NFSv2 file locking currently fails the Connectathon tests, because the
calls to the VFS locking code do not return an EINVAL error if the
struct file_lock overflows the 32-bit boundaries.
The problem is due to the fact that we occasionally call helpers from
fs/locks.c in order to avoid RPC calls to the server when we know that a
local process holds the lock. These helpers are, of course, always
64-bit enabled, so EINVAL is not returned in cases when it would if
the call had gone to the NLM code.
For consistency, we therefore add support for a bounds-checking helper.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
---
fs/nfs/file.c | 20 +++++++++++++++-----
fs/nfs/proc.c | 24 ++++++++++++++++++++++++
include/linux/nfs_xdr.h | 1 +
3 files changed, 40 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index d84a3d8..7c73f06 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -593,6 +593,7 @@ out:
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode * inode = filp->f_mapping->host;
+ int ret = -ENOLCK;
dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
inode->i_sb->s_id, inode->i_ino,
@@ -602,13 +603,22 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
/* No mandatory locks over NFS */
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
- return -ENOLCK;
+ goto out_err;
+
+ if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
+ ret = NFS_PROTO(inode)->lock_check_bounds(fl);
+ if (ret < 0)
+ goto out_err;
+ }
if (IS_GETLK(cmd))
- return do_getlk(filp, cmd, fl);
- if (fl->fl_type == F_UNLCK)
- return do_unlk(filp, cmd, fl);
- return do_setlk(filp, cmd, fl);
+ ret = do_getlk(filp, cmd, fl);
+ else if (fl->fl_type == F_UNLCK)
+ ret = do_unlk(filp, cmd, fl);
+ else
+ ret = do_setlk(filp, cmd, fl);
+out_err:
+ return ret;
}
/*
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 03599bf..5c35b02 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -598,6 +598,29 @@ nfs_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
}
+/* Helper functions for NFS lock bounds checking */
+#define NFS_LOCK32_OFFSET_MAX ((__s32)0x7fffffffUL)
+static int nfs_lock_check_bounds(const struct file_lock *fl)
+{
+ __s32 start, end;
+
+ start = (__s32)fl->fl_start;
+ if ((loff_t)start != fl->fl_start)
+ goto out_einval;
+
+ if (fl->fl_end != OFFSET_MAX) {
+ end = (__s32)fl->fl_end;
+ if ((loff_t)end != fl->fl_end)
+ goto out_einval;
+ } else
+ end = NFS_LOCK32_OFFSET_MAX;
+
+ if (start < 0 || start > end)
+ goto out_einval;
+ return 0;
+out_einval:
+ return -EINVAL;
+}
const struct nfs_rpc_ops nfs_v2_clientops = {
.version = 2, /* protocol version */
@@ -633,4 +656,5 @@ const struct nfs_rpc_ops nfs_v2_clientops = {
.file_open = nfs_open,
.file_release = nfs_release,
.lock = nfs_proc_lock,
+ .lock_check_bounds = nfs_lock_check_bounds,
};
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 24263bb..8d780de 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -832,6 +832,7 @@ struct nfs_rpc_ops {
int (*file_open) (struct inode *, struct file *);
int (*file_release) (struct inode *, struct file *);
int (*lock)(struct file *, int, struct file_lock *);
+ int (*lock_check_bounds)(const struct file_lock *);
void (*clear_acl_cache)(struct inode *);
};
--
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