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bcmserver: main(): convert from sprintf() to snprintf() to avoid buffer overflow 

Message-ID: <DM6PR17MB28748DA25E52E1BD3EC593E6937AA@DM6PR17MB2874.namprd17.prod.outlook.com>
pull/625/head
Marc Kleine-Budde 2026-03-09 16:50:10 +01:00
parent 44e6eb45e3
commit 3cae8a449b
1 changed files with 28 additions and 8 deletions
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34
bcmserver.c
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@ -234,7 +234,7 @@ int main(void)
}
while (1) {
again:
FD_ZERO(&readfds);
FD_SET(sc, &readfds);
FD_SET(sa, &readfds);
@ -242,6 +242,8 @@ int main(void)
select((sc > sa)?sc+1:sa+1, &readfds, NULL, NULL, NULL);
if (FD_ISSET(sc, &readfds)) {
size_t size = sizeof(rxmsg);
int len = 0, res;
recvfrom(sc, &msg, sizeof(msg), 0,
(struct sockaddr*)&caddr, &caddrlen);
@ -249,17 +251,35 @@ int main(void)
ifr.ifr_ifindex = caddr.can_ifindex;
ioctl(sc, SIOCGIFNAME, &ifr);
sprintf(rxmsg, "< %s %03X %d ", ifr.ifr_name,
res = snprintf(rxmsg, size, "< %s %03X %d ", ifr.ifr_name,
msg.msg_head.can_id, msg.frame.can_dlc);
if (res < 0 || (size_t)res >= size) {
printf("Error: rxmsg buffer (size %zu) too small for data.\n", size);
continue;
}
for ( i = 0; i < msg.frame.can_dlc; i++)
sprintf(rxmsg + strlen(rxmsg), "%02X ",
msg.frame.data[i]);
len += res;
for (i = 0; i < msg.frame.can_dlc; i++) {
res = snprintf(rxmsg + len, size - len, "%02X ", msg.frame.data[i]);
if (res < 0 || (size_t)res >= (size - len)) {
printf("Error: rxmsg buffer (size %zu) too small for data.\n", size);
goto again;
}
len += res;
}
/* delimiter '\0' for Adobe(TM) Flash(TM) XML sockets */
strcat(rxmsg, ">\0");
res = snprintf(rxmsg + len, size - len, ">");
if (res < 0 || (size_t)res >= (size - len)) {
printf("Error: rxmsg buffer (size %zu) too small for data.\n", size);
continue;
}
send(sa, rxmsg, strlen(rxmsg) + 1, 0);
len += res;
send(sa, rxmsg, len + 1, 0);
}