Date: Tue, 17 Jan 2017 03:52:57 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r312331 - head/contrib/bsnmp/snmpd Message-ID: <201701170352.v0H3qvNJ025187@repo.freebsd.org>
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Author: glebius Date: Tue Jan 17 03:52:57 2017 New Revision: 312331 URL: https://svnweb.freebsd.org/changeset/base/312331 Log: Fix regression from r310655, which broke operation of bsnmpd if it is bound to a non-wildcard address. As documented in ip(4), doing sendmsg(2) with IP_SENDSRCADDR on a socket that is bound to non-wildcard address is completely different to using this control message on a wildcard one. A fix is to add a bool to mark whether we did setsockopt(IP_RECVDSTADDR) on the socket, and use IP_SENDSRCADDR control message only if we did. While here, garbage collect absolutely useless udp_recv() function that establishes some structures on stack to never use them later. Modified: head/contrib/bsnmp/snmpd/trans_udp.c head/contrib/bsnmp/snmpd/trans_udp.h Modified: head/contrib/bsnmp/snmpd/trans_udp.c ============================================================================== --- head/contrib/bsnmp/snmpd/trans_udp.c Tue Jan 17 03:44:45 2017 (r312330) +++ head/contrib/bsnmp/snmpd/trans_udp.c Tue Jan 17 03:52:57 2017 (r312331) @@ -34,6 +34,7 @@ #include <sys/queue.h> #include <sys/ucred.h> +#include <stdbool.h> #include <stdlib.h> #include <syslog.h> #include <string.h> @@ -119,13 +120,15 @@ udp_init_port(struct tport *tp) addr.sin_port = htons(p->port); addr.sin_family = AF_INET; addr.sin_len = sizeof(addr); - if (addr.sin_addr.s_addr == INADDR_ANY && - setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on, - sizeof(on)) == -1) { - syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m"); - close(p->input.fd); - p->input.fd = -1; - return (SNMP_ERR_GENERR); + if (addr.sin_addr.s_addr == INADDR_ANY) { + if (setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on, + sizeof(on)) == -1) { + syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m"); + close(p->input.fd); + p->input.fd = -1; + return (SNMP_ERR_GENERR); + } + p->recvdstaddr = true; } if (bind(p->input.fd, (struct sockaddr *)&addr, sizeof(addr))) { if (errno == EADDRNOTAVAIL) { @@ -218,7 +221,6 @@ udp_send(struct tport *tp, const u_char { struct udp_port *p = (struct udp_port *)tp; struct cmsghdr *cmsg; - struct in_addr *src_addr; struct msghdr msg; char cbuf[CMSG_SPACE(sizeof(struct in_addr))]; struct iovec iov; @@ -231,15 +233,20 @@ udp_send(struct tport *tp, const u_char msg.msg_iovlen = 1; msg.msg_name = __DECONST(void *, addr); msg.msg_namelen = addrlen; - msg.msg_control = cbuf; - msg.msg_controllen = sizeof(cbuf); - cmsg = CMSG_FIRSTHDR(&msg); - cmsg->cmsg_level = IPPROTO_IP; - cmsg->cmsg_type = IP_SENDSRCADDR; - cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); - src_addr = (struct in_addr *)(void*)CMSG_DATA(cmsg); - memcpy(src_addr, &p->recv_addr, sizeof(struct in_addr)); + if (p->recvdstaddr) { + msg.msg_control = cbuf; + msg.msg_controllen = sizeof(cbuf); + + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = IPPROTO_IP; + cmsg->cmsg_type = IP_SENDSRCADDR; + cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); + memcpy(CMSG_DATA(cmsg), &p->dstaddr, sizeof(struct in_addr)); + } else { + msg.msg_control = NULL; + msg.msg_controllen = 0; + } return (sendmsg(p->input.fd, &msg, 0)); } @@ -260,11 +267,12 @@ check_priv_dgram(struct port_input *pi, * Each receive should return one datagram. */ static ssize_t -recv_dgram(struct port_input *pi, struct in_addr *laddr) +udp_recv(struct tport *tp, struct port_input *pi) { u_char embuf[1000]; char cbuf[CMSG_SPACE(SOCKCREDSIZE(CMGROUP_MAX)) + CMSG_SPACE(sizeof(struct in_addr))]; + struct udp_port *p = (struct udp_port *)tp; struct msghdr msg; struct iovec iov[1]; ssize_t len; @@ -316,7 +324,8 @@ recv_dgram(struct port_input *pi, struct cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_RECVDSTADDR) - memcpy(laddr, CMSG_DATA(cmsg), sizeof(struct in_addr)); + memcpy(&p->dstaddr, CMSG_DATA(cmsg), + sizeof(struct in_addr)); if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS) cred = (struct sockcred *)CMSG_DATA(cmsg); @@ -329,42 +338,6 @@ recv_dgram(struct port_input *pi, struct } /* - * Receive something - */ -static ssize_t -udp_recv(struct tport *tp, struct port_input *pi) -{ - struct udp_port *p = (struct udp_port *)tp; - struct cmsghdr *cmsgp; - struct in_addr *laddr; - struct msghdr msg; - char cbuf[CMSG_SPACE(sizeof(struct in_addr))]; - ssize_t ret; - - memset(cbuf, 0, sizeof(cbuf)); - - msg.msg_control = cbuf; - msg.msg_controllen = sizeof(cbuf); - - cmsgp = CMSG_FIRSTHDR(&msg); - cmsgp->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); - cmsgp->cmsg_level = IPPROTO_IP; - cmsgp->cmsg_type = IP_SENDSRCADDR; - laddr = (struct in_addr *)CMSG_DATA(cmsgp); - - ret = recv_dgram(pi, laddr); - - memcpy(&p->recv_addr, laddr, sizeof(struct in_addr)); - - if (laddr->s_addr == INADDR_ANY) { - msg.msg_control = NULL; - msg.msg_controllen = 0; - } - - return (ret); -} - -/* * Port table */ int Modified: head/contrib/bsnmp/snmpd/trans_udp.h ============================================================================== --- head/contrib/bsnmp/snmpd/trans_udp.h Tue Jan 17 03:44:45 2017 (r312330) +++ head/contrib/bsnmp/snmpd/trans_udp.h Tue Jan 17 03:52:57 2017 (r312331) @@ -39,7 +39,9 @@ struct udp_port { struct port_input input; /* common input stuff */ struct sockaddr_in ret; /* the return address */ - struct in_addr recv_addr; /* the address the request was sent to */ + + bool recvdstaddr; /* IP_RECVDSTADDR is on */ + struct in_addr dstaddr; /* address the request was sent to */ }; /* argument for open call */
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