From 5a282fc000a52fe98a31ac69832678b1d1d5778d Mon Sep 17 00:00:00 2001 From: Maciej Wereski Date: Tue, 8 Sep 2015 15:36:30 +0200 Subject: [PATCH] sd_pid_notify_with_fds: fix computing msg_controllen CMSG_SPACE(0) may return value other than 0. This caused sendmsg to fail with EINVAL, when have_pid or n_fds was 0. Cherry-picked from: a5bd3c32abb00ad945282568fd1a97c180b68047 Resolves: #1381743 --- src/libsystemd/sd-daemon/sd-daemon.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/libsystemd/sd-daemon/sd-daemon.c b/src/libsystemd/sd-daemon/sd-daemon.c index 1474321c9..2c4dd9d22 100644 --- a/src/libsystemd/sd-daemon/sd-daemon.c +++ b/src/libsystemd/sd-daemon/sd-daemon.c @@ -397,8 +397,9 @@ _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char have_pid = pid != 0 && pid != getpid(); if (n_fds > 0 || have_pid) { - msghdr.msg_controllen = CMSG_SPACE(sizeof(int) * n_fds) + - CMSG_SPACE(sizeof(struct ucred) * have_pid); + /* CMSG_SPACE(0) may return value different then zero, which results in miscalculated controllen. */ + msghdr.msg_controllen = (n_fds ? CMSG_SPACE(sizeof(int) * n_fds) : 0) + + CMSG_SPACE(sizeof(struct ucred)) * have_pid; msghdr.msg_control = alloca(msghdr.msg_controllen); cmsg = CMSG_FIRSTHDR(&msghdr);