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@xxxxxxxxxx>
---
fs/nfs/nfs4file.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index f58c17b..dcd39d4 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -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--;
--
1.7.1
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