Fix export_args ex_flags field so that is 64bits, the same as mnt_flags.

Since mnt_flags was upgraded to 64bits there has been a quirk in
"struct export_args", since it hold a copy of mnt_flags
in ex_flags, which is an "int" (32bits).
This happens to currently work, since all the flag bits used in ex_flags are
defined in the low order 32bits. However, new export flags cannot be defined.
Also, ex_anon is a "struct xucred", which limits it to 16 additional groups.
This patch revises "struct export_args" to make ex_flags 64bits and replaces
ex_anon with ex_uid, ex_ngroups and ex_groups (which points to a
groups list, so it can be malloc'd up to NGROUPS in size.
This requires that the VFS_CHECKEXP() arguments change, so I also modified the
last "secflavors" argument to be an array pointer, so that the
secflavors could be copied in VFS_CHECKEXP() while the export entry is locked.
(Without this patch VFS_CHECKEXP() returns a pointer to the secflavors
array and then it is used after being unlocked, which is potentially
a problem if the exports entry is changed.
In practice this does not occur when mountd is run with "-S",
but I think it is worth fixing.)

This patch also deleted the vfs_oexport_conv() function, since
do_mount_update() does the conversion, as required by the old vfs_cmount()
calls.

Reviewed by:	kib, freqlabs
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D25088

1 files changed, 1 insertions, 3 deletions

diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
index 22ab5829fba2..2d0c10d519e3 100644
--- a/sys/fs/msdosfs/msdosfs_vfsops.c
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c
@@ -190,7 +190,6 @@ static int
 msdosfs_cmount(struct mntarg *ma, void *data, uint64_t flags)
 {
 	struct msdosfs_args args;
-	struct export_args exp;
 	int error;
 
 	if (data == NULL)
@@ -198,10 +197,9 @@ msdosfs_cmount(struct mntarg *ma, void *data, uint64_t flags)
 	error = copyin(data, &args, sizeof args);
 	if (error)
 		return (error);
-	vfs_oexport_conv(&args.export, &exp);
 
 	ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
-	ma = mount_arg(ma, "export", &exp, sizeof(exp));
+	ma = mount_arg(ma, "export", &args.export, sizeof(args.export));
 	ma = mount_argf(ma, "uid", "%d", args.uid);
 	ma = mount_argf(ma, "gid", "%d", args.gid);
 	ma = mount_argf(ma, "mask", "%d", args.mask);