diff options
| author | NeilBrown <neilb@suse.de> | 2007-04-16 22:53:25 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-04-17 16:36:27 -0700 |
| commit | 30f3deeee81cf22546da1b0b89a937bb991dea23 (patch) | |
| tree | 3747930c11b5cf0b25c96ddd161e541c1b00010c | |
| parent | 94256dd680f837dc14dd7d1377c5326fb3362721 (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>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | net/sunrpc/svcauth_unix.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index 9bae4090254..2bd23ea2aa8 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); } |