From a258f4915a2674d77e656755e5a4fa23059f778a Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 24 Apr 2020 23:36:03 +0200 Subject: [PATCH 1/3] tree-wide: use CMSG_SPACE() (and not CMSG_LEN()) to allocate control buffers We need to use the CMSG_SPACE() macro to size the control buffers, not CMSG_LEN(). The former is rounded up to next alignment boundary, the latter is not. The former should be used for allocations, the latter for encoding how much of it is actually initialized. See cmsg(3) man page for details about this. Given how confusing this is, I guess we don't have to be too ashamed here, in most cases we actually did get this right. --- src/libsystemd-network/sd-dhcp-client.c | 2 +- src/libsystemd-network/sd-dhcp-server.c | 4 ++-- src/libsystemd/sd-bus/bus-socket.c | 6 ++++-- src/resolve/resolved-manager.c | 8 ++++---- 4 files changed, 11 insertions(+), 9 deletions(-) diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 0cff6c4f33d..47f60d4a2a3 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -1899,7 +1899,7 @@ static int client_receive_message_raw( sd_dhcp_client *client = userdata; _cleanup_free_ DHCPPacket *packet = NULL; - uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))]; + uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct tpacket_auxdata))]; struct iovec iov = {}; struct msghdr msg = { .msg_iov = &iov, diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c index 7fa0dc2812a..59792af6863 100644 --- a/src/libsystemd-network/sd-dhcp-server.c +++ b/src/libsystemd-network/sd-dhcp-server.c @@ -267,7 +267,7 @@ static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, .iov_base = message, .iov_len = len, }; - uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))] = {}; + uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct in_pktinfo))] = {}; struct msghdr msg = { .msg_name = &dest, .msg_namelen = sizeof(dest.in), @@ -970,7 +970,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, static int server_receive_message(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_free_ DHCPMessage *message = NULL; - uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))]; + uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct in_pktinfo))]; sd_dhcp_server *server = userdata; struct iovec iov = {}; struct msghdr msg = { diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c index b2b6732c317..e336dbb62ed 100644 --- a/src/libsystemd/sd-bus/bus-socket.c +++ b/src/libsystemd/sd-bus/bus-socket.c @@ -1037,8 +1037,10 @@ int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) { if (m->n_fds > 0 && *idx == 0) { struct cmsghdr *control; - mh.msg_control = control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds)); - mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds); + mh.msg_controllen = CMSG_SPACE(sizeof(int) * m->n_fds); + mh.msg_control = alloca0(mh.msg_controllen); + control = CMSG_FIRSTHDR(&mh); + control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds); control->cmsg_level = SOL_SOCKET; control->cmsg_type = SCM_RIGHTS; memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds); diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 1849fc1b1d9..69630cf49d3 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -962,10 +962,10 @@ static int manager_ipv4_send( struct in_pktinfo *pi; mh.msg_control = &control; - mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); + mh.msg_controllen = sizeof(control); cmsg = CMSG_FIRSTHDR(&mh); - cmsg->cmsg_len = mh.msg_controllen; + cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); cmsg->cmsg_level = IPPROTO_IP; cmsg->cmsg_type = IP_PKTINFO; @@ -1021,10 +1021,10 @@ static int manager_ipv6_send( struct in6_pktinfo *pi; mh.msg_control = &control; - mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); + mh.msg_controllen = sizeof(control); cmsg = CMSG_FIRSTHDR(&mh); - cmsg->cmsg_len = mh.msg_controllen; + cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; From 0d9d333672167f7c4586c1708eee53066ce8f55d Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 24 Apr 2020 23:38:47 +0200 Subject: [PATCH 2/3] tree-wide: remove redundant assignments We already initialize the fields a few lines up to the very same values, hence remove this. --- src/basic/socket-util.c | 2 -- src/portable/portable.c | 1 - 2 files changed, 3 deletions(-) diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c index b502a62a248..a23dd6cbed5 100644 --- a/src/basic/socket-util.c +++ b/src/basic/socket-util.c @@ -850,8 +850,6 @@ ssize_t send_one_fd_iov_sa( cmsg->cmsg_type = SCM_RIGHTS; cmsg->cmsg_len = CMSG_LEN(sizeof(int)); memcpy(CMSG_DATA(cmsg), &fd, sizeof(int)); - - mh.msg_controllen = CMSG_SPACE(sizeof(int)); } k = sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags); if (k < 0) diff --git a/src/portable/portable.c b/src/portable/portable.c index 49087179c87..4a881460dbb 100644 --- a/src/portable/portable.c +++ b/src/portable/portable.c @@ -155,7 +155,6 @@ static int send_item( cmsg->cmsg_len = CMSG_LEN(sizeof(int)); memcpy(CMSG_DATA(cmsg), &data_fd, sizeof(int)); - mh.msg_controllen = CMSG_SPACE(sizeof(int)); iovec = IOVEC_MAKE_STRING(name); if (sendmsg(socket_fd, &mh, MSG_NOSIGNAL) < 0) From fb29cdbef21f1d66e2ebe600601897b6578d3959 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 24 Apr 2020 23:54:25 +0200 Subject: [PATCH 3/3] tree-wide: make sure our control buffers are properly aligned We always need to make them unions with a "struct cmsghdr" in them, so that things properly aligned. Otherwise we might end up at an unaligned address and the counting goes all wrong, possibly making the kernel refuse our buffers. Also, let's make sure we initialize the control buffers to zero when sending, but leave them uninitialized when reading. Both the alignment and the initialization thing is mentioned in the cmsg(3) man page. --- src/basic/socket-util.c | 10 ++-------- src/basic/socket-util.h | 11 +++++++++++ src/core/manager.c | 7 ++----- src/coredump/coredump.c | 5 +---- src/home/homed-manager.c | 5 +---- src/import/importd.c | 7 ++----- src/journal/journald-server.c | 23 ++++++++--------------- src/journal/journald-stream.c | 6 +++--- src/journal/journald-syslog.c | 5 +---- src/libsystemd-network/icmp6-util.c | 8 +++----- src/libsystemd-network/sd-dhcp-client.c | 6 +++--- src/libsystemd-network/sd-dhcp-server.c | 12 ++++++------ src/libsystemd/sd-bus/bus-socket.c | 10 ++-------- src/libsystemd/sd-device/device-monitor.c | 6 +++--- src/nspawn/nspawn.c | 7 ++----- src/portable/portable.c | 10 ++-------- src/resolve/resolved-dns-stream.c | 7 ++----- src/resolve/resolved-manager.c | 20 ++++++-------------- src/shared/ask-password-api.c | 6 +----- src/timesync/timesyncd-manager.c | 5 +---- src/udev/udev-ctrl.c | 6 +++--- src/udev/udevd.c | 5 +---- 22 files changed, 66 insertions(+), 121 deletions(-) diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c index a23dd6cbed5..0be098df2ea 100644 --- a/src/basic/socket-util.c +++ b/src/basic/socket-util.c @@ -818,10 +818,7 @@ ssize_t send_one_fd_iov_sa( const struct sockaddr *sa, socklen_t len, int flags) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control = {}; struct msghdr mh = { .msg_name = (struct sockaddr*) sa, .msg_namelen = len, @@ -875,10 +872,7 @@ ssize_t receive_one_fd_iov( int flags, int *ret_fd) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; struct msghdr mh = { .msg_control = &control, .msg_controllen = sizeof(control), diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h index fba4efef814..6f366c04299 100644 --- a/src/basic/socket-util.h +++ b/src/basic/socket-util.h @@ -166,6 +166,17 @@ struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t leng (ctype*) (_found ? CMSG_DATA(_found) : NULL); \ }) +/* Resolves to a type that can carry cmsghdr structures. Make sure things are properly aligned, i.e. the type + * itself is placed properly in memory and the size is also aligned to what's appropriate for "cmsghdr" + * structures. */ +#define CMSG_BUFFER_TYPE(size) \ + union { \ + struct cmsghdr cmsghdr; \ + uint8_t buf[size]; \ + uint8_t align_check[(size) >= CMSG_SPACE(0) && \ + (size) == CMSG_ALIGN(size) ? 1 : -1]; \ + } + /* * Certain hardware address types (e.g Infiniband) do not fit into sll_addr * (8 bytes) and run over the structure. This macro returns the correct size that diff --git a/src/core/manager.c b/src/core/manager.c index 7c207bed6e7..09dc92d599a 100644 --- a/src/core/manager.c +++ b/src/core/manager.c @@ -2349,11 +2349,8 @@ static int manager_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t .iov_base = buf, .iov_len = sizeof(buf)-1, }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) + - CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)) control; struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1, diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c index ff4238c91d7..42231dbd6b6 100644 --- a/src/coredump/coredump.c +++ b/src/coredump/coredump.c @@ -884,10 +884,7 @@ static int process_socket(int fd) { log_debug("Processing coredump received on stdin..."); for (;;) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; struct msghdr mh = { .msg_control = &control, .msg_controllen = sizeof(control), diff --git a/src/home/homed-manager.c b/src/home/homed-manager.c index 8ea93120d07..70673fc84d6 100644 --- a/src/home/homed-manager.c +++ b/src/home/homed-manager.c @@ -946,10 +946,7 @@ static ssize_t read_datagram(int fd, struct ucred *ret_sender, void **ret) { return -ENOMEM; if (ret_sender) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; bool found_ucred = false; struct cmsghdr *cmsg; struct msghdr mh; diff --git a/src/import/importd.c b/src/import/importd.c index 9408edece10..d799a10f94b 100644 --- a/src/import/importd.c +++ b/src/import/importd.c @@ -550,11 +550,8 @@ static int manager_on_notify(sd_event_source *s, int fd, uint32_t revents, void .iov_base = buf, .iov_len = sizeof(buf)-1, }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) + - CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)) control; struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1, diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c index 981a569453a..9efa65a2942 100644 --- a/src/journal/journald-server.c +++ b/src/journal/journald-server.c @@ -1268,21 +1268,14 @@ int server_process_datagram( int *fds = NULL, v = 0; size_t n_fds = 0; - union { - struct cmsghdr cmsghdr; - - /* We use NAME_MAX space for the SELinux label - * here. The kernel currently enforces no - * limit, but according to suggestions from - * the SELinux people this will change and it - * will probably be identical to NAME_MAX. For - * now we use that, but this should be updated - * one day when the final limit is known. */ - uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) + - CMSG_SPACE(sizeof(struct timeval)) + - CMSG_SPACE(sizeof(int)) + /* fd */ - CMSG_SPACE(NAME_MAX)]; /* selinux label */ - } control = {}; + /* We use NAME_MAX space for the SELinux label here. The kernel currently enforces no limit, but + * according to suggestions from the SELinux people this will change and it will probably be + * identical to NAME_MAX. For now we use that, but this should be updated one day when the final + * limit is known. */ + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(struct timeval)) + + CMSG_SPACE(sizeof(int)) + /* fd */ + CMSG_SPACE(NAME_MAX) /* selinux label */) control; union sockaddr_union sa = {}; diff --git a/src/journal/journald-stream.c b/src/journal/journald-stream.c index 202ac3cda28..4dadbd62bec 100644 --- a/src/journal/journald-stream.c +++ b/src/journal/journald-stream.c @@ -489,7 +489,7 @@ static int stdout_stream_scan(StdoutStream *s, bool force_flush) { } static int stdout_stream_process(sd_event_source *es, int fd, uint32_t revents, void *userdata) { - uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; StdoutStream *s = userdata; struct ucred *ucred; struct iovec iovec; @@ -500,8 +500,8 @@ static int stdout_stream_process(sd_event_source *es, int fd, uint32_t revents, struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1, - .msg_control = buf, - .msg_controllen = sizeof(buf), + .msg_control = &control, + .msg_controllen = sizeof(control), }; assert(s); diff --git a/src/journal/journald-syslog.c b/src/journal/journald-syslog.c index 1325b563854..46013c38784 100644 --- a/src/journal/journald-syslog.c +++ b/src/journal/journald-syslog.c @@ -39,10 +39,7 @@ static void forward_syslog_iovec( .msg_iovlen = n_iovec, }; struct cmsghdr *cmsg; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; const char *j; int r; diff --git a/src/libsystemd-network/icmp6-util.c b/src/libsystemd-network/icmp6-util.c index 1a51c22a8d0..bdd94867ac3 100644 --- a/src/libsystemd-network/icmp6-util.c +++ b/src/libsystemd-network/icmp6-util.c @@ -147,11 +147,9 @@ int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) { int icmp6_receive(int fd, void *buffer, size_t size, struct in6_addr *dst, triple_timestamp *timestamp) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int)) + /* ttl */ - CMSG_SPACE(sizeof(struct timeval))]; - } control = {}; + + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int)) + /* ttl */ + CMSG_SPACE(sizeof(struct timeval))) control; struct iovec iov = {}; union sockaddr_union sa = {}; struct msghdr msg = { diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c index 47f60d4a2a3..ee0e63e113c 100644 --- a/src/libsystemd-network/sd-dhcp-client.c +++ b/src/libsystemd-network/sd-dhcp-client.c @@ -1899,13 +1899,13 @@ static int client_receive_message_raw( sd_dhcp_client *client = userdata; _cleanup_free_ DHCPPacket *packet = NULL; - uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct tpacket_auxdata))]; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct tpacket_auxdata))) control; struct iovec iov = {}; struct msghdr msg = { .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = cmsgbuf, - .msg_controllen = sizeof(cmsgbuf), + .msg_control = &control, + .msg_controllen = sizeof(control), }; struct cmsghdr *cmsg; bool checksum = true; diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c index 59792af6863..14f2bcb4fb8 100644 --- a/src/libsystemd-network/sd-dhcp-server.c +++ b/src/libsystemd-network/sd-dhcp-server.c @@ -267,14 +267,14 @@ static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, .iov_base = message, .iov_len = len, }; - uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct in_pktinfo))] = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {}; struct msghdr msg = { .msg_name = &dest, .msg_namelen = sizeof(dest.in), .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = cmsgbuf, - .msg_controllen = sizeof(cmsgbuf), + .msg_control = &control, + .msg_controllen = sizeof(control), }; struct cmsghdr *cmsg; struct in_pktinfo *pktinfo; @@ -970,14 +970,14 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, static int server_receive_message(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_free_ DHCPMessage *message = NULL; - uint8_t cmsgbuf[CMSG_SPACE(sizeof(struct in_pktinfo))]; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control; sd_dhcp_server *server = userdata; struct iovec iov = {}; struct msghdr msg = { .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = cmsgbuf, - .msg_controllen = sizeof(cmsgbuf), + .msg_control = &control, + .msg_controllen = sizeof(control), }; struct cmsghdr *cmsg; ssize_t buflen, len; diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c index e336dbb62ed..acc313d164b 100644 --- a/src/libsystemd/sd-bus/bus-socket.c +++ b/src/libsystemd/sd-bus/bus-socket.c @@ -518,10 +518,7 @@ static int bus_socket_read_auth(sd_bus *b) { ssize_t k; int r; void *p; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control; bool handle_cmsg = false; assert(b); @@ -1169,10 +1166,7 @@ int bus_socket_read_message(sd_bus *bus) { size_t need; int r; void *b; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control; bool handle_cmsg = false; assert(bus); diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c index 42753abe083..20a422c77cf 100644 --- a/src/libsystemd/sd-device/device-monitor.c +++ b/src/libsystemd/sd-device/device-monitor.c @@ -361,13 +361,13 @@ int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) { .iov_base = &buf, .iov_len = sizeof(buf) }; - char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; union sockaddr_union snl; struct msghdr smsg = { .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = cred_msg, - .msg_controllen = sizeof(cred_msg), + .msg_control = &control, + .msg_controllen = sizeof(control), .msg_name = &snl, .msg_namelen = sizeof(snl), }; diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 43c6b6845ed..8e8881749aa 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -3687,11 +3687,8 @@ static int nspawn_dispatch_notify_fd(sd_event_source *source, int fd, uint32_t r .iov_base = buf, .iov_len = sizeof(buf)-1, }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) + - CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred)) + + CMSG_SPACE(sizeof(int) * NOTIFY_FD_MAX)) control; struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1, diff --git a/src/portable/portable.c b/src/portable/portable.c index 4a881460dbb..f47a3329fb9 100644 --- a/src/portable/portable.c +++ b/src/portable/portable.c @@ -127,10 +127,7 @@ static int send_item( const char *name, int fd) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control = {}; struct iovec iovec; struct msghdr mh = { .msg_control = &control, @@ -168,10 +165,7 @@ static int recv_item( char **ret_name, int *ret_fd) { - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(int))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int))) control; char buffer[PATH_MAX+2]; struct iovec iov = IOVEC_INIT(buffer, sizeof(buffer)-1); struct msghdr mh = { diff --git a/src/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c index 9c47cd60e42..bbaffc165ac 100644 --- a/src/resolve/resolved-dns-stream.c +++ b/src/resolve/resolved-dns-stream.c @@ -87,11 +87,8 @@ static int dns_stream_complete(DnsStream *s, int error) { } static int dns_stream_identify(DnsStream *s) { - union { - struct cmsghdr header; /* For alignment */ - uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) - + EXTRA_CMSG_SPACE /* kernel appears to require extra space */]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + + EXTRA_CMSG_SPACE /* kernel appears to require extra space */) control; struct msghdr mh = {}; struct cmsghdr *cmsg; socklen_t sl; diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index 69630cf49d3..1da590b68ac 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -741,12 +741,9 @@ Manager *manager_free(Manager *m) { int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - union { - struct cmsghdr header; /* For alignment */ - uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) - + CMSG_SPACE(int) /* ttl/hoplimit */ - + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + + CMSG_SPACE(int) /* ttl/hoplimit */ + + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control; union sockaddr_union sa; struct iovec iov; struct msghdr mh = { @@ -930,10 +927,8 @@ static int manager_ipv4_send( uint16_t port, const struct in_addr *source, DnsPacket *p) { - union { - struct cmsghdr header; /* For alignment */ - uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))]; - } control = {}; + + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {}; union sockaddr_union sa; struct iovec iov; struct msghdr mh = { @@ -988,10 +983,7 @@ static int manager_ipv6_send( const struct in6_addr *source, DnsPacket *p) { - union { - struct cmsghdr header; /* For alignment */ - uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {}; union sockaddr_union sa; struct iovec iov; struct msghdr mh = { diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c index e690b0fa6ea..4c5781a11ad 100644 --- a/src/shared/ask-password-api.c +++ b/src/shared/ask-password-api.c @@ -859,13 +859,10 @@ int ask_password_agent( pollfd[FD_INOTIFY].events = POLLIN; for (;;) { + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; char passphrase[LINE_MAX+1]; struct iovec iovec; struct ucred *ucred; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; - } control; ssize_t n; int k; usec_t t; @@ -917,7 +914,6 @@ int ask_password_agent( iovec = IOVEC_MAKE(passphrase, sizeof(passphrase)); - zero(control); struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1, diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c index 2980f79b16f..dadf213a809 100644 --- a/src/timesync/timesyncd-manager.c +++ b/src/timesync/timesyncd-manager.c @@ -407,10 +407,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re .iov_base = &ntpmsg, .iov_len = sizeof(ntpmsg), }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct timeval))]; - } control; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct timeval))) control; union sockaddr_union server_addr; struct msghdr msghdr = { .msg_iov = &iov, diff --git a/src/udev/udev-ctrl.c b/src/udev/udev-ctrl.c index d067279f3e1..1e51f22e260 100644 --- a/src/udev/udev-ctrl.c +++ b/src/udev/udev-ctrl.c @@ -189,12 +189,12 @@ static int udev_ctrl_connection_event_handler(sd_event_source *s, int fd, uint32 _cleanup_(udev_ctrl_disconnect_and_listen_againp) struct udev_ctrl *uctrl = NULL; struct udev_ctrl_msg_wire msg_wire; struct iovec iov = IOVEC_MAKE(&msg_wire, sizeof(struct udev_ctrl_msg_wire)); - char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; struct msghdr smsg = { .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = cred_msg, - .msg_controllen = sizeof(cred_msg), + .msg_control = &control, + .msg_controllen = sizeof(control), }; struct cmsghdr *cmsg; struct ucred *cred; diff --git a/src/udev/udevd.c b/src/udev/udevd.c index cfda47f849b..d3f9d532e18 100644 --- a/src/udev/udevd.c +++ b/src/udev/udevd.c @@ -906,10 +906,7 @@ static int on_worker(sd_event_source *s, int fd, uint32_t revents, void *userdat .iov_base = &msg, .iov_len = sizeof(msg), }; - union { - struct cmsghdr cmsghdr; - uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; - } control = {}; + CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control; struct msghdr msghdr = { .msg_iov = &iovec, .msg_iovlen = 1,