Some basic tests to verify sealing on memfds works as expected and guarantees the advertised semantics. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
			
				
	
	
		
			913 lines
		
	
	
	
		
			18 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			913 lines
		
	
	
	
		
			18 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
#define _GNU_SOURCE
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#define __EXPORTED_HEADERS__
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#include <errno.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <linux/falloc.h>
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#include <linux/fcntl.h>
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#include <linux/memfd.h>
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#include <sched.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#define MFD_DEF_SIZE 8192
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#define STACK_SIZE 65535
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static int sys_memfd_create(const char *name,
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			    unsigned int flags)
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{
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	return syscall(__NR_memfd_create, name, flags);
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}
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static int mfd_assert_new(const char *name, loff_t sz, unsigned int flags)
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{
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	int r, fd;
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	fd = sys_memfd_create(name, flags);
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	if (fd < 0) {
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		printf("memfd_create(\"%s\", %u) failed: %m\n",
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		       name, flags);
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		abort();
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	}
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	r = ftruncate(fd, sz);
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	if (r < 0) {
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		printf("ftruncate(%llu) failed: %m\n", (unsigned long long)sz);
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		abort();
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	}
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	return fd;
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}
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static void mfd_fail_new(const char *name, unsigned int flags)
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{
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	int r;
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	r = sys_memfd_create(name, flags);
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	if (r >= 0) {
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		printf("memfd_create(\"%s\", %u) succeeded, but failure expected\n",
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		       name, flags);
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		close(r);
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		abort();
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	}
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}
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static __u64 mfd_assert_get_seals(int fd)
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{
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	long r;
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	r = fcntl(fd, F_GET_SEALS);
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	if (r < 0) {
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		printf("GET_SEALS(%d) failed: %m\n", fd);
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		abort();
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	}
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	return r;
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}
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static void mfd_assert_has_seals(int fd, __u64 seals)
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{
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	__u64 s;
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	s = mfd_assert_get_seals(fd);
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	if (s != seals) {
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		printf("%llu != %llu = GET_SEALS(%d)\n",
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		       (unsigned long long)seals, (unsigned long long)s, fd);
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		abort();
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	}
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}
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static void mfd_assert_add_seals(int fd, __u64 seals)
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{
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	long r;
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	__u64 s;
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	s = mfd_assert_get_seals(fd);
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	r = fcntl(fd, F_ADD_SEALS, seals);
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	if (r < 0) {
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		printf("ADD_SEALS(%d, %llu -> %llu) failed: %m\n",
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		       fd, (unsigned long long)s, (unsigned long long)seals);
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		abort();
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	}
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}
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static void mfd_fail_add_seals(int fd, __u64 seals)
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{
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	long r;
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	__u64 s;
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	r = fcntl(fd, F_GET_SEALS);
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	if (r < 0)
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		s = 0;
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	else
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		s = r;
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	r = fcntl(fd, F_ADD_SEALS, seals);
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	if (r >= 0) {
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		printf("ADD_SEALS(%d, %llu -> %llu) didn't fail as expected\n",
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		       fd, (unsigned long long)s, (unsigned long long)seals);
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		abort();
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	}
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}
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static void mfd_assert_size(int fd, size_t size)
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{
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	struct stat st;
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	int r;
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	r = fstat(fd, &st);
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	if (r < 0) {
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		printf("fstat(%d) failed: %m\n", fd);
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		abort();
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	} else if (st.st_size != size) {
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		printf("wrong file size %lld, but expected %lld\n",
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		       (long long)st.st_size, (long long)size);
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		abort();
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	}
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}
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static int mfd_assert_dup(int fd)
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{
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	int r;
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	r = dup(fd);
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	if (r < 0) {
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		printf("dup(%d) failed: %m\n", fd);
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		abort();
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	}
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	return r;
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}
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static void *mfd_assert_mmap_shared(int fd)
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{
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	void *p;
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ | PROT_WRITE,
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		 MAP_SHARED,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	return p;
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}
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static void *mfd_assert_mmap_private(int fd)
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{
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	void *p;
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ,
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		 MAP_PRIVATE,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	return p;
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}
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static int mfd_assert_open(int fd, int flags, mode_t mode)
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{
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	char buf[512];
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	int r;
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	sprintf(buf, "/proc/self/fd/%d", fd);
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	r = open(buf, flags, mode);
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	if (r < 0) {
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		printf("open(%s) failed: %m\n", buf);
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		abort();
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	}
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	return r;
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}
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static void mfd_fail_open(int fd, int flags, mode_t mode)
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{
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	char buf[512];
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	int r;
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	sprintf(buf, "/proc/self/fd/%d", fd);
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	r = open(buf, flags, mode);
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	if (r >= 0) {
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		printf("open(%s) didn't fail as expected\n");
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		abort();
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	}
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}
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static void mfd_assert_read(int fd)
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{
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	char buf[16];
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	void *p;
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	ssize_t l;
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	l = read(fd, buf, sizeof(buf));
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	if (l != sizeof(buf)) {
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		printf("read() failed: %m\n");
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		abort();
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	}
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	/* verify PROT_READ *is* allowed */
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ,
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		 MAP_PRIVATE,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	munmap(p, MFD_DEF_SIZE);
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	/* verify MAP_PRIVATE is *always* allowed (even writable) */
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ | PROT_WRITE,
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		 MAP_PRIVATE,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	munmap(p, MFD_DEF_SIZE);
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}
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static void mfd_assert_write(int fd)
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{
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	ssize_t l;
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	void *p;
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	int r;
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	/* verify write() succeeds */
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	l = write(fd, "\0\0\0\0", 4);
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	if (l != 4) {
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		printf("write() failed: %m\n");
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		abort();
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	}
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	/* verify PROT_READ | PROT_WRITE is allowed */
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ | PROT_WRITE,
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		 MAP_SHARED,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	*(char *)p = 0;
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	munmap(p, MFD_DEF_SIZE);
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	/* verify PROT_WRITE is allowed */
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_WRITE,
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		 MAP_SHARED,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	*(char *)p = 0;
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	munmap(p, MFD_DEF_SIZE);
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	/* verify PROT_READ with MAP_SHARED is allowed and a following
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	 * mprotect(PROT_WRITE) allows writing */
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	p = mmap(NULL,
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		 MFD_DEF_SIZE,
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		 PROT_READ,
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		 MAP_SHARED,
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		 fd,
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		 0);
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	if (p == MAP_FAILED) {
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		printf("mmap() failed: %m\n");
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		abort();
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	}
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	r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
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	if (r < 0) {
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		printf("mprotect() failed: %m\n");
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		abort();
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	}
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	*(char *)p = 0;
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	munmap(p, MFD_DEF_SIZE);
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	/* verify PUNCH_HOLE works */
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						|
	r = fallocate(fd,
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		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
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		      0,
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		      MFD_DEF_SIZE);
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						|
	if (r < 0) {
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		printf("fallocate(PUNCH_HOLE) failed: %m\n");
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		abort();
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	}
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}
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static void mfd_fail_write(int fd)
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{
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	ssize_t l;
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	void *p;
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	int r;
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 | 
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	/* verify write() fails */
 | 
						|
	l = write(fd, "data", 4);
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						|
	if (l != -EPERM) {
 | 
						|
		printf("expected EPERM on write(), but got %d: %m\n", (int)l);
 | 
						|
		abort();
 | 
						|
	}
 | 
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 | 
						|
	/* verify PROT_READ | PROT_WRITE is not allowed */
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						|
	p = mmap(NULL,
 | 
						|
		 MFD_DEF_SIZE,
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						|
		 PROT_READ | PROT_WRITE,
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		 MAP_SHARED,
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						|
		 fd,
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						|
		 0);
 | 
						|
	if (p != MAP_FAILED) {
 | 
						|
		printf("mmap() didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
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 | 
						|
	/* verify PROT_WRITE is not allowed */
 | 
						|
	p = mmap(NULL,
 | 
						|
		 MFD_DEF_SIZE,
 | 
						|
		 PROT_WRITE,
 | 
						|
		 MAP_SHARED,
 | 
						|
		 fd,
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						|
		 0);
 | 
						|
	if (p != MAP_FAILED) {
 | 
						|
		printf("mmap() didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	/* Verify PROT_READ with MAP_SHARED with a following mprotect is not
 | 
						|
	 * allowed. Note that for r/w the kernel already prevents the mmap. */
 | 
						|
	p = mmap(NULL,
 | 
						|
		 MFD_DEF_SIZE,
 | 
						|
		 PROT_READ,
 | 
						|
		 MAP_SHARED,
 | 
						|
		 fd,
 | 
						|
		 0);
 | 
						|
	if (p != MAP_FAILED) {
 | 
						|
		r = mprotect(p, MFD_DEF_SIZE, PROT_READ | PROT_WRITE);
 | 
						|
		if (r >= 0) {
 | 
						|
			printf("mmap()+mprotect() didn't fail as expected\n");
 | 
						|
			abort();
 | 
						|
		}
 | 
						|
	}
 | 
						|
 | 
						|
	/* verify PUNCH_HOLE fails */
 | 
						|
	r = fallocate(fd,
 | 
						|
		      FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 | 
						|
		      0,
 | 
						|
		      MFD_DEF_SIZE);
 | 
						|
	if (r >= 0) {
 | 
						|
		printf("fallocate(PUNCH_HOLE) didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_assert_shrink(int fd)
 | 
						|
{
 | 
						|
	int r, fd2;
 | 
						|
 | 
						|
	r = ftruncate(fd, MFD_DEF_SIZE / 2);
 | 
						|
	if (r < 0) {
 | 
						|
		printf("ftruncate(SHRINK) failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	mfd_assert_size(fd, MFD_DEF_SIZE / 2);
 | 
						|
 | 
						|
	fd2 = mfd_assert_open(fd,
 | 
						|
			      O_RDWR | O_CREAT | O_TRUNC,
 | 
						|
			      S_IRUSR | S_IWUSR);
 | 
						|
	close(fd2);
 | 
						|
 | 
						|
	mfd_assert_size(fd, 0);
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_fail_shrink(int fd)
 | 
						|
{
 | 
						|
	int r;
 | 
						|
 | 
						|
	r = ftruncate(fd, MFD_DEF_SIZE / 2);
 | 
						|
	if (r >= 0) {
 | 
						|
		printf("ftruncate(SHRINK) didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	mfd_fail_open(fd,
 | 
						|
		      O_RDWR | O_CREAT | O_TRUNC,
 | 
						|
		      S_IRUSR | S_IWUSR);
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_assert_grow(int fd)
 | 
						|
{
 | 
						|
	int r;
 | 
						|
 | 
						|
	r = ftruncate(fd, MFD_DEF_SIZE * 2);
 | 
						|
	if (r < 0) {
 | 
						|
		printf("ftruncate(GROW) failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	mfd_assert_size(fd, MFD_DEF_SIZE * 2);
 | 
						|
 | 
						|
	r = fallocate(fd,
 | 
						|
		      0,
 | 
						|
		      0,
 | 
						|
		      MFD_DEF_SIZE * 4);
 | 
						|
	if (r < 0) {
 | 
						|
		printf("fallocate(ALLOC) failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	mfd_assert_size(fd, MFD_DEF_SIZE * 4);
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_fail_grow(int fd)
 | 
						|
{
 | 
						|
	int r;
 | 
						|
 | 
						|
	r = ftruncate(fd, MFD_DEF_SIZE * 2);
 | 
						|
	if (r >= 0) {
 | 
						|
		printf("ftruncate(GROW) didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	r = fallocate(fd,
 | 
						|
		      0,
 | 
						|
		      0,
 | 
						|
		      MFD_DEF_SIZE * 4);
 | 
						|
	if (r >= 0) {
 | 
						|
		printf("fallocate(ALLOC) didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_assert_grow_write(int fd)
 | 
						|
{
 | 
						|
	static char buf[MFD_DEF_SIZE * 8];
 | 
						|
	ssize_t l;
 | 
						|
 | 
						|
	l = pwrite(fd, buf, sizeof(buf), 0);
 | 
						|
	if (l != sizeof(buf)) {
 | 
						|
		printf("pwrite() failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	mfd_assert_size(fd, MFD_DEF_SIZE * 8);
 | 
						|
}
 | 
						|
 | 
						|
static void mfd_fail_grow_write(int fd)
 | 
						|
{
 | 
						|
	static char buf[MFD_DEF_SIZE * 8];
 | 
						|
	ssize_t l;
 | 
						|
 | 
						|
	l = pwrite(fd, buf, sizeof(buf), 0);
 | 
						|
	if (l == sizeof(buf)) {
 | 
						|
		printf("pwrite() didn't fail as expected\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static int idle_thread_fn(void *arg)
 | 
						|
{
 | 
						|
	sigset_t set;
 | 
						|
	int sig;
 | 
						|
 | 
						|
	/* dummy waiter; SIGTERM terminates us anyway */
 | 
						|
	sigemptyset(&set);
 | 
						|
	sigaddset(&set, SIGTERM);
 | 
						|
	sigwait(&set, &sig);
 | 
						|
 | 
						|
	return 0;
 | 
						|
}
 | 
						|
 | 
						|
static pid_t spawn_idle_thread(unsigned int flags)
 | 
						|
{
 | 
						|
	uint8_t *stack;
 | 
						|
	pid_t pid;
 | 
						|
 | 
						|
	stack = malloc(STACK_SIZE);
 | 
						|
	if (!stack) {
 | 
						|
		printf("malloc(STACK_SIZE) failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	pid = clone(idle_thread_fn,
 | 
						|
		    stack + STACK_SIZE,
 | 
						|
		    SIGCHLD | flags,
 | 
						|
		    NULL);
 | 
						|
	if (pid < 0) {
 | 
						|
		printf("clone() failed: %m\n");
 | 
						|
		abort();
 | 
						|
	}
 | 
						|
 | 
						|
	return pid;
 | 
						|
}
 | 
						|
 | 
						|
static void join_idle_thread(pid_t pid)
 | 
						|
{
 | 
						|
	kill(pid, SIGTERM);
 | 
						|
	waitpid(pid, NULL, 0);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test memfd_create() syscall
 | 
						|
 * Verify syscall-argument validation, including name checks, flag validation
 | 
						|
 * and more.
 | 
						|
 */
 | 
						|
static void test_create(void)
 | 
						|
{
 | 
						|
	char buf[2048];
 | 
						|
	int fd;
 | 
						|
 | 
						|
	/* test NULL name */
 | 
						|
	mfd_fail_new(NULL, 0);
 | 
						|
 | 
						|
	/* test over-long name (not zero-terminated) */
 | 
						|
	memset(buf, 0xff, sizeof(buf));
 | 
						|
	mfd_fail_new(buf, 0);
 | 
						|
 | 
						|
	/* test over-long zero-terminated name */
 | 
						|
	memset(buf, 0xff, sizeof(buf));
 | 
						|
	buf[sizeof(buf) - 1] = 0;
 | 
						|
	mfd_fail_new(buf, 0);
 | 
						|
 | 
						|
	/* verify "" is a valid name */
 | 
						|
	fd = mfd_assert_new("", 0, 0);
 | 
						|
	close(fd);
 | 
						|
 | 
						|
	/* verify invalid O_* open flags */
 | 
						|
	mfd_fail_new("", 0x0100);
 | 
						|
	mfd_fail_new("", ~MFD_CLOEXEC);
 | 
						|
	mfd_fail_new("", ~MFD_ALLOW_SEALING);
 | 
						|
	mfd_fail_new("", ~0);
 | 
						|
	mfd_fail_new("", 0x80000000U);
 | 
						|
 | 
						|
	/* verify MFD_CLOEXEC is allowed */
 | 
						|
	fd = mfd_assert_new("", 0, MFD_CLOEXEC);
 | 
						|
	close(fd);
 | 
						|
 | 
						|
	/* verify MFD_ALLOW_SEALING is allowed */
 | 
						|
	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING);
 | 
						|
	close(fd);
 | 
						|
 | 
						|
	/* verify MFD_ALLOW_SEALING | MFD_CLOEXEC is allowed */
 | 
						|
	fd = mfd_assert_new("", 0, MFD_ALLOW_SEALING | MFD_CLOEXEC);
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test basic sealing
 | 
						|
 * A very basic sealing test to see whether setting/retrieving seals works.
 | 
						|
 */
 | 
						|
static void test_basic(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_basic",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
 | 
						|
	/* add basic seals */
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
 | 
						|
				 F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 | 
						|
				 F_SEAL_WRITE);
 | 
						|
 | 
						|
	/* add them again */
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SHRINK |
 | 
						|
				 F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 | 
						|
				 F_SEAL_WRITE);
 | 
						|
 | 
						|
	/* add more seals and seal against sealing */
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_GROW | F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK |
 | 
						|
				 F_SEAL_GROW |
 | 
						|
				 F_SEAL_WRITE |
 | 
						|
				 F_SEAL_SEAL);
 | 
						|
 | 
						|
	/* verify that sealing no longer works */
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_GROW);
 | 
						|
	mfd_fail_add_seals(fd, 0);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
 | 
						|
	/* verify sealing does not work without MFD_ALLOW_SEALING */
 | 
						|
	fd = mfd_assert_new("kern_memfd_basic",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_SHRINK |
 | 
						|
			       F_SEAL_GROW |
 | 
						|
			       F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test SEAL_WRITE
 | 
						|
 * Test whether SEAL_WRITE actually prevents modifications.
 | 
						|
 */
 | 
						|
static void test_seal_write(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_seal_write",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE);
 | 
						|
 | 
						|
	mfd_assert_read(fd);
 | 
						|
	mfd_fail_write(fd);
 | 
						|
	mfd_assert_shrink(fd);
 | 
						|
	mfd_assert_grow(fd);
 | 
						|
	mfd_fail_grow_write(fd);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test SEAL_SHRINK
 | 
						|
 * Test whether SEAL_SHRINK actually prevents shrinking
 | 
						|
 */
 | 
						|
static void test_seal_shrink(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_seal_shrink",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
 | 
						|
 | 
						|
	mfd_assert_read(fd);
 | 
						|
	mfd_assert_write(fd);
 | 
						|
	mfd_fail_shrink(fd);
 | 
						|
	mfd_assert_grow(fd);
 | 
						|
	mfd_assert_grow_write(fd);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test SEAL_GROW
 | 
						|
 * Test whether SEAL_GROW actually prevents growing
 | 
						|
 */
 | 
						|
static void test_seal_grow(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_seal_grow",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_GROW);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_GROW);
 | 
						|
 | 
						|
	mfd_assert_read(fd);
 | 
						|
	mfd_assert_write(fd);
 | 
						|
	mfd_assert_shrink(fd);
 | 
						|
	mfd_fail_grow(fd);
 | 
						|
	mfd_fail_grow_write(fd);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test SEAL_SHRINK | SEAL_GROW
 | 
						|
 * Test whether SEAL_SHRINK | SEAL_GROW actually prevents resizing
 | 
						|
 */
 | 
						|
static void test_seal_resize(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_seal_resize",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK | F_SEAL_GROW);
 | 
						|
 | 
						|
	mfd_assert_read(fd);
 | 
						|
	mfd_assert_write(fd);
 | 
						|
	mfd_fail_shrink(fd);
 | 
						|
	mfd_fail_grow(fd);
 | 
						|
	mfd_fail_grow_write(fd);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test sharing via dup()
 | 
						|
 * Test that seals are shared between dupped FDs and they're all equal.
 | 
						|
 */
 | 
						|
static void test_share_dup(void)
 | 
						|
{
 | 
						|
	int fd, fd2;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_share_dup",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
 | 
						|
	fd2 = mfd_assert_dup(fd);
 | 
						|
	mfd_assert_has_seals(fd2, 0);
 | 
						|
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
 | 
						|
 | 
						|
	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 | 
						|
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_GROW);
 | 
						|
	mfd_fail_add_seals(fd2, F_SEAL_GROW);
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_SEAL);
 | 
						|
	mfd_fail_add_seals(fd2, F_SEAL_SEAL);
 | 
						|
 | 
						|
	close(fd2);
 | 
						|
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_GROW);
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test sealing with active mmap()s
 | 
						|
 * Modifying seals is only allowed if no other mmap() refs exist.
 | 
						|
 */
 | 
						|
static void test_share_mmap(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
	void *p;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_share_mmap",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
 | 
						|
	/* shared/writable ref prevents sealing WRITE, but allows others */
 | 
						|
	p = mfd_assert_mmap_shared(fd);
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SHRINK);
 | 
						|
	munmap(p, MFD_DEF_SIZE);
 | 
						|
 | 
						|
	/* readable ref allows sealing */
 | 
						|
	p = mfd_assert_mmap_private(fd);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
	munmap(p, MFD_DEF_SIZE);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test sealing with open(/proc/self/fd/%d)
 | 
						|
 * Via /proc we can get access to a separate file-context for the same memfd.
 | 
						|
 * This is *not* like dup(), but like a real separate open(). Make sure the
 | 
						|
 * semantics are as expected and we correctly check for RDONLY / WRONLY / RDWR.
 | 
						|
 */
 | 
						|
static void test_share_open(void)
 | 
						|
{
 | 
						|
	int fd, fd2;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_share_open",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
 | 
						|
	fd2 = mfd_assert_open(fd, O_RDWR, 0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE);
 | 
						|
 | 
						|
	mfd_assert_add_seals(fd2, F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
	fd = mfd_assert_open(fd2, O_RDONLY, 0);
 | 
						|
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 | 
						|
 | 
						|
	close(fd2);
 | 
						|
	fd2 = mfd_assert_open(fd, O_RDWR, 0);
 | 
						|
 | 
						|
	mfd_assert_add_seals(fd2, F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 | 
						|
 | 
						|
	close(fd2);
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
 * Test sharing via fork()
 | 
						|
 * Test whether seal-modifications work as expected with forked childs.
 | 
						|
 */
 | 
						|
static void test_share_fork(void)
 | 
						|
{
 | 
						|
	int fd;
 | 
						|
	pid_t pid;
 | 
						|
 | 
						|
	fd = mfd_assert_new("kern_memfd_share_fork",
 | 
						|
			    MFD_DEF_SIZE,
 | 
						|
			    MFD_CLOEXEC | MFD_ALLOW_SEALING);
 | 
						|
	mfd_assert_has_seals(fd, 0);
 | 
						|
 | 
						|
	pid = spawn_idle_thread(0);
 | 
						|
	mfd_assert_add_seals(fd, F_SEAL_SEAL);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
 | 
						|
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
 | 
						|
 | 
						|
	join_idle_thread(pid);
 | 
						|
 | 
						|
	mfd_fail_add_seals(fd, F_SEAL_WRITE);
 | 
						|
	mfd_assert_has_seals(fd, F_SEAL_SEAL);
 | 
						|
 | 
						|
	close(fd);
 | 
						|
}
 | 
						|
 | 
						|
int main(int argc, char **argv)
 | 
						|
{
 | 
						|
	pid_t pid;
 | 
						|
 | 
						|
	printf("memfd: CREATE\n");
 | 
						|
	test_create();
 | 
						|
	printf("memfd: BASIC\n");
 | 
						|
	test_basic();
 | 
						|
 | 
						|
	printf("memfd: SEAL-WRITE\n");
 | 
						|
	test_seal_write();
 | 
						|
	printf("memfd: SEAL-SHRINK\n");
 | 
						|
	test_seal_shrink();
 | 
						|
	printf("memfd: SEAL-GROW\n");
 | 
						|
	test_seal_grow();
 | 
						|
	printf("memfd: SEAL-RESIZE\n");
 | 
						|
	test_seal_resize();
 | 
						|
 | 
						|
	printf("memfd: SHARE-DUP\n");
 | 
						|
	test_share_dup();
 | 
						|
	printf("memfd: SHARE-MMAP\n");
 | 
						|
	test_share_mmap();
 | 
						|
	printf("memfd: SHARE-OPEN\n");
 | 
						|
	test_share_open();
 | 
						|
	printf("memfd: SHARE-FORK\n");
 | 
						|
	test_share_fork();
 | 
						|
 | 
						|
	/* Run test-suite in a multi-threaded environment with a shared
 | 
						|
	 * file-table. */
 | 
						|
	pid = spawn_idle_thread(CLONE_FILES | CLONE_FS | CLONE_VM);
 | 
						|
	printf("memfd: SHARE-DUP (shared file-table)\n");
 | 
						|
	test_share_dup();
 | 
						|
	printf("memfd: SHARE-MMAP (shared file-table)\n");
 | 
						|
	test_share_mmap();
 | 
						|
	printf("memfd: SHARE-OPEN (shared file-table)\n");
 | 
						|
	test_share_open();
 | 
						|
	printf("memfd: SHARE-FORK (shared file-table)\n");
 | 
						|
	test_share_fork();
 | 
						|
	join_idle_thread(pid);
 | 
						|
 | 
						|
	printf("memfd: DONE\n");
 | 
						|
 | 
						|
	return 0;
 | 
						|
}
 |