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net: tcp2: Fix reading TCP options

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This patch fixes an issue with TCP options reading. Previous approach
was accessing the options with pointers (th + 1). This does not work if
TCP options span multiple net_pkt buffer fragments. Instead net_pkt
functions must be used.

Signed-off-by: Ruslan Mstoi <ruslan.mstoi@intel.com>
This commit is contained in:
Ruslan Mstoi 2020-04-16 18:54:28 +03:00 • committed by Jukka Rissanen
commit 59c21ad3cf
1 changed files with 20 additions and 5 deletions
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25
subsys/net/ip/tcp2.c
View file

@ -361,10 +361,26 @@ static const char *tcp_conn_state(struct tcp *conn, struct net_pkt *pkt)
return buf; return buf;
} }
static bool tcp_options_check(void *buf, ssize_t len) static u8_t *tcp_options_get(struct net_pkt *pkt, int tcp_options_len)
{
static u8_t options[40]; /* TCP header max options size is 40 */
struct net_pkt_cursor backup;
net_pkt_cursor_backup(pkt, &backup);
net_pkt_cursor_init(pkt);
net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) + net_pkt_ip_opts_len(pkt) +
sizeof(struct tcphdr));
net_pkt_read(pkt, options, tcp_options_len);
net_pkt_cursor_restore(pkt, &backup);
return options;
}
static bool tcp_options_check(struct net_pkt *pkt, ssize_t len)
{ {
bool result = len > 0 && ((len % 4) == 0) ? true : false; bool result = len > 0 && ((len % 4) == 0) ? true : false;
u8_t *options = buf, opt, opt_len; u8_t *options = tcp_options_get(pkt, len);
u8_t opt, opt_len;
NET_DBG("len=%zd", len); NET_DBG("len=%zd", len);
@ -424,8 +440,7 @@ static size_t tcp_data_len(struct net_pkt *pkt)
ssize_t len = net_pkt_get_len(pkt) - net_pkt_ip_hdr_len(pkt) - ssize_t len = net_pkt_get_len(pkt) - net_pkt_ip_hdr_len(pkt) -
net_pkt_ip_opts_len(pkt) - sizeof(*th) - tcp_options_len; net_pkt_ip_opts_len(pkt) - sizeof(*th) - tcp_options_len;
if (tcp_options_len && tcp_options_check((th + 1), tcp_options_len) if (tcp_options_len && !tcp_options_check(pkt, tcp_options_len)) {
== false) {
len = 0; len = 0;
} }
@ -846,7 +861,7 @@ static void tcp_in(struct tcp *conn, struct net_pkt *pkt)
goto next_state; goto next_state;
} }
if (tcp_options_len && !tcp_options_check((th + 1), tcp_options_len)) { if (tcp_options_len && !tcp_options_check(pkt, tcp_options_len)) {
NET_DBG("DROP: Invalid TCP option list"); NET_DBG("DROP: Invalid TCP option list");
tcp_out(conn, RST); tcp_out(conn, RST);
conn_state(conn, TCP_CLOSED); conn_state(conn, TCP_CLOSED);