From: Daniel Golle <daniel@makrotopia.org>
Date: Wed, 14 Jul 2021 16:47:22 +0000 (+0100)
Subject: jail: allow rootfs to be a symbolic link
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=15997e67a559d3477d34613062725689fbfeab93;p=project%2Fprocd.git

jail: allow rootfs to be a symbolic link

Follow symbolic link to rootfs so we can use autofs symlinks in /mnt
to reference volumes in config.json.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---

diff --git a/jail/jail.c b/jail/jail.c
index b8878b5..dca3992 100644
--- a/jail/jail.c
+++ b/jail/jail.c
@@ -1325,6 +1325,8 @@ static const struct blobmsg_policy oci_root_policy[] = {
 static int parseOCIroot(const char *jsonfile, struct blob_attr *msg)
 {
 	static char extroot[PATH_MAX] = { 0 };
+	char buf[PATH_MAX];
+	ssize_t len;
 	struct blob_attr *tb[__OCI_ROOT_MAX];
 	char *cur;
 	char *root_path;
@@ -1349,6 +1351,21 @@ static int parseOCIroot(const char *jsonfile, struct blob_attr *msg)
 
 	strncat(extroot, root_path, PATH_MAX - (strlen(extroot) + 1));
 
+	/* follow symbolic link(s) */
+	while ((len = readlink(extroot, buf, sizeof(buf)-1)) != -1) {
+		buf[len] = '\0';
+		if (buf[0] != '/') {
+			cur = strrchr(extroot, '/');
+			if (!cur)
+				return ENOTDIR;
+
+			*(++cur) = '\0';
+			strncat(extroot, buf, sizeof(extroot)-1);
+		} else {
+			strncpy(extroot, buf, sizeof(extroot)-1);
+		}
+	}
+
 	opts.extroot = extroot;
 
 	if (tb[OCI_ROOT_READONLY])