2013-03-22 15:53:46

by Dave Chiluk

[permalink] [raw]
Subject: [PATCH] NFSv4: Fix the string length returned by the idmapper

From: Trond Myklebust <[email protected]>

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).

This fixes inability to chown on chgrp files on AIX nfs shares.

Reported-by: Dave Chiluk <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Cc: Bryan Schumaker <[email protected]>
Cc: [email protected] [>=3.4]
---
fs/nfs/idmap.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index dc0f98d..99e9ec6 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -726,9 +726,10 @@ 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 +739,7 @@ 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 +749,15 @@ 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;
--
1.7.9.5