From 2ef339009976dda85ff702b92de1f98625602b0a Mon Sep 17 00:00:00 2001 From: PHO Date: Tue, 3 Dec 2013 12:43:04 +0900 Subject: [PATCH] Test the value of msg_controllen for platforms whose CMSG_FIRSTHDR() does not test it for us. As RFC 2292 points out, some platforms (e.g. Darwin 9.8.0) provide CMSG_FIRSTHDR(msg) which just returns msg.msg_control without first checking if msg.msg_controllen is non-zero. We need a workaround for such platforms not to let _xcb_in_read() segfault. --- src/xcb_in.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/src/xcb_in.c b/src/xcb_in.c index fd6c2ef..95087be 100644 --- a/src/xcb_in.c +++ b/src/xcb_in.c @@ -918,11 +918,13 @@ int _xcb_in_read(xcb_connection_t *c) #if HAVE_SENDMSG struct cmsghdr *hdr; - for (hdr = CMSG_FIRSTHDR(&msg); hdr; hdr = CMSG_NXTHDR(&msg, hdr)) { - if (hdr->cmsg_level == SOL_SOCKET && hdr->cmsg_type == SCM_RIGHTS) { - int nfd = (hdr->cmsg_len - CMSG_LEN(0)) / sizeof (int); - memcpy(&c->in.in_fd.fd[c->in.in_fd.nfd], CMSG_DATA(hdr), nfd * sizeof (int)); - c->in.in_fd.nfd += nfd; + if (msg.msg_controllen >= sizeof (struct cmsghdr)) { + for (hdr = CMSG_FIRSTHDR(&msg); hdr; hdr = CMSG_NXTHDR(&msg, hdr)) { + if (hdr->cmsg_level == SOL_SOCKET && hdr->cmsg_type == SCM_RIGHTS) { + int nfd = (hdr->cmsg_len - CMSG_LEN(0)) / sizeof (int); + memcpy(&c->in.in_fd.fd[c->in.in_fd.nfd], CMSG_DATA(hdr), nfd * sizeof (int)); + c->in.in_fd.nfd += nfd; + } } } #endif -- 1.8.4.3