From 55725513b5ef9d462aa3e18527658a0362aaae83 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 18 Apr 2012 12:48:35 -0400 Subject: [PATCH 1/1] NFSv4: Ensure that we check lock exclusive/shared type against open modes Since we may be simulating flock() locks using NFS byte range locks, we can't rely on the VFS having checked the file open mode for us. Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org --- fs/nfs/nfs4proc.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 3c787d02131b..ba837d977a1a 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4726,6 +4726,20 @@ nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request) if (state == NULL) return -ENOLCK; + /* + * Don't rely on the VFS having checked the file open mode, + * since it won't do this for flock() locks. + */ + switch (request->fl_type & (F_RDLCK|F_WRLCK|F_UNLCK)) { + case F_RDLCK: + if (!(filp->f_mode & FMODE_READ)) + return -EBADF; + break; + case F_WRLCK: + if (!(filp->f_mode & FMODE_WRITE)) + return -EBADF; + } + do { status = nfs4_proc_setlk(state, cmd, request); if ((status != -EAGAIN) || IS_SETLK(cmd)) -- 2.39.2