From bd86c69dae65de30f6d47249418ba7889809e31a Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Mon, 10 Oct 2022 14:59:02 +0900
Subject: [PATCH 1/2] NFSD: unregister shrinker when nfsd_init_net() fails
syzbot is reporting UAF read at register_shrinker_prepared() [1], for
commit 7746b32f467b3813 ("NFSD: add shrinker to reap courtesy clients on
low memory condition") missed that nfsd4_leases_net_shutdown() from
nfsd_exit_net() is called only when nfsd_init_net() succeeded.
If nfsd_init_net() fails due to nfsd_reply_cache_init() failure,
register_shrinker() from nfsd4_init_leases_net() has to be undone
before nfsd_init_net() returns.
Link: https://syzkaller.appspot.com/bug?extid=ff796f04613b4c84ad89 [1]
Reported-by: syzbot <syzbot+ff796f04613b4c84ad89@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 7746b32f467b3813 ("NFSD: add shrinker to reap courtesy clients on low memory condition")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfsctl.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 6a29bcfc93909..dc74a947a440c 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1458,12 +1458,14 @@ static __net_init int nfsd_init_net(struct net *net)
goto out_drc_error;
retval = nfsd_reply_cache_init(nn);
if (retval)
- goto out_drc_error;
+ goto out_cache_error;
get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
seqlock_init(&nn->writeverf_lock);
return 0;
+out_cache_error:
+ nfsd4_leases_net_shutdown(nn);
out_drc_error:
nfsd_idmap_shutdown(net);
out_idmap_error:
From 93c128e709aec23b10f3a2f78a824080d4085318 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Wed, 12 Oct 2022 14:42:54 -0400
Subject: [PATCH 2/2] nfsd: ensure we always call fh_verify_error tracepoint
This is a conditional tracepoint. Call it every time, not just when
nfs_permission fails.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfsd/nfsfh.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index d73434200df98..8c52b6c9d31a2 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -392,8 +392,8 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
skip_pseudoflavor_check:
/* Finally, check access permissions. */
error = nfsd_permission(rqstp, exp, dentry, access);
- trace_nfsd_fh_verify_err(rqstp, fhp, type, access, error);
out:
+ trace_nfsd_fh_verify_err(rqstp, fhp, type, access, error);
if (error == nfserr_stale)
nfsd_stats_fh_stale_inc(exp);
return error;