Adding upstream version 1:5.44.upstream/1%5.44upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 289 insertions, 0 deletions

diff --git a/src/seccomp.c b/src/seccomp.c
new file mode 100644
index 0000000..70d9b10
--- /dev/null
+++ b/src/seccomp.c
@@ -0,0 +1,289 @@
+/*
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice immediately at the beginning of the file, without modification,
+ *    this list of conditions, and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * libseccomp hooks.
+ */
+#include "file.h"
+
+#ifndef	lint
+FILE_RCSID("@(#)$File: seccomp.c,v 1.24 2022/09/24 20:30:13 christos Exp $")
+#endif	/* lint */
+
+#if HAVE_LIBSECCOMP
+#include <seccomp.h> /* libseccomp */
+#include <sys/prctl.h> /* prctl */
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <termios.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#define DENY_RULE(call) \
+    do \
+	if (seccomp_rule_add (ctx, SCMP_ACT_KILL, SCMP_SYS(call), 0) == -1) \
+	    goto out; \
+    while (/*CONSTCOND*/0)
+#define ALLOW_RULE(call) \
+    do \
+	if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(call), 0) == -1) \
+	    goto out; \
+    while (/*CONSTCOND*/0)
+
+#define ALLOW_IOCTL_RULE(param) \
+    do \
+	if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1, \
+	    SCMP_CMP(1, SCMP_CMP_EQ, (scmp_datum_t)param, \
+		     (scmp_datum_t)0)) == -1) \
+		goto out; \
+    while (/*CONSTCOND*/0)
+
+static scmp_filter_ctx ctx;
+
+int
+enable_sandbox_basic(void)
+{
+
+	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
+		return -1;
+
+	if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) == -1)
+		return -1;
+
+	// initialize the filter
+	ctx = seccomp_init(SCMP_ACT_ALLOW);
+	if (ctx == NULL)
+	    return 1;
+
+	DENY_RULE(_sysctl);
+	DENY_RULE(acct);
+	DENY_RULE(add_key);
+	DENY_RULE(adjtimex);
+	DENY_RULE(chroot);
+	DENY_RULE(clock_adjtime);
+	DENY_RULE(create_module);
+	DENY_RULE(delete_module);
+	DENY_RULE(fanotify_init);
+	DENY_RULE(finit_module);
+	DENY_RULE(get_kernel_syms);
+	DENY_RULE(get_mempolicy);
+	DENY_RULE(init_module);
+	DENY_RULE(io_cancel);
+	DENY_RULE(io_destroy);
+	DENY_RULE(io_getevents);
+	DENY_RULE(io_setup);
+	DENY_RULE(io_submit);
+	DENY_RULE(ioperm);
+	DENY_RULE(iopl);
+	DENY_RULE(ioprio_set);
+	DENY_RULE(kcmp);
+#ifdef __NR_kexec_file_load
+	DENY_RULE(kexec_file_load);
+#endif
+	DENY_RULE(kexec_load);
+	DENY_RULE(keyctl);
+	DENY_RULE(lookup_dcookie);
+	DENY_RULE(mbind);
+	DENY_RULE(nfsservctl);
+	DENY_RULE(migrate_pages);
+	DENY_RULE(modify_ldt);
+	DENY_RULE(mount);
+	DENY_RULE(move_pages);
+	DENY_RULE(name_to_handle_at);
+	DENY_RULE(open_by_handle_at);
+	DENY_RULE(perf_event_open);
+	DENY_RULE(pivot_root);
+	DENY_RULE(process_vm_readv);
+	DENY_RULE(process_vm_writev);
+	DENY_RULE(ptrace);
+	DENY_RULE(reboot);
+	DENY_RULE(remap_file_pages);
+	DENY_RULE(request_key);
+	DENY_RULE(set_mempolicy);
+	DENY_RULE(swapoff);
+	DENY_RULE(swapon);
+	DENY_RULE(sysfs);
+	DENY_RULE(syslog);
+	DENY_RULE(tuxcall);
+	DENY_RULE(umount2);
+	DENY_RULE(uselib);
+	DENY_RULE(vmsplice);
+
+	// blocking dangerous syscalls that file should not need
+	DENY_RULE (execve);
+	DENY_RULE (socket);
+	// ...
+
+
+	// applying filter...
+	if (seccomp_load (ctx) == -1)
+		goto out;
+	// free ctx after the filter has been loaded into the kernel
+	seccomp_release(ctx);
+	return 0;
+
+out:
+	seccomp_release(ctx);
+	return -1;
+}
+
+
+int
+enable_sandbox_full(void)
+{
+
+	// prevent child processes from getting more priv e.g. via setuid,
+	// capabilities, ...
+	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
+		return -1;
+
+	if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) == -1)
+		return -1;
+
+	// initialize the filter
+	ctx = seccomp_init(SCMP_ACT_KILL);
+	if (ctx == NULL)
+		return -1;
+
+	ALLOW_RULE(access);
+	ALLOW_RULE(brk);
+	ALLOW_RULE(close);
+	ALLOW_RULE(dup2);
+	ALLOW_RULE(exit);
+	ALLOW_RULE(exit_group);
+#ifdef __NR_faccessat
+	ALLOW_RULE(faccessat);
+#endif
+	ALLOW_RULE(fcntl);
+ 	ALLOW_RULE(fcntl64);
+#ifdef __NR_fstat
+	ALLOW_RULE(fstat);
+#endif
+ 	ALLOW_RULE(fstat64);
+#ifdef __NR_fstatat64
+	ALLOW_RULE(fstatat64);
+#endif
+	ALLOW_RULE(futex);
+	ALLOW_RULE(getdents);
+#ifdef __NR_getdents64
+	ALLOW_RULE(getdents64);
+#endif
+#ifdef FIONREAD
+	// called in src/compress.c under sread
+	ALLOW_IOCTL_RULE(FIONREAD);
+#endif
+#ifdef TIOCGWINSZ
+	// musl libc may call ioctl TIOCGWINSZ on stdout
+	ALLOW_IOCTL_RULE(TIOCGWINSZ);
+#endif
+#ifdef TCGETS
+	// glibc may call ioctl TCGETS on stdout on physical terminal
+	ALLOW_IOCTL_RULE(TCGETS);
+#endif
+	ALLOW_RULE(lseek);
+ 	ALLOW_RULE(_llseek);
+	ALLOW_RULE(lstat);
+ 	ALLOW_RULE(lstat64);
+	ALLOW_RULE(madvise);
+	ALLOW_RULE(mmap);
+ 	ALLOW_RULE(mmap2);
+	ALLOW_RULE(mprotect);
+	ALLOW_RULE(mremap);
+	ALLOW_RULE(munmap);
+#ifdef __NR_newfstatat
+	ALLOW_RULE(newfstatat);
+#endif
+	ALLOW_RULE(open);
+	ALLOW_RULE(openat);
+	ALLOW_RULE(pread64);
+	ALLOW_RULE(read);
+	ALLOW_RULE(readlink);
+#ifdef __NR_readlinkat
+	ALLOW_RULE(readlinkat);
+#endif
+	ALLOW_RULE(rt_sigaction);
+	ALLOW_RULE(rt_sigprocmask);
+	ALLOW_RULE(rt_sigreturn);
+	ALLOW_RULE(select);
+	ALLOW_RULE(stat);
+	ALLOW_RULE(statx);
+	ALLOW_RULE(stat64);
+	ALLOW_RULE(sysinfo);
+	ALLOW_RULE(umask);	// Used in file_pipe2file()
+	ALLOW_RULE(getpid);	// Used by glibc in file_pipe2file()
+	ALLOW_RULE(unlink);
+	ALLOW_RULE(write);
+	ALLOW_RULE(writev);
+
+
+#if 0
+	// needed by valgrind
+	ALLOW_RULE(gettid);
+	ALLOW_RULE(rt_sigtimedwait);
+#endif
+
+#if 0
+	 /* special restrictions for socket, only allow AF_UNIX/AF_LOCAL */
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 1,
+	     SCMP_CMP(0, SCMP_CMP_EQ, AF_UNIX)) == -1)
+	 	goto out;
+
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 1,
+	     SCMP_CMP(0, SCMP_CMP_EQ, AF_LOCAL)) == -1)
+	 	goto out;
+
+
+	 /* special restrictions for open, prevent opening files for writing */
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 1,
+	     SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) == -1)
+	 	goto out;
+
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open), 1,
+	     SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) == -1)
+	 	goto out;
+
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open), 1,
+	     SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) == -1)
+	 	goto out;
+
+
+	 /* allow stderr */
+	 if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1,
+	     SCMP_CMP(0, SCMP_CMP_EQ, 2)) == -1)
+		 goto out;
+#endif
+
+	// applying filter...
+	if (seccomp_load(ctx) == -1)
+		goto out;
+	// free ctx after the filter has been loaded into the kernel
+	seccomp_release(ctx);
+	return 0;
+
+out:
+	// something went wrong
+	seccomp_release(ctx);
+	return -1;
+}
+#endif