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Phonet: fix flawed "SYN/ACK" logic

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* Do not fail if the peer supports more or less than 3 algorithms.
 * Ignore unknown congestion control algorithms instead of failing.
 * Simplify congestion algorithm negotiation (largest is best).
 * Do not use a static buffer.
 * Fix off-by-two read overflow.
 * Avoid extra memory copy (in addition to skb_copy_bits()).

The previous code really made no sense.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rémi Denis-Courmont 2011-02-24 23:15:01 +00:00 committed by David S. Miller
parent 0165d69bcb
commit 8f44fcc72a
2 changed files with 47 additions and 77 deletions
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1
include/net/phonet/pep.h
View File

@ -154,6 +154,7 @@ enum {
PN_LEGACY_FLOW_CONTROL,
PN_ONE_CREDIT_FLOW_CONTROL,
PN_MULTI_CREDIT_FLOW_CONTROL,
PN_MAX_FLOW_CONTROL,
};
#define pn_flow_safe(fc) ((fc) >> 1)

123
net/phonet/pep.c
View File

@ -108,70 +108,6 @@ static int pep_reply(struct sock *sk, struct sk_buff *oskb,
#define PAD 0x00
#ifdef CONFIG_PHONET_PIPECTRLR
static u8 pipe_negotiate_fc(u8 *host_fc, u8 *remote_fc, int len)
{
int i, j;
u8 base_fc, final_fc;
for (i = 0; i < len; i++) {
base_fc = host_fc[i];
for (j = 0; j < len; j++) {
if (remote_fc[j] == base_fc) {
final_fc = base_fc;
goto done;
}
}
}
return -EINVAL;
done:
return final_fc;
}
static int pipe_get_flow_info(struct sock *sk, struct sk_buff *skb,
u8 *pref_rx_fc, u8 *req_tx_fc)
{
struct pnpipehdr *hdr;
u8 n_sb;
if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
return -EINVAL;
hdr = pnp_hdr(skb);
n_sb = hdr->data[4];
__skb_pull(skb, sizeof(*hdr) + 4);
while (n_sb > 0) {
u8 type, buf[3], len = sizeof(buf);
u8 *data = pep_get_sb(skb, &type, &len, buf);
if (data == NULL)
return -EINVAL;
switch (type) {
case PN_PIPE_SB_REQUIRED_FC_TX:
if (len < 3 || (data[2] | data[3] | data[4]) > 3)
break;
req_tx_fc[0] = data[2];
req_tx_fc[1] = data[3];
req_tx_fc[2] = data[4];
break;
case PN_PIPE_SB_PREFERRED_FC_RX:
if (len < 3 || (data[2] | data[3] | data[4]) > 3)
break;
pref_rx_fc[0] = data[2];
pref_rx_fc[1] = data[3];
pref_rx_fc[2] = data[4];
break;
}
n_sb--;
}
return 0;
}
static int pipe_handler_send_req(struct sock *sk, u8 msg_id, gfp_t priority)
{
int len;
@ -661,28 +597,61 @@ static void pipe_destruct(struct sock *sk)
}
#ifdef CONFIG_PHONET_PIPECTRLR
static u8 pipe_negotiate_fc(const u8 *fcs, unsigned n)
{
unsigned i;
u8 final_fc = PN_NO_FLOW_CONTROL;
for (i = 0; i < n; i++) {
u8 fc = fcs[i];
if (fc > final_fc && fc < PN_MAX_FLOW_CONTROL)
final_fc = fc;
}
return final_fc;
}
static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
u8 host_pref_rx_fc[3] = {3, 2, 1}, host_req_tx_fc[3] = {3, 2, 1};
u8 remote_pref_rx_fc[3], remote_req_tx_fc[3];
u8 negotiated_rx_fc, negotiated_tx_fc;
struct pnpipehdr *hdr;
u8 n_sb;
pipe_get_flow_info(sk, skb, remote_pref_rx_fc,
remote_req_tx_fc);
negotiated_tx_fc = pipe_negotiate_fc(remote_req_tx_fc,
host_pref_rx_fc,
sizeof(host_pref_rx_fc));
negotiated_rx_fc = pipe_negotiate_fc(host_req_tx_fc,
remote_pref_rx_fc,
sizeof(host_pref_rx_fc));
if (!pskb_pull(skb, sizeof(*hdr) + 4))
return -EINVAL;
hdr = pnp_hdr(skb);
/* Parse sub-blocks */
n_sb = hdr->data[4];
while (n_sb > 0) {
u8 type, buf[6], len = sizeof(buf);
const u8 *data = pep_get_sb(skb, &type, &len, buf);
if (data == NULL)
return -EINVAL;
switch (type) {
case PN_PIPE_SB_REQUIRED_FC_TX:
if (len < 2 || len < data[0])
break;
pn->tx_fc = pipe_negotiate_fc(data + 2, len - 2);
break;
case PN_PIPE_SB_PREFERRED_FC_RX:
if (len < 2 || len < data[0])
break;
pn->rx_fc = pipe_negotiate_fc(data + 2, len - 2);
break;
}
n_sb--;
}
sk->sk_state = TCP_SYN_RECV;
sk->sk_backlog_rcv = pipe_do_rcv;
sk->sk_destruct = pipe_destruct;
pn->rx_credits = 0;
pn->rx_fc = negotiated_rx_fc;
pn->tx_fc = negotiated_tx_fc;
sk->sk_state_change(sk);
return pipe_handler_send_created_ind(sk, PNS_PIPE_CREATED_IND);