Re: [PATCH v3 1/1] NFSD: fix use-after-free in __nfs42_ssc_open()
From: Chuck Lever III <hidden>
Date: 2022-12-13 14:09:21
On Dec 12, 2022, at 5:50 PM, Dai Ngo [off-list ref] wrote: 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 <redacted> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
LGTM. Thanks for your quick response! I'll wait for review comments before applying.
quoted hunk ↗ jump to hunk
--- 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 8beb2bc4c328..b79ee65ae016 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c@@ -1463,13 +1463,6 @@ nfsd4_interssc_connect(struct nl4_server *nss, struct svc_rqst *rqstp,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. *@@ -1572,11 +1565,6 @@ 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)@@ -1771,7 +1759,7 @@ 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,@@ -1852,8 +1840,10 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,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; } -- 2.9.5
-- Chuck Lever