Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[Backport] asymcute: fix one byte out-of-bounds access in _len_get #18453

Merged
merged 1 commit into from
Aug 15, 2022
Merged

[Backport] asymcute: fix one byte out-of-bounds access in _len_get #18453

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 14 additions & 4 deletions sys/net/application_layer/asymcute/asymcute.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -83,13 +83,16 @@ static size_t _len_set(uint8_t *buf, size_t len)
}
}

static size_t _len_get(uint8_t *buf, size_t *len)
static ssize_t _len_get(uint8_t *buf, size_t pkt_len, size_t *len)
{
if (buf[0] != 0x01) {
*len = (uint16_t)buf[0];
return 1;
}
else {
if (pkt_len < 3) {
return -1;
}
*len = byteorder_bebuftohs(&buf[1]);
return 3;
}
Expand All @@ -107,8 +110,10 @@ static uint16_t _msg_id_next(asymcute_con_t *con)
static uint8_t _req_type(asymcute_req_t *req)
{
size_t len;
size_t pos = _len_get(req->data, &len);
return req->data[pos];
ssize_t pos = _len_get(req->data, req->data_len, &len);
/* requests are created by us and should thus always be valid */
assert(pos != -1 && (size_t)pos < req->data_len);
return req->data[(size_t)pos];
}

/* @pre con is locked */
Expand Down Expand Up @@ -590,7 +595,12 @@ void _on_pkt(sock_udp_t *sock, sock_async_flags_t type, void *arg)
CONFIG_ASYMCUTE_BUFSIZE, 0, NULL);
if (pkt_len >= MIN_PKT_LEN) {
size_t len;
size_t pos = _len_get(con->rxbuf, &len);
ssize_t lret = _len_get(con->rxbuf, pkt_len, &len);
if (lret == -1) {
/* first octet was 0x01 but pkt does not have more than 3 octets */
return;
}
size_t pos = (size_t)lret;

/* validate incoming data: verify message length */
if (((size_t)pkt_len <= pos) || ((size_t)pkt_len < len)) {
Expand Down