Author: cem
Date: Thu May 12 03:37:17 2016
New Revision: 299507
URL: https://svnweb.freebsd.org/changeset/base/299507
Log:
rtadvd(8): Fix a typo in full msg receive logic
Check against the size of the struct, not the pointer. Previously, a message
with a cm_len between 9 and 23 (inclusive) could cause int msglen to underflow
and read(2) to be invoked with msglen size (implicitly cast to signed),
overrunning the caller-provided buffer.
All users of cm_recv() supply a stack buffer.
On the other hand, the rtadvd control socket appears to only be writable by
the
owner, who is probably root.
While here, correct some types to be size_t or ssize_t.
Reported by: Coverity
CID: 1008477
Security: unix socket remotes may overflow stack in rtadvd
Sponsored by: EMC / Isilon Storage Division
Modified:
head/usr.sbin/rtadvd/control.c
Modified: head/usr.sbin/rtadvd/control.c
==============================================================================
--- head/usr.sbin/rtadvd/control.c Thu May 12 03:36:49 2016
(r299506)
+++ head/usr.sbin/rtadvd/control.c Thu May 12 03:37:17 2016
(r299507)
@@ -59,7 +59,7 @@
int
cm_recv(int fd, char *buf)
{
- int n;
+ ssize_t n;
struct ctrl_msg_hdr *cm;
char *msg;
struct pollfd pfds[1];
@@ -98,7 +98,7 @@ cm_recv(int fd, char *buf)
}
}
- if (n != sizeof(*cm)) {
+ if (n != (ssize_t)sizeof(*cm)) {
syslog(LOG_WARNING,
"<%s> received a too small message.", __func__);
goto cm_recv_err;
@@ -123,11 +123,11 @@ cm_recv(int fd, char *buf)
"<%s> ctrl msg received: type=%d", __func__,
cm->cm_type);
- if (cm->cm_len > sizeof(cm)) {
- int msglen = cm->cm_len - sizeof(*cm);
+ if (cm->cm_len > sizeof(*cm)) {
+ size_t msglen = cm->cm_len - sizeof(*cm);
syslog(LOG_DEBUG,
- "<%s> ctrl msg has payload (len=%d)", __func__,
+ "<%s> ctrl msg has payload (len=%zu)", __func__,
msglen);
for (;;) {
@@ -153,7 +153,7 @@ cm_recv(int fd, char *buf)
}
break;
}
- if (n != msglen) {
+ if (n != (ssize_t)msglen) {
syslog(LOG_WARNING,
"<%s> payload size mismatch.", __func__);
goto cm_recv_err;
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