread *td, int fd, struct file **fpp, int
flags,
error = EBADF;
break;
case FEXEC:
- if ((fp->f_flag & (FREAD | FEXEC)) == 0 ||
- ((fp->f_flag & FWRITE) != 0))
+ if (fp->f_ops != &path_fileops &&
+ ((fp->f_flag & (FREAD | FEXEC)) == 0 ||
+ (fp->f_flag & FWRITE) != 0))
error = EBADF;
break;
case 0:
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index c5b450b04240..575771346fd1 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -530,13 +530,20 @@ interpret:
}
} else {
AUDIT_ARG_FD(args->fd);
+
/*
- * Descriptors opened only with O_EXEC or O_RDONLY are allowed.
+ * If the descriptors was not opened with O_PATH, then
+ * we require that it was opened with O_EXEC or
+ * O_RDONLY. In either case, exec_check_permissions()
+ * below checks _current_ file access mode regardless
+ * of the permissions additionally checked at the
+ * open(2).
*/
error = fgetvp_exec(td, args->fd, &cap_fexecve_rights,
&newtextvp);
- if (error)
+ if (error != 0)
goto exec_fail;
+
if (vn_fullpath(newtextvp, &imgp->execpath,
&imgp->freepath) != 0)
imgp->execpath = args->fname;
@@ -881,7 +888,7 @@ interpret:
/*
* Store the vp for use in kern.proc.pathname. This vnode was
- * referenced by namei() or fgetvp_exec().
+ * referenced by namei() or by fexecve variant of fname handling.
*/
oldtextvp = p->p_textvp;
p->p_textvp = newtextvp;
