linuxdebug/net/tls/tls_strp.c

634 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Tom Herbert <tom@herbertland.com> */
#include <linux/skbuff.h>
#include <linux/workqueue.h>
#include <net/strparser.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/tls.h>
#include "tls.h"
static struct workqueue_struct *tls_strp_wq;
static void tls_strp_abort_strp(struct tls_strparser *strp, int err)
{
if (strp->stopped)
return;
strp->stopped = 1;
/* Report an error on the lower socket */
WRITE_ONCE(strp->sk->sk_err, -err);
/* Paired with smp_rmb() in tcp_poll() */
smp_wmb();
sk_error_report(strp->sk);
}
static void tls_strp_anchor_free(struct tls_strparser *strp)
{
struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1);
if (!strp->copy_mode)
shinfo->frag_list = NULL;
consume_skb(strp->anchor);
strp->anchor = NULL;
}
static struct sk_buff *
tls_strp_skb_copy(struct tls_strparser *strp, struct sk_buff *in_skb,
int offset, int len)
{
struct sk_buff *skb;
int i, err;
skb = alloc_skb_with_frags(0, len, TLS_PAGE_ORDER,
&err, strp->sk->sk_allocation);
if (!skb)
return NULL;
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
WARN_ON_ONCE(skb_copy_bits(in_skb, offset,
skb_frag_address(frag),
skb_frag_size(frag)));
offset += skb_frag_size(frag);
}
skb->len = len;
skb->data_len = len;
skb_copy_header(skb, in_skb);
return skb;
}
/* Create a new skb with the contents of input copied to its page frags */
static struct sk_buff *tls_strp_msg_make_copy(struct tls_strparser *strp)
{
struct strp_msg *rxm;
struct sk_buff *skb;
skb = tls_strp_skb_copy(strp, strp->anchor, strp->stm.offset,
strp->stm.full_len);
if (!skb)
return NULL;
rxm = strp_msg(skb);
rxm->offset = 0;
return skb;
}
/* Steal the input skb, input msg is invalid after calling this function */
struct sk_buff *tls_strp_msg_detach(struct tls_sw_context_rx *ctx)
{
struct tls_strparser *strp = &ctx->strp;
#ifdef CONFIG_TLS_DEVICE
DEBUG_NET_WARN_ON_ONCE(!strp->anchor->decrypted);
#else
/* This function turns an input into an output,
* that can only happen if we have offload.
*/
WARN_ON(1);
#endif
if (strp->copy_mode) {
struct sk_buff *skb;
/* Replace anchor with an empty skb, this is a little
* dangerous but __tls_cur_msg() warns on empty skbs
* so hopefully we'll catch abuses.
*/
skb = alloc_skb(0, strp->sk->sk_allocation);
if (!skb)
return NULL;
swap(strp->anchor, skb);
return skb;
}
return tls_strp_msg_make_copy(strp);
}
/* Force the input skb to be in copy mode. The data ownership remains
* with the input skb itself (meaning unpause will wipe it) but it can
* be modified.
*/
int tls_strp_msg_cow(struct tls_sw_context_rx *ctx)
{
struct tls_strparser *strp = &ctx->strp;
struct sk_buff *skb;
if (strp->copy_mode)
return 0;
skb = tls_strp_msg_make_copy(strp);
if (!skb)
return -ENOMEM;
tls_strp_anchor_free(strp);
strp->anchor = skb;
tcp_read_done(strp->sk, strp->stm.full_len);
strp->copy_mode = 1;
return 0;
}
/* Make a clone (in the skb sense) of the input msg to keep a reference
* to the underlying data. The reference-holding skbs get placed on
* @dst.
*/
int tls_strp_msg_hold(struct tls_strparser *strp, struct sk_buff_head *dst)
{
struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
if (strp->copy_mode) {
struct sk_buff *skb;
WARN_ON_ONCE(!shinfo->nr_frags);
/* We can't skb_clone() the anchor, it gets wiped by unpause */
skb = alloc_skb(0, strp->sk->sk_allocation);
if (!skb)
return -ENOMEM;
__skb_queue_tail(dst, strp->anchor);
strp->anchor = skb;
} else {
struct sk_buff *iter, *clone;
int chunk, len, offset;
offset = strp->stm.offset;
len = strp->stm.full_len;
iter = shinfo->frag_list;
while (len > 0) {
if (iter->len <= offset) {
offset -= iter->len;
goto next;
}
chunk = iter->len - offset;
offset = 0;
clone = skb_clone(iter, strp->sk->sk_allocation);
if (!clone)
return -ENOMEM;
__skb_queue_tail(dst, clone);
len -= chunk;
next:
iter = iter->next;
}
}
return 0;
}
static void tls_strp_flush_anchor_copy(struct tls_strparser *strp)
{
struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
int i;
DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1);
for (i = 0; i < shinfo->nr_frags; i++)
__skb_frag_unref(&shinfo->frags[i], false);
shinfo->nr_frags = 0;
if (strp->copy_mode) {
kfree_skb_list(shinfo->frag_list);
shinfo->frag_list = NULL;
}
strp->copy_mode = 0;
strp->mixed_decrypted = 0;
}
static int tls_strp_copyin_frag(struct tls_strparser *strp, struct sk_buff *skb,
struct sk_buff *in_skb, unsigned int offset,
size_t in_len)
{
size_t len, chunk;
skb_frag_t *frag;
int sz;
frag = &skb_shinfo(skb)->frags[skb->len / PAGE_SIZE];
len = in_len;
/* First make sure we got the header */
if (!strp->stm.full_len) {
/* Assume one page is more than enough for headers */
chunk = min_t(size_t, len, PAGE_SIZE - skb_frag_size(frag));
WARN_ON_ONCE(skb_copy_bits(in_skb, offset,
skb_frag_address(frag) +
skb_frag_size(frag),
chunk));
skb->len += chunk;
skb->data_len += chunk;
skb_frag_size_add(frag, chunk);
sz = tls_rx_msg_size(strp, skb);
if (sz < 0)
return sz;
/* We may have over-read, sz == 0 is guaranteed under-read */
if (unlikely(sz && sz < skb->len)) {
int over = skb->len - sz;
WARN_ON_ONCE(over > chunk);
skb->len -= over;
skb->data_len -= over;
skb_frag_size_add(frag, -over);
chunk -= over;
}
frag++;
len -= chunk;
offset += chunk;
strp->stm.full_len = sz;
if (!strp->stm.full_len)
goto read_done;
}
/* Load up more data */
while (len && strp->stm.full_len > skb->len) {
chunk = min_t(size_t, len, strp->stm.full_len - skb->len);
chunk = min_t(size_t, chunk, PAGE_SIZE - skb_frag_size(frag));
WARN_ON_ONCE(skb_copy_bits(in_skb, offset,
skb_frag_address(frag) +
skb_frag_size(frag),
chunk));
skb->len += chunk;
skb->data_len += chunk;
skb_frag_size_add(frag, chunk);
frag++;
len -= chunk;
offset += chunk;
}
read_done:
return in_len - len;
}
static int tls_strp_copyin_skb(struct tls_strparser *strp, struct sk_buff *skb,
struct sk_buff *in_skb, unsigned int offset,
size_t in_len)
{
struct sk_buff *nskb, *first, *last;
struct skb_shared_info *shinfo;
size_t chunk;
int sz;
if (strp->stm.full_len)
chunk = strp->stm.full_len - skb->len;
else
chunk = TLS_MAX_PAYLOAD_SIZE + PAGE_SIZE;
chunk = min(chunk, in_len);
nskb = tls_strp_skb_copy(strp, in_skb, offset, chunk);
if (!nskb)
return -ENOMEM;
shinfo = skb_shinfo(skb);
if (!shinfo->frag_list) {
shinfo->frag_list = nskb;
nskb->prev = nskb;
} else {
first = shinfo->frag_list;
last = first->prev;
last->next = nskb;
first->prev = nskb;
}
skb->len += chunk;
skb->data_len += chunk;
if (!strp->stm.full_len) {
sz = tls_rx_msg_size(strp, skb);
if (sz < 0)
return sz;
/* We may have over-read, sz == 0 is guaranteed under-read */
if (unlikely(sz && sz < skb->len)) {
int over = skb->len - sz;
WARN_ON_ONCE(over > chunk);
skb->len -= over;
skb->data_len -= over;
__pskb_trim(nskb, nskb->len - over);
chunk -= over;
}
strp->stm.full_len = sz;
}
return chunk;
}
static int tls_strp_copyin(read_descriptor_t *desc, struct sk_buff *in_skb,
unsigned int offset, size_t in_len)
{
struct tls_strparser *strp = (struct tls_strparser *)desc->arg.data;
struct sk_buff *skb;
int ret;
if (strp->msg_ready)
return 0;
skb = strp->anchor;
if (!skb->len)
skb_copy_decrypted(skb, in_skb);
else
strp->mixed_decrypted |= !!skb_cmp_decrypted(skb, in_skb);
if (IS_ENABLED(CONFIG_TLS_DEVICE) && strp->mixed_decrypted)
ret = tls_strp_copyin_skb(strp, skb, in_skb, offset, in_len);
else
ret = tls_strp_copyin_frag(strp, skb, in_skb, offset, in_len);
if (ret < 0) {
desc->error = ret;
ret = 0;
}
if (strp->stm.full_len && strp->stm.full_len == skb->len) {
desc->count = 0;
strp->msg_ready = 1;
tls_rx_msg_ready(strp);
}
return ret;
}
static int tls_strp_read_copyin(struct tls_strparser *strp)
{
struct socket *sock = strp->sk->sk_socket;
read_descriptor_t desc;
desc.arg.data = strp;
desc.error = 0;
desc.count = 1; /* give more than one skb per call */
/* sk should be locked here, so okay to do read_sock */
sock->ops->read_sock(strp->sk, &desc, tls_strp_copyin);
return desc.error;
}
static int tls_strp_read_copy(struct tls_strparser *strp, bool qshort)
{
struct skb_shared_info *shinfo;
struct page *page;
int need_spc, len;
/* If the rbuf is small or rcv window has collapsed to 0 we need
* to read the data out. Otherwise the connection will stall.
* Without pressure threshold of INT_MAX will never be ready.
*/
if (likely(qshort && !tcp_epollin_ready(strp->sk, INT_MAX)))
return 0;
shinfo = skb_shinfo(strp->anchor);
shinfo->frag_list = NULL;
/* If we don't know the length go max plus page for cipher overhead */
need_spc = strp->stm.full_len ?: TLS_MAX_PAYLOAD_SIZE + PAGE_SIZE;
for (len = need_spc; len > 0; len -= PAGE_SIZE) {
page = alloc_page(strp->sk->sk_allocation);
if (!page) {
tls_strp_flush_anchor_copy(strp);
return -ENOMEM;
}
skb_fill_page_desc(strp->anchor, shinfo->nr_frags++,
page, 0, 0);
}
strp->copy_mode = 1;
strp->stm.offset = 0;
strp->anchor->len = 0;
strp->anchor->data_len = 0;
strp->anchor->truesize = round_up(need_spc, PAGE_SIZE);
tls_strp_read_copyin(strp);
return 0;
}
static bool tls_strp_check_queue_ok(struct tls_strparser *strp)
{
unsigned int len = strp->stm.offset + strp->stm.full_len;
struct sk_buff *first, *skb;
u32 seq;
first = skb_shinfo(strp->anchor)->frag_list;
skb = first;
seq = TCP_SKB_CB(first)->seq;
/* Make sure there's no duplicate data in the queue,
* and the decrypted status matches.
*/
while (skb->len < len) {
seq += skb->len;
len -= skb->len;
skb = skb->next;
if (TCP_SKB_CB(skb)->seq != seq)
return false;
if (skb_cmp_decrypted(first, skb))
return false;
}
return true;
}
static void tls_strp_load_anchor_with_queue(struct tls_strparser *strp, int len)
{
struct tcp_sock *tp = tcp_sk(strp->sk);
struct sk_buff *first;
u32 offset;
first = tcp_recv_skb(strp->sk, tp->copied_seq, &offset);
if (WARN_ON_ONCE(!first))
return;
/* Bestow the state onto the anchor */
strp->anchor->len = offset + len;
strp->anchor->data_len = offset + len;
strp->anchor->truesize = offset + len;
skb_shinfo(strp->anchor)->frag_list = first;
skb_copy_header(strp->anchor, first);
strp->anchor->destructor = NULL;
strp->stm.offset = offset;
}
void tls_strp_msg_load(struct tls_strparser *strp, bool force_refresh)
{
struct strp_msg *rxm;
struct tls_msg *tlm;
DEBUG_NET_WARN_ON_ONCE(!strp->msg_ready);
DEBUG_NET_WARN_ON_ONCE(!strp->stm.full_len);
if (!strp->copy_mode && force_refresh) {
if (WARN_ON(tcp_inq(strp->sk) < strp->stm.full_len))
return;
tls_strp_load_anchor_with_queue(strp, strp->stm.full_len);
}
rxm = strp_msg(strp->anchor);
rxm->full_len = strp->stm.full_len;
rxm->offset = strp->stm.offset;
tlm = tls_msg(strp->anchor);
tlm->control = strp->mark;
}
/* Called with lock held on lower socket */
static int tls_strp_read_sock(struct tls_strparser *strp)
{
int sz, inq;
inq = tcp_inq(strp->sk);
if (inq < 1)
return 0;
if (unlikely(strp->copy_mode))
return tls_strp_read_copyin(strp);
if (inq < strp->stm.full_len)
return tls_strp_read_copy(strp, true);
if (!strp->stm.full_len) {
tls_strp_load_anchor_with_queue(strp, inq);
sz = tls_rx_msg_size(strp, strp->anchor);
if (sz < 0) {
tls_strp_abort_strp(strp, sz);
return sz;
}
strp->stm.full_len = sz;
if (!strp->stm.full_len || inq < strp->stm.full_len)
return tls_strp_read_copy(strp, true);
}
if (!tls_strp_check_queue_ok(strp))
return tls_strp_read_copy(strp, false);
strp->msg_ready = 1;
tls_rx_msg_ready(strp);
return 0;
}
void tls_strp_check_rcv(struct tls_strparser *strp)
{
if (unlikely(strp->stopped) || strp->msg_ready)
return;
if (tls_strp_read_sock(strp) == -ENOMEM)
queue_work(tls_strp_wq, &strp->work);
}
/* Lower sock lock held */
void tls_strp_data_ready(struct tls_strparser *strp)
{
/* This check is needed to synchronize with do_tls_strp_work.
* do_tls_strp_work acquires a process lock (lock_sock) whereas
* the lock held here is bh_lock_sock. The two locks can be
* held by different threads at the same time, but bh_lock_sock
* allows a thread in BH context to safely check if the process
* lock is held. In this case, if the lock is held, queue work.
*/
if (sock_owned_by_user_nocheck(strp->sk)) {
queue_work(tls_strp_wq, &strp->work);
return;
}
tls_strp_check_rcv(strp);
}
static void tls_strp_work(struct work_struct *w)
{
struct tls_strparser *strp =
container_of(w, struct tls_strparser, work);
lock_sock(strp->sk);
tls_strp_check_rcv(strp);
release_sock(strp->sk);
}
void tls_strp_msg_done(struct tls_strparser *strp)
{
WARN_ON(!strp->stm.full_len);
if (likely(!strp->copy_mode))
tcp_read_done(strp->sk, strp->stm.full_len);
else
tls_strp_flush_anchor_copy(strp);
strp->msg_ready = 0;
memset(&strp->stm, 0, sizeof(strp->stm));
tls_strp_check_rcv(strp);
}
void tls_strp_stop(struct tls_strparser *strp)
{
strp->stopped = 1;
}
int tls_strp_init(struct tls_strparser *strp, struct sock *sk)
{
memset(strp, 0, sizeof(*strp));
strp->sk = sk;
strp->anchor = alloc_skb(0, GFP_KERNEL);
if (!strp->anchor)
return -ENOMEM;
INIT_WORK(&strp->work, tls_strp_work);
return 0;
}
/* strp must already be stopped so that tls_strp_recv will no longer be called.
* Note that tls_strp_done is not called with the lower socket held.
*/
void tls_strp_done(struct tls_strparser *strp)
{
WARN_ON(!strp->stopped);
cancel_work_sync(&strp->work);
tls_strp_anchor_free(strp);
}
int __init tls_strp_dev_init(void)
{
tls_strp_wq = create_workqueue("tls-strp");
if (unlikely(!tls_strp_wq))
return -ENOMEM;
return 0;
}
void tls_strp_dev_exit(void)
{
destroy_workqueue(tls_strp_wq);
}