Fix annoying "permission denied" when saving running-config

board/common/rootfs/usr/bin/dir

@@ -21,7 +21,11 @@ dir()
 if [ -d "$1" ]; then
     dir "$1"
 else
-    dir "$HOME"
+    if [ "$USER" = "root" ]; then
+	dir "$HOME"
+    else
+	dir "/home/$USER"
+    fi
     dir "/cfg"
     dir "/log"
 fi

doc/ChangeLog.md

@@ -31,6 +31,8 @@ All notable changes to the project are documented in this file.
  - Fix #956: CLI `copy` command complains it cannot change owner when
    copying `factory-config` to `running-config`.  Bogus error, the
    latter is not really a file
+ - Fix #977: "Operation not permitted" when saving `running-config` to
+   `startup-config` (harmless warning but annoying and concerning)
 
 [EVK]: https://www.nxp.com/design/design-center/development-boards-and-designs/8MPLUSLPD4-EVK
 

src/bin/copy.c

@@ -3,6 +3,7 @@
 
 #include <getopt.h>
 #include <pwd.h>
+#include <grp.h>
 #include <stdio.h>
 #include <stdarg.h>
 
@@ -23,11 +24,11 @@ struct infix_ds {
 };
 
 struct infix_ds infix_config[] = {
-	{ "startup-config",     "startup",     SR_DS_STARTUP,         1, "/cfg/startup-config.cfg" },
-	{ "running-config",     "running",     SR_DS_RUNNING,         1, NULL },
-	{ "candidate-config",   "candidate",   SR_DS_CANDIDATE,       1, NULL },
-	{ "operational-config", "operational", SR_DS_OPERATIONAL,     1, NULL },
-	{ "factory-config",     "factory-default",          SR_DS_FACTORY_DEFAULT, 0, NULL }
+	{ "startup-config",     "startup",          SR_DS_STARTUP,         1, "/cfg/startup-config.cfg" },
+	{ "running-config",     "running",          SR_DS_RUNNING,         1, NULL },
+	{ "candidate-config",   "candidate",        SR_DS_CANDIDATE,       1, NULL },
+	{ "operational-config", "operational",      SR_DS_OPERATIONAL,     1, NULL },
+	{ "factory-config",     "factory-default",  SR_DS_FACTORY_DEFAULT, 0, NULL }
 };
 
 static const char *prognm = "copy";
@@ -64,6 +65,9 @@ static void emsg(sr_session_ctx_t *sess, const char *fmt, ...)
 	}
 }
 
+/*
+ * Current system user, same as sysrepo user
+ */
 static char *getuser(void)
 {
 	const struct passwd *pw;
@@ -79,18 +83,87 @@ static char *getuser(void)
 	return pw->pw_name;
 }
 
+/*
+ * If UNIX user is in UNIX group of directory containing file,
+ * return gid, otherwise -1
+ *
+ * E.g., writing to /cfg/foo, where /cfg is owned by root:wheel,
+ * should result in the file being owned by $LOGNAME:wheel with
+ * 0660 perms for other users in same group.
+ */
+static gid_t in_group(const char *user, const char *fn, gid_t *gid)
+{
+	char dir[strlen(fn) + 2];
+	const struct passwd *pw;
+	int i, num = 0, rc = 0;
+	struct stat st;
+	gid_t *groups;
+	char *ptr;
+
+	pw = getpwnam(user);
+	if (!pw)
+		return 0;
+
+	strlcpy(dir, fn, sizeof(dir));
+	ptr = strrchr(dir, '/');
+	if (ptr)
+		*ptr = 0;
+	else
+		strlcpy(dir, ".", sizeof(dir));
+
+	if (stat(dir, &st))
+		return 0;
+
+	getgrouplist(user, pw->pw_gid, NULL, &num);
+
+	groups = malloc(num * sizeof(gid_t));
+	if (!groups) {
+		perror("in_group() malloc");
+		return 0;
+	}
+
+	getgrouplist(user, pw->pw_gid, groups, &num);
+	for (i = 0; i < num; i++) {
+		if (groups[i] == st.st_gid) {
+			*gid = st.st_gid;
+			rc = 1;
+			break;
+		}
+	}
+	free(groups);
+
+	return rc;
+}
+
+/*
+ * Set group owner so other users with same directory permissions can
+ * read/write the file as well.  E.g., an 'admin' level user in group
+ * 'wheel' writing a new file to `/cfg` should be possible to read and
+ * write to by other administrators.
+ *
+ * This function is called only when the file has been successfully
+ * copied or created in a file system directory.  This is why we can
+ * safely ignore any EPERM errors to chown(), below, because if the file
+ * already existed, created by another user, we are not allowed to chgrp
+ * it.  The sole purpose of this function is to allow other users in the
+ * same group to access the file in the future.
+ */
 static void set_owner(const char *fn, const char *user)
 {
-	struct passwd *pw;
+	gid_t gid = 9999;
 
 	if (!fn)
 		return;	/* not an error, e.g., running-config is not a file */
 
-	pw = getpwnam(user);
-	if (pw && !chmod(fn, 0660) && !chown(fn, pw->pw_uid, pw->pw_gid))
-		return;
+	if (!in_group(user, fn, &gid))
+		return;	/* user not in parent directory's group */
+
+	if (chown(fn, -1, gid) && errno != EPERM) {
+		const struct group *gr = getgrgid(gid);
 
-	fprintf(stderr, ERRMSG "setting owner %s on %s: %s\n", user, fn, strerror(errno));
+		fprintf(stderr, ERRMSG "setting group owner %s (%d) on %s: %s\n",
+			gr ? gr->gr_name : "<unknown>", gid, fn, strerror(errno));
+	}
 }
 
 static const char *infix_ds(const char *text, struct infix_ds **ds)
@@ -108,20 +181,21 @@ static const char *infix_ds(const char *text, struct infix_ds **ds)
 }
 
 
-static int copy(const char *src, const char *dst, const char *user)
+static int copy(const char *src, const char *dst, const char *remote_user)
 {
 	struct infix_ds *srcds = NULL, *dstds = NULL;
 	char temp_file[20] = "/tmp/copy.XXXXXX";
 	const char *tmpfn = NULL;
 	sr_session_ctx_t *sess;
 	const char *fn = NULL;
-	const char *username;
 	sr_conn_ctx_t *conn;
+	const char *user;
 	char adjust[256];
 	mode_t oldmask;
 	int rc = 0;
 
-	oldmask = umask(0660);
+	/* rw for user and group only */
+	oldmask = umask(0006);
 
 	src = infix_ds(src, &srcds);
 	if (!src)
@@ -135,7 +209,7 @@ static int copy(const char *src, const char *dst, const char *user)
 		goto err;
 	}
 
-	username = getuser();
+	user = getuser();
 
 	/* 1. Regular ds copy */
 	if (srcds && dstds) {
@@ -157,13 +231,13 @@ static int copy(const char *src, const char *dst, const char *user)
 		if (sr_session_start(conn, dstds->datastore, &sess)) {
 			fprintf(stderr, ERRMSG "unable to open transaction to %s\n", dst);
 		} else {
-			sr_nacm_set_user(sess, username);
+			sr_nacm_set_user(sess, user);
 			rc = sr_copy_config(sess, NULL, srcds->datastore, timeout * 1000);
 			if (rc)
 				emsg(sess, ERRMSG "unable to copy configuration, err %d: %s\n",
 				     rc, sr_strerror(rc));
 			else
-				set_owner(dstds->path, username);
+				set_owner(dstds->path, user);
 		}
 		rc = sr_disconnect(conn);
 
@@ -187,11 +261,11 @@ static int copy(const char *src, const char *dst, const char *user)
 			if (rc)
 				fprintf(stderr, ERRMSG "failed exporting %s to %s\n", src, fn);
 			else {
-				rc = systemf("curl %s -LT %s %s", user, fn, dst);
+				rc = systemf("curl %s -LT %s %s", remote_user, fn, dst);
 				if (rc)
 					fprintf(stderr, ERRMSG "failed uploading %s to %s\n", src, dst);
 				else
-					set_owner(dst, username);
+					set_owner(dst, user);
 			}
 			goto err;
 		}
@@ -219,7 +293,7 @@ static int copy(const char *src, const char *dst, const char *user)
 		if (rc)
 			fprintf(stderr, ERRMSG "failed copy %s to %s\n", src, fn);
 		else
-			set_owner(fn, username);
+			set_owner(fn, user);
 	} else if (dstds) {
 		if (!dstds->sysrepocfg) {
 			fprintf(stderr, ERRMSG "not possible to import to this datastore.\n");
@@ -245,7 +319,7 @@ static int copy(const char *src, const char *dst, const char *user)
 		}
 
 		if (tmpfn)
-			rc = systemf("curl %s -Lo %s %s", user, fn, src);
+			rc = systemf("curl %s -Lo %s %s", remote_user, fn, src);
 		if (rc) {
 			fprintf(stderr, ERRMSG "failed downloading %s", src);
 		} else {
@@ -274,7 +348,7 @@ static int copy(const char *src, const char *dst, const char *user)
 				}
 			}
 
-			rc = systemf("curl %s -Lo %s %s", user, fn, src);
+			rc = systemf("curl %s -Lo %s %s", remote_user, fn, src);
 		} else if (strstr(dst, "://")) {
 			fn = cfg_adjust(src, NULL, adjust, sizeof(adjust));
 			if (!fn) {
@@ -286,7 +360,7 @@ static int copy(const char *src, const char *dst, const char *user)
 			if (access(fn, F_OK))
 				fprintf(stderr, ERRMSG "no such file %s, aborting.", fn);
 			else
-				rc = systemf("curl %s -LT %s %s", user, fn, dst);
+				rc = systemf("curl %s -LT %s %s", remote_user, fn, dst);
 		} else {
 			if (!access(dst, F_OK)) {
 				if (!yorn("Overwrite existing file %s", dst)) {

src/bin/files.c

@@ -28,6 +28,10 @@ int files(const char *path, const char *stripext)
 		if (d->d_type != DT_REG || d->d_name[0] == '.')
 			continue;
 
+		/* skip startup in /cfg, listed by plugin */
+		if (!strcmp(path, "/cfg") && !strcmp(d->d_name, "startup-config.cfg"))
+			continue;
+
 		strlcpy(name, d->d_name, sizeof(name));
 		if (stripext) {
 			size_t pos = has_ext(name, stripext);

src/klish-plugin-infix/src/infix.c

@@ -102,7 +102,7 @@ int infix_datastore(kcontext_t *ctx)
 	}
 
 done:
-	return systemf("files /cfg .cfg");
+	return systemf("files /cfg");
 }
 
 int infix_erase(kcontext_t *ctx)