Index: sys/amd64/linux/linux_dummy.c
===================================================================
--- sys/amd64/linux/linux_dummy.c
+++ sys/amd64/linux/linux_dummy.c
@@ -134,7 +134,6 @@
 /* Linux 3.15: */
 DUMMY(kexec_file_load);
 /* Linux 3.17: */
-DUMMY(memfd_create);
 DUMMY(seccomp);
 /* Linux 3.18: */
 DUMMY(bpf);
Index: sys/amd64/linux32/linux32_dummy.c
===================================================================
--- sys/amd64/linux32/linux32_dummy.c
+++ sys/amd64/linux32/linux32_dummy.c
@@ -138,7 +138,6 @@
 DUMMY(sched_setattr);
 DUMMY(sched_getattr);
 /* Linux 3.17: */
-DUMMY(memfd_create);
 DUMMY(seccomp);
 /* Linux 3.18: */
 DUMMY(bpf);
Index: sys/arm64/linux/linux_dummy.c
===================================================================
--- sys/arm64/linux/linux_dummy.c
+++ sys/arm64/linux/linux_dummy.c
@@ -132,7 +132,6 @@
 DUMMY(sched_setattr);
 DUMMY(sched_getattr);
 /* Linux 3.17: */
-DUMMY(memfd_create);
 DUMMY(seccomp);
 /* Linux 3.18: */
 DUMMY(bpf);
Index: sys/compat/linux/linux_file.h
===================================================================
--- sys/compat/linux/linux_file.h
+++ sys/compat/linux/linux_file.h
@@ -113,6 +113,9 @@
 #define	LINUX_F_SETPIPE_SZ	(LINUX_F_SPECIFIC_BASE + 7)
 #define	LINUX_F_GETPIPE_SZ	(LINUX_F_SPECIFIC_BASE + 8)
 
+#define	LINUX_F_ADD_SEALS	(LINUX_F_SPECIFIC_BASE + 9)
+#define	LINUX_F_GET_SEALS	(LINUX_F_SPECIFIC_BASE + 10)
+
 #define	LINUX_F_GETLKP		36
 #define	LINUX_F_SETLKP		37
 #define	LINUX_F_SETLKPW		38
Index: sys/compat/linux/linux_file.c
===================================================================
--- sys/compat/linux/linux_file.c
+++ sys/compat/linux/linux_file.c
@@ -41,6 +41,7 @@
 #include <sys/filedesc.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
+#include <sys/mman.h>
 #include <sys/mount.h>
 #include <sys/mutex.h>
 #include <sys/namei.h>
@@ -1296,6 +1297,16 @@
 
 	case LINUX_F_DUPFD_CLOEXEC:
 		return (kern_fcntl(td, args->fd, F_DUPFD_CLOEXEC, args->arg));
+
+	/*
+	 * Our F_SEAL_* values match Linux one for maximum compatibility.  So we
+	 * only needed to account for different values for fcntl(2) commands.
+	 */
+	case LINUX_F_GET_SEALS:
+		return (kern_fcntl(td, args->fd, F_GET_SEALS, 0));
+
+	case LINUX_F_ADD_SEALS:
+		return (kern_fcntl(td, args->fd, F_ADD_SEALS, args->arg));
 	}
 
 	return (EINVAL);
@@ -1537,3 +1548,46 @@
 	return (kern_posix_fallocate(td, args->fd, args->offset,
 	    args->len));
 }
+
+#define	LINUX_MEMFD_PREFIX	"memfd:"
+
+int
+linux_memfd_create(struct thread *td, struct linux_memfd_create_args *args)
+{
+	char memfd_name[LINUX_NAME_MAX + 1];
+	int error, flags, shmflags, oflags;
+
+	/*
+	 * This is our clever trick to avoid the heap allocation to copy in the
+	 * uname.  We don't really need to go this far out of our way, but it
+	 * does keep the rest of this function fairly clean as they don't have
+	 * to worry about cleanup on the way out.
+	 */
+	error = copyinstr(args->uname_ptr,
+	    memfd_name + sizeof(LINUX_MEMFD_PREFIX) - 1,
+	    LINUX_NAME_MAX - sizeof(LINUX_MEMFD_PREFIX) - 1, NULL);
+	if (error != 0) {
+		if (error == ENAMETOOLONG)
+			error = EINVAL;
+		return (error);
+	}
+
+	memcpy(memfd_name, LINUX_MEMFD_PREFIX, sizeof(LINUX_MEMFD_PREFIX) - 1);
+	flags = args->flags;
+	if ((flags & ~(MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB |
+	    MFD_HUGE_MASK)) != 0)
+		return (EINVAL);
+	/* Size specified but no HUGETLB. */
+	if ((flags & MFD_HUGE_MASK) != 0 && (flags & MFD_HUGETLB) == 0)
+		return (EINVAL);
+	/* We don't actually support HUGETLB. */
+	if ((flags & MFD_HUGETLB) != 0)
+		return (ENOSYS);
+	oflags = O_RDWR;
+	shmflags = 0;
+	if ((flags & MFD_CLOEXEC) != 0)
+		oflags |= O_CLOEXEC;
+	if ((flags & MFD_ALLOW_SEALING) != 0)
+		shmflags |= SHM_ALLOW_SEALING;
+	return (kern_shm_open2(td, SHM_ANON, oflags, 0, shmflags, memfd_name));
+}
Index: sys/i386/linux/linux_dummy.c
===================================================================
--- sys/i386/linux/linux_dummy.c
+++ sys/i386/linux/linux_dummy.c
@@ -134,7 +134,6 @@
 DUMMY(sched_setattr);
 DUMMY(sched_getattr);
 /* Linux 3.17: */
-DUMMY(memfd_create);
 DUMMY(seccomp);
 /* Linux 3.18: */
 DUMMY(bpf);