From 75333d48f92256a0dec91dbf07835e804fc411c0 Mon Sep 17 00:00:00 2001 From: Dai Ngo Date: Mon, 12 Dec 2022 14:50:11 -0800 Subject: [PATCH] NFSD: fix use-after-free in __nfs42_ssc_open() 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 Signed-off-by: Dai Ngo Tested-by: Xingyuan Mo Signed-off-by: Chuck Lever --- fs/nfsd/nfs4proc.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 73ed32ad23a2..bd880d55f565 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -1461,13 +1461,6 @@ 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. * @@ -1570,11 +1563,6 @@ nfsd4_cleanup_inter_ssc(struct vfsmount *ss_mnt, struct file *filp, { } -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) @@ -1770,7 +1758,7 @@ static int nfsd4_do_async_copy(void *data) default: nfserr = nfserr_offload_denied; } - nfsd4_interssc_disconnect(copy->ss_mnt); + /* ss_mnt will be unmounted by the laundromat */ goto do_callback; } nfserr = nfsd4_do_copy(copy, filp, copy->nf_dst->nf_file, @@ -1851,8 +1839,10 @@ out_err: if (async_copy) cleanup_async_copy(async_copy); status = nfserrno(-ENOMEM); - if (nfsd4_ssc_is_inter(copy)) - nfsd4_interssc_disconnect(copy->ss_mnt); + /* + * source's vfsmount of inter-copy will be unmounted + * by the laundromat + */ goto out; }