[libvirt] [PATCH] systemd: fix ready notification on abstract socket
At least with systemd v210, NOTIFY_SOCKET is abstact, e.g. @/org/freedesktop/systemd1/notify. sendmsg() fails on such a socket with "Connection refused". The unix(7) man page contains the following details wrt abstract socket addresses abstract: an abstract socket address is distinguished (from a pathname socket) by the fact that sun_path[0] is a null byte ('\0'). The socket's address in this namespace is given by the additional bytes in sun_path that are covered by the specified length of the address structure. (Null bytes in the name have no special significance.) So we need to be more precise about the address length, setting it to the sizeof sa_family_t + length of address copied to sun_path instead of setting it to the sizeof the entire sockaddr_un struct. Resolves: https://bugzilla.opensuse.org/show_bug.cgi?id=987668 Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/util/virsystemd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c index 871db7e..1b5e9fe 100644 --- a/src/util/virsystemd.c +++ b/src/util/virsystemd.c @@ -495,7 +495,6 @@ virSystemdNotifyStartup(void) }; struct msghdr mh = { .msg_name = &un, - .msg_namelen = sizeof(un), .msg_iov = &iov, .msg_iovlen = 1, }; @@ -521,6 +520,7 @@ virSystemdNotifyStartup(void) return; } + mh.msg_namelen = sizeof(sa_family_t) + strlen(path); if (sendmsg(fd, &mh, MSG_NOSIGNAL) < 0) VIR_WARN("Failed to notify systemd"); -- 2.1.4
On Mon, Jul 11, 2016 at 05:35:03PM -0600, Jim Fehlig wrote:
At least with systemd v210, NOTIFY_SOCKET is abstact, e.g. @/org/freedesktop/systemd1/notify. sendmsg() fails on such a socket with "Connection refused". The unix(7) man page contains the following details wrt abstract socket addresses
abstract: an abstract socket address is distinguished (from a pathname socket) by the fact that sun_path[0] is a null byte ('\0'). The socket's address in this namespace is given by the additional bytes in sun_path that are covered by the specified length of the address structure. (Null bytes in the name have no special significance.)
So we need to be more precise about the address length, setting it to the sizeof sa_family_t + length of address copied to sun_path instead of setting it to the sizeof the entire sockaddr_un struct.
Resolves: https://bugzilla.opensuse.org/show_bug.cgi?id=987668 Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/util/virsystemd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c index 871db7e..1b5e9fe 100644 --- a/src/util/virsystemd.c +++ b/src/util/virsystemd.c @@ -495,7 +495,6 @@ virSystemdNotifyStartup(void) }; struct msghdr mh = { .msg_name = &un, - .msg_namelen = sizeof(un), .msg_iov = &iov, .msg_iovlen = 1, }; @@ -521,6 +520,7 @@ virSystemdNotifyStartup(void) return; }
+ mh.msg_namelen = sizeof(sa_family_t) + strlen(path);
I'm wondering how safe sizeof(sa_family_t) is. Might it be better to use offsetof(struct sockaddr_un, sun_path) + strlen(path)
if (sendmsg(fd, &mh, MSG_NOSIGNAL) < 0) VIR_WARN("Failed to notify systemd");
Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
Daniel P. Berrange wrote:
On Mon, Jul 11, 2016 at 05:35:03PM -0600, Jim Fehlig wrote:
At least with systemd v210, NOTIFY_SOCKET is abstact, e.g. @/org/freedesktop/systemd1/notify. sendmsg() fails on such a socket with "Connection refused". The unix(7) man page contains the following details wrt abstract socket addresses
abstract: an abstract socket address is distinguished (from a pathname socket) by the fact that sun_path[0] is a null byte ('\0'). The socket's address in this namespace is given by the additional bytes in sun_path that are covered by the specified length of the address structure. (Null bytes in the name have no special significance.)
So we need to be more precise about the address length, setting it to the sizeof sa_family_t + length of address copied to sun_path instead of setting it to the sizeof the entire sockaddr_un struct.
Resolves: https://bugzilla.opensuse.org/show_bug.cgi?id=987668 Signed-off-by: Jim Fehlig <jfehlig@suse.com> --- src/util/virsystemd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c index 871db7e..1b5e9fe 100644 --- a/src/util/virsystemd.c +++ b/src/util/virsystemd.c @@ -495,7 +495,6 @@ virSystemdNotifyStartup(void) }; struct msghdr mh = { .msg_name = &un, - .msg_namelen = sizeof(un), .msg_iov = &iov, .msg_iovlen = 1, }; @@ -521,6 +520,7 @@ virSystemdNotifyStartup(void) return; }
+ mh.msg_namelen = sizeof(sa_family_t) + strlen(path);
I'm wondering how safe sizeof(sa_family_t) is. Might it be better to use offsetof(struct sockaddr_un, sun_path) + strlen(path)
Yes, I think that is safer. V2 on the way... Regards, Jim
participants (2)
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Daniel P. Berrange -
Jim Fehlig