First commit

Signed-off-by: Mattias Andrée <m@maandree.se>

7 files changed, 344 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..9b9a5e7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+*\#*
+*~
+*.o
+*.a
+*.lo
+*.su
+*.so
+*.so.*
+*.dll
+*.dylib
+*.gch
+*.gcov
+*.gcno
+*.gcda
+/nokeyrings
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..0e6be1c
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,15 @@
+ISC License
+
+© 2025 Mattias Andrée <m@maandree.se>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..f691e40
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,41 @@
+.POSIX:
+
+CONFIGFILE = config.mk
+include $(CONFIGFILE)
+
+OBJ =\
+	nokeyrings.o
+
+HDR =
+
+all: nokeyrings
+$(OBJ): $(HDR)
+
+.c.o:
+	$(CC) -c -o $@ $< $(CFLAGS) $(CPPFLAGS)
+
+nokeyrings: $(OBJ)
+	$(CC) -o $@ $(OBJ) $(LDFLAGS)
+
+install: nokeyrings
+	mkdir -p -- "$(DESTDIR)$(PREFIX)/bin"
+	mkdir -p -- "$(DESTDIR)$(MANPREFIX)/man1/"
+	cp -- nokeyrings "$(DESTDIR)$(PREFIX)/bin/"
+	cp -- nokeyrings.1 "$(DESTDIR)$(MANPREFIX)/man1/"
+
+post-install:
+	chown -- '0:0' "$(DESTDIR)$(PREFIX)/bin/nokeyrings"
+	chmod -- 4755 "$(DESTDIR)$(PREFIX)/bin/nokeyrings"
+
+uninstall:
+	-rm -f -- "$(DESTDIR)$(PREFIX)/bin/nokeyrings"
+	-rm -f -- "$(DESTDIR)$(MANPREFIX)/man1/nokeyrings.1"
+
+clean:
+	-rm -f -- *.o *.a *.lo *.su *.so *.so.* *.gch *.gcov *.gcno *.gcda
+	-rm -f -- nokeyrings
+
+.SUFFIXES:
+.SUFFIXES: .o .c
+
+.PHONY: all install post-install uninstall clean
diff --git a/README b/README
new file mode 100644
index 0000000..4a00228
--- /dev/null
+++ b/README
@@ -0,0 +1,42 @@
+NAME
+	nokeyrings - Spawn a new program and hide the user's keyrings from it
+
+SYNOPSIS
+	nokeyrings utility [argument] ...
+
+DESCRIPTION
+	The nokeyrings utility runs a specified utility, but mounts
+	/var/empty over ~/.local/share/keyrings, if both directories
+	exist, (failure is ignored) for that process and its children,
+	effectively hiding the
+	user's keyrings.
+
+OPTIONS
+	No options are supported.
+
+OPERANDS
+	The following operands are supported:
+
+	utility
+		The name of the utility to be invoked.
+
+	argument
+		A string to pass as an argument for the invoked utility.
+
+EXIT STATUS
+	If utility is invoked, the exit status of nokeyrings is the exit
+	status of utility; otherwise, the nokeyrings utility exits with
+	one of the following values:
+
+	125     An error occurred in the nokeyrings utility.
+
+	126	The utility specified by utility was found but could
+		not be invoked.
+
+	127	The utility sspecified by utility could not be found.
+
+RATIONALE
+	The nokeyrings utility can be used as a wrapper around programs
+	that nags the user about entering his password to access a
+	keyring, if he does it use it but the keyring is tightly
+	integrated into the OS distribution and cannot easily be removed.
diff --git a/config.mk b/config.mk
new file mode 100644
index 0000000..aeb8cec
--- /dev/null
+++ b/config.mk
@@ -0,0 +1,8 @@
+PREFIX    = /usr
+MANPREFIX = $(PREFIX)/share/man
+
+CC = c99
+
+CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
+CFLAGS   =
+LDFLAGS  = -lsimple
diff --git a/nokeyrings.1 b/nokeyrings.1
new file mode 100644
index 0000000..984b7d8
--- /dev/null
+++ b/nokeyrings.1
@@ -0,0 +1,96 @@
+.TH NOKEYRINGS 1 NOKEYRINGS
+.SH NAME
+nokeyrings - Spawn a new program and hide the user's keyrings from it
+
+.SH SYNOPSIS
+.B nokeyrings
+.I utility
+.RI [ argument "] ..."
+
+.SH DESCRIPTION
+The
+.B nokeyrings
+utility runs a specified
+.IR utility ,
+but mounts
+.I /var/empty
+over
+.IR ~/.local/share/keyrings ,
+if both directories exist, (failure is ignored)
+for that process and its children, effectively
+hiding the user's keyrings.
+
+.SH OPTIONS
+No options are supported.
+
+.SH OPERANDS
+The following operands are supported:
+.TP
+.I utility
+The name of the utility to be invoked.
+.TP
+.I argument
+A string to pass as an argument for the invoked utility.
+
+.SH STDIN
+Not used.
+
+.SH INPUT FILES
+None.
+
+.SH ENVIRONMENT VARIABLES
+The following environment variables affect
+the execution of
+.BR nokeyrings :
+.TP
+.B PATH
+Determine the location of the
+.IR utility ,
+as described in the Base Definitions volume of POSIX.1‐2017,
+.IR "Chapter 8, Environment Variables" .
+
+.SH STDOUT
+Not used.
+
+.SH STDERR
+The standard error is be used only for diagnostic messages.
+
+.SH OUTPUT FILES
+None.
+
+.SJ EXIT STATUS
+If
+.I utility
+is invoked, the exit status of
+.B nokeyrings
+is the exit status of
+.IR utility ;
+otherwise, the
+.B nokeyrings
+utility exits with one of the following values:
+.TP
+125
+An error occurred in the
+.B nokeyrings
+utility.
+.TP
+126
+The utility specified by
+.I utility
+was found but could not be invoked.
+.TP
+127
+The utility sspecified by
+.I utility
+could not be found.
+
+.SH RATIONALE
+The
+.B nokeyrings
+utility can be used as a wrapper around programs
+that nags the user about entering his password to access a
+keyring, if he does it use it but the keyring is tightly
+integrated into the OS distribution and cannot easily be removed.
+
+.SH SEE ALSO
+None.
diff --git a/nokeyrings.c b/nokeyrings.c
new file mode 100644
index 0000000..aaa32c7
--- /dev/null
+++ b/nokeyrings.c
@@ -0,0 +1,127 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/mount.h>
+#ifndef OPEN_TREE_CLONE
+# define MISSING_OPEN_TREE
+#endif
+#ifndef MOVE_MOUNT_F_EMPTY_PATH
+# define MISSING_MOVE_MOUNT
+#endif
+#if defined(MISSING_OPEN_TREE) || defined(MISSING_MOVE_MOUNT)
+# include <linux/mount.h>
+# include <sys/syscall.h>
+#endif
+#include <sched.h>
+#include <libsimple.h>
+#include <libsimple-arg.h>
+
+NUSAGE(125, "utility [argument] ...");
+
+
+
+#ifdef MISSING_OPEN_TREE
+static int
+open_tree(int dirfd, const char *path, int flags)
+{
+	return syscall(SYS_open_tree, dirfd, path, flags);
+}
+#endif
+
+
+#ifdef MISSING_MOVE_MOUNT
+static int
+move_mount(int dirfd1, const char *path1, int dirfd2, const char *path2, int flags)
+{
+	return syscall(SYS_move_mount, dirfd1, path1, dirfd2, path2, flags);
+}
+#endif
+
+
+int
+main(int argc, char *argv[])
+{
+	struct stat st;
+	int emptyfd = -1;
+	int keyringsfd = -1;
+	char *path = NULL;
+	struct passwd *pwd;
+
+	libsimple_default_failure_exit = 125;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (!argc)
+		usage();
+
+	errno = 0;
+	pwd = getpwuid(getuid());
+	if (!pwd) {
+		if (!errno) {
+			eprintf("your user does not exist");
+		} else if (errno == EIO) {
+			weprintf("getpwuid <real user>:");
+			eprintf("this usually indicates that the user not exist");
+		} else {
+			eprintf("getpwuid <real user>:");
+		}
+	}
+	if (!pwd->pw_dir || !*pwd->pw_dir)
+		eprintf("your user does not have a home directory");
+
+	path = emalloc(strlen(pwd->pw_dir) + sizeof("/.local/share/keyrings"));
+	stpcpy(stpcpy(path, pwd->pw_dir), "/.local/share/keyrings");
+
+	keyringsfd = open(path, O_DIRECTORY);
+	if (keyringsfd < 0) {
+		if (errno != ENOENT)
+			weprintf("open %s O_DIRECTORY:", path);
+		goto exec;
+	}
+
+	if (unshare(CLONE_NEWNS)) {
+		weprintf("unshare CLONE_NEWNS:");
+		goto exec;
+	}
+	if (mount("none", "/", NULL, MS_REC | MS_SLAVE, NULL)) {
+		weprintf("mount none / NULL MS_REC|MS_SLAVE NULL:");
+		goto exec;
+	}
+
+	emptyfd = open_tree(AT_FDCWD, "/var/empty", OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC);
+	if (emptyfd < 0) {
+		weprintf("open_tree AT_FDCWD /var/empty OPEN_TREE_CLONE|OPEN_TREE_CLOEXEC:");
+		goto exec;
+	}
+
+	if (fstatat(emptyfd, "", &st, AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW)) {
+		weprintf("fstatat /var/empty \"\" <buffer> AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW:");
+		goto exec;
+	}
+	if (!S_ISDIR(st.st_mode)) {
+		weprintf("/var/empty exists but is not a directory:");
+		goto exec;
+	}
+
+	if (move_mount(emptyfd, "", AT_FDCWD, path, MOVE_MOUNT_F_EMPTY_PATH)) {
+		weprintf("move_mount /var/empty \"\" AT_FDCWD %s MOVE_MOUNT_F_EMPTY_PATH:", path);
+		goto exec;
+	}
+
+exec:
+	free(path);
+	if (emptyfd >= 0)
+		close(emptyfd);
+	if (keyringsfd >= 0)
+		close(keyringsfd);
+
+	if (setegid(getgid()))
+		eprintf("setegid <real group>:");
+	if (seteuid(getuid()))
+		eprintf("seteuid <real user>:");
+
+	execvp(argv[0], argv);
+	enprintf(errno == ENOENT ? 127 : 126, "execvp %s:", argv[0]);
+	return 0;
+}