From 987db9f7cd1e77e611b770a569068c43949aa6fd Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 19 Aug 2019 09:25:38 +0100 Subject: rxrpc: Use the tx-phase skb flag to simplify tracing Use the previously-added transmit-phase skbuff private flag to simplify the socket buffer tracing a bit. Which phase the skbuff comes from can now be divined from the skb rather than having to be guessed from the call state. We can also reduce the number of rxrpc_skb_trace values by eliminating the difference between Tx and Rx in the symbols. Signed-off-by: David Howells --- include/trace/events/rxrpc.h | 51 +++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 29 deletions(-) (limited to 'include') diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index fa06b528c73c..e2356c51883b 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -23,20 +23,15 @@ #define __RXRPC_DECLARE_TRACE_ENUMS_ONCE_ONLY enum rxrpc_skb_trace { - rxrpc_skb_rx_cleaned, - rxrpc_skb_rx_freed, - rxrpc_skb_rx_got, - rxrpc_skb_rx_lost, - rxrpc_skb_rx_purged, - rxrpc_skb_rx_received, - rxrpc_skb_rx_rotated, - rxrpc_skb_rx_seen, - rxrpc_skb_tx_cleaned, - rxrpc_skb_tx_freed, - rxrpc_skb_tx_got, - rxrpc_skb_tx_new, - rxrpc_skb_tx_rotated, - rxrpc_skb_tx_seen, + rxrpc_skb_cleaned, + rxrpc_skb_freed, + rxrpc_skb_got, + rxrpc_skb_lost, + rxrpc_skb_new, + rxrpc_skb_purged, + rxrpc_skb_received, + rxrpc_skb_rotated, + rxrpc_skb_seen, }; enum rxrpc_local_trace { @@ -228,20 +223,15 @@ enum rxrpc_tx_point { * Declare tracing information enums and their string mappings for display. */ #define rxrpc_skb_traces \ - EM(rxrpc_skb_rx_cleaned, "Rx CLN") \ - EM(rxrpc_skb_rx_freed, "Rx FRE") \ - EM(rxrpc_skb_rx_got, "Rx GOT") \ - EM(rxrpc_skb_rx_lost, "Rx *L*") \ - EM(rxrpc_skb_rx_purged, "Rx PUR") \ - EM(rxrpc_skb_rx_received, "Rx RCV") \ - EM(rxrpc_skb_rx_rotated, "Rx ROT") \ - EM(rxrpc_skb_rx_seen, "Rx SEE") \ - EM(rxrpc_skb_tx_cleaned, "Tx CLN") \ - EM(rxrpc_skb_tx_freed, "Tx FRE") \ - EM(rxrpc_skb_tx_got, "Tx GOT") \ - EM(rxrpc_skb_tx_new, "Tx NEW") \ - EM(rxrpc_skb_tx_rotated, "Tx ROT") \ - E_(rxrpc_skb_tx_seen, "Tx SEE") + EM(rxrpc_skb_cleaned, "CLN") \ + EM(rxrpc_skb_freed, "FRE") \ + EM(rxrpc_skb_got, "GOT") \ + EM(rxrpc_skb_lost, "*L*") \ + EM(rxrpc_skb_new, "NEW") \ + EM(rxrpc_skb_purged, "PUR") \ + EM(rxrpc_skb_received, "RCV") \ + EM(rxrpc_skb_rotated, "ROT") \ + E_(rxrpc_skb_seen, "SEE") #define rxrpc_local_traces \ EM(rxrpc_local_got, "GOT") \ @@ -650,6 +640,7 @@ TRACE_EVENT(rxrpc_skb, TP_STRUCT__entry( __field(struct sk_buff *, skb ) __field(enum rxrpc_skb_trace, op ) + __field(u8, flags ) __field(int, usage ) __field(int, mod_count ) __field(const void *, where ) @@ -657,14 +648,16 @@ TRACE_EVENT(rxrpc_skb, TP_fast_assign( __entry->skb = skb; + __entry->flags = rxrpc_skb(skb)->rx_flags; __entry->op = op; __entry->usage = usage; __entry->mod_count = mod_count; __entry->where = where; ), - TP_printk("s=%p %s u=%d m=%d p=%pSR", + TP_printk("s=%p %cx %s u=%d m=%d p=%pSR", __entry->skb, + __entry->flags & RXRPC_SKB_TX_BUFFER ? 'T' : 'R', __print_symbolic(__entry->op, rxrpc_skb_traces), __entry->usage, __entry->mod_count, -- cgit v1.2.3 From d0d5c0cd1e711c98703f3544c1e6fc1372898de5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 27 Aug 2019 10:13:46 +0100 Subject: rxrpc: Use skb_unshare() rather than skb_cow_data() The in-place decryption routines in AF_RXRPC's rxkad security module currently call skb_cow_data() to make sure the data isn't shared and that the skb can be written over. This has a problem, however, as the softirq handler may be still holding a ref or the Rx ring may be holding multiple refs when skb_cow_data() is called in rxkad_verify_packet() - and so skb_shared() returns true and __pskb_pull_tail() dislikes that. If this occurs, something like the following report will be generated. kernel BUG at net/core/skbuff.c:1463! ... RIP: 0010:pskb_expand_head+0x253/0x2b0 ... Call Trace: __pskb_pull_tail+0x49/0x460 skb_cow_data+0x6f/0x300 rxkad_verify_packet+0x18b/0xb10 [rxrpc] rxrpc_recvmsg_data.isra.11+0x4a8/0xa10 [rxrpc] rxrpc_kernel_recv_data+0x126/0x240 [rxrpc] afs_extract_data+0x51/0x2d0 [kafs] afs_deliver_fs_fetch_data+0x188/0x400 [kafs] afs_deliver_to_call+0xac/0x430 [kafs] afs_wait_for_call_to_complete+0x22f/0x3d0 [kafs] afs_make_call+0x282/0x3f0 [kafs] afs_fs_fetch_data+0x164/0x300 [kafs] afs_fetch_data+0x54/0x130 [kafs] afs_readpages+0x20d/0x340 [kafs] read_pages+0x66/0x180 __do_page_cache_readahead+0x188/0x1a0 ondemand_readahead+0x17d/0x2e0 generic_file_read_iter+0x740/0xc10 __vfs_read+0x145/0x1a0 vfs_read+0x8c/0x140 ksys_read+0x4a/0xb0 do_syscall_64+0x43/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by using skb_unshare() instead in the input path for DATA packets that have a security index != 0. Non-DATA packets don't need in-place encryption and neither do unencrypted DATA packets. Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code") Reported-by: Julian Wollrath Signed-off-by: David Howells --- include/trace/events/rxrpc.h | 12 ++++++++---- net/rxrpc/ar-internal.h | 1 + net/rxrpc/input.c | 18 ++++++++++++++++++ net/rxrpc/rxkad.c | 32 +++++++++----------------------- net/rxrpc/skbuff.c | 25 ++++++++++++++++++++----- 5 files changed, 56 insertions(+), 32 deletions(-) (limited to 'include') diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index e2356c51883b..a13a62db3565 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -32,6 +32,8 @@ enum rxrpc_skb_trace { rxrpc_skb_received, rxrpc_skb_rotated, rxrpc_skb_seen, + rxrpc_skb_unshared, + rxrpc_skb_unshared_nomem, }; enum rxrpc_local_trace { @@ -231,7 +233,9 @@ enum rxrpc_tx_point { EM(rxrpc_skb_purged, "PUR") \ EM(rxrpc_skb_received, "RCV") \ EM(rxrpc_skb_rotated, "ROT") \ - E_(rxrpc_skb_seen, "SEE") + EM(rxrpc_skb_seen, "SEE") \ + EM(rxrpc_skb_unshared, "UNS") \ + E_(rxrpc_skb_unshared_nomem, "US0") #define rxrpc_local_traces \ EM(rxrpc_local_got, "GOT") \ @@ -633,9 +637,9 @@ TRACE_EVENT(rxrpc_call, TRACE_EVENT(rxrpc_skb, TP_PROTO(struct sk_buff *skb, enum rxrpc_skb_trace op, - int usage, int mod_count, const void *where), + int usage, int mod_count, u8 flags, const void *where), - TP_ARGS(skb, op, usage, mod_count, where), + TP_ARGS(skb, op, usage, mod_count, flags, where), TP_STRUCT__entry( __field(struct sk_buff *, skb ) @@ -648,7 +652,7 @@ TRACE_EVENT(rxrpc_skb, TP_fast_assign( __entry->skb = skb; - __entry->flags = rxrpc_skb(skb)->rx_flags; + __entry->flags = flags; __entry->op = op; __entry->usage = usage; __entry->mod_count = mod_count; diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 2d5294f3e62f..852e58781fda 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1110,6 +1110,7 @@ void rxrpc_kernel_data_consumed(struct rxrpc_call *, struct sk_buff *); void rxrpc_packet_destructor(struct sk_buff *); void rxrpc_new_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_see_skb(struct sk_buff *, enum rxrpc_skb_trace); +void rxrpc_eaten_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_get_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_free_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_purge_queue(struct sk_buff_head *); diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 31090bdf1fae..d122c53c8697 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -1249,6 +1249,24 @@ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb) goto bad_message; if (!rxrpc_validate_data(skb)) goto bad_message; + + /* Unshare the packet so that it can be modified for in-place + * decryption. + */ + if (sp->hdr.securityIndex != 0) { + struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC); + if (!nskb) { + rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem); + goto out; + } + + if (nskb != skb) { + rxrpc_eaten_skb(skb, rxrpc_skb_received); + rxrpc_new_skb(skb, rxrpc_skb_unshared); + skb = nskb; + sp = rxrpc_skb(skb); + } + } break; case RXRPC_PACKET_TYPE_CHALLENGE: diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c index ae8cd8926456..c60c520fde7c 100644 --- a/net/rxrpc/rxkad.c +++ b/net/rxrpc/rxkad.c @@ -187,10 +187,8 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, struct rxrpc_skb_priv *sp; struct rxrpc_crypt iv; struct scatterlist sg[16]; - struct sk_buff *trailer; unsigned int len; u16 check; - int nsg; int err; sp = rxrpc_skb(skb); @@ -214,15 +212,14 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, crypto_skcipher_encrypt(req); /* we want to encrypt the skbuff in-place */ - nsg = skb_cow_data(skb, 0, &trailer); - err = -ENOMEM; - if (nsg < 0 || nsg > 16) + err = -EMSGSIZE; + if (skb_shinfo(skb)->nr_frags > 16) goto out; len = data_size + call->conn->size_align - 1; len &= ~(call->conn->size_align - 1); - sg_init_table(sg, nsg); + sg_init_table(sg, ARRAY_SIZE(sg)); err = skb_to_sgvec(skb, sg, 0, len); if (unlikely(err < 0)) goto out; @@ -319,11 +316,10 @@ static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb, struct rxkad_level1_hdr sechdr; struct rxrpc_crypt iv; struct scatterlist sg[16]; - struct sk_buff *trailer; bool aborted; u32 data_size, buf; u16 check; - int nsg, ret; + int ret; _enter(""); @@ -336,11 +332,7 @@ static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb, /* Decrypt the skbuff in-place. TODO: We really want to decrypt * directly into the target buffer. */ - nsg = skb_cow_data(skb, 0, &trailer); - if (nsg < 0 || nsg > 16) - goto nomem; - - sg_init_table(sg, nsg); + sg_init_table(sg, ARRAY_SIZE(sg)); ret = skb_to_sgvec(skb, sg, offset, 8); if (unlikely(ret < 0)) return ret; @@ -388,10 +380,6 @@ protocol_error: if (aborted) rxrpc_send_abort_packet(call); return -EPROTO; - -nomem: - _leave(" = -ENOMEM"); - return -ENOMEM; } /* @@ -406,7 +394,6 @@ static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb, struct rxkad_level2_hdr sechdr; struct rxrpc_crypt iv; struct scatterlist _sg[4], *sg; - struct sk_buff *trailer; bool aborted; u32 data_size, buf; u16 check; @@ -423,12 +410,11 @@ static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb, /* Decrypt the skbuff in-place. TODO: We really want to decrypt * directly into the target buffer. */ - nsg = skb_cow_data(skb, 0, &trailer); - if (nsg < 0) - goto nomem; - sg = _sg; - if (unlikely(nsg > 4)) { + nsg = skb_shinfo(skb)->nr_frags; + if (nsg <= 4) { + nsg = 4; + } else { sg = kmalloc_array(nsg, sizeof(*sg), GFP_NOIO); if (!sg) goto nomem; diff --git a/net/rxrpc/skbuff.c b/net/rxrpc/skbuff.c index 8e6f45f84b9b..0348d2bf6f7d 100644 --- a/net/rxrpc/skbuff.c +++ b/net/rxrpc/skbuff.c @@ -24,7 +24,8 @@ void rxrpc_new_skb(struct sk_buff *skb, enum rxrpc_skb_trace op) { const void *here = __builtin_return_address(0); int n = atomic_inc_return(select_skb_count(skb)); - trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, here); + trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, + rxrpc_skb(skb)->rx_flags, here); } /* @@ -35,7 +36,8 @@ void rxrpc_see_skb(struct sk_buff *skb, enum rxrpc_skb_trace op) const void *here = __builtin_return_address(0); if (skb) { int n = atomic_read(select_skb_count(skb)); - trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, here); + trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, + rxrpc_skb(skb)->rx_flags, here); } } @@ -46,10 +48,21 @@ void rxrpc_get_skb(struct sk_buff *skb, enum rxrpc_skb_trace op) { const void *here = __builtin_return_address(0); int n = atomic_inc_return(select_skb_count(skb)); - trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, here); + trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, + rxrpc_skb(skb)->rx_flags, here); skb_get(skb); } +/* + * Note the dropping of a ref on a socket buffer by the core. + */ +void rxrpc_eaten_skb(struct sk_buff *skb, enum rxrpc_skb_trace op) +{ + const void *here = __builtin_return_address(0); + int n = atomic_inc_return(&rxrpc_n_rx_skbs); + trace_rxrpc_skb(skb, op, 0, n, 0, here); +} + /* * Note the destruction of a socket buffer. */ @@ -60,7 +73,8 @@ void rxrpc_free_skb(struct sk_buff *skb, enum rxrpc_skb_trace op) int n; CHECK_SLAB_OKAY(&skb->users); n = atomic_dec_return(select_skb_count(skb)); - trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, here); + trace_rxrpc_skb(skb, op, refcount_read(&skb->users), n, + rxrpc_skb(skb)->rx_flags, here); kfree_skb(skb); } } @@ -75,7 +89,8 @@ void rxrpc_purge_queue(struct sk_buff_head *list) while ((skb = skb_dequeue((list))) != NULL) { int n = atomic_dec_return(select_skb_count(skb)); trace_rxrpc_skb(skb, rxrpc_skb_purged, - refcount_read(&skb->users), n, here); + refcount_read(&skb->users), n, + rxrpc_skb(skb)->rx_flags, here); kfree_skb(skb); } } -- cgit v1.2.3