From d001648ec7cf8b21ae9eec8b9ba4a18295adfb14 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 30 Aug 2016 20:42:14 +0100 Subject: rxrpc: Don't expose skbs to in-kernel users [ver #2] Don't expose skbs to in-kernel users, such as the AFS filesystem, but instead provide a notification hook the indicates that a call needs attention and another that indicates that there's a new call to be collected. This makes the following possibilities more achievable: (1) Call refcounting can be made simpler if skbs don't hold refs to calls. (2) skbs referring to non-data events will be able to be freed much sooner rather than being queued for AFS to pick up as rxrpc_kernel_recv_data will be able to consult the call state. (3) We can shortcut the receive phase when a call is remotely aborted because we don't have to go through all the packets to get to the one cancelling the operation. (4) It makes it easier to do encryption/decryption directly between AFS's buffers and sk_buffs. (5) Encryption/decryption can more easily be done in the AFS's thread contexts - usually that of the userspace process that issued a syscall - rather than in one of rxrpc's background threads on a workqueue. (6) AFS will be able to wait synchronously on a call inside AF_RXRPC. To make this work, the following interface function has been added: int rxrpc_kernel_recv_data( struct socket *sock, struct rxrpc_call *call, void *buffer, size_t bufsize, size_t *_offset, bool want_more, u32 *_abort_code); This is the recvmsg equivalent. It allows the caller to find out about the state of a specific call and to transfer received data into a buffer piecemeal. afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction logic between them. They don't wait synchronously yet because the socket lock needs to be dealt with. Five interface functions have been removed: rxrpc_kernel_is_data_last() rxrpc_kernel_get_abort_code() rxrpc_kernel_get_error_number() rxrpc_kernel_free_skb() rxrpc_kernel_data_consumed() As a temporary hack, sk_buffs going to an in-kernel call are queued on the rxrpc_call struct (->knlrecv_queue) rather than being handed over to the in-kernel user. To process the queue internally, a temporary function, temp_deliver_data() has been added. This will be replaced with common code between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a future patch. Signed-off-by: David Howells Signed-off-by: David S. Miller --- fs/afs/cmservice.c | 142 +++++++++++++++++++++++++++++------------------------ 1 file changed, 77 insertions(+), 65 deletions(-) (limited to 'fs/afs/cmservice.c') diff --git a/fs/afs/cmservice.c b/fs/afs/cmservice.c index 77ee481059ac..2037e7a77a37 100644 --- a/fs/afs/cmservice.c +++ b/fs/afs/cmservice.c @@ -17,15 +17,12 @@ #include "internal.h" #include "afs_cm.h" -static int afs_deliver_cb_init_call_back_state(struct afs_call *, - struct sk_buff *, bool); -static int afs_deliver_cb_init_call_back_state3(struct afs_call *, - struct sk_buff *, bool); -static int afs_deliver_cb_probe(struct afs_call *, struct sk_buff *, bool); -static int afs_deliver_cb_callback(struct afs_call *, struct sk_buff *, bool); -static int afs_deliver_cb_probe_uuid(struct afs_call *, struct sk_buff *, bool); -static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *, - struct sk_buff *, bool); +static int afs_deliver_cb_init_call_back_state(struct afs_call *); +static int afs_deliver_cb_init_call_back_state3(struct afs_call *); +static int afs_deliver_cb_probe(struct afs_call *); +static int afs_deliver_cb_callback(struct afs_call *); +static int afs_deliver_cb_probe_uuid(struct afs_call *); +static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *); static void afs_cm_destructor(struct afs_call *); /* @@ -130,7 +127,7 @@ static void afs_cm_destructor(struct afs_call *call) * received. The step number here must match the final number in * afs_deliver_cb_callback(). */ - if (call->unmarshall == 6) { + if (call->unmarshall == 5) { ASSERT(call->server && call->count && call->request); afs_break_callbacks(call->server, call->count, call->request); } @@ -164,8 +161,7 @@ static void SRXAFSCB_CallBack(struct work_struct *work) /* * deliver request data to a CB.CallBack call */ -static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, - bool last) +static int afs_deliver_cb_callback(struct afs_call *call) { struct sockaddr_rxrpc srx; struct afs_callback *cb; @@ -174,7 +170,7 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, u32 tmp; int ret, loop; - _enter("{%u},{%u},%d", call->unmarshall, skb->len, last); + _enter("{%u}", call->unmarshall); switch (call->unmarshall) { case 0: @@ -185,7 +181,7 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, /* extract the FID array and its count in two steps */ case 1: _debug("extract FID count"); - ret = afs_extract_data(call, skb, last, &call->tmp, 4); + ret = afs_extract_data(call, &call->tmp, 4, true); if (ret < 0) return ret; @@ -202,8 +198,8 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, case 2: _debug("extract FID array"); - ret = afs_extract_data(call, skb, last, call->buffer, - call->count * 3 * 4); + ret = afs_extract_data(call, call->buffer, + call->count * 3 * 4, true); if (ret < 0) return ret; @@ -229,7 +225,7 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, /* extract the callback array and its count in two steps */ case 3: _debug("extract CB count"); - ret = afs_extract_data(call, skb, last, &call->tmp, 4); + ret = afs_extract_data(call, &call->tmp, 4, true); if (ret < 0) return ret; @@ -239,13 +235,11 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, return -EBADMSG; call->offset = 0; call->unmarshall++; - if (tmp == 0) - goto empty_cb_array; case 4: _debug("extract CB array"); - ret = afs_extract_data(call, skb, last, call->request, - call->count * 3 * 4); + ret = afs_extract_data(call, call->buffer, + call->count * 3 * 4, false); if (ret < 0) return ret; @@ -258,15 +252,9 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, cb->type = ntohl(*bp++); } - empty_cb_array: call->offset = 0; call->unmarshall++; - case 5: - ret = afs_data_complete(call, skb, last); - if (ret < 0) - return ret; - /* Record that the message was unmarshalled successfully so * that the call destructor can know do the callback breaking * work, even if the final ACK isn't received. @@ -275,7 +263,7 @@ static int afs_deliver_cb_callback(struct afs_call *call, struct sk_buff *skb, * updated also. */ call->unmarshall++; - case 6: + case 5: break; } @@ -310,19 +298,17 @@ static void SRXAFSCB_InitCallBackState(struct work_struct *work) /* * deliver request data to a CB.InitCallBackState call */ -static int afs_deliver_cb_init_call_back_state(struct afs_call *call, - struct sk_buff *skb, - bool last) +static int afs_deliver_cb_init_call_back_state(struct afs_call *call) { struct sockaddr_rxrpc srx; struct afs_server *server; int ret; - _enter(",{%u},%d", skb->len, last); + _enter(""); rxrpc_kernel_get_peer(afs_socket, call->rxcall, &srx); - ret = afs_data_complete(call, skb, last); + ret = afs_extract_data(call, NULL, 0, false); if (ret < 0) return ret; @@ -344,21 +330,61 @@ static int afs_deliver_cb_init_call_back_state(struct afs_call *call, /* * deliver request data to a CB.InitCallBackState3 call */ -static int afs_deliver_cb_init_call_back_state3(struct afs_call *call, - struct sk_buff *skb, - bool last) +static int afs_deliver_cb_init_call_back_state3(struct afs_call *call) { struct sockaddr_rxrpc srx; struct afs_server *server; + struct afs_uuid *r; + unsigned loop; + __be32 *b; + int ret; - _enter(",{%u},%d", skb->len, last); + _enter(""); rxrpc_kernel_get_peer(afs_socket, call->rxcall, &srx); - /* There are some arguments that we ignore */ - afs_data_consumed(call, skb); - if (!last) - return -EAGAIN; + _enter("{%u}", call->unmarshall); + + switch (call->unmarshall) { + case 0: + call->offset = 0; + call->buffer = kmalloc(11 * sizeof(__be32), GFP_KERNEL); + if (!call->buffer) + return -ENOMEM; + call->unmarshall++; + + case 1: + _debug("extract UUID"); + ret = afs_extract_data(call, call->buffer, + 11 * sizeof(__be32), false); + switch (ret) { + case 0: break; + case -EAGAIN: return 0; + default: return ret; + } + + _debug("unmarshall UUID"); + call->request = kmalloc(sizeof(struct afs_uuid), GFP_KERNEL); + if (!call->request) + return -ENOMEM; + + b = call->buffer; + r = call->request; + r->time_low = ntohl(b[0]); + r->time_mid = ntohl(b[1]); + r->time_hi_and_version = ntohl(b[2]); + r->clock_seq_hi_and_reserved = ntohl(b[3]); + r->clock_seq_low = ntohl(b[4]); + + for (loop = 0; loop < 6; loop++) + r->node[loop] = ntohl(b[loop + 5]); + + call->offset = 0; + call->unmarshall++; + + case 2: + break; + } /* no unmarshalling required */ call->state = AFS_CALL_REPLYING; @@ -390,14 +416,13 @@ static void SRXAFSCB_Probe(struct work_struct *work) /* * deliver request data to a CB.Probe call */ -static int afs_deliver_cb_probe(struct afs_call *call, struct sk_buff *skb, - bool last) +static int afs_deliver_cb_probe(struct afs_call *call) { int ret; - _enter(",{%u},%d", skb->len, last); + _enter(""); - ret = afs_data_complete(call, skb, last); + ret = afs_extract_data(call, NULL, 0, false); if (ret < 0) return ret; @@ -435,19 +460,14 @@ static void SRXAFSCB_ProbeUuid(struct work_struct *work) /* * deliver request data to a CB.ProbeUuid call */ -static int afs_deliver_cb_probe_uuid(struct afs_call *call, struct sk_buff *skb, - bool last) +static int afs_deliver_cb_probe_uuid(struct afs_call *call) { struct afs_uuid *r; unsigned loop; __be32 *b; int ret; - _enter("{%u},{%u},%d", call->unmarshall, skb->len, last); - - ret = afs_data_complete(call, skb, last); - if (ret < 0) - return ret; + _enter("{%u}", call->unmarshall); switch (call->unmarshall) { case 0: @@ -459,8 +479,8 @@ static int afs_deliver_cb_probe_uuid(struct afs_call *call, struct sk_buff *skb, case 1: _debug("extract UUID"); - ret = afs_extract_data(call, skb, last, call->buffer, - 11 * sizeof(__be32)); + ret = afs_extract_data(call, call->buffer, + 11 * sizeof(__be32), false); switch (ret) { case 0: break; case -EAGAIN: return 0; @@ -487,16 +507,9 @@ static int afs_deliver_cb_probe_uuid(struct afs_call *call, struct sk_buff *skb, call->unmarshall++; case 2: - _debug("trailer"); - if (skb->len != 0) - return -EBADMSG; break; } - ret = afs_data_complete(call, skb, last); - if (ret < 0) - return ret; - call->state = AFS_CALL_REPLYING; INIT_WORK(&call->work, SRXAFSCB_ProbeUuid); @@ -570,14 +583,13 @@ static void SRXAFSCB_TellMeAboutYourself(struct work_struct *work) /* * deliver request data to a CB.TellMeAboutYourself call */ -static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *call, - struct sk_buff *skb, bool last) +static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *call) { int ret; - _enter(",{%u},%d", skb->len, last); + _enter(""); - ret = afs_data_complete(call, skb, last); + ret = afs_extract_data(call, NULL, 0, false); if (ret < 0) return ret; -- cgit v1.2.3