From: Dai Ngo <dai.ngo@oracle.com>
Date: Mon, 12 Dec 2022 14:50:11 -0800
Subject: [PATCH] NFSD: fix use-after-free in __nfs42_ssc_open()
Git-commit: 75333d48f92256a0dec91dbf07835e804fc411c0
Patch-mainline: v6.2-rc1
References: bsc#1206209 CVE-2022-4379
Problem caused by source's vfsmount being unmounted but remains
on the delayed unmount list. This happens when nfs42_ssc_open()
return errors.
Fixed by removing nfsd4_interssc_connect(), leave the vfsmount
for the laundromat to unmount when idle time expires.
We don't need to call nfs_do_sb_deactive when nfs42_ssc_open
return errors since the file was not opened so nfs_server->active
was not incremented. Same as in nfsd4_copy, if we fail to
launch nfsd4_do_async_copy thread then there's no need to
call nfs_do_sb_deactive
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Tested-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: NeilBrown <neilb@suse.com>
---
fs/nfsd/nfs4proc.c | 22 ++++++----------------
1 file changed, 6 insertions(+), 16 deletions(-)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1349,13 +1349,6 @@ out_err:
return status;
}
-static void
-nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
-{
- nfs_do_sb_deactive(ss_mnt->mnt_sb);
- mntput(ss_mnt);
-}
-
/*
* Verify COPY destination stateid.
*
@@ -1458,11 +1451,6 @@ nfsd4_cleanup_inter_ssc(struct vfsmount
{
}
-static void
-nfsd4_interssc_disconnect(struct vfsmount *ss_mnt)
-{
-}
-
static struct file *nfs42_ssc_open(struct vfsmount *ss_mnt,
struct nfs_fh *src_fh,
nfs4_stateid *stateid)
@@ -1620,14 +1608,14 @@ static int nfsd4_do_async_copy(void *dat
copy->nf_src = kzalloc(sizeof(struct nfsd_file), GFP_KERNEL);
if (!copy->nf_src) {
copy->nfserr = nfserr_serverfault;
- nfsd4_interssc_disconnect(copy->ss_mnt);
+ /* ss_mnt will be unmounted by the laundromat */
goto do_callback;
}
copy->nf_src->nf_file = nfs42_ssc_open(copy->ss_mnt, ©->c_fh,
©->stateid);
if (IS_ERR(copy->nf_src->nf_file)) {
copy->nfserr = nfserr_offload_denied;
- nfsd4_interssc_disconnect(copy->ss_mnt);
+ /* ss_mnt will be unmounted by the laundromat */
goto do_callback;
}
}
@@ -1712,8 +1700,10 @@ out_err:
if (async_copy)
cleanup_async_copy(async_copy);
status = nfserrno(-ENOMEM);
- if (!copy->cp_intra)
- nfsd4_interssc_disconnect(copy->ss_mnt);
+ /*
+ * source's vfsmount of inter-copy will be unmounted
+ * by the laundromat
+ */
goto out;
}