From 64a38e840ce5940253208eaba40265c73decc4ee Mon Sep 17 00:00:00 2001 From: Dave Wysochanski Date: Fri, 26 Jul 2019 18:33:01 -0400 Subject: SUNRPC: Track writers of the 'channel' file to improve cache_listeners_exist The sunrpc cache interface is susceptible to being fooled by a rogue process just reading a 'channel' file. If this happens the kernel may think a valid daemon exists to service the cache when it does not. For example, the following may fool the kernel: cat /proc/net/rpc/auth.unix.gid/channel Change the tracking of readers to writers when considering whether a listener exists as all valid daemon processes either open a channel file O_RDWR or O_WRONLY. While this does not prevent a rogue process from "stealing" a message from the kernel, it does at least improve the kernels perception of whether a valid process servicing the cache exists. Signed-off-by: Dave Wysochanski Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index c7f38e897174..f7d086b77a21 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -107,9 +107,9 @@ struct cache_detail { /* fields for communication over channel */ struct list_head queue; - atomic_t readers; /* how many time is /chennel open */ - time_t last_close; /* if no readers, when did last close */ - time_t last_warn; /* when we last warned about no readers */ + atomic_t writers; /* how many time is /channel open */ + time_t last_close; /* if no writers, when did last close */ + time_t last_warn; /* when we last warned about no writers */ union { struct proc_dir_entry *procfs; -- cgit v1.2.3 From d6dfe43ec6062beea5ba1172b957e74a13c95b86 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 16 Aug 2019 17:48:36 -0400 Subject: svcrdma: Remove svc_rdma_wq Clean up: the system workqueue will work just as well. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/svc_rdma.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index 981f0d726ad4..edb39900fe04 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -200,7 +200,6 @@ extern struct svc_xprt_class svc_rdma_bc_class; #endif /* svc_rdma.c */ -extern struct workqueue_struct *svc_rdma_wq; extern int svc_rdma_init(void); extern void svc_rdma_cleanup(void); -- cgit v1.2.3 From 4866073e6ddf03066c925d3237903d7f4ca68982 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 16 Aug 2019 17:49:38 -0400 Subject: svcrdma: Use llist for managing cache of recv_ctxts Use a wait-free mechanism for managing the svc_rdma_recv_ctxts free list. Subsequently, sc_recv_lock can be eliminated. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/svc_rdma.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index edb39900fe04..40f65888dd38 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -42,6 +42,7 @@ #ifndef SVC_RDMA_H #define SVC_RDMA_H +#include #include #include #include @@ -107,8 +108,7 @@ struct svcxprt_rdma { struct list_head sc_read_complete_q; struct work_struct sc_work; - spinlock_t sc_recv_lock; - struct list_head sc_recv_ctxts; + struct llist_head sc_recv_ctxts; }; /* sc_flags */ #define RDMAXPRT_CONN_PENDING 3 @@ -125,6 +125,7 @@ enum { #define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD struct svc_rdma_recv_ctxt { + struct llist_node rc_node; struct list_head rc_list; struct ib_recv_wr rc_recv_wr; struct ib_cqe rc_cqe; -- cgit v1.2.3 From f69d6d8eef7807f8d937b81da24bebd2e926e4d2 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Sun, 18 Aug 2019 14:18:44 -0400 Subject: sunrpc: add a new cache_detail operation for when a cache is flushed When the exports table is changed, exportfs will usually write a new time to the "flush" file in the nfsd.export cache procfile. This tells the kernel to flush any entries that are older than that value. This gives us a mechanism to tell whether an unexport might have occurred. Add a new ->flush cache_detail operation that is called after flushing the cache whenever someone writes to a "flush" file. Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index f7d086b77a21..f8603724fbee 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -87,6 +87,7 @@ struct cache_detail { int has_died); struct cache_head * (*alloc)(void); + void (*flush)(void); int (*match)(struct cache_head *orig, struct cache_head *new); void (*init)(struct cache_head *orig, struct cache_head *new); void (*update)(struct cache_head *orig, struct cache_head *new); -- cgit v1.2.3