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authorLennart Poettering <lennart@poettering.net>2016-10-06 15:48:15 +0200
committerLennart Poettering <lennart@poettering.net>2016-10-06 19:04:01 +0200
commit429b43502675550ed61d3f62a4ffd295ab10732d (patch)
treebbbe9e1f7f9573bf14b6508a31c27a1307d59f7c
parentd21494ea25a5f36af998191a7d86adc2fe511638 (diff)
sd-device/networkd: unify code to get a socket for issuing netdev ioctls on
As suggested here: https://github.com/systemd/systemd/pull/4296#issuecomment-251911349 Let's try AF_INET first as socket, but let's fall back to AF_NETLINK, so that we can use a protocol-independent socket here if possible. This has the benefit that our code will still work even if AF_INET/AF_INET6 is made unavailable (for exmple via seccomp), at least on current kernels.
-rw-r--r--src/basic/socket-util.c17
-rw-r--r--src/basic/socket-util.h2
-rw-r--r--src/libsystemd/sd-device/sd-device.c5
-rw-r--r--src/udev/net/ethtool-util.c6
4 files changed, 25 insertions, 5 deletions
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 5c829e0e7e..1662c04705 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -1060,3 +1060,20 @@ struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t leng
return NULL;
}
+
+int socket_ioctl_fd(void) {
+ int fd;
+
+ /* Create a socket to invoke the various network interface ioctl()s on. Traditionally only AF_INET was good for
+ * that. Since kernel 4.6 AF_NETLINK works for this too. We first try to use AF_INET hence, but if that's not
+ * available (for example, because it is made unavailable via SECCOMP or such), we'll fall back to the more
+ * generic AF_NETLINK. */
+
+ fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ fd = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_GENERIC);
+ if (fd < 0)
+ return -errno;
+
+ return fd;
+}
diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h
index 2536b085f9..2ef572badb 100644
--- a/src/basic/socket-util.h
+++ b/src/basic/socket-util.h
@@ -154,3 +154,5 @@ struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t leng
1 + strnlen(_sa->sun_path+1, sizeof(_sa->sun_path)-1) : \
strnlen(_sa->sun_path, sizeof(_sa->sun_path))); \
})
+
+int socket_ioctl_fd(void);
diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c
index 0c4ad966bd..411453e08d 100644
--- a/src/libsystemd/sd-device/sd-device.c
+++ b/src/libsystemd/sd-device/sd-device.c
@@ -36,6 +36,7 @@
#include "parse-util.h"
#include "path-util.h"
#include "set.h"
+#include "socket-util.h"
#include "stat-util.h"
#include "string-util.h"
#include "strv.h"
@@ -629,9 +630,9 @@ _public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
if (r < 0)
return r;
- sk = socket(PF_INET, SOCK_DGRAM, 0);
+ sk = socket_ioctl_fd();
if (sk < 0)
- return -errno;
+ return sk;
r = ioctl(sk, SIOCGIFNAME, &ifr);
if (r < 0)
diff --git a/src/udev/net/ethtool-util.c b/src/udev/net/ethtool-util.c
index b1aa0223fd..708a665576 100644
--- a/src/udev/net/ethtool-util.c
+++ b/src/udev/net/ethtool-util.c
@@ -25,6 +25,7 @@
#include "conf-parser.h"
#include "ethtool-util.h"
#include "log.h"
+#include "socket-util.h"
#include "string-table.h"
#include "strxcpyx.h"
#include "util.h"
@@ -59,10 +60,9 @@ int ethtool_connect(int *ret) {
assert_return(ret, -EINVAL);
- fd = socket(PF_INET, SOCK_DGRAM, 0);
+ fd = socket_ioctl_fd();
if (fd < 0)
- return -errno;
-
+ return fd;
*ret = fd;
return 0;