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nfs: verify open flags before allowing open

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Commit 9597c13b forbade opens with O_APPEND|O_DIRECT for NFSv4:

    nfs: verify open flags before allowing an atomic open

    Currently, you can open a NFSv4 file with O_APPEND|O_DIRECT, but cannot
    fcntl(F_SETFL,...) with those flags. This flag combination is explicitly
    forbidden on NFSv3 opens, and it seems like it should also be on NFSv4.

However, you can still open a file with O_DIRECT|O_APPEND if there exists a
cached dentry for the file because nfs4_file_open() is used instead of
nfs_atomic_open() and the check is bypassed.  Add the check in
nfs4_file_open() as well.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Benjamin Coddington 2015-06-25 09:25:50 -04:00 committed by Trond Myklebust
parent 0c8315dd56
commit 18a6008972
1 changed files with 4 additions and 0 deletions
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4
fs/nfs/nfs4file.c
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@ -41,6 +41,10 @@ nfs4_file_open(struct inode *inode, struct file *filp)
dprintk("NFS: open file(%pd2)\n", dentry);
err = nfs_check_flags(openflags);
if (err)
return err;
if ((openflags & O_ACCMODE) == 3)
openflags--;