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authorNeilBrown <neilb@suse.de>2007-04-17 12:01:41 +1000
committerGreg Kroah-Hartman <gregkh@suse.de>2007-05-01 17:05:53 -0700
commitbd8622520f56b6a0d453ab895ca3272328bf66d0 (patch)
tree7552a53b360d685b272e08070013c9607441a486
parentd2bc7047d6c512fb412acd5a2c150d266e5080cd (diff)
knfsd: Use a spinlock to protect sk_info_authunix
sk_info_authunix is not being protected properly so the object that it points to can be cache_put twice, leading to corruption. We borrow svsk->sk_defer_lock to provide the protection. We should probably rename that lock to have a more generic name - later. Thanks to Gabriel for reporting this. Cc: Greg Banks <gnb@melbourne.sgi.com> Cc: Gabriel Barazer <gabriel@oxeva.fr> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/sunrpc/svcauth_unix.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 0d1e8fb83b93..a568f9f541b9 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -383,7 +383,10 @@ void svcauth_unix_purge(void)
static inline struct ip_map *
ip_map_cached_get(struct svc_rqst *rqstp)
{
- struct ip_map *ipm = rqstp->rq_sock->sk_info_authunix;
+ struct ip_map *ipm;
+ struct svc_sock *svsk = rqstp->rq_sock;
+ spin_lock_bh(&svsk->sk_defer_lock);
+ ipm = svsk->sk_info_authunix;
if (ipm != NULL) {
if (!cache_valid(&ipm->h)) {
/*
@@ -391,12 +394,14 @@ ip_map_cached_get(struct svc_rqst *rqstp)
* remembered, e.g. by a second mount from the
* same IP address.
*/
- rqstp->rq_sock->sk_info_authunix = NULL;
+ svsk->sk_info_authunix = NULL;
+ spin_unlock_bh(&svsk->sk_defer_lock);
cache_put(&ipm->h, &ip_map_cache);
return NULL;
}
cache_get(&ipm->h);
}
+ spin_unlock_bh(&svsk->sk_defer_lock);
return ipm;
}
@@ -405,9 +410,15 @@ ip_map_cached_put(struct svc_rqst *rqstp, struct ip_map *ipm)
{
struct svc_sock *svsk = rqstp->rq_sock;
- if (svsk->sk_sock->type == SOCK_STREAM && svsk->sk_info_authunix == NULL)
- svsk->sk_info_authunix = ipm; /* newly cached, keep the reference */
- else
+ spin_lock_bh(&svsk->sk_defer_lock);
+ if (svsk->sk_sock->type == SOCK_STREAM &&
+ svsk->sk_info_authunix == NULL) {
+ /* newly cached, keep the reference */
+ svsk->sk_info_authunix = ipm;
+ ipm = NULL;
+ }
+ spin_unlock_bh(&svsk->sk_defer_lock);
+ if (ipm)
cache_put(&ipm->h, &ip_map_cache);
}