From b2eac2dedd62224df07148a9e42eae0197902c00 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Sun, 23 Apr 2017 00:00:10 +0000 Subject: Align ancillary buffers on struct cmsghdr and int boundaries --- src/libunixonacid/unixmessage_sender_flush.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'src/libunixonacid/unixmessage_sender_flush.c') diff --git a/src/libunixonacid/unixmessage_sender_flush.c b/src/libunixonacid/unixmessage_sender_flush.c index e7d4299..eb2645c 100644 --- a/src/libunixonacid/unixmessage_sender_flush.c +++ b/src/libunixonacid/unixmessage_sender_flush.c @@ -21,6 +21,13 @@ #define MSG_NOSIGNAL 0 #endif +union aligner_u +{ + struct cmsghdr cmsghdr ; + int i ; +} ; + + /* XXX: sendmsg/recvmsg is badly, badly specified. XXX: We assume ancillary data is attached to the first byte. @@ -68,7 +75,7 @@ int unixmessage_sender_flush (unixmessage_sender_t *b) { .iov_base = pack, .iov_len = 6 }, { .iov_base = b->data.s + offsets[b->head].left, .iov_len = len } } ; - char ancilbuf[CMSG_SPACE(nfds * sizeof(int))] ; + union aligner_u ancilbuf[1 + CMSG_SPACE(nfds * sizeof(int)) / sizeof(union aligner_u)] ; struct msghdr hdr = { .msg_name = 0, @@ -76,7 +83,7 @@ int unixmessage_sender_flush (unixmessage_sender_t *b) .msg_iov = v, .msg_iovlen = 2, .msg_control = nfds ? ancilbuf : 0, - .msg_controllen = nfds ? sizeof(ancilbuf) : 0 + .msg_controllen = nfds ? CMSG_SPACE(nfds * sizeof(int)) : 0 } ; uint32_pack_big(pack, (uint32_t)len) ; uint16_pack_big(pack + 4, (uint16_t)nfds) ; @@ -84,7 +91,7 @@ int unixmessage_sender_flush (unixmessage_sender_t *b) { struct cmsghdr *cp = CMSG_FIRSTHDR(&hdr) ; size_t i = 0 ; - memset(ancilbuf, 0, sizeof(ancilbuf)) ; + memset(hdr.msg_control, 0, hdr.msg_controllen) ; cp->cmsg_level = SOL_SOCKET ; cp->cmsg_type = SCM_RIGHTS ; cp->cmsg_len = CMSG_LEN(nfds * sizeof(int)) ; -- cgit v1.2.3