| Message ID | 20171020092844.13880-1-berrange@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | sockets: avoid leak of listen file descriptor | expand |
On Fri, Oct 20, 2017 at 10:28:44AM +0100, Daniel P. Berrange wrote: > If we iterate over the full port range without successfully binding+listening > on the socket, we'll try the next address, whereupon we overwrite the slisten > file descriptor variable without closing it. > > Rather than having two places where we open + close socket FDs on different > iterations of nested for loops, re-arrange the code to always open+close > within the same loop iteration. > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > util/qemu-sockets.c | 31 +++++++++++++++++++------------ > 1 file changed, 19 insertions(+), 12 deletions(-) Self-NACK this has a bug too Regards, Daniel
Hi Daniel, On Fri, Oct 20, 2017 at 10:28:44AM +0100, Daniel P. Berrange wrote: >If we iterate over the full port range without successfully binding+listening >on the socket, we'll try the next address, whereupon we overwrite the slisten >file descriptor variable without closing it. > >Rather than having two places where we open + close socket FDs on different >iterations of nested for loops, re-arrange the code to always open+close >within the same loop iteration. > >Signed-off-by: Daniel P. Berrange <berrange@redhat.com> >--- > util/qemu-sockets.c | 31 +++++++++++++++++++------------ > 1 file changed, 19 insertions(+), 12 deletions(-) > >diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c >index b47fb45885..a319338cca 100644 >--- a/util/qemu-sockets.c >+++ b/util/qemu-sockets.c >@@ -207,7 +207,7 @@ static int inet_listen_saddr(InetSocketAddress *saddr, > char uaddr[INET6_ADDRSTRLEN+1]; > char uport[33]; > int rc, port_min, port_max, p; >- int slisten = 0; >+ int slisten = -1; > int saved_errno = 0; > bool socket_created = false; > Error *err = NULL; >@@ -267,16 +267,28 @@ static int inet_listen_saddr(InetSocketAddress *saddr, > uaddr,INET6_ADDRSTRLEN,uport,32, > NI_NUMERICHOST | NI_NUMERICSERV); > >- slisten = create_fast_reuse_socket(e); >- if (slisten < 0) { >- continue; >- } >- > socket_created = true; Is this setting of socket_created correct now? Maybe it should be moved to before the try_bind() below? > port_min = inet_getport(e); > port_max = saddr->has_to ? saddr->to + port_offset : port_min; > for (p = port_min; p <= port_max; p++) { > inet_setport(e, p); >+ >+ slisten = create_fast_reuse_socket(e); >+ if (slisten < 0) { >+ /* First time we expect we might fail to create the socket >+ * eg if 'e' has AF_INET6 but ipv6 kmod is not loaded. >+ * Later iterations should always succeeed if first iteration >+ * worked though, so treat that as fatal. >+ */ >+ if (p == port_min) { >+ continue; >+ } else { >+ error_setg_errno(errp, errno, >+ "Failed to recreate failed listening socket"); >+ goto listen_failed; >+ } >+ } >+ > rc = try_bind(slisten, saddr, e); > if (rc) { > if (errno == EADDRINUSE) { >@@ -299,12 +311,7 @@ static int inet_listen_saddr(InetSocketAddress *saddr, > * socket to allow bind attempts for subsequent ports: > */ > closesocket(slisten); >- slisten = create_fast_reuse_socket(e); >- if (slisten < 0) { >- error_setg_errno(errp, errno, >- "Failed to recreate failed listening socket"); >- goto listen_failed; >- } >+ slisten = -1; > } > } > error_setg_errno(errp, errno, Thanks, Darren.
On Fri, Oct 20, 2017 at 10:54:31AM +0100, Daniel P. Berrange wrote: >On Fri, Oct 20, 2017 at 10:28:44AM +0100, Daniel P. Berrange wrote: >> If we iterate over the full port range without successfully binding+listening >> on the socket, we'll try the next address, whereupon we overwrite the slisten >> file descriptor variable without closing it. >> >> Rather than having two places where we open + close socket FDs on different >> iterations of nested for loops, re-arrange the code to always open+close >> within the same loop iteration. >> >> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> >> --- >> util/qemu-sockets.c | 31 +++++++++++++++++++------------ >> 1 file changed, 19 insertions(+), 12 deletions(-) > >Self-NACK this has a bug too Missed this... Darren. > > >Regards, >Daniel >-- >|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| >|: https://libvirt.org -o- https://fstop138.berrange.com :| >|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| >
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index b47fb45885..a319338cca 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -207,7 +207,7 @@ static int inet_listen_saddr(InetSocketAddress *saddr, char uaddr[INET6_ADDRSTRLEN+1]; char uport[33]; int rc, port_min, port_max, p; - int slisten = 0; + int slisten = -1; int saved_errno = 0; bool socket_created = false; Error *err = NULL; @@ -267,16 +267,28 @@ static int inet_listen_saddr(InetSocketAddress *saddr, uaddr,INET6_ADDRSTRLEN,uport,32, NI_NUMERICHOST | NI_NUMERICSERV); - slisten = create_fast_reuse_socket(e); - if (slisten < 0) { - continue; - } - socket_created = true; port_min = inet_getport(e); port_max = saddr->has_to ? saddr->to + port_offset : port_min; for (p = port_min; p <= port_max; p++) { inet_setport(e, p); + + slisten = create_fast_reuse_socket(e); + if (slisten < 0) { + /* First time we expect we might fail to create the socket + * eg if 'e' has AF_INET6 but ipv6 kmod is not loaded. + * Later iterations should always succeeed if first iteration + * worked though, so treat that as fatal. + */ + if (p == port_min) { + continue; + } else { + error_setg_errno(errp, errno, + "Failed to recreate failed listening socket"); + goto listen_failed; + } + } + rc = try_bind(slisten, saddr, e); if (rc) { if (errno == EADDRINUSE) { @@ -299,12 +311,7 @@ static int inet_listen_saddr(InetSocketAddress *saddr, * socket to allow bind attempts for subsequent ports: */ closesocket(slisten); - slisten = create_fast_reuse_socket(e); - if (slisten < 0) { - error_setg_errno(errp, errno, - "Failed to recreate failed listening socket"); - goto listen_failed; - } + slisten = -1; } } error_setg_errno(errp, errno,
If we iterate over the full port range without successfully binding+listening on the socket, we'll try the next address, whereupon we overwrite the slisten file descriptor variable without closing it. Rather than having two places where we open + close socket FDs on different iterations of nested for loops, re-arrange the code to always open+close within the same loop iteration. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- util/qemu-sockets.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-)