From f6d3944b30bba96911b06b990ff9538a24006cb4 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 18 Apr 2012 12:48:35 -0400 Subject: [PATCH] NFSv4: Ensure that we check lock exclusive/shared type against open modes commit 55725513b5ef9d462aa3e18527658a0362aaae83 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- fs/nfs/nfs4proc.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 28a5f98d2ebf..2612223d96e3 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4608,6 +4608,20 @@ 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)) -- 2.39.5