File 0001-Backport-autodev-fix-from-lxc-master.patch of Package lxc

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File 0001-Backport-autodev-fix-from-lxc-master.patch of Package lxc (Revision 87a97ed8b6e07a7bd216c929b72bbf55)

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From 85ad111c65a5bbeb5586ad12084800c992c1dd9e Mon Sep 17 00:00:00 2001
From: Bernd Wachter <bernd-obs@wachter.fi>
Date: Mon, 27 Aug 2018 10:33:23 +0300
Subject: [PATCH] Backport autodev fix from lxc master

See description of the issue in the initial patch: https://github.com/lxc/lxc/commit/3e04a6083eefe0b837db6d1b826721fd985ce052
---
 src/lxc/conf.c | 92 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 63 insertions(+), 29 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 91816be..7272e25 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1146,12 +1146,20 @@ static const struct lxc_devs lxc_devs[] = {
 	{ "tty",     S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 5, 0 },
 };
 
+enum {
+	LXC_DEVNODE_BIND,
+	LXC_DEVNODE_MKNOD,
+	LXC_DEVNODE_PARTIAL,
+	LXC_DEVNODE_OPEN,
+};
+
 static int lxc_fill_autodev(const struct lxc_rootfs *rootfs)
 {
 	int ret;
 	char path[MAXPATHLEN];
 	int i;
 	mode_t cmask;
+	int use_mknod = LXC_DEVNODE_MKNOD;
 
 	ret = snprintf(path, MAXPATHLEN, "%s/dev",
 		       rootfs->path ? rootfs->mount : "");
@@ -1166,50 +1174,76 @@ static int lxc_fill_autodev(const struct lxc_rootfs *rootfs)
 
 	cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
 	for (i = 0; i < sizeof(lxc_devs) / sizeof(lxc_devs[0]); i++) {
-		const struct lxc_devs *d = &lxc_devs[i];
+		const struct lxc_devs *device = &lxc_devs[i];
+		char hostpath[MAXPATHLEN];
 
 		ret = snprintf(path, MAXPATHLEN, "%s/dev/%s",
-			       rootfs->path ? rootfs->mount : "", d->name);
+			       rootfs->path ? rootfs->mount : "", device->name);
 		if (ret < 0 || ret >= MAXPATHLEN)
 			return -1;
 
-		ret = mknod(path, d->mode, makedev(d->maj, d->min));
-		if (ret < 0) {
-			FILE *pathfile;
-			char hostpath[MAXPATHLEN];
+		if (use_mknod >= LXC_DEVNODE_MKNOD) {
+			ret = mknod(path, device->mode, makedev(device->maj, device->min));
+			if (ret == 0 || (ret < 0 && errno == EEXIST)) {
+				DEBUG("Created device node \"%s\"", path);
+			} else if (ret < 0) {
+				if (errno != EPERM) {
+					SYSERROR("Failed to create device node \"%s\"", path);
+					return -1;
+				}
+
+				use_mknod = LXC_DEVNODE_BIND;
+			}
 
-			if (errno == EEXIST) {
-				DEBUG("\"%s\" device already existed", path);
+			/* Device nodes are fully useable. */
+			if (use_mknod == LXC_DEVNODE_OPEN)
 				continue;
+
+			if (use_mknod == LXC_DEVNODE_MKNOD) {
+				/* See
+				 * - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55956b59df336f6738da916dbb520b6e37df9fbd
+				 * - https://lists.linuxfoundation.org/pipermail/containers/2018-June/039176.html
+				 */
+				ret = open(path, O_RDONLY | O_CLOEXEC);
+				if (ret >= 0) {
+					close(ret);
+					/* Device nodes are fully useable. */
+					use_mknod = LXC_DEVNODE_OPEN;
+					continue;
+				}
+
+				SYSERROR("Failed to open \"%s\" device", path);
+				/* Device nodes are only partially useable. */
+				use_mknod = LXC_DEVNODE_PARTIAL;
 			}
+		}
 
-			/* Unprivileged containers cannot create devices, so
-			 * bind mount the device from the host.
+		if (use_mknod != LXC_DEVNODE_PARTIAL) {
+			/* If we are dealing with partially functional device
+			 * nodes the prio mknod() call will have created the
+			 * device node so we can use it as a bind-mount target.
 			 */
-			ret = snprintf(hostpath, MAXPATHLEN, "/dev/%s", d->name);
-			if (ret < 0 || ret >= MAXPATHLEN)
-				return -1;
-
-			pathfile = fopen(path, "wb");
-			if (!pathfile) {
+			ret = mknod(path, S_IFREG | 0000, 0);
+			if (ret < 0 && errno != EEXIST) {
 				SYSERROR("Failed to create file \"%s\"", path);
 				return -1;
 			}
-			fclose(pathfile);
+		}
 
-			ret = safe_mount(hostpath, path, 0, MS_BIND, NULL,
-					 rootfs->path ? rootfs->mount : NULL);
-			if (ret < 0) {
-				SYSERROR("Failed to bind mount \"%s\" from "
-					 "host into container",
-					 d->name);
-				return -1;
-			}
-			DEBUG("Bind mounted \"%s\" onto \"%s\"", hostpath,
-			      path);
-		} else {
-			DEBUG("Created device node \"%s\"", path);
+		/* Fallback to bind-mounting the device from the host. */
+		ret = snprintf(hostpath, MAXPATHLEN, "/dev/%s", device->name);
+		if (ret < 0 || ret >= MAXPATHLEN)
+			return -1;
+
+		ret = safe_mount(hostpath, path, 0, MS_BIND, NULL,
+				 rootfs->path ? rootfs->mount : NULL);
+		if (ret < 0) {
+			SYSERROR("Failed to bind mount host device node \"%s\" "
+				 "onto \"%s\"", hostpath, path);
+			return -1;
 		}
+		DEBUG("Bind mounted host device node \"%s\" onto \"%s\"",
+		      hostpath, path);
 	}
 	umask(cmask);
 
-- 
2.18.0

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File 0001-Backport-autodev-fix-from-lxc-master.patch of Package lxc (Revision 87a97ed8b6e07a7bd216c929b72bbf55)

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