[ 14/38] NFS: fix bug in legacy DNS resolver.

[Greg Kroah-Hartman]

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

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

From: NeilBrown <neilb@xxxxxxx>

commit 8d96b10639fb402357b75b055b1e82a65ff95050 upstream.

The DNS resolver's use of the sunrpc cache involves a 'ttl' number
(relative) rather that a timeout (absolute).  This confused me when
I wrote
  commit c5b29f885afe890f953f7f23424045cdad31d3e4
     "sunrpc: use seconds since boot in expiry cache"

and I managed to break it.  The effect is that any TTL is interpreted
as 0, and nothing useful gets into the cache.

This patch removes the use of get_expiry() - which really expects an
expiry time - and uses get_uint() instead, treating the int correctly
as a ttl.

This fixes a regression that has been present since 2.6.37, causing
certain NFS accesses in certain environments to incorrectly fail.

Reported-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Tested-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfs/dns_resolve.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -213,7 +213,7 @@ static int nfs_dns_parse(struct cache_de
 {
 	char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
 	struct nfs_dns_ent key, *item;
-	unsigned long ttl;
+	unsigned int ttl;
 	ssize_t len;
 	int ret = -EINVAL;
 
@@ -236,7 +236,8 @@ static int nfs_dns_parse(struct cache_de
 	key.namelen = len;
 	memset(&key.h, 0, sizeof(key.h));
 
-	ttl = get_expiry(&buf);
+	if (get_uint(&buf, &ttl) < 0)
+		goto out;
 	if (ttl == 0)
 		goto out;
 	key.h.expiry_time = ttl + seconds_since_boot();


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/