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NFS: Add correct bounds checking to NFSv2 locks

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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@netapp.com>
This commit is contained in:
Trond Myklebust 2008-05-20 19:34:39 -04:00
parent f3d47a3a6a
commit 2116271a34
3 changed files with 40 additions and 5 deletions
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20
fs/nfs/file.c
View file

@ -593,6 +593,7 @@ static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
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;
}
/*

24
fs/nfs/proc.c
View file

@ -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,
};

1
include/linux/nfs_xdr.h
View file

@ -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 *);
};