On Fri, 2013-03-08 at 11:11 -0600, Dave Chiluk wrote:
> As of commit 57e62324e469e092ecc6c94a7a86fe4bd6ac5172, the SETATTR nfsv4
> command now null terminates fattr_owner and fattr_owner_group.
>
> Here is an example excerpt from a tcpdump
> Opcode: SETATTR (34)
> stateid
> [StateID Hash: 0xafa9]
> seqid: 0x00000000
> Data: 000000000000000000000000
> obj_attributes
> attrmask
> recc_attr: FATTR4_OWNER_GROUP (37)
> fattr4_owner_group: groupname@xxxxxxxxxxxxxx
> length: 25
>
> This means that even though there are actually 24 characters in
> groupname@xxxxxxxxxxxxxx, we now send 24 characters + 1 null character.
> Hence the total length of 25. Previously the client would send just the
> 24 characters and set length to 24.
>
> This isn't an issue for communication with other Linux machines, but it
> is an issue for interaction with AIX machines. As is discussed here.
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1101292
>
> I attempted to read the RFC available here
> http://tools.ietf.org/html/rfc5661, but have not been able to find a
> statement instructing one way or the other.
>
> So the question becomes, is it correct for linux to be sending this null
> terminator when read against the RFC, or is it AIX's responsibility to
> handle null-terminated strings?
The client is definitely in error here according to RFC3530. Please
check if the attached patch fixes the issue for you.
Cheers
Trond
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
From 90eabc5dfde58de5c37de3866f427da02e86ce17 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Date: Fri, 8 Mar 2013 12:56:37 -0500
Subject: [PATCH] NFSv4: Fix the string length returned by the idmapper
Functions like nfs_map_uid_to_name() and nfs_map_gid_to_group() are
expected to return a string without any terminating NUL character.
Regression introduced by commit 57e62324e469e092ecc6c94a7a86fe4bd6ac5172
(NFS: Store the legacy idmapper result in the keyring).
Reported-by: Dave Chiluk <dave.chiluk@xxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: Bryan Schumaker <bjschuma@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx [>=3.4]
---
fs/nfs/idmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index dc0f98d..c516da5 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -726,9 +726,9 @@ out1:
return ret;
}
-static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data)
+static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
{
- return key_instantiate_and_link(key, data, strlen(data) + 1,
+ return key_instantiate_and_link(key, data, datalen,
id_resolver_cache->thread_keyring,
authkey);
}
@@ -738,6 +738,7 @@ static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
struct key *key, struct key *authkey)
{
char id_str[NFS_UINT_MAXLEN];
+ size_t len;
int ret = -ENOKEY;
/* ret = -ENOKEY */
@@ -747,13 +748,15 @@ static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
case IDMAP_CONV_NAMETOID:
if (strcmp(upcall->im_name, im->im_name) != 0)
break;
- sprintf(id_str, "%d", im->im_id);
- ret = nfs_idmap_instantiate(key, authkey, id_str);
+ /* Note: here we store the NUL terminator too */
+ len = sprintf(id_str, "%d", im->im_id) + 1;
+ ret = nfs_idmap_instantiate(key, authkey, id_str, len);
break;
case IDMAP_CONV_IDTONAME:
if (upcall->im_id != im->im_id)
break;
- ret = nfs_idmap_instantiate(key, authkey, im->im_name);
+ len = strlen(im->im_name);
+ ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
break;
default:
ret = -EINVAL;
--
1.8.1.4
