From 96aec9a5e95ba9dde57b84576b8541f3a111209c Mon Sep 17 00:00:00 2001 From: Conrad Meyer Date: Thu, 12 May 2016 03:37:17 +0000 Subject: [PATCH] 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 --- usr.sbin/rtadvd/control.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/usr.sbin/rtadvd/control.c b/usr.sbin/rtadvd/control.c index 5e4a68b5bbb6..fc6d53658f6f 100644 --- a/usr.sbin/rtadvd/control.c +++ b/usr.sbin/rtadvd/control.c @@ -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;