linux-kernel - [PATCH 5.4 60/76] NFS: nfs_igrab_and_active must first reference the superblock

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: <20210118113343.836686862@linuxfoundation.org>
Date:   Mon, 18 Jan 2021 12:35:00 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Trond Myklebust <trond.myklebust@...merspace.com>
Subject: [PATCH 5.4 60/76] NFS: nfs_igrab_and_active must first reference the superblock

From: Trond Myklebust <trond.myklebust@...merspace.com>

commit 896567ee7f17a8a736cda8a28cc987228410a2ac upstream.

Before referencing the inode, we must ensure that the superblock can be
referenced. Otherwise, we can end up with iput() calling superblock
operations that are no longer valid or accessible.

Fixes: ea7c38fef0b7 ("NFSv4: Ensure we reference the inode for return-on-close in delegreturn")
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/nfs/internal.h |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -569,12 +569,14 @@ extern void nfs4_test_session_trunk(stru
 
 static inline struct inode *nfs_igrab_and_active(struct inode *inode)
 {
-	inode = igrab(inode);
-	if (inode != NULL && !nfs_sb_active(inode->i_sb)) {
-		iput(inode);
-		inode = NULL;
+	struct super_block *sb = inode->i_sb;
+
+	if (sb && nfs_sb_active(sb)) {
+		if (igrab(inode))
+			return inode;
+		nfs_sb_deactive(sb);
 	}
-	return inode;
+	return NULL;
 }
 
 static inline void nfs_iput_and_deactive(struct inode *inode)