linux-kernel - [PATCH 2/2] nfsd: fix potential UAF in nfsd4_cb_getattr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240823-nfsd-fixes-v1-2-fc99aa16f6a0@kernel.org>
Date: Fri, 23 Aug 2024 18:27:39 -0400
From: Jeff Layton <jlayton@...nel.org>
To: Chuck Lever <chuck.lever@...cle.com>, Neil Brown <neilb@...e.de>, 
 Olga Kornievskaia <kolga@...app.com>, Dai Ngo <Dai.Ngo@...cle.com>, 
 Tom Talpey <tom@...pey.com>
Cc: linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Jeff Layton <jlayton@...nel.org>
Subject: [PATCH 2/2] nfsd: fix potential UAF in nfsd4_cb_getattr_release

Once we drop the delegation reference, the fields embedded in it are no
longer safe to access. Do that last.

Fixes: c5967721e106 ("NFSD: handle GETATTR conflict with write delegation")
Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
 fs/nfsd/nfs4state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 19d39872be32..02d43f95146e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3078,9 +3078,9 @@ nfsd4_cb_getattr_release(struct nfsd4_callback *cb)
 	struct nfs4_delegation *dp =
 			container_of(ncf, struct nfs4_delegation, dl_cb_fattr);
 
-	nfs4_put_stid(&dp->dl_stid);
 	clear_bit(CB_GETATTR_BUSY, &ncf->ncf_cb_flags);
 	wake_up_bit(&ncf->ncf_cb_flags, CB_GETATTR_BUSY);
+	nfs4_put_stid(&dp->dl_stid);
 }
 
 static const struct nfsd4_callback_ops nfsd4_cb_recall_any_ops = {

-- 
2.46.0