The old code only worked if "struct openvpn*pktinfo" happened to use
the same structure packing as the CMSG_SPACE() / CMSG_LEN() macros
(which are part of the official API, see RFC 2292).
Get rid of "struct openvpn_*_pktinfo" definitions, replace them by
an opaque buffer sized large enough to fit IPv4 and IPv6 packet info
messages, as defined by CMSG_SPACE(sizeof(struct ...)).
On 32 bit platforms, the net result is the same. On 64 bit platforms,
the new buffer is bigger than openvpn_pktinfo was, fixing an overflow
with ipi6_ifindex corruption on reception, and EINVAL on sendmsg().
The IPv4 related changes are only side effects of using the new buffer.
Fixes: FreeBSD 10.3/amd64, FreeBSD 9.3/sparc64, OpenBSD 6.0/amd64,
NetBSD 7.0.1/i386.
Note: --multihome for IPv4 on NetBSD is still broken and non-fixable(!)
as NetBSD lacks the necessary kernel code for the sendmsg() side.
Verified that "--multihome works as well as before" on FreeBSD 7.4/amd64,
NetBSD 5.1/amd64, OpenBSD 4.9/i386, Linux/x86_64, Linux/i386,
OpenSolaris 10 (--multihome needs -D_XPG4_2, see trac #750)
See also: ip(4), ip6(4), recv(2)
Trac #634, #327, #28
Signed-off-by: Gert Doering <g...@greenie.muc.de>
---
src/openvpn/socket.c | 57 +++++++++++++++++++++++-----------------------------
1 file changed, 25 insertions(+), 32 deletions(-)
diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index e096132..184c7ad 100644
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -2863,27 +2863,16 @@ link_socket_read_tcp (struct link_socket *sock,
#if ENABLE_IP_PKTINFO
-#pragma pack(1) /* needed to keep structure size consistent for 32 vs. 64-bit
architectures */
-struct openvpn_in4_pktinfo
-{
- struct cmsghdr cmsghdr;
+/* make the buffer large enough to handle ancilliary socket data for
+ * both IPv4 and IPv6 destination addresses, plus padding (see RFC 2292)
+ */
#if defined(HAVE_IN_PKTINFO) && defined(HAVE_IPI_SPEC_DST)
- struct in_pktinfo pi4;
-#elif defined(IP_RECVDSTADDR)
- struct in_addr pi4;
+#define PKTINFO_BUF_SIZE max_int( CMSG_SPACE(sizeof (struct in6_pktinfo)), \
+ CMSG_SPACE(sizeof (struct in_pktinfo)) )
+#else
+#define PKTINFO_BUF_SIZE max_int( CMSG_SPACE(sizeof (struct in6_pktinfo)), \
+ CMSG_SPACE(sizeof (struct in_addr)) )
#endif
-};
-struct openvpn_in6_pktinfo
-{
- struct cmsghdr cmsghdr;
- struct in6_pktinfo pi6;
-};
-
-union openvpn_pktinfo {
- struct openvpn_in4_pktinfo msgpi4;
- struct openvpn_in6_pktinfo msgpi6;
-};
-#pragma pack()
static socklen_t
link_socket_read_udp_posix_recvmsg (struct link_socket *sock,
@@ -2891,7 +2880,7 @@ link_socket_read_udp_posix_recvmsg (struct link_socket
*sock,
struct link_socket_actual *from)
{
struct iovec iov;
- union openvpn_pktinfo opi;
+ uint8_t pktinfo_buf[PKTINFO_BUF_SIZE];
struct msghdr mesg;
socklen_t fromlen = sizeof (from->dest.addr);
@@ -2901,8 +2890,8 @@ link_socket_read_udp_posix_recvmsg (struct link_socket
*sock,
mesg.msg_iovlen = 1;
mesg.msg_name = &from->dest.addr;
mesg.msg_namelen = fromlen;
- mesg.msg_control = &opi;
- mesg.msg_controllen = sizeof opi;
+ mesg.msg_control = pktinfo_buf;
+ mesg.msg_controllen = sizeof pktinfo_buf;
buf->len = recvmsg (sock->sd, &mesg, 0);
if (buf->len >= 0)
{
@@ -2914,13 +2903,14 @@ link_socket_read_udp_posix_recvmsg (struct link_socket
*sock,
#if defined(HAVE_IN_PKTINFO) && defined(HAVE_IPI_SPEC_DST)
&& cmsg->cmsg_level == SOL_IP
&& cmsg->cmsg_type == IP_PKTINFO
+ && cmsg->cmsg_len >= CMSG_LEN(sizeof(struct in_pktinfo)) )
#elif defined(IP_RECVDSTADDR)
&& cmsg->cmsg_level == IPPROTO_IP
&& cmsg->cmsg_type == IP_RECVDSTADDR
+ && cmsg->cmsg_len >= CMSG_LEN(sizeof(struct in_addr)) )
#else
#error ENABLE_IP_PKTINFO is set without IP_PKTINFO xor IP_RECVDSTADDR (fix
syshead.h)
#endif
- && cmsg->cmsg_len >= sizeof (struct openvpn_in4_pktinfo))
{
#if defined(HAVE_IN_PKTINFO) && defined(HAVE_IPI_SPEC_DST)
struct in_pktinfo *pkti = (struct in_pktinfo *) CMSG_DATA (cmsg);
@@ -2936,7 +2926,7 @@ link_socket_read_udp_posix_recvmsg (struct link_socket
*sock,
&& CMSG_NXTHDR (&mesg, cmsg) == NULL
&& cmsg->cmsg_level == IPPROTO_IPV6
&& cmsg->cmsg_type == IPV6_PKTINFO
- && cmsg->cmsg_len >= sizeof (struct openvpn_in6_pktinfo))
+ && cmsg->cmsg_len >= CMSG_LEN(sizeof(struct in6_pktinfo)) )
{
struct in6_pktinfo *pkti6 = (struct in6_pktinfo *) CMSG_DATA (cmsg);
from->pi.in6.ipi6_ifindex = pkti6->ipi6_ifindex;
@@ -3007,7 +2997,7 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
struct iovec iov;
struct msghdr mesg;
struct cmsghdr *cmsg;
- union openvpn_pktinfo opi;
+ uint8_t pktinfo_buf[PKTINFO_BUF_SIZE];
iov.iov_base = BPTR (buf);
iov.iov_len = BLEN (buf);
@@ -3019,12 +3009,12 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
{
mesg.msg_name = &to->dest.addr.sa;
mesg.msg_namelen = sizeof (struct sockaddr_in);
- mesg.msg_control = &opi;
+ mesg.msg_control = pktinfo_buf;
mesg.msg_flags = 0;
#if defined(HAVE_IN_PKTINFO) && defined(HAVE_IPI_SPEC_DST)
- mesg.msg_controllen = sizeof (struct openvpn_in4_pktinfo);
+ mesg.msg_controllen = CMSG_SPACE(sizeof (struct in_pktinfo));
cmsg = CMSG_FIRSTHDR (&mesg);
- cmsg->cmsg_len = sizeof (struct openvpn_in4_pktinfo);
+ cmsg->cmsg_len = CMSG_LEN(sizeof (struct in_pktinfo));
cmsg->cmsg_level = SOL_IP;
cmsg->cmsg_type = IP_PKTINFO;
{
@@ -3035,7 +3025,7 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
pkti->ipi_addr.s_addr = 0;
}
#elif defined(IP_RECVDSTADDR)
- ASSERT( CMSG_SPACE(sizeof (struct in_addr)) <= sizeof(opi) );
+ ASSERT( CMSG_SPACE(sizeof (struct in_addr)) <= sizeof(pktinfo_buf) );
mesg.msg_controllen = CMSG_SPACE(sizeof (struct in_addr));
cmsg = CMSG_FIRSTHDR (&mesg);
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
@@ -3052,13 +3042,16 @@ link_socket_write_udp_posix_sendmsg (struct link_socket
*sock,
struct in6_pktinfo *pkti6;
mesg.msg_name = &to->dest.addr.sa;
mesg.msg_namelen = sizeof (struct sockaddr_in6);
- mesg.msg_control = &opi;
- mesg.msg_controllen = sizeof (struct openvpn_in6_pktinfo);
+
+ ASSERT( CMSG_SPACE(sizeof (struct in6_pktinfo)) <= sizeof(pktinfo_buf)
);
+ mesg.msg_control = pktinfo_buf;
+ mesg.msg_controllen = CMSG_SPACE(sizeof (struct in6_pktinfo));
mesg.msg_flags = 0;
cmsg = CMSG_FIRSTHDR (&mesg);
- cmsg->cmsg_len = sizeof (struct openvpn_in6_pktinfo);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
+
pkti6 = (struct in6_pktinfo *) CMSG_DATA (cmsg);
pkti6->ipi6_ifindex = to->pi.in6.ipi6_ifindex;
pkti6->ipi6_addr = to->pi.in6.ipi6_addr;
--
2.9.0
------------------------------------------------------------------------------
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