Linux: detect network namespace and deny udev in one

udev says whether an interface name is stable or not.
In a network namespace, udev claims the interface does not exist.
This makes sense because udev only operates in the root namespace.

As such disable udev in a network namespace.

While here correctly spell initialise.

9 files changed, 61 insertions, 12 deletions

diff --git a/src/dev.c b/src/dev.c
index f7da67e4..8f14bf6b 100644
--- a/src/dev.c
+++ b/src/dev.c
@@ -39,18 +39,18 @@
 #include "logerr.h"
 
 int
-dev_initialized(struct dhcpcd_ctx *ctx, const char *ifname)
+dev_initialised(struct dhcpcd_ctx *ctx, const char *ifname)
 {
 
 #ifdef PRIVSEP
 	if (ctx->options & DHCPCD_PRIVSEP &&
 	    !(ctx->options & DHCPCD_PRIVSEPROOT))
-		return ps_root_dev_initialized(ctx, ifname);
+		return ps_root_dev_initialised(ctx, ifname);
 #endif
 
 	if (ctx->dev == NULL)
 		return 1;
-	return ctx->dev->initialized(ifname);
+	return ctx->dev->initialised(ifname);
 }
 
 int
diff --git a/src/dev.h b/src/dev.h
index d51cbbec..3bfb5729 100644
--- a/src/dev.h
+++ b/src/dev.h
@@ -31,7 +31,7 @@
 // dev plugin setup
 struct dev {
 	const char *name;
-	int (*initialized)(const char *);
+	int (*initialised)(const char *);
 	int (*listening)(void);
 	int (*handle_device)(void *);
 	int (*start)(void);
@@ -47,7 +47,7 @@ int dev_init(struct dev *, const struct dev_dhcpcd *);
 // hooks for dhcpcd
 #ifdef PLUGIN_DEV
 #include "dhcpcd.h"
-int dev_initialized(struct dhcpcd_ctx *, const char *);
+int dev_initialised(struct dhcpcd_ctx *, const char *);
 int dev_listening(struct dhcpcd_ctx *);
 int dev_start(struct dhcpcd_ctx *, int (*)(void *, int, const char *));
 void dev_stop(struct dhcpcd_ctx *);
diff --git a/src/dev/udev.c b/src/dev/udev.c
index 4fe7dde4..fefdefb2 100644
--- a/src/dev/udev.c
+++ b/src/dev/udev.c
@@ -39,6 +39,7 @@
 
 #include "../common.h"
 #include "../dev.h"
+#include "../if.h"
 #include "../logerr.h"
 
 static const char udev_name[] = "udev";
@@ -55,7 +56,7 @@ udev_listening(void)
 }
 
 static int
-udev_initialized(const char *ifname)
+udev_initialised(const char *ifname)
 {
 	struct udev_device *device;
 	int r;
@@ -120,8 +121,14 @@ udev_stop(void)
 static int
 udev_start(void)
 {
+	char netns[PATH_MAX];
 	int fd;
 
+	if (if_getnetworknamespace(netns, sizeof(netns)) != NULL) {
+		logdebugx("udev does not work in a network namespace");
+		return -1;
+	}
+
 	if (udev) {
 		logerrx("udev: already started");
 		return -1;
@@ -167,7 +174,7 @@ dev_init(struct dev *dev, const struct dev_dhcpcd *dev_dhcpcd)
 {
 
 	dev->name = udev_name;
-	dev->initialized = udev_initialized;
+	dev->initialised = udev_initialised;
 	dev->listening = udev_listening;
 	dev->handle_device = udev_handle_device;
 	dev->stop = udev_stop;
diff --git a/src/dhcpcd.h b/src/dhcpcd.h
index 03449e58..0cf774ce 100644
--- a/src/dhcpcd.h
+++ b/src/dhcpcd.h
@@ -254,6 +254,10 @@ struct dhcpcd_ctx {
 	struct dev *dev;
 	void *dev_handle;
 #endif
+
+#ifdef __linux__
+	char netns[PATH_MAX];
+#endif
 };
 
 #ifdef USE_SIGNALS
diff --git a/src/if-linux.c b/src/if-linux.c
index 8d87d748..759b878e 100644
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -60,6 +60,7 @@
 #include <linux/if_arp.h>
 #endif
 
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <ctype.h>
@@ -144,6 +145,7 @@ struct priv {
 	int route_fd;
 	int generic_fd;
 	uint32_t route_pid;
+	char netns[PATH_MAX];
 };
 
 /* We need this to send a broadcast for InfiniBand.
@@ -383,6 +385,36 @@ if_linksocket(struct sockaddr_nl *nl, int protocol, int flags)
 	return fd;
 }
 
+char *
+if_getnetworknamespace(char *buf, size_t len)
+{
+	struct stat sb_self, sb_netns;
+	DIR *dir;
+	struct dirent *de;
+	char file[PATH_MAX], *bufp = NULL;
+
+	if (stat("/proc/self/ns/net", &sb_self) == -1)
+		return NULL;
+
+	dir = opendir("/var/run/netns");
+	if (dir == NULL)
+		return NULL;
+
+	while ((de = readdir(dir)) != NULL) {
+		snprintf(file, sizeof(file), "/var/run/netns/%s", de->d_name);
+		if (stat(file, &sb_netns) == -1)
+			continue;
+		if (sb_self.st_dev != sb_netns.st_dev &&
+		    sb_self.st_ino != sb_netns.st_ino)
+			continue;
+		strlcpy(buf, de->d_name, len);
+		bufp = buf;
+		break;
+	}
+	closedir(dir);
+	return bufp;
+}
+
 int
 if_opensockets_os(struct dhcpcd_ctx *ctx)
 {
@@ -433,6 +465,9 @@ if_opensockets_os(struct dhcpcd_ctx *ctx)
 	if (priv->generic_fd == -1)
 		return -1;
 
+	if (if_getnetworknamespace(ctx->netns, sizeof(ctx->netns)) != NULL)
+		logdebugx("network namespace: %s", ctx->netns);
+
 	return 0;
 }
 
@@ -1614,7 +1649,6 @@ if_initrt(struct dhcpcd_ctx *ctx, rb_tree_t *kroutes, int af)
 	    &_if_initrt, kroutes);
 }
 
-
 #ifdef INET
 /* Linux is a special snowflake when it comes to BPF. */
 const char *bpf_name = "Packet Socket";
diff --git a/src/if.c b/src/if.c
index 40fdadcf..cb407e19 100644
--- a/src/if.c
+++ b/src/if.c
@@ -519,8 +519,11 @@ if_discover(struct dhcpcd_ctx *ctx, struct ifaddrs **ifaddrs,
 
 #ifdef PLUGIN_DEV
 		/* Ensure that the interface name has settled */
-		if (!dev_initialized(ctx, spec.devname))
+		if (!dev_initialised(ctx, spec.devname)) {
+			logdebugx("%s: waiting for interface to initialise",
+			    spec.devname);
 			continue;
+		}
 #endif
 
 		if (if_vimaster(ctx, spec.devname) == 1) {
diff --git a/src/if.h b/src/if.h
index e053fe5b..803f5818 100644
--- a/src/if.h
+++ b/src/if.h
@@ -191,6 +191,7 @@ int if_ignoregroup(int, const char *);
 bool if_ignore(struct dhcpcd_ctx *, const char *);
 int if_vimaster(struct dhcpcd_ctx *ctx, const char *);
 unsigned short if_vlanid(const struct interface *);
+char * if_getnetworknamespace(char *, size_t);
 int if_opensockets(struct dhcpcd_ctx *);
 int if_opensockets_os(struct dhcpcd_ctx *);
 void if_closesockets(struct dhcpcd_ctx *);
diff --git a/src/privsep-root.c b/src/privsep-root.c
index 1a438b67..92faec4c 100644
--- a/src/privsep-root.c
+++ b/src/privsep-root.c
@@ -570,7 +570,7 @@ ps_root_recvmsgcb(void *arg, struct ps_msghdr *psm, struct msghdr *msg)
 #endif
 #ifdef PLUGIN_DEV
 	case PS_DEV_INITTED:
-		err = dev_initialized(ctx, data);
+		err = dev_initialised(ctx, data);
 		break;
 	case PS_DEV_LISTENING:
 		err = dev_listening(ctx);
@@ -989,7 +989,7 @@ ps_root_getauthrdm(struct dhcpcd_ctx *ctx, uint64_t *rdm)
 
 #ifdef PLUGIN_DEV
 int
-ps_root_dev_initialized(struct dhcpcd_ctx *ctx, const char *ifname)
+ps_root_dev_initialised(struct dhcpcd_ctx *ctx, const char *ifname)
 {
 
 	if (ps_sendcmd(ctx, ctx->ps_root_fd, PS_DEV_INITTED, 0,
diff --git a/src/privsep-root.h b/src/privsep-root.h
index 5d6e1248..146622b1 100644
--- a/src/privsep-root.h
+++ b/src/privsep-root.h
@@ -67,7 +67,7 @@ ssize_t ps_root_sendnetlink(struct dhcpcd_ctx *, int, struct msghdr *);
 #endif
 
 #ifdef PLUGIN_DEV
-int ps_root_dev_initialized(struct dhcpcd_ctx *, const char *);
+int ps_root_dev_initialised(struct dhcpcd_ctx *, const char *);
 int ps_root_dev_listening(struct dhcpcd_ctx *);
 #endif