[PATCH 008/102] NFSv4: Fix the string length returned by the idmapper

From: Luis Henriques
Date: Mon Apr 08 2013 - 06:22:44 EST


3.5.7.10 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>

commit cf4ab538f1516606d3ae730dce15d6f33d96b7e1 upstream.

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>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 a0972e9..e4476dc 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -710,9 +710,9 @@ 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);
}
@@ -720,15 +720,18 @@ static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *dat
static int nfs_idmap_read_message(struct idmap_msg *im, struct key *key, struct key *authkey)
{
char id_str[NFS_UINT_MAXLEN];
+ size_t len;
int ret = -EINVAL;

switch (im->im_conv) {
case IDMAP_CONV_NAMETOID:
- 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:
- 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;
}

--
1.8.1.2

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