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NFSv4: Ensure that we check lock exclusive/shared type against open modes

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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 <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Trond Myklebust 2012-04-18 12:48:35 -04:00
parent 05ffe24f52
commit 55725513b5
1 changed files with 14 additions and 0 deletions
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14
fs/nfs/nfs4proc.c
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@ -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))