From: Al Viro Date: Mon, 10 Dec 2018 22:30:41 +0000 (-0500) Subject: nfs_remount(): don't leak, don't ignore LSM options quietly X-Git-Tag: v5.15~7231^2~15 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6a0440e5b7562512c021aa1b5a706fcc545773db;p=platform%2Fkernel%2Flinux-starfive.git nfs_remount(): don't leak, don't ignore LSM options quietly * if mount(2) passes something like "context=foo" with MS_REMOUNT in flags (/sbin/mount.nfs will _not_ do that - you need to issue the syscall manually), you'll get leaked copies for LSM options. The reason is that instead of nfs_{alloc,free}_parsed_mount_data() nfs_remount() uses kzalloc/kfree, which lacks the needed cleanup. * selinux options are not changed on remount (as for any other fs), but in case of NFS the failure is quiet - they are not compared to what we used to have, with complaint in case of attempted changes. Trivially fixed by converting to use of security_sb_remount(). Reviewed-by: David Howells Signed-off-by: Al Viro --- diff --git a/fs/nfs/super.c b/fs/nfs/super.c index f9c8847..300bdd1 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -2254,7 +2254,7 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data) options->version <= 6)))) return 0; - data = kzalloc(sizeof(*data), GFP_KERNEL); + data = nfs_alloc_parsed_mount_data(); if (data == NULL) return -ENOMEM; @@ -2293,8 +2293,10 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data) /* compare new mount options with old ones */ error = nfs_compare_remount_data(nfss, data); + if (!error) + error = security_sb_remount(sb, &data->lsm_opts); out: - kfree(data); + nfs_free_parsed_mount_data(data); return error; } EXPORT_SYMBOL_GPL(nfs_remount);